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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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SECOND INTERNATIONAL CONFERENCE ON ENGINEERING RESEARCH & DEVELOPMENT: INNOVATIONS (ICER&D 2008)

University of Benin, Benin City, Nigeria 15 – 17 April 2008 CONFERENCE PROCEEDINGS (Including Conference Programme)

Sponsors  University of Benin, Benin City  Energy Commission of Nigeria, Abuja  National Agency for Science & Engineering Infrastructure (NASENI), Abuja  Nigerian Gas Company, Ekpan-Warri  National Automotive Council, Abuja

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Welcome On behalf of the Vice-Chancellor, University of Benin, Professor E.A.C. Nwanze, I welcome you to the International Conference on Engineering Research and Development: Innovations (ICER&D) 2008 hosted by the Faculty of Engineering, University of Benin, Nigeria. The main aims of the conference are:  To bring together researchers and practitioners working in all areas of Engineering Research and Development (R & D) to discuss existing/potential impacts of their work on industrial operations.  To expose engineering R & D opportunities in Africa which will encourage collaboration among researchers and links with the rest of the world.  To provide an interface between research institutions and industries on emerging technologies.  To find global partners for research and business collaboration It is therefore hoped that this conference will foster greater interaction between African scientists and engineers and their international counterparts on one hand and between the former and industry on the other. The overall aim is that this will stimulate increased local and foreign investments and corporate presence in Africa. We wish you fruitful deliberations and enjoyable stay in Benin. Thank you.

Professor A.O. Akii Ibhadode Conference Chairman and Dean, Faculty of Engineering

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria ORGANISING COMMITTEE / COMITÉ CHARGÉ DE L’ORGANISATION Chief Host / Hôte Prof. E.A.C. Nwanze, Vice - Chancellor University of Benin, Benin City. Host/Conference Chairman /Hôte/Président de la Conférence. Prof. Akii Ibhadode, Dean/Doyen Faculty of Engineering, University of Benin Local Conference Advisors / Comité Consultatif Local Prof. D.N. Nwokoye Prof. B.O. Onyekpe Prof. P.A. Kuale Prof. J.C. Nwachukwu Prof. T.O.K. Audu Prof. F.F.O. Orumwense Prof. L.A. Salami Prof. F.O. Edeko Prof. E.N. Ohwovoriole Dr. G.C. Ovuworie Prof. J.O. Asalor Dr. B.U. Anyata Prof. R.O. Ebewele Dr. U.J. Udosen

Dr. B.M. Rai Dr. K.I. Idigbe Dr. A.N. Aniekwu Dr. O.E. Alutu Dr. C.A. Ebiogwu Dr. (Mrs) C.O. Okieimen

Language Consultant / Expert - Conseil de Langue Prof. Cyril Mokwenye Organising Committee / Comité chargé de l’organisation Akii Ibhadode N.P. Orobor K.O. Obahiagbon J.O. Ehiorobo D. I. Igbinonwanhia S.O. Osuji J.A. Akpobi G.O. Ariavie F.A. Aisien E.S. Adewole P.E. Amiolemhen S.O. Igbinovia A.C. Igboanugo E.O. Nwaokolo (Mrs.) C.N. Owabor A.I. Igbafe M.E. Emiantor K.O. Osayande J. I. Achebo P. Orere (Mrs) O.S. Odiase E.O.Aluyor R.A. Ebami Technical Committee Dr B U Anyanta Dr A I Igbafe Dr S O Osuji Dr F A Aisien Dr S O Igbinovia Dr J A Akpobi

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Chairman Secretary

Administrative Staff Mrs Pat E Orere Mrs Charity U Eboigbe Mr Monday Elaho

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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INTERNATIONAL ADVISORY COMMITTEE / COMITÉ CONSULTATIVE INTERNATIONAL Prof.Trevor Dean, University of Brimingham, UK Prof. Enrique Ares Gomez, University of Vigo, Spain Prof. Babs Oyeneyin, Robert Gordon University, UK Prof. Chimay Anumba, Loughborough University, UK Prof. Georgios Petropoulos, University of Thessaly, Greece Prof. James Momoh, Howard University, USA Prof. Emmanuel S. Eneyo, Southern Illionois University, U.S.A Prof. Kwadwo Osseo - Asare, The Pennsylvania State University, U.S.A Prof. Attahiru Alfa, University of Manitoba, Canada. Prof. Akpofure Taigbenu, University of the Witwatersrand, South Africa. Prof. M. T. Oladiran, University of Botswana, Botswana Prof. G. O. Anderson, University of Botswana, Botswana Prof. Opok Obok, University of Botswana, Botswana Prof. Yezouma Coulibaly, Burkina Faso Dr. G. E. Nkeng, Ecole Nationale Superieure, Cameroun Dr. G.S. Kumaran, Kigali Institute of Science & Technology, Rwanda Dr. G. Mwithiga, Botswana College of Agriculture, Botswana Dr. S. Madougou, Universite Abdou Moumouni, Niger. Dr. Ahmadu Barrie, University of Sierra Leone, Sierra Leone Prof. Godfrey Onwubolu, University of the South Pacific, Fiji. Prof. A. A. Aderoba, Federal University of Technology, Akure, Nigeria Prof. A. O. Inegbenebor, University of Maduguri, Nigeria. Prof. A. E. Oluleye, University of Ibadan, Nigeria Prof. M. O. Faborode, Obafemi Awolowo University, Nigeria Prof. Funso Falade, University of Lagos, Nigeria Prof. S. T. Wara, Igbinedion University, Nigeria Dr. I. I. Nnadi, first Medical and sterile Products Ltd, Nigeria Dr. E.J.S. Uujamhan, Oska-Jo & Partners, Benin City, Nigeria Dr. O. W. Uzebu, Chis-Epas Consults, Nigeria

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

PROGRAMME

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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PROGRAMME Monday 14 April 2008

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Arrival/Registration

Opening Session 8.00am – 10.00am 10.00am – 10.05am 10.05am – 10.10am

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10.10am – 10.20am

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10.20am – 11.20am

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11.20am – 11.50am 11.50am – 12.15pm

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(Venue: Akin Deko Auditorium) Registration Welcome of Participants Chairman’s Opening Address by Professor Emmanuel A.C. Nwanze Vice- Chancellor, University of Benin Goodwill message by Guests of Honour, Prof. A.S Sambo, DG/CEO, Energy Commission of Nigeria, Abuja and Prof. O O Adewoye, DG/CEO National Agency for Science & Engineering Infrastructure (NASENI), Abuja. Guest Lecture on Responsive Production Systems and Roles that Robots can Play by Professor Richard Weston, Head of Manufacturing Systems Integration (MSI) Research Institute, Loughborough University, Leicestershire, UK. Discussion Tea Break

Technical Sessions 12.15pm – 2.15pm (12.15pm – 1.45pm) (1.45pm – 2.15pm) 2.15 pm – 3.15 pm

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Venue (Faculty of Engineering) Technical Sessions 1A, 1B and 1C Paper Presentation Discussion Lunch

3.15pm – 5.15pm (3.15pm – 4.45pm) 4.45pm – 5.15pm) 5.15pm – 5.40pm

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Technical Sessions 2A, 2B and 2C Paper Presentation Discussion Tea Break

5.40pm – 7.40pm (5.40pm – 7.10pm) (7.10pm – 7.40pm) 7.40pm – 8.40pm

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Technical Sessions 3A, 3B and 3C Paper Presentation Discussion Dinner

Wednesday 16 April 2008 8.00am – 9.00am 9.00am – 11.00am (9.00am – 10.30am) (10.30am – 11.00am) 11.00am – 11.25am

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Registration continues Technical Sessions 4A, 4B and 4C Paper Presentation Discussion Tea Break

11.25am – 1.25pm (11.25am – 12.55pm) (12.55pm – 1.25pm) 1.25 pm – 2.25 p,m

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Technical Sessions 5A, 5B and 5C Paper Presentation Discussion Lunch

2.25pm – 4.25pm

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Technical Sessions 6A, 6B and 6C

Tuesday 15 April 2008

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria (2.25pm – 3.55pm) 3.55pm – 4.25pm) 4.25pm – 4.40pm

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Paper Presentation Discussion Tea Break

4.40pm – 6.40pm (4.40pm – 6.10pm) (6.10pm – 6.40pm) 6.40pm – 7.40pm

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Technical Sessions 7A, 7B and 7C Paper Presentation Discussion Dinner

Thursday 17 April 2008 8.00am – 10.00am (8.00am – 9.30am) (9.30am – 10.00am) 10.00am – 10.25am

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Technical Sessions 8A, 8B and 8C Paper Presentation Discussion Tea Break

10.25am – 12.25pm (10.25am – 11.55am) (11.55am – 12.25pm) 12.25pm – 12.40pm 12.40pm – 1.40pm 1.40pm – 4.40pm 4.40pm – 6.00pm 6.00pm – 8.00pm

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Technical Sessions 9A, 9B and 9C Paper Presentation Discussion Tea Break Closing Industrial Visit/Lunch Break Dinner/Gala Night (Venue: Banquet Hall)

Friday, 18 April, 2008 10.00 am-12.00 noon

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Interactive Session with Guest Speaker (Faculty of Engineering Board Room)

Venues for Technical Sessions Session A - Faculty of Engineering Board Room Session B - Chemical Engineering Auditorium Session C - Chemical Engineering Seminar Room

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 1A: Capacity Building in Engineering R & D: 15 April, 2008 (12.15 pm – 2.15 pm) Session Chair: Prof. O O Adewoye, DG / CEO, National Agency for Science & Engineering Infrastructure (NASENI), Co-Chair: Dr. A C Igboanugo, HOD Production Engineering, University of Benin Rapporteurs: Dr. S O Osuji / Dr. N. P. Orobor, University of Benin ICERD08002

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Designing the Spatial Requirements of a new facility for the Faculty of Engineering by T Oladiran (Faculty of Engineering and Technology, University of Botswana, P/Bag 0061, Gaborone, Botswana. [email protected]), and J. Foster, Carlisle College, Victoria Place, Carlisle, Cumbria, UK. Experiential learning centre for electronic Engineering Students through partnerships and collaboration S J Jacobs and F A O Otieno, Faculty of Engineering and the Built Environment, Tshwane University of Technology, South Africa. [email protected]; [email protected] Innovative developments in soil dynamics research facility: the FUTA experience by S I Manuwa, O C Ademosun, A S Ogunlowo and L A S Agbetoye, Dept. of Agricultural Engineering, Federal University of technology, Akure, Nigeria [email protected] Linking universities with industry: a key issue for sustainable development by Arezki Benfdila, LMPDS, Faculty of Electrical Engineering and Computer Science, The University M. Mammeri Tizi-Ouzou, Algeria and ICTP, Trieste, Italy [email protected]; [email protected] Effective intra-campus transportation systems by A.T. Layeni and A.A. Adeala, Dept. of Mechanical Engineering, Olabisi Onabanjo University, Ago-Iwoye, Ibogun Campus, Ogun State, Nigeria. E-mail: [email protected] Learning and teaching methods in engineering educational by S. Emakpor and J. Enomate, School of Engineering, Delta State Polytechnic, Otefe-Oghara, Delta State, Nigeria. E-mail: [email protected]. Engineering solutions for rural Africa: A case study of the impact of engineering research on the socio-economic development of rural Africa by S.G. Agong, Deputy Vice – Chancellor (Planning, Research and Extension Services), Maseno University, P.O. Box 333-40105, Maseno, Kenya. E-mail: [email protected] Adaptive research: an approach for fast optimal response for the transition of new technologies in the South of Saharan Sub-Region of Africa by Sambwa Adoko, Energy Consultant (Renewable Energy), Asa-Lambda Technology Ltd, 9 Akpakpava Road, Benin City, Nigeria. E-mail: [email protected]. A blind spot in structural engineering education with special reference to slope deflection methods of structural analysis by B.O. Adinna a A.A. Ezewamma a and V.M. Nwokike b a Faculty of Engineering Nnamdi Azikiwe University, Awka, bFaculty of Engineering, Anambra State University, Uli, Nigeria e-mail: [email protected]. Comparative analysis of manufacturing strategy of industrializing economies and Nigeria by E.O. Ezugwu and I.O. Abdulmalik. Machining Research Centre, Faculty of Engineering, Science and the Built Environment, London South Bank University, 103 Borough Road, SE1 OAA, United Kingdom. E-MAIL: [email protected].

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 1B: RENEWABLE ENERGY I: 15 April, 2008 (12.15 pm – 2.15 pm) Session Chair: Prof A S Sambo, DG/CEO, Energy Commission of Nigeria, Abuja Co-Chair: Dr. Senthil Kumaran, Kicali Institute of Science & Tech., Rwanda Rapporteurs: D I Igbinomwanhia/Emeka Amalu, University of Benin ICERD08005

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Smart Conditioning of the output characteristics of a photo voltaic position sensor using a feed forward neural network system by J T Agee, T T Tumane, M. Shedden and M Jeffrey, Dept. of Electrical Engineering, University of Botswana, P. Bag 0061, Gaborone, Botswana [email protected] Improving the efficiency of solar cells using quantum dots by S Y Mensah, N G Mensah, J A Yankey and F K A Allotey [email protected] Development of low cost solar illumination system for household by A.S. Adavbiele ( Dept. of mechanical engineering)and J.B. Erua (Dept. of Electrical/Electronic Engineering), Ambrose Alli University, Ekpoma, Edo State, Nigeria., [email protected], [email protected] The effect of turbidity of absorbing spherical dust particles on the thermal performance of a CPC solar water heater by H. Dan-Dakouta Dept. of Mechanical/Production Engineering, Abubakar Tafawa Balewa University, Bauchi, Nigeria (e-mail: [email protected]), and A.A. Asere, Dept. of Mechanical Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria Analysis of fish fillet drying rates under three solar energy drying systems by G. Mwithiga (Dept. of Agricultural Engineering and Land Planning, Botswana College of Agriculture, Private Bag 0027, Gaborone, Botswana. E-mail: [email protected]) and S.G. Mwangi (Dept. of Biomechanical and Environmental Engineering, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000, Nairobi, Kenya). Optimal utilization of solar cells: design and implementation of sun tracking solar cell array system by E.U. Ubeku and S.O. Igbinovia, Dept. of Civil Engineering, University of Benin, Benin City, Nigeria, e-mail: [email protected] Optimum seeking position control of solar collectors by A.S. Kadalla (email:[email protected], Tel.: +2348034378394), S.I. Lassa (e-mail: [email protected]. Tel: +2348053348922) and O.N. Zara (e-mail: [email protected] Tel.: +2348036059815), Dept. of Electrical/Electronic Engineering, Federal University of Technology, Yola, Nigeria. Development of a photovoltaic powered forced connection solar dryer by A.O. Adelaja, B.Y. Ogunmola, P.O. Akolade and A.O. Adejumobi, Dept. of Mechanical Engineering, University of Lagos, Lagos, Nigeria. E-mail: [email protected] Tel.: +2348068123861. Solar technology R &D innovations at CBSS by J.O. Inwelegbu and P.N. Okeke, Centre for Basic Space Science, University of Nigeria, Nsukka, Nigeria. E-mail: [email protected]. Solar hydrogen energy system – Principle, applications and market by G. Ofualagba, M. Jemerigbe and M. Ofualagba, Dept. of Electrical and Electronics Engineering, Delta State Polytechnic, Otefe. Oghara, Delta State, Nigeria. E-mail: [email protected].

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 1C: MATERIALS AND PROCESSING I: 15 April, 2008 (12.15pm– 2.15 pm) Session Chair: Engr. Aminu Jalah, DG/CEO National Automotive Council, Abuja Co-Chair: Dr. C M Mbohwa, University of Johannesburg, South Africa Rapporteurs: Dr. J A Akpobi/Dr. E A Aisien, University of Benin, Nigeria ICERD08028

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Corrosion behaviour of aluminum 1017 in domestic food-cooking environment by S.A. Balogun, D.E. Esezobor and S.O. Adeosun, Dept. of Metallurgical and Materials Engineering, University of Lagos, Akoka, Yaba, Lagos, [email protected], [email protected] Development of particulate reinforced aluminium metal matrix composite by S.A. Balogun, D.E. Esezobor, S.O. Adeosun, A.M. Oladoye and L.D. Osoba, Dept. of Metallurgical and Materials Engineering, University of Lagos, Akoka, Yaba, Lagos, Nigeria. [email protected], [email protected] Effects of quenching variables on the fracture toughness of 0.3C hypo-eutectoid plain carbon steel by D.E. Esezobor, M.O.H. Amuda, B.U. Amaechi and G.I. Lawal, Dept. of Metallurgical and Materials Engineering, University of Lagos, Akoka, Yaba, Lagos, Nigeria. [email protected], [email protected] Pyrometallurgical extraction of lead from galeus PbS using direct reduction process by J.U. Odo , S.O. Obiorah, Dept. of Metallurgical and Materials Engineering, Nnamdi Azikiwe University, Awka, Anambra State and E.M. Ameh (Dept. Metallurgical and Materials engineering, Enugu state University of Science and Technology, Enugu), Nigeria. [email protected] Effects of selected media on corrosion behaviour of mild steel by B. Kareem, [email protected], [email protected] Comparative corrosion characteristics of ductile grey irons and mild steel in different soils by A.F. Ayeni (National Metallurgical Development Centre, P.M.B. 2116, Jos, Nigeria. E-mail: [email protected]), V.S. Aigbodion (Dept. of Metallurgical Engineering, Ahmadu Bello University, Zaria. E-mail: [email protected]) and J. Agunsoye (Dept. of Metallurgical & Materials Engineering, University of Lagos, Lagos, Nigeria. E-mail: [email protected]) Evaluating micro structural and hardness variations in time dependent multipass welded mild steel by M.O.H. Anuda, K. Ojemeni, A.M. Oladoye, J.O. Agusoye and O.W. Subair. E-mail: [email protected], [email protected] Effects of initial grain size on recrystallization and mechanical properties of steel by A. Adebayo and I.O. Ogunleye, Dept. of Mechanical Engineering, University of Ado-Ekiti, Ekiti State, Nigeria. E-mail: [email protected]. Effects of heat treatment on the mechanical properties of mild steel by I.O. Ogunleye and A. Adebayo, Dept. of Mechanical Engineering, University of Ado-Ekiti, Ekiti State, Nigeria. E-mail: [email protected]. Improvement of microstructure and magnetic properties of Fe-Al Composite by mechanical alloying by Z. Hamlati, Departement d’Aeronautique, Department des Sciences de l’ingenieur, Universite Saad Dahleb (USTB), BP 270 Route de soumaa, Blida, Algerie), S. Bergheul and Mr. Azzaz (Laboratoire de science et genie des materiaux (USTHB), BP 32, Bab Ezzouar, Algerie) e-mail: [email protected]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 2A: RENEWABLE ENERGY II: 15 April, 2008 (3.15 pm – 5.15 p.m.) Session Chair: Dr. F C Obi, Director Centre for Adaptation of Technology, Awka, Nigeria Co-Chair: Dr. John Azee, University of Botswana, Botswana Rapporteurs: Dr A I Igbafe/H A P Audu, University of Benin ICERD08019

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The role of renewable energy in the electricity industry in Zimbabwe by Charles Mbohwa (Dept. of Quality and Operations Management, University of Johannesburg, Auckland Park Bunting Road Campus, P.O. Box 17011, Doorfontein 2028, Johannesburg, South Africa.([email protected]) and Bukhosi Siso, Zimbabwe Electricity Distribution Company, P.O. Box 377, Harare, Zimbabwe ([email protected]) A framework for readiness assessment of renewable energy provision in developing countries by S.O. Ojo ([email protected]) and M.T. Oladiran ([email protected]), University of Botswana, P/Bag 0022, Gaborone, Botswana Biogas production from cassava waste by J.A. Kehinde (Dept. of Chemical Engineering), S.J. Ojolo (Dept. of Mechanical Engineering) and B.E. Ebiobi, University of Lagos, Nigeria. E-mail: [email protected] Application of wind and small hydro energy sources for rural electric power supply in Nigeria by Boyi Jimoh (e-mail: [email protected]), Yusuf Jibril (e-mail: [email protected] and Muazu (e-mail: [email protected]), Dept. of electrical Engineering, Ahmadu Bellow University, Zaria, Nigeria. Sustaining the rural energy demand through biogas technology by J.O. Aribisala and T. Omotoso, Dept. of Civil Engineering, University of Ado-Ekiti, Ado-Ekiti, Nigeria. Email: [email protected], [email protected] Development of an energy – efficient solid fuel for maximum emission-reduction and enhanced heating capability in fired heaters by A.I. Igbafe, Dept. of Chemical Engineering, University of Benin, Benin City. E-mail: [email protected] Assessment of hydraulic performances of drainage channels in UNAAB Campus by G.A. Bolaji, Dept. of civil Engineering, University of Agriculture, Abeokuta, Nigeria. Email: Combating global warming in Nigeria by O.A. Ogugbenro and F.C. Obi, Dept. of Solar Applications, Electronics Development Institute, (ELDI), Awka (NASENI), Federal Ministry of Science & Technology, Nigeria. E-mail: [email protected] New technologies for rural lighting in developing countries by G. Ofualagba, M. Jemerigbe and M. Ofualagba, Dept of Electrical and Electronics Engineering, Delta State Polytechnic, Otefe-Oghara, Delta State, Nigeria. E-mail: [email protected].

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 2B: MATERIALS AND PROCESSING II: 15th April 2008 (3.15 pm – 5.15 pm) Session Chair: Prof R O Ebewele, University of Benin Co-Chair: D. S B Adejuyigbe, Federal University of Technology, Akure, Nigeria Rapporteurs: Dr. S O Onohaebi/G O Ariavie, University of Benin ICERD08052

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Development and preservation of adhesives using cassava starch, by C. E. Akhabue Department of Chemical Engineering, University of Benin, Nigeria, Phone: 234 803 355 3215 Design of compatibilizing interfacial polymer layers using a macronitiator by M.K. Oduola, Dept. of Chemical Engineering, University of Port Harcourt, Port Harcourt, Nigeria. E-mail: [email protected], Tel: +2348038910889, +23451033338 Degradation of polypropylene using acid – treated clay as catalyst by M.A. Olutoye, Dept. of Chemical Engineering, Federal University of Technology, Minna, Nigeria. Email: [email protected] Network structures, flexibility and stability in thermal and chemical environments of polyurethane prepared from rubber seed oil by F.E. Okieimen (1Dept. of Chemistry & Centre for Biomaterials Research, University of Benin, Benin City, Nigeria. E-mail: [email protected], I.O. Bakare1 and C. Pavithran (Polymer Science Division, Regional Research Laboratory, CSIR, Trivandrum, India) Studies in the utilization of biobased additives as thermal stabilizer for plasticized PVC by F.E. Okieimen (Dept. of Chemistry and Centre for Biomaterials Research, University of Benin, Benin City, Nigeria. E-mail: [email protected]), T.O. Egbuchunam (Dept. of Chemistry, college of Education, Warri, Nigeria) and D. Balkose (Dept. of Chemical Engineering, Izmir Institute of Technology, Urla-Izmir, Turkey). Characterization and potentials of natural fibres for industrial application by J.U. Odo and C.U. Atuanya, Dept. of metallurgical and Materials Engineering, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria. E-mail: [email protected]. Effect of particle sizes on the reinforcing properties of a locally sourced filler by E.O. Aluyor (Dept. of Chemical Engineering) University of Benin, Benin City, Nigeria. E-mail: [email protected]) and O.I. Oboh (Dept. of Chemical Engineering, University of Uyo, Uyo, Nigeria). The effect of processing techniques on the mechanical properties of rice husk polypropylene composite by B I Ugheije, M R Joshua and R N Ufodi, University of Abuja, Nigeria. E-mail: [email protected] Deposition of Zinc sulphide (ZnS) thin films in a polymer matrix by F.I. Ezema, E.N. Okongwu, V.C. George, A.I. Asiegbe, A.B.C. Ekwealor, P.U. Asogwu and R.U. Osuji, Dept. of Physics and Astronomy, University of Nigeria, Nsukka, Nigeria. Email: [email protected] La jacithe d’eau dans: l’epuration des eaux usees, la fabrication des composites, et des spirales anti-moustiques by Laouali M. Sani, Idder Tahar and Ousmane Zaki, Dept. of Chemistry, Faculty of Science, University of Niamey, Niger. E-mail: [email protected]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 2C: ENERGY AND POWER: 15th April 2008 (3.15 pm – 5.15 pm) Session Chair: Prof Emmanuel Emeyo, Southern Illinois University, USA Co-Chair:: Dr U J Udosen, University of Benin Rapporteurs: Engr. J O Osarenmwinda/PE Anmiolemhen ICERD08042 ICERD08061

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Power quality assessment in a distribution network by B.A. Adegboye Dept. of Electrical Engineering, Ahmadu Bello University, Zaria, Nigeria e-mail: [email protected] Electrical power distribution and security: an alternative option by G.I. Efenedo, (Dept. of Computer Science) and A. Akponah (Dept. of Electrical/Electronic Engineering), Delta State Polytechnic, Otefe-Oghara, Delta State, Nigeria. e-mail: [email protected] Few major feeder pillar faults identification using Pareto Analysis by E.A. Ogujor, E.U. Ubeku and P.T. Aikhoje Dept. of Electrical/Electronic Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected]. Lightning phenomenon and its effects on power systems by I.A. Adejumobi, Dept. of Electrical/Electronic Engineering, University of Agriculture, Abeokuta, Ogun State, Nigeria. E-mail: [email protected] Analysis of generating capacity dynamics of the Nigerian power system between 1963 and 2020 by A.O. Melodi, Dept. of Electrical/Electronic Engineering, Federal University of Technology, Akure, Nigeria. e-mail: [email protected] Power quality assessment in a distribution network by B.A. Adegboye, Dept. of Electrical Engineering, Ahmadu Bello University, Zana, Nigeria. e-mail: [email protected] Dielectric strength and breakdown voltage with respect to transformer insulating oil by I.A. Adejumobi, Dept. of Electrical/Electronic Engineering, University of Agriculture, Abeokuta, Nigeria. E-mail: [email protected] Natural-gas engine generator in Nigerian energy mix by E.G. Sadjere and E.N. Ohwovorole, Dept. of Mechanical Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected]. Measurement and verification of domestic energy efficiency by S.T. Wara 1,a, A. Aboyomi-Alli 1,b, and Afua K. Mohammed 2,c 1Product Development Energy Centre, Electrical and Computer Engineering Dept., Igbinedion University, Okada, Edo State, Nigeria. a [email protected], [email protected] An impact assessment of the Nigerian power Sector reforms by S.T. Wara, A. AbayomiAlli and N.D. Umo (contacts as in ICERD08229 (1,a and 1,b) Electricity network planning: The key to efficient and reliable power supply to consumers by S.O. Onohaebi and S.T. Apeh, Dept. of Electrical/Electronic Engineering, University of Benin, Nigeria

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 3A: MATERIALS AND PROCESSING III:15th April 2008 (5.40 pm – 7.40 pm) Session Chair: Prof T O K Audu, University of Benin Co-Chair: Dr. O D Nworgu, University of Benin Rapporteurs: Dr. C Izinyon/Dr C Owabor, University of Benun ICERD08069

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Physical and Chemical analysis of some Nigerian Gypsum minerals for application in Manufacturing, Construction and Allied Industries by P.S.A. Irabor (Federal Institute of Industrial Research, Oshodi (FIIRO), Lagos, Nigeria, e-mail: [email protected], tel: +2348023415053), S.O. Jimo (1Dept. of Materials and Production Engineering, Ambrose Alli University, Ekpoma, Edo State, Nigeria, E-mail: [email protected]), O.J. Omowunmi1 and B.S.O. Ighalo2 (e-mail: [email protected], Tel: +2348039512648 e-mail:[email protected] Effect of base material on the pore size distribution and surface area of activated carbon by O.O. Ojo, Dept. of Civil Engineering, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria. e-mail: [email protected] Assessment of the effects of acetic acid-hexane ratio on the physio-chemical properties of Itura crepitan by I. R. Ilaboya, Dept. of Chemiccal Engering, Igbinedion University, Okada, Edo Sstate, Nigeria. E-mail [email protected]. Adsorption of zinc from aqueous solution of zinc nitrate using granular activated carbon prepared from palm nut chaff (pnc) I. R. Ilaboya, Dept. of Chemiccal Engering, Igbinedion University, Okada, Edo Sstate, Nigeria. E-mail [email protected]. Characterization of Ogulogu-Olo clay deposit for industrial applications by S.O. Obiorah, J.U. Odo and C.C. Daniel, Dept. of Metallurgical and Materials Engineering, Nnamdi Azikiwe University, Awka, Nigeria. email: [email protected]. Industrial potentials of a Nigeria clay deposit-Ogulogu-Ola by S.O. Obiorah, J.U. Odo and C.C. Daniel, Dept. of Metallurgical and Materials Engineering, Nnamdi Azikiwe University, Awka, Nigeria e-mail: [email protected] Permeability characteristics and classification of coal seams in Nigeria by B.M. Olaleye (1Dept. of Mining Engineering, Federal University of Technology, Akure, Nigeria) Email: [email protected]), O.O. Onyemaobi (2Dept. of Metallutgical & Materials Engineering, Federal University of Technology, Owerri, Nigeria) and J.M.Akande1 Mathematical modeling of super critical carbon dioxide extraction of essential oil from caraway seeds by G.B. Olowojoba (e-mail: [email protected]:uk) and S.E. Ogbeide (e-mail: [email protected]), Dept of Chemical Engineering, University of Benin, Benin City, Nigeria. The study of biogeoavailability of calcium in cement industry environments of North Eastern Zone of Nigeria by A.I. Inegbenebor, Dept. of Chemistry, Covenant University Canaan Land, Ota Ogun State, Nigeria. email: [email protected] Adoucissement des eaux dures par le phosphate monosodique by A.S. Manzola a, A. Mgaidi b and M. El Maaoui b a Laboratoire de Chimie Analytique et Minerale, Facute’ des sciences universite Abdou Moumouni, BP10662, Niamey, Niger, b Universite de Tunis. El Manar BP37 El Belvedere 102 Tunos, Tunisie. E-mail: : [email protected]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 3B: MATALWORKING PROCESSES 15th April 2008 (5.40 pm – 7.40 pm) Session Chair: Prof J C Nwachukwu, University of Benin Co-Chair: Dr. J U Okoli, University of Port Harcourt Rapporteurs: Dr E U Ubeku/B A Aburime, University of Benin ICERD08008

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Splattering of impinging liquid jet on a flat plate or pipe surface by G E Nkeng (Faculty of Science, University of Buea, P.O.Box 63, Buea, Cameroon or ENSTP, B.P. 510, Yaounde, Cameroon, [email protected]) and P F Nolan (Chemical Engineering Research Centre, School of Appled Science, South bank University, 103, Borough Road, London SE1 0AA, U.K. Anisotropic behaviour of deep drawn aluminum 1017 alloy using macroscopic tensile and cupping test by S.A. Balogun and D.E. Esezobor, Dept. of Metallurgical and Materials Engineering, University of Lagos, Akoka, Yaba, Lagos, Nigeria. [email protected], [email protected] Simulation of load during rod rolling of HC SS316 at low strain rates by P.O. Aiyedun (1Dept. of Mechanical Engineering, University of Agriculture, Abeokuta, Ogun State, Nigeria. E-mail: [email protected]), S.O. Igbudu (Dept. of Mechanical Engineering, Ambrose Alli University, Ekpoma, Edo State, Nigeria) and B.O. Bolaji1 Mean rolling temperature for steels hot flat rolled at low strain rates by P.O. Aiyedun and S.A. Aliu, Dept. of Mechanical Engineering, University of Agriculture, Abeokuta, Ogun State, Nigeria (e-mail: [email protected]) Specifics of chip formation during turning of titanium and its alloys by O.O. Awopetu, Dept. of Mechanical Engineering, Federal University of Technology, Akure, Nigeria. A new surface finish based criterion on machinability of materials in turning by G. Petropoulos, N. Hassiotis and G. Kasar lis [email protected] Effect of pass reduction on rolling parameters using reverse sandwich model integrated into the hot rolling Bland and Ford’s theory by O.J. Alamu and P.O. Aiyedun Dept. of Mechanical Engineering, University of Agriculture, P.M.B. 2240, Abeokuta, Nigeria. e-mail: [email protected]. Multi-objective optimization of some machining parameters in turning operation using Teguchi Method by I.M. Dagwa, Dept. of Mechanical Engineering, University of Abuja. E-mail: [email protected] Analysis of forging process by the weighted residual finite element method by John A. Akpobi and Christian O. Edobor, Dept. of Production Engineering, university of Benin, Benin City, Nigeria e-mail

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 3C: WATER ENGINEERINNG: 15th April 2008 (5.40 pm – 7.40 pm) Session Chair: Prof F E Okieimen, University of Benin Co-Chair:Dr S E Ogbeide, University of Benin Rapporteurs: M A Omoregie/M Chukwuma ICERD08007

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Water quality and occurrence of water-borne diseases in the Douala 4th District, Cameroon by Andrew A Ako (Hydrological research Centre (IRGM), BP 4110 Yaounde, Cameroon [email protected]), G E Nkeng (Ecole Nationale Superieure des Travaux Publics (ENSTP), BP 510, Yaounde, Cameroon) and G E E Takem (Hydrological Research Centre (IRGM), BP 4110, Yaounde, Cameroon) Domestic wastewater treatment with a vertical completely drained pilot scale constructed wetlad planted with corchorus diterius by Lacina Coulibaly (UFR-SGE 02 BP 801, Abidjan 02, Cote d’Ivore. [email protected]), Issiaka Savane and German Gourene Pretraitement des effluents d’une indusrie textile par un filtre a sable perfore lateralement a alimentation intermitente by L Coulibaly (UFR-SGE 02 BP 801, Abidjan 02, Cote d’Ivore. [email protected]), P O Tchehue et, I Savarie (Laboratoire de Geosciences et Environnement (LGE), UFR-Sciences et Gestion de l’Environnement, Universite d’Abobo-Adjame, 02 BP 801, Abidjan 02, Cote d’Ivore Bioremediation of refinery waste water using inorganic fertilizer (NPK 15: 15: 15) by K.O. Obahiagbon (Tel: +2348023361732) and C.E. Akhabue (Tel: +2348033553215), Dept. of Chemical Engineering, University of Benin, Benin City. E-mail: [email protected]) Bioremediation of crude oil contaminated water using Pseudomonas aeruginosa and inorganic fertilizer (NPK 15: 15: 15) by K.O. Obahiagbon (Tel: +2348023361732) and C.E. Akhabue (Tel: +2348033553215), Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected] Multi-parameter model for computing head loss development in deep bed (depth) filters used for production of potable water by O.E. Ekenta (Dept. of Civil Engineering, Namdi Azikiwe University, Awka, Nigeria. E-mail: [email protected]) and B.U. Anyata (Dept. of Civil Engineering, University of Benin, Benin City, Nigeria. Email:[email protected]). Drinking water quality monitoring in Ado-Ekiti and Environs, Nigeria by P.O. Folorunso – E-mail: [email protected] and Toyin Omotoso, Dept. of Civil Engineering, University of Ado-Ekiti, Ekiti State, Nigeria (e-mail: [email protected]) Evaluation Of Ogun State Water Supply Scheme in Abeokuta metropolis by D. Sulaimon, (Dept. of Mechanical Engineering) and A.O. Adesina (Dept. of Agricultural Engineering, Olabisi Onabanjo University, Ibogun Campus, Ogun State, Nigeria. Email: [email protected] The use of local materials in water disinfection by B.U. Anyata and V.E. Mgbemere, Dept. of Civil Engineering, University of Benin, Benin City, Nigeria. e-mail: [email protected] Use of hydraulic model for evaluating the fire flow capacity of Benin City urban water distribution network by O.C. Izinyon and B.U. Anyata, Dept. of Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 4A: MATERIALS AND PROCESSING IV:16th April 2008 (9.00 am –11.00 am) Session Chair: Prof A E Oluleye, University of Ibadan Co-Chair: Dr. A I Obanor, University of Benin Rapporteurs: S A Ike/O U Orie, University of Benin ICERD08004

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Medium optimization of spectrofburimentic determination of histamine in halieutic and derived product by using flourescamine as derivitizer by R Adamou (Universite Abdou Moumouni, Niamey, Niger. [email protected]), A Coly, S E Doubale,M L Salad k Ikhiri and A Tine Universite Cheikh Anta Diop, Dakar, Senegal [email protected] Fine-tuning of surface plasmon resource in AU-VO2 nanoplasmonics synthesiced byrf Inverted Cylindrical Manetron sputting by J B Kana Kana (Nanoscience and Nanotechnology Laboratories, Materials Research Group, iThemba LABS, P.O.Box 722, Somerset West 7129, South Africa or Dept. of Physics, University of Yaounde I, P.O.Box 812 Yaounde, Cameroon), J M Ndjaka (University of Yaounde I, P.O.Box 812 Yaounde, Cameroon), N Manyala (Dept. of Physics and Electronics, National University of Lesotho, p.O.Box Roma 180, Maseru, Lesotho), O Nemraoui (Dept. of physics, University of Zululand, Private Bag X1001, Kwadlangezwa, South Africa), A C Beye (African Laser centre, P.O.Box 395, Pretoria 0001, South Africa) and M. Maaza(Nanoscience and Nanotechnology Laboratories, Materials Research Group, iThemba LABS, P.O.Box 722, Somerset West 7129, South Africa) [email protected] Leaching of trace metals from two different size-grained soils by A Y Abdulfatah (Dept. of Civil and Building Engineering. [email protected]), A El-Hamalawi (Geomechanics, Dept. of Civil and Building Engineering. [email protected]) and A D Wheatley (Environmental Engineering, Dept. of Civil and Building Engineering. [email protected]), Loughborough University, UK Recent trends in laser industry and applications: Literature review by A. Niyibizi, Dept. of Physics, university of Nairobi, P.O.Box 30197, Nairobi, Kenya. [email protected] Glass manufacturing: modeling glass flow in pressing process by Tsegaye G. Ayele, Dept. of Mathematics, Addis Ababa University, Ethiopia. [email protected] Survey of the development in automotive materials: Peugeot Model as a case study by B. Kareem, S.B. Adejuyigbe and S.P. Ayodeji, Dept. of mechanical engineering, Federal University of Technology, Akure, Ondo State, Nigeria. [email protected] A comparative analysis of phosphate and zeolite-based laundry detergents by M.D. Yahaya and C.A. Takaya, Dept. of Chemical Engineering, Federal University of Technology, Minna, Niger State, Nigeria. e-mail: [email protected] Thermochemical conversion of cashew nut shell into fuel and chemical additives by B.O. Ogunsina (a Agric Engineering Dept., Obafemi Awolowo University, Ile-Ife, Nigeria), S.J. Ojolo (Mechanical Engineering Dept., University of Lagos, Lagos, Nigeria), M. Falade a and I.Imoudu Email: [email protected] Switching behaviour in Ag/pbSnS3/Al metal-semiconductor-metal (MSM) thin film structures by S.O. Azi and E. Aghemenloh, Dept. of Physics, University of Benin, Benin City, Nigeria. E-mail: [email protected]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 4B: TOOLS, DIES AND MOULDS: 15th April 2008 (9.00 am – 11.00 am) Session Chair: Prof O E Charles-Owabo, University of Ibadan Co-Chair: Dr. O E Alutu, University of Benin Rapporteurs:E O Aluyor/S A Aliu, University of Benin ICERD08135

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Risering of a four-cavity die production mould by convectional method by L.B. Zhengwuvi (Dept. of Mechanical Engineering, Federal University of Technology. P.M.B. 2076, Yola, Nigeria) e-mail: [email protected]. Tel: +2348080392955 Computer aided design and drafting (CADD) modeling for gas welding process by S.B. Adejuyigbe and A.A. Adekunle, Dept. of Mechanical Engineering, Federal University of Technology, Akure, Nigeria. e-mail: [email protected] Computer aided model for casting aluminum using die-casting by S.B. Adejuyigbe, P.B. Mogaji and O.M.T. Dada, Dept. of Mechanical Engineering, Federal University of Technology, Akure, Nigeria. e-mail: Computerized design approach to a sub-press mould for composite materials manufacture by I.M. Dagwa (Dept. of Mechanical Engineering, University of Abuja, Nigeria. e-mail: [email protected]) and A.O.A. Ibhadode (Dept. of Production Engineering, University of Benin, Benin City. E-mail: [email protected]. Production of permanent moulds for casting linkage mechanisms of an 80cc motorcycle engine combustion compartment by E.A. Amalu and A.O.A. Ibhadode, Dept. of Production Engineering, University of Benin, Nigeria. Computer-aided design (CAD) of a completely closed cavity die forging die by the expansion method by P.E. Amiolemhen and A.O.A. Ibhadode, Dept. of Production Engineering, University of Benin, Nigeria. E-mail: The effect of die container compounding on product accuracy in completely closed cavity die forging by A.O.A. Ibhadode, and G.E. Aibangbee (Dept. of Production Engineering, university of Benin, Nigeria). E-mail: Quality characteristics of basic hand tools sold in Nigeria by F.A. Oyawale and M.A. Ogunmolati, Industrial & Production Engineering Dept., University of Ibadan, Ibadan, Nigeria e-mail: [email protected].

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 4C: WASTE TECHNOLOGY: 16th April 2008 (9.00 am – 11.00 am) Session Chair: Prof P O Aiyedun, University of Agriculture, Abeokuta Co-Chair: Dr E S Adewole, University of Benin Rapporteurs: A A Adeniji/P E Amiolemhen, University of Benin ICERD08276

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Applications of recycled rubber from scrap tyres in oil pollution control and road durability improvement by R.O. Ebewele, F.A. Aisien, Dept. of Chemical Engineering, University of Benin and F.K. Hymore (Dept. of Chemical Engineering, Covenant University, Ota, Ogun State, Nigeria Development of useful products from oil palm trunk waste particles by G.F. Aibangbee (Nigerian Institute for Oil Palm Research, Benin City. [email protected]) and A.O.A. Ibhadode (Dept. of production Engineering, University of Benin, Nigeria. [email protected]) Fuzzy based solid waste management method by O.O. Ojo (Dept. of Civil Engineering, Rugus Giwa Polytechnic, Owo, Ondo State, Nigeria. e-mail: [email protected]) and B.U. Anyata, (Civil Engineering Dept., University of Benin, Benin City, Nigeria. Investigation into the effects of paraffin wax on the properties of sawdust based table mat by same author I.R. Ilaboya, Dept. of chemical engineering, Igbinedion University, Okada, Edo State, Nigeria. E-mail: [email protected] tel: +2348038027260 Removal of chromate from tanning waste by ion exchange by G. Kabir (Abubakar Tafawa Balewa University, Bauchi, Nigeria) and S.E. Ogbeide (Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected]). Indoor smoke emissions from direct-fires in households Midwestern Nigeria by A.I. Igbafe, Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. E-mail:[email protected] Bio-treatment of crude oil polluted using mixed microbial populations of P. aureginosa, Penicillin notatum by .E. Coli and Aspergillus Niger by K.O. Obahiagbon and C.N. Owabor, Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected];[email protected] Assessing the rate of remediation f polycyclic aromatic hydrocarbon contaminated soil by using redox parameters by C.N. Owabor and K.O. Obahiagbon, Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. Batch treatment of palm oil mill effluent by Aisien F.A., Ojarikre A.A. and Aisien E.T. Dept. of Chemical Engineering, University of Benin, Benin City. Toxicity Assessment of Crude Oil Contaminated Soil in Niger Delta Areas by Aisien, F.A., Chiadikobi, J.C. and Aisien E.T. Dept. of Chemical Engineering, University of Benin, Benin City Solid Waste Crisis in Nigeria: A case study of the constraint to effective Private Sector Participation (PSP) on Solid Waste Management in Lagos metropolis by D.I. Igbinomwanhia and J. Olanikpekun, Dept. of Mechanical Engineering, University of Benin, Nigeria. E-mail: digbinommwanhiayahoo.com.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 5A:FOOD AND AGRICULTURAL TECHNOLOGY I: 16th April 2008 (11.25 am –1.25 pm)

Session Chair: Prof G C Ovuworie, University of Benin Co-Chair: Dr S O O Badeso, Forestry Research Institute of Nigeria, Ibadan Rapporteurs: K O Obahiagbon/Ngozi Ihimekpen, University of Benin ICERD08043

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Mathematical modeling of drying of Nigerian Cassava varieties in thin layers by Taiwo Ademiluyi, Dept. of Chemical/Petroleum Engineering, Rivers State University of Science & Technology, Port Harcourt, Nigeria, e-mail: [email protected], tel:+2348055339435, Koyejo Oduola, Dept. of Chemical Engineering, University of Port Harcourt, Port Harcourt, Nigeria, e-mail: [email protected]. Tel: +2348038910889, +23451033338 and Joy Eke (Dept. of Food Science & Technology, Rivers State University of Science & Technology, Port Harcourt. Email: [email protected]) Effect of mashing and controlled fermentation on the sensory and chemical properties of burukutu by K.A. Adesina, Dept. of Food Science & Technology, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria. E-mail: [email protected] Antioxidant activity of cabbage star leaf extract on crude palm kernel oil by J.O. Arawande, Dept. of Science Laboratory Technology, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria. E-mail: [email protected] Dehydrated cassava chips utilization in starch and garri production by A.V. Ikujenlola and S.V. Omosuli, Dept. of Food Science & Technology, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria. E-mail: [email protected] Effects of storage in high density polyethylene bag on quality parameters of fresh cassava roots and fufu flour by S.V. Omosuli and A.V. Ikujenlola, Dept. of Food Science & Technology, Rufus Giwa Polytechnic, Ondo, Ondo State, Nigeria. E-mail: [email protected] Some moisture dependent physical properties of maize seed by O.P. Sobukola, V.I. Onwuka, A.M. Oluyinka and S.O. Awonrin Dept. of Food Science & Technology, University of Agriculture, P.M.B. 2240, Abeokuta, Nigeria. E-mail: [email protected] Effects of quantity of salt and drying on the quality of locust beans by O. Awogbemi and I.O. Ogunleye, P.O.Box 1940, Ado-Ekiti, Ekiti State, Nigeria. e-mail: [email protected], [email protected] tel:+2348067430191 Influence of process parameters on moisture diffusivity of mud catfish (Clarius gariepinas) by Taiwo O. Olurin (1Dept. of Food Technology, Bells University, Ota, Nigeria) Emmanuel S. Abbo (Dept of Food Technology, Kaduna Polytechnic, Kaduna, Nigeria) Aminnat O. Adelekan1 and Solomon A. Osofero (Agriculture and Fishery Unit, Bells University of Technology, Ota, Nigeria. E-mail: [email protected]. The Effects of Linear Alkyl Benzene Sulfonate Detergent on the Activity of Cassava Fermenting Enzyme by Aisien E.T., Elaho, E.R. and Aisien F.A., Dept. of Chemical Engineering, University of Benin, Benin City.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 5B: MACHINES AND EQUIPMENT I: 16th April 2008 (11.25 am –1.25 pm) Session Chair: Prof J O Asalor, University of Benin Co-Chair: Dr. (Mrs.) Dayo Inegbenebor, Covenant University, Ota Rapporteurs: Dr E A Ogujor/A Ugherughe, University of Benin ICERD08024

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Performance evaluation of palm waste screw press briquette moulding machine by C.O. Ilechie, G.F. Aibangbee and S.R. Ogblechi, Nigerian Institute for Oil Palm Research (NIFOR), Benin City, Nigeria. [email protected] Design and preliminary testing of a stratified down-draught gasifier by H. Dandakouta, A.M. Hassan, M. Ahmed and M.H. Ibrahim, Dept. of Mechanical/Production Engineering, Abubakar Tafawa Balewa University, P.M.B. 0248, Bauchi, Nigeria. Email: [email protected] Construction and installation of a large radio telescope in Nigeria by P.N. Okeke1 and B.I. Okere2, Centre for Basic Space Science, University of Nigeria, Nsukka, Nigeria. (Email (1) [email protected] (2) [email protected]) Performance evaluation of a manually operated agricultural impact cutting machine by F.A. Maunde (1Dept. of Agricultural Engineering, Federal University of Technology, Yola Adamawa State, Nigeria and I.N. Itodo (Dept. of Agricultural Engineering, University of Agriculture, P.M.B. 2373, Makurdi, Benue State, Nigeria: e-mail: [email protected]) nd T.I. Ibrahim1 (e-mail: [email protected]) Development of software package in designing chain drives as engineering transmission element by M.B. Adeyemi Dept. of Mechanical Engineering, University of Ilorin, Ilorin, Kwara State, Nigeria and M.K. Adeyeri, Dept. of Mechanical Engineering, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria. e-mail: [email protected] Flapper feed device for increased productivity of cassava grater by J.U. Okoli, Dept. of Mechanical Engineering, University of Port Harcourt, Port Harcourt, Nigeria. e-mail: [email protected]. Design of a plastic tooth pick producing machine by P.O. Ojo, Dept. of Mechanical Engineering, Rufus Giwa Polythecnic, Owo, Ondo State, Nigeria. e-mail: [email protected]. Tel: +2348085672561 Development of auxiliary equipment for improved reliability of tyre removal by S.B. Adejuyigbe and T.S. Dafe, Dept. of Mechanical Engineering, Federal University of Technology, Akure, Nigeria. e-mail: High order cfd virtual flowlab for the laval nozzle design by A.S. Adavbiele, Dept. of Mechanical Engineering, Ambrose Alli University, Ekpoma, Nigeria. e-mail: [email protected] Design and construction of a melon shelling and separating machine by S.O. Jimoh, M.E. Iribhogbe and E.P. Ohiosimusu, Dept. of Materials & Production Engineering, Ambrose Alli University, Ekpoma, Nigeria. E-mail: [email protected]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

Technical Session 5C:

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ELECTRICAL/ELECTRONIC EQUIPMENT: 16th April 2008 (11.25 am –1.25 pm)

Session Chair: Prof M T Oladiran, University of Botswana, Botswana Co-Chair: Prof S T Wara, Igbinedioon University, Okada, Nigeria Rapporteurs:O R Edookppia/J I Achebo, University of Benin ICERD08057

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Application of particle swarm optimization approach to optimal tuning of load frequency controller by G.A. Bakare, Dept. of Electrical/Electronic Engineering, Abubakar Tafawa Balewa University, Bauchi (e-mail: [email protected]) and M. Kunduli, Dept. of Electrical/Electronic Engineering, University of Maiduguri, Maiduguri, Nigeria (e-mail: [email protected]) Differential evolution base optimal tuning of load frequency controller by A.K. Inyanda (Sheda Science and Technology Complex, Gamma Irradiation Facility, Sheda, Km 72 Abjua – Lokoja Expressway, P.M.B. 186 Garki, Abuja FCT, Nigeria) and G.A. Bakare (Dept. of Electrical/Electronic Engineering, Abubakar Tafawa Balewa University, Bauchi, Nigeria). E-mail: [email protected] Design, Development and Construction of combined control and protective system for 1.5kw 3-phase induction motor by H.E. Orovwode, Electrical and Information Engineering, Covenant University, Ota, Ogun State e-mail: [email protected] Design and implementation of a gsm activated automobile demobilizer with identification capability by M.S. Okundamiya, J.O Emagbetere and F.O. Edeko, Dept. of Electrical/Electronic Engineering, University of Benin, Benin City, Nigeria. e-mail: [email protected] Remote monitor and controller system for automatic power generation by A.U. Adoghe and O.E. Oluseyi e-mail: [email protected] Design and parameter estimation of a three phase induction motor using a userinteractive computer programme by E.U. Ubeku and E.A. Ogujor, Dept. of Electrical/Electronic Engineering, University of Benin, Benin City, Nigeria. e-mail: [email protected]. The design and fabrication of 6KVA, 150-220 VAC/35-50 VDC electric arc welding machine by S.O. Igbinovia, M.C. Onuoha and O.K. Laogun, Dept. of Electrical/Electronic Engineering, University of Benin, Benin City, Nigeria. e-mail: Design of a brake light failure detecting system by I.T. Thuku (tel.: +2348055085497), A.S. Kadalla (e-mail: [email protected]. Tel: +2348034378394), O.N.Zara (Tel: +2348036059815 e-mail: [email protected]) and O.Laouali, Dept. of Electrical/Electronic Engineering, Federal University of Technology, Yola, Nigeria. A fuzzy logic based process control scheme (design and simulation) by S.N. Ndubisi (Dept. of Electrical/Electronic Engineering, Enugu State, University of Science and Technology, P.M.B. 01660 Enugu, Nigeria. e-mail: [email protected]) and P.A. Airenokhai (NITEL Ltd., International Gateway, Enugu, Nigeria. e-mail: [email protected]).

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 6A:FOOD AND AGRICULTURAL TECHNOLOGY II: 16th April 2008 (2.25 am –4.25 pm)

Session Chair: Prof F F Orunmwense, Edo State Polytechnic, Usen Co-Chair: Dr D E Esezobor, University of Lagos Rapporteurs: J O Okovido/E A Oyadoh (Mrs.) ICERD08087

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Development and performance evaluation of rainwater harvester for drip irrigation of young citrus orchard by S.O. Afolayan (National Horticultural Research Institute, Ibadan, Nigeria), K. Ogedengbe (1Dept. of Agricultural Engineering, University of Ibadan, Ibadan, Nigeria) and S.A. Hassan2. E-mail: [email protected] Farm Stead Planning and layout using prevailing wind direction and pressure as deciding factors by E.A. Opesade and I.S. Obiakor, Farm Structures, Rural Infrastructure and Environmental, Dept. of Agricultural Engineering, University of Agriculture, Abeokuta, Ogun State, Nigeria e-mail: [email protected] Optinum soil conditioning for CELOSIA ARGENTEA propagation subjected to irrigation scheduling by T.A. Ewemoje and J.O. Majekodunmi, Dept. of Agricultural and Environmental Engineering, University of Ibadan, Ibadan, Nigeria. e-mails: [email protected] [email protected] Some engineering properties of cashew nut: its processing by A.F. Alonge, Dept. of Agricultural Engineering, University of Ilorin, Ilorin, Nigeria. e-mail: [email protected] Variations in certain climatic parameters and implications for agricultural production in Makurdi, Benue State of Nigeria by M.O. Isikwue, S.B. Onoja and B.C. Isikwue, Dept of Agricultural and Environmental Engineering, University of Agriculture, Makurdi, Nigeria. E-mail: [email protected] The level of agricultural mechanization in Benue State, Nigeria by V.I. Umogbai and J.A. Terhemen, Dept. of Agricultural and Environmental Engineering, University of Agriculture, Makurdi, Nigeria. e-mail: [email protected]. Tel: +2348033904011. Methods for estimating run off and soil loss in plots under difference plant densities of amarantus by C.S. Okoli, Dept. of Civil Engineering, Federal University of Technology, Akure, Nigeria. E-mail: [email protected] Effect of bioremediation on polycylic aromatic hydrocarbon residues in soil by A.O. Odeh, C.N. Owabor and O.J. Enobakhare, Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. e-mail: [email protected] Effect of lubrication additive on the physical and chemical properties of soyabean oil by E.O. Aluyor and T.O.K. Audu, Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected] Field comparison of irrigation scheduling of tomatoes by C.S. Okoli e-mail: [email protected]. Effects of Preservative Agents on Cassava starch Adhesives by C. E. Akhabue, Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. Development of process and equipment for recovering clean shea kernels from raw shear fruits by A.M. Olaniyan, K. Oje and A. F. Alonge, Facult of Engineering, University of Ilorin, Nigeria. E-mail:[email protected]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 6B: MACHINES AND EQUIPMENT II: 16th April 2008 (2.25 am –4.25 pm) Session Chair: Dr B E Okah-Avae, University of Benin Co-Chair: J O Ehiorobo, University of Benin Rapporteurs: C O Okieimen (Mrs.)/Dr S O Igbinovia ICERD08158

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Design of a universal quick-stop mechanism (UQSM) by O.O. Awopetu and A.A. Aderoba, Dept. of Mechanical Engineering, Federal University of Technology, Akure, Nigeria. e-mail: [email protected] Modeling the effect of extruder screw speed on the mechanical properties of high density polyethylene blown film by L. Uyigue and J.R. Umoh, Dept. of Chemical Engineering, University of Port Harcourt, Port Harcout, Nigeria. E-mail: [email protected]. Design for manufacture of a miniature batch reactor by A.C. Igboanugo (Dept. of Production Engineering) and T.O.K. Audu (Chemical Engineering Dept.), University of Benin, Benin City, Nigeria. E-mail: Design of expeller for processing oils and alkyd resin by A.C. Igboanugo and G.C. Ovuworie, Dept. of Production Engineering, University of Benin, Benin City, Nigeria. email: Evaluation of a laboratory – made Orsat apparatus in the analysis of combustion products of home appliances by Tamuno Tinyemiemaa (Dept. of Mechanical Engineering, Rivers State Polytechnic, Bori, Rivers State, Nigeria. e-mail: [email protected]) and J.U. Okoli (Dept. of Mechanical Engineering, University of Port Harcourt, Port Harcourt, Nigeria. e-mail: [email protected].) The effect of baffles in shell and tube heat exchangers by E.J. Akpabio (1 Dept. of Chemical Engineering, University of Uyo, Uyo, Nigeria), O.I. Oboh1 and E.O. Aluyor (Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected]). A fussy variable structure controller design for spacecraft attitude stabilization by A.S. Kadalla (1 Dept. of Electrical/Electronic Engineering, Federal University of Technology,Yola, Nigeria. E-mail: [email protected] Tel: +234803434378394 Abubakar Tafawa Balewa University, Bauchi, Nigeria. E-mail: [email protected] tel:+2348036460140) and I.A. Usman1 (tel: +2348025526259) Design and fabrication of a methanol steam reformer by E.A. Oyedoh and C.E. Akhabure, Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected] Design and construction of a manual trolley crane by O.R. Edokpia, Dept. of Production Engineering, University of Benin, Benin City, Nigeria. e-mail: The design and fabrication of a cuber machine by F.A. Oyawale, O.E. Oyetunji and L. Saliu, 1Industrial & Produiction Engineering Dept., University of Ibadan, Nigeria, 2Odu’a Investment Company Limited, Ibadan, 3Nigeria Telecommunications, Bodija, Ibadan, Nigeria. E-mail: [email protected]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 6C:INFORMATION AND COMMUNICATION TECH: 16th April 2008 (2.25 am –4.25 pm)

Session Chair: Prof A N Aniekwu, Director, Uniben Network Unit, University of Benin Co-Chair: Dr F A Oyawale, University of Ibadan Rapporteurs: M H Oladeinde/S Apeh, University of Benin ICERD08063

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An electronic patient record management system using smart cards by Monday Eyinagbo, Solomon Ejiro, Adeyemi Tobi, Ebhohimen Daniel, Adeniyi David and Adams David, Dept. of Electrical and Information Engineering, Covenant University, Ota, Ogun State, Nigeria. [email protected] The rain attenuation characteristic at 15GHZ on satellite earth link for selected cities in Nigeria by T.I. Raji, F.A. Semire and O.A. Awodeji, Dept. of Electrical/Electronic Engineering, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria. email: [email protected], [email protected], [email protected] Geoinformation for oil spill disaster management in the Niger Delta region of Nigeria by J.O. Ehiorobo1 and H.A.P. Audu2, Geoinformatics Engineering Unit, Dept. of Civil Engineering, University of Benin, Benin City, Nigeria. e-mail: [email protected], email: [email protected]. Analysis of a helix-fed inverted –F antenna over an infinite ground plane by S.A. Adekola, I.K. Mowete, A.H. Muhammed and C.S. Obiagwu, Dept. of Electrical/Electronic Engineering, University of Lagos, Lagos, Nigeria e-mail: [email protected]. On the analysis and design of uniform linear planer phased away antennas of finite length dipoles by S A Adekola, A I Mowete, A H Muhammad and CC Njoku, Deppt. Of Electrical and Electronics Engineering, University of Lagos, Nigeria. E-mail [email protected] Field equations of the elliptical helical antenna by S.A. Adekola, A.I. Mowete, A.H. Muhammed and C.N. Onwucheka, Dept. of Electrical and Electrical Engineering, University of Lagos, Lagos, Nigeria. E-mail [email protected]. Comparative analysis of the measurement of electric field in Zaria by Akinsanmi Olaitan, B.G. Bajoga, K.S. Farayola, B.A. Adegboye, M.B. Muca1 zu and D,.D. Dajab, Dept. of Electrical Engineering, Ahmadu Bello University, Zaria, Nigeria. e-mail: [email protected]. Comparative analysis of the measurement of electric field in non-harmattan period in Zaria by Akinsanmi Olaitan and B.C. Bajoga, Dept. of Electrical Engineering, Ahmadu Bello University, Zaria, Nigeria. E-mail: [email protected]. Implementation of a multi-channel full duplex wireless intercom system for system audit and management control by S.T. Wara, A. Abayomi-Alli and I.R. Asemota 1 Product Development Energy Centre, Electrical and Computer Engineering Dept., Igbinedion University, Okada, Edo State, Nigeria. a [email protected], [email protected] Community (campus) based radio communication system by S.T. Wara, C.D. Odikayor, A. Abayomi-Alli and O.A. Osunbor 1Product Development Energy Centre, Electrical and Computer Engineering Dept., Igbinedion University, Okada, Edo State, Nigeria. a [email protected], [email protected] An investigation of microwave link degradation due to atmospheric conditions (a case study of Akure – Owo digital microwave linkg) by P.O. Otasowie and F.O. Edeko, Dept. of Electrical/Electronic, University of Benin, Nigeria (e-mail: [email protected]) Investigation of the characteristic of indoor radio propagation by J.O. Emagbetere and F.O. Edeko, Dept. of Electrical/Electronic Engineering, University of Benin, Nigeria

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 7A: SYSTEMS DESIGN AND ANALYSIS I: 16thApril 2008(4.40pm–6.40 pm) Session Chair: Prof B U Anyata, University of Benin Co-Chair: Engr. Adiuku-Brown, NPTAP, Abuja Rapporteurs: P Otasowie/Emeka Amalu, University of Benin ICERD08017

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Dynamic modeling of multibody constained mechanisms Part I: rigid links robot by A. Haladou (Departement de Physique, Faculte des sciences, Universite Abdou Moumouni, Niamey, Niger, BP 10662. [email protected]), A. Maalej ( Laboratoirede Systemes Electromecaniques (LASEM), Ecole Nationale d’Ingenieurs de Sfax (ENIS) Route de Soukra-BP, W – SFAX, Tunisie) and F. Gorbel (Dept. of Mechanical Engineering, Rice University, 6100 South Main street, Houston, Texas 77251 1892, USA Dynamic modeling of multi-body constrained mechanisms Part II: Flexible links robot by A. Haladou (Departement de Physique, Faculte des sciences, Universite Abdou Moumouni, Niamey, Niger, BP 10662. [email protected]), A. Maalej ( Laboratoirede Systemes Electromecaniques (LASEM), Ecole Nationale d’Ingenieurs de Sfax (ENIS) Route de Soukra-BP, W – SFAX, Tunisie) and F. Gorbel (Dept. of Mechanical Engineering, Rice University, 6100 South Main street, Houston, Texas 77251 1892, USA Project – Based Education Using Distributed-Teams: Experiences Of Tokyo – Based And Stanford-based teams by C. Mbohwa [email protected] Fractal analysis of area-perimeter relationship of some selected countries of the world by A.E. Adeleke and T.A.O. Salau, [email protected] Solving time management problem in transportation – an optimization algorithm by A.A. Adeala and A.T. Layeni, Dept. of Mechanical Engineering, Olabisi Onabanjo University, Ago-Iwoye, Ibogun Campus, Ogun State, Nigeria. E- mail Municpal waste transport network analysis by A.T. Layeni, M.A. Sulaimon, A.O. Adesina and A.A. Adeala, Dept. of Mechanical Engineering, Olabisi Onabanjo University, Ago-Iwoye, Ibogun Campus, Ogun State, Nigeria. E-mail: [email protected] A bi-objective optimal waste collection scheduling with waste volume and biodegradability considerations by Ladi Ogunwolu, O.A. Alli and O.P. Popoola, Dept. of Systems Engineering, University of Lagos, Lagos, Nigeria. E-mail: [email protected] Maintenance Productivity measurement: Case study of a manufacturing company by O.A. Alli, Ladi Ogunwolu and Olukayode Oke, Dept. of Systems Engineering, University of Lagos, Lagos, Nigeria. E- mail: [email protected] Optimal labour allocation in a challenging environment: dynamic programming model by S.D. Okonta and O.K. Anthony, Dept. of Statistics Delta State Polytechnic, Otefe – Oghara, Delta State, Nigeria. E-mail: [email protected] The CRAI Model: A framework for managing project knowledge by P.I. Oluikpe, Research Associate, Dept. of Civil and Building Engineering, Loughborough University, Leicestershire LE 113TU, U.K. E-mail. [email protected] Dynamic modeling of triple glazing, single pass, single flow natural convection solar energy collections for agricultural dryers by D V C Onuoha, Federal Ministry of Environment, Abuja, Nigeria

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 7B: CONSTRUCTION MATERIALS: CONCRETE: 16th April 2008 (4.40 pm –6.40 pm)

Session Chair: Dr J U Okoli, University of Port-Harcourt Co-Chair: Dr. Folarin Alonge, University of Ilorin Rapporteurs: J A Akpekpe/Joy Emagbetere (Mrs.) ICERD08050

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Empiricism in Reinforced Concrete design: Part 1 Predicting concrete properties by D.N. Nwokoye and C.A. Ezeagu Dept. of Civil Engineering, University of Benin, Benin City, Nigeria E-mail: [email protected]. Tel: +2348038766208, +2348023454175 Empiricism in reinforced concrete design Part II: Cube and bending strength relationships by D.N. Nwokoye and C.A. Ezeagu, Dept. of Civil Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected] Tel: +2348038766208, +23480233454175 Taking lateritic soils for granted in highway design and construction in Southern Nigeria by Olumide Omotosho, University of Port Harcourt, Port Harcourt, Nigeria. Email. Durability-based appropriateness of sawdust concrete for rigid pavement by O.M. Ogundipe (Dept. of Civil Engineering, University of Ado-Ekiti, Ekiti State, Nigeria) and Y.A. Jimoh (Dept. of Civil Engineering, University of Ilorin, Ilorin, Kwara State, Nigeria) e-mail: [email protected]. Improving the properties of concrete using chemical admixtures in the warm humid climate by P.A. Okereke, Dept. of Building, Imo State University, P.M.B. 2000, Owerri, Nigeria. e-mail: [email protected] The quality of concrete made with typical Benin City silty sand by O.E. Alutu and E.N. Ejike, Dept. of Civil Engineering, e-mail: [email protected] The influence of vibration time and sand type on the compressive strength of sandcrete hollow blocks by O.E. Alutu and A. Omoregie, Dept of Civil Engineering, University of Benin, Benin City, Nigeria. e-mail: [email protected] Determination of thermophysical properties of sawdust with additives of cement and silica clay by I.O. Ogunleye, Dept. of Mechanical Engineering, University of Ado-Ekiti, Ado-Ekiti, Nigeria. email: [email protected]. Emerging construction technologies enables environmental protection: Rubberized concrete by G. Senthil Kumaran1 nurdin Mushile1 M.I. Laxmipathy2, 1Dept. of Civil Engineering & Environmental Technology KIST, BP 1900, Kigali, Rwanda 2School of Civil Engineering, SRM University, Tamilnadu, India e-mail: [email protected]. The potential use of periwinkle shell as coarse aggregate for concrete by J.O.Osarenmwinda and A.O. Awaro, Dept. of Production Engineering, University of Benin, Nigeria. E-mail: [email protected].

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 7C: OIL AND GAS TECHNOLOGY I 16th April 2008 (4.40 pm –6.40 pm) Session Chair: Prof A Oni, University of Benin Co-Chair: Dr. S O Onahaebi, University of Benin Rapporteurs: Dr F A Aisien/O Omodamwen, University Benin ICERD08041

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Maximizing generated energy usage through combined cycle cogeneration by C.G. Enyi. [email protected]) and D. Appah, Dept. of Petroleum and Gas Engineering, University of Port Harcourt, Nigeria Water coning calculation and prediction by A.A. Adeniji, Dept. of Petroleum Engineering, University of Benin, Benin City, Nigeria. e-mail: [email protected] Analysis of declining incomes by A.A. Adeniji and K.I. Idigbe, Dept. of Petroleum Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected] Improving seismic technology in the sedimentary basins of Nigeria by Kess Asikhia (Dept. of Mechanical Engineering. E-mail: [email protected]. Tel: +2348020351438) and Ebinedia Itohan (Dept. of Petroleum Engineering. E-mail: [email protected], Tel:+2348068669048) Determination of needed workforce in the oil sector: Leontief Approach by S.D. Okonta (Dept. of Statistics, Delta State University, Otefe – Oghara, Delta State, Nigeria. E-mail: [email protected]) and C.R. Chikwendu (Dept. of Mathematics, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria. E-mail [email protected] Pressure interference behaviour of both horizontal and vertical well combination in an infinite – acting reservoir system by P.U. Giegbefumwen and E.S. Adewole, Petroleum Engineering, Dept., University of Benin, Nigeria. E-mail: [email protected] Determination of flow regimes of a horizontal well in an infinite-acting reservoir system by K.E. Ovwigho and E.S. Adewole Petroleum Engineering, Dept., University of Benin, Nigeria. E-mail: [email protected] Assessment of refining schemes for crude oil processing using Microsoft Excel by H.N. Johnson and S.E. Ogbeide, Dept of Chemical Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected]. Risk evaluation of pipeline failures: A Nigeria perspective by G.O. Ariavie, O.P. Aigbe, O.K. Ezeaku, S.A. Omojowo and K.H. Usiagwu, Dept. of Mechanical Engineering, Univiersity of Benin, Benin City, Nigeria. e-mail: [email protected], [email protected]. Optimisation of managed pressure drilling with casing by M.B. Oyeneyin and V.C. Kelessidis2, 1Virtual Well Engineer Ltd/Robert Gordon University, Aberdeen, UK, 2 University of Crete, Greece e-mail: [email protected]. A new correlation for the viscosity of natural gas by P.U. Ohirhian, Dept. of Petroleum Engineering, University of Benin, Nigeria and I.N. Abu, Shell Petroleum Dev. Co. Warri. e-mail: [email protected]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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Technical Session 8A: MACHINES AND EQUIPMENT III: 17th April 2008 (8.00 am –10.00 am) Session Chair: Prof Richard Weston, Loughborough University, Leicestershire, UK. Co-Chair: Dr S K Kadala, Fed. Univ. of Technology, Yola Rapporteurs: Dr. A I Igbafe/Dr. S O Osuji, Universsity of Benin ICERD08023

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Design and development of palm waste briquette stove for domestic and industrial usage by C.O. Ilechie, G.F. Aibangbee and S.R. Ogbelechi, Nigerian Institute for Oil Palm Research (NIFOR), Benin City, Nigeria. [email protected] Development of an adjustable temperature sensing system for a dual preservative unit by B. Kareem, Dept. of Mechanical Engineering, Federal University of Technology, Akure, Ondo State, Nigeria. [email protected], [email protected] Design and construction of human body resistance and a temperature measuring device by I.R. Ilaboya, Dept. of Chemical Engineering, Igbinedion University, Okada, Edo State, Nigeria. e-mail: [email protected] tel: +2348038027260 Process conditions affecting the yield and quality attributes of oil mechanically expressed from castor by A.M. Olaniyan, Dept. of Agricultural Engineering, University of Ilorin, Nigeria. e-mail: [email protected] Development and performance evaluation of a manually operated cowpea thresher by V.I. Umogbai and A. Shehu, Dept. of Agricultural and Environmental Engineering, University of Agriculture, Makurdi, Nigeria. e-mail: [email protected]. Similitude of soil-machine systems by D.D. Yusuf Dept. of Agricultural Engineering, Faculty of Engineering, Ahmadu Bellow University, Zaria, Nigeria. e-mail: [email protected]. Human body resistance and temperature measurement device by S.T. Wara, I. Oghogho, A. Abayomi-Alli and M.S. Essien (contacts as in ICERD08229 (1a and 1b) Indigenising the operations of the Nigerian postal Service (NIPOST) by O..F. Edeh and F.C. Obi, Dept. of Mechatronics Electronics Development Institutes, (ELDI), Akwa, (NASENI) Nigeria e-mail: [email protected]. Application of Enterprise Modelling (EM) principles to improving the performance of a semi-automated production system, J.O. Ajaefobi & R .H. Weston MSI Research Institute, Loughborough University, LE11 3TU, UK Forces acting on a screw element during clamping, bolting, presswork and load lifting and lowering operations I – Force Analysis by D V C Onuoha, Fed. Ministry of Environment and Urban Development, Abuja, Nigeria Force acting on a screw element during clamping, bolting, presswork, and load lifting and lowering operations II – Thread Stresses by DVC Onuoha, Federal Ministry of Environment and Urban Develop,ent, Abuja, Nigeria An experimental autonomous path tracking mobile robot by Sanancryake Hasitha and Akinsanmi Olaitan, Dept of Electrical Engineering, Ahmadu Bello University, Zaria

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Technical Session 8B: SYSTEMS DESIGN AND ANALYSIS II 17th April 2008 (8.00 am –10.00 am) Session Chair: Prof G C Ovuworie, University of Benin Co-Chair:Dr J Ejon, University of Johannesburg, South Africa Rapporteurs: Dr. N P Orobor/D I Igbinomwanhia, Universsity of Benin ICERD08099

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Solver – a modern Operations Research Tool by T.C. Oghenekparobor, Dept. of Statistics, Delta State Polytechnic, Otefe-Oghara, Delta State, Nigeria. e-mail: [email protected]. Performance Evaluation of Quadrature Phase Shift Keying (QPSK) and Binary Phase Shift Keying (BPSK) in fast and frequency non-selective Rayleigh fading channel by Z.K. Adeyemo, Dept. of Electrical/Electronic Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria. E-mail: [email protected]. Stiffly stable second derivative continuous hybrid linear multistep methods for stiff IVPs in ODEs by R.I. Okuounghae1 and M.N.O. Ikhile2 , Dept. of Mathematics, University of Benin, Benin City, Nigeria. e-mail: [email protected], e-mail: [email protected] System potential-based productivity evaluation model by C.O. 1Anyaeche, and 2A.E. Oluleye, Dept, of Industrial and Production Engineering, University of Ibadan, Ibadan, Nigeria. e-mail: [email protected], email:ayodeji:[email protected]. Evaluating solution methods to bicriteria scheduling problems by E.O. Oyetunji (Dept. of Applied Mathematics and Computer Science, University of Development studies, Ghana. E-mail: [email protected]) and A.E. Oluleye (Dept. of Industrial and Production Engineering, University of Ibadan, Ibadan, Nigeria. e-mail [email protected]). Evaluation and improvement of Dvorak keyboard layout using CADWORK by U.J. Udosen, Dept. of Production Engineering, University of Benin, Benin City, Nigeria. email: [email protected] Optimization of the performance of super-cruise engine with isothermal combustion inside the turbine using energy method by A.S. Adavbiele and S.O. Amiebenoman, Dept. of Mechanical Engineering, Ambrose Alli University, Ekpoma, Edo State, Nigeria. email: [email protected] Computer-aided drafting of motorcycle assembly by S.B. Adejuyigbe and O.S. Adebowale, Mechanical Engineering Dept., Federal University of Technology, Akure, Nigeria. e-mail A computer – aided raw materials requirement planning (CARMRP) for job shop: A case study by S.B. Adejuyigbe and J.A. Ayeni, Dept. of Mechanical Engineering, Federal University of Technology, Akure, Nigeria. e-mail: A study of Urban traffic management: The case study of Lagos State Traffic Management Authority by E.I. Bello and C.I. Usifo, Dept. of Mechanical Engineering, Federal University of Technology, Akure, Nigeria. E-mail: [email protected]

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Technical Session 8C: OIL AND GAS TECHNOLOGY II: 17th April 2008 (8.00 am –10.00 am) Session Chair: Prof Emmanuel Eneyo, South Illinois Universit, USA Co-Chair: Dr U J Udosen, University of Benin Rapporteurs: O R Edokpia/Emeka Amalu ICERD08046

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Comparing performances of horizontal and vertical wells by K.I. Idigbe and A.A. Adeniji, Dept. of Petroleum Engineering, University of Benin, Benin City, Nigeria. Email: [email protected] Pressure drawdown for a well producing at a variable rate by A.A. Adeniji, Dept. of Petroleum Engineering, University of Benin, Benin City, Nigeria. E-mail: [email protected] Pressure derivative characteristics of a crossflow layered reservoir with vertical wells by D. Akhikpemelo and E.S. Adewole Petroleum Engineering, Dept., University of Benin, Nigeria. E-mail: [email protected] Interference test analysis of a crossfolw reservoir with vertical well by S. Babatunde and E.S. Adewole Petroleum Engineering, Dept., University of Benin, Nigeria. E-mail: [email protected] Optimisation of refinery operations using Microsoft Excel by G I Okoh and S E Ogbeide, Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria. Email: [email protected] Swelling characteristics of shales and their dispersion in drilling muds by W.O. Emofurieta (Dept. of Geology, University of Benin, Benin City, Nigeria) and A.O. Odeh (Dept. of Chemical Engineering, University of Benin. E-mail: [email protected] Prevention and control of hydrates formation in natural gas pipelines by E.M. Benedict, A.O.Odeh (e-mail: [email protected]) and S.E. Ogbeide (e-mail: [email protected]), Dept. of Chemical Engineering, University of Benin, Benin City, Nigeria Influence of gamma radiation on the radiofrequency dielectric properties of Nigerian crude oil by O.D. Osahon and O.D. Nworgu, Dept. of Physics, University of Benin, Benin City, Nigeria. e-mail: [email protected]. Tel: +2348056070262 Sand production forecast for unconsolidated gas reservoirs by M.B. Oyeneyin (Robert Gordon University, Aberdeen, U.K.) and Babatunde Moriwawon (Shell Petroleum Development) e-mail: [email protected] Equations for the Z-factor and compressibility of Nigerian natural gas by P.U. Ohirhian, Dept. of Petroleum Engineering, University of Benin, Nigeria. e-mail: [email protected]

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Technical Session 9A: THE ENVIRONMENT: 17th April 2008 (10.25 am –12.25 pm) Session Chair: Dr K I Idigbe, University of Benin Co-Chair: Dr Kareem, Fed. University of Technology, Akure Rapporteurs: Dr A Igbafe/Dr. J A Akpobi ICERD08010

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Urban communities impacts upon storm water open channels in a developing country, the example of Abidjan (Core de Ivoire): Litter build-up and waste waterself purification by Jean-Marie P Quattara, Lacina Coulibaly and Germain Gourene [email protected] Reduction of fire incidents arising from electrical faults in buildings by S.O. Onohaebi and S.T. Apeh, Electrical/Electronic Engineering Dept, University of Benin, Benin City, Nigeria. e-mail: [email protected]. Modeling of sediment transport capacities of Ogbese and Owena Rivers in South Western Nigeria by C.S. Okoli, Dept. of Civil Engineering, Federal University of Technology, Akure, Nigeria. E-mail: Treatment of Brewery Wastewater Using Enzymes by Aisien, F.A., Oyakhilome, G.E. and Aisien, E.T. Dept. of Chemical Engineering, University of Benin, Benin City. Assessment of hydraulic performances of drainage channels in UNAAB Campus by G.A. Bolaji, Dept. of civil Engineering, University of Agriculture, Abeokuta, Nigeria. Email: Gaseous emission attributed pollution in the oil producing communities in Nigeria by F.A. Gabriel (VEAN Associates Nigeria Ltd, Nigeria e-mail: [email protected]) and A.J. Akpan (Akwa Ibom /state University of Technology, (AKUTECH), Nigeria Recycled tire materials as components of novel structures by Joshua L Neale (Henry Molded Products Inc., Lebanon, USA) and Madara M Ogot (University of Nairobi Enterprises and Services Ltd, Nairobi, Kenya. [email protected], [email protected]) Appropriate design of rural roads by O.I. Odumodu, Dept. of Civil Engineering, Federal Polytechnic, Oko, Anambra State, Nigeria Improved sawdust briquette: an alternative source of fuel by J.O. Osarenmwinda ([email protected]) and S.Imoebe, Dept. of Production Engineering, University of Benin, Nigeria Air Pollution in Broll Island by E E Ukpebor (Dept. of Chemistry), A I Igbafe, K O Obahiangbon and E O Aluyor, Dept. of Chemical Engineering, University of Benin, Benin City, Nigerian.

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Technical Session 9B: CONSTRUCTION AND STRUCTURES: 17th April 2008 (10.25 am –12.25 pm)

Session Chair: Prof B U Anyata, University of Benin Co-Chair: Dr. E O Oyetunji, University of Development Studies, Ghana Rapporteurs: Dr E U Ubeku/B A Aburime, University of Benin ICERD08025 ICERD08056

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Maintenance of roads in Nigeria: A necessity for sustainable development by J.O. Aribisala and O.M. Ogundipe, [email protected] Effect of compactive effort on lime treated black cotton soil using bagasse ash as admixture by K.J. Osinubi, T.S. Ijimdiya (e-mail: [email protected]), Dept. of Civil Engineering, Ahmadu Bello University, Zaria, Nigeria and I. Nmadu, Federal Ministry of Transportation (Works), Field Department, Kaduna, Nigeria Lime stabilization of black cotton soil using bagasse ash as admixture by K.J. Osinubi, T.S. Ijimdiya, Dept. of Civil Engineering, Ahmadu Bello University, Zaria, Nigeria. (e-mail: [email protected]) and I. Nmadu, Field Department, Federal Ministry of Transportation (Works), Kaduna. Investigation of the compatibility of Ceiba Pentandra and Bombax Bounopozense flake with ordinary Portland Cement by S.O.O. Badejo, R.A. Baiyewu, I.T. Ademola, M.I. Adeniyi and O.S. Areo, Dept. of Forest Products Development & Utilization, Forestry Research Institute of Nigeria, Jericho, P.M.B .5054, Ibadan, Nigeria, E-mail: [email protected] Potentials of Eupatorium Odoratum for the production of cement – bonded composite by S.O.O. Badejo (1Dept. of Forest Products Development & Utilization), R.A. Baiyewu1, O.N. Amoo-Onidundu1, B. Ajayi (2Dept. of Forestry and Wood Technology), S.O. Taleat1 and O.A. Ayoola1 Forestry Research Institute of Nigeria, Jericho, P.M.B. 5054, Ibadan, Nigeria. E-mail: [email protected] Innovations in mass housing delivery systems in Nigeria by P.A. Okereke, and C.C. Ezeh, Dept. of Building, Imo State University, Owerri, Nigeria. e-mail: [email protected]. Dimensional stability and bending properties of cement-bonded flake board produced from APA and BOMBAX by S.O.O. Badejo, R.A. Baiyewu, I.T. Ademola, K.S. Aina and A. Ilori, Dept. of Forest Products Development and Utilization, Forestry Research Institute of Nigeria, Jericho, P.M.B. 5054, Ibadan, Nigeria. e-mail: [email protected]. Accuracy of static differential GPS techniques: Implications for structural deformation monitoring by J.O. Ehiorobo, Dept. of Civil Engineering, University of Benin, Benin City, Nigeria. e-mail: [email protected] Innovation in architectural engineering: the correlation of visual art and mathematics as instrument by B.A. Ozokehara (Dept. of Fine & Applied Arts, Delta State Polytechnic, Ogwashi-Uku, Delta State, Nigeria) and C.F.R. Ozokehara (Dept. of Statistics, Delta State Polytechnic, Otefe-Oghara, Delta State, Nigeria). E-mail: [email protected] Exploiting the potentials of rice husk ash for construction in Nigeria by A.A. Akindahunsi and O.O. Alade, Dept. of Civil Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria. E-mail: [email protected], [email protected]. Torsional resistance of steel reinforcement used in the construction industry of Nigeria by O.U. Orie, Dept. of Civil Engineering, University of Benin, Nigeria. [email protected]

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Technical Session 9C: SYSTEMS DESIGN AND ANALYSIS III: 17th April 2008 (10.25 am –12.25 pm) Session Chair: Prof B. O. Onyekpe, University of Benin Co-Chair: Dr. Senthil Kumaran, Kigali Insstituteof Science & Tech., Rwanda Rapporteurs: P E Amiolemhen/Emeka Amalu, University of Benin

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Mathematical modeling of an improved design for a rail carriage suspension system for the wagons used in Zimbabwe by Charles Mbohwa ([email protected]) and Chester Murasiki ([email protected]) Load limit for lifting-related low back pain preventjon: A mathematical mode by S.O. Ismaila (Dept. of Mechanical Engineering, University of Agriculture, Abeokuta, Nigeria), O.E.Charles-Owaba (Dept. of Industrial & Production Engineering, University of Ibadan, Ibadan, Nigeria). E-mail: [email protected]. Innovation technology: systems dynamics approach for setting a manufacturing safety programme by K.A. Adebiyi (Dept. of Mechanical Engineering, Ladoke /akintola University of Technology, Ogbomoso, Oyo State, Nigeria), O.E. Charles – Owaba (Dept. of Industrial and Manufacturing Production Engineering, University of Ibadan, Nigeria, Southern Illinois University, Edwards ville, IL 62026-1805, USA). E_mail: [email protected] Solving the machine set-up problem: a case with the University Engineering Workshop by V.O. Oladokun (Dept, of Industrial & Production Engineering, University of Ibadan, Ibadan, Nigeria), E.S. Eneyo (Dept. of Industrial & Manufacturing Engineering, School of Engineering, Southern Illinois University, Edwards ville, Il 62026-1805, USA) AND o.e. Chrles-Owaba1 (e-mail: [email protected]). Investigation of the vibration mode of a long bone- the ulna by O.D. Nworgu and D.O Osahon, Dept. of Physics, University of Benin, Benin City, Nigeria. E-mail:[email protected] The role of augmented reality in forest management by G. Senthil Kumaran and K.R. Santhi, Kigali Institute of Science and Technology, B.P. 3900, Kigali, Rwanda email: [email protected]. Determination of ground vibrations and noise levels during blasting operations by J.M. Akande and E.O. Ifelola Dept. of Mining Engineering, Federal University of Technology, Akure, Nigeria. E-mail: seyfelzk4@yaho Journey to work characteristics of Ado-Ekiti by Aluko Oluwasegun Oluyemi, Dept, of Civil Engineering, University of Ado-Ekiti, Nigeria. E-mail: [email protected] Learning effect and precedence constraints in single machine processing by Tsetimi Jonathan, Dept. of Business Administration, Delta State University, Abraka, Delta State, Nigeria. E-mail: [email protected]. Radial flow of slightly compressible fluids: A finite-element finite-difference approach by J.A. Akpobi (Dept. of Production Engineering) and E.O. Akpobi (Dept. of Petroleum Engineering), University of benin, Benin City, Nigeria

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

CONFERENCE PROCEEDINGS

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

GUEST LECTURE

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Responsive Production Systems and Roles that Robots can Play R .H. Weston MSI Research Institute, Loughborough University, LE11 3TU, UK

Abstract With increased product dynamics world-wide, the average economic lifetime of production systems is falling. Industrial robots are widely assumed to be inherently flexible and therefore that they can function as a programmable building block of response production systems. This paper reviews common capabilities of contemporary industrial robotic systems and investigates their capability to extend the useful lifetime of production system by coping with different types of product dynamic. Also considered are relative capabilities of conventional programmable robots and an emerging generation of programmable and configurable component-based machines.

1. Introduction The business environment world-wide has become more dynamic and uncertain and to compete successfully, short or long term, a new breed of responsive manufacturing company is required. To be competitive such companies need to have one or more fast and efficient complex systems of people, typically supported by IT and automation. Commonly those complex systems are required to: (1) obtain orders (by achieving product selling and marketing, contract negotiation, costing and estimating and so forth) and (2) fulfil orders (by realising product design and engineering, materials processing, component manufacture and product assembly, production planning and control and supply chain control and management). This paper considers ways of achieving responsive order fulfilment with emphasis on (a) the design of responsive production systems and (b) using state of the art modelling concepts and virtual engineering tools to illustrate potential roles that robots and related automated systems can play when creating responsive production systems.

+

desire for customised products

advances in materials & production technology

+

+ +

increased product variety

more frequent product engineering

global competition

reduction in production volumes

+ +

+

increased product mix

reduced product life-times

+

unit cost reduction

other factors

+

increased need for agile & flexible production systems

+ + +

+

more frequent production systems engineering

increased need for complexity management

+ need for new modelling & VE technologies

+

need for Lean production

+

Figure 1 Need for a new generation of change capable production systems Figure 1 uses a causal loop model to indicate reasons why production systems (which may be required for materials processing, component manufacture, production assembly and other related production processes) pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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need often to be change capable. A key dimension is the need to cope with a growing product dynamic world-wide. That dynamic typically takes the form of one or more of the following: 1) 2) 3) 4)

Increased product variance during normal operation of production systems More varied production volumes, again during normal operation More varied production mix, during normal operation More frequent significant change requirements, when new products are engineered and introduced into production

Of course some companies (and industries) suffer less than others from impacts of product dynamics. But there is a growing requirement world-wide for production systems with capabilities to cope with 1) through 4). In general the impacts of 1) through 3) should be taken into account when (i) production systems are designed and engineered and (ii) when their day to day running is planned and controlled. But when product dynamics of type 4) lead to very significant requirements change there will also be a need to achieve significant redesign and re-engineering of production systems; in respect of (A) the activity flows (or processes) they need to enact, (B) the human and technical resource systems they require, and (C) the way in which workflows through them are organised and pulled or pushed. In some production environments significant production systems change may be necessary even on a day to day basis. So how can industry satisfy this growing need? An academic answer is that a number of ‘manufacturing concepts’ and ‘OEM solutions’ have been conceived and developed, that industry world-wide can deploy. But in general industry is not well served with means by which they can make well informed choices between the philosophies and OEM choices that are available. Hence in the next section of this paper some key philosophies and OEM choices are reviewed in outline. Subsequently this paper has particular focus on the potential role of robot technology. This is because inherently robots provide one type of flexible OEM solution and therefore should play a future potential role in realising responsive production. This suggestion is investigated and several conclusions drawn as to (a) stereotypical roles robots can that play and (b) how next generation virtual engineering technologies might support ongoing redesign of automated systems, including robots.

2. Literature Overview Many manufacturing philosophies have emerged in recent decades that typically are based around a central idea (or concept) that industry can focus on to realise some form of competitive advantage; be that ultimately through improved product quality, timeliness of product delivery or reduced processing and/or product costs. Here the term product is used very generally and is assumed to include services as well as artefacts and software elements of products; that at one extreme might be a transport system for a developing country, a football stadium to a commercial aeroplane, to commodities like cars and white goods, through computer-based products to electro-mechanical components (like electric drives and sensory elements) and at the simpler extreme can be hardware items such as knives, forks, nuts and bolts. Table 1 lists some well known examples of manufacturing philosophies conceived by academia and industry. There is great overlap of concerns and some philosophies are really derivatives of others. Table 1: Example Manufacturing Philosophy, Methods, Tools, Mechanisms and OEM Solutions Philosophy LEAN, JIT, Pull Agile, RMS, Postponement, Mass Customisaton GT, CM

Methods and Tools 5s Kanban 6 sigma Balance Score Cards ERP

OEM Solutions Semi Generic Particular FMS ABB Robots FAS Kuka Robots CMM Adept Robot Cell Control Siemens distributed CNC controls

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria TQM IMS, Holonic CE Economy of Scope Economy of Scale

CAE PDM Simulation technology LAN technology Database technology Agent technology

Robot PLC Flexible machines Special purpose dedicated machines Three term controllers

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Teamcentre (PLM) Delmia (simulator) JACK (simulator) SAP (ERP)

JIT (Yasuhiro 1998), LEAN (Womack et al 1991) and Pull are interconnected philosophies focused on reducing different kinds of waste, such as over-production, inappropriate inventory, inefficient resource usage, etc. Common ideas that interconnect Agile (Mason-Jones et al 2000), Reconfigurable Manufacturing Systems (RMS)(Koren et al 1999), Postponement and Mass Customisation (Loe 1998) centre upon being flexible and responsive to changing requirements. Postponement and Mass Customisation both embrace responsiveness ideas but also borrow ideas from the LEAN school of thinking. Group Technology (GT) (Suresh and Kay 1998), Cellular Manufacture (CM) (Angra et al 2008) and RMS share notions about similarity (of products, processes and resources) where for example RMS builds upon similarity concepts so as to identify ways of realising responsiveness. Other philosophies such as Total Quality Management (TQM) (Ittner and Larcker 1995) centre on thinking about quality concerns (i.e. ‘fitness for purpose’). Concurrent Engineering (CE) (Smith et al 1996) shares ideas with JIT but is normally centred on product engineering issues and opportunities to reduce lead-times via method and possibly IT tool application. Other philosophy is concerned with intelligence, learning and adaptation; such as Intelligent Manufacturing Systems (IMS) and Holonic Systems (Suda 1989 & 1990). In general it is true that there will be a trade off between timeliness, quality and cost and seldom will a manufacturing enterprise (ME) achieve competitive behaviours on all three fronts. It follows that the design of any given ME must recognise key characteristics of its business environment as well as understand impacts arising from associated engineering and operational constraints. This requirement is illustrated conceptually by Figure 2. If these characters and their impacts are well known, in principle the said ME can select a manufacturing philosophy which suits its specific circumstance; so that significant competitive advantage can be achieved relative to other MEs. But the reality is very complex indeed; especially if a given ME needs (which is very common) to diversify its product range. In such cases typically MEs must use a finite human, IT and machine resource to achieve so called economies of scope, as well as economies of scale (Cui and Weston 2008). The underlying notion of economy of scope is that by making a range of product types, the peaks and troughs of any one can be evened out so that a commonly used resource can be well utilised. Ultimately this can extend the useful lifetime of a production system and indeed an entire ME. Economy of scale is appropriate when product markets require high volume production, so that needed processes, resources, and planning and control systems can be finely tuned. Achieving dual economies of scope and scale requires a suitable combination of Agile and LEAN schools of thought.

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business environment governmental impacts

stakeholders schedule program configure

customers suppliers

product dynamic

production demands

production materials

supplier chain configurations

plan

manage

control

monitor production processes production resources

products: of increased value

legislation

Production System

engineering environment

market structures competitors

market trends & values

Figure 2 Next generation production systems must continue to fit their changing environments From the foregoing the reader should deduce that the process of choosing a suitable guiding manufacturing philosophy is not a trivial one. What is more, if a bad philosophy is chosen, such that production systems developed and deployed badly match their engineering and business environment, the likelihood is that the ME will fail sooner or later. Further, as their environments change over time the best choice of philosophy will change; as might that best choice with respect to different product groups made by a ME. Table 1 also illustrates some example methods and tools that have been devised to enable industry to implement their guiding philosophy after it has been chosen. For example, Kanbans are essentially mechanisms to implement Pull while ERP software tools are designed to PUSH products into production systems. 5’s methods and tools are used to implement LEAN and 6sigma is designed mainly to underpin TQM. However, some implementation tools straddle more than one philosophical basis, such as Balanced Score Cards. But once again industry is faced with a dilemma as to which method, tool and mechanism to choose to deploy. Also illustrated by Table 1 are examples of semi-generic and particular OEM solutions that IT, machine and large scale system vendors offer industry as proven means of achieving different ‘styles’ of production. Flexible Manufacturing Systems (FMS) and Flexible Assembly Systems (FAS) constitute a well established class of OEM solution, the former normally being centred on the use of machining systems, the latter on robotic and related manipulator systems; but specific proprietary examples of these OEM solutions may include both CNCs and robots. Particular instances of OEM solutions might be a flexible machining cell or a specifically designed and engineered car engine assembly line system, centred for example on the use of Kuka robots and/or ABB and Siemens distributed controls. In general any particular FMS or FAS will have been designed to do a fairly specific job or range of jobs, on a constrained family of products; but they will be reprogrammable in the sense that different machine tool and/or robot programs can be loaded into machine controllers and because different tools, fixtures, etc, can be automatically selected. It follows that they can respond to some constrained product dynamic of types 1) through 4) as described in section 1, but whether or not short or long term they can operate competitively on quality and cost grounds will depend upon specific business and engineering environmental conditions now and into the future. General conclusions can be drawn about the state of play in regards to concepts, methods, tools and OEM solutions available to industry today. These include: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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(II)

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greatest emphasis in academia and industry OEM solutions to-date has been on organising and supporting the deployment of technological resources (i.e. IT and machine systems). But commonly it is people (and their way of working) that constitute the prime ME resource and who will be the prime determinant of competitiveness; and seldom to date has industry used quantitative and analytic techniques to select and deploy suitable philosophy, methods, etc, on an ongoing basis.

Ongoing research of the present authors (and their colleagues in the MSI (Manufacturing Systems Integration) Research Institute and the UK Centre of Excellence in Customised Assembly (CECA) at Loughborough University) is centred on addressing current limitations arising from (I) and (II).

3. Need for ‘Change Capability’ In this section some terminology will be defined as a basis for quantifying the extent to which production systems are flexible, and hence responsive to different types of product dynamic. Over the last two decades much has been written about the need for flexible manufacture. Initially the main body of literature focused on the need for flexible stand-alone machines, i.e. robots, CNC machines, machine vision, and so on. Since which time the focus of attention has broadened through defining requirements of flexible groupings of machines, control systems and people (and particularly with respect to the design and operation of FMSs, FASs, flexible production lines and human teams) onto defining requirements of flexible manufacturing companies and partnership enterprises. However there are problems with interpreting some of this literature as often the scope of definitions overlap: some terms are essentially aggregates of others, whilst unfortunately identical terms used by alternative authors might mean something altogether different. In the context of manufacturing, Buzacott (1982) defined flexibility as the ability of a system to process a wide variety of parts or assemblies, without intervention from outside to change the system. He differentiated ‘job flexibility’ (i.e. the ability of the system to cope with different jobs to be processed by a system) from ‘machine flexibility’ (i.e. the ability of the system to cope with changes and disturbances at machines and workstations). Zalenovic (1982) made similar observations identifying two types of production system capability in terms of their ‘design adequacy’ (which is similar to Buzacott’s ‘machine flexibility’) and ‘adaptation flexibility’ (which relates to the time it takes to change between jobs). Garrett (1986) pointed out that a flexible manufacturing system should be able to cope with ‘external disturbances’ (e.g. fluctuation in customer demand, product prices, product mix, action of competitors) and ‘internal disturbances’ (such as equipment breakdowns, variable task times, queuing delays, rejects, reworks). Slack (1983) also defined two types of flexibility, namely the range of states a system can adopt and the time (or cost) of moving from one state to another. In 1990, Sethi, A.K. and Sethi, S.P. carried out a fairly comprehensive review of the flexibility literature. This review describes eleven types of flexibility (namely machine, materials handling, operations, process, product, routing, volume, expansion, program, production and market flexibility) in terms of the purpose of each type, means of obtaining it and how it can be measured and valued. They also emphasised differences between strategic (long term), tactical (mid term) and operational flexibility (short term).

Essentially, observations made by a number of authors provide a consistent set of messages that can be applied at various levels of system granularity, i.e. with respect to individual machines or persons, groups of machines or human teams, business units, companies, enterprises, markets and so on. Also these observations made specifically about manufacturing systems are consistent with more general observations of Mandelbaum (1978) regarding the capabilities of most physical systems, namely that such systems can be pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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categorised with respect to their ‘action flexibility’ (i.e. a capability to take new actions) and ‘state flexibility’ (i.e. a capability to continue functioning despite changes in the environment). The foregoing raises two main questions about any Manufacturing Enterprise (ME), namely: (1) Is the design of the ME adequate to do the range of ‘stuff’ in hand or planned? (Essentially Zalenovic’s ‘design adequacy’, Mandelbaum’s ‘state flexibility’ and Slack’s ‘range of system states’). This main class of flexibility will be referred to as ‘change capability’ in the remainder of this paper. ‘Change capability’ in a typical ME can take two distinctive forms. One form or sub-class is concerned with ability of a ME to cope with predictable change, the other with unpredictable change. Here, respectively we are concerned with answers to two sub-questions, namely: (1.1) Can we make planned or anticipated changes quickly and effectively, e.g. to organisation structure, processes, jobs, machines, etc? (Essentially Zalenovic’s ‘adoption flexibility’ and Buzacott’s ‘job flexibility’). This sub-class of ‘change capability’ will be referred to herein as ‘programmability’. (1.2) Can we cope with unpredictable requirements and disturbances? (This includes Buzacott’s ‘machine flexibility’). This sub-class of ‘change capability’ will be referred to subsequently in this paper as ‘reactivity’ or ‘pro-activity’ dependant on the manner in which unpredictable changes are handled. (2) Is the ME designed so that it can facilitate change rapidly and effectively, for example so that we can do ‘new stuff’, or the same stuff markedly differently, or a lot more of the same stuff, in response both to planned change and to unplanned / uncertain / unpredictable requirements and environmental change? (Essentially Mandelbaum’s ‘action flexibility for uncertain change’ and Slack’s ‘cost of unpredictable systems state change’). This second main class of flexibility will be referred to subsequently as ‘change capability rate’. The foregoing provides a basis for defining the terms ‘change capability’ and ‘change capability rate’: Figure 3 summarises those definitions. Regarding (1) standard practice when designing systems is to develop models of (a) requirements and (b) systems that have capabilities that can match those requirements. In the case of ME system design there will be many, multi-level requirements and sub-systems to design and build. It follows that it will be pointless to design in flexibility at one level or into a single sub-system if others overly constrain achievable ME states. Hence a generic requirement arises to trace (or map) the effect of change through sufficiently accurate models of sub-systems to be able to detect and remove inhibitors of change. To achieve 1.1 the actual sub-systems of people, software tools, software applications and manufacturing machines will need to be sufficiently ‘programmable’ for them to cater for planned changes. Generally if a system is to be regarded as being programmable then: i) ii)

suitable means of programming the system should be known for all predictable types of change that will occur during its lifetime; the system should be so structured that its known means of programming are enabled.

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(1) Change Capability (1a) programmability: mainly to cope with predictable change includes notions of ‘design adequacy’, ‘state flexibility’ & ‘states a system can adopt’ has sub-classes of

(1b) reactivity & pro-activity: mainly to cope with un-predictable change includes notions of ‘job flexibility’ & ‘adaptation’ flexibility

(2) Change Capability Rate includes notions of engineering ‘cost’ & ‘time’ when moving between states

Figure 3 ‘Measurable’ Definitions of Flexibility In the case of planned changes therefore a programmable system should have a high ‘change capability rate’ so that job, product, shift, etc changes have minimum changeover times. Whilst to achieve 1.2 actual systems will need some in-built capability to adapt their behaviours possibly intelligently as disturbances occur as a result of yet-to-be-determined changes. Dependent on the type of unanticipated change different types of system reaction may be required. Fairly minor but unpredictable changes (such as an environmental temperature change or a material quality change) might be easily catered for in the system design, such as by including some form of sensory feedback loop to modify the system response. However, if major unpredictable change occurs, for example an existing system no longer has the required functional capability, capacity or behavioural qualities to meet modified needs or environmental conditions, then it is likely that the system composition (i.e. the resources it deploys or the way they are organised) must be radically changed. Where humans are part of a sub-system, generally the system will inherit a capability to react, but the people involved must have available to them an ‘adequate model’ of what to do and they must not be overly constrained so they cannot react. If humans are not part of the system, software processes (e.g. software ‘agents’ or whatever) may act ‘intelligently’ as surrogate humans, by analysing disturbances and using rules about what to do to modify system behaviour or even the composition of the system they operate within. If radical system change is required to match previously unforeseen ME needs, it is probable that current generation OEM solutions will lack sufficient ‘reactivity’ and/or pro-activity to rapidly and effectively determine, specify and implement necessary modifications. However in the event of unforeseen requirements change, significant potential competitive advantage may be gained relative to similar businesses by possessing adequate ‘change capability’ and ‘change capability rate’. Figure 4 illustrates this point conceptually and the fact that generally it will be necessary to invoke some form of change processes. Typically such a change process will involve system modelling (and possibly simulation) to reprogram the system (i.e. reconfigure it so that it behaves differently) or recompose the system (i.e. change its elements) so that a new set of requirements can be met. System modelling and simulation tools can be used to help enterprise personnel to make such a decision. Therefore for certain types of predictable or unpredictable change a system that is ‘change capable’ may be able to respond rapidly and cost effectively. Figure 4 conceptualises some of these issues. Clearly, however it will be impractical (for financial, social or technical reasons) for MEs to respond to all forms of unpredictable change. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Idealized Modelling Environment requirements models behavior simulation enterprise goals and objectives

process requirements

change process sub-system models sub-system goals and objectives sub-system goals and objectives sub-system goals and objectives sub-system goals and objectives sub-system structure sub-system structure sub-system structure sub-system states & structure configured set of resources configured set of resources configured set of resources configured set of resources

sub-system 1

reachable states

programmed states

change requirements

environmental disturbances system responses

Real Manufacturing Environment

Figure 4 Model-Driven Design of Flexible Systems Historically, industry has found it very hard to adapt to unforeseen (i.e. unpredictable) requirements. Two main reasons for this are (i) it is very difficult to develop good models of its complex sub-systems that can be reused to inform system change and (ii) because current means of building systems leads to real configurations of people, software and machines that are very difficult to break into. Hence making changes to the composition or structure of existing systems may not represent a practical or economic proposition. None the less we will see later that there have been significant steps made towards alleviating problems under (i) and (ii) and thereby of having an improved prospect to move rapidly and effectively from idealised environments where system models are used to determine required system change to a satisfactory realisation of those changes within operational systems. Figure 4 also indicates that gaining an understanding of ME organisation structure issues is important. There may well be structural boundaries built into existing sub-systems and between sub-systems. These built-in structures are known to be a potential source of inflexibility and can lead to unwanted collective behaviour when sub-systems interoperate. Typically these embedded structures will compromise the capability of an ME to reorganise and reallocate roles, responsibilities, jobs, tasks, etc. to related human and technical resources. Consequently the introduction of a new and inappropriate sub-systems may result in MEs not being able to reach the viable states they were designed to reach. It is also interesting to consider the importance of Slack’s observations in the context of changing MEs, as might be required as part of a major business process re-engineering exercise following a merger and formulation of a new partnership enterprise. Clearly any set of ME sub-systems will only be able to ‘reach’ a finite number of states and will incur cost and time penalties when changing between these states. Hence ME lifecycle engineering issues must also be of key concern, as they will have a major impact on the performance of the enterprise as a whole over time. This may be particularly problematic as (according to the principle of requisite variety) a higher level of intelligence is require to reason effectively about the design of a particular ME than that which exists as a constituent part of an enterprise (and therefore that available to existing enterprise personnel). None the less ‘change capability’ at various levels of an enterprise can be used as both strategic and tactical weapons if an ME can realise better response times than competitors. Consequently this illustrates a general need for MEs to develop and/or access effective pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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knowledge and skills about enterprise design and change, and to attribute capital value to them as they have the potential to provide them with competitive advantage. 3.2 A Cost of Flexibility Unfortunately flexibility is known to incur penalties, which ultimately can be equated to costs that will offset income arising from enhanced change capability. Hence, in general a balance point should be struck, where a machine is chosen or developed that has sufficient ‘change capability’ and ‘change capability rate’ to cope with likely changes that will occur during its lifetime (such as when it is used to automate certain types of activity involved in producing a family of products rather than a single product). Redundant reachable states can therefore incur cost and performance penalties but on the other hand they may still be highly beneficial particularly in uncertain environments. However, because of the uncertainty we may not be able to (a) determine with any confidence what redundant reachable states to design for, nor (b) justify additional expenditure of including additional functionality simply on the grounds of ‘future proofing’.

4. Illustration of the Change Capability and Change Capability Rate of Commercial Robotic Systems 4.1 Alternative Robot Systems and their Constrained Reachable States Since the mid 1960s many robot systems have been developed and supported in the field by OEM suppliers of manufacturing industries world-wide. Such systems can be differentiated in various ways in terms of their: manipulation configuration; embedded drives and sensors; controllers; and workplace support elements. Figure 5 shows some common manipulator and end effecter configuration, while Figure 6 illustrates alternative drive and sensory technologies that robots commonly deploy. Robot control system technology has advanced significantly in recent decades, particularly with respect to the way in which and ease with which (1) their associated manipulator, end effectors and workplace elements can be programmed offline, and/or via ‘teaching’ facilities, and (2) the way in which robot controllers can be interfaced to other elements of manufacturing systems. alpha

Y

Z

Z

3L

1L,2R

theta

X

POLAR

CARTESIAN alpha

Y

3R

beta

Z

2L,1R

3R

EXAMPLE END EFFECTER CONFIGURATION

theta CYLINDRICAL

theta REVOLUTE

Figure 5 Common robot configurations

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Irrespective of such developments, however, inherently any given robotic system will have a constrained set of reachable states that, as illustrated by Figure 7, will lie within a particular working envelop, which is determined by specifics of the robot manipulator configuration. The accuracy and repeatability with which robot manipulators and end effect systems can be programmed to attain positional states will be dependent on characteristics of (a) the types and specific cases of drive system deployed, (b) the sensing (e.g. positioning) devices used and (c) the types and specific cases of control system used. For example a state of the art electric servo driven robot and control system may be able to be programmed to position its end effecter with a repeatability of 10 µm in an envelop of 3m3. When used as part of a fully engineered and installed robotic system, such an electric servo driven robot may be equipped with a range of tools. This might be for one or more of the following: drilling, milling, spot or arc welding, or for machine feeding or palletising. Also facilities might have been provided to program tool selection, operational sequences and even motion path control. It follows that such an engineered robotic system will have many (possibly order of 108) viable programmable states which can be selected as long as they tie within the working envelop (or design adequacy) of the particular robot system. COMMON DRIVES

COMMON FEEDBACK ELEMENTS

ia

DC motor

Revolvers

if

analogue Potentiometers

Electric drives stepper motor

Encoders

omega

digital

Vision systems

cylinders

oil

Hydraulic drives

COMMON TRANSMISSION ELEMENTS

rotary motor

pa cylinders Pneumatic drives

pb Lead-screws

Gears

Ratchets

Clutches

air

rotary motor

Figure 6 Common robot drive, feedback and transmission elements

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working envelop

state a state b

Figure 7 Constraint reachable states of robots By contrast, it may only be possible to program a three-axis pneumatic robot to reach 8 (23) programmable states, which correspond to end stop positions located within the robots working envelop. Yet this might prove to be a viable OEM solution still with sufficient flexibility and accuracy for the range of jobs in hand; where for example an operator might mechanically adjust the end stop positions when a dimensionally different batch of products, within a given product family, needs to be manipulated. The foregoing contrasts in terms of potential reachable states between (typically higher cost) servo driven robots and simpler end stop robots. Also comparison drawn between these two types of robot shows a significant contrast in change capability via programmability. But if such a limited range of viable states is all that is required for a purpose during its useful lifetime then the choice of pneumatic solution might be more effective on grounds of reduced technical/programming and possibly because it can achieve faster workpiece positioning. This also serves to illustrate notions about change capability rate. The reader might observe that an end-stop robot can also be engineered to reach all states within its working envelop. But this will require human engineering effort; and therefore costs will be incurred (at say set up time) in respect of human resource costs and set up delays. This essentially illustrates a simple form of robot system reconfiguration; namely a response made by an operator or engineer which involves modifying the programmable system so that it can reach new states for the new positioning tasks at hand. However in this case it may be that the pneumatic robot positioning system might possess a better effective ‘power to weight ratio’, such that during its normally programmed operation work pieces or tools can be manipulated faster than with a multi-axis servo driven robot solution. Here it is pointed out that for all of the common manipulation configurations shown in Figure 5, one or more robot axes are physically driven by other mechanically coupled robot axes. This in general will mean that the robot manipulator systems concerned will need not only to position the loads placed on them (such as by needed work pieces and tools) but will also need to bear loads from the manipulator itself and its end effecter. As a consequence the ‘change capability rate’ will deteriorate such that either the achievable speed or the programmable positioning accuracy will be reduced. The foregoing illustrates that: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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A) If a robot manipulator, actuator and sensor, control systems and work place element configuration is well matched to a known set of programmable tasks in hand (i.e. if the rate at which those tasks occur and the timeframe over which they occur is appropriate) then it can prove a technically viable and possibly cost effective solution. B) If a given set of programmable tasks are uncertain but essentially align with reachable states of a given robotic system then this system could well prove to provide an effective production system building block. This is particularly true because its programmability characteristics can in the right circumstances enable economy of scope production, and to some extent economy of scale production. However a general purpose robotic system will likely perform tasks significantly more slowly than would a specially designed manipulator, actuator and sensor system; but the latter could well not have sufficient programmability to cope with the product scope involved. C) When during the lifetime of a robot system the task requirements change (unpredictably) and give rise to programmable manipulation outside the working envelop of that system, then most likely significant robot system reconfiguration (and hence engineering effort and cost) will be required. 4.2 Common Industrial Applications of Robot Systems Over the last three decades industry has used robotic systems for a variety of product realising applications. Common examples of these are listed in Table 2. Typically robots are equipped with specialist tools and related application systems such as workplace sensors, tools and positioning. Table 3 gives example end effector tools here. In general this makes the robot system more special purpose and constrains its useful reachable states. For example an electronic assembly robot system based on the use of an Adept Scara robot arm is very effective when tooled up and fitted with component feeders and sensors for pcb assembly but it is not at all well suited to spot welding of panel joints on moving car bodies. Table 2 Common Industrial Applications of Robots General Application Class

Example Application

Sensing / Testing

Welding Forging Machining Feeding / Off Loading Palletising General Engineering Electronic Products Automotive Nuclear

Mining

Excavation

Processing Handling / Positioning Assembly

Case of Application / Object Spot Arc Welding, Drilling and Roughing Parts Loading machine tools and presses. Packaging and warehousing. Small batch assembly of white goods, pcb’s and electric products Leak testing of cars and nuclear power stations, testing earth for raw materials Deep seam mining

Table 3 Example End Effector Tools Micro manipulators Mechanical grippers Massive steel hands Hooking mechanisms Electro magnets Vacuum cups pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Sticky fingers / adhesives Quick disconnect bayonet sockets

4.3 Need for Configurable Robotic Systems: Role of Mechatronics and Component and Modelling Technologies Suppose that some product dynamic gives rise to production requirements change which impacts on an installed robotic system so that those requirements lie outside of either or both of its (1) reachable states or (2) its processing capacity. In such a situation some form of production system reconfiguration will be essential. It could be that the installed robotic system is decommissioned or replaced or it could be upgraded. Generally despite recent technology advances that allow robots to be more readily integrated into wider scope production systems, those systems remain lacking in their available support for production systems redesign and reengineering. Figure 8 illustrates the kinds of reconfiguration problems involved. Here it is supposed that a critical dimension of a product type which is being assembled has been changed in response to some new (unexpected) customer requirement, so that the robot system can no longer complete a required positioning operation. One configurational change might be to introduce a new workpiece positioner to achieve relative movement between the robot and the workpiece. In general though this will require mechanical, control system and sensory system redesign and the purchase, followed by installation of mechanical and electrical hardware and system software integration, reprogramming and interoperation. This kind of systems engineering effort might take many months to achieve and would likely cost many tens of thousand pounds sterling. It could even result in system reengineering costs that are greater than the original system engineering costs. The foregoing illustrates that current OEM robotic solutions may well be change capable in respect of their ability to be programmed (within the design adequacy of the robotic system as a whole) to cope with product variance in respect to: dimensional change (product dynamic type 1) as defined in section 1; change in production mix (product dynamic type 3) which is allied to achieving economy of scope; and to facilitate aspects of new product introduction (product dynamic type 4). However the inherent programmability afforded is not particularly suited to coping with production volume change (product dynamic type 2). The robot is a ‘generalist machine’ rather than a ‘specialist machine’; hence unless its manipulated kinematics and dynamics are particularly well suited to the task at hand a robot system solution will likely be slow (relative to a specially designed machine) and hence can only cope with limited production volumes, such that opportunities to realise economies of scale will be limited. Furthermore from the discussion about Figure 8 it is evident that the occurrence of any type of product dynamic that requires the robot to perform outside of its design adequacy will likely result in long delays when reengineering the robot system. Such reengineering will be needed so that the new robot system can possess a capability to reach all new positional states required.

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sensors work-pieces

Figure 8 Conventional robot system engineering to extend the reachable states The preceding discussion illustrates a design rationale for the creation of a new generation of highly reconfigurable, component-based machine systems; where the components are readily reprogrammable; where components can be flexibly structured together such that they can form many different manipulator configurations from selected groupings of mechatronic components, such that created manipulation systems can function with high speed and accuracy; and where those components can be reconfigured, possibly complemented or replaced by other components (see Figure 9) into new high speed and accurate manipulator systems when uncertain changes in product dynamic occur. computational element

sensors

computational element

electro-mechanical elements computational element

computational element computational element

computer infrastructure

Figure 9 Mechatronic robot system engineering

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select & program component behaviours

+

will result in

define & program system structure and behaviours

a composed system

re-select & re-program component behaviours

+

will result in

re-define & re-program system structure and behaviours

a re-composed (or changed) system

Figure 10 Component based system engineering Figure 9 shows conceptually how such reconfigurable manipulator systems can be created based on use of mechatronic components. These reusable building blocks of configurable manipulator systems comprise software, computer hardware, electromechanical drive elements and sensory elements which share information and interact via use of infrastructural services run over real-time local area network technology. The approach enables the components to be physically distributed from each other and/or some of their controlling, monitoring and management elements whilst enabling rapid reprogramming and reconfiguration. Figure 10 shows conceptually how different selections of reusable mechatronic components can be structured together so that they perform as an integral manipulator system which might comprise say 2 to many tens of servo driven axis of motion; some motions realising tasks in parallel, others working in groups to achieve complex motion paths, others carrying out sequential tasks. In principle as indicated by Figure 11, this kind of mechatronic system can match high performance characteristics of special purpose machines whilst also supporting the programmability of robotic systems. In addition rapid reconfiguration can lead fairly rapidly and with effective levels of reengineering to new distributed, servo controlled manipulator designs in the event of product dynamics that is outside the original design adequacy of an existing component-based manipulator system.

flexibility

can increase responsiveness to uncertainty e.g. unpredictable requirements composable and programmable system programmable system

performance Figure 11 Cost of flexibility in term of reduced performance - can be offset through use of component based systems pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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4.3 Need for Virtual Engineering Environments To facilitate the life cycle engineering of reconfigurable mechatronic manipulator systems, a unified set of virtual engineer software tools is required. Such a set of tools is illustrated by Figure 12 and its use is being developed and tested by CECA researchers at Loughborough University. This toolset brings together models of products, processes, people and machines related to the design, implementation and ongoing programming and reconfiguration of production systems capable of coping with predictable and unpredictable product dynamics of types 1) to 4). As illustrated conceptually by Figure 12, three prime keys to the use of this virtual engineering toolset are: (I)

Use of enterprise modelling to provide modelling formalisms that are needed to cope with the high levels of complexity involved when capturing enduring characteristics of the business and engineering environments in which a given reconfigurable production system will be used; thereby providing a well defined context for production systems modelling Real World

Ideal World

suppliers customers

Enterprise & business environment modelling

competitors

product dynamic

Process & value stream modelling

Workstation modelling

Product engineering (CAD/CAM)

People modelling

Model of assembly system & its business environment Product design (CAD)

stakeholders

technologies

Machine modelling Integrated information modelling

IT systems modelling

Control systems modelling

government

used to experiment, understand, predict & inform policy & production systems re-design & reengineering

Figure 12 Virtual engineering of responsive production systems (II)

(III)

Use of a Product Lifecycle Management (PLM) software platform to manage coherent access to actual product, process, people and machine data and models pertaining to a given ME and its production systems, and Use of various simulation tools including discrete event and continuous simulators that computer execute and animate models of workloaded production lines and production workstations and their related machine and people systems; thereby enabling the selection and matching of suitable manufacturing philosophies, methods, tools and OEM solutions, examples of which are listed in Table 1.

Use of one such simulation tool will be illustrated during the conference presentation. This is a proprietary tool called Delmia which enables simulated motion of alternative manipulator kinematics and facilities related programming of motion profiles, sequences and control and sensory system elements. The conference presentation will show how such a simulation tool supports the design and computer animation of a component-based, special purpose distributed machine.

5. Conclusions and Reflections This paper has described how mechatronic and virtual engineering technologies are emerging that can underpin the development and application of a new generation of change capable machines. It explains how pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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four types of product dynamic can impact in terms of change capability requirements on robot systems. This provides a qualitative basis for deciding if any robot system can function effectively in a given production environment. Also described is how an integrated set of virtual engineering software tools can provide systematic and quantitative support for the lifecycle engineering of robot-like automated systems. Those tools create distributed, component-based machines that are readily programmable and reconfigurable and can function with speed and accuracy, so as to provide next generation means of engineering a new breed of responsive production systems.

6. Acknowledgements The author wishes to fully acknowledge the significant contributions to knowledge and understanding made by his colleagues and students in MSI and CECA, on which the concepts and findings reported herein are based.

7. References Angra, S. et al., 2008, Cellular Manufacturing-A time based analysis to the layout problem. Int. J. Production Economies 112 (2008) 427-438. Buzacott J A. The Fundamental Principles of Flexibility in Manufacturing Systems, Proceedings of 1st International Conference on FMS, Brighton, UK, 20-22 October 1982, pp 13-22. Cui Z & Weston R.H., Model Driven Engineering of Economy of Scope Systems, International Conference on Advanced Design And Manufacture, Jan 2008, Haikou/Sanya, China. Garrett, S.E., “Strategy First: a case in FMS justification”, in K. E. Stecke and R Suri (Eds.), Proceeding of the second ORSA/TIMS Conference on FMS; Operations Research Models and Application, Amsterdam: Elsevier Science Publishers, 1986, pp. 17-29. Ian, Christian. Et al. Agile Manufacturing Transitional Strategies, Manufacturing Information Systems: Proceedings of the Fourth SME International Conference. Ittner, CD and Larcker, DF (1995) Total quality management and the choice of information and reward systems, Journal of Accounting Research 33(suppl.), pp. 1-34. Koren, Y. et al., 1999, Reconfigurable Manufacturing Systems, Annal of the CIRP Vol. 48/2 1999. Loe N. (1998), Postponement for mass Customisation, Chapter 5, in Gattorn J; Strategic Supply Chain Alignment, Gower. Mandelbaum M. Flexibility in Decision Making: An Exploration and Unification. PhD Thesis, Dept. of Industrial Engineering, University of Toronto, Ontario, 1978. Mason-Jones R, Naylor J B, Towill D R. (2000), Engineering the Leagile Supply chain, International Journal of Agile Manufacturing System. Vol 2, No.1, pp54-61. Sethi, A.K. and Sethi, S.P., “Flexibility in manufacturing: A Survey”, International Journal of Flexible Manufacturing Systems, Vol. 2, No. 4, 1990, pp. 289-328 Slack, N., “Flexibility as a manufacturing objective”, International Journal of Operations and Production Management, Vol. 3, No. 3, 1983, pp. 4-13. Smith R P, Barton R, Nowack C, Zayas-Castro J L., Concurrent Engineering: A Partnership Approach, Proceedings of 1996 ASEE Annual Meeting, Washington DC, June 1996 Suda, H., "Future Factory System Formulated in Japan," Parts 1 and 2, Techno Japan, Part 1: Vol. 22, No. 10, Oct 1989, 15-25; Part 2: Vol. 23, No. 3, March 1990, 51-61. Suresh, N.C. & Kay, J. 1998, Group Technology and Cellular Manufacturing: Updated Perspectives, Group Technology and Cellular Manufacturing- A state-of-the-art synthesis of research and practice, A, pp.1-14.

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Womack, James P., Jones, Daniel T., and Roos, Daniel (1991), The Machine That Changed the World: The Story of Lean Production, Harper Business Yasuhiro M (1998), Toyota Production System, An Integrated Approach to Just-In-Time, Third edition, Norcross, GA: Engineering & Management Press. Zalenovic D M. Flexibility – A Condition for Effective Production Systems, International Journal of Production Research, Vol. 20, No. 3, 1982, pp 319-337.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

TECHNICAL SESSION 1A: CAPACITY BUILDING IN ENGINEERING R & D

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(ICERD 08002) DESIGNING ARCHITECT’S BRIEF FOR A FACULTY OF ENGINEERING

2

MT Oladiran1 and J. Foster2 1 University of Botswana, Faculty of Engineering and Technology P/Bag 0061, Gaborone. Botswana Email: [email protected] Carlisle College, Victoria Place, Carlisle, Cumbria, U.K.

Abstract: A team of academics produced a Design Brief (DB) to assist architects design a scholarly physical environment for modern engineering education and research. The information gathered from external and internal sources was used to define important themes that the buildings should reflect and hence to arrive at a list of the required spaces. Critical internal and external reviews and budget constraints led to a series of successive refinements of the DB. A design competition was organised for all interested architects in the country to select the architect for the project and consolation prizes were awarded to second and third finalists. The planned development will provide 17900 m2 and 25200 m2 net usable space and estimated gross building area respectively. 1. Introduction In 1996 the former Botswana Polytechnic was incorporated into the University of Botswana (UB) as the Faculty of Engineering and Technology (FET). The Polytechnic was located on the east and west campuses that are about 1.7 km away from the main UB campus where a new facility would be built. The Faculty will consist of a Mining Centre and 5 academic departments, namely, Architecture & Planning, Civil Engineering, Electrical Engineering, Mechanical Engineering and Industrial Design and Technology. The specifications for earlier projects of the UB had largely been prepared by the office of its Physical/ Institutional Planning, often with the assistance of external consultants. However the planning of buildings for FET presented a clear opportunity to involve faculty professional expertise in planning, design, architecture, information technology and engineering. The University assigned a team of its staff the task of producing the Design Brief (DB) for the new facility. The DB is essentially a statement of the requirements of the University to guide the actual design process. Under the guidance of the Dean, the Design Team (DT) members included at least one member from each of the departments and others selected to provide a range of expertise. A committee consisting of all heads of the cognate departments and the Dean reviewed the work of the DT regularly. The DT consulted both staff and students to discover their aspirations for the new buildings, and their experiences of other engineering facilities. Simultaneously, the team consulted architects locally, regionally and internationally. Also the DT visited some engineering and architecture faculties in the region to assess their buildings and learning environment. There was active correspondence with the University of Colorado, Washington State University, and De Montfort University, all of which had been identified as having constructed innovative facilities in recent years. The DB was prepared in recognition that the degrees will seek accreditation by appropriate international professional agencies or organizations whose requirements are usually stringent in terms of space for laboratory, teaching, workshops, research, staffing offices etc. The use of space and facilities in the DB was rationalized. For example, one control and instrumentation laboratory was provided to serve both Electrical and Mechanical Engineering departments. Technological development is changing rapidly and this will certainly affect the type and mode of engineering learning environment. However, the growing importance of online teaching and digital scholarship will assume new proportions due to the growing availability of Internet applications (Refs 1-4). As online teaching requires sufficient internet connectivity, some of the classrooms and laboratories will be pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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provided with computers, internet facility and projectors so that students can interact with the lecturer. This will be desired as Distance Education and Open Learning progress to new heights at the University (Refs 57). 2. Scope of the Project 2.1 Site The building site occupies an area of approximately 2.5 ha. Two notable constraints on the positioning of the buildings are 1) the presence of a City Council sewer line, which crosses the site centrally from north to south and 2) a central linear landscaped open space to be created across the site from east to west, in order to provide a clear line of view between the library and a proposed multi purpose hall. 2.2 Planning Period The planning period considered for the facility is 15 years. During this time, substantial changes may be expected not only in the structure and functions of the University, but also in technology. There is a clear need for design solutions that promote flexible use and adaptation. Also, space was set aside for future expansion. 2.3 Departments The buildings are to accommodate those disciplines that FET firmly expects to offer during the planning period. It is not possible, however, to predict departmental divisions to be adopted throughout the life of the building. As departments are not static in size or function, it must be possible to regroup and adapt the use of spaces within the buildings, as academic organisation and programmes change. 2.4 Planned Programmes and Enrolment Numbers Detailed prediction of the relative or absolute full time equivalent (FTE) student numbers in each programme is likely to be wrong both in terms of numbers and in subject definition. Therefore a simple equal FTE numbers was assumed in several departments. This simplification does not expect all departments to have equal numbers of students. It serves as a starting point for calculating a reasonable target for total FTE students, and for indicating a likely number of programmes and classes. Some programmes may be considered as temporary surrogates for programmes that will be developed as modes of instructional delivery and subject demands change. From the total estimated FTE, the number and size of lecture rooms required, and of the number of staff and research offices were obtained. Other space requirements were based on subject specialisms. Specialised laboratories for the present portfolio of subjects were used as the basis for calculating the laboratory and workshop space. FTE for master’s students was assumed to be one and a half times FTE for undergraduate students. Table 1 shows the notional capacities of the full-time programmes. In addition effective numbers will be increased by  Short courses (continuing professional development, largely at graduate engineer level)  Part time access to existing full-time and special part-time study programmes  Distance learning modes of study and  Doctoral students. Table 1. Programme

Programmes and Notional Numbers Duration Enrolment (y) Per year

B.Eng.(Civil) M.Sc.(Civil) B.Eng.(Electrical&El) M.Sc.(Electrical&El) B.Eng.(Mechanical) M.Sc.(Mechanical) B.Design

4* 2 4* 2 4* 2 4*

50 10 50 10 50 10 60

No of Students in Full time Faculty at one Equivalent Time (FTE) by dept. 200 20 230 Civil 200 20 230 Elec. 200 20 230 Mech. 240

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria M.Des. 2 10 B.Sc. (Planning) 4 20 M.Sc.(Planning) 2 10 B.Architecture 5 20 M.Architecture 2 10 Mining Dip. 2 25 Inter-University B. 1* 15 Mining Faculty Total Capacity * excludes 1 year of study in the Faculty of Science

20 80 20 100 20 50 15

270 IDT

1205

1265

58

240 Arch+Pl 65 Mining

2.5 Cost The original project cost of about P70 m was approved about 10 years ago and increased to P110 about 4 years ago ($1 ≈ P6). Inflation and decreasing exchange rate of the currency implies that the facility to be procured today may not be equivalent to the initial concept. 3.

Themes of the Design Brief

The DB emphasises the following themes: 3.1 Energy Efficiency and Resource Conservation Requirements for low-energy and optimal use of rainfall catchment over the building surfaced area were included in the DB. This principle would not only exist in the design, but also be demonstrable to students. For example, part of the building and services would be available for monitoring and testing during normal occupancy. 3.2 Information Technology Increasing use of computers as teaching tools can materially affect space requirements. The Brief was written to guide the designer to provide for information technology as supplying the primary teaching tools for all FET subjects. Sufficient terminals were incorporated to allow each student to use a computer up to 5h per 24 hour period. Also some classrooms may be convertible to full computer-based configuration as methods of instructional delivery during the life of the buildings. 3.3 Flexibility Flexibility of use has been emphasised at appropriate points in the Brief. The teaching space will be modular for effective space utilization. 3.4 Integration The engineering facility will be embedded with the existing and future development of the University where it will be located. The buildings will promote aesthetic appearance of the University.

3.5 Maintainability The materials should be selected to ensure durability and low maintenance. The building envelope may be of brick walls that will not require painting finishes or regular attention. 4. Space Allocation The majority of class sizes would continue to be less than 100 students. Only the common courses in the second year are likely to require lectures to about 225 students. Accordingly, one auditorium for an audience of 250 persons, with the normal projection and public address facilities is required. The requirements for rooms were estimated being aware that the larger rooms are more versatile. In many engineering departments the Staff : Student Ratio (SSR) varied between 1:8, and 1:18. In this case, a ratio of 1:10 ratio was assumed to calculate the number of academic offices per department. Sufficient instructors’ and technicians’ offices have been provided. The number of technicians was assumed at a ratio pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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of 2 :3 with academic staff. Many technicians will be accommodated in shared offices. Table 2 gives a breakdown of usable space within which rooms may be easily reconfigured for new uses. Table 2. Classification of Usable Space Type Description Area (m2) 1 Information Technology-based 1,300 spaces 2 Lecture and Tutorial Rooms 1,300 3 Studios and light Laboratories 5,200 4 Heavy Laboratories and Workshops 6,700 5 Offices, Meeting Rooms and 3,400 Ancillary Total =Net Usable Space (NUS) 17,900 Gross Building Area (=1.4*NUS) 25,200 As research activities are critical to developing and maintaining regional and world-wide recognition for excellence, staff will participate actively in research, consultancies and innovative studies. In this regard, collaboration will be forged with other institutions either in the region or elsewhere. Also linkages will be fostered with industry, companies and government. A faculty-based, fully-fledged Technology Assessment/Development Unit will be required for liaison with other bodies and also to take care of industrial attachments. 5. Review by External Assessors The FET design brief is the most detailed building specification that the UB has ever prepared for its architects. Two external engineering professors reviewed the academic requirements reflected in the brief, while a campus design architect reviewed the architectural parameters. Their reports recommended the DB to the University. 6. Architects Competition A design competition was promoted to provide the University with a wide choice of architectural design solutions to the requirements of the brief. The competition was in two stages. The first stage was open to all professional architects with permanent offices in Botswana. The second stage was restricted to those architects who were estimated to possess the capability to complete the design project. The competitors admitted to the second stage presented an outline design for buildings and open spaces within the requirements of the DB. The presentation was in form of drawings, sketches, photographs, a model, and a report. They further demonstrated how their designs would meet the requirements of the client, within the stated budget constraint. A jury assessed the entries on the basis of how well the design will meet the requirements made explicit in the DB. The matrix of the scoring criteria is presented in Table 3. The winner of the second stage of the competition was commissioned as the Architect for the project. The elevation of the winning design as produced by the external assessor is depicted in Figure 1. The second and third competitors were awarded monetary prizes.

Table 3 Matrix of Scoring Criteria for Design Competition Criterion Questions Source Data 1. Completeness of the Is there sufficient detail to show the location design (i.e. Provision of and dimensions of all the listed spaces in the Drawings and the Space Requirements Design Brief (DB) and necessary ancillaries? Report in the Design Brief Are the requirements of the various types of space listed in the DB adequately provided for at this stage of the design? pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria 3. Organization of Space (i.e. Quality of Circulation and Communal Spaces) 4. Informal and Outside Areas, and Parking (i.e. Site Planning and External Spaces) 5. Safety and Security (i.e. are the number of exits etc. adequate) 6. Attention to detail (i.e. attention to Services, Constructability and Maintainability)

7. Energy and Resource Efficiency

8. Campus and future relationships (i.e. .Relationship to Existing Buildings and. Expandability of facility)

9. Image and aesthetics (i.e. Aesthetic Appeal)

10. Cost Analysis (i.e. Value for Money) 11. Material Selection

How well does the design provide for working relationships, movements of people, control of noise? How appropriate is the design of corridors, room access, etc. Do the informal areas provide suitable places for social interaction and relaxation? Have the required on-site 125 parking spaces been suitably positioned? How well does the design address the safety and security issues? Can the units be accessed by emergency vehicles? Provision at the outline design stage for lifts and stairways, toilets, delivery access, waste disposal, instrumentation and artwork. Are the issues of constructability and maintainability of the facility being addressed properly? Is there good use of natural/day lighting? Is there provision for natural ventilation? Will the outline design achieve good energy management? Is the design environmentally conscious? How well does the design handle movements of students, staff and visitors? How well is it integrated with nearby buildings such as the UB Library in terms of form and function? Is future expansion clearly provided for, and will it be possible to construct future buildings with minimal disruption? Will the design succeed in projecting a vibrant image of Engineering and Architecture? How attractive is the environment being created? Has there been a serious attempt to analyse likely costs? Have low-priced solutions been adopted? Are the materials appropriate to Botswana Society and & climate? Are they durable?

60

Model, drawings report

and

Drawings, model report

and

Drawings report

and

Drawings, model report

and

Report, drawings model

and

Model, drawings report

and

Model drawings

and

Report Drawing Report

and

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 1.

Notional Elevation of Facility

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7. Conclusion The University of Botswana has approved a project during the current planning period with the aim of creating new facilities for its Faculty of Engineering and Technology. A learner-focused scholarly environment will ensure that the engineering graduates are adequately prepared for the work place. The DB included provision for state-of-the-art computing resources and space for hands on experimental investigations As future research, teaching and learning directions cannot be completely predicted in engineering and ICT developments, the FET facility will be flexible with abundant space for expansion. This DB must be seen as an initial input from the Faculty. A continuous consultation involving FET with the designer, consultants and contractors will be required at various stages to ensure that the final building satisfies the aspirations of the faculty and students. The DB was highly recommended by the external reviewers and the process of producing the DB has enriched experience of the academic staff in the faculty. It is envisioned that the building of the facility will be completed and commissioned in 2010. 8.

References

[1] M. Eisenberg, Internet-based Engineering Education on Sustainability in Global Engineering Teams, Proceedings of the 4th Global Conference on Sustainable Product Development and Life Cycle Engineering, Brazil, 2006 [2] G. Farrell and S. Isaacs, Survey of ICT and Education in Africa: A summary report Based on 53 Country Surveys. Washington D.C. Info Dev./World Bank, 2007. [3] A. Bargelis, R. Mankute, and D. Cikotiene. Web-based Learning in Engineering and Management Education: an IIDSP for Teaching of Inter-disciplinary Study Modules. Int. J. Engng Ed., 23 (2), 378-386, 2007. [4] B.H. Khan (Ed.). Web-based instruction. Englewood Cliffs: Educational Technology Publications, (1997). [5] A.P Shemi and J. Khengere, Prospects for Digital Scholarship through Mobile learning in Higher Education: The Case of University of Botswana. Conference of Digital Scholarship and the University of Botswana, December 2007. [6] G. S. Ntloedibe-Kuswani, A preliminary Cost-Effectiveness Analysis of extending access through the utilization of Information and Communication Technology at the University of Botswana. Conference of Digital Scholarship and the University of Botswana, December 2007. [7] S.O Ojo and A. Masizana-Katongo, A Framework for harnessing the potentials of Grid Computing as an enabler of Digital Scholarship in an African University Context, Conference of Digital Scholarship and the University of Botswana, December 2007.

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(ICERD 08003) Experiential Learning Centre for Electronic Engineering Students through partnerships and collaboration (Summary) SJ Jacobs Faculty of Engineering and the Built Environment, Tshwane University of Technology, South Africa, [email protected] Author for correspondence: SJ Jacobs FAO Otieno Faculty of Engineering and the Built Environment, Tshwane University of Technology, South Africa, [email protected] Abstract In South Africa, one of the factors influencing the rate at which technicians and engineers are trained is the low throughputs of the Universities. Therefore this paper presents an approach or mechanism towards reducing the number of drop outs and enabling students to complete their studies in a shorter period of time, improve the completion rate, encourage students to undertake further studies and research activities through partnerships and collaboration. This intervention will enable the students to complete their studies in the minimum period of time Key words: Partnerships, collaboration, experiential training, experiential training infrastructure, training material, student throughput. Introduction and Orientation Among the factors influencing the rate at which technicians and Engineers are trained, is the low throughput of the Universities. Therefore working toward reducing the number of drop-outs and enabling student to complete their studies in shorter periods of time can greatly improve the completion rate and encourage students to undertake further studies and research activities. Students from the Faculties of Engineering at all the Universities of Technology in South Africa need to complete a full year of practical training before being awarded their diploma or degree and the training is not provided by these institutions. Industries were the biggest providers of practical training to students, but now with the increased demand they are not able to accommodate all the students, therefore many students are not able to complete their studies and obtain their diplomas or degrees. Furthermore, the Engineering Council of South Africa (ECSA) has required that the practical training be an accredited learning program to be completed instead of a job or a position in a company, which in most cases is not in line with the course or the degree being studied for. Developing practical training centres with accredited programs within Universities of Technology will be an appropriate approach toward solving these problems. On one hand, this will meet ECSA requirements with specialized training programs, well oriented and of a high standard. On the other hand, it will increase the number of graduates at Universities of Technology, providing more qualified Technicians and Engineers to industries. Rationale The implementation of a high standard Experiential Learning Centre within the Tshwane University of Technology (in South Africa) in collaboration with Small Medium and Micro Enterprises (SMMEs) as well as a number of other industrial partners (national and international) holds a great potential in increasing the institution current rate of producing electronic technicians and Engineers. Providing the practical training on campus, through partnerships and collaboration, assist in standardizing the training and ensuring that all students receive the same kind of relevant and quality training. Partnerships a Collaboration

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The Faculty of Engineering and the Built Environment at the Tshwane University of Technology (TUT), is a key player in providing the high-level human resources and research and innovation outputs to fuel South Africa’s developing economy. The main aim and mission is to educate and train students for the world of work. As a Faculty we strive for excellence - excellence in terms of knowledge, in terms of skills, in terms of achievement rather than percentages – and in terms of service delivery and participation. With its enhanced focus on applied research and development, the Faculty of Engineering and the Built Environment extends the parameters of technological innovation by making knowledge useful in service of its stakeholders and the greater South African community. The applied research and development has to comply with international standards to make a credible contribution to Southern African society. In exploring new avenues of research and development (supported by initiatives like F’SATIE - French, GTZ - German and Tshumisano – South Africa), the Faculty of Engineering and the Built Environment is committed to the highest quality. The French South African Technical Institute in Electronics (F’SATIE) is a multinational initiative that was initiated in South Africa to stimulate electronics research and development in the country. The Department of Science and Technology (DST) of South Africa initiated the Technology Stations Programme (TSP) to create support for SMMEs in targeted business sectors. Tshumisano Trust, which means cooperation or partnership (Tshumisano, 2007), was established in 2002 by the DST as a joint venture between government, the German Agency for Technical Cooperation (GTZ) and the Committee of Technikon Principals (CTP), with the mandate to provide support for the SME sector through its TSP. As part of the fulfilment of this mandate the Technology Station in Electronics (TSE) was established at Tshwane University of Technology (TUT) with the primary focus to operate in the electronic, electrical and information and communication technology (ICT) industries. Problem Statement The main challenge is to align current experiential training activities within the Experiential Learning Centre (electrical/electronics discipline) to the industry and academic requirements of qualifications offered at the Faculty of Engineering. The Experiential Learning Centre initiative form part of the Faculty Innovation Centre (FIC) at the Faculty of Engineering, responsible for the experiential training component of the National Diploma and Bachelor in Technology (B Tech) qualifications as well as presenting short learning programmes to industry. One of the contributing factors in having a practical training centre on campus are that the National Diploma Courses is offered full-time over a three year period consist of (1) practical component and a (2) theoretical component. Infrastructure and Competent Human Resources The Centre has clearly defined service offerings linked to proper infrastructure and competent human resources to deliver on the mandate of this initiative. Adequate premises, infrastructure, human resources, service offerings, systems and controls as well as partnerships and collaboration form part of the necessary components for a successful Experiential Learning Centre. Therefore, the operational plan of the Centre has clear measurables where the competence and capacity is linked to outputs (deliverables). Experiential Training to support Student Throughput Rate The Experiential Learning Centre provides training to students on campus, has its own dedicated laboratories and makes use of lecturers and experts from the university, F’SATIE, on-campus SMME, TSE and other external companies. There are three main activities through each semester, which activities are listed below:  Administration and Marketing  Students recruitment and selection  Courses and practical’s delivery The other activities are the selection of lecturers, training material review, purchase and distribution of components and training tools and quality control.

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The training offered currently is mainly in the field of electronics. The main activities being carried out during a semester are (1) Engineers and experts from industry, (2) Lecturers from TUT, (3) TSE Staff and (4) F’SATIE Staff. Hundreds of students apply annually to do experiential training or work integrated learning, which forms part of the qualification, and only a few get accepted. Summary and Conclusion The mission of TUT is to be committed to the development of higher education through: 1) Teaching and Learning:  To achieve excellence in teaching and learning endeavours by developing entrepreneurial, technological and cognitive skills;  To create an environment conducive to develop behavioural, attitudinal competencies and social skills through cultural, sporting and personal development activities. 2) Research:  To generate innovative and relevant research. 3) Community Service:  To create a culture of life-long learning.  To empower our communities, by sharing knowledge, skills and resources. All these functions will be enhanced by national and international partnerships in order to meet the needs of stakeholders of a democratic society. Therefore, the purpose with the establishment of the Work Integrated Learning Centre at TUT is to create a dynamic Centre of Technology training in which TUT aims to be a leader in its field, with high standards of quality and performance comparable to the best institutions in the world, to continuously innovate and advance the frontiers of science and technology and to be a source of inspiration for others. List of References Department of Science & Technology (DST). 2006a. Annual report 2005/6. South Africa. Department of Science & Technology (DST). 2006b. Corporate strategy second year edition (2006/7) 2005/6-2008/9. South Africa. Engineering Council of South Africa (ECSA). 2007. [Online]. Available at: www.ecsa.org.za. Accessed: 28/11/07 Jacobs, SJ. 2007. Technology Station in Electronics (TSE) annual report 2006/7. (Unpublished). Jacobs, S.J. and Herselman, M.E. 2007. Tshwane University of Technology and the Technology Station in Electronics strengthening technological innovation activities amongst SMEs and students. (Submitted for publication). Prinsloo G. and Hattingh A.G. 2006. French SA Institute (F’Satie) ON THE VUT CAMPUS TO STIMULATE ELECTRONICS MANUFACTURING. (Unpublished). Vukuzenzela, 2006. JIPSA on the Fast Track. Volume 1 (1), May 2006 [Online]. Available at: http://www.info.gov.za/vukuzenzele/Pages/jipsa(1).htm Accessed: 24/05/07 Mlambo-Ngcuka, P. (2006). Launch of the Joint Initiative for Priority Skills Acquisition (JIPSA). [Online]. Available at: www.info.gov.za/speeches/. Accessed: 24/05/07 South Africa Info, 2007a. ICT and Electronics in South Africa. [Online]. Available at: http://www.southafrica.info/doing_business/economy/. Accessed: 24/05/07 South Africa Info, 2007b. Skills Initiative to Boost Growth. http://www.southafrica.info/doing_business/economy/. Accessed: 24/05/07 Tshumisano. 2007. [Online]. Available at: http://www.tshumisano.co.za. Accessed: 28/03/07. Tshwane University of Technology (TUT), 2004a. [Online]. Available at: http://www.tut.ac.za. Accessed: 26/05/07 Tshwane University of Technology (TUT), 2004b. [Online]. Available at: http://www.fe.tut.ac.za. Accessed: 26/05/07 Wikipedia, 2007. Japanese Consumer Electronics Industry. [Online]. Available at: http://www.en.wikipedia.wiki/wiki/Japanese_consujmer_electronics_industry.html Accessed: 24/05/07 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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(ICERD 08013) Innovative Developments In Soil Dynamics Research Facility:

The FUTA Experience S. I. Manuwa; O.C. Ademosun; A. S. Ogunlowo; L. A. S. Agbetoye Department of Agricultural Engineering, The Federal University of Technology, PMB 704, AKURE E-mail: - [email protected] (corresponding author)

Summary The tremendous amount of earth moving, construction and land forming throughout the world has made machine handling of soil increasingly important in tillage, construction, military and mining operations.. This paper reports innovative developments in soil dynamics research facility in the department of Agricultural Engineering of The Federal University of Technology, Akure (FUTA), Nigeria. Professor Ademosun initiated the research in 1990. He developed soil tillage dynamics equipment that enabled model tillage tools to be evaluated for their performance in terms of draught and soil disturbance. The facility was later upgraded to be more versatile and to enable more studies to be carried out to investigate soil-tool interaction and draught requirements.

1. Introduction The tremendous amount of earth moving, construction and land forming throughout the world has made machine handling of soil increasingly important in tillage, construction, military and mining operations. Research in soil dynamics defines how traction devices and tillage tools operate in different soils, and soil conditions and soil-implement interaction. It also provides design criteria, which designers and manufacturers use to improve the efficiency of machines and implements. Until recent past, there were very scanty publications in this area of study in Nigeria simply because the facility were non-existent in our universities for such studies. Soil bin investigation of tillage tools is essential for the development and improvement in the performance of tillage implements. Soil bin systems enable tests to be performed under controlled or specific soil conditions (Kepner et al., 1978). In developed countries, soil bins with adequate instrumentation for force measurements have been developed. Such facilities include those at Silsoe College, Cranfield University, United Kingdom, and the National Tillage Machinery Laboratory, NTML at Auburn, USA [1].Professor Ademosun initiated soil tillage dynamics research in the Department in the late 1980s and since, efforts have been made to upgrade some items of equipment and develop other equipments that are necessary for in-depth laboratory studies in soil implement interaction. This paper therefore reports some innovative developments in soil dynamics research facility at the Department of Agricultural Engineering of The Federal University of Technology, Akure (FUTA), Nigeria. 2. Initial Developments of Soil Tillage Dynamics Equipments Soil tillage dynamics research started in the department with the development of soil tillage dynamics equipment consisting of a small wooden-box soil bin, a mini-track laying tractor (with hitch) and a power transmission system and a spring dynamometer for draught measurement. Features of the power transmission system include a 5 kW three-phase electric motor with driving pulley, an intermediate driven pulley, an intermediate driving pulley and a final driven pulley. Other components of the transmission system include, belts, wire rope and shafts. The facility enabled scaled models of tillage tools to be evaluated for performance in terms of draught and soil disturbance. The details of these

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yam equipments were reported in [2]. The equipment was also used to evaluate the performance of digging blades for coco harvesting [3]. The mini track-laying tractor was designed to ensure low sinkage, high bearing capacity and relatively high pull forces, for stability and good traction. The soil bin has a rectangular cross section. It was made of planks reinforced with angle-iron bars 15 m long, 1.5 m wide and 0.45 m high.

3. Features and Descriptions of Further Innovative Developments The need to upgrade earlier designs arose in the late 1990s when a Doctor of Philosophy (PhD) project was embarked upon in the department. During the course of the project, the following items of equipment were added to the list of the equipment: the dimensions of the soil bin was increased to 9.0 m long, o.85 m wide, and 0.45 m height; other facility include, a tool carriage and tool carriage sub frame, soil processing trolley, compaction roller and soil leveling board. Details of these equipments are described in [4] .By this upgrade of facility, soil bin investigations and soil-tool interactions were conducted using tillage tools (tines and blades) [5, 6, 7, 8]. Other items of equipment that have been developed to make the facility more versatile include a rotary tiller for soil preparation. Presently an overhead gantry is been developed for the soil bin to facilitate effective maneuverability of the machines in the preparation of soil for the different tests as are required. Some details of the facility are shown within the scope of length of the paper. Other items of equipment that have also been developed to make the facility more versatile include a rotary tiller for soil preparation and an overhead gantry to facilitate effective maneuverability of the machines. Sufficient details of the facility are shown within the scope of length of the paper.

Figure 1. An overview of the soil tillage dynamics equipment 1, load meter; 2, tool carriage; 3, tool vertical adjustment device; 4, tool angle measuring plate; 5, tool bar; 6,profilemeter; 7, soil processing trolley frame; 8, soil leveler; 9, compaction roller; 10, roller vertical adjustment device; 11 vertical adjustment pipe; 12, winding handle.

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A soil processing trolley with a compaction roller, a tool carriage, a power transmission system with a 3.1kW electric motor as prime mover, a tool mounting frame, a tool vertical and angle adjustment device, a profile meter for measuring soil disturbance parameters, and a spring dynamometer (load cell) for measuring draught. An overview of the soil tillage dynamic equipment is shown in Figure 1, with the full details presented in Manuwa (2002). The soil processing trolley with a compaction roller was used for leveling and compacting the soil to the required bulk density or penetration resistance (cone index) as desired for each test run The Dynamometer The Dynamometer or force-measuring device was a spring type. The capacity or maximum load achievable on it is 2kN with sensitivity of 10N (or 0.01KN). The dynamometer was calibrated for use using standard weights to give reliable data (Ademosun, 1990). In this study, the dynamometer was mounted on top of the tool carriage where it was connected by a steel rope through a sheave drive to the transmission system. The soil bin The soil bin is essentially a rectangular box of dimensions of length, width and height 9.0 x 0.85 x 0.5m respectively. The soil bin was made of four units each 2.25m in length. This was to facilitate transportation, maintenance and repairs as may be required through the dismantling process where necessary. The soil bin consists of the steel mainframe the wooden wall, and the steel rails. The steel rails (two in number) run parallel to each other along the whole length of the bin. They are made from steel angle sections 38 x 38 mm and supported by vertical posts. The width of the horizontal surface was compatible with the Teflon running wheels (of the trolleys) 30mm, thus with a clearance of about 8mm on the other side. The power Transmission system It consisted essentially of an electric motor, 5hp, pulleys (driving and driven), final drive pulley and wire rope. Variable speed was achieved by varying the size (diameter) of the pulleys appropriately as required. The speed is controlled by an electric switch, which puts the transmission system on and off as required. A wire rope was used to connect the transmission system to the tools carriage or soil processing trolley. Details of the design of the transmission system were reported in Ademosun (1990) The soil processing trolley It was designed for rigidity, stability, maneuverability, flexibility and maintainability; it was designed to run on four Teflon wheels. It was basically a four-wheel cart for transporting soil processing equipment along the bin. Its overall dimensions of length, width and height are 92 x 61 x 35.5 cm respectively. Also incorporated was provision for the vertical adjustment of the leveling board and also of the compaction roller. The trolley was suspended on two axles carrying Teflon wheels on bearing housing. The compaction Roller The soil compaction roller consisted mainly of a cylindrical drum, the roller axle and bearing and ballast weights, welded hitch and roller holding device, roller position adjustment device and the leveling board. The length and diameter of the roller were 50 and 42 cm respectively. The ballast weights were made of rods that were installed by bolting inside the roller cylinder had weight of 3.86 kg/m. The diameter of the rod was 2.5cm. The weight of the roller without the ballast weights was 15.9kg. The axle of the compaction roller was supported in two bearing housing, installed in Teflon wheels. Provision was made for the roller to be moved in the vertical or horizontal direction or be suspended in space through the position adjustment device and a welded hitch. The horizontal adjustment device consisted of two horizontal adjustment hitch plate. Each plate was made of a hollow 4.1cm square cross-section bar length 20cm welded to a rectangular plate. Two M12 bolts and nuts and a fixing plate 13 x 2.5 x 0.8 cm. The bolts were separated 8.2 cm centreto-centre. Raising or lowering the roller through the vertical adjustment pipe and fixing the position by means of a pin on each side of a horizontal adjustment plate accomplished the vertical adjustment The Leveling Board pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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It consisted essentially of a plane steel board, the vertical adjustment stud and the winding handle. The leveling board was reinforced for rigidity and had overall length, width and thickness of 80.0 x 30.0 x 0.02 cm respectively. The leveling board is used to level the soil before compaction

The tool carriage and tool carriage subframes These were also designed for rigidity, maneuverability, flexibility and maintainability. It as designed to run on Teflon wheels to minimize noise level arising from wheel to metal surface contact. The major components were the tool carriage mainframe and suspension ,the Teflon wheel and bearing housing, the variable –angle tool carriage subframe, fixing and vertical adjustment device for tools. The tool carriage mainframe was essentially an open-sided rectangular steel box. The length width and height of the frame were 92 x 50 x 30 cm respectively. It had provision for the attachment and vertical adjustment of tools by the holes drilled in the mainframe. The variable-angle tool carriage sub frame enabled the rake angle of the attached tool to be varied in a vertical plane through a pivoted angle measuring plate. Details of the description of the procedure are presented in Manuwa (2002). Major Parts of the rotary tiller: The rotary tiller consists essentially of the Carriage, the tool position adjustment device, the rotary blades, the transmission system, the speed reduction system and the power source. Details of the description of this equipment is presented in [9]

Figure 2: An overview of the rotary tiller

Conclusion An indoor soil bin facility for soil tillage dynamics research has been reported in this paper. The facility was the effort of years of research in this specialized area developed for the testing of model tillage tines and blades and for the evaluation of implement, soil and operational parameters of tillage. The facility will continue to enhance studies in the areas of precision farming, design and manufacturing of machines, and in pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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particular soil-engaging tools and implements, land application of bio-solids and compaction studies. It will also afford the University of extending knowledge to other establishments via training, workshops and extension services.

Acknowledgements The authors are grateful to the Federal University of Technology, Akure for the University Research Grant No. URG/MINOR/98/105 in supported part of this project. References [1]. Kepner, R.A., Bainer, R. and Barger, E.L. (1978). Principles of farm machinery, CBS [2] .Ademosun, O.C. (1990) The design and operation of a soil-tillage dynamics equipment. Journal of the Nigerian Engineer, 25(1): 51-57 [3]. Ademosun O.C. and Agbetoye, L.A.S. (1995): Performance evaluation of digging blades for harvesting cocoyam. Journal of the Institution of Engineers, India. Vol. 15, pp. 64 – 66. [4]. Manuwa, S.I. (2002). Development of an equipment for soil tillage dynamics and evaluation of tillage parameters. Unpubl. Ph.D. thesis, Federal Univ. of Tech., Akure, Ondo State, Nigeria. Pp 346. [5]. Manuwa, S. I. and Ademosun, O. C. (2004): Effect of Shape of Tillage Blades on Soil Disturbance and Draught. Nigerian Journal of Engineering Research and Development. Vol 3(4): 1-9 [6]. Manuwa, S. I. and Ogunlowo, A. S. (2005): The Influence of Speed and Rake Angle on Draught of Tillage Tools. Journal of Science and Technology Research, vol 4: 51-56. [7]. Manuwa, S. I. and Ademosun, O. C. (2007): Draught and Soil Disturbance of Model Tillage Tines Under Varying Soil Parameters. Agricultural Engineering International, the CIGR Ejournal, Vol. IX, March 2007, pp 1-18. [8]. Ademosun, O. C., Manuwa, S. I. and Ogunlowo, A. S. (2006): Development of an in door Soil Bin Facility for Soil Tillage Dynamics Research. FUTA Journal of Engineering and Engineering Technology Research. Vol. 5 (1): 31-36 [9]. Adewale, S. A. (2005). Development of a Rotary tiller for indoor Soil bin. A Postgraduate Diploma Thesis in the Department of Agricultural Engineering, The Federal University of Technology of Technology, Akure, Nigeria.

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(ICERD08015) LINKING UNIVERSITIES WITH INDUSTRY: A KEY ISSUE FOR SUSTANABLE DEVELOPMENT

Prof. Arezki BENFDILA, LMPDS, Faculty of Electrical Engineering & Computer Sciences The University M. Mammeri Tizi-Ouzou, Algeria. Regular Assoc. ICTP, Trieste Italy Email. [email protected], [email protected] The present communication deals with the stagnation of the university-industry cooperation and the ways to impulse the activity to boost the sustainable development. In developing countries, there is a gap between industry and universities and resulted in lower product quality and lack of research finances. Most of our universities are subsidised by the governments and the lack of finances had severe effects on teachers wages and, hence, on the teaching quality. In the same aspects, industry relies on importing prototypes sometimes not adequate for the local population culture and tradition and always with higher prices. This affected the selling volumes and hence the productivity and the employment generation. In this work, which try to evidence the main obstacles related to the weak interaction between industry and universities and the position of the governments in boosting the cooperation. We stress on the physicists bring about to convince industry to cooperate with universities and government to free universities and subsidise research and development in Industry.

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(ICERD08072) Effective Intra-Extra Campus Transportation System A. T Layeni, A. A Adeala Mechanical Engineering Department, Olabisi Onabanjo University, Ago-Iwoye, Ibogun Campus

The transportation system is an important factor in the development of any community. The means of moving human and goods to various places at a desired time is of paramount importance in the economic life of such communities. Transportation is therefore an important factor for growth and socio-economic development of any society. The educational institutions, particularly universities, are no exception being a community by itself and is expected that for students to perform optimally in their academics. The means of transportation to and fro hostel to lecture halls must be effective especially at institutions with no hostel accommodation on campus for students. This is a study into the effect of the present transportation system at the Olabisi Onabanjo University, College of Engineering & Technology, Ibogun Campus, on the activities of students and members of staff of the campus with a view to effecting changes if necessary to the present situation. The study was conducted to study the effect of the present transport system on the academic performance of students, especially attendance at classes, workshops, examinations and other academic activities. The present bus route and means of transportation was investigated. The effectiveness of the present means of transportation was analysed with a view of improving the present situation. This paper presents the findings of the research work carried out. Keywords Transportation System, Bus Route, Road Transport

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(ICERD08110) LEARNING AND TEACHING METHODS IN ENGINEERING EDUCATIONAL SYSTEM

1. EMAKPOR .S. 2. ENOMATE .J. 1 ELECT/ELECT DEPT, SCHOOL OF ENGINEERING, DELTA STATE POLYTECHNIC, OTEFEOGHARA, DELTA STATE, NIGERIA. 2. COMPUTER ENGINEERING DEPT, SCHOOL OF ENGINEERING, DELTA STATE POLYTECHNIC, OTEFE-OGHARA, DELTA STATE, NIGERIA.

This paper reports some excellent ways students can learn to avoid discouragement and poor performance in engineering education system. Over the years, there has been a problem between learning styles of engineering students and the traditional teaching method of engineering lecturers /instructors, and in consequence, students become bored and inattentive in classes, do poorly in tests, get discouraged about the courses, the curriculum, and themselves, and in some cases change to other curricula or dropout of school. On the other hand, lecturers confronted by low test grades, unresponsive or hostile classes, poor attendance and dropout, they now become overly critical of their students or begin to wonder if they are in the right profession Because of these problems we have lost some potentially, excellent engineers. This, notwithstanding, some excellent styles of teaching and learning of engineering education have been discussed in detail in this paper. However, which aspects of learning method are important in engineering education? Which learning methods are preferred by engineering students and which are favored by the teaching method of the lecturers/instructors? What can be done to reach students whose learning methods are not treated by standard method of engineering education? These questions are also addressed in this paper.

KEY WORDS: compatibility, style, active, reflective, hypothesis, intuitive, auditory, deductive, sequential Looking for last minute shopping deals? Find them fast with Yahoo! Search. Privacy Policy Terms Legal Site Map Advertise With Us Affiliates © 2007 SoftCom Technology Consulting Inc.

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(ICERD08136) Engineering Solutions for Rural Africa: A case study on the impact of engineering research on the socio-economic development of the rural Africa

Prof. Stephen Gaya Agong Engineering research must be tailored to resolving socio-economic problems without which no tangible development may be stimulated especially in the rural Africa. Developing engineering solutions that meet stakeholders' needs and expectations is the ultimate goal of any engineering research. This paper interphases the reality of the rural African needs and expectations and how the engineering can address some of these unique expectations.

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(ICERD08164) ADAPTIVE RESEARCH: AN APPROACH FOR FAST OPTIMAL RESPONSE FOR THE TRANSITION TO NEW TECHNOLOGIES IN THE SOUTH OF SAHARAN SUBREGION OF AFRICA 1

ADOKO SAMBWA Energy Consultant (Renewable Energy) 1 Asa-Lambda Technology Ltd. c/o Crossing Over Ventures, 9, Akpakpava Road, Benin City, NIGERIA. Email:[email protected] The past 100 years has been named the century with the rapidest economic and scientific development in human history, during which most part of the world has witnessed industrial production growth. The world has entered into a new development scenario in the 21st century. The industrial revolution, which is knowledge based factor, has elevated human society onto an unprecedented level, with tremendous capacity to master the nature. In the coming 50 to 100 years, we should be expecting another unprecedented scenario with the mastering of nanotechnology, renewable energy technologies, and many more. But on the contrarily, Africa South-Saharan Sub-region has equally proved what she is best of: Tribal wars, Hunger, HIV, Malaria, and acute poverty, to mention but a few. Faced with the ever growing technologies, it is a must for the south-Saharan scientists, engineers, and technologies to develop and adopt at this material time, a special methodology to encourage innovations. This, calls for the common efforts, cooperation among scientists, and ingenuity. The general view is that, with this trend of technological development, it is certain that the South-Saharan Africa will remain one of the largest importer and consumer of all sorts of technologies. Remarkably, the sub-region technological growth does not show any visible sign of abating. If truly the sub-regions quest to achieve the Millennium Development goals, the sub-region must consider her science, technology and research as prime movers where all sectors of growth must be fine-turned. Assessing the current state of the sub-region’s science and research activities, this paper draws on our experience to explore how better to develop a simple techniques to catch up with the development as being exhibited in the new technologies. This method will investigate different avenue of how to moderate growth through science and research, how to integrate the societal needs into research, how to ensure qualitative man-power, how to raise necessary fund for science and research activities, and finally, how to mitigate the effect of climate change. In this respect, the Adaptive research offers valuable lessons as how the subregion might proceed. But adopting the adaptive research as a method, is not just a question of technology, it requires policies to transform current practice. This paper will enumerate few such policy measures to stimulate basic science education that has been in practice for some years now, and possibly suggest new ways this could be strengthened to prevent total collapse of the sub-regions science and research. In the line of the above, the authors have considered as appropriate to illustrate some of their works as a proof to demonstrate the usefulness of the adaptive research. Keywords: Adaptive Research, Methodology, Suggestions, and Funding.

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(ICERD 08252) A BLIND SPOT IN STRUCTURAL ENGINEERING EDUCATION, WITH SPECIAL REFERENCE TO SLOPE-DEFLECTION METHODS OF STRUCTURAL ANALYSIS Engr. Adinna B.O1, Engr. Ezewamma. A. A.1, Engr. Nwaokike V. M.2, 1. Faculty of Engineering, Nnamdi Azikiwe University, Awka 2. Faculty of Engineering, Anambra State University, Uli ABSTRACT This paper provides a proof for slope-deflection equation from area-movement method of structural analysis (the most related topic) and recommends it as the first step in the teaching of slope-deflection to engineering students. Slope-deflection method of structural analysis is one of the most versatile methods of structural analysis which lends itself easily to matrix and computer application. In spite of these prestigious attributes, this method does not enjoy the deserved popularity among practicing engineers and undergraduates, who prefer other methods such as moment distribution, and Clapeyron’s three moment equation in their daily calculations. The reason for this is not far fetched. The teaching of this topic normally begins by quoting the slope-deflection equation, M = F.E.M + 2EI (2èA + èB - 3R), L without any formal proof. Both lecturers and authors of most textbooks are guilty of this act. This renders slope-definition method difficult to comprehend and retain. 1.0 INTRODUCTION 1.1 WHAT IS SLOPE-DEFLECTION METHOD? Slope-deflection method is a method used in analysing indeterminate structures, like continuous beams and indeterminate frames, which have members meeting at joints. Slope-deflection method takes its source from area-moment method of structural analysis. Area moment method, itself, is founded on the two theorems of Mohr. The two theorems of Mohr, respectively, state that the area of the moment diagram between two given points on a deflected shape of a structural member divided by the factor EI (stiffness modulus) gives the change in slope between the two given points; and the area moment of the portion of the moment diagram between the two given points about any vertical axis, cutting the axis of the structural member, divided by the factor EI, gives the intercept cut, on the given vertical axis, by the two tangents drawn, respectively, from the two given points. The case of a cantilever is demonstrated in fig 1.1. P A

B l

(i) A cantilevered beam with a point load at the cantilevered end.

x b

a

c d dx

e k

A è1 = 0 a R



e

è2

B C

R

(ii) Moment diagram of the cantilevered beam with the portion under consideration shaded. (iii) Intercept BC cut by tangents aB and eC

the

dè = 1 dx = M dx O J pdfMachine - is a pdf writer that produces quality PDF files with ease! Fig 1.1

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria R

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EI x2

è2 - è1 = ∆è = ∫

M dx … (1.1) EI = Area of trapezium (abce) EI Intercept BC = ∆è x x x1

x2

=x ∫

M dx … (1.2) EI = Area of trapezium (abce) x x EI x1

Where è and R are slope and radius of curvature, respectively, at the points in question, and x is the distance of the center of gravity of the shaded portion of the moment diagram from the vertical axis kJ. Equations (1.1) and (1.2) summarize Mohr’s theorems; and noting that the integral in equation (1.1) and 1.2 is equal to the area of the moment diagram between points x1 and x2 divided by EI, it is easy to see that the rotation at the tip of the cantilever is equal to the total area of the moment diagram divide by EI (area of ∆abcd/ EI), while the deflection at the tip of the cantilever is equal to the area of the moment diagram multiplied by the distance between the centroid of the moment diagram and the vertical axis passing through the tip of he cantilever, divided by EI(area of ∆abcd x x / EI) These two simple facts (Mohr’s theorems) embodied in equations (1.1) and (1.2) are developed into what is called the conjugate beam method, whereby the bending moment diagram of a beam is superimposed on the beam as load, and the moment and shear force obtained at any section on the beam ,divided by EI, give the deflection and slope ,respectively, at the point in question. Below is an illustration for a simple supported beam with a central point load (fig 1.2) P kN

(i) simply supported beam with a central point load.

l P kN

(ii) Moment diagram of the beam, with the reactions at the supports. P

/2 KN

P

Pl

/4 KNm

a

/2 KN

Pl

/4 KNm

a

è1 Pl

2

è2 Pl

/16 KNm2

2

/16 KNm2

M'(kNm2) x Pl

Q'(kNm2)

2

/16 KNm2

Section a -a' Fig 1.2

(iii) The moment diagram superimposed on the beam as load, with the resulting ‘secondary’ reactions, which give the slopes è1 and è2 ,in radians, when divided by EI. (iv) A portion of the superimposed moment diagram over the length x of the beam with the exposed ‘secondary’ shear and moment (sec. a-a'), which give the slope and deflection, respectively, at that section when divided by EI.

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Slope-deflection method evolves from the explanations in Sec 1.1. It begins with a simple intuition that for an indeterminate structure, like continuous beams and frames, the final end moments at the joints, for each of the structural members, is the sum of the fixed- end moments, if the joints are assumed ‘locked’ so that there is no rotation, and the moment contributed by the rotation of the joints, when the locking mechanism is removed; and also the moment contributed by the displacement of the joints, if there is any. Below is an illustration for the case of a continuous beam (fig 1.3) q

q

P

A

B

C èC

D

(i) Loading diagram for a 3-span continuous beam

D

(ii) Rotation diagram for the continuous beam

èD

èA èB B

A

C

(iii) Fixed -end moment diagram for each member with the supports assumed locked or fixed.

Support fixed

Fig 1.3

To determine the value of moments contributed by each case – fixed ends, rotations and vertical displacements- the following idealizations for each member of the structure is used in the theory of slopedeflection: F.E.MB F.E.MA

q

(a) A

B

Fixed ended beam which gives the fixed-end moments when the supports are locked.

B

Propped cantilever with a moment MB applied at the propped end B

L MA (b)

MB èb

A MA = 2EI èB L

MB= 2EI èA L

MA

èb

MB B

(c)

Propped cantilever with a moment MA applied at the propped end A.

MB= 4EI èA L

MA = 4EI èB L

MB B MA (d)

A

d R MA = 6EI èB L2

MA (e) A

MB= 6EI èA L2 MB B d

R

Fixed ended beam with supports moved to different levels without rotation of the supports

Alternative to Fig 1.4.d when one of the supports is on rollers or pinned.

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The final end moment at the ends of each member in the structure can be obtained by the addition of the moments at the corresponding ends of the idealizations (a) – (e) in fig 1.4, taking anti-clockwise moment as positive. This gives the following results. MFA = F.E. MA + 2EI (2èA + èB – 3R) L MFA = F.E. MA + 2EI (2èA + èB – 3R) L

…(1.3) …(1.4)

Where MFA is the final moment at support- end A, F.E.MA is the fixed- end moment at support-end A, èA is the rotation, in radians, at support-end A, èB is the rotation, in radians, at support-end B, R is the vertical displacement d of one of the supports divided by L (unit in radians). R = d/L Equations 1.3 and 1.4 are both called the slope- deflection equation. The factor 1.5R is used when one of the extreme supports is on rollers or pinned. The idealized beams with the end moments expressed in terms of rotation angles, èA and èB, are presented just as above(fig 1.4),without providing any formal proof for these moment equations, in virtually all textbooks. This presents serious problems to engineering students, as they just have to cram without knowing how it comes about. This constitutes the ‘blind spot’. These formulas are proved in the next section. 2.0 METHODOLOGY 2.1 PROOF To prove that the formulas for the end moments MA and MB of the idealized beams (fig 1.4) are as follows:F.E.MA

(i) Propped cantilever with moment applied at the propped end B (fig 1.4 b): MA = 2EIèA, MB = 4EIèA L L

*(a)

q

A

B

L MA

(ii) Fixed ended beam with supports at different levels without rotation of the supports about its horizontal axis (fig1.4d): MA = MB = 6EId L2

(b)

MB èb

A MA = 2EI èB L

MB= 2EI èA L

MA

MB B

(c)

MB= 4EI èA L

at

MB B MA (d)

* Fixed end moments (fig 1.4a) are excluded in the proof because their formulas and proofs are available in most textbooks.

B

èb MA = 4EI èB L

(iii) Propped cantilever with supports different levels (fig.1.4e): MA = 0, MB = 3EId L2

F.E.MB

d R

A

MB= 6EI èA L2 MB B

MA = 6EI èB L2 MA

d R

(e) A MA = 0

MB= 6EI d L2 Fig 1.4 Repeated

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2.2 PROVE: (i) Propped Cantilever: Consider a propped cantilevered beam shown below (fig 1.5a) with an applied moment MB, MB B

A

RB

MB

MB

l

(c)

(a) MB 2

RBL (b)

RB

MB

(d) Fig 1.5

Deflection at support B is zero (fig 1.5a), therefore the net deflection at B due to the reaction RB and the applied moment MB is zero, i.e. sum of the moment of the moment diagrams in fig 1.5b and c about support B is zero. Thus -RBL L 2L + MB L L = 0 EI 2 3 EI 2 3 2 -R L + M L = 0 B B ∴ 3 2 RB = 3MB …(2.1) 2L

Substituting this value of RB in equation (2.1) for the reaction of the beam in fig 1.5a, and taking static moments of all the forces about support A, we have -3MBL + MA + MB = 0 2L MA = 3MBL - MB 2L = MB …(2.2) 2

MB A

B MB 2L

The resulting bending moment diagram of the propped cantilever will be as shown in fig 1.5 d. Superimposing the moment diagram in fig 1.5d on the propped cantilever as load (fig 1.6 ) and summing moment of the secondary load and secondary reaction at B about A give the secondary reaction R'B, which when divided by EI gives the slope at B (we take moment at A because deflection at A is zero). Thus R'BL - 2L MB 2 2L + L + 1 MB L 1 L = 0 3 2 3 3 3 2 2 3 3 3 R'BL = MBL2 - MBL2 27 108 R'B = MBL 4 èB = MBL 4EI MB = 4EIèB and MA = 2EIèB …(2.3) L L

B L

2L

/3

/3

R'B

Fig 1.6

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(ii) Fixed ended beam with supports at different levels: Consider a fixed ended beam (fig 1.7) with the supports at levels separated by a distance d, without the supports being rotated about their horizontal axis. MB

MB A

MA

B

d MA

A

l

l

/2

l (i)

Fig 1.7

/2

(ii)

The bending moment diagram is as shown in fig 1.7(ii), with MA = MB. Considering this moment diagram as load on the fixed ended beam (moment diagram below the beam is considered positive load, while portion of the diagram on top of the beam is considered as negative load, pointing upward) and taking moment of the secondary load at B, and dividing the result by EI, the displacement d is obtained. Thus: MA L 5L - MB L L 2 2 6 2 2 6

= d

Since MA = MB, we can write M L 5L - M L L 2 2 6 2 2 6

= d

5ML2 - ML2 = d 24 24 d = ML2 6EI ∴ MA = MB

= 6EId L2

…(2.4)

(iii) Propped Cantilever with supports at different levels: Consider a propped cantilever (fig 1.8) with supports at levels separated by a distance d; and the moment diagram as shown below. MB B A

MB

d

R

B l

l

(i)

(ii)

Considering the moment diagram (fig 1.8 ii) as load, and taking moment of the secondary load at support A and dividing the result by EI, gives the distance d; thus MBL 2L = d 2 3 d = MBL2 3EI MB = 3EId L2

…(2.5)

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Drawing these moment values obtained from steps (i) to (iii) on the idealized beam as shown in fig 1.4, and summing up the moments at corresponding supports, considering clockwise moments as positive, gives the slope deflection equation: MAF = F.E.MA + 2EI (2èA + èB + 3R ) L MAF = F.E.MA + 2EI (2èA + èB + 3R ) L

1.3 Repeated 1.4

3.0 CONCLUSION For proper teaching and understanding of slope deflection method, the following suggestions can be followed. (i) (ii)

Area – moment methods should be taught ahead of slope-deflection methods Proof outlined in section 2.2 of this paper, or a similar proof, should be a first step in the teaching of slope deflection.

REFERENCES R.S KHURMI (2005) “Strength of Materials” S. Chand and Company Ltd, Ram. Nagar, New Delhi. C.S. REDDY (2004) “Basic Structural Analysis” Second Edition, Tata McGraw- Hill publishing company ltd, New Delhi. G. H. RYDER (2003) “Strength of Materials,” Third edition, Rajiv Beri for Macmillian India Ltd, New Delhi.

CONSTUCTIONAL STEEL RESEARCH AND DEVELOPMENT ORGANIZATION(1983) “Steel Designers’ Manual” Fourth Edition, (Revised), Granada publishing ltd, Great Britian. Prof. A DARKOV (1989), “Structural Mechanics” Mir publishers ltd, Moscow

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(ICERD08267) COMPARATIVE ANALYSIS OF MANUFACTURING STRATEGY OF

INDUSTRIALIZING ECONOMIES AND NIGERIA

E. O. Ezugwu and I. O. Abdulmalik Machining Research Centre, Faculty of Engineering, Science and the Built Environment, London South Bank University, 103 Borough Road, SE1 0AA, United Kingdom Available literature on manufacturing strategy have structured the content of the process into five areas: Corporate needs, the market strategy, order winning criteria, process and infrastructure. This paper reviews the strategic manufacturing approach of some industrializing nations in comparison with Nigeria in the context of automotive development for wealth creation. Recent investigation of developments in the automotive sector in industrializing economies attempt to redefine the understanding of the concept of ‘made – in – Nigeria’ vehicle and the realization measures. It also highlighted factors that ensure the sustainable growth of the automotive sector in the industrializing economies such as government golden shares, relevant legislations, patronage as well as issues relating to quality, cost and delivery of automotive products and components. This paper will finally propose some remedial modules of realignment of Nigeria’s automotive sector in order to be sustainable and competitive in the global market, such as creating stakeholders’ network for the National Automotive Council (Net4NAC); proposed interactive innovation of Nigeria’s automotive sector through radical change in business culture, restructuring, recapitalization, technology transfer possibilities and capacity building; realignment of technology and user environment through mutual adaptation of sustainable manufacturing model with special reference to adaptation cycle in detrimental and beneficial issues.

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TECHNICAL SESSION 1B:RENEWABLE ENERGY I

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(ICERD 08005) SMART CONDITIONING OF THE OUPUT CHARACTERISTICS OF A

PHOTOVOLTAIC POSITION SENSOR USING A FEEDFORWARD NEURAL NETWORK SYSTEM J. T. Agee1, T. T. Tumane, M. Shedden and M. Jeffrey Department of Electrical Engineering, University of Botswana. P. Bag 0061, Gaborone. BOTSWANA E-mail: [email protected] EXTENDED ABSTRACT Introduction: The significance of solar energy in the energy-mix of many countries has been increasing. Correspondingly, interest in the development of efficient devices for harvesting solar power has also increased. Tracking solar power devices particularly have gained appeal in many such projects. Most tracking solar power devices use a combination of photo-sensitive devices to generate an error signal which is then used to control the solar equipment in a manner that enables the tracking of sunlight. In our work, reported here, the photo-sensor used consists of two photovoltaic cells. The characteristics of this sensor are shown in this paper to be nonlinear. The paper further presents a feed-forward neural networks that smartly linearises the output characteristics of the sensor. A photovoltaic cell is a two terminal device which consists of a photodiode. Light falling on the diode causes a current across the device. The photo-current IPH, of the photovoltaic cell, due to incident light of intensity IR is given by: IPH = K1AIR

1

where: K1 is the sensitivity of the sensor and A is the total surface area of the photocell exposed to the incident radiation. The incident light also causes a voltage VC  VO log(1  I R ) 2 where: VC = open-circuit cell voltage; Vo = constant, dependent on cell material; I R = light intensity Thus, the photovoltaic cell could be considered a light dependent voltage source, whose internal resistance Rc and short-circuit current ISC are related by:

I SC =

VC

3

RC

Current modeling in a photovoltaic cell: since the model representation of the photovoltaic cell consists of a diode, external current obtainable from the cell is the difference between the photo-induced current IPH and the equivalent diode current, as shown in equation (3).  V I  I PH  I D  I PH  I S  (exp C  m  VT

   1) 

4

where: IPH: Photo current; ID: Diode current; IS: Diode reverse saturation current; m: Diode “ideally factor” m= 1VT -5VT; The thermal voltage: VT 

k T ,VT = 25,7mV at 25°C; k:constant of Boltzmann k = e

1,380658 · 10-23 JK-1 ; T: absolute temperature; [T] = K (Kelvin) 0 K = -273, 15°C; e: charge of an electron e = 1,60217733 · 10-19 As For real solar cells, a voltage drop across the internal resistor Rc could also be observed. Furthermore, there is the sinking of some current IP through an apparent resistor RP. Hence:

I  I PH  I D  I P = I PH  I S (e

VO log(1 I R ) mVT

 1) 

VO log(1  I R ) RP

5

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It is obvious from both equations (4) and (5) that, the external current delivered by a photocell is nonlinearly related to the light intensity IR. Two Photovoltaic cells were required to measure the position of a solar power platform, relative to the axis of sunlight. A photocell each was installed on either side of a line running perpendicular to the direction of rotation of the platform. Let these cells be “a” and “b” respectively. By equation (1), each cell generates a current, Ia and Ib, respectively, proportional to the intensity of its incident radiation. The difference between Ia and Ib is conditioned to generate an error voltage which is then used to control the motion of the platform, as explained in the next paragraph. Suppose that each of the two photovoltaic cells have a surface area A m2. Then, in the case where the platform is aligned with the direction of the sunrays, each cell produces the same amount of photo current IPH=I0. The difference between the current from the two cells is zero Ampres, there is no resultant control signal and the platform remains at its current position. Now, suppose that the direction of sunlight momentarily changes, so that the platform is misaligned by and angle  degrees to the direction of sunrays. It is shown in reference [7] that I a  I 0  K 1 tan   I S (e

I b  I 0  K1 tan   I S (e

VO log(1 I R ) mVT

VO log(1 I R ) mVT

 1) 

VO log(1  I R ) RP

6

 1) 

VO log(1  I R ) RP

7

Note that, measurements of the currents in equations(6) and (7) contains information on the misalignment  , however, the manipulation of these currents to produce  results in nonlinearity, as shown in Figure 1. We show in the paper, how a feed forward neural network could be trained to extract linear voltages proportional to the angle of misalignment, using a feedforward neural network with Ia and Ib as its inputs. Sample results are shown in Figure 2. Angle against Ia-Ib 15

Network output against Angle 21.7

10

21.6

21.5

Output

Ia-Ib

5

0

21.4

21.3

-5 21.2

-10 21.1

-15 -80

-60

-40

-20

0 Alpha

20

40

60

80

21 -80

Figure 1: Nonlinear Ia-Ib versus á characteristics

-60

-40

-20

0 Alpha

20

40

60

80

Fig 2: Linear Ia-Ib characteristics from

neural network processing Conclusion Smart linearization of the nonlinear characteristics of the photovoltaic position sensor is achieved using a three layer feed-forward neural network with four neurons in the hidden layer and one neuron in the output layer. 8. Reference [1]. Curtis D. Johnson, Process Control Instrumentation Technology, Seventh Edition. [2]. www.sunceramcat.pdf [3]. www.emsolar.ee.tu-berlin.de. [4]. Jenny Nelson, The Physics of solar cells. [5]. Archer Hill, Clean Electricity from Photovoltaics. [6]. John P. Bentley, Principles of Measurement Systems, Fourth Edition. [7]. Kuo. C. Benjamin, Automatic Control Systems. [8]. MATLAB notes. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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(ICERD 08006) Improving the efficiency of solar cells using quantum dots S.Y Mensah,1 N.G. Mensah,1 J.A. Yankey,1 and F.K.A. Allotey.2 1 University of Cape Coast, Cape Coast. 2 Institute of Mathematical Sciences, Accra. abstract: Even though solar energy is free, clean and inexhaustible, harvesting solar photons, for the efficient production of electrical energy has been a scientific nightmare. This is due to the one-photon-one-exciton rule that has characterized the interaction between solar photons and bulk semiconductor solar cells. Subsequently, the efficiency of conventional solar cells has been between 20 and 30% to date. However, the inclusion of quantum dots in solar cells promises to increase their performance under standard illumination. Recent research indicates that quantum dots produce multiple excitons through impact ionization. The leap in the number of excitons implies that the efficiency of solar cells could be increased up to between 42 and 60%. In this thesis, I intend to highlight the current research in this area and suggest the way forward. Introduction Amidst concerns that the world’s fossil fuel reserves are finite and depleting [1], much interest has been devoted to finding energy alternatives. Among the contenders competing to replace fossil fuels, direct conversion of sunlight to electrical energy using photovoltaic solar cells is one of the important alternatives and a challenge that mankind faces today. Photovoltaic solar cells offer many advantages including being low in maintenance and relatively environmentally friendly and have a large number of applications in addition to the potential for many more, particularly in the energy, communications, military and space industries. Even though solar radiation is free, plentiful and a clean source of power and also the technology for its conversion into useful energy has been around for over five decades, the major draw back to the wide spread use of conventional silicon photovoltaic solar cells to date has been its prohibitive cost and low device efficiency. The efficiency of conventional solar cells is small because of their inability to absorb all of the incident solar energy and secondly their inability to convert all of the photons energy that is absorbed to free electrons and holes in the material component. The maximum power conversion efficiency obtainable with conventional single junction solar cell is given by the Shockley and Queisser limit. Using detailed balance approach, and assuming that each photon above the material bandgap produces just one electron-hole pair while all photons with energies below the bandgap are lost, one obtains a theoretical maximum energy conversion efficiency of 30% [2]. This is unsatisfactorily low mainly due to thermalisation and transmission losses which together accounts for about 56% loss in photon energy. However

to consider the Shockley and Queisser limit as the ultimate limit achievable with photovoltaic cells is woefully incorrect and that the actual limit could be much higher. If the sun being the solar cell energy source, emitting at a temperature of 5760K and a solar cell at 300K are considered as black bodies, the Carnot thermodynamic efficiency is 95%. Calculations by Lansberg and Baruch [3] give an efficiency of 93.3% in which radiative losses from the solar cell was considered. Taking into accounts entropy generation during energy conversion, one obtains a black body limit of about 86%. The large difference between the Shockley-Queisser and the thermodynamic limits is due to a mismatch between a single material which is characterized by only two energy levels and the solar spectrum which contains a wide range of energies. From the foregoing, devices that rely on a single transition between energy levels are intrinsically not suitable for the broad solar spectrum. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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In essence, large area, durable solar cells are required with inexpensive manufacturing, inexpensive starting materials and a reasonable efficiency. Unfortunately, contemporary photo voltaic solar cells fail on all counts Notwithstanding, there is a potentially huge market for solar cell utilization if their cost were to approach or decrease past the cost of combusting fossil fuels.

Several schemes have been proposed over the past five decades to produce better solar cells well suited to the broad solar spectrum [4]. This review, specifically demonstrates the theoretical basis for overcoming the Shockley and Queisser limit by the inclusion of quantum dot in solar cells through Multiple electron generation (MEG) solar cell concepts. Basic structure of solar cells Solar cells are devices that convert light energy to electrical energy. An essential component of all photovoltaic devices are two separate layers of semiconductor materials, one with an abundance of electrons ,n-type that functions as the “negative pole” and the other with an abundance of holes, p-type (vacant positively charged energy spaces) that functions as a “positive pole”. They can be made from a wide range of semiconductor materials which could be the elements in groups IIIV, III-V or IV-VI on the periodic table. These materials may be deposited or arranged in various structures for optimum performance. The three main types of materials used for solar cells are 1.Silicon (Si) which can be used in various forms including a) Single crystalline b) Multicystalline and c) Amorphous 2.Poly-crystalline thin films such as copper indium diselenide (CIS), Cadmium telluride (CdTe) and thin film Silicon. 3.Single-crystalline thin films- including high efficiency materials such as gallium arsenide (GaAs). Figure 1 is the design of a solar cell showing its essential features.

Figure 1. Structure of conventional solar cell [5]. It consists of a glass or plastic cover or other encapsulant, an antireflective layer, a front contact to allow electrons to enter a circuit, a back contact to allow them to complete the circuit, and a semiconductor layer where the electrons begin and complete their journey. Solar radiation The major source of energy to operate a solar cell is the sun which radiates energy from gamma rays down to radio waves. Most of the energy is released as visible light even though visible light represent only a small fraction of the total solar spectrum. The radiation from the sun consists of discrete packets of energy called photons that range in frequencies. Illustrated in Fig 2 is the spectrum of solar radiation. In terms of wavelength, the sun emits almost all of its energy in the range 2  10 7 to 2  10 6 m . Each wavelength corresponds to a particular frequency and pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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energy E   where is  Planck’s constant and  is the frequency of radiation. The shorter the wavelength, the higher the frequency and the greater the energy. Red and violet lights are at the low and high energy ends of the visible spectrum respectively with violet light having twice as much energy.

Figure 2. Representation of the solar radiation specifically indicating the visible spectrum necessary for the action of a solar cell [5]. The sun may be considered as a black body at a temperature of nearly Tsun = 5767K radiating electromagnetic spectrum in the solar system. Using a dilution factor

f  (

Rsun 2  sun )  where Rsun and RSE are the radii of the sun and earth RSE 

respectively.  sun is the solid angle subtended at the earth, we obtain the solar constant 4 S  fTsun  1.367kW / m 2 which is the average extraterrestrial irradiance, i.e. the radiation intensity that

reaches the outer edge of the atmosphere. The atmosphere reflects and absorbs some of this radiation including most x-rays and ultraviolet rays. Again, much of this energy is lost in traveling from the edge of the atmosphere to the surface of the earth which depends on the thickness of the atmosphere the energy must passes through. Assuming a fraction 0.7 reaches the earth’s surface when the sun is directly over head in clear sky, then the terrestrial irradiance is SE = 0.7S = 957W/m2 ~ 1000W/m2 denoted by AM1.5G which is chosen as the standard value of radiant power. As the sun moves lower in the sky, the energy passes through a longer path of air, loosing more energy and thus reaches a value less than 1000W/m2. This radiation is distributed unevenly in different regions on the earth with the regions near the equator receiving more solar radiation than anywhere else. The number 1.5 indicates that the length of the path through the atmosphere is 1.5 times, the shorter path when, the sun is directly over-head. The standard spectrum outside the earth’s atmosphere is AM0 which is useful for predicting the performance of a solar cell in space. The mean daily irradiance is obtained with the use of a geometrical factor of 14 which takes accounts of the angle between the sun rays and a plane parallel to the earth surface often called the peak solar hours (PSH) = GE = 14 x 24h = 5.75kW/h. This figure is needed in the sizing of the stand alone PV system. In practice one uses the mean solar radiation near the site of installation and its variation throughout the year rather than the average yearly radiation which is 14 SE = 238W/m2 The amount of the sun’s energy that reaches the surface of the earth every hour is greater than the world’s population energy needs in one year hence the sun represents an abundant source of renewable energy to humanity [6]. Interaction of photons with bulk semiconductor material As illustrated in Fig 3, a stimulus such as heat, voltage or photon flux can cause an electron to jump from the highest level of the valence band to the lowest edge of the conduction band leaving a positively pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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charged hole in the valence band. The electron in the conduction band edge and the hole in the valence band form a bound system like a hydrogen atom called an exciton.

For each material, there is a fixed physical average separation between the electron and the hole called the Bohr exciton radius (BER). The characteristic distance between these two charges is

2 e2

 1 1   *  *  (1)  me m h  * * where me and mh are the effective mass of the electron and hole respectively, e is the elementary charge and  represent the dielectric constant of the bulk semiconductor a Bex 

[7-9]. In bulk semiconductors, the crystals are much larger than the BER, the exciton stretches to its full extent leading to continuous energy levels both in the valence and conduction bands, meaning there is almost no energy difference between them. Although many solar photons carry enough energy to theoretically create several electrons or excitons, they hardly free more than one electron. This is because the photo-generated electron often collides with nearby atoms of the bulk material and is less likely to set other electron free to generate other excitons. Rather due to the continuum of states, there is a rapid sequential emission of phonon quanta, a process which is quantum mechanically feasible because it requires the loss of less energy.

Figure 3 Bandgap of bulk semiconductor showing the exciton levels [10] Thus the exciton excess bandgap energy is squandered as heat (Thermalisation loss). This may lead to a fast relaxation of the exciton to their lowest energy levels and their subsequent recombination, cooling the carriers and heating the lattice until their temperature is the same. In bulk semiconductors, the distribution of the excess exciton kinetic energy between electrons and holes is determined by their effective masses. The carrier having lower effective mass receives more of the excess energy [9] hence

Ee  (h  E g ) 1  me* mh*



1



(2)

Eh  (h  Eg )  Ee

(3) where Ee is the difference in energy between the conduction and the initial energy of the photo-generated electron and Eh is the energy difference between the valence band and the photo-generated hole. The illustration is in fig 4. The action of the built-in-voltage at the p-n junction in conventional bulk semiconductor solar cells is a fast collection of the electrons and holes away into the external circuit to constitute a photogenerated current and a photovoltage [11] before the hot exciton relapse to their lowest levels. This accounts for the one-photon-one electron rule characteristic of bulk semiconductor solar cells. The solution pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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to this are alternative solar cell concepts that harvest the excess band gap energy of photons to produce photocurrents and photovoltages normally referred to as third generation solar cells. Among the several schemes are the following 1 Hot carrier solar cells [13-15] 2 Solar cells producing multiple electron-hole pairs per photon (impact-ionization) [16-20]

Figure 4 Hot carrier relaxation / cooling in a semiconductor solar cell [12] 3 Thermo-photonic cells [17] 4 Multiband and impurity solar cells [18-21]

Impact-ionization in quantum dots Quantum dots are zero dimensional nanometer-sized artificial systems where a few or up to several thousand electrons are confined in all three spatial directions, in a region of the order of the electron deBroglie wavelength and as a result lead to discrete or quantized energy levels or display a delta function density of states similar to real or naturally occurring atoms [22]. This is because the smallness of the size makes the electron de-Broglie wavelength begin to “feel” the boundaries of the dot as one or more of the dimensions of the dot approach the Bohr exciton radius. The quantum confinement effect means that the electron angular momentum, the hole and electron energy levels become discrete, in other words there is a small but finite separation between the energy levels of the quantum dot [23]. Under these conditions, the particle ceases to resemble bulk semiconductor material. Interaction of radiation of sufficient energy with a quantum dot also produces excitons in the dot. Fig 5 illustrates the excitonic states in a quantum dot. The lowest electron state is labeled 1Se while the lowest hole state is labeled 1S3/2. Based on the effective mass approximation, Brus [7] showed for quantum dots that the energy gap between the lowest level of the conduction band (Lowest Unoccupied Molecular Orbital (LUMO) and the highest level of the valence band (highest occupied Molecular Orbital (HOMO) can be approximately calculated by

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Figure 5 Left: discrete energy levels of a CdS quantum dot. Right: excitation of the quantum dot with 3.15eV photon generates a distribution of hot electron and hole states. Cooling (dashed arrows) eventually results in electrons and holes decaying to their lowest energy 1S3/2, and 1Se states respectively.

E 

 2 2 2R 2

 1 1  1.8e 2    * * R  me m h 

(4)

where R is the radius of the quantum dot. In equation (4), the first term relates to the quantum localization which shifts the energy gap to higher energies as R-2. The second term is the coulomb term which shifts the energy to lower energies as R-1. Consequently, the total energy gap increases in energy when decreasing the quantum dot diameter [7]. By altering the boundaries of the band gaps, the energy levels of the valence and conduction bands of the quantum dot can be adjusted. This may be done by either subtracting or adding atoms to the dot or changing the shape (geometry) of the dot. Since the emission frequencies are dependent on the band gaps, the wavelengths can be controlled. The band gap of a quantum dot can therefore be precisely tuned to emit different wavelengths [24, 25]. Thermodynamic calculation of the conversion efficiency of MEG solar cells This section considers the calculation of the conversion efficiency limit of a single junction solar device which employs quantum dot absorbers based on the principle of impact-ionization discussed by Hana and Nozik [26]. In this calculation, the basic assumpti- ons are; All photons with energy above the absorption threshold are absorbed The quasi-Fermi level separation is constant and equal to qV across the device which is equivalent to the assumption of infinite carrier mobility and finally the only active recombination mechanism is radiative recombination. The current-voltage relationship for a single junction device is given by I (V , E g )  I G ( E g )  I R (V , E g ) (5) where I G is the photo generated current, I R is the recombination current associated with radiative recombination Eg is the absorption threshold or band gap of the barrier and V is the photovoltage generated by the cell. The photo generated current I G and recombinationcurrent I R are obtained from E max

I G (V , Eg )  q

 QY ( E )( E )dE

(6)

Eg

QY(E)E2 I R (V , Eg )  qg  dE Exp{[E  qQY(E)V ] / kT}  1 Eg 

(7)

where E is the photon energy, Q is the electron charge, K is the Boltzmann’s constant, T is the temperature of the solar device (T=300K) g  2 c 2 h 3 , where c is the speed of light in vacuum and h is Planck’s constant. The quantum yield QY (E) allows for the generation and recombination of multiple charge pairs per photon over the appropriate energy range. The unconcentrated ASTMG-173-3 solar spectrum [27] is used as the illumination source. (E ) is the photon flux associated with the AM1.5G spectrum. Emax is the maximum photon energy in the solar spectrum; For AM1.5G, Emax = 4.428eV approximated to Emax = 4eV for practical purposes, the resultant integrated solar current above 4eV in the standard AM1.5G spectrum is ~ 5Acm 2 . In (7), carrier generation from ambient black body radiation is neglected which is a reasonable approximation for Eg = 0.2eV. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Multiple exciton generation is implicit in the analysis through the energy dependent quantum yield QY(E) which may exceed one over certain photon energy ranges. For an ideal MEG quantum dot absorber, the form of QY(E) is given by a sum of the step function M

QY ( E )   ( E , mEg )

(8)

m 1

Where  ( E , mEg ) is the Heavisde unit step function. M=1, gives the usual one-photon, one-electron-hole pair.

M  M max  E max E g gives the maximum number of excitons and the highest possible efficiency for an MEG device. MEG absorbers may be denoted by M = 1, M = 2 and M = Mmax respectively by M1, M2 and Mmax. The conversion efficiency of a photovoltaic device at a given point is  pv (V )  I (V )V / Pin (9) where Pin = 100mW/cm2 is the integrated optical power in the AM1.5G spectrum. The value of the voltage V in (9) is obtained by the following consideration of actual water splitting devices. The photochemical conversion efficiency for the production of stored chemical energy as H2 from water splitting is given as  H 2 (V )  I (V )U H 2 / Pin (10) where U H 2  1.23V is the minimum thermodynamic potential required for water splitting at 300K. The operating voltage or bias point of the cell will be larger than U H 2 by the sum of the anode and cathode over potential (loss) and the resistive potential drop of the electrolyte. Denoting the sum of these over potentials (loss) by Vover and assuming it is independent of the current, then the operating voltage

V  Vover  U H 2

(11)

By maximizing the efficiencies of (10) and (11), the maximum efficiency of a single junction photovoltaic device with a given threshold Eg and quantum yield QY(E) can be obtained from (5) to (9). Several authors [28-33] have subsequently reported values of the efficiency of single junction solar cell devices which rely on carrier multiplication by impact-ionization exceeding the Shockley and Queisser limit. Under standard AM1.5G illumination, the maximum efficiency for single junction solar cells operating at 300K with quantum yield determined from (5) to (11) is shown in fig 6 The curve M1 is without carrier multiplication and corresponds to the usual one-photon-one-exciton rule i.e. the Shockley and Queisser limit with maximum efficiency 33.7%, occurring at Eg = 1.3 eV. From the graph, an efficiency value of 42% is obtained with carrier multiplication of M = 2 i.e. curve M2 which is 94% of the absolute maximum. The implication is that higher multiplication values >2 are not a pre-requisite for substantially increasing the efficiency of a single junction solar device based on impact-ionization. Conclusion The preceding review has shown that through MEG, the power conversion efficiency of quantum dot-based solar cells can be improved to a value of 42%, which is less than the thermodynamic limit but much higher than the Shockley and Queisser detailed balance limit.

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Figure 6. PV conversion efficiency as a function of quantum dot bandgap for single junction devices with the following absorber types; M1 (no exciton multiplication), M2 (two excitons per photon above hv = 2Eg) and Mmax (maximum possible number of excitons per photons from solar spectrum) The curve Mmax is obtained by using the maximum integral number of carrier multiplication possible with the available excess energy Mmax = Emax/ Eg. This corresponds to a maximum efficiency of 44.4% for a single junction with bandgap Eg = 0.7 eV where Emax = 6. References [1]M. King Hubbert, world’s evolving energy systems, Am. J Phys.49 (11), 1007-1029 (1982). [2] W. Shockley, H. J. Queisser, Detailed balance limit of efficiency of p-n junction solar cells. J. Apply. Phys. 32:10-519 (1961). [3] P. T. Landsberg, P. Baruch, 1989. J. Phys. A. 22, 1911. [4] M.A. Green, Third generation photovoltaics; Advanced Solar Energy conversion (Springer Berlin) (2003). [5] http://www1.eere.energy.gov/solar/solar cell structures.html [6] R. M. Nault, In: Basic research needs for solar energy utilization. Report on the basic energy source workshop on solar energy utilization. Argonne National Laboratory U.S.A.(2005). [7] L.E. Brus, Electron-electron and Electron-hole interaction in small semiconductor crystallite; The size dependence of the lowest excited electron [8] Invitrogen Quantum Dot Technology. http://www.qdots.com [9] Kittel Charles, ‘Introduction to Solid State Physics’, sixth edition, John Wiley and sons, Inc., New edition, John Wiley and sons, Inc., New York, Chichester, (1986), pp 299. [10] Wikepedia. http://en.Wikepedia.org [11] A. J. Nozik, ‘Spectroscopy and hot electron relaxation dynamics in semiconductor quantum wells and quantum dots’, Annu. Rev. Phys. Chem. 52, 193-231 [12] S. Sze, Physics of Semiconductor Devices, Wiley, new York, (1981). [13] A.J. Nozik, Annu. Rev. Chem., 52 (2001) 193 [14] R.T. Ross and A.J. Nozik, J. Appl. Phys., 53 (1982) 3813. {15] D.S. Boudreaux and F. Williams, A. J. Nozik, J. Appl. Phys., 51 (1980) 21581. [16] P.T. Landsberg, H. Nussbaumer, G. willeke, J. Appl. Phys. 74 (1983) 1451 [17] S. Kolodinski, J.H. Werner, T. Wittchen, H.J. Queisser, Apply. Phys. Lett. 63 (1993). [18]M..A. Green, Third Generation Photovoltaics., Bridge Printery, Sydney, 2001. [19] A.J. Nozik, Physica E, 14 (2002) [20] R. Schaller, V. Klimov, Phys. Rev. Lett., 92 (2004) 186601. [21] A. Luque, A. Marti, Phys. Rev 78 (1997) 5014 [22]L. Jacak, P. Hawrylak, and A. wojs, ‘Quantum dots’, (Springer 1998). [23] Evident Technology http://www.evidenttech.com [24] A.P. Alivisatos, J. Phys. Chem. 100,13226 (1996). [25]S.V. Gaponenko, Optical Properties of Semiconductor nanocrystals (Cambridge Univ. Press, Cambridge, 1998). conversion efficiency of photons into charge carriers. Nano Lett. 6, 424-429 (2006). [26] M. C. Hanna, and J. A. Nozik, ‘solar conversion efficiency of photovoltaic and photoelectrolysis cells with carrier multiplication absorbers’, J. Appl. Phys. 100, 074510 (2006). [27] http://rredc.nrel.gov/solar/spectra/am1.5/. [28] JK. H. Werner, S. Kolodonski and J. H. Queisser, ‘Novel Optimisation principles and efficiency limits for semiconductor Solar cells’, Phys. Rev. Lett. 72, 3851-3854 (1994). [29] W. Spirkl, and H. Ries, ‘Lumunescence and efficiency of an ideal photovoltaic cells with charge multiplication’, Phys. Rev. B 52, 11319-11325 (1995) [30]R. Brendel, J. H. Werner and J. H. Queisser.’Thermodynamic efficiency limits for semiconductor solar cells with carrier multiplication’ sol. Energy Mat. Sol. Cells 41-42, 419-425 (1996). [31] P. Wurfel, ‘Solar energy conversion with hot electrons from impact-ionization’, sol. Energy Mat. Sol. Cells 46, 43-52 (1997). pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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[32] A. de Vos and B. Desoete, ‘ On the ideal performance of solar cells with larger than-unity quantum efficiency’, Sol. Energy Mat. Sol. Cells 51, 415-424 (1998). [33] P. T. Landsberg and V. Badescu, ‘solar cell thermodynamics including multiple impact-ionization and concentration of radiation’, J.Phys. D 35, 1236-1240 (2002).

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(ICERD08031) DEVELOPMENT OF LOW COST SOLAR ILLUMINATION SYSTEM FOR HOUSEHOLD Adavbiele A.S1 and Erua J.B.2 1. Department of Mechanical Engineering, Ambrose Alli University, PMB 14, Ekpoma- Nigeria; E-mail: [email protected]; Tel: +234(0)8077729450. 2. Department of Electrical/Electronic Engineering, Ambrose Alli University, PMB 14, Ekpoma- Nigeria; E-mail: [email protected]. Tel: +234(0)8035661470.

Solar electrification to serve certain appliances, which consume less power, is highly desired and less expensive to afford in a household. The use of fewer solar cells can further reduce the cost of procuring the equipment. The main objectives of the present study were to establish the minimum numbers of cells that can illuminate a household based on certain energy requirements and the identification of best lighting appliances to maximize the energy usage. In order to achieve these objectives, experiments with various arrangements of cells, all linked to a common battery storage, were carried out and different lighting appliances, which include neon, fluorescent and light emitting diode (LED) bulbs were used.. It was found that to obtain optimum voltage-current output, a series- parallel arrangement with a geometric progression stands to give the best result. It was also established that LED bulbs consume less power. The payback period for LED bulbs operating on the system was also found to be the best for the system

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(ICERD08060) THE EFFECT OF TURBIDITY OF ABSORBING SPHERICAL DUST PARTICLES ON THE THERMAL PERFORMANCE OF A CPC SOLAR WATER HEATER

H. DAN-DAKOUTA* and A. A. ASERE* * * Mechanical / Production Engineering Programme, Abubakar Tafawa Balewa University; P.M.B. 0248, Bauchi; Bauchi state, Nigeria. ** Department of Mechanical Engineering, Obafemi Awolowo University, Ile – Ife. E-mail: [email protected]

The shift from conventional to renewable energy sources has become imperative as a result of the alarming stage of environmental pollution caused through the utilization of the conventional energy sources (such as oil, natural gas, coal, kerosene, etc.) and the depletion rate of these sources. Among the renewable energy sources (such as solar, wind, geothermal, tidal, biomass, etc.) solar appears to be the most promising alternative source of energy, especially in the tropical region of Africa. It provides for a sustainable and environmentally friendly source of energy. A major problem militating against the effective utilization of solar energy in this region is the effect of dust particles during “harmattan” period. The presence of harmattan dust particles in the atmosphere scattered and partially absorbed the solar radiation that may fall on the collector’s aperture. The study of collectors’ thermal performance in the presence of dust particles is very significant in the tropical region of Africa, since this will lead to collector’s improved design and adaptability for effective utilization of solar energy. In this work, the thermal performance of a low concentration ratio compound parabolic concentrator (CPC) solar water heater (CR = 2:1) was studied in the presence of absorbing aerosol particles of harmattan dust. The scattering of the incident solar radiation caused by the particles was analyzed using geometric optics approach. The results of the analysis showed that the influence of the linear absorption coefficient (á) of the particles on the effect of turbidity coefficient (â) on the heater’s performance is significant only at values of á ≥ 1 µm-1 for all values of â (0.01 ≤ â ≤ 0.41) studied. The effects of deposition thickness of the scattering particles and their sizes on the performance of the same heater are significantly influenced even at low values of the absorption coefficient (á 6H2O Anode reaction: 2CH3OH + 2H2O –> 2CO2 + 12H+ + 12eIV. Molten Carbonate Fuel Cell (MCFC) The electrolyte in an MCFC is a molten alkali carbonate that is retained in a ceramic matrix of lithium aluminum oxide. MCFCs have high operating temperatures (600 - 700° C) and high efficiencies. They can be operated not only with hydrogen but also with other gases including natural gas and biogas. Applications: block-type thermal power stations (electricity-heat coupling), utility power plants Cathode reaction: O2 + 2CO2 + 4e- –> 2CO32Anode reaction: 2H2 + 2CO32- –> 2H2O + 2CO2 + 4eV. Phosphoric Acid Fuel Cell (PAFC) pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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The electrolyte in a PAFC is phosphoric acid (H3PO4). Operating temperatures range between 160 - 220˚ C. Compared to other types of fuel cells (except DMFCs), PAFCs have low efficiencies. Applications: stationary electricity supply, block-type thermal power stations (electricity-heat coupling) Cathode reaction: O2 + 4H+ + 4e- –> 2H2O Anode reaction: 2H2 –> 4H+ + 4eVI. Solid Oxide Fuel Cell (SOFC) The electrolyte in this fuel cell is a solid metal oxide, usually yttrium-stabilized zirconium oxide (ZrO2). SOFCs are high-temperature fuel cells. They can be operated with hydrogen but also other gases including natural gas and biogas. Applications: block-type thermal power stations (electricity-heat coupling), utility power plants and also home electricity generation. Cathode reaction: O2 + 4e- –> 2O2Anode reaction: 2H2 + 2O2- –> 2H2O + 4eE. DC/AC Inverter The DC/AC inverter converts the direct current (DC) voltage given by either solar panel or the fuel cell into alternating current (AC) for applications that requires AC for operations as shown in figure 2 above. There are 3 types of inverters; the square wave, sine wave and quasi-sine wave inverters. In this paper the detail explanation of the 3 types of inverter is not treated. F. Other Components A complete fuel cell system for generating power and heat consists not only of the fuel cell stack, but also of a number of other components: 

The Reformer: if the fuel needed to run the fuel cell is of inadequate quality, it has to be conditioned first. This may involve reforming and CO purification as well as desulfurization and the removal of excess oxygen. In some cases, biogas is reformed to produce hydrogen for the fuel cell as shown in figure 2 above.



Heat exchangers: serve to couple out the heat generated by the cell reaction for external use.



Other power-generating components: depending on output, these may be expansion turbines, gas turbines or combined gas- and steam turbines.



Piping, pumps and condensers required for gas and heat management.



Electrical connections between system units as well as controls and interfaces

3.

APPLICATIONS OF HYDROGEN/FUEL CELL TECHNOLOGY

I. Fuel cells for portable applications For portable applications fuel cells are an alternative to typical batteries. Their major advantage is that, unlike batteries, they do not discharge. Batteries are energy storage devices, the electrical energy they can supply is determined by the amount of chemical reactant stored within. When its reactant is used up a battery pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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has to be either recharged (if it is rechargeable) or discarded. Fuel cells, on the other hand, are energy conversion devices and do not store their own fuel. They will provide electrical energy for as long as they are supplied with fuel (hydrogen or methanol). There is a wide range of possible applications of fuel cell technology for portable devices, for example, fuel cells could provide electricity to low-power devices such as laptops or measuring instruments, or they might even supply power to camping equipment. Low-temperature fuel cells like PEMFCs and DMFCs are the most suited for portable low-power devices because they are operable at low temperatures, work immediately after start-up (i.e. no warm-up phase is required) and allow for a compact design. The only byproduct of a PEMFC is water while a DMFC - in addition to water - also produces small amounts of carbon dioxide. II. Fuel cells for mobile applications Mobile applications are dominated by PEM fuel cells. Since they have low operating temperatures PEMFCs can deliver power immediately after start-up. This is particularly important for use in automobiles. Power needs for mobile applications range from a few kilowatts to several megawatts. Small boats typically require onboard power supplies of a few kilowatts while electric power on the order of megawatts is needed to equip a submarine with adequate propulsion as well as on-board electricity and emergency energy supply systems. Due to their modular character fuel cell stacks can be adapted to meet the most different power requirements imaginable. The HydroGen3 made by Opel is powered by a fuel cell stack consisting of 200 individual fuel cells that are connected in series. As there are no moving parts in a fuel cell the energy conversion is done noiselessly and without wear and tear. BMW and DaimlerChrysler, in their research prototypes, use different technologies: The BMW 745h uses a hydrogen combustion engine instead of a fuel cell stack and an electric motor. This technology is based on the conventional four-stroke internal combustion engine, the difference being that the engine burns hydrogen instead of gasoline. The engine has a capacity of up to 135 kW. The NECAR5 (NECAR - New Electric Car), DaimlerChrysler’s fuel cell car, runs on methanol that is reformed onboard. In a reformer hydrocarbons like methanol are transformed into hydrogen, CO2 and CO. In this way the hydrogen for the fuel cell is produced directly in the automobile. III. Fuel cells for stationary applications Stationary applications range from in-home power and heat generation (output starting at 2 KW) to heat and power supply for entire residential areas by means of heat-and-power block units (with outputs in the MW range). Conventional block-type thermal power stations, which generate electrical power and heat through coupling rely on combustion engines and gas turbines. In comparison, fuel cells have much higher efficiencies as well as lower emissions and sound pollution. 4. SOLAR HYDROGEN FUEL CELL MARKET. The potential of the hydrogen fuel cell market is immense. It is the next fundamental technology change. One estimate by “future perspective on Lithuanian Research in Sustainable Energy Technologies” suggests that global demand is projected to reach €39 billion by 2011 and the potential for 2021 could exceed €2.22 trillion. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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US: Industrial activity spreads across all fuel cell and hydrogen technology development areas. The US fuel cell industry covers all technologies and many American companies are world leaders in their particular technology area. In comparison to their European counterparts, they generally have more access to venture capital funds and consequently tend to be the leaders in their fields:  Praxair is a leading industrial gas and hydrogen supplier.  Air Products produces hydrogen and equipment for hydrogen separation and purification.  Fuel Cell Energy has been developing micro fuel cell technology since the 1970s.  UTC Fuel Cells is presently the leading manufacturer of commercial stationary fuel cell systems.  Plug Power is a leader in the development of small stationary fuel cell systems.  General Motors has announced that it employs 600 people in FCV development, assembly and testing. Together, these companies cover the whole hydrogen economy value chain. Canada has been a world leader in H2/FC technology R&D - spanning most fuel cell types, components and systems supply, systems integration, fuelling systems and storage, as well as engineering and financial services. There are currently 17 companies across Canada whose primary focus or goal is fuel cell production and/or system integration. In addition, many other companies are active in the sector supplying the fuel cell producers. Canada has also been successful in encouraging H2/FC cluster development. The Vancouver area has the largest cluster of fuel cell companies, suppliers, infrastructure developers and service providers (possibly the largest concentration of fuel cell expertise in the world). Fuel cell industry clusters are also growing in the Calgary, Toronto, Kingston and Montreal areas. Canadian industry at a glance: The 2004 Sector Profile shows strong growth in many key indicators for the period 2002–2003.  Revenue has grown 40% from €115 million in 2002 to €161 million in 2003.  R&D expenditures have increased 5% from €236 million in 2002 to €248 million in 2003.  Employment stands at 2,685, a modest decrease from 2002 levels.  Participation in demonstration projects has increased by 232% to 262 in 2003 from 79 in 2002.  Patent holdings are up by 34% to 581 in 2003. In 2003, the following countries established the International Partnership for Hydrogen Economy (IPHE): Australia, Brazil, Canada, China, European Commission, France, Germany, Iceland, India, Italy, Japan, Norway, Russian Federation, United Kingdom, South Korea, and USA. These countries represent:  $35 Trillion, or 85% of world GDP  ~ 3.5 billion people  75% of worldwide electricity used  2/3 of energy consumption and CO2 emissions The vision of IPHE is that “…consumers will have the practical option of purchasing a competitively priced hydrogen powered vehicle, and be able to refuel it near their homes and places of work, by 2020.” 5. CONCLUSION It is clear that solar-powered hydrogen energy system is technologically feasible. Several pilot plants were built in the mid-1990’s up till 2007 with solar arrays coupled to electrolyzers, and fuel cell. The real question is “will this technology ever be economically feasible.”? It is clear that currently, the technology is far too expensive to compete with cheap fossil fuel based electricity and hydrogen production methods. However, it is also clear that with learning curve based cost-reductions and a steadily growing market for photovoltaic cells that Si solar cell based photovoltaic electricity will very likely be cost-effective by around 2020.

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PEM electrolyzer costs will decrease by the same driving forces provided that a market develops in which they can gain significant production volume. It appears that such a market is developing as large-scale hydrogen development projects such as California’s Hydrogen Highway” are beginning to order PEM electrolyzer systems for refueling stations. This evidence of an emerging market, coupled with the fact that PEM electrolyzer development will benefit in lock-step with inevitable developments in PEM fuel cell technology as the U.S. hydrogen energy economy continues to evolve, bodes extremely well for the future of PEM electrolysis technology, as well as distributed photovoltaic-electrolyzer technology as a whole. 6. REFERENCES [1] Tores, L.A Rodriguez, F.J., Sebiastian , P. J., Simulation of a solar – hydrogen-fuel cell system: Results for different locations in Mexico, Int .Journal of Hydrogen Energy, Vol.23, pp 1005-1009, 1998 [2] Wallmark , C., Alvors, P ., technical design and economic evaluation of a stand-alone PEFC system for buildings in Sweden ,Journal of Power Sources 118(2003)358-366 [3] Vosen, S.R. Keller, J.O., hybrid energy storage systems for stand –alone electric power systems: optimization of system performance and cost through control strategies , Int . Journal of Hydrogen Energy , Vol. 24, pp. 1139-1156,1999. [4] Kolhe, M. , Agbossou , K. ,Hamelin ,J. ,Bose, T.K, Analytical model for predicting the performance of photovoltaic array coupled with a wind turbine in a stand-alone renewable energy system based on hydrogen, Renewable Energy, Vol.28, pp.727-742,2003. [5]El-Shatter,Th.F.,Eskandear,M.N.,El-Hagry, M.T., Hybrid PV/fuel cell design and simulation, Renewable Energy, Vol.27,pp.479-485, 2002.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

TECHNICAL SESSION 1C: MATERIALS AND PROCESSING I

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(ICERD 08028) Corrosion Behaviour of Aluminium 1017 in Domestic Food – Cooking Environment S.A. Balogun1, *D.E.Esezobor2 and S. O. Adeosun3 Department of Metallurgical and Materials Engineering, University of Lagos, Akoka -Yaba, Lagos, Nigeria 1 [email protected] 2 [email protected] 3 [email protected] Abstract Deep drawn aluminum utensils are used widely for domestic cooking in the third world countries. Such utensils are subjected to several heating cycles during their service lives. In aggressive cooking environment the aluminum is very prone to localized attack. The material is noticed to fail progressively due to the appearances of pits which eventually shorten the service life of aluminum cooking utensils. This paper examines the corrosion behaviour of aluminium (AA 1017) alloy in different domestic food – cooking at a temperature other than ambient temperature. The annealed aluminum alloy, which was heated and left standing in the air showed a higher cumulative corrosion rate when placed in lycopersicum esculentum solution than in capsicum annum or allium cepa solutions. The specimen heated and then super cooled in a refrigerator showed remarkably low level of corrosion in the 288 – hour duration of the experiment. Key word: allium cepa, capsicum annum, deep drawn aluminum alloy, cooking utensil, corrosion pitting, corrosion rate, lycopersicum esculentum, refrigeration 1

Introduction

Deep drawn aluminium utensils are used widely for domestic cooking in the third world countries. Such utensils are subjected to several heating cycles during their service lives. In aggressive cooking environment the aluminium is very prone to localized attack. The material is noticed to fail progressively due to pitting corrosion which eventually shortens the service life of aluminium cooking utensils. Studies revealed that aluminium alloy cookware and containers – cooking utensil and aluminium beverage cans contribute substantially to consumption load of aluminium [1, 2]. In the study conducted at the University of Cincinnati Medical Center [3] acid – forming foods dissolve aluminium more rapidly. It found out that tomatoes cooked in an aluminium pot had a 2 to 4 milligram increase in aluminium content in serving. The corrosion products particles leach from the utensil into the foods being cooked. Laboratory research has shown that healthy human body can handle up to twenty milligrams of aluminium ingestion per day [1]. The absorbed aluminium is eliminated through the kidney in form of urine and unabsorbed aluminium is excreted in the faeces. [4, 1]. Unfortunately, the activity of the kidney decreases with age [4, 5]. At 65 years and above, the ability of the kidney to eliminate aluminium diminishes [5], resulting to the accumulation of these particles in the body. They are distributed mainly in bone, liver, testes, kidneys and brain [1, 4]. Numerous studies have indicated that aluminium accumulates in the body, especially in nerves tissues potential causing harm [1, 2, 6 – 8]. Scientists have established a link between aluminium and Alzheimers diseases, the commonest cause of senile and presenile dementia, clumsiness of moments, staggering when walking and inability to pronounce words properly [6 - 9]. Dementia is an ailment where the patient exhibits progressive loss of memory and other higher mental functions as a result of the brain cells and the development of plaques and tangles [3, 6, 7, 9]. Behavioural difficulties among school children have also been correlated with elevated levels of aluminium and other neurotoxic heavy metals [8]. And the toxicity may also cause birth defects in newborns [1]. Thus, the determination of the rate of pit-aluminium particles in cooking utensils has become imperative in order to prevent mental degradation in human beings especially in the third world countries.

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Corrosion rates can increase from a low rate to several thousand mils per year as a result of increasing temperature. [10]. Microorganisms can also affect corrosion behaviour in a number of ways. They may produce slimes and deposits, which give rise to crevice corrosion, by creating corrosive conditions through their metabolic products. They may destroy materials added to the system to provide corrosion inhibition and they may directly influence the corrosion reactions. The operating conditions that affect microbiologically induced corrosion (MIC) of materials include flow rate (velocity), temperature, pressure, pH, oxygen level and cleanliness of the system and water. MIC-related bacterial growth typically occurs in systems within specific temperature ranges, depending on the bacteria [11]. The range is often reported as being between 4 to 49oC. More than 90% of MIC is seen as pitting-type corrosion. This is due to the fact that most microbiological community usually remains fixed to the colonization site. Aluminium is known to corrode non-uniformly because of preferential attack on grain boundaries, which results in a symptomatic feature- appearance of a second time constant in the low frequency region of the phase angle diagram [12]. Increase in aluminium oxide layer resistance and decrease in the layer thickness implies that microorganisms might act as passivity promoters at the site of localized corrosion attack (passive layer defects, pores, micro cracks, etc). The susceptibility of aluminium to localized corrosion makes it particularly vulnerable to MIC. There are two mechanisms for MIC that have been documented for aluminium and its alloys; production of water- soluble organic acids by bacteria and fungi, and the formation of differential aeration cells [13]. Free corrosion often leads to the formation of pits, while tunnels may form under either potentiostatic or galvanostatic control. Pits have been noted during natural corrosion of aluminium in fresh water or chloride media. Pits also form under potentiostatic or intentiostatic control in NaCl or KCl solutions while, tunnels are noticed during natural corrosion of aluminium in chloride media, or under potentiostatic control in KCl or NaCl solutions [14]. Pit generally entails cavities of similar width and depth, while tunnel refers to holes with a depth much larger than the diameter. The effects of potential, temperature, chloride concentration, pH and speed of rotation of the electrode on aluminium alloy have been systematically studied [15]. The shape of the current - time curves is relatively insensitive to variations of the investigated parameters. Study on corrosion of deep drawn AA 1017 and cast AA 6063 in lycopersicum esculentum (tomatoes) at a temperature other than ambient temperature has revealed that cast cylindrical utensils pit much more readily than deep drawn utensils [16]. The pits noticed in cast utensil is traceable to the presence of micro-cracks as a result of hydrogen embrittlement phase, precipitation of brittle second phase particles, and the fine texture in cast utensil. The study also revealed that the deformation of AA 1017 and its subsequent annealing helped to improve its corrosion resistance in L. esculentum solution during domestic heating cycles. This paper examines the corrosion behaviour of aluminium (AA 1017) alloy in different domestic food – cooking environments at high, room and refrigeration temperatures. 2

Experimental Methodology

Test specimens were obtained from a 40 cm diameter cold and hot rolled annealed aluminium circular blank sheet, provided by Aluminium Rolling Mills Ota, Ogun State, Nigeria. Table 1 shows the composition of the aluminium alloy (AA 1017) evaluated in this study.

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AA 1017 specimens with dimension 50 mm x 50 mm x 1.2 mm were subjected to 250 ml solutions of capsicum annum, L. esculentum, allium cepa, and to the mixture of these fruits products. Using Jenway 350 meter, the pH of the solution was recorded. The specimens were subjected to three different tests which involve: Heating the specimen in solutions for 20 min, cooling at 300C and super cooling at 40C (under refrigeration) Heating the specimens for 20 min, cooling at 300C without super cooling Control test (specimen at room temperature of 300C At the end of the tests, one surface of each specimen was prepared for metallographic examination using a mixture of nitric acid, hydrofluoric acid, and water as etchant for about 50s. Table 1 Chemical Analysis of aluminium alloy blank sheet Element Al Si Cu Mn Mg Zn Wt, % 99.06 0.23 0.56 0.05 tw

399

2.2b

Where tw is the time when the oil that embedded the particles is extracted, c* the equilibrium concentration of the essential oil in SC CO2 on SC phase-essential oil interface, ce the essential oil concentration in SC phase at the duct end, aw the specific surface of wetted particles referred to SC fluid volume and it is dependent on time, position in the extractor and the quantity of oil that surrounds the particles, ad the specific surface of open duct ends available for mass transfer referred to SC fluid volume and K is the mass transfer coefficient through the SC film surrounding the particles. Specific surface for SFE from the ducts was calculated from: 2

2 N d d / 2   ad  VE 

2.3

where N is the number of secretory ducts, dd the secretory duct diameter, å the void fraction of the bed and VE is the volume of extractor vessel. Specific surface of wetted particles was calculated from:

aw 

31    RW 

2.4

Where RW is the radius of wetted particle. All particles are equally wetted and the oil film thickness around each particle is the same at the beginning of SFE. For each time and space increment RW can be obtained from:



dRW k  c * c sf  dt csat

2.5

Where csat is the essential oil concentration in the oil film around particle which is constant and equal to the concentration of the oil in liquid phase saturated with CO2. The volume of the extractor VE is obtained from:

DE2 VE  L 4

2.6

where DE is the diameter of the extractor vessel. 2.2 Solution of the Model Equation 2.1 was solved using the Crank-Nicolson procedure (a finite difference technique) [33]. The rectangular domain of the function is overlaid by a grid whose mesh size is of h units in the x direction and k units in the y direction. The value of csf(x, t) at the ijth grid point is denoted by:

cisf, j  c sf ih, jk 

2.7

According to this technique the equation 2.1 evaluated at the ijth grid point is:

c sf t

i, j 

1 2

 Dl

 2c sf x 2

u i, j 

1 2

c sf x

i, j 

1 2

2.8

 ST i , j  1 2

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The finite difference equation for the first partial derivative of csf(x, t) with respect to time can be written as:

c sf t

 i, j 

cisf, j 1  cisf, j

2.9

k

1 2

The second partial derivative of csf(x, t) with respect to distance x may be written as:

 2c sf x 2

 cisf1, j  2cisf, j  cisf1, j    2 1 h    sf sf sf 2 c  2ci , j 1  ci 1, j 1    i 1, j 1  h2  

1 i, j  2

2.10

while the first partial derivative of csf(x, t) with respect to distance x may be written as:

c sf x

i, j 

1 2

 cisf1, j  cisf1, j    1 2h    sf sf  2 c c   i 1, j 1 i 1, j 1  2h  

2.11

Two separate finite difference equations can be written for the Source and Transfer term ST. These are:

ST i , j  1  aw K c *  cisf, j 2





for ttw

2.12



for t>tw

2.13

and

ST i , j  1  ad K c e  cisf, j 2



Substituting equations 2.9, 2.10, 2.11, 2.12 and 2.13 in equation 2.8 gives the following finite difference equations:

cisf, j 1  cisf, j k

sf  Dl  ci 1, j  2ci , j  ci 1, j   2 2h   cisf1, j 1  2cisf, j 1  ci 1, j 1 

u sf ci 1, j  cisf1, j  cisf1, j 1  cisf1, j 1 4h  aw K c * cisf, j 







2.14



and

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria cisf, j 1  cisf, j k

sf  Dl  ci 1, j  2ci , j  ci 1, j   2 2h   cisf1, j 1  2cisf, j 1  ci 1, j 1 

u sf ci 1, j  cisf1, j  cisf1, j 1  cisf1, j 1 4h  ad K c e  cisf, j 

401







2.15



for ttw and t>tw, respectively. This model was applied on experimental data of fennel fruit essential oil SCE at 313K and 10MPa obtained by Sovova et al. [34]. The average duct diameter is 70 m [5]. Substituting the relevant values of k, h, Dl, u, K, ad, aw, c* and ce leads to the following set of equations:

 cisf, j 1  7.5 E  7 cisf1, j 1  2cisf, j 1  cisf1, j 1



 5.41E  5 cisf1, j 1  cisf1, j 1







 cisf1, j    0.78181c  7.5 E  7   2c sf  c sf  i, j i 1, j   sf i, j

 5.41E  5 cisf1, j  ci 1, j



2.16



 2.6183E  3 and

 cisf, j 1  7.5E  7 cisf1, j 1  2cisf, j 1  cisf1, j 1





 5.41E  5 cisf1, j 1  cisf1, j 1



 0.999973cisf, j  5.41E  5 cisf1, j



  7.5E  7c c 

sf i 1, j

 2cisf, j  cisf1, j



2.17

i 1, j

 4.306E  7 for ttw and t>tw, respectively. Equations 2.16 and 2.17 were applied to the grid points to yield a set of simultaneous equations which were then solved using MS Excel spreadsheet. The solution of the simultaneous equation gives the values of the concentration of essential oil csf in the supercritical phase at the various grid points.

3.0 3.1

RESULTS AND DISCUSSION Results

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C o n c e n tr a tio n (m o l/m 3 )

0.0120 0.0100 0.0080 Expt. Model

0.0060 0.0040 0.0020 0.0000 0.00

1.00

2.00

3.00

Time (hr)

Fig. 3.1: Supercritical Fluid Extraction of Essential Oil at 313K and 10MPa from Fennel fruit as a function of time.

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Table 3.1: Solution of the model. t(hr)\x(m)

0.00

0.40

0.80

1.20

1.60

2.00

0.00

0.0000

0.00000000

0.00000000

0.00000000

0.00000000

0.00000000

0.25

0.0000

0.00261816

0.00261830

0.00261830

0.00261830

0.00261830

0.50

0.0000

0.00466480

0.00466531

0.00466531

0.00466529

0.00517850

0.75

0.0000

0.00626469

0.00626569

0.00626569

0.00626569

0.00626569

1.00

0.0000

0.00751534

0.00751688

0.00751688

0.00751688

0.00751688

1.25

0.0000

0.00849299

0.00849507

0.00849507

0.00849507

0.00849507

1.50

0.0000

0.00925723

0.00925983

0.00925983

0.00925983

0.00925983

1.75

0.0000

0.00925640

0.00926001

0.00926001

0.00926001

0.00926001

2.00

0.0000

0.00925557

0.00926019

0.00926019

0.00926019

0.00926019

2.25

0.0000

0.00925474

0.00926037

0.00926037

0.00926037

0.00926037

2.50

0.0000

0.00925391

0.00926055

0.00926055

0.00926055

0.00926055

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3.2 Discussion Table 3.1 shows the result of the mathematical modeling of the supercritical carbon dioxide extraction of essential oil from fennel fruit. The model was applied to experimental data obtained by Sovova et. al. [34]. Fig. 3.1 shows the variation of concentration of essential oil extracted with time at the outlet of the extractor for both the model and that obtained by experiment. As can be seen, the presented model simulates experimental data of SFE from secretory ducts with good accuracy. Change of the extraction mechanism from the first period, in which the oil is being extracted from the film embedding the particles, to the second one, in which the oil is being extracted from the ducts, is clearly visible on the simulated curve (curve bending at t = 30 minutes). As can be seen from Fig. 3.1, the first extraction period (t < 30 minutes) is characterized by a relatively fast mass transfer resulting in significant increase of the oil concentration in SC CO2. As the film surrounding the particles is being extracted, the second mechanism of the extraction from externally dry particles commences (extraction from the ducts). This start of the second mechanism can be seen on Fig. 3.1, and is characterized by a slower mass transfer resulting in a slower increase in oil concentration; and the slope of curve is less steep than in the first mechanism (extraction from the embedding film). During this period of SFE both of the extraction mechanisms, from the surrounding film as well as from the ducts, are present in the extraction vessel. After a certain time of extraction, the films of surrounding oil are extracted along the entire vessel length, and the extraction is now proceeding by the second mechanism in the entire vessel (extraction from the ducts). Fig. 3.1 indicates that the extraction from the embedding film is a much faster process than the extraction from ducts, since the fraction of essential oil embedding the particles is small compared to the fraction remaining within the ducts and the extraction mechanism transition occurs in relatively short time. This transition resulted in the bended form of the simulated extraction curve. After approximately 1 hr 45 minutes, nearly all the oil has been extracted and there is little change in the concentration of essential oil in SC CO2 with time. This is represented by the nearly horizontal portion of the curve. The total extraction time was two and half hours. These results are confirmed by Zizovic et. al. [21]. Table 3.1 shows the essential oil concentration profile along the length of the extractor vessel. As can be seen, the extraction of essential oil at different points along the length of the extractor vessel takes place independently, indicating the efficiency of the supercritical fluid extraction process. The essential oil concentration profile at different points along the length of the extractor vessel are similar. Similar results were obtained by Zizovic et. al [21]. 4.0 CONCLUSION Modeling of supercritical carbon dioxide extraction of essential oil at 313K and 10MPa from milled fennel fruit has been carried out. A model was developed and solved using the Crank-Nicolson finite element procedure. The resulting simultaneous equations were implemented on MS Excel Spreadsheet. The result of the model predicts the essential oil concentration, in the supercritical carbon dioxide phase, at different points along the length of the extractor vessel and at different times. The suggested model showed good agreement with experimental data confirming the basic hypothesis of the model - the oil embedding the milled seed particles is extracted first, followed by the extraction of the oil inside the ducts in the secretory structures and also the efficiency of the supercritical fluid extraction process. REFERENCES 1. Jessop, P. G., W. Leitner, Chemical Synthesis Using Supercritical Fluids, Wiley-VCH, Weiheim, (1999). 2. Supercritical Fluids, Chem. Rev., Special Thematic Issue, 99(2), (1999). 3. Clifford, A. A., C. M. Rayner, Potential Tuning of Reactions in Supercritical Fluids, Proceedings of the 5th International Symposium of Supercritical Fluids, Atlanta, (2000).

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4. Croteau, R., Biochemistry of Monoterpenes and Sesquiterpenes of the Essential Oil. Herbs, Spices and Medicinal Plants: Recent advances in botany, horticulture, and pharmacology. Vol. 1: 81-135, Oryx Press, Phoenix, AZ, (1986). 5. Svoboda, K. P., Svoboda, T. G., Secretory Structures of Aromatic and Medicinal Plants, A review and Atlas of micrographs, Microscopix Publications, Knighton UK, (2000). 6. Landing. J. E. American essence: A History of the Peppermint and Spearmint Industry in the United States. A. M. Todd Foundation, Kalamazoo, MI, (1969). 7. Ellis, N. K., K. I. Fawcett, F. C. Gaylord and L. H. Baldinger, A study of some of the factors affecting the yield and market value of peppermint oil, Purdue University, Bull, p. 461, (1941). 8. Heath, H. B., Source of Flavours, AVI, Westport, CT, (1981). 9. Lawrence, B. M., A Review of the World Production of Essential Oils, Perf. & Flav., pp. 10:1-16, (1985). 10. Encarta Encyclopedia, Microsoft student with Encarta premium 2007 DVD. Redmond, WA: Microsoft Corporation, (2007). 11. Guenther, E., The Production of Essential Oils: Methods of Distillation, enfleurage, maceration, and extraction with volatile solvents, in: Guenther, E. (ed), The essential oils, History-origin in plants, production analysis, Vol. 1: 85-188, Krieger Publ. Co., Malabar, FL, (1972). 12. Runeckles, V. C. and T. J. Mabry (eds), Terpenoids: Structure, Biogenesis, and Distribution, Academic Press, NY, (1973). 13. Perry, R. H. and C. H. Chilton, Chemical Engineers’ Handbook, seventh edition, McGraw Hill, New York, pp. 22/14 – 22/18, (1998). 14. Liong, E. J., U. V. Wells, and G. J. Foster, J. Supercritical Fluids 4, 91 (1991) 15. Sovova, H., Rate of Vegetable Oil Extraction with Supercritical CO2 – Modelling of Extraction Curves, Chem. Eng. Sci., Vol. 49, pp. 409-414, (1994). 16. Reverchon, E., Donsi, G., Sesti, O., Modelling of Supercritical Fluid Extraction from Herbaceous Matrices, Ind. Engng. Chem. Res., Vol. 32, pp. 2721-2726, (1993). 17. Reverchon, E., Sesti, O. L., Supercritical CO2 Extraction of Basil Oil: Characterization of Products and Process Modelling, Journal of Supercritical Fluids, 7, 185-190, (1994). 18. Reverchon, E., Sesti Osseo, L., Modelling the Supercritical Extraction of Basil Oil, in: M. Perrut, G. Brunner (Eds.), Proceedings of the Third symposium on Supercritical fluids, 2, 189, (1994). 19. Reverchon, E., Mathematical Modelling of Supercritical Extraction of Sage Oil. AlChE Journal, 42, 1756-1771, (1996). 20. Zizovic, I., Stamenic, M.,Orlovic, A., Skala, D., Supercritical carbon dioxide extraction of essential oils of Lamiaceae family species-Mathematical modelling and optimization, 16th International Congress of Chemical and Process Engineering – CHISA 2004, Praha, C8.4, 498, (2004). 21. Zizovic, I., Stamenic, M., Orlovic, A., Skala, D., Supercritical Carbon Dioxide Essential Oil Extraction of Lamiaceae Family Species – mathematical modelling on the micro-scale and process optimization, Chem. Eng. Sci., 49, 409-414, (2005). 22. Gang, D. R., Wang, J., Duradeva, N., Nam, K. H., Simon, J. E., Lewinsohn, E., Pichersky, E., An Investigation of the Storage and Biosynthesis of Phenylpropenes in Sweet Basil. Plant Physiology 125, 539-555, (2001). 23. Turner, G. W., Gershenzon, J., Croteau, R. B., Development of Peltate Glandular Trichomes of Peppermint, Plant Physiology 124, 665-680, (2000). 24. Turner, G. W., Gershenzon, J., Croteau, R. B., Distribution of Peltate Glandular Trichomes on Developing Leaves of Peppermint, Plant Physiology 124, 655-663, (2000). 25. Werker, E., Putievsky, E., Ravid, U., Dudai, N., Katzir, I., Glandular Hairs and Essential Oil in Developing Leaves of Ocimum basilicum L. (Lamiaceae), Annals of Botany 71, 43-50, (1993). 26. Bouwmeester, H. J., Gershenzon, J., Konings, M. C. J. M., Croteau, R., Biosynthesis of the Monoterpenes Limonene and Carvone in the Fruit of Caraway. Plant physiology, 117, 901 – 912, (1998).

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27. Sarafis V., Rumpel H., Pope J., Kuhn W., Non-invasive Histochemistry of Plant Materials by Magnetic Resonance Microscopy. Protoplasma, 159, 70 – 73, (1990). 28. Gersbach P. V., Reddy N., Non-invasive Localization of Thymol Accumulation in Carum copticum (Apiaceae) Fruits by Chemical Shift Selective Magnetic Resonance Imaging. Annals of Botany, 90, 253-257, (2002). 29. Pasqua G., Monacelli B., Silvestrini A., Accumulation of Essential Oils in Relation to Root Differentiation in Angelica archangelica L., European Journal of Histochemistry, 47, 87-90, (2003). 30. Lersten N. R., Curtis J. D., Foliar Oil Reservoir Anatomy and Distribution in Solidago copticum (Asteraceae, tribe Asterae). Nordic Journal of Botany, 9, pp. 281 – 287, (1989). 31. Lotocka, B., Geszprych A., Anatomy of the Vegetative Organs and Secretory Structures of Rhaponticum Carthamoides (Asteraceae), Botanical Journal of the Linnean Society, 144, 207 – 233, (2004). 32. Melo-de-Pinna G. F. A., Menezes N. L., Meristematic Endodermis and Secretory Structures in Adventitious Roots of Richterago Kuntze (Mutisieae-Asteraceae), Revista Brasil Bot. 26, 1 – 10, (2003). 33. Stroud, K. A., Advanced Engineering Mathematics, fourth edition, Palgrave Macmillan, Hampshire, pp. 517 – 565, (2003). 34. Sovova, H., Komeres, R., Kucera, J., Jez, J., Supercritical Carbon Dioxide Extraction of Fennel Essential Oil, Chem. Eng. Sci., 49, 2499 – 2505, (1994). 35. McCabe, W. L., J. C. Smith, P. Harriott, Unit Operations of Chemical Engineering, sixth edition, McGraw Hill, pp. 766-767, (2001). 36. Himmelblau, D. W., Basic Principles and Calculations in Chemical Engineering, sixth edition, Prentice-Hall, India, p. 282, (2002).

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407

(ICERD 08222) The Study of Biogeoavailability of Calcium in Cement Industry Environments of North Eastern Zone of Nigeria.

A.I Inegbenebor, Dept. of Chemistry, Covenant University, Canaan Land, Ota, Ogun State.

Abstract From the on-going observations and prediction in this work, the results show that secondary carbonate minerals, especially those of the common base metals such as magnesium, lead and zinc may be found in Gombe-Bauchi orebodies include associate minerals. The associate minerals that may be found are hydrozincite, Zn5(Co3)2(OH)6, hydrocerussite, Pb(CO3)2 and the very rare mineral plumbonacrite PbOO(OH). In accordance with the statiscal interpretation of the results. The standard deviation were identified as action 

line X  3 / n , which is equivalent to 59.16 and 49.84 g / ml , while two standard error as warning 

lines, that is X  2 / n resulting in 58.91 g / ml . The expectation of these minerals in abundance depends on the ratio of (Ca2+)/a(Mg2+), a(Ca2+)/a(Zn2+) and a (Ca2+) /a(Pb2+) Introduction Calcarous carbonates ores such as limestone, marbles, coral reefs are ubiquitous in nature [1]. These minerals represent enormous deposits of such sample salt as calcite, aragonite, dolomite and the like. In addition, CO2 can be introduced from the atmosphere via rainwater forming other carbonate compounds in the deposits. Calcium containing ores undergo total dissolution in their ionic form and ore readily available for plants and vegetable. Some sources of calcium in vegetable for human taken into consideration in this study include nuts, cabbage, greens and soyabean. Other good sources of calcium in vegetation are yeast, figs, kelp, dark leafy. Calcium may also be derived from a variety of herbs, spices and seaweeds [2]. In the cement industry environ, it is a common thing to see some vegetations blossom and others are dried due to the activities the calcareous carbonates that are released from the industry. Some plants in such area of the activities can indicate minerals prospect which may be useful to the country, Inegbenebor and Akinniyi [3-4]. The vegetation at Ashaka Cement industry environ in Gombe of the North East zone of the country, looks greenish throughout the year even though the industry is situated in the aridzone region. This observation prompt this study of biogeoavailability of calcium and other elements that are present at the ore-bearing bed, to the water-table and the plant roots, as a results of the activities of the industry. Therefore, the aim of this work was to make an assessment of precision of the levels of the element in Nigeria Cement industry orebodied areas, under normal, high and low level conditions, in order to exploit for other minerals. Experimental Method The area covered was the township section which lies along north-south and east-west borders of the Ashaka Cement industry. The orientation study include observations on the extent, depth and inclination of orebodies, the probable grade of the ore and the relation of the ore- bearing bed to the water-table and the plant roots. The vegetation studied were made of the growth habits of the sesamum (Acta), sorghum, soyabean

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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nuts, and dark leafy, species available for sampling. The preliminary samples were collected on both mineralized and unmineralized ground. These were analysed to determine the amounts of the elements absorbed by the plants in the area under study, using usual analytical methods [3]. All other chemical analysis were carried using the necessary reagents. The results were analysed by using statistical method.

Result and discussion The results of calcium from the oxidized zone areas are deduced from the analysis applications which are translated into various mean and bar charts. The standard errors, which also refers to the standard deviation 

as action line were identified as action line at X  3 / n , which is equivalent to 59.16 and 49.84 g / ml , 

while two standard error as warning lines, that is, X  2 / n resulting in 58.91 g / ml . High level of calcium in vegetable in the cement environs can increase the likelihood of toxic reaction from the environment which can be detrimental to vegetable and human [2]. As a result of the high level, it is also worth pointing out that the secondary calcareous carbonate minerals such as hydrocerussite, Zn5(CO3)2(OH)6, hydrocerussite, Pb3(CO3)2(OH)2, plumbonacrite,PbOO(OH)6 might be expected at Gombe-Bauchi environment. These depends on the ratio of a (Ca2+)/a(Mg2+), a(Ca2+)/a(Zn2+) and a(Ca2+)/a(Pb2+) as predicted in this. Conclusion The on-going observations and discussion on carbonate minerals especially those of the common base metals suggested that magnesium, lead and zinc containing secondary ores may be found in Gombe-Bauchi orebodied, with associate other minerals. Reference 1. Williams, P. A. (1990), Oxide-zone Geochemistry (Ellis Harwood, Chichester), 241. 2. Thys – Jacobs, S. (2000) Micronutrients and Premenstrual Syndrome: The Case for Calcium I. Am. Cell Nutri. 19(2) 220-227. 3. Inegbenebor, A. I. and Akinniyi, J. A. (2001), Nigeria Journal of Applied Science, Vol. 20, pp100. 4. Cannon, H. L. (1960) Botanical Prospecting for Ore Deposits, Science, 132, 3427(591-598). 5. Kooh, G. S. and Link, R. F. (1970) Statistical Analysis of Geological Data, Vol. 1 365pp. 6. W.H.O (1996), Trace Element in Human Nutrition and Health Publications, pp50, 228 Geneva. 7. Recommended Health Based Limits on Occupational Exposures to Heavy Metals, Tech. Report Series. Pp647.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

409

(ICERD08226) ADOUCISSEMENT DES EAUX DURES PAR LE PHOSPHATE MONOSODIQUE A. S. Manzolaa*, A. Mgaidib and M. El Maaouib a

Laboratoire de Chimie Analytique et Minérale ; Faculté des sciences ; Université Abdou Moumouni BP 10662 Niamey Niger. Tel : 0022720315072 Fax : 0022720315862 Email : [email protected] b Laboratoire de Chimie Minérale Industrielle ; Faculté des sciences ; Université de Tunis El Manar BP 37 El Belvédère 102 Tunis Tunisie. Les phosphates ont été largement utilisés pour adoucir les eaux dures de process et de boisson. Pour les eaux de boisson le taux de phosphate admissible après traitement est de 5 mg/L de P2O5 (norme internationale exigée). Notre travail a consisté à étudier la précipitation des ions Ca2+ et Mg2+ par du phosphate monosodique dihydraté. Le traitement d’un litre d’eau contenant 1000 mg de Ca2+ et 50 mg de Mg2+ permet d’éliminer 82, 69 % de Ca2+ et 20, 76 % de Mg2+. Cette eau traitée ne contient que 5 mg/L de P2O5, ce qui correspond à la norme internationale exigée. Les précipités obtenus ont été identifiés par analyse chimique, spectroscopie FTIR, Diffraction aux Rayons X, Analyse Thermogravimétrique (ATG) et Analyse Thermique Différentielle (ATD). Les précipités obtenus évoluent avec le pHo. Il s’avère que le DCPD précipite aux pHo allant de 5 à 6,6 ; le TCP et autres apatites au delà de pHo = 7. Le DCPD (Phosphate Dicalcique Dihydraté : CaHPO4.2H2O) précipité est un produit pur qui peut être utilisé en nanotechnologie et en biomédicale.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

410

TECHNICAL SESSION 3B: METAL WORKING PROCESSES

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

411

(ICERD08008) SPLATTERING OF IMPINGING LIQUID JET ON A FLAT PLATE OR PIPE SURFACE

George E. NKENG and Philip F. NOLAN Faculty of Science, University of Buea, P.O Box 63, Buea, Cameroon, or ENSTP, B.P. 510 Yaounde, Cameroon. ** Chemical Engineering Research Centre, School of Applied Science, South Bank University, 103 Borough Road, London SEI OAA, UK. *

Address for Corresponding Author: ENSTP B.P. 510 Yaounde, Cameroon Tel: 00 237 22 23 09 44 / 77 70 05 07 Fax: 00 237 22 22 18 16 Email: [email protected]

An experimental study has been carried out on the splattering of impinging turbulent liquid jets on solid flat plates and curved surfaces (pipe sections and racks) commonly found in industrial installations. The results obtained cover flow rates of 11.9 1/s to 25.4 1/s (ie 17718 ≤ Re ≤ 37824 and 3150 ≤ We ≤ 14356) and nozzleto-target separation distances of 75 < L / d < 1000, for a nozzle of diameter, d = 1 mm. Splattering increases with L / d, Re (Reynolds number) and We (Weber number) until it reaches a plateau. At a given L /d, splattering is observed to have a stronger dependency on Re than We for this range of Re numbers. The results show that the parameters L /d and We should be treated as independent variables for the range of We and L /d used in the study. A wider range of applicability of the splattering model of Bhunia and Lienhard (1994) was observed. When the jet hit an initially wet plate a new fraction of much larger droplets are splattered out of the water film as compared to the case of the jet hitting the dry plate. Splattering was seen to increase with increasing surface curvature of the pipe section, with 0.17 m OD being the critical pipe size above which splattering of the impinging jet was similar to that for a flat plate. This was not the case with the jet hitting the pipe rack where no reasonable change in splattering was observed as compared to the jet hitting the flat plate. Keywords Impinging liquid jet, splattering, flat plate, pipe section, pipe rack, dimensionless nozzle-to-target separation, surface curvature and critical pipe size.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

412

(ICERD 08027) Anisotropic Behaviour of Deep Drawn Aluminium 1017Alloy using Macroscopic Tensile and Cupping Tests

(1)

S.A. Balogun(1), D.E.Esezobor (2) and S. O. Adeosun(3) Department of Metallurgical and Materials Engineering, University of Lagos, Akoka -Yaba, Lagos, Nigeria 23401 [email protected] (2) [email protected], (3) [email protected]

Abstract This paper presents a macro-mechanical approach for the determination of microstructural integrity of aluminium 1017 alloy. Tensile and cupping tests were carried out on cold rolled 1.2 mm and 1.6 mm samples. The paper examines the variation of plastic strain ratio, dislocation density, degree of deformation and ultimate tensile strength in relation to rolling orientation using macromechanically based stress and strain models. This approach is a tool for quick quality check on formability of blank material for cupping process and will assist in describing the efficiency of the intermediate processing of sheet annealing after the rolling performed prior to cupping. 1. Introduction The elasto-plastic behaviour of metallic materials is affected by various factors such as temperature, deformation and deformation rate as well as material parameters [1]. The behaviour of materials under deformation such as, grain growth, dislocation density and diffusion mechanisms is temperature dependent. After cold deformation of a metal or an intermetallic material, some of the energy involved in the deformation is stored as dislocations and point defects. This is often referred to as stored energy of cold work. During annealing, the number of point defects is largely reduced. The dislocations of opposite signs attract, and annihilate each other and the dislocations may rearrange themselves into lower energy configurations. These point and line defects are absorbed by grain boundaries migrating through the material; and reduction in the grain boundary area occurs [2]. The change from cube to a rolling texture implies a diametrical anisotropy behaviour, which can be noted in deep drawn cups. For cold rolled, Al-Mg materials after strain hardening and subsequent annealing the material undergoes recovery due to annihilation of dislocations and dislocation rearrangement leading to a drop in strength [3]. The texture introduced into a sheet by different processing routes affects its nonuniformity in properties. This includes variation in strength at different orientations of the sheet or forming behaviour which may produce ears during deep drawing [4]. Tensile tests provide information about strength, elongation and formability. Formability is usually determined by the value of the average plastic strain ratio, R, whose values are measured at 00, 450 and 90o to the rolling direction. Since the flow strength of the sheet in the thickness direction is difficult to measure, R can be used to compare strengths in the plane and thickness directions in a tension test. High R value is beneficial for deep drawing as it indicates a resistance to thinning of the sheet thickness. In the production of cans, for instance, highly cold rolled strip is used to meet the strength requirements. Thus a strong -fibre

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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rolling texture is always formed. Conversely, the formability of the blank depends on the previous rolling history of the blank material and its microstructural integrity. The mechanical properties of the sheet vary in different directions. Ears are formed due to uneven metal flow in different directions and this is directly related to planar anisotropy. Sheets with high normal anisotropy often have high planar anisotropy that leads to pronounced earing. Anisotropy is acquired during the thermo-mechanical processing of sheets due to varied material properties at different directions of the rolled sheet. Planar anisotropy in the sheet metal gives rise to ears in the drawn cup. One approach to avoid this problem is to suitably modify the initial blank shape and thereby produce a final cup shape that is ear-less. An experimental trial and error process to determine the best blank shape for making a defect free cup is very expensive and time consuming. Numerical simulation of tools may present an attractive and effective alternative [5]. The rearrangement and annihilation of the lattice defects result in the change of many physical properties. The measurement of these changes yields valuable information on the properties of defects. In a metal plastically deformed at low temperatures, large numbers of defects are generated. If this metal is subjected to gradual heat-treatment the defects are activated at different temperatures, and their mutual annihilation decreases the internal energy of the crystal. X-ray investigations have shown that re-crystallization begins at the same time as the rapid energy release. Naturally, the development of the re-crystallization process depends upon the magnitude of the previous deformation. With very large internal stresses, the thermodynamic instability of the internal stresses occurs at lower temperature. Stored energy increases as degree of deformation increases, while, temperature of re-crystallization decreases. Electron Microscopy has being used to characterize the morphology, elemental composition and crystal structure of materials and submicron scale. The characterization of real materials microstructure involves phase structure, stereology, crystallographic texture and substructure (e.g. point defects, dislocations, solid solution, ordering, stacking faults and twins, lattice strain/ local residual stress). A comprehensive description of microstructure, will involve a variety of sophisticated experimental techniques for measurement. Energy dispersive x-ray spectroscopy (EDS) in the SEM or TEM is widely used as the standard techniques for (semi-) quantitative elemental analysis and element mapping at a meso-scale. A new technique known as ACOM (automated crystal orientation measurement/mapping) in the quantitative characterization of microstructure of bulk crystalline materials has been achieved [6]. These techniques reveal charges in microstructure and inhomogeneous distributions of crystal texture by plastic deformation. These new techniques (SEM, TEM, X-Ray are highly sophisticated and expensive for use as routine quality check in the industry. These types of measurements involve tedious sample preparation. The need to have reliable method of routine quality check on profiles in the industry has brought about the development of an algorithm-based model. This paper presents this model and its use in the determination of substructure defects in the material. This paper presents the anisotropic behaviour of 1017 aluminium alloy in deep drawing operation. Dislocation density and degree of deformation which are micro properties of materials are deduced using macromechanically based stress and strain models [6], which agree with experimental stress-strain results obtained from tensile test.

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The determination of these parameters will assist in describing the efficiency of the intermediate processing of sheet annealing after the rolling performed prior to cupping. This could be a tool for quality control department. This verification will not require the tedious sample preparation encountered during microstructural investigation of aluminium alloy using sophisticated, and expensive and highly technical equipment such as TEM, SEM or X-ray. 2. Methodology Experimental Analysis Materials and test facilities for experimentation were provided by Aluminium Rolling Mills, Ota, Ogun State, Nigeria. Cold AA 1017 sheets that have been annealed were used for this study.

Test samples were made from 1.2 and 1.6 mm thickness of cold rolled sheet. The thickness and chemical composition of these sheets are shown in Table 1. Table1. Chemical Composition of Specimens Sheet Thickness, mm Al Fe Si Ca 1.2 99.38 0.319 0.093 0.131 1.6 99.01 0.512 0.226 0.044 Quality limit level: Fe≤ 0.4%, Cu ≤ 0.05, Si ≤ 0.23%.

Mg 0.002 0.002

Experimental tests were carried out through the following routes. Tensile Test Rectangular test pieces required for tensile test were cut from a circular blank sheet-using snip at various angles to the rolling direction. These were placed on a die with a cylindrical cavity and blanked by a manually operated machine. Two flat tensile pieces of the form shown in Figure 1 were prepared for each sheet thickness. The test sample was gripped between the ends of the tensometer-testing machine and axis of tension is along the axis of the test sample. A maximum test load of 5 KN was used during the experiment. Cupping Test The cupping test was conducted to determine the drawability of the sheets in accordance with ISO 1520:2006 (BS EN ISO 20482:2003 [7]. Two 60 mm diameter blank test pieces were gotten from each sheet using the blanking head of an Erichsen cupping machine (Model 142 – 20/40: Universal Steel Metal Test Machine). Blanking die and punch diameter was 62 mm and 33 mm respectively. The samples were geometrically marked at intervals of 150 to 900 from rolling direction. An E.P.140 lubricant was applied on the test pieces and on the punch head. Heights of the drawn cups were measured using Vernier Caliper. Theoretical analysis The derivations of model equations to describe the anisotropic plastic flow of the metal sheet in plane stress condition are detailed in Balogun et al [8]. The derived equations 1-3 are presented below True strain, d 1

d 

P[(1   ) 2  2 ( 2  Sin 2 )   2 ( 2  Sin 2 )] 2 d 3( )

(1)

1 2

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Plastic Strain Total Plastic Strain, å 1

 

K Pr 2  3 [ 23 ( 2 2  1)] 2

(2)

384 EI

Stress Model True Stress, 1

 

P  [(1   ) 2  2 ( 2  Sin 2 )   2 ( 2  Sin 2 )] 2

(3)

1

2 a ( ) 2

where, dë is the ratio of plastic strain increment to deviatoric stress= 0.001; è is the inclination of test sample to the rolling direction in radian; K is the dislocation density, a is the cross-sectional area of test piece; P is the punch force, E is the Young modulus of material, ã is the degree of deformation, õ is the Poisson ratio ≈ 0.36 (0.33 – 0.55), I is the moment of inertia of material; r is the forming tool parameter (punch corner radius) Dislocation Density The derived plastic strain relation (Eq. 2) is a function of dislocation density for an anisotropic material. This plastic strain is fitted into both the stress model and the empirical relation obtained from experimental data. The resultant stress obtained in both cases was compared to determine the dislocation density value. Stress-Strain relations Using equations 1-3 the obtained values of dislocation density and degree of deformation at different inclination to rolling direction obtained experimentally and theoretically were analyzed. Cup height (CH) relation The relation is expressed as D = √ (d2+4dH) (4) P =  S d t ((D/d)-c) (5) where, D is the blank diameter, d is the shell/punch diameter, t is the sheet thickness, S denotes tensile strength of sheet, c is a constant (0.6-0.7), H denotes the CH. The theoretical stress for deformation ó expressed as a function of S, D, d, and c [9] can be evaluated as ó = S (D-c d)/d (6) Combining equations 3 and 6 and substituting for D in terms of H, we have

H 

 0 .5 Pd  11 .04 S

2

2

2

2

2

2

 2(1   )   2  (1   )  Sin 2   Sin 2   

1/ 2

  

2

  cd   d 2 

4d

2



where, ä is D/3 Fitting a quadratic relation to the experimental data, we have (8) H 1  20.573  2.48 x  1.87 x 2 Thereafter, comparison of the theoretical and experimental data was done. Measurement of Anisotropy Plastic strain ratio (R) is given as the ratio of width to thickness strain i.e.

 wo / w  Rs  LnRs  Ln   ho / h 

(9)

where, w0 is initial width of sheet (12 mm); w is final width of sheet; h0 is initial thickness of sheet; h is final thickness of sheet;

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(7)

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Since thickness measurements are difficult to make with precision on thin sheets, the equation above can be written using the constancy-of – volume relationship. Thus, ln w0 w h w (10) R   h  (w  h i )  ln w0l0 wi l 

R

1nw0 w 1nwl w0l0 

(11)

where, lo is the initial gauge length (50 mm), l is the final gauge length The variation of width and gauge length with respect to rolling orientation for the sheets is shown in Table 2. The normal anisotropy Rm is determined using R 0  2 R 45 0  R 90 0 (12) Rm  0 4 While, the planar anisotropy ÄR, is determined using

 R 0  R90 0 R   0 2 

    R45 0   

(13)

Microstructural Analysis The as-received samples used for experimentation were prepared for micrographical examination through light grinding using silicon carbide paper. Polishing of the samples was done with alumina paste. A mixture of NaOH solution in water was used as the etchant. The microstructural integrity of the test samples was examined under a digital microscope with magnification of 100 micron. Table 2. Variation of sheet width and gauge length with respect to rolling orientation during tensile deformation Inclination to rolling direction (degree) 1.2 mm 1.6 mm

0 15 30 45 60 75 90

w 10.9 11.5 11.15 10.95 11.10 11.10 10.85

l 64.10 65.10 62.90 65.10 64.05 64.55 65.15

w 11.05 11.25 11.05 10.80 11.05 10.85 11.05

l 64.45 63.60 66.00 68.10 65.65 65.45 63.00

3. Results and Discussion Ultimate Tensile Stress (UTS) The obtained tensile test results are shown in figures 2 and 3. The UTS is highest in 1.2 mm thick sheet at the rolling direction (see Figure 3). This is probably due to the presence of high volume of both immobile and mobile dislocations (107 mm-2). However, at 900 both sheets show close values of mobile dislocation (104 mm-2). This indicates the presence of strong volume of immobile dislocations and the strengthening effect is not sufficiently complimented by the mobile dislocations. It is suggested that directions of mobile and immobile dislocations could influence their combined effect [10]. If aligned in the same direction, the strength tends to increase to attain equilibrium; otherwise, the strength will fall. In the 1.6 mm sheet, the UTS increased progressively from the rolling direction to 450 orientations.

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The presence of high volume of immobile dislocations in the cold rolled sheet will have a profound effect on the strength of the material. The existence of immobile dislocations may have been by the residual stresses obtained through improper annealing process. Although mobile dislocations can be readily annihilated during annealing, immobile dislocations require proper process control and implementation [10]. The precipitation of strong cube structure will assure complete annihilation of both forms of dislocations. The UTS of samples is high between 450 and 900 orientations, with the highest value occurring in 1.6 mm thick sheet. The high UTS values observed in 1.6 mm sample over that of 1.2 mm sheet is due to the presence of fine crystals of both á-aluminium and Al3Fe and reduction in texture and concentration of the Al12Fe3Si phase in the matrix. This may also account for the high resistance to thinning seen in 1.6 mm sample. The high intensity of work hardening arising from high degree of deformation especially at 900 orientations is enhanced by the texture of Al3Fe crystals in the á-aluminium matrix. Since the values of mobile dislocations in the samples remained the same in any direction considered, the difference in cup height is negligible. Cup Height (CH) The variation of CH with inclination is shown in Figure 4. Comparing theoretical data (from equation 4) with the quadratic empirical data obtained from experimental investigations, there is a close agreement beyond 45o and this relation tends to be closer towards 90o. The theoretical relation gives a slowly increasing CH with increasing inclination to the rolling direction. The variation of CH with inclination to the rolling direction is shown in Figures 4 and 5. From the results, the CH increases as the angle to the rolling direction increases from 45o to 90o despite an initial decrease in height from rolling direction towards 45o orientation. However, towards the 45o orientation, there is more resistance to thinning. This could be due to the formation of relatively strong (110) plane structure generating dislocation density of 104 mm-2 (see Table 3). There is also a close agreement in the CH when data are fitted into a quadratic relation (see Figure 4). The variations and low value of dislocation density is an indication of in- homogeneity and poor recovery in the annealed structure, which is higher in the rolling direction. The degree of deformation is lowest at 450 in 1.2 mm (1.35) and in 1.6 mm (1.00). Degree of deformation is however higher in 1.2 mm sheet both at rolling direction and 450 than that obtained in 1.6 mm sheet (see Table 3). The tensile strength of sheets increases in the rolling direction than in other directions. This is however pronounced in 1.2 mm, which tallies with the high degree of deformation observed in thin sheet (see Figure 2 and Table 3). At 450 the sheets experience low work hardening as shown by the resulting degree of deformation (1.35 for 1.2 mm and 1.00 for 1.6 mm). At 900 the work hardening is high as can be seen from the value of the degree of deformation in Table 3. Table 3. Variation of dislocation density (K) and degree of deformation (ã) with inclination to direction of rolling in aluminium 1017 alloy sheets. 1.2 mm Cold rolled 1.6 mm Cold rolled 0 o o 0 Inclination to rolling direction 0 45 90 0 45o 90o -2 7 4 4 7 4 Dislocation density (K), mm 10 10 10 10 10 104 Degree of deformation (ã) 1.90 1.35 2.55 1.70 1.00 3.94 Plastic Strain Ratio (R) Computations of the values of normal and planar anisotropy of aluminium 1017 alloy equations 12 and 13 are shown in Table 4. The results indicate the behaviours of R are sinusoidal and have peaks at 00, 450 and 90o except at 800 for 1.6 mm thickness (see Figure 6). The results indicate the variation from the rolling direction of anisotropic behaviour of plastic flow towards the direction normal to rolling direction.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria Table 4 Normal and planar anisotropy of aluminium 1017 alloy Sheet plastic characteristics 1.2 mm Normal anisotropy, Rm 0.5755 Planar anisotropy, ÄR 0.0890

418

1.6 m 0.5170 0.000

Relatively the R value at 1.2 mm thickness is higher (~0.63) than that of 1.6 mm sheet (0.47) in the rolling direction. And, at 90o to the rolling orientation, the values are ~0.61 and ~ 0.55 respectively. At 45o, R-values for 1.2 mm and 1.6 mm sheets are 0.53 and 0.52 respectively. Nevertheless, resistance to thinning is nearly the same. Microstructural Analysis Figure 7 shows a micrograph of 1.2 mm sheet thickness. The matrix contains high spherical precipitates of coarse almost rounded discrete cubic Al12Fe3Si crystals uniformly dispersed across the entire á-aluminium matrix. On the other hand, in Figure 8 (1.6 mm), very fine crystal of both á-aluminium and Al3 Fe exist together similar to that in Figure 7. There is reduction in size and intensity of Al12Fe3Si crystals compared to that obtained in 1.2 mm thickness. Normal and planar anisotropy values support this assertion (see Table 4) as the distributions of phases remain random. The resistance to thinning is relatively high at 900. This promotes substantially high CH compared to other directions. The theoretical relation predicts a gradual increase in height from rolling direction to 900 orientations. At lower degree of inclination where there is a marked difference in CH between experiment and theory, the inhomogeneity in microstructure could account for this phenomenon. Moreover, this result corresponds to the observation previously made with AA 6013 sheets by Oritz et al [11]. Indeed, in the studied alloy, the presence of Al12Fe3Si crystals in the aluminium matrix is responsible for the inhomogeneity in structure. This accounts the planar anisotropic behaviour observed in 1.2 mm sample (see Table 4). The effect of this defect is the attendant high value of degree of deformation in the rolling and 450 orientations. The values of degree of deformation and dislocation density indicate the level of microstructural defects which are usually determined experimentally through SEM, TEM or other complicated examinations [11, 12]. 4. Conclusion The formability of deep drawn metals is dependent on its previous deformation and thermal history as well as its microstructural integrity. Every cold rolled sheet has to be annealed after deformation prior to drawing at 480oC for 5 hours and step down to 420oC for 2 hours. Improper annealing will affect the material formability. The cause of this is inhomogeneity in microstructure. Determination of dislocation density and degree of deformation can be used to analyze the effectiveness of annealing process and subsequent deep drawability. These parameters are normally determined using sophisticated and expensive facilities such as TEM, SEM and X-ray. This study has shown that results of macromechanical test when fitted into stress relation can be used to obtain these parameters. Thus, qualitative evaluation of the annealing process and the suitability of sheets for cupping can be carried out at very low cost and with common facilities. 5. Reference 1. M. Oktay Al Niak and Fevzi Bedir. Changes of Grain sizes and Flow Stresses of AA2014 and AA6063 Aluminium Alloys at High Temperatures in various Strain Rates. Turkish J Eng Environ Sci 2003: 27, p.59-64 2. Baker, I. Recovery, Recrystallization and Grain Growth in Ordered Alloys. Intermetallics 2000: 8, p.1183-1196.

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3. Tikhovskiy, D. Raabe, F. Roters. Simulation of Earing during Deep Drawing of an Al–3% Mg Alloy (AA 5754) Using a Texture Component Crystal Plasticity FEM. J. Mater Process. Technol. 183, (2-3), 23 March 2007, p 169-175 4. Banabic D, Wagner S. Anisotropic Behavior of Aluminum Alloy Sheets. Aluminum 2002: 78 (10), p. 926-930. 5. Vija Pegade, Young Chun, Sridhar Santhanam. An Algorithm for Determining the Optimal Blank Shape for the Deep Drawing of Aluminum Cups. J. Mater Process. Technol 2002: 125-126) p. 743-750. 6. Adams, B.L., Wright, S.T., Kunze K. (1993): Metallurgical Transactions 1993: 24 A p. 819 7 BS EN ISO 20482:2003. Metallic Materials. Sheet and Strip. Erichsen Cupping Test. British Standard/EN/International Organization for Standardization. 08-Sep-2003. 16 p 8. Balogun, S.A., Adeosun, S.O., Esezobor, D.E. Stress Variation in Deep Drawn 1017 aluminum alloy. .J Mater Eng Perform 2007 16 (6), p.766 – 774 9. Wick, C., Benedict, J.T. Veilleux, R.E. Tool and Manufacturing Engineers. Handbook Volume II: Forming. Society of Manufacturing Engineers, Michigan, 4th Edition. 1984. P. 4.42 – 4.45 10. Balogun, S.A., Esezobor, D.E., Adeosun, S.O. Effects of Deformation Processing on the Mechanical Properties of Aluminium alloy 6063. J. Metall Mater Trans. A, 2007, 38, (7), p 1570-1574. 11. A.L. Oritz and L. Shaw. X-ray diffraction analysis of a severely plastically deformed aluminium alloys. Acta Materialia. 2004: 52, Issue 8, p. 2185 – 2197 12. R. Sztwiertnia, M. Bieda, G. Sawina. Determination of crystalline orientations using TEM. Examples of measurements. Archives of metallurgy and materials. 2006: 51 (1)

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria 100

12

t

25

50

25

Figure1.Tensile test piece sample (dimensions in mm)

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420

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Conversion Radians 0 0.2618 0.7854 1.042 1.3090 1.571

Degrees 0 30 45 60 75 90

C

B

B A

B

100

100

Figure 7 Micrograph of 1.2 mm AA 1017 sample

Figure 8 Micrograph of 1.6 mm AA 1017 sample.

(A- á aluminium, B-Al3 Fe, C- Al12Fe3Si)

(A- á aluminium, B-Al3 Fe, C- Al12Fe3Si)

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(ICERD 08084) Simulation of Load during Rod Rolling Of HC SS316 at Low Strain Rate P. O. Aiyedun(1), O. S. Igbudu(2), B.O. Bolaji(3) (1, 3) Department of Mechanical Engineering,University of Agriculture, P.M.B. 2240, Abeokuta, Nigeria. e-mail: [email protected] (2)

Department of Mechanical Engineering, Ambrose Alli University, Ekpoma

Abstract: In this work, rolling loads of HCSS316 for seventeen sequential passes for the reduction of a 125 x 125 mm2 billet to a 16 mm diameter rod at four different starting mean temperatures of 9880C, 10940C, 10950C and 11910C and at different strain rates of 0.4s-1, 0.8s-1, 1.2 s-1 and 1.6 s-1 respectively, were simulated using the “Phantom Roll” method for Carbon-Manganese steel. In general, it was observed that load value increased as starting temperature decreases and for each set of starting temperatures, the load value increases with temperature. In all cases, the load values for grooved rolls were higher than those for flat rolls. Keywords: Rod rolling, Load, Strain rate, Temperature. 1 Introduction Rolling is one of the most important metal working processes [1] whereby metals are plastically deformed. It is a direct compressive type of deformation in which applied compressive stress induces two compressive stresses, which are on mutually perpendicular planes. Forging and extrusion also fall under this type of deformation process. Rolling is used to reduce the thickness of the work-piece [2]. It could be carried out either cold or hot. Cold rolling is carried out at temperature below the recrystallisation temperature of the metal, while hot rolling is carried out at temperature above the recrystallision temperature. Cold rolling increases the dislocation density and alters the shape, but not the average size of the metal grain. The process generally increases the strength and decreases the ductility of the metal. On the other hand, hot rolling significantly alters the microstructure of the metal such as homogeneity of texture, the size and shape of grains and the concentration of point and line defects (dislocations). Two methods of rolling are distinguished-flat rolling and form rolling. Flat rolling is a process in which a work-piece of constant thickness enters a set of rolls and exit as a product with different constant thickness using flat rolls. Form rolling or shape rolling is a rolling method for products such as I-beam, channels, railroad tracts and large diameter pipes and rods using grooved rolls [2]. For rod rolling, which is the focus of this work, grooved rolls are used. Warm working is deformation carried out at any temperature and strain rate that some amount of strain hardening is always evident [3, 4] or the simultaneous occurrence of deformation and recovery process whereby metals are deformed in their plastic condition by successive passes carried out at temperature above recrystallisation using a rolling mill [5]. The simultaneous deformation and recrystallisation, apart from saving of energy, also results in considerable speeding-up of the process. Rod rolling as a hot working process is the basis of this work using HC SS316 at low strain rates. In general, rolling is a more economical method of deformation than forging if metal is required in long lengths of uniform cross-section [1]. Computer simulation models which predict temperature, load, torque and micro structural changes are very powerful tools as it would be difficult, if not impossible, to obtain these parameters from a few surface measurements. The knowledge of accurate temperature makes it possible to evaluate load during rolling and micro structural changes. A lot of computer simulation models have been reported in the past in flat rolling, pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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mainly for load calculations to design mills at the maximum energy consumption [6]. Different assumptions were made for simplicity and the finite difference method was most commonly employed. Kawai [6] developed a computer simulation model, which predicts temperature and micro structural changes for rod rolling of mild steel and medium carbon steel. Assumptions made were:  Sections of the material are round;  One dimensional heat flow within the material. Heat flows from the center to the surface;  Heat gain due to deformation is equally distributed to each element and for every time interval during rolling;  Heat loss is caused by radiation and convection during air-cooling and by conduction during rolling;  A ‘phantom roll’ method was used. For the first above, a geometric factor was introduced to modify the round sections to the real sections. The ‘phantom roll’ method makes it possible to ignore the temperature calculation in the roll while reasonable accuracy is maintained. Also, it makes it possible to save the computer calculation in the roll by assuming a parabolic temperature distribution. This method saves more of computer time and memory [7]. Oseghale [7] in his work expanded the ‘phantom roll’ method to take care of load and torque calculations by neglecting the effect of roll flattening or deformation in the near surface region of the rolls. He also, in addition to the assumptions made by Kawai, assumed that a two dimensional deformation of metal (carbon manganese steel) during reduction. Aiyedun [8] in his work made a comparison between the theoretical load and torque to that obtained experimentally using HC SS316 steel slab at low reduction and low strain rate (0.08-1.5s-1) by hot rolling the steel at different temperature using the modified Leduc’s programme which uses the Sim’s sticking friction approach. He observed that there was excessive load and torque in comparison with values obtained by normal rolling practice at low strain rates and low reduction for flat rolling. The difference was observed to be influenced by temperature, micro structural changes, precipitation strengthening and composition. The precipitation strengthening was more pronounced at low strain rates [9]. In this work, attempt has been made to roll-up all above three discussed models into one ball so as to simplify and integrate the various features linking them together for the evaluation of load during rod rolling of HC SS316 at low strain rates. Accordingly, an assumption similar, to that of Oseghale [7], was adapted. Also, a continuous rolling mill was used in view of the shortcomings of a two-high mill. 2. 2.1

Mathematical Model Rolling Load

In the evaluation of load, Ekelund’s method used as input data temperature, reduction and velocity. It is as given below [7]. The rolling load, in kg is P = ApKw

(1) 2

where, Ap, is the projected area, mm

Kw, is the mean roll pressure, calculated under actual rolling conditions, kg/mm2 Ap = bmL

(2)

bm = (bo + b1)/2

(3)

where L = projected contact length bm = average stock width bo = breadth before entry b1 = breadth after exit pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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2.2 Evaluation of Contact Area (Ap) Between the Rolled Material and the Rolls The mean width of the rolled strip over zone of deformation (bm) is determined using equation (3). However, if the edge of the rolled strip over the zone of deformation is approximated not by a circle but by an arc of a parabola then, equation (4) is used.

bm  bo 

2 3

b1  bo 

(4)

bm = bo + 2/3(b1 + bo) The quantity L in equation 2 is found from the relation given below if the angle of contact is known.

L  AC  rh

(5)

For rolling in non-rectangular section rolls, and taking h equal to the mean linear reduction over the width of the section, that is,

h  -

Qo Q1  bo b1

(6)

for a Rhombus rolled from Rhombus, h = (0.55 to 0.56) (ho – h1)

(7)

for Oval rolled from a Square, h = ho – 0.7h1 (for shallow oval)

(8)

h = ho – 0.85h1

(9)

(for round oval)

-

for a Square rolled from an Oval, h = (0.65 to 0.7)ho - (0.55 to 0.6)h1 (10)

-

for a Circle rolled from an Oval, h = 0.85ho – 0.79h1

(11)

where, ho – dept of cross-section of strip before the pass h1 – dept of cross-section of strip after the pass. 2.3

Evaluation of Zener-Hollomon Parameter (Z)

The Zener-Hollomon parameter is given as [10], Z = exp (Q/RT)

(12)

The strain rate is obtained using equation 13

  ln  

 1 L   ln d  E 0 

(13)

the approximate mean rolling strain rate is given by



3.5

= [1.08V/(Rh)1/2] [(h)1/2/h1h2]0.25 [ln(h1/h2)]0.45 (14) Simulation of the Model pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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In the simulation of the model, conditions and input data similar to those of Oseghale [7] were assumed for this work. A 125125mm2 stainless steel (HCSS 316) square billet was used as the starting material for rolling to a 16mm diameter rod using 17 sequential passes. Assumptions made were:  Water cooling to the material such as de-scalar and roll cooling system was neglected;  The air cooling condition was taken to be the same as the laboratory, although, a lower cooling rate is because of the obstruction of radiation by the trough between mill stands;  The roll radii for flat and grooved roll were taken to be 140mm and 254mm respectively;  The value of the activation energy of deformation for HC SS 316 was taken to be 460KJ/mol, [11];  The friction factor or coefficient of friction between roll and stock was assumed to be 0.25 based on the experimental result of El-Kalay and Sparling who concluded that coefficient of friction varied between 0.23 and 0.38 [11]

3. Results and Discussion The simulation was carried out starting with four different mean temperatures of 9880C, 1094 0C, 1095 0C and 1191 0C and starting strain rates of 0.4 s-1, 0.8 s-1, 1.2 s-1 and 1.6 s-1, respectively for seventeen sequential passes in a continuous rolling mill. The input data were based on those of Oseghale [7]. Figures (1 to 8) show the plots of load against temperature. For both flat rolls and grooved rolls, the points were fitted with curves for all starting temperatures. As shown in these figures, it was observed that for grooved rolls, load values were larger than for flat rolls; this translates into more power dissipation with grooved rolls. The higher values encountered could probably be due to:  Higher value of projected contact area between roll and stock for grooved rolls;  Friction effect due to the side wall of grooved rolls as a result of higher value of the projected area of contact. The plot of load against log10(Z) is shown in figure (9). The points were fitted with straight lines for both grooved and flat rolls. An inverse relationship exists between log10(Z) and load.

30

988 degree Celcius 1094 degree Celcius 1095 degree Celcius 1191 degree Celcius

Load (MN)

25 20 15 10 5 0 850 900 950 1000 1050 1100 1150 1200

Temperature (0C)

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Fig. 1: Plot of load versus temperature for rolling using flat rolls at initial starting strain rate of 0.4s-1 for four mean temperatures 988 degree Celcius 1094 degree Celcius 1095 degree Celcius 1191 degree Celcius 25

Load (M N)

20 15 10 5 0 850 900 950 1000 1050 1100 1150 1200

Temperature (0C) Fig. 2: Plot of load versus temperature for rolling using grooved rolls at initial starting strain rate of 0.4s-1 for four mean temperatures 988 degree Celcius 1094 degree Celcius 1095 degree Celcius 1191 degree Celcius 24 20

Load (M N)

16 12 8 4 0 850 900 950 1000 1050 1100 1150 1200

Temperature (0C)

Fig. 3: Plot of load versus temperature for rolling using flat rolls at initial starting strain rate of 0.8s-1 for four mean temperatures

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16

427

988 degree Celcius 1094 degree Celcius 1095 degree Celcius 1191 degree Celcius

14

L o a d (M N )

12 10 8 6 4 2 0 850 900 950 1000 1050 1100 1150 1200

Temperature (0C) Fig. 4: Plot of load versus temperature for rolling using grooved rolls at initial starting strain rate of 0.8s-1 for four mean temperatures

988 degree Celcius 1094 degree Celcius 1095 degree Celcius 18

1191 degree Celcius

16

Load (M N)

14 12 10 8 6 4 2 0 850 900 950 1000 1050 1100 1150 1200

Temperature (0C)

Fig. 5: Plot of load versus temperature for rolling using flat rolls at initial starting strain rate of 1.2s-1 for four mean temperatures

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428

988 degree Celcius 1094 degree Celcius 1095 degree Celcius 1191 degree Celcius

16 14

L o ad (M N )

12 10 8 6 4 2 0 850

900

950 1000 1050 1100 1150 1200 Tem perature (0C)

Fig. 6: Plot of load versus temperature for rolling using grooved rolls at initial starting strain rate of 1.2s-1 for four mean temperatures

988 degree Celcius 1094 degree Celcius

16

1095 degree Celcius 1191 degree Celcius

L o ad (M N )

14 12 10 8 6 4 2 0 850 900 950 1000 1050 1100 1150 1200

Temperature (0C) Fig. 7: Plot of load versus temperature for rolling using flat rolls at initial starting strain rate of 1.6s-1 for four mean temperatures

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988 degree Celcius 1094 degree Celcius 1095 degree Celcius 1191 degree Celcius

18 16

Load (M N)

14 12 10 8 6 4 2 0 850 900 950 1000 1050 1100 1150 1200

Temperature (0C)

Fig. 8: Plot of load versus temperature for rolling using grooved rolls at initial starting strain rate of 1.6s-1 for four mean temperatures

Flat rolls at 1095 degree Celcius Grooved rolls at 1095 degree Celcius Flat rolls at 1191 degree Celcius Grooved rolls at 1191 degree Celcius 25

Load (MN)

20 15 10 5 0 18

20

22

24

26

28

Log10(Z)

Fig. 9: Plot of load versus log10(Z) for seventeen passes for starting temperatures of 10950C and 11910C, and strain of 0.8s-1 using flat and grooved rolls The plot of load against strain rate for flat rolls is shown in figure (10). The figure shows a gradually decreasing load as strain rate increases; this also applies to grooved rolls. This indicates an inverse relation between strain rate and load.

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1095 degree Celcius

25

1191 degree Celcius

Load (MN)

20

15

10

5

0 0

20

40

60

80

100

Strain rate (s-1)

Fig. 10: Plot of load versus strain rate for rolling in flat rolls at starting temperatures of 10950C and 11910C 4. Conclusion Load plays a very significant roll during rolling operation. Therefore, there is the need to minimize them so as to reduce both cost and weight, which ultimately translates into low energy dissipation and consumption. It was observed that: 1. Increasing strain rate and temperature lead to a decrease in load values; 2. Larger contact area between roll and stock and additional frictional effect due to side walls of roll lead to increased load requirements for grooved rolls when compared to flat roll; 3. In view of 2 above, rolling in grooved rolls requires more power than for flat rolls. 5. References [1] Antonio, a. G. and Renato, R. V. (1996). The Effect of Finishing Temperature and Cooling Rate on the Microstructure and Mechanical Properties of As-hot Rolled Dual Phase Steel. Antonio Augusto Gorni home page, http://www.Geocities.com. [2] Schaffer P J, Sexana A, Antolovich D. S, Sanders T. H. Warner B. S, “Science and Design of Engineering Materials” 2nd edition, McGraw-Hill Company Inc., 1999, pp. 679-680. [3] Venkadesan S., Sivaprasad P. Venugopal S., Seetharaman V. “Tensile Deformation Behaviour of Warm-Rolled Type 316 Austenitic Stainless Steel” Journal of Mechanical Working Technology, vol. 12 (1986) p. 351. [4] Rollason E.C, “Metallurgy for Engineers” 4th edition, Edward Anorld, 1992. [5] Qamark H., Buckley G. W and Lewis M, “Computer Programmed Speed Roll-Torque Data Calculation”, Journal of Iron and Steel International, vol. 53, No 1, February, 1980, pp. 29-37. [6] Kawai R., “Simulation of Rod Rolling of Carbon-Manganese Steel”, M.Phil. Thesis, Department of Metallurgy, University of Sheffield, 1985. [7] Oseghale L. E, “Simulation of Load and Torque During Rod Rolling Using the ‘Phanthom Roll’ Method”, M.Sc. Thesis, Department of Mechanical Engineering, Univesity of Ibadan, 1998. [8] Aiyedun, P.O. (1984). A study of loads and torque for light reduction in hot flat rolling at low strain rates. Ph.D. Thesis, University of Sheffield, UK. [9] Honey Combe R. W. K, “The Plastic Deformation of Metals”, 2nd edition, Anorld, 1983. [10] Alamu, O. J. and Durowoju, M. O. (2003). Evaluation of Zener – Hollomon Parameter Variation with Pass Reduction in Hot Steel Rolling. International Journal of Environmental Issues, 1 (1): 148 – 159. [11] Sparling, L. G. M. (1983). “The Evaluation of Load and Torque in Hot Flat Rolling from Slipline Field” Proceedings, Institution of Mechanical Engineers. Vol.197A pp. 277. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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(ICERD 08085) ROLLING TEMPERATURE FOR STEEL HOT FLAT ROLLED AT LOW STRAIN RATES P. O. Aiyedun1, S. A. Aliu2 Department of Mechanical Engineering 1 University of Agriculture, PMB 2240, Abeokuta, Ogun State, Nigeria 1 e-mail: [email protected] [+234-802 316 2184: +234-703 887 8020] 2 University of Benin, Benin City, Nigeria Abstract Different methods of obtaining averages have been used to determine mean rolling temperatures from measured temperatures of various specimens during roll contact in hot flat rolling. The obtained mean rolling temperatures were used in turn in hot rolling simulation programs based on Sims, and Bland and Ford’s theories for calculating rolling loads and torque during hot flat rolling of steels at low strain rates (0.08 – 1.5 s-1). The hot rolling Bland and Ford’s (HRBF) Theory and Sim’s Theory gave similar results when any of the averaging methods of temperature is used to calculate rolling load and torque at high strain rates (1.5 –500s-1). However at low strain rates HRBF gave closer approximations to experimental results. Comparing the results with experimental values, the harmonic mean was found to give the best mean rolling temperature for hot flat rolling simulation at low strain rates compared to geometric mean, arithmetic mean and root mean square. Keywords: Hot flat rolling, Temperature, Load, Torque, Strain rate.

1.

INTRODUCTION Simple rolling theories such as Sims, and Bland and Ford, were used without difficulty for industrial hot flat rolling operations in the strain rate range of 1.5s-1 to 500s-1. However with low strain rates (0.01 – 1.5s-1) measured loads and torques were found to be excessive compared with calculated values [1-3]. The strength of a material is dependent on its microstructure and the condition during testing of which temperature and strain rate are very important [4]. Research has shown that the structure of material is equally very much dependent on temperature. Loads and torque are dependent on yield stresses and hence on temperature during hot rolling [3,5]. It has been widely reported that temperature changes continuously as a result of heat losses to the environment, to the rolls and due to heat generated by deformation of the metal during hot rolling. At low strain rates, changes in contact times are manifested in pronounced temperature changes. This led to the conclusion that temperature effects are the most important factors when hot rolling at low strain rates [1-3,6]. It therefore becomes important that appropriate mean rolling temperature be determined during hot flat rolling simulation at low strain rates.

2.

METHODOLOGY Rolling Theories (a) Sim’s Theory For Hot Rolling

For wide strip rolling the specific roll load, P and torque, T are estimated from equations (1) and (2):

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria N

P



S



Rd 

0

 S



Rd

(1)

N

/



 N

T  2 R0 R k   0 where -



S  d  k

 S  d  (2)  k N  



k

-

angle of entry (i.e. maximum value of ), radians instantaneous yield stress, N/mm2



-

angle subtended by a point on roll



432

surface w. r. t line joining roll centres, radians  N

-

1

Neutral angle, radians

R -

deformed roll radius, mm

R0 -

undeformed roll radius, mm

s

normal roll pressure N/mm2

-

These equations are based on Orowan’s result of compression of plastic slab between rough inclined plates, Von Karman equation and a number of assumptions due to Sims [1-3,7] (b) Bland and Ford’s Theory This is basically, a theory for cold rolling when sliding takes place throughout the arc of contact but found to be applicable to a hot rolling situation where sliding exists throughout the roll gap. This is the situation for hot rolling of HCSS 316 at 900oC – 1200oC; reductions of 0 – 15%; strain rates of 0.07 – 1.5s-1 and geometrical factor (R1/h2) of 4.0 – 20.00 [1-4]. Roll load and torque, are respectively obtained from:   N     / P  R  S d  S d  (3)  0  N







T  2 R0 R

/

 Sd

(4)

0

Based upon an earlier program called “Roll friction’ by Sparling and used for estimating the co-efficient of friction for a mixed sliding-sticking situation in hot flat rolling, a new program called Hot Rolling Bland and Ford, “HRBF” was developed to calculate mean yield stress during rolling and these were used to calculate rolling load and torque at low strain rates under sliding condition [1-3]. Influence of other Factors From the literature, factors such as yield stress, strain rate, rolling temperature, friction state, composition and micro-structural changes have been reported to have important effect on rolling load and torque [1-4, 8-

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9]. To relate microstructure, temperature and strain rate effect on material strength, Zener and Holloman (1944) [10] proposed that:

. Q    f z    f   exp RT  

(5)

where; Q

-

activation energy for deformation

R

-

gas constant

T

-

absolute temperature

Z

-

Zener-Hollomon parameter.

Mean Rolling Temperature Estimation Four methods have been used to obtain mean rolling temperature [11-13,14]. For n number of measured temperatures the arithmetic mean, geometric mean, harmonic mean and the root mean square are given by equations (6), (7), (8) and (9) respectively. 

x

1 n  xi n i 1

(6)

GM  n xi

(7)

1 1 n 1   HM n i 1 xi n

x

(8)

2

i

RMS 

i 1

n

(9)

where xi is measured temperature. Equations (6-9) were used to obtain mean rolling temperatures, which were subsequently used in Sims theory and HRBF to simulate hot flat rolling load and torque at low and high strain rates. Experimental The temperature of rolling specimen during hot rolling was measured at different times during roll contact using an embedded 1.5mm diameter “pyrotenax” inconel sheathed mineral insulated chromel alumel thermocouple. Temperature measurements were obtained for eight specimens each on mill A (H50 - H57) and mill B (P58-P65) of different roll diameters.

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To validate the hot flat rolling simulation, preliminary metallographic, hot torsion tests, and hot rolling experiments were performed on the as-received wrought AISI316 in the temperature range (600–1200)oC and strain rate range of (0.0036 – 1.4)s-1. The wrought material was High Carbon Stainless Steel; ASME SA-240 from Heat 38256-2C, product of G. O. Carlson Inc., P.A., U.S.A. It was cut into slabs of small sizes and hot rolled. The hot rolling experiments were performed on the two laboratory mills; a 1000kN, 2-high, single stand, reversible mill with rolls of 254.0mm diameter by 266.0mm barrel length (mill A) and 50T (498kN) capacity, 2-high reversible, Hille 50T rolling mill with rolls of diameter 139.7mm (mill B). Simulation of the Model Computer programs based on the two theories and the four averaging methods were developed in FORTRAN 77. The required input data were rolling speed, furnace temperature, initial and final thickness of the specimen, roll radius, rolling speed, roll contact time, corresponding temperatures, frictional rolling reduction and specimen width. The output of the programs includes mean temperature, yield stresses, rolling load and torque for the sixteen specimen investigated.

3.

RESULTS AND DISCUSSION

By estimating the ratio of experimental rolling load to calculated rolling load from the output of the computer program (Pex/Pcal), it was observed that the use of the harmonic mean (HM) gave the least average Pex/Pcal for the rolling theories investigated compared to what was obtained using geometric mean (GM), arithmetic mean (AR) and root mean square (RMS). This is evident from Fig. 1-4. Similar results were obtained for Gex/Gcal, evident from Fig.5-6. It was also observed that the use of root mean square (RMS) gave the highest Pex/Pcal values. Since low values of Pex/Pcal is an indication of closeness of calculated results to experimental measurements, it is implied that harmonic mean (HM) yield the best mean rolling temperature. For the rolling theories, it was also observed from Fig. 1-4, that HRBF gave lowest Pexp/Pcal (1.03-1.06) at low strain rates (0.01-1.5s-1) for harmonic, geometric, arithmetic and root mean square averaging methods compared to Sims theory, which gave Pexp/Pcal of 1.09-1.12. However, at high strain rates (>1.5s-1), HRBF theory gave higher Pexp/Pcal value (1.165  0.075) compared to Sims theory (1.12  0.062) for all the four averaging methods investigated. This implies that HRBF predicts rolling load closer to experimental values at low strain rates than at high strain rates irrespective of the averaging method employed. This is consistent with earlier reports in the literature [1-2, 8-9]. Similarly, Fig. 5 and 6 revealed the same observation for rolling torque estimation. From Fig. 5 and 6, for total strain rate range of 0.01-500s-1, (Gexp/Gcal)ave for Sims was 1.24,1.25,1.25 and 1.26 while that of HRBF was 1.30,1.31,1.32 and 1.32 for harmonic, geometric, arithmetic and root mean square average rolling temperatures respectively. It is also evident that Sims theory gives closer approximations to experimental measurement at high strain rates than low strain rates. Possible explanation for this have also been given in the literature [1-4] It is generally observed (from Fig.1-4 and Fig. 5-6) that ratio of experimental torque to calculated torque is higher than the ratio for load. This is a further confirmation of the earlier findings that the effect of changes in flow stress occasioned by temperature changes is more pronounced for torque than for load calculation [14].

4. CONCLUSION It can be concluded from this study that the harmonic mean gave the best mean rolling temperature for hot flat rolling of steels at low strain rates (0.01-1.5)s-1 than the geometric mean, arithmetic mean and the root mean square. The HRBF method of load and torque estimation gave results with closer approximation to pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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experimental measurements at low strain rates better than Sims method. Also, the effect of changes in flow stress occasioned by temperature changes is more pronounced for torque than for load calculation. 5.

REFERENCES

[1] Aiyedun, P. O. “A Study of Loads and Torques for Light Reduction in Hot Flat Rolling”, Ph. D. Thesis, University of Sheffield. (1984). [2] Aiyedun, P. O. “Hot Flat Rolling Simulation by Use of the Bland and Ford’s Cold Rolling Theory for HCSS316 at Low Reduction and Low Strain Rates”, Proc, Int. AMSE Conf., 3 (1): 14 – 36. (1986) [3] Aiyedun, P. O., Sparling, L. G. M. and Sellars, C. M., “Temperature Changes in Hot Flat Rolling of Steels at Low Strain Rates and Low Reduction.”, Pro. Instn. Mech. Engrs. Vol 211, Part B, pp. 261-284, (1997). [4] Aiyedun, P. O. and Sellars, C. M. “Effects of Fine Precipitate on the Strength of High Carbon SS316 Hot Flat Rolled at Low Reductions and Low Strain Rates” NSE Technical Transactions 33 (4): 67 – 100. (1998). [5] Leduc, L. PhD Thesis, Sheffield University, (1980). [6] Sellars, C. M. “Computer modelling of hot working processes.”, In Perspectives in Metallurgical Developments, Centenary Conference Proceedings, Department of Metallurgy, University of Sheffield, pp 202-217, (1984). [7] Afonja, A. A. and Sansome, D. H. “A Theoretical Analysis of the Sandwich Rolling Process” Int. J. Mech. Sci., 15 (1): 1 – 14, (1973). [8] Alamu, O. J. and Aiyedun, P. O. “A Comparison of Temperature Gradient in Hot Rolling at Low and High Strain Rates” J. Sci. Engr.Tech., 10 (1):4644 – 4654, (2003). [9] Alamu, O.J., Aiyedun, P.O., Kareem, A. and Waheed, M.A. “Effect of AISI 316 Stainless Steel Geometry on Temperature Distribution During Hot Rolling at High Reduction” in Advanced Materials Research -Advances in Materials and System Technologies, Vols. 18-19, pp. 195-200, Trans Tech Publications Ltd, Switzerland, (2007). [10] Zener, C. and Holloman, J.H. “Effect of strain rate upon plastic flow of steel. J. Appl. Physics, vol. 15 pp22 – 32, (1944). [11] Connor, L. R. and Morrell, A. J. H. Statistics in Theory and Practice, Pitman Publishing Limited, 7th ed., (1977). [12] Frank, W.S., Robert, E.H., and Carl, H.W “Introduction to Thermal Sciences, Thermodynamics, Fluid Dynamics, and Heat Transfer”. John Wiley and Sons 2nd ed. (1993). [13] Aliu, S. A. “Estimation of Mean Rolling Temperature during Roll Contact for Correct Flow Stress for Hot Flat Rolling Steels at Low Strain Rates.”, M.Sc Thesis, University of Ibadan, (2002).

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(ICERD08160) SPECIFICS OF FORMATION OF SEGMENTED CHIPS DURING TURNING OF TITANIUM AND ITS ALLOYS

O.O. AWOPETU, A.A. ADEROBA, A.O. DAHUNSI Mechanical Engineering Department, School of Engineering and Engineering Technology. Federal University of Technology, P.M.B. 704 Akure, Ondo State. Nigeria. Tel: 0803-604-9531. e-mail: [email protected], [email protected], [email protected] ABSTRACT: In this work, three types of commonly used work-pieces, namely, mild steel, stainless steel and titanium as well as their alloys were machined on the lathe machine under the same cutting conditions. During the cutting operations, chip roots were obtained with the help of a quick stop mechanism. These chip roots, obtained from the different work-pieces, were studied to understand the process of chip formation. The study revealed that not only is the chip formation process in titanium and its alloys not stable, it also differs from that of other two work-piece materials. Key words: segmented chips, cyclic chips, turning, titanium, thermal conductivity, tool wear. Introduction Titanium and its alloys are gradually finding their ways into the manufacturing sphere most especially in the aviation and the defence industries. This, of course, is not unconnected with their extremely favourable physical, chemical and mechanical properties and most especially the combination of the lightness in weight and high strength of titanium and its alloys compared to other metals [1]. Titanium and its alloys are also inert in most known media. Machining titanium and its alloys is however, always classified under the difficult-to-machine work-piece materials. This is connected with the fact that turning of titanium and titanium alloys is always characterized by high temperatures in the cutting zones at very close distances to the cutting edge, as a result of the low thermal conductivity of titanium and its alloys, resulting in low cutting speeds, reduced tool life as well as the formation of segmented or cyclic chips. These chips are problematic and unfavourable during production as they could even aid intensive tool wear and are difficult to evacuate. Although, these chips look like most others, the mechanism of their formation is clearly different and unique. As good as titanium is, it has one major disadvantage, it is too expensive. It is about 4-6 times more expensive than stainless steel. The high cost of titanium, which also made it to be scarce, and so, not a ready work-piece material for common experimental work. For this reason, many scientists do not have access to it and they are only left to generalize chip formation in titanium and its alloys with other less expensive and common work-piece materials in the group of so-called difficult-to-machine metals [2]. Background Chip Formation Theories Understanding chip formation is the first step to good chip control, a necessity for automated machining [3]. Theory of metal cutting recognises, mainly, the Merchant’s law of metal cutting, a schematic expression is as shown in Fig.1. This theory is based on the principles of single shear plane chip formation [4, 5]. Another dimension into the theory of metal cutting, according to Talantov [5] is illustrated in Fig. 2. In this case, the plastic deformation, forming the chip, takes place continuously within a shear zone consisting of a multitude of shear planes that are parallel in orientation to themselves.

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Figure 1. Chip formation theory based on single shear plane. (ñòðóæêà – chip, ðåçåö – cutting tool) [5]. A pioneering figure who stepped forward to institute successful empirical modelling of the machining process was Taylor sometimes as far back as 1880 [6]. It must be mentioned that some 10 years before that, in 1870, a scientist of the Russian Empire, Timme, had introduced what is now known as the Merchant’s law which only came into existence in 1945 [5]. Something must then be wrong with the history of metal cutting unlike that of other sciences. Though the theory of metal cutting started as far back as 1870 by Timme, it has not changed much till date. At any rate, both the so-called Merchant’s law and the theory suggested by Talantov could not be said to have completely solved all the problems of chip formation completely. This is as a result of the fact that there should have been different approaches on chip formation to the different work-piece materials, unlike where both laws and theories generalise all work-piece materials to be behaving in same way under the harsh cutting conditions.

Figure 2. Chip formation theory based on multiple parallel shear planes. (ñòðóæêà – chip, ðåçåö – cutting tool) [5]. Classification of Chip Forms Trent [7] generalized and classified all chips formed during metal cutting into three. Astakhov [3], classified chip formation into seven groups. In his own book, Kalpakjian [8], chip formation was classified into four groups. The confusion, in the first place, in these groupings is connected with the so-called continuous chips with built-up edges and the phenomenon that we shall refer to here, as the built-up edge phenomenon in chip formation whereby adhesion of some parts of the work-piece material sticks to the cutting tool surface to form an artificial cutting edge. This is not in any way doubting the existence of chips with built-up edges. The type of chips formed during turning of stainless steel, titanium and other metals in the group of metals generally termed difficult-to-machine metals are the chips that could rightly be called continuous chips with built-up edges. They are cyclical and segmental chips that are still joined together at the base. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Figure 3. Typical chip formation during turning of stainless steel showing identical segments of the chip. (X1500) For the benefit of this paper, it is absolutely important to state that the continuous chip with builtup-edges are taken to be only the type of chips, as shown in Fig. 3, which are segmented and cyclical in nature with each of the segments forming a built-up edge and in most cases are still joined together at the base. This type of chips, allowing some variations, is common with turning of different types of stainless steel as well as titanium and their alloys. Since titanium has been found, it has pushed other metals of interest to a lower stage. Before the discovery of titanium, stainless steel has been the pace setter after it pushed mild steel and iron to stages lower. Stainless steel lost out to titanium in properties, most especially in weight/strength relationship. Titanium is about 3-5 times lighter than stainless steel but 5-7 times stronger [1]. For this reason, just like in the early discovery of other metals, the discovery of titanium and its alloys went secret since all the positive properties are of importance, in the first instance, in the military and defence industries [1].

Figure 4. Typical chip formation during turning of mild steel. (X1500) Since technical books only treat the problems of titanium on the surface, many scientists, in the early periods of its introduction, do not have much reference [2]. This led to a lot of theoretical modelling, based mainly on assumptions, of happenings during turning of titanium. Others even try to write on titanium basing only on the events of turning like-metals. Others even turn titanium on micro speeds and generalize their finding for titanium. Very much unlike other metals, titanium also has a problem of classification [9]. This is not only that different countries classify the same titanium alloy differently, but, even within the same country, different companies do classify same alloy differently [9]. Despite these problems, it is very difficult to reject titanium and its alloys and so, engineers are sticking to it as much as possible.

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Figure 5. Predominant chip formation during turning of titanium and its alloys having unequal segments in size. (X1500) The introduction of titanium into engineering intensified the research into it and most especially in the field of metal cutting. Chip formation in titanium (Figures 5, 6 & 7) is different from that of similar metals though the chips, at first sight, look alike and only serious study with the aid of strong and powerful microscopes will reveal the differences [10]. Mild steel will, under normal conditions, have continuous chips during turning (Fig. 4) [10]. For any other chip to be produced, the cutting speed must have been over and above 120m/min, the wear of the tool must have been much more than the normally recommended and the stability level of the machine must have be exceeded. Another type of chips will be formed while turning stainless steel of different grades. This type of chips is called the segmented chip and are continuous with built-up edges (Fig. 3) [10]. A segmented chip will be formed while turning stainless steel of all grades not minding the type of tool material. Contrary to the belief of some scientists, the type of tool material will not have effect on the type of chip formed [5]. With the introduction of stainless steel, the development of cutting tools received a boost. Scientists were searching for ways of developing better tools to withstand the periodical load on the tool caused by the blocks of the segments of the chip as well as withdrawing the excessive heat from the cutting edge of the cutting tool. In other words, a segmented chip is not desired in production and should be avoided and prevented as much as possible. It is to be emphasized that the segments of the chips formed during turning of stainless steel are identical (Figure 3). Since segmented chips are also formed during turning of titanium and its alloys and at the same time titanium and its alloys are more expensive than stainless steel, scientists tend to develop models of turning of titanium basing mainly on turning of stainless steel and other like metals. Another fact is that titanium is much more difficult to machine than stainless steel. Let it also be noted that some scientists try to actually turn titanium to determine the process of chip formation for better understanding, the only problem is that, the cutting speeds are not industrial [2]. Titanium is turned in microspeeds and the results used to explain chip formation of titanium. This is not right since process of chip formation under the regime of microspeeds is very much different from that of industrial speeds. Many scientists even limit themselves to the theoretical and mathematical aspects alone in explaining the process of chip formation in titanium and its alloys without experimental backings.

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Figure 6. Chip formation during turning of titanium where the microstructures are more favourably oriented to the shear zone showing a more stable process resulting in a more continuous chip formation. (X1500)

2.

Methodology The term metal cutting throughout has been assumed to be only metal cutting process with the production of chips [5].

The work-piece materials used include titanium and its alloys, stainless steel and its alloys as well as mild steel. The cutting tool materials used are high speed steel (HSS) P6M5, double carbide cemented carbide tools – T5K10 and T15K6, as well as single carbide cemented carbide tools – BK6OM, BK100M, BK10X0M with very fine grain sizes, with fine grain sizes BK6M and BK10XTM and with standard grain sizes – BK6, BK8, BK10 and BPK15 (The cutting tool comes under the Russian Standard (GOST) 2209-69 as insert forms 0277A, which are bolted or fixed mechanically to the tool holder). The cutting regime is – cutting speed, V, = 5m/min – 100m/min, the feed of cut, s, = 5mm/rev and the dept of cut, t, = 3mm. The machine tool is a universal lathe machine. Each of the work-piece material is turned at different cutting speeds as stipulated above. The cutting tools were also varied in view of finding out the effects of the type of cutting tool materials on the process of chip formation. With the help of a quick stop mechanism that was mounted on the tool holder of the lathe machine, chip root specimens of the different work-piece materials were obtained. After obtaining these chip roots, they were prepared and made ready for study on microscopes. Making the chip root specimens ready entails polishing it, parallel to the chip direction and to the middle of the specimen in order to expose the external fixtures of the chip root. Polishing was made manually after the specimens have been embedded into a solution of cold working acrylic powder which later solidifies, thereby allowing the specimens to be held without hurting oneself or damaging the chip root. Different grades of abrasive materials were used in forms of dicks, plates and pastes. The polishing is made until the surface is as smooth as glass and without any scratches. The specimens were later stained, with related chemicals, to reveal the internal structures of the work-piece material as well as that of the cutting tool material. The staining exposes internal structures of the specimen at levels of work-piece material before and after being turned to chip. These specimens were later photographed for adequate studies. 3.

Results and Discussions After studying over 1500 chip roots of titanium and over 600 chip roots of both mild steel and stainless steel it could be said that as it could be seen in Figure 3, all the elements of the segmented chip, which occurs during turning of stainless steel, look identical. This shows that the process of chip formation, taking place during turning of stainless steel, is relatively stable. This fact helped in suggesting and recommending the optimal type of tool grade to be used to turn the metals in the group of stainless steel. In the case of mild steel as can be seen in Figure 4, the process of chip formation flows constantly and is stable. This also makes it easy to suggest better cutting tool materials as well as improved cutting parameters during the cutting operations. In the case of titanium and its alloys, the process of chip formation is not stable at all. The block structures of titanium and its alloy plays a major role in the process. The microstructural block of titanium pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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and its alloys play major roles in the chip formation process. Although, the type of cutting tool grade is important but, this does not affect the process of chip formation as widely believed by scientists. It was also noticed that the tool geometry though important, does not affect the process formation. Nearly in all cases, the microstructures of the chip material do not differ from that of the workpiece material (Figure 7). The shear zone, during the process of turning titanium, is not constant. This explains why there are no changes in the microstructures of both the chip and workpiece materials. This means that not all parts of the segmented chip passes through the shear zone.

Figure 7. Shear zone is reduced to a mere shear line during turning of titanium showing no changes in the structures of the chip material and workpiece. (X1500) The shear zone, when present, is reduced and even some times could not be called a shear zone but a “shear line” and passes through the boundaries of the microstructural blocks since they tend to be the weakest parts of the structures. The shear line some times passes through the microstructural blocks if it has a defect. The shear zone is sometimes present and makes the chip formation process flow as in the case of mild steel thereby producing a normal continuous chip (Figure 6). In Figure 5, one can see how the different structural blocks as well as their orientations to the shear zone determine the type and size of the elements of the segmented chip. The difficulty in obtaining a chip root could be considered as a major reason why scientists have never been able to relate or attribute, to this level, the effects of the structural blocks on chip formation process in titanium and its alloys. In the same way, it is very easy to notice that the elements of the segmented chip in titanium, unlike in stainless steel (Figure. 3), are not identical. Metal cutting process during the turning of titanium and its alloys is not stable. This shows that the blocks are very much responsible for the emergence of the elements of the segmented chips. In Fig. 6, it can be seen that the type of chip normally known to come along with turning of titanium and its alloys, but at the same time, a continuous chip formation could clearly be seen over a period of time. It was this continuous chip that caused the problem. This was explained as a favourable placement (orientation) of the predominant block in the microstructural level. It has been proved by some previous scientists that preheated titanium cuts better than a cold one [11]. A preheated metal looses some of its properties to heat and this changes its state, on the microstructural level, this means that the microstructures move with more ease than when cold. Preheating titanium and its alloys makes the blocks of the microstructures, which play predominant role in chip formation, be more easily displaced, moved or even torn to effect easy cutting and a “better” chip formation under the influence of the great cutting force. 4.

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At this point, it is to be stressed that: (a) microstructural blocks of titanium and its alloys play major roles in their chip formation; (b) the type of tool grades does not affect the process of chip formation in titanium and its alloys as widely asserted by scientists; (c) tool geometry though, very important, does not affect the process of chip formation in titanium and its alloys; (d) the shear zone, during the process of turning titanium and its alloys, is not constant. It sometimes appears and sometimes disappears; (e) the shear zone sometimes is so thin that it could be called a shear line and passes mainly through the boundaries of the microstructural blocks since they are the weakest points; (f) when there is a defect, the shear line could pass through the microstructural block itself. 5.

Acknowledgement The authors wish to thank the Volgograd State Technical University as an institution and especially members of staff of the Department of Advanced Manufacturing Technology for allowing the use of the departmental laboratories and other facilities for this research work as well as the assistance rendered during the course of the work.

6. References 1. Awopetu O. O., Dahunsi O. A., Aderoba A. A. (2005). Selection of Cutting Tool for Turning -Titanium Alloy BT5. AU Journal of Technology. Thailand. Vol.9, N1. 46 – 52pp. 2. Utkin E. F., Awopetu O. O, Kurchenko A. I., (1995) Effects of Structures of Titanium Alloys on cutting processes. Russian Academic of Science, Institute of Scientific and Technical information (VINITI) Journal No. 0240 (8) 10 – 13pp. (In Russian) 3. Astakhov V. P., Shvets S. V., Osman M. O. M. (1997). Chip Structure Classification Based on Mechanics of its Formation. Journal of Materials Processing Technology. Vol. 71. 247 – 257. 4. Astakhov V. P., Shvets S. V. (1998) A System Concept in Metal Cutting. Journal of Materials Processing Technology. Vol. 79. 189 – 199pp. 5. Talantov N. V. (1992). Physical Fundamentals of Cutting Processes, Wear and Chatter of Cutting Tools. M. Machinotroenie. 240p. (In Russian) 6. Merchant M. E. (2003). Twentieth Century of Machining in the United States – An Interpretative review. Sadhana. Vol. 28, Part 5. 867 – 874pp. 7. Trent E. M. (1984) Metal cutting. Butterworths & Co Publishers. UK. 245 pp. 8. Kalpakjian S. (1997). Manufacturing Processes for Engineering Materials. Addison-Wesley Publishing Company. 950p. 9. Awopetu O. O, Kurchenko A. I., Utkin E. F. (1995). Microstructural Classification of Titanium and its Alloys. Russian Academic of Science, Institute of Scientific and Technical information (VINITI) Journal No. 0234 (8) 4 – 6pp (In Russian). 10. Awopetu O. O., Ayodeji S. P., (in print): Effect of type of work-piece material on chip formation process. AU Journal of Technology. Thailand. 11. Amin N (1986).effect of Preheating of Metals on the Process of Metal Cutting. Unpublished PhD Dissertation. Volgograd Polytechnic Institute. Volgograd. USSR. 250p. (In Russian). pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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(ICERD08217) Á ÍÅW SURFACE FINISH BASED CRITERION OF MACHINABILITY OF MATERIALS IN TURNING G. PETROPOULOS*, N. HASSIOTIS, G. KAISARLIS Department of Mechanical and Industrial Engineering, University of Thessaly, Pedion Areos, 383 34 VOLOS, GREECE *corresponding author; email: [email protected] School of Mechanical Engineering, National Technical University of Athens, Heroon Polytechniou 9, Zographou, ATHENS, GREECE

Machinability of an engineering material denotes its adaptability machining processes concerning variables such as cutting forces, tool wear, and surface roughness. It stands for an exceptional technological property that helps the manufacturer to take crucial decisions and apply proper machining conditions for the workpiece material each time processed. Ranking of materials in view of machinability is usually achieved by experiments undertaken in turning operations and is based upon tool wear and tool life, and machinability data bases incorporate relevant data and indices mostly. To determine tool life is a time and money consuming task and with relatively low test reproducibility. And in cases of polymer materials this kind of testing is non feasible. A new machinability criterion is proposed in the present study that is oriented in the form of the surface texture imparted by turning process. The distortion of the regular ‘’arc-chain’’ shape of a turned surface could be considered as a measure of defect and consequently related to poorer machinability. In this regard, if tests of different materials are conducted under identical cutting factors, a classification based on this criterion is possible. In particular, three steels, a brass, a polymer and a polymer composite were tested against the proposed approach of machinability in turning. The cutting factors used and kept constant for every material were: a very small and a very high feed, a cutting speed above the region of cutting edge formation when cutting metals, a depth of cut rather small not to create dynamic problems and a carbide tool of negative rake angle, controlled to be free of wear throughout the tests. To obtain more machinability data that can be seen additionally or comparatively to the new methodology, the cutting forces were measured and the chips were characterized. Next, a multi-parameter analysis of surface texture was carried out and profile shape sensitive parameters were considered, like skewness (Rsk) and kurtosis (Rku) of the profile amplitude distribution, the spacing parameter (Rsm), the autocorrelation length (ë), the fractal dimension (D), ‘’Rk’’ parameters that describe the Abbott curve and of course the popular center line average (Ra) for general characterization [1]. Secondarily, pronounced waviness as an indication of increased machining difficulty is regarded through the ratio Ra/Wa.

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(ICERD 08238) EFFECT OF PASS REDUCTION ON ROLLING PARAMETERS USING REVERSE SANDWICH MODEL INTEGRATED INTO THE HOT ROLLING BLAND AND FORD’S THEORY O.J. Alamu, P. O. Aiyedun Department of Mechanical Engineering University of Agriculture, PMB 2240, Abeokuta, Ogun State, Nigeria e-mail: [email protected] [+234-803 385 8298] Abstract Hot flat rolling simulation by use of the Bland and Ford’s cold rolling (HRBF) theory confirmed the reverse sandwich effect in selected carbon steels at low strain rates. The Reverse Sandwich Model (RSM) was subsequently integrated into the HRBF theory for load and torque estimation. In this work, the effect of pass reduction on rolling temperature distribution, yield stresses and rolling load were studied for AISI Type 316 stainless steel (HCSS316). For this new simulation, at low and high strain rates, results showed that the ratio of experimental to calculated roll load and torque were higher at lower reduction than at higher reduction. These results confirmed excess load and torque in the hot rolling of HCSS316 at low reductions. This is in agreement with results obtained using Sim’s theory, HRBF theory and the RSM.

Keywords: Reverse sandwich rolling, Load, Torque, Pass reduction, Temperature.

1.

INTRODUCTION Several reports have appeared in print on disparity between experimental values and theoretical predictions of roll bite parameters such as roll load and torque during hot rolling of metals [1-5]. For hot rolling of AISI Type 316 stainless steel at low strain rates (0.01s-1 - 1.55s-1), reports have shown that theoretical predictions of rolling load and torque using simple rolling theories such as Sims and the Bland and Ford, and simple rolling temperature based on the mean entry temperature were not in perfect agreement with experimental measurements [1,6]. From hot rolling simulation, using a modified Leduc’s Program based on Sim’s theory, with the mean entry temperature as the mean rolling temperature, Aiyedun [1,6] reported (15-25)% excess load and torque compared with experimental values. He concluded that the underestimation of these parameters was as a result of temperature gradients leading to a higher strength of the surface layer of the slab compared with the bulk (called reverse sandwich effect) as well as precipitation hardening [1,6]. This was further reported to be more pronounced at low strain rates [7-8].

For temperature considerations, research into the reported disparities in the predicted and measured hot rolling parameters led to the proposition of the Reverse Sandwich Model (RSM) for AISI Type 316 stainless steel [1,6,8-9]. Integration of this model into hot rolling simulation based on the Bland and Ford’s cold rolling theory (HRBF) has been attempted and better agreement between measured and predicted parameters such as load, torque, yield stresses and temperature are evident [10]. However, only limited works have appeared in literature on this new hot rolling simulation. Besides, studies on the effects of different parameters on the hot rolling characteristics of metals and alloys have been enhanced through computer models [11]. In this work therefore, the effect of pass reduction on rolling temperature distribution, yield stresses and rolling load is investigated for AISI Type 316 stainless steel using reverse sandwich model integrated into the hot rolling bland and ford’s theory (RS-HRBF). pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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2.

450

METHODOLOGY 2.1 Hot Rolling Bland and Ford’s Theory

The Bland and Ford’s theory (BF) is a cold rolling theory, where sliding takes place throughout the arc of contact. It has however been found to be applicable to a hot rolling situation where sliding exists throughout the roll gap. This is the situation for hot rolling of HCSS316 at 900oC – 1200oC; reductions of 0 – 15%; strain rates of 0.07 – 1.5s-1; and geometrical factor of 4.0 – 20.00 as reported in the literatures [1,6,9]. Roll load, P and roll torque, T are respectively given by equations (1) and (2);   N     / P  R  S d  S d  (1)  0  N







T  2 R0 R

/

 Sd

(2) where,

h H .e h2

(3)

h  H1  H  .e h1

(4)

0



S   k .N . 

S   k .N .

R/ . tan 1 h2

H 2

R/ . h2

h  R / 2   .  1 1  r   h1  h2 

h R/ 2  .  1 (5) h2 h2

(6)

(7)

where; k

-

angle of entry (i.e. maximum value of ), radians instantaneous yield stress, N/mm2



-

angle subtended by a point on roll



surface w. r. t line joining roll centres, radians  N

-

Neutral angle, radians

R1 -

deformed roll radius, mm

R0 -

undeformed roll radius, mm

s

normal roll pressure N/mm2

-

h1,2 -

height (entry, exit)

Based upon an earlier approach of Sparling, which dealt with a mixed sliding-sticking situation in hot flat rolling, another model called Hot Rolling Bland and Ford (HRBF) was developed to calculate mean yield stress during rolling and these have been used to calculate rolling load and torque at low strain rates under sliding condition [1,6]. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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In rolling processes generally, it is vital to know the temperature distribution within the slab. Reports abound in literatures [9,12] that temperature is the dominant parameter controlling the kinetics of metallurgical transformations and the flow stress of the rolled metal. The mean temperature used by Aiyedun (1984) [1] in HRBF is; 

1





Tm  2  T  T  1

(8)

2

where T1 and T2 are entry and exit temperatures. The true yield stresses for load and torque calculation are respectively given as equations (9) and (10);

1 kp   



 kd

r

r



 kd

1 2 kg  kde  2 r  

0

e

where

(9)

0

h0  h , h0

(10)

0

r = reduction

2.1 The Reverse Sandwich Model, (RSM) The reverse sandwich model predicts the rolling reduction, rolling temperatures and temperature distribution along the through thickness of HCSS316. Detailed theoretical analysis of the model have been reported [7,10,13]. Percentage rolling reduction is given as: r

Hf  Ho X 100% Ho

(11)

With the specimen partitioned into 17 zones (n=1-17), the model’s prediction of rolling temperature follows equation (12) to (15). The temperature at the specimen’s core is given as: 1 (12) T  TM  Tf  CORE

2

where;

Tf

= =

furnace temperature, the mean rolling temperature TM 1 (13) TM  Tf  Ts  ] 2

where; Ts Ts 

where; K For For For

=

exit surface temperature,

Tf

(14)

K

=

Reverse Sandwich Model constant, values of which are functions of the rolling speed.

15  n  12, 1  n  4 and Tn+1 = Tn + 0.2 TDIST ………(a) 8 < n < 9, ………(b) Tn+1 = TDIST 5  n  7 and 11  n  9, Tn+1 = Tn + 0.04 TDIST ………(c)

(15)

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The rolling speed is related to the reverse sandwich model constant as follows: For 9  V  10, K = 1.59 …..(a) 10  V  45, K = 1.40 …..(b) (16) 45  V  100, K = 1.19 …..(c) 100  V  180,K = 1.16 …..(d) where; V = Peripheral velocity of rolls(mms-1) The approximate empirical equation of Farag and Sellars [14] was used in the model for determination of mean strain rate thus:

1.08V  R`

  2 0.25    ho  0.45   ln  h1h 2   hf   

 

(17)

where;  = reduction (mm) The Zener-Hollomon parameter was determined for each of the seventeen (17) zones along thickness (Z1Z17) using the proposition of Zener and Hollomon, [1,6]written as;

  Q    f   . exp    f ( Z )  RT    where; R T Z Q

= = = =

(18)

universal constant (J /mol..K) absolute temperature (oC) Zener-Hollomon parameter the energy that must be supplied by the thermal fluctuation to overcome obstacles such as dislocations.

The Z-values are uniquely related to the stress, and, hence the deformation of the material. For HCSS316 specimen under the prevailing rolling condition, Q = 460kJ / mol [1,6,9].

2.3 Simulation of the Model Simulation of the model was carried out using FORTRAN 77. The required input data are rolling speed, roll radius, furnace temperature, initial and final height of the specimen, and specimen width. From the output of the program, the temperature distribution, yield stress variation, rolling load and torque distribution across the thickness of the rolled specimen at different pass reduction are evident. 2.4 Experimental Data used in validating the new hot rolling simulation was obtained through preliminary metallographic, hot torsion tests, and hot rolling experiments performed on the as-received wrought AISI316 (with Nb, V and Ti inclusions) in the temperature range (600–1200) OC and strain rate range of (3.6X10-3 – 1.4) s-1. The wrought material was High Carbon Stainless Steel; ASME SA-240 from Heat 38256-2C, product of G. O. Carlson Inc., P.A., U.S.A. The material was cut into slabs of small sizes and hot rolled. The hot rolling experiments were performed on two laboratory mills; a 1000kN, 2-high, single stand, reversible mill with rolls of 254.0mm diameter by 266.0mm barrel length and 50T (498kN) capacity, 2-high reversible, Hille 50T rolling mill with rolls of diameter 139.7mm. 2.5 Program Validation The hot rolling experiment performed on AISI316 provided a data base for assessment of the validity of the simulated model. The computer program was executed using experimental values for eight specimens (H37H44). 3.

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In agreement with previous results of hot rolling simulation based on the BF, HRBF, Sims, and the RSM [1,6,7,9,11,13], Fig.1, showed similar pattern of variation in temperature across the specimen’s thickness. It is observed that the pattern of gradual temperature increase from the rolling surfaces to the specimen’s core remained consistent at different pass reductions (%r = 6.27-22.77 (at low strain rates) and %r = 6.6724.43(at high strain rates)) investigated. The results however showed a higher temperature gradient, penetrating deep into the material at low strain rates. This observation has earlier been made with the RSM [15]. 1100

1050

o

Rolling Temperature( C)

1000

950 H37, Strain Rate = 0.08, Reduction = 11.90% " H39, Strain Rate = 0.08, Reduction = 14.61%

900

H41, Strain Rate = 0.09, Reduction = 19.2% 850

H43, Strain Rate = 0.09, Reduction = 22.77% H38, Strain Rate = 1.00, Reduction 8.55%

800

H40, Strain Rate = 1.17, Reduction = 15.21% H42, Strain Rate = 1.28, Reduction = 20.15%

750 H44, Strain Rate = 1.37, Reduction = 24.30

700 0

0.94

1.94

2.94

3.94

4.94

5.94

6.94

8.02

9.02

10.02

11.02

12.02

13.02

14.02

15.02

16.04

Specimen Height

Fig. 1: Effect of Pass Reduction on Temperature Distribution at Low and High Strain Rates

From Fig.2, it can be observed that yield stresses for rolling load calculation decreases with increase in pass reduction for the specimens at low and relatively higher strain rates. A uniform pattern of variation of yield stress with specimen height from the rolling surfaces was also observed. 350

300

H37, Strain Rate = 0.08, Reduction = 6.27%

YieldStress for LoadCalculation

H39, Strain Rate = 0.08, Reduction = 14.54% H41, Strain Rate = 0.09, Reduction = 19.35% H43, Strain Rate = 0.09, Reduction = 22.77%

250

H38, Strain Rate = 1.00, Reduction = 6.67% H40, Strain Rate = 1.17, Reduction = 15.21% H42, Strain Rate = 1.28, Reduction = 20.15% H44, Strain Rate = 1.37, Reduction = 24.43%

200

150

100

50 0

0.94

1.94

2.94

3.94

4.94

5.94

6.94

7.96

8.96

9.96

10.96

11.96

12.96

13.96

14.96

15.96

Specimen Height, mm

Fig.2: Effect of Reduction on Yield Stress distribution at Low and High Strain Rates

Fig.3, revealed a uniform pattern of rolling load distribution with specimen through-thickness from the rolling surfaces. It is evident from the figure that rolling load increases with increase in pass reduction for the specimens at low and relatively higher strain rates. A similar relationship is thus implied for rolling torque. From Fig.4, it is observed that the ratio of experimental to calculated load (Pex/Pcal) decreases from 1.0 to 0.96 with increase in reduction from 6.27 to 22.77% for specimens H37-H43 respectively at low strain rates (0.08-0.09s-1) on mill A with 245.0mm roll diameter. Similarly, at relatively higher strain rates (1.001.37), (Pex/Pcal) decreases from 0.96 to 0.94 with increase in reduction from 6.67 to 24.43% for specimens H38-H44 respectively.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria 800

H37, H39, H41, H43, H38, H40, H42, H44,

700

Strain Strain Strain Strain Strain Strain Strain Strain

Rate Rate Rate Rate Rate Rate Rate Rate

= = = = = = = =

0.08, 0.08, 0.09, 0.09, 1.00, 1.17, 1.28, 1.37,

Reduction Reduction Reduction Reduction Reduction Reduction Reduction Reduction

= = = = = = = =

454

6.27% 14.54% 19.35% 22.77% 6.67% 15.21% 20.15% 24.43%

600

Rolling Load

500

400

300

200

100

0 0

0.94

1.94

2.94

3.94

4.94

5.94

6.94

7.99

8.99

9.99

10.99

11.99

12.99

13.99

14.99

15.99

Specimen Height, mm

Fig.3: Effect of Reduction on Rolling Load Distribution accross the Height of Hot Rolled Specimen at Low and High Strain Rates

1.25

1.2

1.15

Pex/Pcal

1.1

1.05

1

0.95 Low Strain Rates, Specimen H37-H43 High Strain Rates, Specimen H38-H44 Low Strain Rates, Specimen P55-P50 High Strain Rates, Specimen P47-P53 Linear (High Strain Rates, Specimen H38-H44) Linear (High Strain Rates, Specimen P47-P53) Linear (Low Strain Rates, Specimen P55-P50) Linear (Low Strain Rates, Specimen H37-H43)

0.9

0.85

0.8 18.2

18.4

18.6

18.8

19

19.2

19.4

19.6

19.8

Log (10)Z

FIG.4: Plots of ratio of experimental to calculated load against Zener-Hollomon parameter for different reductions for rolling at low and high strain rates on two mills

In a similar manner, from Fig.5, (Gex/Gcal) decreases from 1.18 to 0.84 with increase in reduction from 6.27 to 22.77% for specimens H37-H43 respectively at low strain rates. Also at higher strain rates, (Gex/Gcal) decreases from 1.22 to 0.93 with increase in reduction from 6.67 to 24.43% for specimens H38-H44 respectively.

1.25

1.2 Low Strain Rates, Specimen H37-H43

1.15

High Strain Rates, Specimen H38-H44 Linear (High Strain Rates, Specimen H38-H44)

1.1

Gex/Gcal

Linear (Low Strain Rates, Specimen H37-H43) 1.05

1

0.95

0.9

0.85

0.8 18.2

18.4

18.6

18.8

19

19.2

19.4

19.6

19.8

Log(10)Z

FIG.5: Plots of ratio of experimental to calculated torque against Zener-Hollomon parameter for different reductions for rolling at low and high strain rates on mill A

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On mill B, which has 139.7mm roll diameter, (Pex/Pcal) was also higher at lower reduction than at higher reduction for specimens P55-P50 investigated at low strain rates and specimens P47-P53 investigated at higher strain rates as evident from Fig.4. Mill B does not have torque meter, for which reason (Gex/Gcal) could not be discussed. Generally therefore, at low and high strain rates, the ratio of experimental to estimated roll load and torque were higher at lower reduction than at higher reduction. These results confirmed excess load and torque in the hot rolling of HCSS316 at low reductions. This is in agreement with results obtained through other hot rolling simulations based on Sim’s theory, RSM, BF and HRBF [1,6-9,13]. In comparison with published results [6-8,13], (Pex/Pcal) as well as (Gex/Gcal) values were generally lower using the RS-HRBF than those obtained through other hot rolling simulations based on Sim’s theory, RSM, BF and HRBF. This implies closer agreement between calculated and experimental rolling load and torque at varying reductions with the use of the RS-HRBF. 4. CONCLUSION It is hereby concluded that for hot flat rolling of Type316 stainless steel, pass reduction does not have appreciable effect on the temperature distribution pattern in the through-thickness of the material. Yield stresses for rolling load calculation decreases while rolling load and torque increases with increase in pass reduction at low and relatively higher strain rates. Also, the ratio of experimental to estimated roll load and torque were higher at lower reduction than at higher reduction.

5. REFERENCES [1] Aiyedun, P. O. “A Study of Loads and Torques for Light Reduction in Hot Flat Rolling”, Ph. D. Thesis, University of Sheffield. (1984). [2] El-Kalay, A. K. E. H. A. and Sparling, L. G. M. “Factors affecting Friction and their Effect upon Load, Torque and Spread in Hot Flat Rolling” Jnl. of the Iron and Steel Institute, vol.206, pp.152-163, (1968). [3] Beese, J. G. “Ratio of Lateral Strain to Thickness Strain during Hot Rolling of Steel Slabs” Jnl. of the Iron and Steel Institute, 210, pp. 433-436, (1972). [4] Oyinlola, A. K. “Photoplastic Analysis of Strain Distribution in Three-Dimensional Deformation in the Hot Rolling of Aluminium” Ife Journal of Technology, 2(2):13-20, (1990). [5] Afonja, A. A. and Sansome, D. H. “A Theoretical Analysis of the Sandwich Rolling Process” Int. J. Mech. Sci., 15 (1): 1 – 14, (1973). [6] Aiyedun, P. O. “Hot Flat Rolling Simulation by Use of the Bland and Ford’s Cold Rolling Theory for HCSS316 at Low Reduction and Low Strain Rates”, Proc, Int. AMSE Conf., 3 (1): 14 – 36. (1986) [7] Alamu, O. J. and Aiyedun, P. O. “A Comparison of Temperature Gradient in Hot Rolling at Low and High Strain Rates” J. Sci. Engr.Tech., 10 (1):4644 – 4654, (2003). [8] Aiyedun, P. O. and Sellars, C. M. “Effects of Fine Precipitate on the Strength of High Carbon SS316 Hot Flat Rolled at Low Reductions and Low Strain Rates” NSE Technical Transactions 33 (4): 67 – 100. (1998). [9] Aiyedun, P. O., Sparling, L. G. M. and Sellars, C. M., “Temperature Changes in Hot Flat Rolling of Steels at Low Strain Rates and Low Reduction.”, Pro. Instn. Mech. Engrs. Vol 211, Part B, pp. 261-254, (1997).

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[10] Alamu, O.J. “Integration of the Reverse Sandwich Model into the Hot Rolling Bland and Ford’s Theory for Load and Torque Calculations” M. Sc.Thesis, University of Ibadan, Ibadan, Nigeria, (2001). [11] Alamu, O.J., Aiyedun, P.O., Kareem, A. and Waheed, M.A. “Effect of AISI 316 Stainless Steel Geometry on Temperature Distribution During Hot Rolling at High Reduction” In Ibhadode, A. (eds), Advanced Materials Research -Advances in Materials and System Technologies, Vols. 18-19, pp. 195-200, Trans Tech Publications Ltd, Switzerland, (2007). [12] Serajzadeh, S., Taheri, A. K. and Mucciardi, F. “Prediction of Temperature Distribution in the Hot Rolling of Slabs” Modelling Simul. Mater. Sci. Eng. Vol.10, pp. 185-203, (2002). [13] B. Shobowale “The Reverse Sandwich Effect in HCSS316 Hot Flat Rolled at Low Strain Rates and Low Reductions”, M. Sc. Project Report, University of Ibadan, Ibadan, Nigeria. (1998) [14] Farag, M.M. and Sellars, C.M. “Hot Working and Forming Processes” Proc., Metals Society Conference, Sheffield, (1979). [15] Ojediran, J.O., Alamu, O.J. and Idowu, O. “Effect of Rolling Reduction on Temperature Gradient in Hot Flat Rolling of HCSS316” Jour. Engin. Apl. 4(1):1-13, (2004).

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(ICERD 08251) Surface roughness optimization of some machining parameters in turning operations using Taguchi method I. M. Dagwa Department of Mechanical Engineering, University of Abuja, Abuja Email: [email protected] Tel+234(0) 7082856572

ABSTRACT In this study an attempt has been made to optimize cutting parameters (cutting speed, depth of cut, and feed rate) in conventional turning operations. A Taguchi orthogonal array (L933) was used in surface roughness optimization of a solid round bar of mild steel material. The experimental runs were randomized; two skilled machinists were involved in the turning operation using the same machining parameters. ANOVA analysis was performed to identify the percentage contribution of the factors affecting surface roughness during machining. While the optimal cutting combination was determined by using the signal-to-noise ratio and the following results were obtained: speed (level 2) = 55.m/min, depth of cut (level 3) = 0.08mm, and feed rate (levels 3) = at 0.08mm/rev. A prediction of surface roughness was carried out using the optimal setting followed by a confirmatory test on the lathe. The result show that the confirmatory runs compared favourably well (96.44%) with the predicted surface roughness. Keywords: Taguchi design method, surface roughness optimization, machining parameters, ANOVA, SignalNoise ratio. 1.0 INTRODUCTION Centre lathe is one of the oldest, commonest and most versatile types of equipment used in the production of machine components in manufacturing workshops and industries. Cutting parameters in turning operations include depth of cut, feed rate, and cutting speed. In most of the machine tool shop, the turning operators use their experience through ‘trials and errors’ to arrive at a more preferred cutting condition. According to Aggarwal[1] over the last few decades it has been felt that there is an adverse effect of parameter selection when it is done in a not-very scientific practice. This practice leads to decreased productivity and poor quality of machined components due to sub-optimal use of machining capability. Most of the manufacturing Industries and machine tool shops in developing countries such as Nigeria are still depending on the skill and experience of the shop-flour. Some researchers [2] investigated the effect of tool angle, depth of cut and feed rate on the quality of surface finish form under conventional machining context. They found that to some extent these factors interact and that the main factor that influences the surface finish is rake angle. Surface finish in turning has greater influence on the quality of the product. Surface roughness (Ra) has received serious attention for many years [3]. It forms an important design feature in many situations such as parts subjected to fatigue, load, precision fits, fastener holes, and aesthetic requirements. It is very difficult in practice, to keep all factors under controls as required to obtain reproducible results. It has been reported [3, 4] that surface finish in turning has been found to be influenced in varying amounts by several factors such as feed rate, cutting speed, depth of cut, cutting time, work materials characteristics, work hardness, unstable built-up-edge, tool nose radius, work piece set-up, stability of machine tool, chatter, use of cutting fluids, cutting tool edge angles and tool nose radius. Therefore it is difficult, time consuming and costly to find all the variables that affects surface roughness in turning. Although the optimization of cutting conditions in turning operation has long been recognized [1], and several studies exist[5,6] which explore the effect of feed rate, spindle speed, and depth of cut on surface finish however, most of the work reported used CNC machines and the optimal settings were local optima. There are several optimization techniques [1] that can be used in metal cutting parameter optimization. One of the latest optimization techniques that are being applied successfully in the selection of process variables is Taguchi technique because of its robustness. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Hence, the aim of this study is to find the effect of the common variables such as feed rate, depth of cut, cutting speed on the surface finish during the machining operation. Furthermore, it is aimed at attaining an optimum parameter setting that will give a preferred surface roughness of the machined component in typical machine shop using a conventional center lathe. 1.1 Taguchi design method As reported [1], Genichi Taguchi is a Japanese engineer who has been active in the improvement of Japan’s industrial products and processes since the late 1940s. Subsequently, many Japanese firms have achieved great success by applying his methods. Zhang,et.al[7] also reported that Taguchi method has been widely applied in the US and Japan with great success recorded in optimizing industrial/production processes. The Taguchi technique uses a standard experimental design layout called the orthogonal array which originated from the factorial design. The method uses fewer numbers of experiments and the results generated have acceptable quality. Hence, the fewer the number of runs, the lower the cost and time is saved. The beauty of Taguchi design is that multiple factors can be considered simultaneously. The procedures for the implementation of Taguchi method is as follows: (i) Identify the noise factors, testing condition and quality characteristics (ii) Identify design factors and their suitable working levels. (iii) Select appropriate orthogonal array for the matrix experiment (iv) Conduct the matrix experiment. (v) Analyze the data and predict the optimum levels and performance (vi) Perform confirmatory runs to validate optimum condition. 1.1.1 Design of Experiment based on Taguchi Method To evaluate the effects of machining parameters on performance characteristics such as surface roughness, and the optimal machining parameter settings, a specially designed experimental procedure is required. Classical experimental design methods are too costly and time consuming to run. Therefore, Taguchi method, a powerful tool for parameter design was used to determine optimal machining parameters for a preferred surface roughness. The control factors are used to select the conditions for stability in design of manufacturing process, whereas the noise factor(s) denote all factors that cause variation [3]. There are many standard orthogonal arrays available in literature [8,9] each of the arrays is meant for specific numbers of independent design variables and levels. The factor levels for the cutting parameters were chosen as presented in Table 1 after a personal survey was carried out on the machining parameters used on the center lathe. Taguchi orthogonal array (L9 33) was used for planning the experimental layout as indicated in Table 2 while the performance response was transformed into signal-to-noise (S/N) ratio. In the Taguchi method, the term “Signal” represents the desirable target for good products and the term “noise” represents the undesirable value [10]. The (S/N) ratio which is considered appropriate to attain a better surface finish is Smaller- the-better, which is given as follows: S/N ratio = -10log10(

1 n 2  yi ) -----------(1) n in

Where n = number of replicate yi= Performance response (in this case surface roughness) Table 1 Factor levels for the Cutting parameters Factor Low level Medium level Cutting speed (rpm) 355 710 Depth cut (mm) 0.2 0.5 Feed rates ( mm/rev) 0.028 0.056

High level 1120 0.8 0.08

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Table 2 Experimental Design Layout using Taguchi orthogonal array L9(33) Experiment Cutting Depth Feed rates Randomisation number speed cut (mm/rev) (rpm) (mm) 1 355 0.2 0.028 1 2 355 0.5 0.056 5 3 355 0.8 0.080 9 4 710 0.2 0.056 3 5 710 0.5 0.080 6 6 710 0.8 0.028 8 7 1120 0.2 0.080 2 8 1120 0.5 0.028 4 9 1120 0.8 0.056 7 1.2 Metal cutting One of the common methods of converting a given stock of steel material to a desired shape such as a machine drive shaft is by metal cutting. During this process a cutting tool was used to cut away some portions of the material in form of chips as the work piece rotates against the tool. It was therefore necessary to know the machine power requirements for an anticipated feed, cutting speed and depth of cut for a particular material to see if the machine is capable of sustaining the desired power required to cut the material. Hence, for safe operations of the machine, the maximum allowable value for cutting power, P, which must not surpass the machine motor power (PMOT) considering the friction losses in transmission, should be adhered to. The actual power consumed in turning is given as [11]: Pactual =30 x 10-6(dc .f.V.Kc.K1) kW---------(2) Where: dc = Depth of cut (mm) f = Feed rate (mm/ rev) V = Linear cutting speed (m/min) KC = Specific cutting power for low carbon steel with C< 0.25% =2200 N/mm2 K1= Feed rate correction factor for specific cutting energy. Hence,

Pactual 

PMOT [12] ----------------------(3) 100 Where  is machine efficiency.

One of the challenges encountered in metal cutting is vibration of the cutting tool relative to the workpiece which can cause not only unacceptable surface finish imperfections but dimensional accuracy, tool life reduction, noise and even machine life [13]. During turning operations, one end of the cutting tool is fixed in the tool post while the cutting edge at the other end is free. This overhung is similar to a cantilever. As reported, from the theory of elasticity, the maximum deflection (y) of the tool occurs at the end of the tool which is given by [13]: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria y

Fc l 3 3EI

460

-----------------------------(4)

where Fc is cutting force. l- Length of the cutting tool overhung E –Young’s Modulus of the turning tool I – Second moment of area of turning tool cross sectional area (mm2) And the frequency of vibration (  ) of the turning tool when cutting is thus given by



0.4985 y

---------------------------------(5)

Hence, at different workpiece and cutting tool set-up, the frequency of vibration would defer which may yield corresponding difference in surface roughness. 2.0 METHODOLOGY 2.1 Materials: A mild steel round bar of Ø 25mm diameter x 1700mm length required for this work was purchased from Deidei market, Abuja. Other materials used included: Carbide tipped cutting tool with specification: ON 3712 S20, a parting tool SCUDAS 6383 P30 and a soluble oil as a coolant. 2.2 Equipment The equipments used in this work were as follows: Centre lathe - SM 16 B Tos Trencin (Made in Czechoslovakia) with motor power rating of 3.5 kVA; Speed range: 63- 4500rpm and feed rate range: 0.02 – 0.315 mm/rev. Surface roughness measurement device Surftest (stylus travel 2.54mm) Mitutoyo product, made in Japan and a vernier caliper. Microsoft Excel software was used for charting data and statistical analysis. 2.3 Experimental Method Experimental set-up and procedures: The experiments were performed on a center lathe (SM 16 B Tos Trencin). The mild steel solid round bar of diameter 25mm was mounted on a three-jaw chuck. A new tungsten carbide tool was used for each set of the experiments by the two machinists on the same center lathe. The tool was centered for effective cutting and during the turning operation a coolant was applied at the cutting edge of the tool at an approximate flow rate of 12ml/s. The cutting condition for each experiment was in accordance with the experimental layout in Table 2. Thirty-six (36) experiments were carried out in a random sequence to better the quality of the experimental result by minimizing biasness. For each of the experiment, the surface roughness was measure by using Surftest. Direction of measurement was taken parallel to the center line of the solid bar. While the stylus of the surftest travelled across the sample surface and its vertical movement transduced to electrical signals. Thereafter a print out showing the reading of the result and a graphical trace were obtained. 3.0 RESULTS AND DISCUSSION 3.1 Surface Roughness Thirty –six experiments were carried out by varying all the cutting parameters chosen to study the influence of these parameters on surface roughness and every machined component was taken to measure its surface roughness. Table 3 shows the results of the surface roughness measurements and their average values (µm Ra). The surface roughness measurements recorded in columns N1 and N2 were results of turned samples by pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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machinist A, while N3 and N4 were results of turned samples by machinist B. Also, the standard deviation(s), variance (s2) and the S/N ratio for each Table 3 Experimental results for surface roughness Exp. Run

N1 (µm)

N2(µm)

N3(µm)

N4(µm)

s2

S

Mean(x)

S/N

mm

Ratio(db)

1

9.83

10.69

6.02

5.14

2.748

7.553

7.920

-18.35

2

11.07

16.81

5.84

11.50

4.482

20.088

11.305

-21.55

3

10.71

6.36

10.17

5.76

2.55

6.503

8.250

-18.63

4.

6.77

10.32

6.46

2.57

3.168

10.036

6.530

-17.00

5

3.62

6.86

4.36

4.76

1.389

1.930

4.900

-14.06

6

4.43

10.75

2.93

1.87

3.978

15.823

4.995

-15.66

7

6.86

9.08

2.28

5.36

2.854

8.143

5.895

-16.11

8

3.11

2.26

14.83

9.90

5.847

34.183

7.300

-19.20

9

8.44

6.82

4.16

4.49

2.024

4.096

5.978

-15.89

Table 4 Averaged values of surface roughness at different levels of the factor setting Level

Speed

Depth of

Feed

Cut

rate

-

9.158

6.782

6.738

0

5.475

7.835

7.938

+

6.391

6.408

6.348

of the experimental run were computed using the Microsoft Excel software. The averaged values of surface roughness at different levels of the factor setting are presented in Table 4. The Taguchi signal-to-noise ratio for the smaller is better was used because the smaller the surface roughness (Ra) measured in µm the better was the surface roughness of the sample. Table 5: ANOVA for Surface Roughness (Ra) Factors Sum of Degree of

Mean of

%

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria Squares Speed Depth of

freedom

square

462

Contribution

22.0640

2

11.0320

74.88

3.2867

2

1.6430

11.15

4.1160

2

2.0580

13.97

cut Feed rate

Fig. 1 shows the signal-to-noise ratio for the surface roughness. Table 5 is the ANOVA for the surface roughness. Based on percentage contribution, this indicated that the cutting speed and feed rate were main factors that influenced the surface roughness which is in agreement with work done already reported [3,14]. Kirby [6] conducted a parameter design study in a turning operation using the Taguchi Method while considering a noise factor for CNC-turned parts. He reported that feed rate had the strongest influence on surface finish. However, in this study the cutting speed had the strongest influence. Table 6 is the surface roughness measurements data for the two machinists together with their corresponding difference (di) in their samples. A paired t-test as given in equation (6) was employed and it revealed that at 99.9% confidence level there was no significant difference between the surface roughness of the samples. This suggest that at the same machining parameter setting and using a new cutting tool for each set of experiment, it could be possible to attain an acceptable surface roughness of turned components from different machining workshops if the machines are stable.

-15

S/N Ratio

-20

-15

-15

S/N Ratio

S/N Ratio

-20

-20

Level 2 Level 3 Level 3 Level 1 Level data Table 6: 1Surface roughness (Ra ìm) Level measurement

Level 1 Level 2 Level 3 Feed Rate

Depth of Cut

Cutting Speed

Fig.1 Surface Roughness

Machinist

9.83

11.07

10.71

6.77

3.62

4.43

6.86

3.11

8.44

6.02

5.84

10.17

6.46

4.36

2.93

2.28

14.83

4.16

3.81

5.23

0.54

0.31

-

1.5

4.58

-

4.28

A Machinist B di

0.74

11.72

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria Machinist

463

10.69

16.81

6.36

10.32

6.86

10.75

9.08

2.26

6.82

5.14

11.50

5.76

2.57

4.76

1.87

5.36

9.90

4.49

5.55

5.31

0.6

7.75

2.1

8.88

3.72

-7.64

2.33

A Machinist B di

The average surface roughness measurement by machinist A and B were 8.044±3.54 ìm and 86.02±3.466 ìm respectively. The difference was attributed to the workpiece and turning tool setup since the experiments were performed using the same machine and each of the machinist used a new standard cutting tool on the same workpiece material. However, statistically, using the test of hypothesis we have: Null hypothesis Ho : ä = 0 (There is no difference between the surface roughness of the turned parts by the two machinist). Ha: ä  0 (There is difference between the surface roughness of the turned parts by the two machinist). Decision rule: If |t|  t n-1, á/2 |t|  t 17, 0.005 that is, in this case if |t|  2.898 then the null hypothesis will be rejected. Using the equation for paired t-test: t 

d Sd / n

[15]--------------------------(6)

Where: d=sample mean difference, Sd= standard deviation, and n = number of experiments. And for d=2.0217, Sd=5.02, n=18, t was obtained as 1.7086 .Decision: Since |1.7086|< 2.898, we may safely accept the null hypothesis. Hence, there is no significant difference between the surface roughness of the turned parts by the two machinist

3.2 Cutting power consumed in plane turning operation. As earlier stated for safe lathe operation, the cutting power for each experimental run should be less than its motor power rating. The powers consumed during the experimental runs were computed using equation 2 and the results are presented in Table 7. All the power consumptions were less than the motor power rating. Hence, the lathe was operated under a safe condition. The ANOVA (see Table 8) for the power consumption shows that the depth of cut and cutting speed had great influence on the power consumption. Table 7 Computed power consumption for the experimental runs Experimental

Power

run

consumption kW

1

0.0178

2

0.0844

3

0.1835

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria 4

0.0676

5

0.2294

6

0.1426

7

0.1447

8

0.1406

9

0.4264

Table 8: ANOVA Table for Power Consumption Factors Sum of Degree of Squares

freedom

Mean of

%

square

Contribution

Speed

3.1010

2

1.5505

33.45

Depth of cut

4.5790

2

2.2890

49.38

Feed rate

1.5919

2

0.7960

17.17

464

3.4 Optimum Cutting Condition The quality characteristic for the Ra is smaller is better; the smallest response is the preferred level for the parameter. This will give the largest S/N ratio since we always want the signal to be much higher than the noise in the machine set-up system. This is the criteria employed in the investigation to determine the optimal condition. Using the criteria of smaller Ra and larger S/N ratio, from Fig 1 the analysis of the results led to the conclusion that the optimal machining parameter setting in that range of parameters were: speed (level 2) = 55.m/min, depth of cut (level 3) = 0.08mm, and feed rate (levels 3) = at 0.08mm/rev. 3.5 Predictive Equation and Verification The use of predictive equation is the first step in verifying the optimum combination to predict a response value given the contribution of each factor at its level in the optimum combination. According to Vining[15] the equation is given thus: Y predicted = yexp + (yAo –yexp) + (yB+ - yexp) + (yc- – yexp) ---------------------------------(7) Applying this equation to the data in Tables 3 and 4, a predicted response at the optimum level setting was obtained thus; = 7.008 + (5.475 – 7.008) + (6.408 – 7.008) + (6.348 – 7.008) = 4.215ìm with a corresponding predicted S/N of -12.06 To verify this experimentally, confirmatory runs at the optimum levels were carried out 3.6 Confirmatory runs A confirmatory run is the final step in Taguchi experimental design procedure. The purpose of the confirmatory run is to validate the optimal settings deduced from the analysis of the result. This was carried pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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out after the optimal levels of all the parameters were identified. Three samples were machined at the optimal level setting by each of the machinists. Table 9 shows the result of the confirmatory runs. On the overall the average surface roughness of the confirmatory runs was 4.065 ìm. While the predicted surface roughness at the same parameter setting was 4.215 ìm. Hence the difference between the predicted and confirmatory runs surface roughness is 4.59%. When the results from the set of samples obtained by the machinist were subjected to paired t-test. At 99.9% confidence level there was no significant difference between the two sets of the samples. Applying equation (6) on data in Table 9, we have d = 1.23, Sd =0.3816, n = 3, and t was obtained as 5.58. Therefore, since 5.58< 22.327, we accept the null hypothesis. Table 9 Confirmatory test results Surface roughness (Ra) ìm Machinist 3.06 3.21 4.08 A Machinist

3.85

4.68

5.51

0.79

1.47

1.43

B di

4.0 Conclusions and Recommendation From the results obtained in this study the following conclusions can be made: (i)In this investigation the optimal cutting condition for turning a mild steel on a SM 16 B lathe were: speed (level 2) = 55.m/min, depth of cut (level 3) = 0.08mm, and feed rate (level 3) = at 0.08mm/rev. (ii)Cutting speed had the highest effect on the surface roughness of the turned part and feed rate had the next influence of the three factors considered. (iii)For the two skilled machinists they produced turned parts with Ra not significantly different at 99.9% confidence level. The difference in the average surface roughness obtained by using predictive equation with the surface roughness obtained from confirmatory runs by the mechanists was 4.59% which is quite satisfactory. (iv)These results suggest that in mass or batch production, turned parts produced in a small and medium scale manufacturing outfits where computer numerical controlled lathes are not available could be machined by different machinists using the same parameter setting to give satisfactory surface roughness. However, conclusive statement could not be made at this stage because other constraints need to be considered as a future work. Acknowledgements The author would like to sincerely express his gratitude to the HOD and Staff of Mechanical Engineering Dept., Federal Polytechnic, Nasarawa for their assistance in performing the experiment. 5.0 References [1] A. Aggarwal and H.Singh, optimization of machining Techniques – A Retrospective and literature Review. Sadhana Vol. 30, Part 6, (2005) pp 699 – 711. [2] A.C. Igboanugo and G.C.Ovuworie, Surface Roughness in Turning operation: Tool geometry, Depth of cut and Feed Rate Inter correlations. Nigerian Journal of Engineering Research and Development, Vol 6., No. 1. (2007) pp 1 – 9. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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[3] S.S. Mahapatra, A. Patnaik and P.K. Patnaik, Parametric Analysis and Optimization of cutting Parameters for Turning Operations based on Taguchi Method. Proceedings of the International Conference on Global Manufacturing and Innovation July 27 – 29, (2006). [4] P.V.S.Suresh, P.V. Rao and S. G. Deshmukh, A Genetic Algorithm Approach for Optimization of Surface Roughness Prediction Model, International Journal of Machine Tools and Manufacture 42 (2002)pp 675-680 [5] U. Zuperl and F. Cus, Optimization of cutting conditions during machining by using Neural Networks (2000) http://www.fs.uni - mb.si. [6] E.D.Kirby, A parameter Design Study in a Turning Operation using the Taguchi Method. Technology Interface/Fall (2006) pp 1-14.

The

[7] J. Z.Zhang, J.C.Chen and E.D. Kirby, Surface Roughness Optimization in an End-milling operation using the Taguchi Design Method, Journal of materials processing Technology 184(2007) pp 233 – 239. [8] Anon, “Taguchi Orthogonal Array Selector Matrix” (2003). http://www.freequality.org. [9] M.Grove and T.P. Davis, Engineering Quality and Experimental Design, Longman Group Ltd. UK, 1995. [10] S.J. Kim, K.S. Kim and H.Jang, “Optimization of Manufacturing Parameters for Brake Lining Using Taguchi Method”, Journal of Material Processing Technology, 136(2003) pp 202-208. [11] A.O.A. Ibhadode, Introduction to Manufacturing Technology, Ambik Press, Benin city, 1997. [12] R. Q. Sardinas, M.R. Santana and E.A. Brindis, Genetic Algorithm-based multi-objective optimization of Cutting Parameters in Turning Processes. Engineering Application of Artificial Intelligence 19 (2006)pp 127 – 133 –www. Sciencedirect. Com. [13] T. L. Tuleun and T.N.Guma, Analysis of Vibrations of a Non-Circular Boring Attachment on a Lathe, Nigerian Journal of Engineering Research and Development, Vol 5., No. 4. (2006)pp 33-42. [14] A.Hascalik, and U. Cayldos, International Journal of Advanced Manufacturing Technology(2007) http://www.Springerlink.com/content/v0322002106qk73w [15] G.G. Vining, Statistical methods for Engineers, Duxbury, USA, 1998.

NOMENCLATURE C = empirical tool factor d=sample mean difference, dc = depth of cut (mm) E –Young’s Modulus of the turning tool (N/mm2) f = feed rate (mm/rev) Fc = cutting force (N) I – Second moment of area of turning tool cross sectional area (mm2) K1= Feed rate correction factor. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria KC = Specific cutting power (N/ mm2) l- Length of the cutting tool overhung (mm) n = number of experiments/replicates. Sd= standard deviation, V = cutting speed (N/min) yi= Performance response (in this case surface roughness)  = is the mechanical efficiency of the machine ì = friction coefficient between the chip and tool  - frequency of vibration of the turning tool (Hz)

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(ICERD08269) ANALYSIS OF FORGING PROCESS BY THE WEIGHTED-RESIDUAL FINITE ELEMENT METHOD

John A. Akpobi and Christian O. Edobor Production Engineering Department, University of Benin, Benin City, Nigeria.

This paper reports an examination of the stresses and pressure fields set up at various cross-sections of a material during forging operation by the weighted residual finite element method. We present the numerical solution to the onedimensional differential equation which describes the pressures and stresses exerted on a forging. In preparation for the numeric, we split the blank into a finite number of elements and apply the Bubnov-Galerkin weighted residual scheme to obtain the weighted integral form; the finite element model is then developed from this weighted integral form which is solved to yield a three-parameter polynomial solution. Using a series of examples, we proceed to show that the weighted residual finite element method is capable of accurately predicting the pressures and stresses in an open die forging operation.

Keywords: Forging process; Bubnov-Galerkin weighted residual scheme; Finite element method.

[ For the detailed document go to page 1547]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

TECHNICAL SESSION 3C: WATER ENGINEERING

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(ICERD 08007) Water Quality and Occurrence of Water-borne Diseases in the Douala 4th DistrictCameroon. Andrew A Ako (1*), G E Nkeng (2), G E E Takem (1) 1* Hydrological Research Centre Yaoundé,BP 4110 Yaoundé-Cameroon. Tel: (237) 96 48 34 46 E-mail: [email protected]. 2 National Advanced School of Public Works Yaoundé. BP 510 Yaoundé-Cameroon, E-mail:[email protected] 1 E-mail: [email protected]

Abstract, . The study presents the monthly occurrence and age distribution of water-borne diseases in the Douala 4th District-Cameroon and establishes probable causes of diseases spread. Diseases of interest include gastro-enteritisis, amoebic dysentery, typhoid fever and cholera. Water-borne disease occurrence is observed to follow a seasonal pattern with peaks occurring between the months of January and May followed by drops between June and October and rises again from November. Children below 5 years were found to be more vulnerable to diarrhoea, gastro-enteritisis, amoebic dysentery while persons between 15- 44 years were more vulnerable to typhoid and cholera. Physico-chemically, water samples had turbidities varying between 5.5-86NTU, pH values between 4.2 and 7.1 and zero residual chlorine. Bacteriological analysis showed that the total coliform count was averagely 74/100ml, the faecal coliform count was 43/100ml and the faecal streptococci count was 27/100ml. Lack of access to potable water, absence of sanitation facilities and environmental factors could be advanced as the probable causes of water-borne disease spread. Key Words. Age distribution, Douala, Monthly occurrence, Water-borne diseases, Water quality. Methodology. In every epidemiological study, three parameters are very important and every such study should be based on them. These are; causes of disease spread, disease distribution amongst the community and preventive methods (Liese, 1992). Three research methods are used to establish the prevalence of waterborne diseases in the Douala 4th District. These methods are: collection of data on water-borne diseases, sanitary survey and physico-chemical and bacteriological analysis of water samples. The main objective of the collection of data on the prevalence of water-born diseases in our study area is to establish the distribution of these diseases with respect to age, sex and monthly occurrence. The sanitary survey has as objectives to establish the possible sources of the water-borne diseases i.e. food, water or poor sanitation and present the available water resources in the area. Water analysis for physico-chemical and bacteriological parameters is to establish the link between the presence of causative agents or pathogens in collected water samples and water quality. Data on these diseases is collected from some health institutions based in Bonabéri. These are; Bonassama District Hospital, CEBEC Protestant Hospital and St Albert LeGrand Dispensary. Additional data is obtained from the Provincial Delegation of Community Health. The parameters taken into consideration are monthly occurrence, vulnerable-age group and sex distribution. For the purpose of the sanitary survey, our research area was partitioned into two sectors: Sector I and Sector II.Sector I is made up of the following neighborhoods; Bonassama, Besseke, Bonamikano, Bonambappe, Quartier Bilingue, Grand Hangar and Ngwelle. Sector II is made up of the following quarters; Nkomba; Mabanda, Sodiko Ville and Village, Ndobo, Bonendalle, Bonjongoand Djeballe.

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Three neighborhoods were chosen from each of the sectors. Quartier Bilingue, Grand Hangar and Ngwelle were selected from Sector I and the following neighborhoods were chosen from Sector II, Mabanda, Ndobo and Sodiko Ville and Village. According to the Municipal Council and SNEC authorities, the above quarters have the lowest percentage coverage in terms of water supply and sanitation. These quarters are highly populated and swampy especially quarters like Mabanda, Quartier Bilingue and Grand Hangar. Habitation in these areas do not have any urbanization plan, no access roads and given that it is a low-income level community that inhabits these slums or shanty towns, there are virtually no existing water supply or sanitary services. The community is therefore obliged to resort to unprotected alternative water sources such as shallow springs and wells. In addition to this situation the lack of basic hygiene and sanitation awareness amongst the population especially concerning the placement of water sources such as wells with respect to sanitary installations such as pit toilets and septic tanks. All of these factors provide a fertile ground or haven for the establishment and proliferation of pathogens giving rise to water-borne diseases. The population in the six quarters is randomly sampled, with 50 households per neighborhood. This implies that the survey covers a total of 300 households. In many tropical rural areas and densely populated urban areas where untreated sources of water are used, periodic sanitary surveys of the raw water should be carried out to establish the level of risk of epidemic water-borne diseases to which the population is exposed. This survey includes an on -site inspection, evaluation of the water supply system and a bacteriological analysis of the water. From such a survey, sources of pollution can often be identified and measures taken to prevent future contamination (Okun (1987). Samples of water for bacteriological and physico-chemical analyses are collected from different water sources in the study area including 7 wells, a spring, a private tap and a public tap. These samples are analysed at the Water Analyses Laboratory of HYDRAC Douala using standard methods. The sampling locations and the neighborhoods chosen for the sanitary survey are shown in Fig 1.

Figure 1: Location Map of the Douala 4th District, Water Sampling Sites and Sanitary Survey

Results and Discussion. Monthly Occurrence of Water- borne Diseases in the Douala 4th District. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Figure 2: Monthly Occurrence of Water- borne Diseases in CEBEC Hospital. s 140 e 120 s a 100 C f 80 o 60 r e 40 b m 20 u 0 N

Diarrhoea Gastro-ent Typhoid Amoebic d

NB R L I Y E YGT T V C A E A RA N L U P CO E J F M P M U U A E ON D A J J S

Figure 3: Monthly Occurrence of Water- borne Diseases in St. Albert Legrand Dispensary.

140 ts n 120 ie ta p 100 f o re 80 b m 60 u N 40

Diarrhoea Gastro-ent Typhoid Amoebic d

20 0 N A J

B E F

R A M

IL R P A

Y A M

E N U J

Y L U J

G U A

T P E S

T C O

V O N

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Monthly Ocurrence

Figure 4: Monthly Occurrence of Water- borne Diseases in Bonassama District Hospital.

Generally, amongst the water borne diseases of interest, gastro-enteritis occupies the first position in terms of occurrence followed by, diarrhoea then amoebic dysentery, typhoid fever and cholera occupies the last position. According to data collected from CEBEC Hospital on the occurrence of these water-borne diseases, the general order of occurrence is respected but during the months of August and September this order is not respected. During the month of August, it is diarrhoea with 12 cases, which occupies the first position followed by typhoid, amoebic dysentery and gastro-enteritis, occupies the last position with 6 cases. There is a big drop in the registered number of cases during the months of June to October compared to the large number of cases from January to May On the other hand, data from St Albert LeGrand Dispensary indicates that diarrhoea is more prevalent than gastro-enteritis and only during the months of December with 7 cases for gastro-enteritis and January with 11 cases for gastro-enteritis where the general order of occurrence is respected. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Data from Bonassama District Hospital follow the established order of occurrence throughout the year with gastro-enteritis occupying the first position and amoebic dysentery occupying the last position. Looking at the monthly occurrence of each of the disease in the various health institutions, a seasonal disease spread pattern can be developed. During the months of January to May, the number of registered cases are high; it then drops during the months of July to October and starts increasing from November. This pattern can be attributed to the absence or presence of rainfall. During the months of the dry season when wells, springs and streams dry out, potable water becomes scarce and the population then resorts to drinking water of doubtable quality thereby making them vulnerable to these water-borne diseases. If rains do not come early or during prolonged dry seasons, water quality and availability problems become very critical .The above situation will only change if for a particular year there are early rains or prolonged rainy season. During the months of July to October, though one expects that being in the heart of the rainy season water scarcity problems should not exist but other factors favor the prevalence of water-borne diseases in the Douala 4th District community. As said before, the sanitary situation of the community leaves much to be desired. Most of the wells are shallow; the springs are exposed to faecal pollution and other sources of pollution. Few of the wells do have aprons, thus are accessible to the enormous surface runoff generated by the blocked, unmaintained drains. These wells are constructed very close to pit toilets whose levels rise during heavy rains making it possible for water from these toilets to infiltrate through the permeable sandy soils into these wells and springs. Secondly, it is during these months that there is an abundance of certain fruits like mangoes, oranges, grapes and vegetables. These foodstuff are mostly eaten uncooked, unwashed and for the cases of vegetables cultivated in marshy areas where water of doubtful quality is used thereby creating a haven for water-borne diseases. Average Age Distribution of Water-borne Disease Cases in the Douala 4th District. .

Figure 5: Average Age Distribution of Water-borne Disease Cases in the Douala 4th District in CEBEC Hospital

Figure 6: Average Age Distribution of Water-borne Disease Cases in the Douala 4th District in St. Albert Legrand Dispensary. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Figure 7: Average Age Distribution of Water-borne Disease Cases in the Douala 4th District in Bonassama District Hospital. In general, based on age distribution, the most occurring water-borne disease is diarrhoea followed by gastro-enteritis then typhoid fever and lastly amoebic dysentery. Generally, children below five years are more vulnerable to water-borne diseases contributing about 60% to the overall disease occurrence. Diarrhoea is most prevalent amongst children below 1 year followed by gastro-enteritis and the least prevalent is typhoid fever. This prevalence amongst babies can be attributed to the quality of water used to prepare baby food, poor hygiene practices of those handling these foods especially mothers and the dirty environment to which these children are exposed to. For children between 1-4 years, diarrhoea and gastro-enteritis have almost equal occurrence. Typhoid fever and amoebic dysentery are equally important. Typhoid fever is very much prevalent amongst the age groups 15-44 and 45 plus. This can be attributed to the tendency of adults being reluctant to go for vaccinations while young people especially children are targeted during vaccination campaigns. Sanitary Survey Data Table 1: Results of Sanitary Survey. Well depth We Public SN Quarter ll tap EC 1.5 1.5m 3m Sodiko 35 11 4 5 8 Ngwelle 42 2 6 11 10 Mabanda 45 5 0 1 38 Ndobo 48 1 1 12 10 Grand 41 8 1 4 37 Hangar Quartier 31 Bilingue

18

1

7

5

3.0-5.0 m 17 31 6 22 0

5 0 0 4 0

Disease prevalence Typho Diarr AD id hoea 2 9 1 6 5 0 10 15 5 7 19 2 13 9 8

19

0

3

>5m

9

13

Pit toilet users 32 39 42 43 47 41

AD = Amoebic dysentery With a sample population of 300, the sanitary survey came out with the following findings. 80.7% of those sampled make use of water as potable water, 15% from privatized public taps and 43% are SNEC subscribers. Of the 242 wells under consideration, 44.6% have depths between 1.5-3.0m; 39.3% between 3.0 and 5.0m; 3.7% have depths greater than 5.0m and 12.4% have depths of about 1.5m. Also, 81.3% of the sampled population make use of pit toilets and 18.7% have modern privies. The distance separating toilets and septic tanks from wells was also looked into.50.3% of the wells are separated from a well or septic tank by a distance less than 10.0m; 15.7% have separating distances of 10.0-15.0m while 16.7% are separated by pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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distances greater than 15.0m. 44.3% of the sampled population admitted they disinfected their wells with Sodium hypochloride (NaOCl) commonly known as “Eau de javel” or common salt. (NaCl) The neighborhoods in which this study is taking place are relatively densely populated and with a high density of wells and toilets compounded with the absence of a drainage network. In Mabanda for example, of the 45 individuals sampled, 42 use pit toilets as their excreta disposal facility. Sanitary facilities, wastewater and solid waste disposal pose considerable risks to the quality of available water resources. Seepage from latrines, septic tanks, defective wastewater pipes contaminates ground waters. In our study area, ground water levels are very high, that is why most of the wells hardly exceed 5.0m and the water table during the rainy season. Secondly, the soils in this area are composed mainly of sand having high permeablities hence communication between the shallow wells and the neighboring toilets is very much likely to occur. Added to this precarious situation is the fact that most of these shallow wells are located relatively close to sanitary facilities. The minimum distance separating a water source and a sanitary facility is 10.0m (WHO, 2004). In our research area, 50.3% of the wells are separated from a toilet by distances less than 10.0m. Three crucial elements are taken into consideration when evaluating the sanitary quality of well waters. They include; local geological conditions, distance from sources of pollution and protection from surface pollution (UNESCO, 1993). In Douala, 85% of the soils are sandy having high permeabilities with low water retention capacities (P.N.G.E, 1994). 78% of the wells in this area do not have concrete aprons; hence there is a high possibility of the pollution of wells by surface waters. Results of Bacteriological Analysis. Table 2: Results of Bacteriological Analysis of Water Samples. Quarter Samp Total Faecal Faecal Water le coliform coliform Streptoco source numb count/10 count/10 cci er 0ml 0ml count/10 0ml Ndobo 1 25 12 7 well Ndobo 2 21 17 4 Private tap Ngwelle 1 30 19 14 well Ngwelle 2 34 25 13 well Quartier 1 52 24 18 well Bilingue Quartier 2 43 30 10 well Bilingue Maband 1 37 25 15 well a Maband 2 63 41 22 well a Sodiko 1 27 8 17 spring Sodiko 2 38 13 8 Public tap The guideline values for bacteriological quality of potable water proposed by WHO (2004) is that the Total Coliform Count per 100ml of water sample = 0, Faecal (Escherichia coli) Count per 100ml of water sample = 0 and Faecal Streptococci Count per 100ml of water sample = 0. It is evident that all the water samples are from unacceptable potable water sources. Alcano (1983) proposed the ratio Faecal Coliform Count/ Faecal Streptococci Count in order to establish the origin of faecal pollution. This ratio is about 1.0-3.0 for human waste and 0.5-1.0 for animal waste. Van Buuren (1997) proposes a ratio of 1.0-5.0 for animal human waste. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Using the above ratios, the following origins of faecal pollution can be attributed to our water samples. Table 3: Probable Origins of Faecal Pollution of Water Samples. Quarter Sample Water Faecal Coliform Count/Faecal Probable origin number Source Streptococci Count Ratio of faecal pollution Ndobo 1 Well 1.7 Human waste 2 Private tap 4.3 Human waste Ngwelle 1 Well 1.4 Human waste 2 Well 1.9 Human waste Quartier Bilingue 1 Well 1.3 Human waste 2 Well 3.0 Human waste Mabanda 1 Well 1.7 Human waste 2 Well, 1.9 Human waste Sodiko 1 Spring 0.4 Animal waste 2 Public tap 1.7 Human waste

Results of Physico-chemical Analysis. Table 4: Results of Physico-chemical Analysis of Water Samples. Quarter Sample pH Turbidity Residual Water Source number Chlorine Ndobo 1 6.1 73 NTU 0 Well Ndobo 2 4.6 12 NTU 0 Private tap Ndobo 3 4.6 27 NTU 0 Well Ngwelle 1 4.8 9.3 NTU 0 Well Ngwelle 2 4.6 15 NTU 0 Well Ngwelle 3 4.8 17 NTU 0 Well Sodiko 1 4.2 5.5 NTU 0 Public tap Sodiko 2 5.7 19 NTU 0 Spring Sodiko 3 5.0 13 NTU 0 Well Grand Hangar 1 5.0 27 NTU 0 Well Grand Hangar 2 6.8 54 NTU 0 Well Grand Hangar 3 5.7 15 NTU 0 Well Quartier 1 7.1 44 NTU 0 Well Bilingue Quartier 2 6.1 22 NTU 0 Well Bilingue Quartier 3 6.1 86 NTU 0 Well Bilingue Mabanda 1 6.1 44 NTU 0 Well Mabanda 2 6.8 22 NTU 0 Well Mabanda 3 6.6 31 NTU 0 Well According to WHO (2004) water quality rules, potable water has to have a turbidity between 1and 5 NTU (Nephelometric Turbidity Units) and particularly for disinfection with chlorine, turbidity should be less than 1NTU, pH should preferably be less than 8.0 and free chlorine residual values are between 0.2 and 0.5 mg/l after a minimum contact time of 30 minutes. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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From the physico-chemical analysis results, only one sample has a turbidity value close to the accepted maximum value of 5NTU i.e. the sample collected from the public tap at Sodiko with a turbidity of 5.5 NTU. The rest of the samples have very high turbidity values with the third sample collected from the well at Quartier Bilingue having a turbidity of 86NTU which is seventeen times greater than the WHO guideline value of 5.0NTU. Only one third of the water samples have pH values between 6.5 and 8.5, which is the recommended WHO pH range for potable water. All the analysed samples have free residual chlorine values of 0. Thus most of the water sources are considered unpotable. Information gotten during the sanitary survey indicates that a majority of the wells are disinfected after being cleaned at the end of every dry season. Sodium hypochlorite (NaOCl) and Common Salt (NaCl). They are applied directly into the well in solid form. With the above practice, the absence of residual chlorine can be explained by the lack of knowledge of well owners on the disinfection procedure. The quantity of NaOCl used is very small compared to the amount in the wells due to the high cost of the disinfectant. Furthermore, they know very little of the guiding principles of chlorination particularly it’s controlling factors like pH, temperature and concentration. The frequency of chlorination of the wells is too short given the number of individuals who fetch water from them. Chlorinating once or twice a year is not enough due to the high pollution risk brought in by the uncontrolled consumer population. In addition, the influence of the high turbidity values is felt in the high chlorine demand generated by these high turbidity values. The high turbidity values do indicate the presence of various substances especially organic matter containing nitrogenous compounds. These nitrogenous compounds react with the chlorine to form chloramines and chloro phenols, which give the water odour and some of the suspended matter, can form cancerogeneous substances like trihalomethanes Desjardins (1980). Given the wrong exploitation of the chlorination process, it is not surprising that there is a high prevalence of water-borne diseases in this community because there is no disinfectant to eliminate the intrusive microorganisms responsible for these diseases or the existing disinfectant is in very small concentrations. Conclusions. In this study we have reported the occurrence and distribution of water-borne diseases in the Douala 4th District community through the use of data collected from health institutions operating in this area. It has been established that gastro-enteritis is the most prevalent disease followed by diarrhoea, amoebic dysentery and typhoid fever is the least prevalent A seasonal disease spread pattern has been proposed in which the months of the dry season are thought to be critical though disease spread is not limited to this period. Age vulnerability to water–borne diseases has revealed that children below 1 year are more vulnerable to diarrhoea and gastro-enteritis while individuals above 15 are more vulnerable to typhoid fever. This disease prevalence has been attributed to a poor hygiene and sanitation environment, presence of naturally porous sandy soils and the consumption of bad quality water. The bacteriological contamination of the water has been suggested to be of human origin and has been favoured by the lack of mastery of the chlorination process for potable water treatment. To eradicate or better still to reduce the occurrence of water-borne diseases in the Douala 4th District community, contributions have to come from the affected population, health personnel, water engineers and the local council authorities. They all must understand that water is life, has no price and this community have a right to this water given life. References. [1] Alcano L.E, Fundamentals of Microbiology.3rd Edition, Addison-Wesley Publishing Company, New York, 1983. [2] Cheesbrough. M., Medical Laboratory Manual for Tropical Countries. Volume II, University Press, Cambridge, 1984. [3]Desjardins M. (1980). Le traitement des Eaux (Water Treatment). Editions de l'Ecole Polytechnique, Montréal. pp.32-60. [4] Hunter P. (1997). Waterborne Disease: Epidemiology and Ecology. John Wiley & Sons. London. [5]Liese B. (1992). Organising and Managing Tropical Disease Control Programs. World Bank Technical Paper.167 (30), 17-23. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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[6] Nga N. E., Savino A., Pasquerella C.and Ngo Ntamack V. (2006). Comment aborder un thème de santé publique au Cameroun: salubrité de l’eau destinée à la consommation. (How to undertake a Public Health Theme in Cameron: cleanliness of drinking water) Le Pharmacien d’Afrique.No.196.Novembre 2006. 19-26. [7] Okun D. A. (1987). Community Piped Water supply Systems in Developing Countries. World Bank Technical Paper. 60 (5 6), 40 [8]P.N.G.E (1994). Diagnostic de la situation de l'Environnement de la Province du Littoral (A Diagnostics of the Environmental situation of the Littoral Province). Coordination Cell of P.N.G.E, Douala. [9] Tanawa E., Djeuda Tchapnga H.B., Ngnikam E., Temgoua E. and Siakeu E. (2002). Habitat and Protection of Water Resources in Suburban Areas in African Cities.Building and Environment.37 (2002) 269-275. Elsevier. [10] SNEC (2004). Schema Directeur d’Amenagement de Douala ( Master Plan of Douala) -Annexe 3, Eau PUFAC- Cameroun.30-41. [11] UNESCO (1993). Water and Health, IHP Humid Tropics Programme Séries.3. Place de Fontenoy, 5 Paris. [12]UNEP/WHO (1997). Water Quality Monitoring- A Practical Guide to the Design and Implementation of Freshwater Quality Studies and Monitoring Programmes. [13] Van Buuren J.C.L.Jr (1997). Sewerage and Wastewater Treatment 2nd Edition, Wageningen University Press, The Netherlands.1 -29. [14] WHO (2004).Guidelines for Drinking Water Quality. WHO,Geneva. [15] WHO (2004). Water, Sanitation and Hygiene Links to Health, Facts and Figures. [16] WHO (2000). Global Water Supply and Sanitation Assessment 2000 Report.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

479

(ICERD08009) DOMESTIC WASTEWATER TREATMENT WITH A VERTICAL COMPLETELY DRAINED PILOT SCALE CONSTRUCTED WETLAND PLANTED WITH CORCHORUS OLITERIUS Lacina Coulibaly*, Issiaka Savané, Germain Gourène * Author for correspondence: Dr Lacina Coulibaly, UFR-SGE 02 BP 801 Abidjan 02, Côte d’Ivoire. E-mail: [email protected]

Developing countries are faced with the problem of degradation by release of urban wastewater into the waterbodies. Eutrophication of these waters in densely populated areas causes loss of biodiversity and formation of toxic algae blooms which endangers drinking water supply and limits recreational activities (Carpenter et al., 1998; Smith et al., 1999; WHO, 2003). This is essentially due to the anthropogenic nutrients containing in these wastewaters. This situation may continue in the future because water pollution continues to increase in developing countries due to population increase in their megalopolis and also due to lack of budget to provide metropolises with conventional wastewater treatment processes (WHO, 2000). Consequently, there is a need to develop a sustainable wastewater treatment system adapted to these countries realities. Constructed wetland (CW) seems to be an alternative technology to treat such wastewater. The CW can easily be integrated in the urban environment to treat wastewaters (Billore et al., 1998; Cooper et al., 1996). Moreover CW is an economical wastewater treatment system compared to conventional biological sewage treatment (Kadlec and Knight, 1996). In developing countries, land price is not so high and the weather is generally favorable to plants, algae and bacteria growths, thus making CW a practical option. A pilot scale constructed wetland planted with Corchorus oliterius was developed for domestic wastewater treatment. The reactor system was composed of rectangular beds realized in cement. Each bed was filled from the bottom to the top with 0,1 m of gravel (15/25 mm) and 0,30 m of white sand from the Ebrié lagoon. Two beds planted with yang C. oliterius plants (high density: 40 plants/m²; low density: 10 plants/m²) and one control (unplanted bed) were used to perform the experiment. The beds filtrates pH was neutralized to 7. The planted beds removed the COD (low density = 61%, high density = 65%) more than the control (54%). Nutrients were also best removed in the planted beds (NH4+: 67%, PO43-: 52%) than in the control (NH4+: 11%; PO43-: 56%). The increase of the plant density had any statistical significant impact upon pollutants removal. However, this augmentation increased the bed performance. The plants leaves were less contaminated at 0,9 m above the bed surface, suggesting this height for their harvesting.

Key-word : Domestic wastewater, constructed wetland, treatment, Corchorus oliterius.

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(ICERD08012) PRETRAITEMENT DES EFFLUENTS D’UNE INDUSTRIE TEXTILE PAR UN FILTRE A SABLE PERFORE LATERALEMENT A ALIMENTATION INTERMITTENTE Lacina Coulibaly1*, Patricia Olga Tchehué2, Issiaka Savané2 1

Laboratoire d’Environnement et de Biologie Appliquée (LEBA), UFR-Sciences et Gestion de l’Environnement, Université d’Abobo-Adjamé. 02 BP 801 Abidjan 02, Côte d’Ivoire 2 Laboratoire de Géosciences et Environnement (LGE), UFR-Sciences et Gestion de l’Environnement, Université d’Abobo-Adjamé. 02 BP 801 Abidjan 02, Côte d’Ivoire *Auteur de correspondance : Dr Lacina Coulibaly: e-mail : [email protected]

La préservation d’un meilleur cadre de vie, oblige à lutter contre toutes les formes de pollution de l’environnement. Les effluents industriels constituent l’une des sources principales de la pollution environnementale (Kadirvelu et al., 2003), notamment les industries textiles qui utilisent divers produits chimiques (colorant, soude, etc.) et ceux-ci se retrouvent dans les effluents desdites industries (Chiou et al., 2003 ; Bhole et al., 2004 ; Sanghi et al., 2006). Lorsque ces effluents sont rejetés dans les eaux de surface, ils colorent celles-ci même à de faibles concentrations (5µg l-1) (Pierce, 1994 in Santhy et Selvapathy, 2006 ; Ceyhan et Baybas, 2001 ; Robinson et al., 2002 ; Chiou et al., 2003 ; Rozada et al., 2003 ; Maurya et al., 2006). Par ailleurs, certains de ces produits et leurs dérivés (amines toxiques) sont cancérigènes, mutagènes et toxiques pour les organismes vivants (Meehan et al., 2000 ; Fanlo et al., 2004 ; Sarioglu et Atay, 2006 ; Rajeshwari et al., 2001 ; Banerjee et Dastidar, 2005 ; Wang et al., 2005 ; Senthilkumaar et al., 2006). Outre les colorants, ces effluents contiennent des matières en suspension (MES) (> 500 mg l-1), de l’azote (> 30 mg N l-1), du phosphore (> 1 mg P2O5 l-1), des métaux lourds, une demande chimique en oxygène (DCO) > 500 mg l-1, avec une faible (25% ) fraction biodégradable (Banerjee et Dastidar, 2005 ; Bawa et al., 2006 ; Kim et al., 2003; Santhy et Selvapathy, 2006 ; Rajeshwari et al., 2001 et 2003). Les méthodes classiques de traitement de ces effluents sont très couteuses pour les pays en développement. Dans ce contexte, les méthodes alternatives moins onéreuses doivent être investiguées. C’est ainsi que le potentiel d’épuration d’un filtre à sable perforé latéralement a été étudié sur les effluents de l’industrie textile UNIWAX à Abidjan. Différentes configurations (perforation : 5x30, 10 x30 et 20 x30 cm2) de filtre à sable ont été utilisées. Le pH, conductivité, absorbance des eaux usées ainsi que des filtrats à 436, 525 et 620 nm ont été suivis. Les résultats pertinents obtenus sont une baisse de pH  11 à un pH compris entre 6 et 9, une désalinisation et une décoloration de 45% de l’eau usée à 436 nm. Le coefficient d’absorption spectrale (á) des effluents bruts baisse aux différentes longueurs d’ondes investiguées. Le meilleur rendement d’épuration de l’effluent a été obtenu avec le filtre perforé avec 5 cm d’ouverture. La filtration intermittente sur un lit de sable avec 5x30 cm2 d’ouverture est une alternative prometteuse pour le prétraitement d’effluent textile.

Mots-clés : Traitement ; adsorption ; filtre à sable ; effluent d’industrie textile ; colorant.

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(ICERD 08053) Bioremediation of Refinery Wastewater Using Inorganic Fertilizer (NPK 15: 15: 15) K. O. Obahiagbon and C. E. Akhabue Department of Chemical Engineering, University of Benin, Nigeria Phone: 234 803 355 3215 or 234 802 336 1732 ABSTRACT This study investigated the treatment of refinery wastewater using inorganic fertilizer. The biological method of treatment using the process of bioremediation was used. Inorganic fertilizer (NPK 15: 15: 15) was used to biostimulate the microorganisms present in the wastewater. Five samples of the refinery wastewater with equal pollution load were each treated with different amount of fertilizer that is 5, 10, 20, 30 and 40g/l of the refinery wastewater. The following physiochemical parameters; Biochemical Oxygen Demand, pH, Chemical Oxygen Demand, Total Suspended Solids, Dissolved Oxygen and Total Hydrocarbon Content of water were monitored for a period of thirty- five days. From the results obtained, the Biochemical Oxygen Demand was observed to have dropped from 68.71 – 30.23m/l; 68.71 – 23.92mg/l; 68.71 – 22.11mg/l and then 68.71 – 21.86mg/l for the 5, 10, 20, 30, and 40g/l of the refinery samples respectively. Similar decreases were also observed for the other physiochemical parameters, except for the pH and dissolved oxygen, which increased with time. It was observed that the 40g/l sample was more effective in the thirty –five days of the study and these results met the FEPA standard for Biochemical Oxygen Demand, which is within the range of 30 – 35mg/l. Hence, the method of bioremediation using fertilizer in the treatment of wastewater from oil refinery, can be applied on a large scale treatment Keywords: Refinery Wastewater, Biotreatment, Inorganic Fertilizer, Environment. INTRODUCTION Environmental pollution can be defined as any discharge of material or energy into water, land or air, that may cause acute (short) or chronic (long term) detriment to the earth’s ecological balance or lowers the quality of life.[1] Pollutants may cause primary damage with direct, identifiable impact on the environment or secondary damage in the form of minor disturbances in the delicate balance of the biological food web that can be detected only over a long time period. The sources of water pollution are varied, involving almost every significant human activity. Most generally done is the dumping of wastes; sewage, agricultural wastes, effluent, etc into water ways. This discharge of wastewater from industries, like all water-borne waste presents a potential hazard to natural water systems. These liquid waste streams can contain organic matter and materials which are directly toxic to the aquatic system. The waste chemicals from oil refinery are not exactly toxic,[2] the main problem is that many of them are rapidly oxidized by taking up oxygen in the water, and the resultant effect is that it leads depletion of oxygen which ultimately leads to the death of fishes and other marine lives. The lack of oxygen also stops the bacteria oxidation of sewage and organic waste which is the process of self purification.[3] Treatment of wastewater is carried out in order to reduce the spread of communicable diseases caused by pathonogenic organisms and to prevent the pollution of surface and ground water. The treatment of wastewater is carried out by a combination of physical unit operations and chemical and biological unit processes before the end products can be dispose off.[10] Bioremediation is used in the treatment of wastewater. It is an aerobic process that involves the biological oxidation of wastewater using microorganisms.[4] It can be done in two different ways: biostimulation and bioaugmentation.

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In biostimulation, adjustments are made to the wastewater to enhance microbial population already present. This includes adding a nitrogen source, a phosphorus source and a countless number of innumerable myriad of trace minerals and making appropriate pH adjustments. This method assumes that every organism needed to accomplish the desired treatment results is present. Bioaugmentation is the controlled addition of specially formulated biocultures to assist those found naturally in wastewater. It is done in conjunction with the development and monitoring of an ideal growth environment in which these selected bacteria can live and work.[4] In most cases, the targeted organic contaminants either serves as the food source or are co-metabolized. Essential elements are added to the food source to provide the required nutrient levels and water itself provides the media in which the bacteria function. After treating the wastewater, it should properly be dispose off, either by dilution in streams and rivers, land application or re-use in agriculture or crop irrigation. METHODOLOGY Sample Collection Wastewater sample was collected from the final effluent from the Warri Refinery and Petrochemicals, Ekpan, Warri. The samples were temporarily stored in black colored jerry cans at room temperature. This was to avoid the penetration of light, and thus prevent photosynthesis from taking place. Determination of pH Apparatus: A Corning Model 235H glass electrode pH Meter, loss electrode and reference electrode stirrer. Procedure: The electrode was inserted into the refinery wastewater. The value was taken when a steady value was obtained on the screen. Determination of Total Suspended Solids (TSS) Apparatus Filter paper, glass fibre fitre funnel. Procedure The glass fibre filter funnel was dried to constant weight. The refinery wastewater was shake vigorously and a 100ml. of this was filtered through the dry glass fibre filter funnel. The liquid passed through it while the solids were retained. The glass fibre and the solids were dried to constant weight at 103oC – 105oC. The difference in weight gave the weight of the suspended solids. Suspended solids=

M gf Vs

 100mg / l 

Where: Mgf =mass of Solid on glass fibre Vs = volume of sample Determination of Total Dissolved Solids (TDS) Apparatus; Evaporating basin, Steam bath and oven Procedure From the filtrate obtained from the TSS determination, 50ml of this was transferred into a clean previously weighed evaporating basin, and the solution was evaporated on a steam bath. The dish was then transferred into an oven and dried at 103oC to a constant weight.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria TDS=

483

WBR  WB 100mg / l  V1

Where: WBR = Wmeight of Basin Residue WB =Weight of Basin V1 = 50ml Determination of Total Hydrocarbon Content [13] Apparatus: 1 litre Separating Funnel, distillation flask Reagent n- Hexane Procedure: 500ml of the refinery wastewater was transferred into the 1 litre separating funnel and shaken vigorously with 25ml n-Hexane. The organic layer was then allowed to separate. After the separation, the aqueous layer was returned back into the funnel, shaken with another 25ml of n-Hexane and the organic layer recovered. This procedure was repeated until all the hydrocarbon content had been recovered. The n-Hexane extract in the distillation flask was distilled off until about 10ml was left in the flask. The condenser was then disconnected and the remaining solvent was boiled off.

THC 

( A  B )  100 mg / l  V2

Where; A = weight of flask + hydrocarbon B= weight of distillation flask V2 = 500ml Determination of Chemical Oxygen Demand (COD) In contrast to the BOD test which takes a minimum of five days to calculate, the COD test which can also be used to measure the content of organic and inorganic matter present in wastewater takes only hours to determine. Apparatus: Refluxing flask, bulb pipette, burette, retort stand and clamp. Reagents: Mercury sulphate, HgSO4, 0.125M K2Cr2O7, Ag2SO4 – H2SO4 solution, Ferrous sulphate solution (FeSO4), Ferroin indicator. Procedure: 20ml of the sample wastewater was pipetted into the refluxing flask followed by 0.4g of HgSO4. 10ml of 0.125M standard K2Cr2O7 was then added using a bulb pipette. 30ml of Ag2SO4 – H2SO4 solution was also added to the flask. A blank was prepared with all the above reagents excluding the wastewater. The two separate mixtures were refluxed for 2 hours, cooled and the titrated with ferrous sulphate solution, using six drops of ferroin as an indicator. The blank containing 20ml of distilled water was also titrated to obtain the morality of FeSO4 solution. The Chemical Oxygen Demand (COD) was calculated as follows:

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria COD 

484

( B  T )16000 M 20

Where: B = Blank titre (i.e. volume of FeSO4 used) T= Sample Titre M= Molarity of Ferrous Sulphate

Determination of Dissolved Oxygen (DO) Apparatus: Erlenmeyer flask, 300ml bottle, pipette, burette, retort stand and clamp Reagents: MnSO4 Solution, Alkali- azide – iodide reagent (NaOH + NaI + HNaN3) Concentrated H2SO4, 0.0125M sodium thiosulphate solution (Na2S2O3), starch indicator. Procedure: The dissolved oxygen in the effluent wastewater was determined by the alkaline – azide modification of the Winkler’s method, which is based on the oxidation of iodide ion (I-); (contained in the alkali – azide – iodide reagent) to iodine I2, by the dissolved oxygen of the sample and the titration of the iodine by sodium thiosulphate using starch indicator. A 300ml bottle was filled with the wastewater to the brim to exclude air bubbles and 2ml of MnSO4 solution was added to the bottle well below the surface of the effluent, followed by 2ml of alkali – azide iodide reagent. The bottle was stoppered and inverted several times to ensure complete mixing. The bottle was then allowed to settle for five minutes. 5ml of concentrated H2SO4 was carefully added to the bottle and the bottle shaken until a clear solution was obtained. An aliquot (20ml) of the clear supernatant was then transferred into an Erlenmeyer flask titrated with 0.0125M sodium thiosulphate solution, using five drops of starch solution to a clear and sharp end point. The calculation for the dissolved oxygen (DO) is given as: DO=

16000MT V

Where; M=Molarity of thiosulphate T= Titre volume of thiosulphate V= Volume of aliquot taken for titration Determination of Biological Oxygen Demand (BOD) The biological oxygen demand is the amount of oxygen required by the bacterial for breaking down to simpler substances the decomposable organic matter in water, wastewater or effluent. It is usually determined by measuring the amount of dissolved oxygen present in the sample before and after incubation in the dark at 20oC for five days. Apparatus: Two 300ml BOD bottles, tin foil, incubator, air compressor flask, burette, retort stand and clamp, pipette. Reagents: Phosphate buffer (KH2PO4, K2HPO4, NaHPO4) Magnesium Sulphate (MgSO4. 7H2O) Calcium Chloride (CaCl2) Ferric Chloride (FeCl3. 6H2O) Settle Sewage Suspension. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Procedure: Preparation of Dilution Water; About two litres of freshly distilled water was aerated by bubbling air from an air compressor for thirty minutes. Thereafter, 1ml each of the phosphate buffer, magnesium sulphate, calcium chloride and ferric chloride solution were added to the aerated water followed by 2ml of settled sewage suspension. The flask was shaken to ensure thorough mixing of the water and the added nutrients. Biological Oxygen Demand (BOD) Determination Into each of the two 300ml BOD bottles, 9ml of the waste water sample was transferred and the bottles were filled to the brim (to exclude air) with dilution water. The dissolved oxygen was determined immediately in one of the bottles to represent the initial dissolved oxygen. The other bottle was stoppered, covered completely with tin foil to exclude light and stored for five days in a thermostatically controlled incubator at 20oC. At the end of the period, the bottle was removed from the incubator and dissolved oxygen determined for the sample using the modified alkali- azide Wrinker’s procedure. The calculation is given as;

BOD 5 

( DOo  DO5 ) x

Vb VS

Where; DOo = initial DO

Vb = Vs =

Volume of bottle Volume of sample used.

Effect of Nutrient Addition to Wastewater on BOD5 Five levels of fertilizer sample (NPK – 15, 15, 15) were added to the waste water samples in different amount of: 5, 10, 20, 30 and 40g per litre in the 300ml BOD bottles. The solutions were then seeded with 1ml of a suspension of settle sewage and incubated continuously for thirty-five days at 20oC in a cooled incubator. On the fifth, tenth, fifteen, twentieth, twenty-fifth, thirtieth and thirty-fifth day, 9ml samples were withdrawn from each bottle, transferred into fresh 300ml BOD bottles filled with dilution water and incubated for five days. At the end of the five days, the dissolved oxygen left in each solution was determined by the modified alkaliazide Winkler’s procedure as described for dissolved oxygen. RESULTS AND DISCUSSION The variation of some of the physiochemical parameters of water – Biological Oxygen Demand BOD5, pH, Chemical Oxygen Demand COD5, Total Dissolved Solid (TDS), Total Hydrocarbon Content (THC) and Dissolved Oxygen were monitored to ascertain the degree of effectiveness of the method of treatment. Biological Oxygen Demand The biological oxygen demand for the five samples of equal pollution load but with different amount of fertilizers was studied. It was observed from figure 1 that the value dropped appreciably from 68.71mg/L – 30.23; 23.92; 22.14, 22.11, and then 21.86mg/L for the 5, 10, 20, 30, and 40g/L samples respectively.

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80 70

B O D (m g /L )

60 5g

50

10g 40

20g

30

30g 40g

20 10 0 0

5

10

15

20

25

30

35

40

Time (days)

Figure 1 Variation of Biological Oxygen Deamnd with Time

The sample containing 40g/L of fertilizer was more effective in the degradation of hydrocarbons by microorganism compared to the other sample. This is as a result of the fact that microbial activity was higher in the 40g/L sample, since there was sufficient nutrient present and this stimulated them to biodegrade the hydrocarbon faster than the other samples.[5] pH As the microbial activity increased, the pH of the media increased with time as show in figure 2. For the 5g/L of sample, the increase in pH was initially slow at the beginning of the investigation. After the twentieth day, the pH increased from markedly from 7.34 to 8.14mg/L. This was not the case for the 40g/L sample, as the rate of increase was much higher in the first week of investigation. The pH increase from 7.34 to 8.03 after the first five days and increasing to 8.45 at the end of the thirty-fifth day. This can be explained by the fact that microbes feed on hydrocarbons, breaking down organic acids and mineral acids into simple component such as carbon dioxide, methane and water.[7] This increases the pH and enhances the growth of microorganisms.

8.6 8.4 8.2 5g 8

pH

10g 20g

7.8

30g 7.6

40g

7.4 7.2 0

5

10

15

20

25

30

35

40

Time (days)

Figure 2:Variation of pH with Time

Chemical Oxygen Demand As shown in figure 3, there was an appreciable drop in the chemical oxygen demand, COD as the overall reduction ranges from 55.89% to 64.07%. The 5g/L sample had a reduction in COD from 257.2mg/L to 113.44mg/L representing a percentage drop of 55.89%, while the sample containing 40g/L of fertilizer had the greatest drop in COD from 257.2mg/L to 92.4mg/L representing a percentage decrease of 64.07mg/L. This indicates that both the organics and inorganic present in the refinery wastewater have been oxidized to a large extent.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

487

Chem ical Oygen Dem an d

300 250 200 5g 10g

150

20g 30g

100

40g 50 0 0

5

10

15

20

25

30

35

40

Time (days)

Figure 3: Variation of Chemical Oxygen Demand

Total Suspended Solids The drop in the total suspended solids with time can be seen from figure 4. A range of 96.8% to 99.92% reduction was obtained over a period of thirty five days. This could be attributed to the fact that the microorganisms were able to derive nutrients and energy for growth and reproduction from the nutrients supplied, such that they were able to use the waste in suspended form and converting them into less harmful form as water and carbon dioxide. 14

T o ta l S u s p e n d e d S o l i d s

12 10 5g 8

10g

6

20g 30g

4

40g

2 0 0

5

10

15

20

25

30

35

40

Time (days)

Figure 4: Variation of Total Suspended Solids

Total Hydrocarbon Content, THC The greatest drop in the Total Hydrocarbon content was observed for the sample containing 40g/L of fertilizer. The THC decreased from 16.9 to 0.8mg/L after the period of investigation. There was an appreciable decrease in the sample containing 35g/L of fertilizer. The THC for this sample decreased from 16.9 to 0.6mg/L. These drops could be explained by the fact that the microorganisms were stimulated by the addition of nutrients to act on the hydrocarbons present in the wastewater. Dissolved Oxygen There was a somewhat uniform increase in the Dissolved Oxygen Content of most of the samples under consideration, except that of the 30 and 40g/L sample. There seems to be a drop in the rate of increase in dissolve oxygen between the tenth and fifteen day of investigation as seen in figure 6. For this period under review, the rate of increase in dissolved oxygen 0.175% and 0.07% for the 30 and 40g/L sample. After this period there was a steady increase of dissolved oxygen in the samples. This therefore indicates that considerable oxidation has been accomplished during the period of investigation.[1]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

488

18

16

Hydrocarbon Content (mg/L)

14

12

10

5g 10g 20g

8

30g 40g 6

4

2

0 0

5

10

15

20

25

30

35

40

Time (Days)

Figure 5: Variation of Hydrocarbon Content with Time

62 61 60

Dissolved Oxygen (g/L)

59 58

5g 10g 20g

57

30g 40g

56 55 54 53 52 0

5

10

15

20

25

30

35

40

Time (Days)

Figure 6: Variation of Dissolved Oxygen with Time

CONCLUSION Bioremediation process of treating wastewater has proven to be efficient, flexible and more cost effective. On the basis of the study carried out, it can be seen that the analysis was a success, since most of the results obtained were within the standards sets by the Federal Environmental Protection Agency (FEPA). Thus this biological method of treating wastewater is highly feasible. REFERENCES [1] B. C. Punmia and A. Jain (2003) Waste Water Engineering, Laxmi Publications Limited, New Delhi, India [2]

Obahiagbon, K. O. (Editor, Ibhadode A. O.) (2002) Wastewater and Wastewater Treatment in Environmental Pollution; Causes Effects and Solution

[3]

Atlas, R. M. (1991) Microbial Hydrocarbon Degradation – Bioremediation of Oil Spills. J. Chem. Tech Biotechnol.

[4]

Marks R. E., Field S. D., Wojtanowicz A. K. and Britenbeck G. A. (1992) Biological Treatment of Petrochemical Wastes for Removal of Hazardous Polynuclear Aromatic Hydrocarbon Constituent. Wat. Sci Tech.

[5]

Berwick P. G. (1984) Physical and Chemical Conditions for Microbial Oil Degradation, Biotechnology and Bioengineering

[6]

Atkinson, B. and Mavituna, F.(1991) Biochemical Engineering and Biotechnology, Handbookm, Stockton Press, New York .

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[7]

Rosenburg, M. Gutnick, D. L. and Rosenburg E. (1983) Bacteria Adherence to Hydrocarbons, Microbial Enhanced Oil Recovery. Penn Well Publications Company. Tulsa, Oklahoma, U.S.A.

[8]

Fan C. Y. and Krishnamurthy, S. (1995) “Enzymes for Enhancing Bioremediation of Petroleum Contaminated Soils”, A brief review. Journal of the Air and Waste Management Association.

[9]

Lapinska, J. (1989) Soil Biotreatment: Bacterial degradation of Hydrocarbon Contamination in Soil and Water, Chemistry and Industry

[10]

Badmus, M. A. O. (Editor, Ibhadode A. O.) (2002). Pollution in the Oil Refinery, Environmental Pollution Causes, Effects and Solution

[11]

Swanell R. P. J. (1991). Bioremediation of Petroleum Hydrocarbons in Water, Technical Summary Paper, Warren Spring Laboratory, Stevenage, Hertfordshire, UK

[12]

Ademoroti, C. M. A. (1979) “Studies of Physiochemical Methods of Wastewater Treatment”, Ph.D. Thesis, University of London.

[13]

Lindgreen C. (1957) “Measurement of Small Quantities of Hydrocarbons in Water”, JAWWA 49 : 55

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

490

(ICERD08054) BIOREMEDIATION OF CRUDE OIL CONTAMINATED WATER USING Pseudomonas aeruginosa AND INORGANIC FERTILIZER (NPK 15: 15: 15) K. O. Obahiagbon and C. E. Akhabue Department of Chemical Engineering, University of Benin, Nigeria Phone: 234 803 355 3215 or 234 802 336 1732

Major oil spills attract the attention of the public and media. In recent years, this attention has created a global awareness of the risk of oil spills and the damage they do to the environment. However, oil is a necessity in our industrial society, and major sustainers of our lifestyle. In Nigeria, the major causes or factors which lead to oil spillage are; corrosion/burst/rupture of pipelines, sabotage of well heads and pipelines, blow outs, oil production operations and other engineering activities like transfer of oil from one ship to another ship and also from depot tanks to tankers. The presence of oil can affect the use of water for industrial and agricultural purposes. Oil on the surface of inland water and on banks is a nuisance as it causes interference with recreational activities and also a menace to wild life. It may also lead to a possible fire hazard. Bioremediation as a method of treating crude oil contaminated water was investigated in this work. Two types of bioremediation processes; biostimulation and bioaugmentation were applied, i.e. the use of various amounts of Pseudomonas aeruginosa and a fixed quantity of inorganic fertilizer (N. P. K 15: 15:15) as a means of removing the hydrocarbon compounds from the crude oil contaminated water. In this work, five experimental samples of equal pollution load were used. The control sample, S c contained 20g of fertilizer treated with 8  10 5 cfu . The remaining four samples S1 , S 2 , S 3 and S 4 contained 20g of fertilizer each and

1 10 5 cfu , 2  10 5 cfu , 4  10 5 cfu and 8  10 5 cfu respectively. Results obtained from the analysis of the physiochemical properties carried out after nine weeks of investigation shows that a high percentage of oil is removed (94.11%, 92.80%, 88.92%, 86.7% and 77.57% for S1 , S 2 , S 3 , S 4 and S c respectively. pH, Turbidity, Biochemical and Chemical Oxygen Demand for these samples were also measured during the period of investigation. The Biochemical Oxygen Demand obtained for the S 4 sample after the nine-week period of investigation was found to fall within the Federal Environmental Protection Agency (FEPA) standard of 30mg/l (maximum). The value obtained was 27.50mg/l. A pH value of 6.60 was also obtained for this sample after the same period.

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491

(ICERD08062) MULTI-PARAMETER MODEL FOR COMPUTING HEAD LOSS DEVELOPMENT IN DEEP-BED (DEPTH) FILTERS USED FOR PRODUCTION OF POTABLE WATER O. E. Ekenta 1, a and B. U. Anyata 2, b 1 Civil Engineering Dept, Nnamdi Azikiwe University, Awka, Nigeria. 2 Civil Engineering Dept, University of Benin, Benin City, Nigeria. a E-Mail:[email protected] b E-Mail:[email protected]

This research work focuses on the effects of clogging due to accumulation of solids in the pores of packed beds used as granular media filters for the production of potable water. Modelling of the filtration process will require an assessment of the changes that take place within the filter media pores during filtration including its effects on filtrate quality and on the development of head loss during filtration. In gravity (deep-bed) filtration the driving force is a measure of the pressure drop for overcoming media resistance. Filter averaged data obtained from pilot filter test runs was used for the formulation of a logarithmic model relating head loss rise [HLR] to filter run length (time) [FRL]. A multi-parameter model was subsequently conceived and formulated by coupling this logarithmic model with Carmen-Kozeny’s clean bed head loss equation. The multi-parameter model is made up of seven key parameters namely, head loss, filter run length, friction factor, media depth, filtration velocity, bed porosity and filter grain size. It would be applied in the computation of head loss values in gravity filters at increasing run times during a filtration cycle. The model will be applied as a predictive tool for design and operation of dept filters. It will therefore facilitate the work of designers and managers of water treatment works.

Keywords:

multi-parameter,

clogging,

packed

beds,

modelling,

head

loss,

gravity

filtration.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

492

(ICERD 08064) DRINKING WATER QUALITY MONITORING IN ADO-EKITI AND ENVIRONS BY FOLORUNSO, OLATUNJI PETER1 AND OMOTOSO, TOYIN2 CIVIL ENGINEERING DEPARTMENT, FACULTY OF ENGINEERING UNIVERSITY OF ADO EKITI, NIGERIA 1 [email protected] 2 [email protected] ABSTRACT The water cycle is an obvious mode of transmission of enteric diseases. Bacteriologically polluted water is potentially dangerous to health because of possible outbreak of typhoid, dysentery and cholera epidemics. In this paper major sources of drinking water in Ado Ekiti and its environs were examined for physical, chemical and biological qualities. These consists of wells in Adebayo, Ajilosun, Odo-Ado and other suburbs; most popular sachet waters (pure water) produce in Ado- Ekiti and the Pipe-borne water from the state water cooperation (Ureje treatment plants). The results were analyzed using t-distribution method of data analysis and World Health Organization (WHO) Standard was applied. The wells were found to be a little more acidic. All the samples showed high calcium content and some gave total hardness value above WHO standard. 70% of the samples, failed bacteriological test. Samples examined give a wider coverage of drinking water sources in Ado-Ekiti, Ekiti State. Key words: Sachet water, Wells and quality INTRODUCTION World Health Organization (WHO) World Water Day Report of 2001 revealed that only about one third of the Worlds potential fresh water can be used by man for various purposes due to environmental, geographical and financial factors [1]. Pollution from municipal, industrial and agricultural wastes has also contributed to the poor quality of water available [2]. Water cycle is an obvious mode of transmission of enteric diseases [2]. Bacteriologic ally polluted water is potentially dangerous to health because of possible outbreaks of diseases [3]. Poor quality water may have adverse effects, causing avoidable economic and human losses [5, 6]. Water contributes much to health; however, water’s protective role is largely unseen and taken for granted in Nigeria. [7, 9], Water contributes to health directly within households through food and nutrition and indirectly as a means of maintaining a healthy, diverse environment [8, 6], these two precious resources – water and health together could enhance prospects for development. The WHO (1976), reported that about 1.5 billion people worldwide drink filthy water and up to 25,000 people die each day in the world, from water related infections and the figures are increasing. Since there is an increasing demand for potable water in Nigeria and the inadequacy of the supply makes it imperative that any available source is carefully protected and monitored. MATERIALS AND METHOD Drinking water sources were sampled from different locations in Ado-Ekiti. The locations give a wider coverage of drinking water sources, within the metropolis and its environs. Water sample were taken from wells, sachets water (Pure water) and pipe borne water from the State Water Corporation. The above samples represent the major sources of drinking water in Ado-Ekiti. Physical, Chemical and Bacteria analyses were carried out using the following apparatus: Electrode Digital Oxygen Meter, Clean Test Tubes, Bunsen burner, Turbidimeter, pH meter, Pipette, Quebec Colony Counter, Bacteriological Wire-Loop and Methane.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

493

The Physical parameters examined include, temperature, colour, appearance, odour, and taste, while the chemical parameters include the dissolved oxygen, carbonate and bicarbonate, chlorine, calcium and magnesium ions, iron etc and Lastly the bacterial analysis. WHO standard was adopted for the results.

RESULTS AND DISCUSSION The result of the analysis of physical parameters of water samples from various sources within Ado-Ekiti and environs are summarized in table 1. Results of the Chemical test are summarized below in Table 2. The result of the bacteriological analysis is as summarized in the table 3. Table 1: Physical parameters of the samples PARAM SAMPLE SAMPLE SAMPL SAMPL SAMPL ETE A B EC ED EE RS

SAMPL EF

Taste less

Taste less

Taste less

Taste less

Taste less

Taste less

Appea rance

Clea n &cle ar

Clea n&cl ear

Clea n&cl ear

Clea n&cl ear

Clea n&cl ear

Clea n&cl ear

Odour

Odou rless

Odou rless

Odou rless

Odou rless

Odou rless

Odou rless

Temp eratur e (0c)

25.60

25.80

26.0

25.40

25.30

25.40

Colou r (Hu)

5.00

5.00

5.00

5.00

5.00

5.00

Turbi dity (NTU )

5.00

10.00

10.00

3.50

3.50

0.50

Condu ctivity (Ns/co m)

10.50

8.25

8.05

2.55

3.48

2.15

PARAMETE RS

Table 2: Chemical parameters of the sample SA SA M SAM SAMP MP PL PLE LE A LE E C D B

SA MP LE E

SA MP LE F

PH

5.50

5.5 0

5.50

7.00

7.00

7.00

Hardness

100

60

60

70

100

100

Iron

0.10

0.1

0.10

0.10

0.10

0.10

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria 0 Calcium

151.10

14 6.3 0

142.9 0

70.5 0

160. 00

160. 40

Magnessi um

58.56

58. 56

56.00

4.86

4.86

15.5 6

Bicarbon ate

4.88

3.6 6

3.93

6.10

6.10

7.93

Carbonat e

0

0

0

0

0

0

Chloride

22.73

68. 49

69.70

141. 80

70.9 0

216. 25

Chlorine

0.13

0.1 6

0.11

0.12

0.10

0.15

Residual chlorine

0.67

1.4 0

1.55

0.30

0.30

0.30

Acidity

0.25

0.3 0

0.25

0.20

0.20

0.20

6.85

6.3 0

6.49

7.00

7.30

5.32

Dissolved Oxygen

Table 3: Bacteriological analysis of the samples MOST PROBABL E NO OF E.COLI Source of Water COLIFOR NEGATIVE M OR PSTIVE ORGANIS M 100MOL SAMPLE F

TI

PIPE BORNE WATER

T2

SAMPLE E

TP1

SATCHET WATE R

TP2

SAMPLE D

TP1

SATCHET WATE R

TP2

SAMPL EA

WLA

NIL

2750

NIL

Negative

Positive

Negative

COLONIES/ML GROWING ON EMB AGARD @370C

PLATE COUNT REMARKS

NIL

Good

NIL

Good

10

Unsatisfactory

11

Unsatisfactory

NIL

Good

NIL

Good

2

Unsatisfactory

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494

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria WLI

WLB

SAMPL EB

WL2A

WL2

WL 2B

SAMPL EC

WL 3A

WL3

WL 3B

750

250

1000

Positive

Positive

Positive

4

Unsatisfactory

1

Unsatisfactory

1

Unsatisfactory

3

Unsatisfactory

4

Unsatisfactory

495

The result was analysed using charts and the t – Score method of data analysis. The t – test is an inferential statistical method used to generalize the observation from a sample over the entire population from where the sample was drawn. If X represents the variable of interest the mean of X which is defined as E(X) and the standard estimated error in X obtained from the sample represented as SX. Given these two qualities E(X) and S(X), a new variate t is defined as (1):

to =

n( x  o ) s( x )

 ( x  x) Where S(x) =

2

n 1

n

= Number of samples being considered.

x = Mean of samples under consideration S(x) = Sample variance x = Variable of interest µ0 = Degree of freedom of t – distribution. Biological Test: The well samples are found to contain some harmful bacteria one of the sachet water sample - E contained the highest value of 2750 MPN of Coli form organisms. Physical Parameters Colour and Odour: These are not objectionable; The samples examined are tasteless and odourless. Turbidity: On the average, the samples are within the WHO recommended limit of 5.0 NTU. Conductivity: The conductivity of the samples ranges from 2.15NS/cm to 10.50NS/cm. This is below the 250NS/cm permitted by the WHO (1993). Chemical The dissolved oxygen of the various samples ranges from 5.35ppm ± 7.2ppm, this is within the recommended range. PH: The pH value of the well samples is acidic. This is due to the presence of carbonate in the well samples. Carbonate and Bicarbonate: The carbonate and bicarbonate contents of all the samples are within the permissible limit of 150 mg/L CaCo3 recommended by WHO. Hardness: The samples are within the limits of 70mg/l Caco3 recommended by WHO. Iron: The iron concentration of all the samples has the same value of 0.1mg/l. This is within the recommended limit of 0.2mg/L of Iron content for dinking water.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

496

Coliform organisms

/ 100 ml (MPN)

300 0

250 0

200 0

150 0

100 0

500

0 Sample A

Sample B

Sample C

Sample D

Sample E

Sa mple F

Water samples

Figure 1: Graph of coliform content against water samples Conclusion and recommendation The result of the physical, chemical analysis revealed that the sources of water sampled are fairly good enough for drinking and for other domestic purposes. They provided values within the World Health Organization recommended standards. There is a need to reduce the hardness in samples A, B & C. In addition, the calcium contents of all the sources should be regulated. The bacteriological analysis revealed that only samples D and F are free from faecal or sewage contamination and the remaining samples are hazardous in their present states. Recommendations There is need to educate people on the dangers of drinking contaminated/poor quality water, and they should be taught simple means of improving the quality of water. REFERENCES 1. O.A Adebile, Statistical Method in Research for Applied and Behavioural Sciences. Mactop Publisher, Osogbo, Nigerial, 2001. 2. A.C Okuofo and N.O Echafoma, Bacterial Logical and Physio-chemical Examination of wells in Ahmadu Bello University Zaria, ABU Journal of Applied Sciences, Pg 42-48, Oct, 1990. 3. National Population Commission, Census Results, 2006. 4. A.C Okuofo, International Standard for Drinking water, Unplished Data, Switzerland, 1989. 5. World Health Organisation, International Standard for Drinking water, 1971,1980,1993,and 2006. 6. World Health Oganisation, World Water Day Reports, 2000-2002 7. T.M. Chioma, B.I Ugbeoku and D.O Patrick, Environmental Impact on the quality of Abter from Hand Dug wells in Yola Environs. Leonard Journal of Sciences, January-June Pg 67-76, 2007. 8. J.D. Bernald, Water Supply and Sanitation in Developing Countries, Publication of the Institution of Water engineers and Scientists, London 1983.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria 9. W.J Kaufman and G.T Orlob, Measuring groundwater movement with Radio Active Chemical Tracers, Journal of American Water Works Association Pg 559-572. APPENDIX Samples A, B, C – Wells from Adebayo, Ajilosun, Odo-Ado. Samples D and E – Satchet water produced in Ado-Ekiti. Sample F – Pipe Borne water from the state water corporation.

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497

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

498

(ICERD08086) EVALUATION OF OGUN STATE WATER SUPPLY SCHEME IN ABEOKUTA METROPOLIS Sulaimon D Department of Mechanical Engineering, Olabisi Onabanjo University, Ibogun Campus Adesina A.O Department of Agricultural Engineering, Olabisi Onabanjo University, Ibogun Campus

This work evaluates water supply scheme in Abeokuta metropolis. In this study, questionnaires were distributed to Ogun state water corporation, Abeokuta and a cross section of consumers within the metropolis. Personal interviews were granted and relevant primary data were collected so as to investigate the adequacy and functionality of the water supply scheme in the metropolis. Results indicate that water supply has not been adequate or functional in some parts of the metropolis. The quantity of water supply per day is 63,173.50m3/day to16,454 households that subscribe for water. The current rate of water supplied per household and per capital water supply rate is 900.81 MLD and 90L/capital/day respectively. There is a need to upgrade and expand the distribution network so as to ensure regular water supply and meet up with the ever increasing demand for water on a daily basis.

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499

(ICERD08189) THE USE OF LOCAL MATERIALS IN WATER DISINFECTION

Anyata, B.U. and Mgbemere, V.E. Dept of Civil Engineering, Univ. of Benin, Benin City, Nigeria

The antimicrobial activities of twq plant extracts namely, citrus aurantifolia, (lime juice), and psidium guajava (guava leaf), were investigated using water contaminants namely: Escherichia coli, staphylococcus aureus, proteus vulgaris, and klebsiella spp. The paper disc method was used for this study. From the results of the experiments, the lime juice extract and psidium guajava extract tend to have high antimicrobial activity, since they showed inhibition on all the test organisms used, and their zones of inhibition are high. Gertimycin was used as a standard control. The minimum inhibitory concentration test was carried out on the two test plants, to determine at what concentrations the test plants have an inhibitory effect on the test organisms. The test plants indicate that the active constituents lie more on the residue. Phytochemical analysis was carried out, and the result shows that the active constituents in the psidium guajava extract include alkaloids, tannis, saponins, and phenolic compound. The active constituents in the citrus aurantifolia extract are P-hydronybenzoate, the citric acid and limonene. Keywords: Antimicrobial activities, lime juice, leaf, test plant extracts; residues, inhibitor, phytochemical tests.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

500

(ICERD08191) USE OF HYDRAULIC NETWORK MODEL FOR EVALUATING FIRE FLOW CAPACITY OF A WATER DISTRIBUTION NETWORK O.C. IZINYON(1)AND B.U. ANYATA(2) DEPARTMENT OF CIVIL ENGINEERING, UNIVERSITY OF BENIN, BENIN CITY, NIGERIA. (1) Email: [email protected]; (2) Email: [email protected].

A WaterCAD hydraulic network, model of the existing Ikpoba Hill Benin City water distribution system was constructed and calibrated for steady state simulation studies using the network’s physical, operational and calibration data. The model was then used for available fire flow analysis and system improvement design. Our study reveals that the existing network has available fire flow of O l/s and hence cannot provide needed flow for fire suppression. However, the proposed improved network with increased diameters of existing pipes and which also takes into account expected future growth has available fire flow of between 29.6l/s and 40l/s at the nodes in the network. On the basis of available fire flow at the nodes in the system, hydrant tagging, numbering and colour coding which can effectively increase the fire fighting ability of the fire department can be undertaken. Keywords: Network hydraulic model, fire flow analyses

[ For the detailed document go to page 1459]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

TECHNICAL SESSION 4A: MATERIALS AND PROCESSING IV

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501

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

502

(ICERD08004) MEDIUM OPTIMIZATION FOR SPECTROFLUORIMETRIC DETERMINATION OF HISTAMINE IN HALIEUTIC AND DERIVED PRODUCTS BY USING FLUORESCAMINE AS DERIVITIZER. ADAMOU Rabani1,3, COLY Atanasse2, DOUABALE Stephy Edgard2, SALECK Med Lemine2, IKHIRI Khalid2, TINE Alphonse2 1 University Abdou Moumouni, Niamey, Niger 2 Université Cheikh Anta Diop, Dakar, Senegal 3 Corresponding author - E-mail: [email protected]; Phone: +227 96897981;

Histamine is a product of decomposition caused by the growth of some bacteria in seafood. The absorption of a very low amount causes serious allergies, respiratory disorders, vomiting and diarrhoea [1]. In this study, we propose a simple, reliable and less expensive alternative compared to traditional methods [2]. The optimization of the solvent (acetonitrile) enabled us to increase the sensitivity of our method 15 times compared to solvent traditionally used. The use of tensioactive molecules in acetonitrile increased our method sensitivity more than 70 times and the stability of the analysis signal more than 20 times compared to traditionally solvents. The use of optima obtained conditions (solvents and derivitizer concentration) allowed obtaining linear calibration curves and a limit of detection largely lower (0.5 ppb). Analyses of local market sardine samples give a content of histamine (18 ppm) largely under the international tolerance rate (100 ppm) in halieutic and derived products; that shows the quality of our local market fish. Nevertheless this content challenges the fishmongers to improve their storage conditions.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

503

(ICERD08014) FINE-TUNING OF SURFACE PLASMON RESONANCE IN AU-VO2 NANOPLASMONICS SYNTHESIZED BY RF INVERTED CYLINDRICAL MAGNETRON SPUTTERING J.B. Kana Kana1-2, J.M. Ndjaka2, N.Manyala3, O. Nemraoui4, A.C. Beye5, and M. Maaza1 1Nanoscience and Nanotechnology Laboratories, Materials Research Group, iThemba LABS, P.O.Box 722, Somerset West 7129, South-Africa. 2Dept. of physics, University of Yaounde I, P.O.Box 812 Yaounde –Cameroon. 3Dept of Physics and Electronics, National University of Lesotho, P.O.Box Roma 180, Maseru-Lesotho. 4Dept of Physics, University of Zululand, Private Bag X1001, Kwadlangezwa, South Africa 5African Laser Centre, P.O.Box 395, Pretoria 0001, South Africa.

We prepared gold/ Vanadium dioxide nanocomposites thin films by the rf reactive inverted cylindrical magnetron sputtering (ICMS) for the first time and report their enhanced surface plasmon resonance (SPR) tunable shift reversibility. ICMS has been attracting much attention for its ability for uniform coating of three-dimensional objects and high –rate deposition of dielectric materials. To investigate the optical properties of gold nanoparticles embedded in an active matrix (VO2) composite film was synthesized on corning glass substrates for several substrate temperatures ranging from 4000C to 6000C. The X-ray diffraction results demonstrated that the Au and VO2 were well crystallized. The optical transmission properties were measured from 300nm to 1100nm and the absorption peak due to the surface plasmon resonance (SPR) of Au nanoparticles were observed. Under external temperature stimuli, the tunable reversibility of the SPR shift was observed when the nanocomposites temperature varies from 250C to 900C.The enhancement of this shift of SPR was observed as the substrate temperature increases and it was found that the shift of SPR increased rapidly with increasing substrate temperature but then remained constant at ~60nm for substrate temperature higher than 5000C.The wide hysteresis loop width about 350C of the SPR can be exploited for many technological applications.

Keywords: Nanoplasmonics, Surface plasmon resonance; Vanadium dioxide, Thermochromic; rf inverted cylindrical magnetron sputtering.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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(ICERD 08016) LEACHING OF TRACE METALS FROM TWO DIFFERENT SIZE SOILS A. Y. Abdulfatah1, Dr. A. El-Hamalawi2 and Professor A. D. Wheatley3 (1,2,3) Department of Civil & Building Engineering, Loughborough University, Loughborough LE11 3TU, United Kingdom, Telephone: +44 (0)1509 223206, E-Mail: [email protected] (corresponding), [email protected] & [email protected]

Abstract: Two different size-grained soils were subjected to column experiments with a hydraulic loading representing two years’ rainfall. Leachates were collected and analysed for pH, Electrical Conductivity, Carbon contents, and for nine trace metals, namely; Iron (Fe), Copper (Cu), Chromium (Cr), Nickel (Ni), Lead (Pb), Manganese (Mn), Zinc (Zn), Silica (Si) and Sulphur (S). The analysis was conducted using an inductively coupled plasma (ICP) method of spectrometry. The results show different extractable metal concentrations from the two soil samples. The paper reviews and compares the experimental results with the data from the literature on trace metals. Keywords: Particle size distribution (PSD), Trace metals, Water quality determinants, Column experiment1. Introduction: Changes in soil particle size distribution (PSD) and its hydraulic conductivity can be expected to increase the leaching of trace metals bound in soil. PSD here is defined as the distribution of the weight or volume of solid particles falling into different size ranges. This distribution gives the percentage of the total solids of all sizes in a sample and is one of the most important soil property affecting adsorption and boundary retention. Soils with smaller particle sizes such as clays, possess large surface area, which influences soil-contaminant interactions [1]. Hence, the amount of water or heavy metals adsorption in soil is a function of particle and pore size properties [2]. The conventional way of this analysis is by using sieves of different sizes, and the modern techniques include passage of samples through an electrically charged orifice, e.g. a Mastersizer to measure both size and charge. Heavy metals react and dissolve in soil [3,4]. The reactions produce final chemical product(s) e.g. CdSO4, Pb(CO3)2, NiSO4 and CuCl2. This will affect the solubility of species in water. This is an electrochemical reaction often resulting in a mobilisation of cations into electrolytes [5]. In general, reaction and dissolution involve reversible phase transition from solid to liquid. Adsorption is the accumulation of chemical species uncharged at the interface between the surfaces of soil-solid and soil-solution phases [6]. This process involves the attachment of dissolved species from the soil solution onto the solid surfaces. The process can be reversed when it is referred to as desorption [7]. In other words, adsorption can be defined as a transfer of ions from the soil solution to the solid surfaces [8]. Factors affecting the sorption process are (1) the characteristics of the contaminants e.g. solubility; (2) characteristics of the soil, e.g. mineralogy, permeability, porosity and surface properties; and (3) characteristics of the soil-solution, e.g. pH value, salt and organic contents. 2. Methodology: The aim of this test was to compare the extractable trace metals from two different size-grained soils. There was no standardised leaching test procedure for soil materials [9]. An acid washed glass column of 58 mm diameter and 1.19 m length was set up, firstly with a sample from Loughborough with a grain size range of 0.004 to 0.4 mm silt-sand and secondly with the other sample from a University of Lancaster test site with a grain size range of 0.028 to 0.8 mm sand. For identification purposes, the sample from Loughborough is presented as Lboro soil and the other sample from Lancaster as Lanca soil throughout the experimental graphs. The measured unit weights of the two soil samples were 13.60 kN/m3 for the Loughborough soil and pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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14.03 kN/m3 for the Lancaster soil. The hydraulic conductivity of the Loughborough soil was measured as 3.924 x 10-5 m/s and that of the Lancaster soil was 3.511 x 10-4 m/s. Mastersizer 2000 (Malvern Instruments) was used to analyse the particle size distributions of the two sandy soil samples as shown in Figure 1. This technique of particle size distribution uses laser diffraction system and is capable of measuring wet and dry soil samples. In each of the column experiments equal portions of 6 mm gravel were placed at the bottom of the test columns. The placement of the gravel apart from facilitating drainage it also prevented clogging of the sampling tube by the fine sand particles [10].

Figure 1: Mastersizer 2000 The common leaching solution used in many tests is either distilled water or distilled water with diluted Nitric acid HNO3 in the case of pH dependence tests. In this study, tap water was used as irrigation fluid in the column tests. The column experiments were carried out in the laboratory at room temperature ranging from 17.4 oC to 18.7 oC. The experiments were conducted with a hydraulic loading of 330ml per flush over units of calculated residence time. In each experiment, 10 flushes were used and these volumes corresponded to two year rainfall of Loughborough (the experimental site). Samples were collected at the bottom of the column and analyzed for different trace metals and water quality determinants. The analyses were conducted by using an Inductively Coupled Plasma (ICP) (Thermoelectron model). For the soluble metal analysis, samples from the column were taken, acidified with HNO3 to a pH value less than 2 and preserved in a cold room. 100 ml of the samples were filtered through No. 1-185 mm diameter filter paper before analysis by the ICP. 3. Results and Discussion: The results of trace metal concentrations and other water quality values from the two experimental soil samples are presented in Table 1. The table shows measured concentrations of metals and water quality determinants in the leaching solution (tap water), which was the control solution. These values were corroborated by the local utility (Severn Trent Water Company, UK). In each graph there are 10 points representing an irrigation of two years equivalent rainfall. Metal concentrations are reported in part per million (ppm).

Metals/Other variables Iron Copper Chromium Nickel

Concentration (ppm) 0.0188 0.050 -0.0135 0.0052

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Lead -0.0127 Manganese -0.0005 Zinc 0.025 Silicon I.541 Sulphur 32.0 Total Carbon 34.0 Inorganic Carbon 31.0 Total Organic Carbon 3.0 Table 1: Measured concentrations in tap water Iron content: Soluble iron concentrations of the two samples are shown in Figure 2.

Figure 2: Soluble Iron content The content of iron in the leaching solution was 0.0188 ppm. It can be seen that iron concentrations started with maximum values of 0.35 and 0.57 ppm from Loughborough and Lancaster soils respectively. This was in line with the brown soil character in the two areas. In both cases iron concentrations decreased with each flush to similar values of 0.07 and 0.1 ppm in Lboro and Lanca soils respectively. This was expected as there were no extra sources of the iron external to the soil materials. Throughout the two experiments iron concentrations were higher than a tap water value of 0.02 ppm, indicating iron leaching from the two soils. It is shown by the two curves that the extractable amount of iron from Lanca soil, which has bigger particle sizes was higher than the amount of iron from Lboro soil. This could be related to the soils’ permeability that enhanced more leaching of iron from Lanca soil or its original mineralogy. Copper content: Copper concentrations from the two soil samples are shown in Figure 3. The sensitivity of the ICP machine for Copper was 0.002 ppm. The machine could therefore detect Copper from as low as 0.002 ppm. In this case the Loughborough soil produced higher values of Copper ranging between 0.02 and 0.064 ppm with an average leaching of 0.04 ppm. Copper values from Lancaster soil were between 0.015 and 0.031 ppm with an average of 0.018 ppm. The two average values of 0.04 and 0.018 ppm from the two samples were both below the tap water content of 0.05 ppm. The data indicates three possibility; (1) Copper concentrations fluctuated within the tap water content and there was no leaching of Copper from the two soils (2) the amount of irrigation and the magnitude of flow velocity were insufficient to detach Copper from the soil particles and (3) The soils themselves absorbed Copper ions from the irrigation water as a result of Copper’s high affinity for soil particles.

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Figure 3: Soluble Copper content

Chromium content:

Figure 4: Soluble Chromium content The quantity of Chromium in the leaching solution was 0.002 ppm, lower than the sensitivity of the analysis machine, which was 0.004 ppm. As such the tap water content was regarded as zero. Figure 4 shows soluble Chromium concentrations from the two soil samples. The Loughborough soil leached out traces of Chromium with concentrations up to 0.015 ppm. There was no leaching of Chromium from the Lancaster soil with all values falling as negative.

Nickel content: Nickel content in the tap water was 0.007 ppm and the sensitivity of the ICP machine for Nickel was 0.005 ppm.

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Figure 5: Soluble Nickel content The Nickel curve of the Loughborough soil shows a starting value of 0.055 ppm and this value decreased continuously with each flush. At the end of the experiment, the concentration was 0.013 ppm to approach background level. The Lancaster soil shows the same trend but with lower values than the Loughborough soil. There was an unexpected rise at flush points 6 and 9, which most likely resulted from experimental errors. In general most of the leaching of Nickel was at the first flush. The values tend to normalize with the tap water content towards the end. Experiments on the total Nickel contents would be interesting.

Lead content: Lead content in the leaching solution was 0 ppm and its ICP detection limit was 0.025 ppm. Any concentration below the detection limit is regarded as zero in this paper. It can be seen in Figure 6 that all values of Lead from both tests, apart from one value from the Loughborough soil, appeared as negative. The only positive value of 0.005 ppm was also lower than the detection limit of the measuring machine and thus it was considered as 0 ppm. Although most soils are rich in Lead [9], its good affinity for soil particles coupled with its poor solubility in water makes it difficult to be detached from the soil particles.

Figure 6: Soluble Lead content

Manganese content: As can be seen in Figure 7, the Manganese from Lancaster soil was the highest . The soil was a red brown colour and Manganese is associated with iron but is more soluble. The concentration decreased from 0.5 to 0.15 ppm in the Loughborough soil and from 1.35 to 0.15 ppm in the Lancaster soil. The data in Figure 7 shows that after flush number 3 the concentrations of Manganese normalised around an average value of 0.15 ppm for the rest of the two experiments. This indicates easy leaching of Manganese from the two soil samples, considering its near to zero value in the leaching solution. This was favoured by the good solubility of Manganese in low pH conditions that existed in most of the experiments. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Figure 7: Soluble Manganese content

Zinc content: Zinc is quite soluble and volatile element which is common in most soils and waters. Its content in the leaching solution was 0.025 ppm. Figure 8 shows a range of concentration values of Zinc, from 0.07 to 0.18 ppm in the Loughborough soil and from 0.07 to 0.325 ppm in the Lancaster soil. By relating these values to its tap water content, it would be noted that there was leaching of Zn in the experiments. The rise in concentrations at flush point 6 was most likely due to experimental errors.

Figure 8: Soluble Zinc content

Silica content: The two soil samples were both Sandy Silica soils. The measured concentration of Silica in tap water was 1.54 ppm and its detection limit on the ICP machine was 0.01 ppm. Figure 9 shows Silica values ranging between 2.3 and 3.2 ppm in the Loughborough soil and between 3.7 and 7.5 ppm in the Lancaster soil. The generally greater concentrations of Silica in the Lancaster soil may be relevant to the future adsorption experiments.

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Figure 9: Soluble Silica content Sulphur content: The tap water measured amount of Sulphur was 32 ppm. Figure 10 shows the concentrations of Sulphur from the two soil samples. The Loughborough soil produced high values of Sulphur of up to 70 ppm at the start of the experiment. These values gradually decreased to an average tap water value of 32 ppm. The content of Sulphur in the Lancaster soil was consistent with an average value of 32 ppm, which was equal to the expected tap water content (the soil was at background level). The results indicate that there was no leaching of Sulphur from the Lancaster soil. The high Sulphur value from the Loughborough soil at the start of the experiment indicates that the sample was a Sulphur rich soil. The soil might have absorbed Sulphur from atmosphere during its agricultural cycle.

Figure 10: Soluble Sulphur content

Water Quality Determinants The water quality determinants namely; temperature, pH, conductivity, and organic and inorganic carbon were measured in both experiments. Temperature and pH: Figure 11 shows sample temperatures for the two experiments. The values were the same and thus represented on the same graph. The first temperature reading was 18.7 OC and this reading decreased gradually to 18.2 OC at flush number 5. After this point it then fluctuated between 17.4 and 18.6 OC. These are typical of laboratory temperatures. The cooling may have been a result of evaporation in the column.

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Figure 11: Temperature readings Figure 12 shows pH values in the range of 5.4 to 6.5 in the Loughborough soil and 5.9 to 6.9 in the Lancaster soil. Though the two experiments were conducted at nearly the same temperatures, the Loughborough soil has less alkalinity than the Lancaster soil but the Lancaster soil immediately picks up higher values and this was maintained to the end of the experiment.

Electrical conductivity: Conductivity was recorded as 800 and 1000 ìS/cm for the Loughborough and Lancaster soils at the start of the experiments. After two flushes the values normalised to an average of 500 ìS/cm in the Loughborough soil and 750 ìS/cm in the Lancaster soil. The average values were close to a background (tap water) level of 567 ìS/cm [11], showing the easily soluble salts are flushed out quickly by rain. Carbon content: The values of inorganic carbon from the Loughborough soil was in the range of 1 to 7 ppm. Whereas the Lancaster soil produced values ranging from 15 to 25 ppm. When these values are compared with the tap water inorganic carbon (background) value of approximately 30 ppm, it was noted that there was a gas exchange of CO2 to CO3- taking place in the sand and this may be involved in the alkalinity balance in the Lancaster soil. Total organic carbon contents from the two experiments were between 2 and 11 ppm (with an average of 5) for the Loughborough soil and 1 and 5 ppm (with an average of 3) for the Lancaster soil. The average value of Loughborough soil was slightly above a tap water value of about 3.0 ppm, indicating some traces of organic carbon from the soil. The organic content of both soils was lower than expected.

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4. Conclusions: The following conclusions were drawn from this study:



  

The results of this study indicate that the Lancaster soil with the bigger grain sizes leached out more Iron, Manganese and Silicon concentrations. This could be as a result of the different geochemistry more than PSD. The Loughborough soil with the smaller soil particles produced highest concentrations of Copper, Chromium, Nickel and Sulphur. There were lower pH values in the Loughborough soil, which favoured leaching of Copper and other metals. The pH of the tap water (>6) was higher than natural rain pH of 5.5 and thus more leaching would be expected in reality.

5 Acknowledgements The authors would like to acknowledge the Petroleum Technology Development Fund (PTDF-Nigeria), Bayero University Kano-Nigeria and Loughborough University (UK) for sponsoring this study.

6 References: [1] Yong, NR, Mohamed, AMO & Warkentin, BP 1992, Principles of Contaminant Transport in Soils, Elsevier Science Publishers B.V., the Netherlands. [2] Lu, N & Licos, WJ 2004, Unsaturated soil mechanics, John Wiley & Sons, Inc. New Jersey. [3] Sparks, DL 2003, Environmental Soil Chemistry, Second edition, Elsevier Science, California. [4] Denaix, L, Semlali, RM & Douay, F 2001, Dissolved and colloidal transport of Cd, Pb, and Zn in a silt loam soil affected by atmospheric industrial deposition, Environmental Pollution, Vol. 113, pg. 29-38. [5] Martinez, CE & Motto, HL 2000, Solubility of lead, zinc and copper added to mineral soils, Environmental Pollution, Vol. 107, pg. 153-158. [6] Sparks, DL 2003, Environmental Soil Chemistry, Second edition, Elsevier Science, California. [7] Sharma, HD, & Reddy, KR 2004, Environmental Engineering, John Weily & Sons Inc., New Jersey. [8] McBride, MB 1994, Environmental Chemistry of Soils, Oxford University Press, First edition, New York. [9] Linde, M., Oborn, I. and Gustafsson, J. P. (2007). Effects of Changed Soil Conditions on the Mobility of Trace Metals in Moderate Contaminated Urban Soils. Water Air and Soil Pollution, 183, p69-83. [10] Etchebers, O., Kedziorek, M. A. M. and Bourg, A. C. M. (2007). Soil Water Chemistry as an indicator of the Reproducibility of Artificially Contaminated Soil Mesocosms. Water Air and Soil Pollution, 179, p125-134. [11] Servant Trent Water (12/09/2007) http://www.stwater.co.uk/server.php?postcode=LE11+3TU&btnWaterQualitySubmit=Search

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(ICERD 08032) Current Trends in Laser Technology and Applications: a Literature Review A. B. Niyibizi Department of Physics, University of Nairobi, P.O. Box 30197 00100 Nairobi, KENYA Tel +254 20 444 7552 (Office), +254 724 970311 (Mobile) E-mail: [email protected] Abstract The laser is no longer a “scientific gadget”, but an “industrial or a medical tool” from which an investor expects financial returns. The present presentation will try to give a literature overview of the state of affairs and trends regarding the most important types of industrial and commercial lasers worldwide and their applications. Introduction In textbooks, practical lasers are mainly classified according to the type of active medium and by the range of wavelengths of the emitted radiation. According to the type of active medium, broadly there are: iondoped solid state, gas, liquid or dye and semiconductor lasers. [1-3]. In terms of wavelengths, the spectrum emitted by common types of lasers spreads from about 157 nm in the UV to about 0.1 mm in the far IR. Accordingly, we can distinguish: UV, visible, and IR lasers. Generally, professionals classify lasers into diode, based on semiconductor compounds and non-diode, based on active media other than a semiconductor [4]. Applications of lasers are endless users usually classify lasers as by application, among which the most important are: material processing, medical, telecommunications, optical storage, basic research, instrumentation, control, entertainment, barcode scanning, sensing, laser pumping, military... [4-5]. Here we look at current dynamics of the most important commercial types of lasers in terms of technological improvements and designs, their new applications and how they compete with each other on the market place. The leading commercial and industrial lasers described here are: CO2, Nd-doped solid-state, fibre, ion gas, He-Ne, excimer and diode lasers. Methodology of research We base our research on a series of classical books and authoritative scientific and professional journals and magazines with updated information on different research aspects and technological state-of-the art findings in photonics and optoelectronic industry worldwide We present our findings in the form of a table, where for each type of lasers we give the type of active medium, the wavelength of the emitted radiation , the main applications, the recent trends in technical improvements, the kind of lasers in competition and an approximate average pricing. The average pricing is based on bulk numerical data on the market report for the laser industry provided annually by one of the leading magazines for the photonics and optoelectronics industry: the Laser Focus World for the 2007 year [4-5].

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REVIEW OF MAIN TYPES OF LASERS FROM INDUSTRIAL DYNAMICS POINT OF VIEW 1. CARBON DIOXIDE (CO2) LASERS Table 1 Carbon dioxide lasers TYPE ë APPLICATIONS

Gas molecular

9.3-10.6 ìm. The most powerful line: 10.6 ìm.

Heavy lifter in material processing industry: about 27% of sales of industrial lasers are CO2 Metal processing, mainly steel: auto, aerospace, shipbuilding. Processing of other materials: wood, plastics, paper… Sealed CO2 lasers: surgery, marking

TRENDS

TRENDS

Pumping by RF excitation; slab discharge with folded resonator. Sealed: handheld From the traditional 10.6 to 9.3ìm

In metal Gas flow: 174,541 processing, traditional competitor: Nd-doped lasers at 1.064 µm Sealed: 6,770 and now fibre and diode lasers

AVERAGE UNIT PRICE US $

Observations: The CO2 is an unrivalled source of directed thermal energy in heavy industry: ”it is the only laser in which the available power is higher than needed” [6]. This is due to the existence of more than 200 laser transitions between 9.4 and 10.6 µm, just above the ground state. The remarkable efficiency is boosted further by a fortuitous match between energy of the CO2. upper laser level and an excited level of N2. Electric energy is efficiently absorbed by N2 and by resonance transferred to CO2. The addition of other gases, notably helium and oxygen optimises that efficiency even further. There are two main configurations: gas flow, for systems with power higher than1 kW and sealed for small, self-contained, plug-and-play units. There are also two geometries for electric field [3]: The geometry of a longitudinal gas flow combined with a longitudinal electric field was used in earlier designs for CW operation at low pressure and low powers. Transverse electric field or TEA (Transverse-excited atmospheric) is good for powers higher than 5 kW at high pressures. This configuration allows a small and compact footprint but a lower beam quality and only a pulsed operation mainly; these lasers can be easily Q-switched to generate giant short pulses. New designs use a folded resonator and mainly RF-excited-slab-discharge [6]. Sealed CO2 have an output of 60 to 400 W. There are very small and are used in low-power applications :marking metals and glass, cutting, drilling vias on printed circuit boards and in ceramics, and welding inorganic materials. The ultimate and last design is a hand-held sealed CO2 laser which delivers 400 mW and can be used in basic research, spectroscopy for instance [7-8]. High power outputs at far IR wavelengths pose problems for optics and generally zinc selenide is the standard material for tramsmissive optics while for mirror copper is used. The other challenge in high-power is the excessive heat generated For example a 20-kW system may need 300l/min of cooling water [6]. 2.

Nd: DOPED SOLID STATE LASERS

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Common industrial solid-state lasers are doped with Nd3+ ion and emit primarily at 1.064 ìm but lasers doped with ytterbium ion are being developed. High-power Nd lasers use glass as host material, but because glass is an amorphous material, the beam quality is poor and the low thermal conductivity of glass allows only pulsed operation. Nd:YAG lasers produce a beam of high quality, low divergence and stable output. They can be easily Q-switched. Ultimately, Nd: YAG is still the common solid-state laser in material processing industry.

Table 2. Nd-doped lasers TYPE

Applications

Competition Unit Price

Wavelength ë (nm) Lamp pumped: Nd: glass Nd: YAG

1064

Diode pumped (DPSSLs):

Harmonics: SHG: 532

Nd: YAG: 1064 Nd: YFL: 1053 Nd: YVO4: 1064

TSG: 355 FSG: 266

Metal processing, DPSSL including semiconductor industry, medical, basic research… The same as above plus Fibre, visible and UV Yb-DPSSLs applications: pointers, range finders, direct-toplate printing, image recording, photolithography

40,850

16,000

There two pump systems for Nd-doped lasers: lamp pumping and diode-laser pumping. Lamp pumping is the oldest and now it is used only for high-power systems, but it presents some inconveniences, including the need of high voltage, high temperature, short-life time of the lamp and a complicated firing circuitry. Diode laser pumping takes advantage of the match between the emission line of the GaAlAs diode laser with a strong absorption peak of neodymium at 808 nm. In 1980’s high power reliable diode lasers based on GaAlAs were developed. This development has given rise to diode-pumped solid-state lasers, DPSSLs. For DPSSLs, Nd: YAG is a crystal of choice: it is inexpensive it can be grown in large sizes of high quality. DPSSLs have high wall-plug efficiency. Low-powered DPSSLs are air-cooled and battery powered. There are two diode pumping geometries: radial pumping and end pumping. End pumping is the most used and it comes also in two versions: close pumping [9] and fibre-coupled. New designs use disc geometry to increase the surface-volume ratio to facilitate heat removal. The most preferable field of DPSSLs is in harmonic generation: SHG, TSG, and FHG (second, third and fourth harmonic generation) with possibility of modular design. Nd: YLF and Nd: YVO4 lasers are growing in popularity. They present a high gain, a lower threshold, for example those used in low-powered hand-held pointers. Diode-laser arrays allow SHG (second harmonic generation), THG (third harmonic generation) DPSSLs at prices competitive with ion lasers in visible and with excimer lasers in UV applications, threatening the argon and excimer laser industry [10]. In recent developments, high-power InGaAs diode-laser arrays at 940 nm have led to the use of Ytterbium (Yb) ion instead of Nd-ion. Yb3+- based laser materials: Yb: glass, Yb: YAG can be efficiently diode-laser- pumped in the 900-980 nm range. The broad emission band of the Yb ion allows the production femtosecond -laser pulses by mode-locking. The development of AlGaInP red diode underlies research into pumping of Cr+3- doped crystals (alexandrite, LiCaF) and, Ti: Sapphire lasers. Gallium nitride technology should provide high-power UV diode lasers to pump DPSSLs in the visible without frequency conversion

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3. Fibre lasers Table 3.

Fibre lasers

Type

Ë, nm

Applications

Trends

Competition

Iondoped optical fibre

Depends on the doping ion Yb:1080,1110 Er-1550 Nd: 1060

Same applications as any sold state lasers at the same wavelength: marking, engraving, micromachining, material processing plastic welding/cutting

Higher powers,. More compact Frequency conversion. Ultrafast designs. Use of innovative fibre geometries photonic-crystal fibres [11]

Competition to bulk solid-state Nd:YAG, excimer and CO2 in material processing

Average unit price 29,350

Observations Industrial fibre lasers are relatively newcomers. They were developed from the EDFAs, erbium-doped fibre amplifiers that are used in long-haul fibre-optical communication systems. Fibre geometry presents favourable surface-to volume-core ratio allows effective heat removal, an almost unlimited of active medium: metres of fibre and it is very compact: a long fibre is coiled in a small box. The most popular doping ion is Yb which has a broadband emission centred at 1080 and 1110 nm and can be very effectively pumped by high-power diode lasers emitting in the 900-980 nm range. Yb-fibre lasers have very high efficiency, 60%, when pumped by, diode-laser modules at 940 and 976 nm. Recently, IPG Photonics Corporation, Oxford, MA, has availed a 3kW-commercial ytterbium fibre laser, YLR-3000-SM. This laser emits a single mode at 1075 nm [12] 4. ION GAS LASERS Table 4. Gas ion lasers APPLICATIONS TYPE Argon Krypton

458, 488, 514, 752 568,647

THREATS

Average Unit Price $ US 7,000

TRENDS

ë, nm Material processing, medical, instrumentation, basic research. image recording, pumping of dye and Ti: sapphire lasers…

Air-cooled, Self-Contained plug-and-play designs

DPSSLs, Visible Lasers

Diode

Observations Gas ion lasers, mostly argon lasers were once the most powerful CW lasers operating in the visible: several watts of output power were available and in pulse regime, powers of the order of kW could be obtained. Krypton produces spectral lines ranging across the entire visible spectrum 340-800 nm with the most intense at 647 nm. In some designs, argon and krypton are mixed to produce quasi-white all-lines output. But these lasers suffer of extremely low efficiency and harsh discharge conditions. Most of the systems are water-cooled. This is why there being replaced by a series of other types of lasers: DPSSLs, notably at 532 nm, fibre and directly frequency-doubled diode and GaN diode lasers at 488 nm [13]. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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5. HE-NE LASERS Table 5. He-Ne lasers Type Gas Atomic

Wavelengths, nm 1523 (IR) 632.8 (red), 612 (orange) 594 (yellow) 543 (green)

Applications

Trends

Competition

Average Unit Price

All kind of instrumentation and metrology, holography, interferometry, basic research entertainment, inspection and control, barcode scanning, image recording… Other visible applications: alignment, pointers…

Higher Powers for 632.8 nm (15-30mW), New wavelengths : 594.1, 611.9 543.5

Visible Diode and DPSSLs

400 Higher powers and other wavelengths are more expensive

Observations He-Ne laser was the second laser to be constructed in 1961 at 1.15 µm; and in 1962 at 632.8 nm. This is a unique laser: simple, reliable, convenient source of continuous monochromatic light, with a sharp defined and highly coherent beam, for many laboratory applications. Coherence lengths can attain tens m for particularly highly stabilised versions. It is unrivalled in applications which require high coherence such as holography and interferometry. It is the cheapest non-diode laser.Until now almost 60% of manufactured non-diode units are He-Ne. Its most important drawback is its very low efficiency (< 0.1%) and low power output (typically less than 30 mW). The trends are the production of more powerful red He-Ne and also develop lasers emitting at other wavelengths than the red 6. EXCIMER LASERS Table 6. Excimer lasers Type

ë,nm

Atomic gas XeF 351 XeCl 308 ArF 248 KrF

193

F2

157

APPLICATIONS

TRENDS

THREATS

Semiconductor industry: UV photolithography, fabrication of fibre Bragg gratings, inkjet nozzles, flat-panel displays, FPDs.. Micromachining: metals, glass, quartz, polymers, Medical: LASIK [14] Photochemistry, photobiology

Shorter wavelength for narrower lines in IC < 100 nm: Evolution from XeCl to ArF, then to KrF and F2, Introduction of portable, wallplug, air-cooled versions

Frequency converted DPSSLs 6SG: 177 nm 7SG: 152 nm GaN diode and fibre UV lasers

AVERAGE UNIT PRICE US $ 380,082 One of most expensive in cost and maintenance

Observations Excimer lasers are the most powerful UV lasers. Their design is very similar to that of CO2 lasers. They use high pressure, (p~ 5 atm) with active gas constituting only 1% of the total and buffer gases, notably He and pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Ne taking the rest. An excimer laser can produce pulses with energies ranging from mJ to ½ J with peak power in tens of MW. They are the first choice for UV photolithography and the trend is the use of shorter and shorter wavelengths to get smaller and smaller circuit-board features. Their most important disadvantages: they are very expensive; they have massive size, poor stability, short lifetimes of the tubes. In addition their maintenance is very costly and they are not user friendly. Fibre and DPSSLs with frequency conversion present a real challenge to excimer lasers.

7. DIODE LASERS In the year 2000 in what is known as “Telecom Bubble”, of a total turnover of 8.8 billion dollars for the entire laser industry, the diode lasers counted for 75%. For the year 2007, they counted for 55% of 6.89 bn of the total [5]

(a)

VISIBLE DIODE LASERS

Table 7.

Visible diode lasers

Wavelength

Material

APPLICATIONS

Units

370-490 630-680 670

InGaN Optical storage: HD DVD, Blu-ray Disc at 405 nm AlGaInP Optical Storage: CD-ROM, CD-RW, DVD-ROM Visible applications: pointers, entertainment and GaInP display, alignment. Barcode scanning…

Unit Price

>100,000,000 3.00

(b) NEAR INFRARED DIODE LASERS Table 8.

Near-infrared diode lasers

Wave Material Length, nm 785 AlGaAs

808

980

InGaAs on GaAs

Applications

Units >300,000,000

Unit Price 2.00

Solid-state laser pumping (DPSSLs)

>100,000

1,200

EDFA Pumping (stacks and arrays), medical, material processing

>300,000

Optical storage: audio CD, CD-ROM, DVD, image recording. Sensing

(c) Telecommunication Diode Lasers Table 9.

Telecommunication diode lasers

WAVE LENGTH, nm 980

MATERIAL

InGaAs on GaAs

1310

InGaAsP on InP

APPLICATIONS

Telecommunications: EDFA pumping Telecommunications:

UNITS

Market share

Unit Price

6,000,000

65%

500.00

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria 1550

substrate

519

transmitters

Observations A working GaAs junction diode laser in 1963, but it was: cryogenic, pulsed and its lifetime was only a few hours, due to too high threshold current densities. Double heterojunction GaAlAs lasers were availed in 1980s; they could operate at room temperature and in CW at 785 nm. Their main application was in CD players that revolutionized the music and movie industry. Until now they constitute more than 86% of units produced and 21% of sales of all diode lasers; they are mainly used in optical storage (audio CD, CD-ROM drives, DVD...). Optical fibre communication systems are based on diode lasers as transmitters at 1310 and 1550 nm and power diode laser arrays and stacks at 980 nm are used for pumping of erbium-doped fibre amplifiers (EDFA) that are used for regeneration of optical signals at 1550 nm in long-haul systems. These arrays and stacks are finding applications in medical and material processing. When frequency converted they can emit in the blue region efficiently replacing argon-ion lasers in some applications Power lasers and stacks at 808 nm are mainly used for pumping of Nd-based DPSSLs. In the visible part of the spectrum, apart from being used in optical storage, red diode lasers are an effective replacement of once ubiquitous He-Ne for most visible applications.

Trends The most important event in laser industry in recent years was the development of the GaN true blue diode laser at 405 nm, which will revolutionise the optical storage in increasing drastically the storage capacity of CD-ROM and DVD discs and in allowing the development of UV diode lasers [15]. In the visible, the development of AlGaInP red diodes is expected to ease optical pumping of DPSSLs emitting in the visible without the need of frequency conversion. In the other end of telecom wavelengths the emphasis in research is the development of tunable diode lasers which will facilitate the wavelength division multiplexing, WDM, in all systems of optical fibre communication 4. Conclusion In the one hand, lasers are well established industrial, medical and scientific tools with endless applications. In the other hand, it is a very dynamic technology and its applications keep rising. The most obvious trend is the use of simpler, safer, more compact and more economical designs (e,g. the development of diode and fibre lasers in applications once dominated by bulk CO2 ,ion gas and solid-state lasers.) The other obvious trend is the push into shorter and shorter wavelengths into deep UV, be for the traditional excimer or new comers DPSSLs, fibre and diode lasers. In over all on the general satisfaction of the user, the overall trend is that all new designs are more compact and rugged, better performing, more cost effective and more userfriendly. 5. Acknowledgements This work was logistically supported by the Department of Physics, the School of Physical Sciences and the College of Biological and physical Sciences, University of Nairobi. I thank also the African Network of Scientific and Technological Institutions for its financial support.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

6. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15]

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References J. Wilson and J.F.B. Hawkes, Optoelectronics, an Introduction, 2nd Ed., PHI, New Delhi, 2000 J. Wilson and J.F.B. Hawkes, Lasers, Principles and Applications, Prentice Hall, N.Y. 1987 J. Hecht, The laser guidebook, 2nd En. TAB Books, Blue Ridge summit, Pa. 1992 K.Kincade and St. Anderson, Laser market place. Part I: Non-diode lasers, Laser Focus World (LFW), (2008) Vol. 44, No 1, p. 74-96 R.V. Steele., Laser market place. Part II: Diode lasers, LFW (2008) Vol. 44, No 2 S. J. Mattthews, Heavy lifting (LFW), (2001) Vol.37, No 10, 89-94 Y. Zhang and al, Miniaturized CO2 lasers show that size matters, LFW (2004) Vol.40 No 9, p.89-93 J. Law and C. McBeth- Schomer, Sealed CO2 lasers find new applications, LFW, (2002) Vol.38, N0 5, p. 85-89 Melles-Griot, The Practical application of light (catalogue 1999), Irvine, CA, p.41.5 J.Flores et al, Solid-state lasers challenge excimers in IC processing, 2002, Vol 38, No 7, p.85-8 J. Hecht, Fiber lasers take off in diverse directions LFW (2004), Vol.40, No 12, p. 81-86 YLR-3000-SM, LFW (2008), Vol. 44, No 1, p. 38 L. Marshall, Many variant lasers compete in the blue, LFW, 2004, Vol. 40, N0 40, p.79-83 H. Frowein and H.Schillinger, Compact excimers fit into industrial niches, Optoelectronics World, Suppl. to LFW (2002). Vol.38, No7, S9-S11 R.V. Steele, Laser Marketplace 2004.Part II: diode lasers, LFW (2004), Vol.40, No2, p.71-82

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(ICERD08033) GLASS MANUFACTURING: MODELING GLASS FLOW IN PRESSING PROCESS

Tsegaye G. Ayele 1 Glass is a very useful material. It has a variety of applications in packaging, optics, insulation, etc. Raw material used for glass production is silicon dioxide i.e., ordinary sand available in abundance. In industries glass is produced at very high temperatures. At this temperature it can be considered as a highly viscous Incompressible Newtonian Fluid. In the production of glass two phases are very important: the pressing process and the blowing process. This study deals with the modeling of flow of glass during the pressing process. This flow is modeled by using Navier - Stokes equations and then some simplifications are applied based on Slender Geometry Approximations. The main emphasis here is on the modeling of the time evolution of free boundary of glass during pressing.

Keywords: Mathematical Modeling, Navier - Stokes equations, Incompressible Newtonian Fluid, Pressing Process, Slender Geometry Approximations. 1Department of Mathematics, Addis Ababa University 1

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(ICERD 08036) Survey of the Development in Automotive Materials: Peugeot Model as a Case Study B. Kareem (1), S.B. Adejuyigbe (2), S.P. Ayodeji (3) Department of Mechanical Engineering, Federal University of Technology, Akure, Nigeria. Phone: +2348033737251, Email: [email protected], [email protected] (2,3) Department of Mechanical Engineering, Federal University of Technology, Akure, Nigeria. (1)

Abstract: Automobiles, in the 1970 or less, were built from heavy and easily corroded materials. In the recent past new materials of lightweights have emerged from research and development efforts which, have contributed immensely to the improvement in performance of the old model vehicles in term of material stiffness, fuel economy and cost of manufacture. The trend of modern material developments is noticeable globally but the content of such materials in automotive components building is unclear. In this study, survey was conducted and data on the level of utilization of new and emerging materials in Peugeot models’ components building were collected. The information was collected from two major Peugeot assembly plants located in Kaduna and Abuja of Nigeria. The data were analysed statistically based on frequency counts and weighted averages. The results of the analyses showed that engine block, gearbox, bumper, bonnet, doors and chassis of Peugeot models were critical parts that witnessed material developments in different degrees over the years. Keywords: Peugeot models’ parts, Lightweight materials, Performance, Survey. 1. Introduction The automobile was not invented in a single day by a single invention. The history of the automobile industry reflects on evolution that took place worldwide. Starting with the theoretical plans for a motor vehicle that had been drawn up by both Leonardo Da vinci and Isaac Newton; several Italians recorded designs for wind-driven vehicles the first was Guido Da Vegenano in 1335. The vehicles got bigger and heavier and more powerful and as such they were eventually capable of pulling a train of many cars filled with freight and passengers. Development in automobile is made possible with the advent of new and emerging materials which are the products of continuing efforts of past researchers in the field of material science. Materials have evolved with mankind since the dawn of civilization. Many materials are found in nature or grown but the first material to be made by combining different substances was glass in ancient Egypt. With the progress of time, stone followed so also was bronze. Iron marked the material that shaped the early ages of civilization. The number of materials in service of man has increased slowly over the years and even by the early twentieth century, timber; concrete, steel and its alloys were still the primary materials use by engineers. This was because the properties of these materials were sufficient to meet the requirements of the traditional engineering structures and machines. With the increasing demand for higher services temperatures, lighter structures and more reliable components better materials had to be found. As a result, many ferrous and non-ferrous alloys, plastics, ceramics and composite materials were introduced and the modern engineers have a great and diverse range of materials at their disposal. In the recent time, the need for automobile light- weighting has been of prior importance in the automotive industry. With the development of automobile technology, more and more light – weight materials are applied to automobile body especially glass fibre thermoplastic material (GMT). This study primarily x-rayed the improvements achieved so far in the world of automotive parts as a result of continuing advancement in material development. Therefore, this research aimed at monitoring the development in automotive materials as a vehicle to new spare parts/components development for Peugeot pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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cars. The study would assist the Peugeot users to be well acquitted with new trends of material utilised in the manufacture of Peugeot and the parts/components of it that witnessed such change. Peugeot is a major French car, brand, part of Peugeot Citroen with its headquarters in Sochaux, France. Peugeot is the second largest automaker in Europe, behind Volkswagen. The first Peugeot automobile (a three-wheeled steampowered car) was produced in 1889, in collaboration with Leon Serpolhet steam powered was heavy and bulky and required lengthy preparation before running, so it was soon abandoned in favour of the petrolfuelled internal combustion engine. In 1890 a Daimler engine was manufactured with four wheels [1]. Further cars manufacturing followed, twenty-nine being built in 1892. These early models were given Type numbers with the Type 12, for example, dating from 1895 Peugeot became the first manufactured car with fitted rubber tyres and petrol-powered. In 1896, the first Peugeot engines built and fitted to the Type 15 without relying on Daimler. Further improvements followed such as changing of engine position from the underneath to the front under the bonnet (Type 48) and the steering wheel was adopted on the Type 36 model. In recent time Peugeot automobiles were classified into: executive type and family type. This research concentrated on both types out of other several types in existence. The types considered – executive and family size was broadly grouped into three classes with respect to the car body type or style: sedan or saloon body styles; station wagon or estate body styles; and coupe body style. In this research more emphasis was laid on the recent models of Peugeot including Peugeot 505, 406, 607, 407, and 307. The Peugeot 505 was an executive car produced by the French manufacturer from 1979 to 1992 in Sochaux, France. It was also manufactured outside France, for example, in Argentina by Sevel from 1981 to 1995, and Nigeria (by Peugeot Automobile of Nigeria, PAN Nig Ltd). Peugeot 505 was the replacement for the Peugeot 504 (although European production of that car continued until 1983, and it is still sold in developing markets today). It was available in sedan/saloon and station wagon/estate body styles, with the family estate model featuring 8-seats [1]. The car was rear wheeled drive, with longitudinal mounted engines (Fig. 1). The Peugeot 406 (Fig. 2) was a large family car from the French automaker from 1995 to 2004 and it was available in sedan, station wagon and coupe body styles with a choice of gasoline or turbodiesel engines. The 406 replaced the Peugeot 405 in Peugeot line up, and was itself replaced by the Peugeot 407. The 607 was launched in 1999, to replace the 605. It used its predecessor’s chassis but had an all-new, more modern exterior design. The engine range (2.2 and 3.0 petrol, and 2.2 diesel) was completely new. Equipment levels were so high, with all models getting air conditioning, CD player, electronic windows, airbags, anti-lock braking system and central locking device. The Peugeot 307 (Fig. 4) was presented as the 307 promethee prototype at the 2000 mondial de I’ Automobile. The production of hatch-back versions were introduced to the European markets in 2001 as a successor to the Peugeot 306. The Peugeot 407 (Fig. 5) is a large family car produced since 2004. It is available in saloon, coupe and estate variants, with both diesel and petrol engines. The petrol engines range from 1.8 to 3.0 – litres, and diesels were existed in 1.6, 2.0, 2.2 and 2.7 – litres. The world of automobiles has witnessed tremendous innovations to keep pace with the demand of the jet age. Some of these striking additions to the automobile “arena” are development of V6 engines, which has reduced greatly the space allowed for engines in modern cars with attendant increased power output.

Figure 1. A Peugeot 505 car pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Figure 2. A Peugeot 406 car

Figure 3: A Peugeot 607 car

Figure 4: A Peugeot 307 car

Figure 5: A Peugeot 407 car In compliance with increasing environmental consciousness and the demand for automobile safety, the structure of automobile bodies and the materials used are changing. In particular, vehicle weight reduction has become a key technology in the automobile industry today. As a result, steel products for automobiles have rapidly evolved. Consequently, high strength steel sheet (HSSS) has found wider application in autobodies, drive systems, suspension parts, and forming process technologies for high strength steels [2]. In recent years, in order to increase automotive fuel mileage through the reduction of automotive bodyweight and the performance of safety in impacts, ultra high-strength steel sheet grade have been increasingly applied to automobile body parts. This new invention has few mechanical properties that improved automobile produce, and found its use in automotive seats. Due to improvements in the homogeneity of the microstructure, the developed steel sheets have much better bending for mobility [3]. In other to improve fuel economy through car body weight reduction, 590MPa grade, low YP type, hot dip galvannealed steel has been developed. This steel has the same deep draw ability and stretch formability as pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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440MPa steel, combined with stable high tension strength spot welded joint (achieved through lower carbon levels and other alloying elements). Crash test results suggested that it is possible to replace conventional 440MPa steel with new thinner 590MPa steels designed for maximum load or energy absorption [4]. In response to a growing demand for lighter, safer automobile bodies, the importance of high strength steel sheets with high formability has become significant. Although conventional residual ϻ -steel sheet is known for its excellent significant high properties among high strength steel sheets, the stretch flange ability is not sufficient for automotive parts forming. Kobe steel company (a Japanese company) developed a new residual ϻ -steel sheet with excellent elongation and high stretch flange ability especially, the newly developed residual ϻ -steel sheet controlled residual ϻ -morphology to latre-type through the application of the hot-cal process [5]. High strength hot rolled steel sheets have been applied increasingly in vehicle chassis today. The void creation morphology of bainite-ferrite, bainite and ferrite pearlite steel after stretch flange formation has been investigated. A baintic-ferrite single phase microstructure with a 1.0 atomic ratio of TI by C was proposed to obtain excellent high stretch flange formability [6]. Micro alloyed steels have been developed and put into practical use to simplify the manufacturing process of automobile parts and at the same time reduce manufacturing costs. In particular, high strength micro alloyed steels have been applied to reduce the automobile weight. Micro alloyed steels are known for their high strength and high toughness and hence find more application in automobile production [7]. Environmental improvement and safety are very important in the automotive industry and they sometimes result in increased car body weight. However, fuel efficient lighter cars are increasingly in demand. Aluminium alloys are widely used to reduce car body weight. This has found wide application in automotive parts in countries like Japan, Europe and the USA [8]. As a result of light weight property aluminium alloys are used for production of many parts of automobile such as suspension parts, including upper and lower arms and knuckles. The high deformability of aluminium forged parts is also highly suitable for maximum safety [9]. Recently, aluminium alloy extrusion has met with high interest as an effective material for sophisticated cross section profiles having well-controlled thickness allocations [6]. Such parts cannot be made effectively with steel. Newly developed aluminium alloy extrusion parts for anti-collision parts in automotive structures are introduced. Such parts, which include bumper beams, door beams, crash-boxes, sub-frames, etc; all require highly controlled energy absorption characteristics for collision situations. Majority of materials used in interior automotive designs are basically composites. Fibres find the most usage of the composites used in automotive industries. Fibres are widely used because they satisfy increasingly stringent environmental criteria. Much less energy is used in growing, harvesting and preparing natural fibres than in producing glass fibres. The use of natural fibres can minimize pollution and thereby making it environmentally friendly. The environmental impact that remained can be reduced by choosing crops and farming methods that economise on fuel, fertilizer and pesticide, together with efficient extraction and treatment systems. Natural fibres emit less CO2 when they break down than is absorbed during plant growth. They are non-irritating and non-abrasive, and do not blunt manufacturing tools or processing equipment [10]. Fibres for higher grade applications require a surface modification treatment such as acetylization, to enhance adhesion with the thermoplastic. Alternatively, if the resin is the widely favoured, fibres can be modified with Maleic Anhydride- treated polypropylene molecules (MAPP). Even a tiny percentage of MAPP in water greatly strengthens the resulting composite. NFRPs (Natural fibre reinforced Plastics) are already well established in Europe, which is ahead of North America in the development and adoption of bicomposites. So far, the disadvantages of natural fibre composites have prevented their application structurally. As far back as 1935, researchers hoping to replace steel in automobile bodies with paper wood chips, or other natural fibre reinforced phenolic resin materials found that these composites were not strong enough. The German Trabant car utilizing such materials ultimately proved unsuccessful. The impact strength of NFRPs is particularly poor, as is their fire resistance. Unmodified fibre are easily damaged and weakened during handling or processing. In the move towards biocomposites, the greatest attention has been paid to fibres since they contribute most of composite’s stiffness and strength [11-13]. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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2. Methodology Information was gathered through the use of questionnaire. This detailed on the advancement in material selection for automotive (Peugeot model) parts to achieve various purpose such as light weighting, fuel economy and speed enhancement. The data were collected from Abuja, Akure and Kaduna all located in Nigeria. Information on improvements in Peugeot models based on material developments were obtained from the responses to questionnaires administered. The data collected were analysed using statistical method based on weighted average. The questionnaires were issued to Peugeot manufacturers, technicians, vehicle users and spare parts dealers.

3. Results and Discussion From the returned questionnaires, the following data was gathered as shown in Table 1. The results of the statistical analyses in percentage (weighted averages) are presented in Table 2. From the data, only engine block, gear box, bumper, bonnet, doors and chassis of Peugeot models were being affected by material development. Table 1. Trends in Peugeot materials and parts Peugeot- 504 505 405 model (1970) (1979) (1995) &year/

406 (2000)

607 (2002)

407 (2006)

307 (2006)

Alumini um Alloy Alumini um Fibre

Alumin ium Alloy Alumin ium Fibre

Aluminiu m Alloy Aluminiu m Fibre

Alumini um Alloy Alumini um Fibre

Aluminiu m Alloy Aluminiu m Fibre

H.S.S.S

H.S.S.S H.S.S.S

H.S.S.S

H.S.S.S

H.S.S.S

H.S.S.S

H.S.S.S H.S.S.S

H.S.S.S

H.S.S.S

H.S.S.S

H.S.S.S

H.S.S.S H.S.S.S

H.S.S.S

H.S.S.S

Material and parts Engine block

Cast Iron

Cast Iron

Gear box

Alum.

Alum.

Bumper

Stainless steel Mild steel Mild steel Mild steel

Stainles s steel H.S.S.S

Bonnet Doors Chassis

Table 2. Percentage weighted average of materials 504 505 405 406 607 407 307 Peugeot model/part s Engine 28.6% 71.4% block Cost Iron Aluminium Alloy Gear box 100% Aluminium Bumper 28.6% 71.4% Fibre Stainless steel Bonnet 14.3% 85.7% Mild steel H. S. S.S = High Strength Steel Sheets Doors 14.3% 85.7% pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Mild steel H. S. S.S = High Strength Steel Sheets Chassis 14.3% 85.7% Mild steel H. S. S.S = High Strength Steel Sheets H.S.S.S – High strength steel sheets. The results of the analysis of the data are spelt out as follow: Engine block:- From the study it was discovered that there has been a graduation in materials used in engine block manufacture. The results showed that the early Peugeot models like Peugeot 504 and Peugeot 505 had cast iron as engine blocks while cast iron has been duly replaced in newer models of Peugeot from 405 to the latest ones like the 407 and 307. The use of cast iron for engine block manufacture was only 28.6% stationary while Aluminium alloy which was introduced later was 71.4%. Gear box:- Table 2 shows gear box production in Peugeot models has remained consistent with the use of Aluminium alloy as the major component; therefore nearly 100% of gear box manufactured in Peugeot models from 1970s till the 2000s has been largely Aluminium alloy. Bumper:- This anti-collision part of Peugeot cars has witnessed advancement from stainless steel (in 504 and 505) to fibre material (in 405, 406, 407 and 307). Table 2 ascertained that 28.6% of time bumper made of stainless steel were used and the larger percentage of the time (71.4%) fibre material was introduced. Bonnet:- Bonnets were been made of mild steel in shorter period of about 14.3% and the reminder 85.7% went to newly developed material, H.S.S.S. This showed a progressive trend in material development from mild steel to high strength steel sheets (H.S.S.S.) sheet components. Chassis:- Owing to the need for vehicle durability, enhanced safety and improved vehicle comfort, chassis production in Peugeot has witnessed replacement of the conventional mild steel with H.S.S.S. and it has consolidated a gained of 85.7% composition of chassis manufacture between 1970 and 2006. The continuing improvement in vehicle parts manufacture has brought about enhanced vehicle production in terms of safety, ergonomics and durability.

4. Conclusions This report has extensively reviewed and analysed statistically the material development in the automotive industry especially Peugeot models such as Peugeot 504, 505, 405, 406, 407, 607 and 307. From the review of material composition in Peugeot manufacture, it was clearly shown that the drives towards light weighting and fuel economy are one of the major factors for material replacement and/or enhancement in automobile production without compromising safety. Peugeot models have been able to actualise these objectives by the use of forged steel in their suspension systems to give high performance; also Peugeot uses high strength steels enhanced with extrusive anti-corrosion strategies. About 75% of all sheets materials in Peugeot cars are either electro-zinc plated or galvanised. Finally, the interior décor of Peugeot models has been improved with the use of fibre to give a smooth and elegant interior. However, Peugeot Automobile Nigeria (PAN) should be given a face lift to improve on local production of materials or parts that would be adaptable to the Nigerian environment and at the same time globally accepted.

5. Acknowledgement The author acknowledges Balogun Joseph kehinde, a student in the Department of Mechanical Engineering, Federal University of Technology, Akure ((FUTA), Nigeria, for his assistance in the conduct of questionnaire.

6. References [1] K. Budinski, “Engineering properties and selection”, Peston publishing, 2nd Edition, 1983. [2] Yukihisa, “Latest trends in steel products for Automobiles”, http://www.webwombat.com, 2007. [3] Masamicthis and Masato, “High strength micro alloyed steels”, http://www.autospeed.com/cms, 2007. [4] R.A. Lindberg, “Production of automobile Materials”, Edward Arnold, U.S.A. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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[5] Tadashi, Anti-collision extension parts made of Automobile”, www. autospeed.com/cms, 2007 [6] J. Corum, and M. Ruggles, Automotive Technology Development, 11,. 123(1968) [7] Takashi, Aluminium alloy sheet for automotive body pane,. http://www.wikipedia.org/automobile/peugeot, 2006. [8] C.M. Taylor, Application of composites in automotive structural, 1997. [9] Atsumi and Kouji, Aluminium alloy forging for automotive suspension parts http://www.peugeot.com, 2005. [10] S.B. Chopra, “Dictionary of Mechanical Engineering”, Ammol Publication, 1st Edition London, 1989. [11] L. Garel, Motor Industry. Microsoft Encarta Premium, 2004 http://www.cwn.org.uk/motoring/peugeot [12] J. Karger-kocsis, Mechanics of composite materials, 20(1), 1994. [13] W. Bolton, “Production of Technology”, Heinemann Professional Publishing company U.S.A., 1989.

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(ICERD 08109) A COMPARATIVE ANALYSIS OF PHOSPHATE AND ZEOLITE-BASED LAUNDRY DETERGENTS M.D. YAHAYA1, AND C.A.TAKAYA2 1

Department of Chemical Engineering, Federal University of Technology,Minna Niger state 08032854148 [email protected] 2 Department of Chemical Engineering, Federal University of Technology, Minna Niger state. 08063451303 [email protected]. ABSTRACT A comparison of two brands of phosphate and zeolite-based laundry detergents each was made by evaluating their soil removal, soil anti-redeposition and calcium/magnesium ion complexation properties under varying conditions of water temperature and hardness. Particulate, protein and oily/particulate soils were employed in an effort to simulate realistic soil types, and the percent cleaning efficiency was determined by light measurements. It was found that zeolite-based detergents were capable of cleaning particulate and protein soil with a greater efficiency of 8.62 percent, but ranked lower than phosphate-based detergents in preventing soil redeposition on fabrics by a marginal difference of approximately 0.16 percent. Both detergent types had similar cleaning efficiencies at different levels of water hardness; ranging from 60.34 to 64.66 percent in mg/L Calcium Carbonate equivalent water. Considering the overall results obtained, it was concluded that zeolite-based laundry detergents were a suitable alternative to the less environmentally safe phosphate-based detergents. Introduction During the 1970s and 1980s however, there was concern that the use of detergents containing sodium tripolyphosphate were heavily contributing to the problems of eutrophication. As a consequence, there was a move towards non-phosphate or phosphate-free detergents. This resulted in a large increase in the use of zeolite-based detergents, together with its associated co-builders from the mid-1980s to the mid-1990s in the United States of America, Japan, and some European Union (EU) member states [1]. Eutrophication is the process of nutrient enrichment, resulting from the increased input of elements such as phosphates, nitrates, nitrites and ammonium ions obtained from soil and rocks into lakes, rivers and other water bodies [2]. This stimulates the growth of algae and rooted aquatic plants so that fish and other animals may flourish under optimal conditions. A continuation of this natural process leads to the formation of marshes and bogs. The activities of man have greatly increased the input of nutrient-rich materials into water bodies through such discharges as treated or untreated sewage, crop fertilizers and phosphate-based detergents. Consequently, the number of algae and other green plants grow uncontrollably to form large dense masses referred to as “blooms” [2] which lead to oxygen depletion on their subsequent death and decomposition by bacteria. The greatly reduced level of oxygen is inconducive for aquatic life. Excessive growth of algae and rooted aquatic plants also prevent water movement, and this causes retardation of dissolved oxygen replenishment. Most aquatic animals cannot survive under these conditions of advanced eutrophication. Detergent phosphate contributes to about 40 per cent of soluble (bio-available) phosphorus [3]. The key benefit associated with moving from phosphate to zeolite-based detergents therefore, is a major reduction of the phosphorus load to the environment which, in turn, will reduce problems of eutrophication. In qualitative terms, the greatest benefits would accrue in countries like Nigeria, which have a high phosphate detergent use and a very low provision of tertiary treatment, resulting in significant phosphorus loads being discharged directly to rivers, lakes and seas. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Aims and Objectives The purpose of this research project is aimed at ascertaining that zeolite-based detergents are indeed a better alternative to phosphate detergents, which are commonly used in Nigeria but have been found to be a major contributor to eutrophication. The evaluation of the cleaning efficiencies of zeolite-based detergents in comparison with phosphatebased detergents is achieved by varying such parameters as water temperature and hardness. Realistic soil/stain combinations are employed in an effort to simulate typical wash loads encountered by consumers. Both detergents’ soil removal, soil anti-redeposition and calcium and magnesium ion complexation properties are then determined. Experimental Procedure Qualitative Analysis of the Samples Qualitative analyses are confirmatory tests carried out on each sample of detergent to determine certain parameters which indicate their quality. Four detergent brands’ cleaning performances were evaluated, two of the brands were zeolite-based and the other two were phosphate-based and were identified as follows: 1. Zeolite-Based: Persil Original Non-Biological Powder (A) Persil Original Biological Powder (B) 2. Phosphate-Based: Omo Multi-Active Washing Powder (C) Ariel Gold Powder (D) For the purpose of these tests, terrycloth fabrics, (pile fabrics made of cotton with uncut loops on both sides) were employed as swatches. Soil Removal Test [4] The ability of a detergent to loosen and remove soil with the aid of wash action is as a result of its hydrophilic and hydrophobic portions. The hydrophobic ends attach themselves to the soil particles present in or on the fabrics being washed, while the hydrophilic ends are attracted to the water. The surfactant molecules surround the soil particles, break them up and force them away from the fabric surface, then suspend the soil particles in the wash water.

This test is carried out to evaluate the detergents’ abilities to neutralize different types of soil. In an effort to create realistic soil combinations encountered in a consumer's wash load, soils were selected from three classes: 1. 2. 3.

Particulate soil Proteinaceous soil Oily/Particulate soil

Procedure The light incident on the surfaces of forty eight (48) white, unwashed and labelled terry cloth fabrics were determined by individually placing the four-by-three inch (4"x3") fabrics on the white plaque plate of a Light Meter (AVO SM4 model), having an initial light intensity of 130 lux light incident on the plate. The values were noted. The fabrics were weighed individually, and the results were also noted. A 50 percent slurry (in water) of Bentonite clay to serve as particulate soil, and a mixture of engine oil and charcoal, known as EMPA 101, (so-called by a Swiss Federal laboratory for material testing and pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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research), was employed as the oily/particulate soil. Fresh bovine (cow) blood was employed as the proteinaceous soil. 0.150 grams of the 50 weight percent Bentonite clay was applied to 16 of the 48 terrycloth fabrics inside a 2” diameter circle using a spoon; 16 were soiled with approximately 0.150 grams of bovine blood, and the remaining 16 were soiled with an equal amount of EMPA 101. The swatches were air-dried overnight. The light incident on each swatch was measured subsequently, and the values were noted.1.55 grams of the first of the four detergent brands to be evaluated, namely Persil Original Non-Biological Powder, (A), was measured on the electronic weighing balance. (This quantity chosen was comparable with the quantity commonly employed during hand laundering). 180 parts per million (mg per litre) of Calcium Carbonate (CaCO3) equivalent hard water in a ratio of 3:2 Ca/Mg ions was prepared by the addition of about 140.140 mg/L Calcium Carbonate salt (CaCO3) and 379.450 mg/L of Magnesium Sulphate (Epsom) salt, (MgSO4∙7H20) to tap water having 50 mg/L CaCO3 equivalent hard water. The hardness of the water was ascertained by titrating 100 mls of the prepared water with 0.01M Ethylene Diamine Tetra acetic Acid (EDTA). 50 litres of the water were thus prepared using 7,007.00 mg/L and 18,972.50 mg/L Calcium carbonate and Magnesium sulphate salts respectively. One litre of this water was transferred to a 2000 ml (2L) capacity beaker. Two clay-soiled swatches were introduced into the beaker along with the detergent to be tested, and the contents of the beaker were agitated in an electronic stirrer at seven (7) revolutions per minute for ten minutes. The agitation was carried out at 30 C, the temperature commonly employed for hand laundering. After ten minutes the two swatches were separated from the wash water and introduced into 400 ml water having the same degree of hardness (180 mg/L CaCO3 equivalent hard water). The swatches were rinsed for 5 minutes at 4 revolutions per minute and 30 C. The rinsed swatches were air-dried, and the light incident on both swatches were obtained by placing them individually on the white plaque plate of the light meter. An average of the results obtained was computed and noted. Two blood-stained were introduced into one litre of 180 mg/L hard water along with 1.55 grams of detergent A, and washed in the same conditions as the claysoiled swatches. The rinse cycle followed the same procedure as the former. The average illuminance of the swatches was computed and noted.Two EMPA 101-soiled swatches were subsequently introduced to a litre of 180 mg/L hard water, and the same wash-rinse-air dry procedure was followed, after which the average illuminance was also computed and noted. This procedure was repeated for the three other detergents to be tested, earlier identified as B, C and D. This entire test procedure was carried out on the three other detergent types (B, C and D) at an elevated temperature of 55 C. A regulated hotplate adjusted to a constant temperature of about 170 C served as the heat source. All average illuminance values were noted accordingly.

Detergent Perfomance in Varying Degrees of Water Harness [5] The hardness salts in water act in such a way as to reduce surfactant (that is, detergent) performance. Builders such as phosphates and zeolites have to be included in products to provide the optimum conditions in the wash water for synthetic surfactants and other active ingredients to do their job, and builders are basically water softeners which soften the wash water by extracting and binding the calcium and magnesium ions. In effect the availability of these ions is removed from the wash-water solution, so the “hardness” of the wash-water is reduced. This test is designed to evaluate the effectiveness of the selected detergents at varying degrees of water hardness. Procedure The light incident on 16 white, unwashed and labelled terry cloth fabrics were determined by placing the four-by-three inch (4"x3") fabrics on the white plaque plate of a Light Meter (AVO SM4 model), having one hundred and thirty (130) lux light incident on the plate. The values were noted. The fabrics were weighed individually, and the results were noted. The fabrics were each soiled with approximately 0.150 grams of Bentonite clay. 1.55 grams of zeolite detergent (A), was measured on the electronic weighing pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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balance. Approximately four hundred (400) parts per million (mg/L) of Calcium Carbonate hard water in a ratio of 3:2 Ca/Mg ions was prepared by the addition of about 1344.84 mg/L Calcium Carbonate salt and 3639.00 mg/L of Magnesium Sulphate salt to 50 mg/L tap water. The hardness of the water was ascertained by titrating 100 mls of the prepared water with 0.01M Ethylene Diamine Tetra acetic Acid (EDTA). Four (4) litres of the water were thus prepared using 5,379.20 mg/L and 14,556 mg/L Calcium carbonate and Magnesium sulphate salts respectively. One litre of this water was transferred to a 2000 ml (2L) capacity beaker. Two clay-soiled swatches were introduced into beaker along with the detergent to be tested, and the contents of the beaker were agitated in an electronic stirrer at eight (8) revolutions per minute for ten minutes. The agitation was carried out at 30 C, the temperature commonly employed for hand laundering. After ten minutes the two swatches were separated from the wash water and introduced into 400 ml water for five minutes at four (4) revolutions per minute in a rinse cycle. A temperature of 30C was maintained. The swatches were air-dried and the average reflectance was computed and noted.This procedure was carried out at water hardness levels of Approximately 200, 300 and 400 mg/L respectively. Soiled swatches of clay were also washed and rinsed in distilled water having zero water hardness at the same laundering conditions. Average illuminances of the air-dried swatches were similarly determined. This procedure was repeated for the three detergent types (B, C and D). Soil Anti-Reposition Test [6] Soil redeposition refers to the tendency of soil which is separated from articles being washed by detergents to redeposit on the washed articles, causing them to appear grimy after several washings. A good detergent must function to remove soils from the fabric and suspend them in the wash water. This test provides a method for the determination of laundry detergents ability to performance, more particularly to a method for simultaneously determining both the remove soils from fabrics, as well as suspend these soils in the wash water, thereby preventing their redeposition on the fabrics during the laundry wash cycle. Detergent performance is determined by the quantitative measurement of soil redeposition, and ranking of the effectiveness of different detergent brands in soil removal and soil redeposition with the aid of weight analyses as well as illuminance measurements. Procedure The light incident on sixteen white, unwashed and labeled four-by-three (4”x 3”) terrycloth fabrics were determined by placing them on the white plaque plate of a Light Meter (AVO SM4 model), having one hundred and thirty (130) lux light incident on the plate. The values were noted. The fabrics were weighed individually, and the results were also noted. Twelve of the above-mentioned fabrics were soiled with approximately 3.50 grams of an engine oil and charcoal mixture, known as EMPA 101. These swatches were weighed and allowed to air-dry. 5.83 grams of the first of the four detergent brands to be evaluated, (A) was measured on the electronic weighing balance. 180 mg/L of CaCO3 hard water in a ratio of 3:2 Ca/Mg ions was prepared by the addition of about 140.140 mg/L Calcium Carbonate salt (CaCO3) and 379.450 mg/L of Magnesium Sulphate (Epsom) salt, [MgSO4.7H20] to 50 mg/L tap water. One pre-soiled swatch was introduced into a 2000ml capacity beaker containing the prepared hard water, along with one clean (control) swatch. The measured detergent was added, and the beaker's contents were agitated for five (5) minutes using an electronic stirrer having a constant speed propeller at (8) revolutions per minute. The agitation was carried out at 30C, the temperature commonly employed for hand laundering. The control swatch was separated from this wash cycle and subsequently introduced to a fresh solution consisting of 5.83 grams of the same detergent (A) 180 mg/L CaCO3 equivalent hard water in a ratio of 3:2 Ca/Mg ions. A pre-soiled swatch also having about 3.50 grams of EMPA 101 soil was present. The contents of the beaker were agitated in similar condition as the first. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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After 5 minutes, the control swatch was separated from the second wash cycle, and introduced to the third fresh solution, identical to previous wash cycles. This was laundered for five minutes, after which the control swatch was separated from the wash cycle and hung to dry, along with the pre-soiled swatches. This procedure was repeated for the three detergent brands, earlier represented as B, C and D. The air-dried control as well as pre-soiled swatches were weighed using an electronic weighing balance, to ascertain the weight of soil deposited on, and removed from the control and pre-soiled swatches respectively. The results were noted and tabulated. The control swatches were individually placed on the white plaque of the light meter, to determine the light reflected, and the difference (Delta WIE) between the initial whiteness (initial WIE) of the swatches and the final whiteness (final WIE) were computed. Results and Discussion Soil Removal Test Results Table 1. Soil Removal Test Results at 30ºC Light Intensity (lux) Soil ZeolitePhosphateType Based Based Bentonite 42.5 40.00 34.50 37.00 0 clay 40.0 Bovine 45.00 45.00 40.00 0 blood 22.5 27.50 29.00 25.00 EMPA101 0 Table 2. Soil Removal Test Results at 55ºC Light intensity (lux) Soil Type ZeolitePhosphatebased based Bentonite 44.0 41.2 37.50 35.00 0 5 clay 45.0 37.5 Bovine 35.00 35.50 0 0 blood 25.0 30.0 EMPA 23.75 28.75 0 0 101 Table 3. Percent Cleaning Efficiencies at 30ºC Cleaning Efficiency% Soil ZeolitePhosphateType Based Based Bentonit 74.1 65.5 56.90 48.28 4 2 e clay 66.6 83.3 Bovine 83.33 66.67 7 3 Blood 11.2 27.4 EMPA 32.26 19.35 9 2 101 Table 4. Percent Cleaning Efficiencies at 55ºC Cleaning Efficiency % Soil type ZeolitePhosphatepdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria Bentonite clay Bovine blood EMPA 101

based 79.3 69.8 1 3 88.3 58.3 3 3 19.3 35.4 5 8

based 56.90 48.28 50.00

51.67

15.32

31.45

Complexation of Calcium and Magnesium Ions Table 5. Complexation of Ca2+ and Mg2+ Ions Mg/L Light intensity (lux) CaC PhosphateO3 Zeolite-based based equiv. 38.50 38.75 38.75 39.75 0 37.50 38.00 38.50 39.50 100 36.50 35.25 38.75 37.50 200 37.75 34.75 38.00 33.50 300 32.50 30.50 35.50 30.00 400 Table 6. Percent Cleaning Efficiencies Mg/L % Cleaning efficiency CaC PhosphateO3 Zeolite-based based equiv. 60.34 61.21 61.21 64.66 0 56.90 58.62 60.34 63.79 100 53.45 49.14 61.21 56.90 200 57.76 47.41 58.62 43.10 300 39.66 32.76 50.00 31.03 400 Soil Anti-Redeposition Test Results Table 7. Weights of EMPA 101 swatches DB SNO WBS WAS WAW WD (g) (g) (g) (g) 38 3.63 6.69 5.40 1.29 A 47 3.59 6.61 5.30 1.31 37 3.45 6.69 5.30 1.39 44 3.55 6.82 5.40 1.42 B 22 3.24 6.44 5.00 1.44 39 3.52 7.24 5.80 1.44 52 3.52 6.74 5.20 1.54 C 42 3.25 7.28 5.30 1.98 51 3.42 6.47 4.90 1.54 24 3.23 6.71 4.90 1.81 D 16 3.11 6.61 4.89 1.72 75 3.66 7.06 5.40 1.66 DB SNO WBS WAS

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Detergent Brand Swatch No Weight Befre Soiling Weight After Soiling

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria WAW WD

-

Weight After Wash Weight Defference

Table 8. Whiteness index of control (clean) swatches Detergen Initial Final Difft Brand (WIEi) (WIEf) Erence (∆WIE) 50.00 19.50 30.50 A 50.00 19.75 30.25 B 50.00 30.00 20.00 C 50.00 40.00 10.00 D Table 9: Some Cleaning Efficiency Standards Standard soil/stain removal Type of efficiency (%) detergent Standa (average Particul Protei rd value) ate n greasy phosphate45.5 60 42 based (powder) phosphate31.47 47 28 free (powder) phosphate52 28 based (tablet) phosphate46 22 free (tablet)

Figure 1. Percent Cleaning Efficiency (30 C)

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Figure 2. Percent Cleaning Efficiency (55 C)

Figure 3. Detergent Performance at Varying Degrees of Water Hardness

Figure 4. Percent Soil Anti-Redeposition Discussion of Results Soil Removal The results show that at 30ºC, both zeolite-based detergents had the best efficiency in cleaning particulate soil (clay), brand A performing better than brand B by 8.62 percent. Phosphate-based detergent D performed better than brand C by a similar percentage. This sequence was repeated at 55ºC as well, with the exception that brand C performed better than brand D. This confirms that indeed, zeolite-based detergents can handle particulate soils more effectively than phosphate-based detergents, and generally, both detergent types perform better at this elevated temperature. Table 3 also shows that both phosphate and zeolite-based detergents have very close cleaning pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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efficiencies in terms of blood-stain removal. At 55ºC, however, zeolite-based detergents A has the highest cleaning efficiency of 88.33 percent. It is observed, however, that the cleaning efficiencies are greatly reduced at this temperature, with the exception of brand A. This can be possibly be attributed to the nature of enzymes, which constitute about 0.5 – 2 percent of the detergent formulations B, C and D. At certain enzymes tend to denature at elevated temperatures. Detergent brand A is a non-biological formulation, implying that no enzymes are present. The lowest overall cleaning efficiency for all the detergent types tested occurs when oily/particulate soil is encountered, that is, EMPA 101. Zeolite detergent A has the lowest cleaning efficiency at 30ºC, followed by phosphate brand D, but both detergents perform much better at 55ºC. There is no clear-cut difference between the efficiencies of all four detergent brands tested, however. It is observed that, according to the test results presented in tables 3 and 4. both phosphate and zeolite-based detergents have low cleaning efficiencies generally. It is observed that experimental cleaning efficiency values are comparable with standard values presented in Table 9, with zeolite-based detergents performing even better than the standard in terms of protein as well as particulate stain removal. Complexation of Calcium and Magnesium Ions Detergents perform best in water having negligible water hardness levels, and this is confirmed in table 6. All four detergent brands reach their optimum cleaning efficiency at 0 mg/L CaCO3 equivalent hard water (distilled water), with phosphate-based detergent D having the best value. The cleaning efficiency drops progressively as the water hardness levels increase. At 400 mg/L CaCO3 equivalent hard water, brand D has the lowest efficiency of 30 percent, followed by brand B and subsequently, brand A. Brand C, which has the same efficiency as brand B in distilled water, has the best value at this level of water hardness. These results conform with the theoretical expectation of inverse proportionality, that is, decreasing detergent performance at increasing water hardness levels. The results show that the phosphate-based detergents perform better generally, based on the results presented in table 6. Their efficiencies decrease progressively but are better than the zeolite-based detergents by about 2 percent between 0 and 200 mg/L CaCO3 hard water. Soil Anti-Redeposition Soil redeposition is calculated in terms of the percentage of soil that is redeposited, and it follows that lower soil redeposition values are favoured. Table 7 shows the results of the weights determined. Lower differences in weight between the washed swatches (that have been previously soiled) and unwashed (control) fabrics indicate that more dirt has been removed, implying higher cleaning efficiencies. Phosphate detergents C and D perform better, as shown in the table.According to the American Standards for Testing and Materials (ASTM), higher ∆WIE values (difference in initial fabric whiteness) indicate that there is greater soil redeposition on fabrics, while lower ∆WIEs indicate less soil redeposition and better soil antiredeposition properties. Table 8 shows that both zeolite detergent brands have higher ∆WIE values than brands C and D. Table 9 also shows that both phosphate detergent brands also have better soil antiredeposition properties, with brand D having the highest value of 99.04 percent. Results in tables 8 and 9 tally with findings in table 7, which confirms that phosphate-based detergents have better soil antiredeposition properties than zeolite-based detergents. It is observed that, of all four detergent brands tested, only phosphate brand D lies within the standard ∆WIE range of 5.64 – 10.38, further confirming that it has the best overall soil anti-redeposition properties. However, errors may have led to exceedingly high ∆WIE values for both zeolite-detergent types as well as phosphate brand C, as the swatches employed were left to air-dry for a longer period than swatches employed for testing brand D.

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Conclusions The purpose of this research project has been the evaluation of zeolite-based detergents’ cleaning performance in comparison with the more common but less environmentally friendly phosphate-based detergents. This research work has also considered the possibility of producing zeolite-based detergents in Nigeria. Realistic soil combinations encountered in consumers’ wash load have been carefully selected in order to evaluate the detergents’ performance under varying conditions of water temperature and hardness, and it has been found that zeolite-based detergents are capable of removing proteinaceous and particulate soils more effectively than phosphate-based detergents at an elevated temperature of 55ºC. The lowest overall cleaning efficiency experienced by all the detergent types tested occurs when oily/particulate soil is encountered. Standard cleaning efficiency values concur with this finding. The phosphate and zeolite-based detergents are both capable of complexing calcium and magnesium ions present in hard water, but this research has shown that phosphate-based detergents perform better by a difference of approximately 3 to 7 percent when water hardness levels are between 0 and 200 mg/L calcium carbonate equivalent. Phosphate-based detergents have also been found to have better soil anti-redeposition properties than zeolite-based detergents, but only by a marginal amount of approximately 0.16 percent. It is safe to conclude, therefore, that zeolite-based detergents are efficient, as well as economic alternatives to phosphate-based laundry detergents in Nigeria, as the raw materials required for its production are abundant in the country.

References [1] What a Detergent Is http://www.epa.gov/grtlakes/seahome/housewaste/house/deterg.html; accessed April 19, 2007. [2] Soaps and Detergents http://www.frenchhandlaundry.com/orvus_vs_soap.htm; accessed April 19, 2007. [3] EUROPA Enterprise – Chemicals (June 2006): Non-Surfactant Organic Ingredients and Zeolite-based Detergents. ec.europa.eu/enterprise/chemicals/legislation/detergents/studies/non_surfactant_organic_ingredients_and_ze olite_based_detergents.pdf.; accessed 8 March 2007. [4] Granular Laundry Detergent: US Patent issued on February 21, 1995 http://www.patentstorm.us/patents/5391326·description.html ; accessed April 19, 2007. [5] Liquid laundry detergent composition containing a completely or partially neutralized carboxylic acidcontaining polymer: USPatent issued on March 7, 2000 http://www.patentstorm.us/patents/6034045•description.html accessed April 19, 2007. [6] Army and Air Force Exchange Service (AAFES) Quality Assurance Program http://aafes.com/QA/docs/qa-test_methods_hardlines.htm; accessed August 23, 2007.

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(ICERD08234) Thermochemical conversion of cashew nut shell into fuel and chemical additives 1

Ogunsina, B.O., 2Ojolo, S.J., and 3Falade, M. Imoudu I. 1,3 Agricultural Engineering Department, Obafemi Awolowo University, Ile-Ife. NIGERIA 2 Mechanical Engineering Department, University of Lagos. Corresponding author: S.J. Ojolo; e-mail: [email protected]

1.0

INTRODUCTION

The world demand for fossil fuel has resulted in critical energy situations, thus alternative forms of energy need to be sourced (Fuwape, 1982). Cashew nut shells constitute 70% of the waste from the processing industry which constitutes serious environmental menace and health hazards when incinerated. The global concern to make the world more habitable has resulted in conversion of solid wastes into alternative energy sources thereby abating environmental pollution problems. Cashew nut shells can be one of such viable inputs. The objectives of this work are to determine the heating value of the cashew nut shell, and investigate the pyrolytic conversion of cashew nut shells into fuel as an alternative source of energy. 2.0

MATERIALS AND METHODS

2.1 Equipment and Materials Used In the course of this work, the following equipment and materials were used: Weighing machine, a moisture extracting oven, a ballistic bomb calorimeter, the pyrolytic reactor, a stop watch, polythene bags for packing the sample, and mortar for reducing the particle sizes of the CNS. 2.2 Determination of the Heating Value of the Shell The heating value of the cashew nut shell was determined using the Ballistic bomb calorimeter CB-370. The shell whose heating value was to be determined was grounded to powder form and the bomb calorimeter was used for the determination of the heating value as described by Jekayinfa and Bamgboye (2005). 2.4 Pyrolysis of Cashew Nut Shell 2.4.1 Experimental Procedures The cashew nut shell (CNS) used, were collected form Abod Success Investment Ltd in Ogijo, Lagos State. The CNS was dried in the moisture extracting oven at about 80oC for 24hrs to reduce the moisture content. The reactor was then loaded each time with 800g, 900g and 1060g of CNS respectively and allowed to operate for 8hrs. The tar oil produced was collected in a container embedded in an ice container. The weight and volume of the liquid produced in the container was measured and recorded. The weight and volume of the char left in the retort was measured and recorded. The energy content of the tar oil (Pyrolytic oil) and the char were calculated using Doulong Petti’s formula (Sawayama et al., 1996). The heating value of the tar oil is determined by using the ballistic bomb calorimeter. 3.0

RESULTS AND DISCUSSIONS

3.1 Pyrolysis Tables 2a and 2b show the results of pyrolysis of CNS. There was increase in the volume of the char from the pyrolysis with the increased quality of feed stock. As the quality of feed stock increased, the percentage volume reduction decreased. This can be traced to the possibility of uneven and partial/incomplete combustion of the feedstock for increased quantity of waste. From Table 2a the tar oil yield from 800kg was 0.250l/kg, 0.255l/kg from 900g and 0.265l/kg from 1060g over a residence time of 5.5- 7hrs. Table 2 shows the rate of reduction in the volume of the cashew shells during the experiment. Averagely, the shells were reduced to an average of 320g representing a total reduction of 65% wt/wt. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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This indicates that pyrolysis method could be used to reduce the volume of shell wastes being generated in cashew processing industries. The char produced can be used as “refuse-drived-fuel”(RDF) similar to the use of coal. This showed that the shells can be re-used totally as fuel with nothing left as waste. The product of the pyrolysis showed that instead of the waste constituting a menace to the society, it could serve as an energy source. The char could provide heat for the pyrolysis reactions and it could be used as fuel for domestic purposes such as cooking, heating etc. 68.75% waste reduction was achieved through the pyrolysis process. The char is less bulky through reduction and resource recovery leading to about 85% reduction in waste and production of 0.025dm3 of tar oil from 1kg of waste. The results obtained from the pyrolysis of cashew nut shells are shown in tables below. Table 2a: Tar oil yield from CNS Quantity of waste Residence Time (hr) loaded 800g 5.5 900g 6.5 1060g 7.0

Tar oil yield (l/kg) 0.250 0.255 0.265

Table 2b: CNS weight reduction after pyrolysis Vol. before exp (g) Vol. after exp. (g) 800 250 900 310 1060 400 3.2

Operating Temp. (oC) 700 700 700

% weight Reduction 68.75 65.56 62.26

Ultimate Analysis

Result of ultimate analysis (Table 3) indicates that the chemical elements in CNS are carbon, hydrogen, nitrogen and oxygen, sulphur is absent. The proportion of C, H, O, N determined follows the same trend as those reported by Das and Ganesh (2002). The absence of sulphur in CNS is one of its advantages as a fuel, since sulphur oxidizes to a corrosive gas. Table 3: Ultimate analysis of CNS Element C H N O

Weight (%) 48.7 6.96 0.36 42.96

The calculated HV is 134.92kJ/kg as against 16.69MJ/kg derived from bomb calorimeter results, also the heating value for the tar oil using the bomb calorimeter is 13.17MJ/kg while that obtained from ultimate analysis is 337.86kJ/kg. The variation in heating value between and that obtained from ultimate analysis and that gotten using a bomb calorimeter may be due to little variation in percentage elemental component of CNS and chemical destruction of the bonds between chemical components in CNS, as the process of ultimate analysis creates opportunity for oxidation and this lowers he potential energy of the combustible elements in the shells (Pull, 1964). REFERENCES Fuwape, J. A. 1982. Wood as a source of Energy: A Survey and an Experimental Determination of combustion characteristics of some wood species in Oyo state. An unpublished M.Sc Dissertation, Dept. of Agricultural Engineering. Univ. of Ibadan, Ibadan. Sawayama, S.; Inoke, S.; Tsukahara, K.; and Ogi, T. 1996. Thermochemical Liquidization of anaerobically digested and dewatered sludge and anaerobic treatment. Bioresource Technology. 55:141-144. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Soltes, E. I. 1996. Thermochemical Process for Bio-Energy Production. Biomass Energy Development. Plenum Press, New York. The Seventh Asia-Pacific International Symposium on Combustion and Energy Utilization. 2004. December 15- 17. Hong Kong SAR. UNDP 1999. A Revolutionary Pyrolysis Process for turning Waste-to-Energy, BIOENERGY NEWS, Vol.3, No. 4 September.

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(ICERD 08268) Switching behaviour in Ag/PbSnS3/Al Metal-Semiconductor-Metal (MSM) thin film structures Dr. S. O. Azi and Dr. E. Aghemenloh Department of Physics, University of Benin, Benin-City, Nigeria Abstract Device potential of PbSnS3 for optoelectronic applications was investigated with Ag/PbSnS3/Al Metal – Semiconductor-Metal sandwich structures. Preliminary results indicate current-voltage characteristics that show a switching behaviour. The essential features of the current-voltage characteristics are explained by the theory of a Metal-Insulator-Semiconductor switching diode (MISS). The behaviour is caused by unintentional formation of insulating AgS layer between the Ag/PbSnS3 contact, giving rise to a Ag/AgS/PbSnS3/Al –MISS structure. The switching voltage, Vs and holding voltage, Vh were measured as 80mV and 20mV respectively. The Ag contact later turned out to be unstable. Introduction Many physical phenomena of relevance are due to surface effects on solids, liquids and air. These effects are responsible for the mechanical and electrical properties, as well as the reactivity a surface. Therefore, clean material interface hardly exists, even in ultra high vacuum, because of reaction via its surrounding solid, liquid or gaseous phases. Yet, adequate control these interfaces is the key to many physical, chemical and technological problems. Ironically, optical processes in thin films are wellunderstood while the reaction of substances during the formation of interface layers appears to go through complex transitions. Though often ignored, the stochiometry of these layers largely determine the gross electronic features of thin film devices. Therefore, to a large extent, interface layers influence the technological applications of thin films. Appearance of thin layers in nature has fascinated scientists for a long time. Hence optical phenomena in thin films have been investigated extensively. Technological applications of these films abound ranging from Polaroid films and advanced multi-layer antireflection coating to electronic noses (olfactometry). Thin film semiconductor devices are recently being explored. In particular heat absorbers, reflectors and antireflection coatings have been produced (Green,1982, Elfallal et al, 1992). There are also photonic devices such as solar cells, photodetectors and thin film transistors (Hamakawa,1985). Thin film solar cells of which CuInSe2 cell is the most advanced have remained very expensive (Kim et al, 1993). One of the most challenging research areas of thin films is therefore the development of new and cheap ternary semiconducting compounds (Kazmerski and Emery, 1992). Even at that, stoichiometry which controls the defect electronics of CuInSe2 and other ternary compounds is not well understood,(Kazmerski, 1985). Besides, switching phenomena, discovered by Ovshinsky in 1958, have since been observed in many amorphous semiconductors. For example CdGeAs2 have been studied extensively (Hong and Speyer, 1990). These Ovonic devices or switching diodes are awaiting commercialization. In the present work we present the preliminary result of the device potential of PbSnS3 as a switching diode in the search for new ternary compounds for optoelectronic applications. The switching behaviour was investigated by the use of Metal –Semiconductor-Metal sandwich structure. The structure exhibited similar current-voltage characteristics with a Metal-Insulator-Semiconductor switching diode (MISS). In this paper, we explain the switching characteristics of the four-layer structure Ag/AgS/PbSnS3/Al diode using electronic theory of MISS diode. Theory of the MISS diode A metal-insulator-semiconductor switching diode is a four-layer device. Its physical structure is shown in Figure 1.

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top electrode thin oxide or insulating layer

n+

n epitaxial layer

p+

p+ substrate

wj

Substrate electrode

Figure 1. Four layer structure of the MISS diode The structure comprises of a thin oxide-n-p+ semiconductor sandwiched between two aluminum electrodes. The oxide layer should be thin enough to be permeable to current carriers. The current-voltage characteristic of the above device is shown in Figure 2. I 4- low impedance

3- negative resistance

V

Vs 2- high impedance

1- high impedance

Figure 2. Current-voltage characteristics of the MISS diode

V

The four separate conduction regions are depicted as: reverse bias high impedance region - 1, forward bias high impedance region - 2, negative resistance region - 3, and forward low impedance region 4. The theory underlying various conduction regions may be understood in terms of the idealized energy band diagram of the structure as explained by Simmons and El-Badry, (1977). Figure 3a shows the band diagram of the structure at zero bias. Under reverse bias (see Figure 3b), the applied voltage is dropped mainly across the np+ junction. As such, thermally generated electron-hole pairs in the depletion layer of this junction constitutes the main current across the device which can be expressed as 1/ 2

Ig 

ni g

 e s   2N d

  

Va  Vd 1/ 2

where Va is the bias voltage, Vd the voltage across the device, and other symbols have their usual meanings. This reverse bias current is very small indicating high resistance or a high impedance state in region - 1. Under forward bias, the depletion region develops in the n-oxide interface and grows in the n-region with increase bias, as shown in Figure 3c. The generated electron-hole pairs are swept out of the depletion pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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layer as shown in the figure. If it is further assumed that Va is dropped across the depleted n-layer, the generated current is similarly obtained as in equation (1) and is comparable in magnitude. Again, resulting in the forward high impedance region – 2. As Va is increased further, the depletion layer extends into the np+ junction (see Figure 3d) resulting in punch-through condition. Consequently, the large number of holes injected at the p+ region drifts across the depletion region under the influence of electric field. The field across the oxide layer is insufficient to pass this large influx of holes. This results in a build up of holes at the interface as shown in Figure 3e. This accumulation of holes moves the n-layer from deep depletion towards inversion causing the voltage across the device to drop. Simultaneously, Vox, the voltage across the oxide increases thereby passing larger hole current. The decreasing voltage and increasing current give rise to negative resistance, as shown in region – 3. During switching, region – 4, shown in Figure 3f

Vh  Vox  V j   s

where Vh is the holding voltage, Vj the turn on voltage and s the n-layer surface potential. The above theory was developed for the metal-oxide-np+ semiconductor structure (MISS), but an insulator layer can replace the oxide layer; as long as its thickness lies with 15  and 45  (Habib and Simmons,1979). Also under punch-through conditions, the np+ junction is forward biased and serves as a hole injecting contact, which may be replaced with a suitable metal contact. In principle, a metal-insulatorsemiconductor- metal device. In which the semiconductor-metal contact is an injecting contact, should exhibit switching characteristics. The Ag/PbSnS3/Al switching diode It is well known that metallurgical reactions do occur between contact metals and a component of compound semiconductor films. This process often gives rise to a heterojunction instead of a metalsemiconductor contact. Classical examples are the CdS/CuS junction formed by CdS/Cu contact and CdS/CdTe by CdS/Te (Eisele and Schulz, 1977). During our investigation of various metal contacts on evaporated films, Ag/PbSnS3/Al sandwich structure was prepared. Its current-voltages characteristics is presented in Figure 4. The four conduction regions discussed in the previous section are clearly depicted in the plot. In the forward bias region this device could not be driven above 80mV, which is regarded as the switching voltage Vs, and the holding voltage, Vh, as 20mV. The above characteristics must have resulted from a possible reaction between Ag and S, inadvertently giving Ag/AgS/PbSnS3/Al structure. In a sense, this can be regarded as a metal-insulatorsemiconductor-metal structure.

low impedance region - 4

6.E-07

4.E-07

2.E-07

Vs 0.E+00 -1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

Current (A)

negative resistance region - 3

-2.E-07

high impedance region - 1 -4.E-07

high impedance region - 2 -6.E-07

Voltage (V) Figure 4. Current-voltage characteristics of Ag/PbSnS3/Al MSM structure. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria Semi-insulating layer

xn

p+ substrate

545

wj Ec

Ec s EFm

qVox

EFp Ev

EFp Ev

qVn EFm

(a) Thermal equilibrium (b) Reverse Bias

qVox

qVox

EFm

EFm

Ec

qVn

Ec

qVn EFp Ev

EFp Ev

Depletion

Depletion

(d) At punch-through

(c) Before punch-through

EFm

Ec

qVn

EFm

Ec

qVn EFp Ev + + +

EFp Ev + + +

Depletion (e) Inversion

(f) Low impedance region

Figure 3. Energy band diagram of the MISS diode under various biasing conditions

1

1

Saliu L. B.Sc(Elect), OAU, M.Sc. (Industrial),Ibadan

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Unfortunately, the Ag contact was later found to be unstable, necessitating the search for a more stable contact. The search for a suitable metal-semiconductor contact is a formidable problem (Rhoderick, 1982), further work is being hindered because of the time and resources involved. As aptly put by Eisele and Schulz (1977), there are many variables and uncertainties in the metal-semiconductor system, which depend on the metal, substrates and the thermal history before and after forming the contact. Although it has been proposed that switching diodes should be compatible with standard IC fabrication techniques (Simmons and EI-Badry, 1977) and therefore based on Si or GaAS. These diodes can be made to have switching voltages of 5 V or higher. However application of low voltage switching diodes in the mV and V range exists, such as rectification and detection of microwaves signals (Sze, 1981). The developed structure or any other ovonic switch can be employed for such purposes. Conclusion The device potential of PbSnS3 was investigated with Ag/PbSnS3/Al Metal –Semiconductor-Metal sandwich structures. Preliminary results indicate a switching behaviour and current-voltage characteristics that have the essential features of a Metal-Insulator-Semiconductor switching diode (MISS). The behaviour was probably caused by unintended formation of insulating AgS layer between the Ag/PbSnS3 contact, giving a Ag/AgS/PbSnS3/Al –MISS structure. The switching voltage, Vs and holding voltage, Vh were measured as 80mV and 20mV respectively. The Ag contact was later turned out to be unstable. References Eisele K. and Schulz M. (1977) Metal-Semiconductor junctions – related to deposition of thin films, Vacuum, London, 27,181-188 Elfalllal I, Pilkington R. D., and Hill A. E. (1992) An experimental evaluation of electron beam evaporated Indium Tin Oxide. In: Sayigh A. A. M (ed) Renewable Energy – Technology and the Environment, Oxford, Pergamon Press, Vol 1, 530 –535. Green M. A.. (1982) Solar Cells, New Jersey, Prentice Hall, Ch. 10. Hamakawa Y. (1985) Amorphous silicon solar cells, In: Kazmerski L. L. (ed) Current Topics in Photovoltaics, London, Academic Press, 111-168. Hong K. S. and Speyer R. F. (1990) Switching behaviour in II-IV-V2 amorphous semiconductor systems, Journal of Non-Crystalline solids, Amsterdam, 116, 191-200. Kazmerski L. L. (1985) Cu-ternary Chalcopyrite siolar cells,In: Kazmerski L. L. (ed) Current Topics in Photovoltaics, London, Academic Press, 41-109. Kazmerski L. L. and Emery K. A. (1992) Photovoltaics Technologies: From Atoms to Arrays, In Sayigh A. A. M (ed) Renewable Energy – Technology and the Environment, Oxford, Pergamon Press, Vol 1, 101 –104. Simmons J. G. and El-Badry A.(1977) Theory of switching phenomena in metal/semi-insulator/np+ silicon devices, Solid State Electronics, Oxford, 20, 955-961 Sze S. M. (1981) Physics of Semiconductor Devices, New Delhi, Wiley Eastern, Chapter 2.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

TECHNICAL SESSION 4B: TOOLS, DIES AND MOULDS

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(ICERD08135) RISERING OF A FOUR CAVITY DIE PRODUCTION MOULD BY CONVECTIONAL METHOD L B Zhengwuvi Department of Mechanical Engineering, Federal University of Technology, P.M.B.2076, Yola, Nigeria +2348080392955, [email protected]

This paper demonstrates the possibility of developing skills in sound metal casting of a four cavity die production mould by assessing the riser design criteria and the products/ castings. The assessment takes into account the location of the castings hot pots, casting modulus, liquid metal mass in the risers and the principles of directional solidification. The mould flask is oriented in such a way that a riser is placed directly on top of the castings hot spots for proper feeding during solidification. The assessment result of casting modulus shows that the feeder modulus Mf = 5.85 x 10-3 M and casting hot spot modulus Mh = 1.88 x 10-3 M .The assessment result of castings solidification time shows that the castings solidify within 12 seconds while the feeders solidify within 30 seconds. From the assessment results it is observed that the risers hold liquid metal, feed the castings to full solidification and solidify later than the castings which they feed up. Examinations at the cross sections of the single- cylinder engine pistons (castings after finishing) manufactured by the die production mould reveal the absence of void formation which is a clear indication of effective and functional risers. Thus the risers have achieved the desired requirement.

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(ICERD 08139) Computer Aided Design and Drafting (CADD) Modeling for Gas Welding Process

S. B. Adejuyigbe and A.A. Adekunle Mechanical Engineering Department, Federal university of Technology, Akure, Ondo State of Nigeria. E-Mail: [email protected] Keywords: Computer Aided design, Drafting, Modelling, Gas Welding. Abstract: The application of computer technology offers the potential to reduce a product cycle time through Computer –Aided Design and Drafting (CADD) applications. CADD is the use of computer systems to assist in creation, modification, analysis, drawing or optimization of design. Welding operation is joining two metals together. The need arise for how to minimize or eliminate the error encountered when fatigue sets in, due to low efficiency of the local welder. CADD software for welding was developed using Microsoft Visual Basic 6.0 which was used to weld two mild steel plates together automatically. The result of the research clearly shows that robotic welding is faster, error free and uniformly welded all through like that of the CADD welding model developed. It is highly suggested and recommended that further work on robotics can be embark upon to bring Nigeria to the level of Industrialized Nation. Introduction As computers became more affordable, the application areas have gradually expanded. The development of CADD software for personal desk-top computers was the impetus for almost universal application in all areas of construction. As a general rule, one CADD operator could readily replace at least four or five drafters using traditional methods. Additionally, many engineers began to do their own drafting work, further eliminating the need for traditional drafting departments. This trend mirrored that of the elimination of many office jobs traditionally performed by a secretary as word processors, spreadsheets, databases, etc became standard software packages that "everyone" was expected to learn. Today CADD is not limited to drafting and rendering, and it ventures into many more "intellectual" areas of a designer's expertise. Computer aided design is used in many businesses and organizations around the world. Consequently, a need arises for development of software to aid in model development and at the same time draw the welding operation to ease fabrication.[1,2] CAD/CAM Database The important reason for the development and the use of Computer Aided Design (CAD) system is that it offers the opportunity to develop the database needed to manufacture the product. In the past, engineering drawings were prepared by design craft men and then used by manufacturing engineering to develop the process plan. This is a separate function, which involve a two-step procedure, that is, design and manufacturing. But in an integrated CAD/CAM system, a direct link is established between product design, drafting and manufacturing. The CAD/CAM had the goal of automating certain phases of design and certain phases of manufacturing, and also to automate the transition form design to manufacturing. The role of computer-based systems is to create much of the data and documentation required to plan and manages the manufacturing operations for the product. The manufacturing database is also an integrated CAD/CAM database. [3, 4] Welding Welding, in engineering, is any process in which two or more pieces of metals are joined together by the application of heat, pressure, or a combination of both. Most of the processes may be grouped into two main categories namely pressure welding, in which the weld is achieved by pressure; and heat welding, in which the weld is achieved by heat. Heat welding is the most common welding process used today. Brazing and soldering are other means of joining metals [5, 6]. Gas Welding Process pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Gas welding is a non-pressure process using heat from a gas flame directly to the metal edges to be joined and simultaneously to a filter metal in wire or rod form, called the welding rod, which is melted to the joint. Gas welding has the advantage of involving equipment that is portable and does not require an electric power source. The surface to be welded and the welding rod are coated with flux, a fusible material that shields the material from air, which would result in a defective weld [7, 8, 9] The objectives of the research therefore are to:  develop a Computer .Aided Design and Drafting software for welding;  use the developed software to weld a plate of mild steel automatically; and  compare the CAD gas welding developed with robotic welding in the case study industry. Research Methodology In carrying out this research, Renoyld Construction Company, Ogbomoso site office, was visited where robotic welding operation was observed, and Mechanical Engineering Department of Ladoke Akintola University, Ogbomoso, where manual welding was performed, both in Oyo State. The artisan welders at Ogbomosho were also visited to learn some of their primitive ways of welding. CADD Software was developed using Microsoft visual basic 6.0 which was used to automatic weld two mild steel plates together. Usage of CADD Files to Generate Welding Program Currently, since the vast majority of companies used CAD programs to design their products, information from CAD files could used to generate robotic welding program. [10, 3]. . The generated data file is used as input for the application used in this research. Application shows the available definition with the help of several push-down buttons, and enables the user to change the welding parameters, correct point and orientations, simulate the whole process using the real robot and the real piece to weld. The simulation is very realistic, making the final program ready for production. Results and Discussion Results of the CADD Software for Gas Welding Developed The following shows the sequence of welding operation obtained in this research.( Plates 1-12)

PLATE 1 Plate 1 has the Process at the left corner at the top which has the menu table that contains the process to be followed stepwise in order to achieve the expected result.

PLATE 2 Clicking the process at the top left corner in the plate 1, the table in the plate 2 above would be displayed as shown in the plate 2 above. What we have there in the table is as shown above, i.e. Settings, Reset, Clear, Weld, and Exit, in descending order. Clicking Settings brought about what we have in plate 2, that is, the XpdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Y position of the plates would be displayed and changed if need be, and if Clear is clicked, the plates will disappear automatically. Also if Weld is clicked, welding parameters would be displayed, and whatever we input as Start and Stop positions would be displayed and effected.

PLATE 3 Clicking the process, displayed the settings table. This settings table contained the X position and Y position of plate A and Plate B, at the same time the height and width of plate B, all in millimeters. This is being displayed automatically on plate 3. Draw and Close is situated at the base of the table to effect the input figure.

PLATE 4 The plate 4 shows the plates to be welded. Inputting 800mm and 6000mm d for X and Y co-ordinate of plate A, while the size of the plate B is 3000mm in height and 3000mm in width, then, clicking Draw will automatically display the figure shown above.

PLATE 5 Clicking close button automatically made the table to disappear. The initial table that we had in plate 4 would be left on the screen. After that, clicking process, and then weld on the menu table where we have process. What we are going to have is the next plate 5 shown above.

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PLATE 6 In plate 6 a table with welding torch at the top will be shown. The starting position on plate B and Stop position on plate B will be shown, then Weld and Close box to execute any computed figure will also be shpown.

PLATE 7 The plate 7 shows the start position which was inputted as zero, and stop position input was 2500mm, then weld button was clicked. What we are going to have is the next plate.

PLATE In plate 8, the welding operation commenced automatically starting from zero position as shown.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

PLATE 9 Plate 9 shows the automatic welding operations continuation.

PLATE 10 Plate 10 shows the welding operation still in progress.

PLATE 11 Plate 11 shows the automatic gas welding operation at an advanced stage.

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Plate 12 Plate 12 shows the automatic gas welding operation completed. It stopped at the input figure which was 2500mm. The materials’ positions can be varied and at the same time, weld’s stop position can be altered. Consequently, various welding position was captured. Comparing Robotic Welding, CADD Developed Welding and Manual Welding The error always encountered in robotic welding is always minimal compared to that of the manual welding. A robotic welding system may perform more operation repeatedly than a manual welder because of the monotony of the task . Another consideration with manual welding of large components is the arduous nature of the work. There is a risk of neck injury if the head is held for too long in one position and additionally, continuous feeding of wire into a joint can cause repetition strain injury. Such health and safety issues are eliminated if a robot is used. On the other hand, manual welding is cost effective compare to the robotic welding. Cost of maintenance of robots is so exorbitant to the extent that ordinary person cannot afford it. Conclusion and Recommendation CADD software for welding was developed using Microsoft visual basic 6.0 which was used to weld two mild steel plates together automatically. Robotic welding operation performed at Renoyld Construction Company (RCC) was critically examined, and this is compared with the CADD welding process developed. The result clearly shows that Computer Aided Welding developed and the Robotic welding carried out are faster, error free and uniformly welded all through when compared with manual welding. It is highly suggested and recommended that further research work on robotics and automatic welding should be embark upon to bring Nigeria to the level of Industrialized Nation. References [1] S.B. Adejuyigbe - CAD/CAM for Manufacturing. TOPFUN Publications, Akure, Nigeria (2002) [2] P.C.J Andersen - A Review of Sensor Systems for the Top Face Control of Weld Penetration. The TWI Journal, (1997) Vol. 6, No. 4 pp. 654-697 [3] E. Freund and J. Rossmann - Projective Virtual Reality: Bridging the Gap between Virtual Reality and Robotics. IEEE Trans. on Robotics and Automation. (2000) Vol. 16 No. 6 pp [4] J. Angeles, G. Soucy, and, F.P. Ferrie - The Online Solution of the Hand-Eye Problem. IEEE Trans. on Robotics and Automation. (2000) Vol. 16 No. 6 pp [5] D. Brzakovic, and D.T Khani - Weld Pool Edge Detection for Automated Control of Welding, IEEE Trans. Robotics and Automation, (1991) Vol. 7(3), pp 397-403 [6] J.J. Craig. - Introduction to Robotics: Mechanics and Control. Addison-Wesley (1989) [7] D. Dye, O. Hunziker, S.M. Roberts and R.C. Reed, - “Modeling of the Mechanical Effects Induced by the Tungsten Inert Gas Welding of IN718 Super alloy.” Met. Trans., (2001) 32A, pp. 1713-1725. [8] Durrant-Whyte, H.F. (1988) Integration, Coordination and Control of Multi-Sensor. Robot Systems. Kluwer, [9] G. Cam and M. Kocak, (1998) “Progress in Joining of Advanced Materials.” International Materials Reviews, 43, No. 1, pp. 1-44. [10] Gonzalez, R.C. and Woods, R.E.(1993) Digital Image Processing, Addison-Wesley,

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(ICERD08140) COMPUTER AIDED MODEL FOR CASTING ALUMINUM USING DIE – CASTING

Adejuyigbe, S.B. , Mogaji, P.B. and Bada, O.M.T. Mechanical Engineering Department, Federal Univerfsity of Technology, Akure, Ondo State, Nigeria.

This research is on computer aided casting of aluminum using die-casting. A piston, which is an automobile part and very important in internal combination engine, was chosen for the research. Pistons are made of aluminium alloy. Models of the products were developed to aid the casting process. Mathematical models that show the dimensions of the casting were also developed.Since the project is about using computer to aid casting process, a programme using Visual Basic Language was developed. The programme was used to incorporate die-casting process into computer system. The process flowchart was developed from the developed programme. The written programme was tested and the model of the casting product (piston) was displayed. The result shows that computer which is faster with accurate result can be used as an aid in the production of aluminum using die-casting process, for accurate planning in the manufacture of the product.

Keywords: Computer Aided, Model, Casting, Aluminium, Die Casting

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(ICERD 08236) Computerised design approach to a sub-press mould for composite materials manufacture I. M. Dagwa(1) and A.O.A. Ibhadode(2) (1)

Department of Mechanical Engineering, University of Abuja, Abuja Email:[email protected] (2) Department of Production Engineering, University of Benin, Benin-City Email:[email protected] ABSTRACT This paper focuses on the design of a Sub-press mould mounted on a 100-Tonne hydraulic press during compression moulding of composite materials manufacturing process. The Sub-press consisting of platens, punch and mould, and guide columns were designed using a Microsoft Visual Basic software to minimize time wastages in trail-and-error procedures and mould modifications resulting after the mould is manufactured. Graphical representations of variables which were used in the design such as: platen thickness, guide pin dimensions, clamping force, heat supply, heat losses, and heating element were presented. The program developed was tested on a solved example in a standard textbook and the result obtained compared favourably well with the result in the book. 1.0 INTRODUCTION Compression moulding is one of the widely used methods in the manufacture of composite materials, which involves introducing of a specific charge quantity of thermosetting plastic raw material, into the cavity of a pre-heated die. The charge could either be in granular or palletized pre-form condition. A die plunger (punch) is pressed from above into die cavity to mould the charge into shape under pressure and heat until full thermo-chemical cure is accomplished. Thereafter, the product is removed from the mould and a new cycle can be commenced immediately [1]. The compression moulding process is widely used in automotive, aerospace, sporting goods, and electronics industries to produce parts that are large, thin, lightweight, strong and stiff [2]. Compression molding parts are shown in Fig. 1. Composite materials are formed as a combination of two or more different material components usually consisting of a reinforcing agent and a resin (binder). As reported [3] the use of composite has grown in importance over the last two decades. This is consequent to the demand for materials with high strength-to-weight ratio especially in automobile towards fuel economy as the fuel price has been on the increase for sometimes now. There is also the growing interest in the use of renewable, recyclable and reusable materials in the 21st century. Especially biomass based resources (which are a good source of biofibres) because of environmental and economic considerations towards sustainable global economy. According to Masayuki and Dauda [4] an estimate of more than 2 billion metric tons of agro-based raw materials from crop residues are potentially available. This therefore suggests that as some of the reinforcing fibres used in composite materials are of plant origin, there is a tremendous source of raw materials available for developing new value-added materials. There are different methods that are used for the fabrication of composite materials. However, the compression moulding technique is being considered in this paper because of its simplicity. Nevertheless most of the compression moulding equipment are imported and expensive. As reported [2], there is increasing requirements to decrease costs, improve quality, and reduce cycle time hence; the use of computer aided engineering is paramount for profitability. Furthermore, with the use of computer aided design tedious calculations encountered in designs are simplified [5]. In particular, by reducing the machine size and weight through a good

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Die Plunger Compressive Load

Composite Material

Hot Mould

Ejector Pins Fig. 1 Compression Moulding

design work, the cost of the machine is substantially reduced due to lower material utilization and reduced actuator requirement [6 ]. In the view of the above, a comprehensive understanding of both the materials and the manufacturing processes involved are critical. This paper is therefore aimed at a computerized design of a sub-press, which is used in compression moulding of composite materials such as brake pad. Hence minimizing energy, time and, wastages encountered in manufacturing process towards a better profit making. The compression moulding device could be used for composite materials research and development. 2.0 METHODOLGY In the development of the software, an algorithm was first developed. Subsequently, formulas were used in determining the design parameters, which were programmed using a user friendly Microsoft Visual Basic programming Language [7,8] that offered an object oriented programming language in order to build an appropriate graphics interface. 2.1 Algorithm of Software: The algorithm considered for the mold design was as follows: (i) (ii) (iii) (iv) (v) (vi) (vii) (viii)

Thickness of platen Guide pin diameter Spring design Mould Heat requirement Heat losses Useful heat Heating element length and diameter

2.2. Sub-Press Structure 2.2.1. Platen Design The sub-press as shown in Fig 3.2 is principally made up of the top and bottom platens, punch and mould, and the frame supports. It is separated by poor conducting material, that is, high-density plywood from getting direct contact with the hydraulic press table and piston. The thickness of the platen is designed to withstand the clamping force from the hydraulic press that is experienced during compression moulding of composite materials. During the moulding operation the platens and punch are subjected to compressive stress. Based on the work of Grashof and Bach as reported [9], the thickness (t) of a rectangular plate subjected to a compressive force (Fa) uniformly distributed over the total area is given by the following formula:

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria t  abk1 where a b K1 Fa ót

= = = = =

558

Fa --------------------(1)  t a 2  b 2  Length of the plate (m) Width of the plate (m) Coefficient of mild steel rectangular plate Compressive force N/m2 Allowable design stress on mild steel (N/ m2)

Considering the safety factor (Fs1), the actual thickness is given thus: t a  t  Fs1 ---------------------------------(2) Hence, the mass (M) is given ass; M  1  a  b  t a -------------------------(3) ñ1 = density kg/ m2 Therefore, the weight of platen is: Wt  M  9.81 ------------------------------(4) Similarly the bottom platen has the same size and weight. The thickness of the mould was chosen as 35mm so that the cavity could accommodate the charge enough to produce a component. 375 mm

125 mm

11 9 13 4 14 5 6 257 mm 10 7 8

3 2 12 1 Key 1. 2. 3. 4. 5. 6. 7.

M10 Bolt Wood Insulator Guide Pillar Compression Spring Washer Mould arm Bushing

Fig. 2 Sup-press

8. Arm Rest 9. Top Platen arm 10. Bottom Platen arm 11. Top Platen 12. Bottom Platen 13. Punch 14. Mould Cavity

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2.2.2. Guide Pin Design Although the top and bottom platens and the mould are aligned using a guide pillar passing through the armrest (bracket), a guide pin is also provided to ensure that the punch goes into the mould cavity during its operation. Hence, it is important to design for the guide pin so that it does not fail under compressive load. Given that a working load (WL) of 98100N and press piston of 67mm diameter the critical load (Wcr) to avoid buckling is given by the formula [9]:

Wcr  W p  Fs 2 ------------------------------(5) Where: Fs2 = factor safety But the load acting on the platen Wp is:

Wp 

a  b  Wl  4 2 d pp

---------------------(6)

Where dpp = the diameter of press piston Since the guide pin is similar to a push rod; therefore the equivalent length of the guide pin is equal to the actual length of the guide pin. Using Euler’s equation[9]:

Wcr 

 3 Ed p4 64L2

where L = dp = E =

-------------------------(7) Length of guide pin diameter of guide pin Modulus of elasticity N/mm2

From equation (7), the guide pin diameter for the sub-press was obtained as:

dp  4

64Wcr L2 -------------------------(8)  3E

2.2.3. Spring design The choice of two compression springs in order to support the top platen when the sub-press is not engaged was based on their deflection (ä) thus [8]:

8Wt D 3 n   Ps ------------------(9) 4 Gd sw where P n dsw D Wt G

= = = = = =

Pitch of spring mm Number of turns Diameter of wire mm Outside diameter of spring mm Weight of top platen N Modulus of rigidity N/m m2

2.2.4. Heat Analysis for Mould After the components design of the sub-press, it is important to determine the power input required to maintain the operating temperature of the mould to aid the curing of the charge in the mould. The amount of heat (Q1) that is needed to heat the platens and mould is as follows [10]: Q1  M 1  c  (Tw  T ) ----------------(10) where c = Specific heat capacity J /kg K pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Tw = Temperature of the plate or mould oC T∞ = Temperature of the surrounding. M1 = Total mass of platens and mould Generally, there are three modes by which heat can be transferred. And it is important to consider these heat losses from the energy generated (Q1). They are: Heat loss by convection Qconv due to the movement of the fluid on the surface of the hot mould as a result of differences in densities because of the temperature differences as in natural or free convention. Qconv is given as follows [9]:

Qcov  hc  AT (Tw  T ) ---------(11) where hc = AT =

Convective heat transfer coefficient W/ m2 C Surface area m2

Heat loss by conduction Qcond, which occurs through the top and bottom platens. The platens are separated from the hydraulic press through a high-density wood, which serves as an insulator. Qcond is given by

Qcond 

kAT Tw  273  T  273 -(12) ti

where k = Thermal conductivity W/mK ti = Thickness of insulator Heat loss through radiation Qrad since higher temperature bodies emit more electromagnetic wave compared to cold bodies. This is as follows [10]:



4

4



Qrad  FeFg AT Tw  273  T  273 -------(13) Where Fe =Surface emissivity of steel = 0.8 Fg =View factor (negligible) ó

=

Stefan – Boltzmann constant W/ m2 K 4

Hence the total heat losses Qt is: Qt  Qrad  Qcond  Qconv ----------------(14) Therefore the total heat requirement = useful energy for heating the mould + heat losses (Qt). Assuming the holding time (Th) per operation is 8 minutes. Then the power required P (Watts) is given thus:

P

Q1  Qt -----------------------(15) Th  60

2.2.5. Design of Heating Element Usually heating elements are made from circular cross-section or rectangular conducting ribbons. For a steady-state condition, a heating element dissipates as much heat from its surface as it receives the power from electric supply. Hence, if P is the power input and H is the heat dissipated by radiation, then P = H under steady-state conditions. According to Stefan’s Law of radiation, heat radiates by a hot body is given as follows [11]:

 T1  4  Tw  273  4  H  5.72e m k r    --------(16)    100   100   pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria Kr em

= =

561

Radiating efficiency Emmisivity of heating element

Diameter of heating (dh) wire is given by:

dw  3

P 2 ----------------------(17) 2.4649 Hv 2

where ñ = Resistivity of material Ωm V = Voltage And the length of heating wire is obtained by using the formula:

l

d wv 2 -------------------------------(18) 4 H

3.0 RESULTS AND DISCUSSION The following example was used in test running the software. Example [11] A resistance oven employing nichrome wire is to be operated from 220V single-phase supply and is to be rated at 16kW. If the temperature of the element is to be limited to 1170oC and average temperature of the charge is 500oC, find the diameter and length of the element wire. Radiating efficiency = 0.57, Emmissivity = 0.9, specific resistance of nichrome = 109 x 10-8 ohm-m. Solution: By using equations 17 and 18 the length (l) and the diameter of the element wire were obtained as 16.05m and 2.716mm respectively by using the software. Further Test Run By varying the clamping load as follows; 2, 4, 6, 8 and 10 tons and maintaining the theoretical mould temperature at 160oC the following results were obtained: Figure 3 shows the effect of varying the clamping pressure on the size of guide pin diameter for the mould set. From the figure it is observed that as the clamping pressure required to compress a charge increases there is a corresponding need to increase the guide pin diameter that can withstand possible compressive load during the initial alignment of the mould set. Similarly, there is also a corresponding increase in platen thickness when the clamping force is increased; this is presented in Figure 4. It is known that in compression moulding exercise, there is simultaneous application of pressure and heat on the charge in the mould. Owing to heat losses which are mainly through conduction, convection and radiation, not all the heat used in heating the platens and mould are utilized. As the heat generated increased the amount of heat losses also increased correspondingly but not sharply as shown in figure 5. The quantity of heat losses were as follows in the descending order: conduction, radiation, and convection. As the dimensions of the platen and mould were increased it was observed that the quantity of heat required for the charge to attain its curing temperature also increased. The heat energy was provided through the heating element. It was observed that as the power requirement increased there was a corresponding increase in the length of the heating element as illustrated in figure 6.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

Fig. 3: Clamping pressure and guide pin diameter

Fig. 4: Clamping force and platen thickness

Fig. 5:

Heat generated and useful heat

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Fig. 6: Power required and length of heating wire

Fig. 7: Heat losses and heat generated

4.0. Conclusion and Recommendation The software developed has demonstrated that tedious design calculations encountered in mould design could be made much easier and more efficient. It has also shown graphically the effect of varying the design parameters. It is recommended that instrumentation and the use of programmable logic controller will be incorporated in future work. 5.0. References [1] A.O.A Ibhadode, Introduction to manufacturing Technology Ambick press Benin City 2001. [2] A. Rios, B. Davis and P. Gramann, Computer Aided Engineering in Compression Moulding. The Madison Group: Polymer Processing Research Corporation //www.madisongroup.com/publications/cae.pdf (accessed march,2008)

http:

[3] A.S. Ahmed, Materials Selection for Process Equipment in Basic Concepts in Process Equipment and Plant design, A. Kuye and D.B. Ayo (Eds) A Publication of: Raw Materials Research & Development Council, Abuja, Nigeria (2007) 107 – 132. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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[4] M. Yoshiba and M. Dauda, Rationalization of Materials and Thermal Recovery System for NonWoody Agricultural Wastes, Transactions of the Materials Research Society of Japan 25 (3) (2000)685688. [5] J.A.Akpobi and P. Oboh, Internal Combustion Engines; A Computerized Design Approach, Advance Material Research, Trans Tech Publications, Switzerland, Vols. 18-19 (2007)423-433. [6] N.Doshi and D. Kazmer, Layout Design of a Platen less Molding Machine, ANTEC, PP 3539 – 3543 http://kazmer.uml.edu/staff/archieve/2003ANTEC_platenless(accessed march 2008) [7] S.J. Podlin and P. Palmer, Hands on Visual Basic 6,Tech Publications Pte Ltd., Singapore. [8] B. Siler and J.Spotts, Using Visual Basic 6(special edition),Macmillan Computer Publishing, Indianapolis,USA. [9] R.S. Khurmi and J.K. Gupta, Machine Design, Prentice- Hall, India, 2003. [10] J.P. Holman, Heat Transfer, 8th Edition, McGraw-Hill Co., New York, 1997. [11] B.L. Theraja and A.K.Theraja, A textbook of Electrical Technology, S.Chand & Company Ltd. New Delhi, 2008.

NOMENCLATURE A =Surface area (m2) a =Length of the plate (m) b. =Width of the plate (m) C =Specific heat capacity (J /kg K) D =Outside diameter of spring (mm) dh =Diameter of heating wire(m) dp =diameter of guide pin(m) dpp = diameter of press piston(m) dsw = Diameter of wire mm(m) E =Modulus of elasticity (N/m2) em =Emmisivity of heating element Fe =Surface emissivity of steel = 0.8 Fg =View factor (negligible) Fa =Compressive force (N/m2) G =Modulus of rigidity N/m2) H =Heat radiation or dissipated (J) hc =Convective heat transfer coeff (W/m2 C) I =Moment of intertia (m4) k =Thermal conductivity (W/mK) K1 =Coefficient of mild steel rectangular plate Kr =Radiating efficiency L =Length of guide pin(m) l =Length of heating wire(m) M =Mass of platen (kg) M1 =Total mass of platens and mould (kg) n =Number of turns P =Power input (W) Ps =Pitch of spring (m) =Energy needed to heat the platens and mould(J) Q1 Qcond =Heat loss by conduction pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria Qconv Qrad t. ta Th Tù T∞ V Wl Wt Wcr Wp ót ñ ñ1 ä ó

=Heat loss by convection (W) =Heat loss by radiation (W) =Platen thickness (m) =actual thickness of Platen (m) =Holding time (minutes) =Temperature of the plate or mould ( oC) =Temperature of the fluid or air( oC) =Voltage (V) =Working load (N) =Weight of top platen (N) =Buckling load (N) =Load acting on platen (N) =Allowable design stress on mild steel (N/ m2) =Resistivity of material (Ωm) =density (kg/ m2) =Deflection of the spring (m) =Stefan – Boltzmann constant (W/ m2 K 4)

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(ICERD08254) Computer-Aided Design (CAD) of a completely closed-cavity die forging die by the Die Expansion Method P.E.Amiolemhen1,a , A.O.A. Ibhadode2,b 1

Department of Technology, Nigerian Institute For Oil Palm Research (NIFOR), P.M.B. 1030, Benin City, Nigeria. 2 Department of Production Engineering, University of Benin, P.M.B. 1154, Benin City, Nigeria. a [email protected], b [email protected]

Abstract A computer-Aided Design (CAD) package has been developed with MS Visual Basic 6.0 and the package applied to the design of a completely closed-cavity die forging die by the Die Expansion Method. This involves the design of the Monoplex die parameters; selection of the multiplex die parameters as well as the selection of the punch/counterpunch dimensions. The CAD package developed is user-friendly and interactive. The results obtained compare favourably well with the experimental work done in this area. Keywords: Die expansion, Monoplex die, multiplex die, punch/counterpunch, CAD Introduction In completely closed-cavity die forging, as in other applications where the cylindrical die is subjected to very high pressures, the dies are usually compounded by shrinking one cylinder into another to increase the strength [1]. In addition to increasing die strength, die compounding also increases the die stiffness, which reduces die expansion. Ibhadode [2] has shown that a method based on die expansion may be used to select the external diameter of a die with respect to the specified forging tolerance. Amiolemhen et al [3] showed that optimum machining parameters are required to determine minimum production cost of dies. In this paper, an interactive Computer-Aided Design (CAD) package of a completely closed-cavity die forging die by the Die Expansion Method is used to select the optimum parameters of a multiplex die; determine optimum machining cost of the die as well as to select punch/counterpunch dimensions; in order to have minimum die expansion. Methodology This involves the development of a computer program structure in MS Visual Basic 6.0 in order to have an interactive and user-friendly CAD package and the implementation of this package to: (a.) Design the Monoplex die; - Specify the workpiece and the die container material properties. - Calculate the effective workpiece volume, Vo. - Determine the minimum allowable tolerance on forging diameter, ∆Dmin. - Select a tolerance on forging workpiece diameter, ∆D>∆Dmin. - Determine the die elastic constant, â1 for the Monoplex Die. - Determine the minimum external die radius, bmin. - Select an external die radius for the Monoplex Die, b1> bmin. (b.) Design the Multiplex dies; pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria -

567

Determine the die expansion, ∆a1 and the maximum die stress, óèm1 for the Monoplex Die. Using b1 above, determine the die expansion, ∆anb1 and the maximum die stress, óèmnb1 for the multiplex dies. Where n=2,3,4, etc and ∆anb1 and óèmnb1 are the die expansion and the maximum die stress respectively for the multiplex die at the external die radius, b1.

(c.) Select the multiplex dies, based on a reduced external die radius; By trial-and-error method determine an appropriate external die radius bn, such that: bn> b1. Using bn above, determine the die expansion, ∆anbn and the minimum resultant maximum circumferential die stress, óèmnbn for the multiplex dies; such that: ∆anb1 ∆Hmin; or percentage volume variation of workpiece, V > Vmin. - Determine the maximum die elastic column, lecm. - Select length of die elastic column, lec 0 K = 2/3 K 10-3, the link is said to be unavailable. If the BER is >10-6, then the link is available.[6] -9

6

x 10

4

y = - 3.3e-014*x 7 - 9.9e-012*x 6 - 1.3e-009*x 5 - 9.1e-008*x 4 - 3.9e-006*x 3 - 0.0001*x 2 0.0014*x - 0.0087

BER

2

0

-2

Data point Model curve

-4

-6 -50

-48

-46

-44

-42

-40

-38

-36

RSL(dBM)

Fig. 3.2: A Graph showing Received BER against Received Signal Level for the Year 2005 The significance of BER versus RSL graph is that it shows the bit error rate in the Akure –Owo digital transmitted link. From Fig.3.2, we can deduce that: (i) The BER is good and available since BER > 10-6 (ii) For small variations around the nominal receive level,the BER is unaffected.It is only when one approaches the knee of the threshold area that the receive level variations will have a dramatic effect on BER. (vi) Development of an appropriate Atmospheric Propagation model for the link investigated. The key issue in microwave radio propagation planning is the prediction of received signal strength in the investigated link. It is therefore pertinent to develop a model to predict signal strength and bit error rate in the link investigated. Propagation model is a set of mathematical expression diagram and algorithms used to represent the radio characteristics of a typical link. [7,8]. The propagation model used to predict the received signal level and bit error rate was developed with the help of Matlab 7.0 software program. The data obtained were tested with linear, quadratic and cubic pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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model and the best fit was found to be polynomial of the 7th order degree represented by equations 16 and 17, 1. y  0.004x 7  0.019x 6  0.36x 5  3.5 x 4  19.x 3  60x 2  96x  98 …………. (16) y   3 . 3  10  14 x 7  9 . 9  10  12 x 6  1 . 3  10  8 x 4 ………….. (17) 2.  3 . 9  10

 6

x

3

 0 . 0001

x

2

 0 . 0014

x  0 . 0087

(vii) Comparison of Prediction with measurement The results of the predicted propagation model were compared with the measured data for both the received signal level and bit error rates as shown in Table 3.3 and 3.4 and Fig 3.3 and 3.4. Table 3.3: Received Signal Level and Predicted value with Months for Year 2005 Months RSL RSL Error (dbm) (dbm)

(dbm)

measured

predicted

1.

– 46.0

–45.9

0.002

2.

– 37.0

–37.6

–0.016

3.

–40.0

–38.9

0.028

4.

–40.0

–42.7

–0.018

5.

–42.0

–42.8

–0.019

6.

–47.0

–45.9

0.023

7.

–49.0

–48.9

–0.012

8.

–49.0

–49.6

–0.002

9.

–47.0

–47.1

0.014

10.

–44.0

–43.4

–0.003

11.

–41.0

–42.4

0.002

12.

–45.0

–44.9

–0.100

-35 data linear

y = 1*x + 1.6

-40

-45

-50 -50

-48

-46

-44

-42

-40

-38

-36

Fig 3.3 A Graph of Measured received signal level against predicted received signal level for Year 2005 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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Table 3.4: Received signal level, Bit Error rate measured and predicted for year 2005 Months

RSL

Bit Error

Bit Error

(dBm)

Rate

Rate

Measured

Measured

Predicted x

x 10-10

10-10

10 data 1 linear

9

1

– 46.0

8.2

2

– 37.0

3.9

3.9

3

–40.0

4.0

4.0

7

4

–40.0

4.0

4.0

6

5

–42.0

5.0

5.0

6

–47.0

8.0

8.0

7

–49.0

9.3

9.3

8

–49.0

9.3

9.3

9

–47.0

8.0

8.0

10

–44.0

5.0

5.0

Fig 3.4 A graph of Bit error rate measured,

11

–41.0

4.0

4.0

versus Bit error rate predicted for year 2005

12

–45.0

7.5

7.5

8

5

4

3

3

4

5

6

7

8

9

The models were validated by testing with the measured values and the results obtained showed an error of -0.2% in the year 2005 for the received signal level. Therefore it can be deduced that the model developed to predict the received signal level is good. Also the model for the bit error rate was validated by testing with the measured values and the results obtained showed that there was no error between the predicted and measured values in the year 2005 hence the model is very accurate. 4.0 Conclusion In this study an analysis of microwave link degradation due to atmospheric conditions was carried out. The result of the study allow us to conclude as follows: i. There is no multipath fading in Akure – Owo microwave link but there are signal degradation of between – 0.97dBm to -4.97dB during the months of June, July, August, September, and January. This is because the weather is cold and damp in June, July, August, and September and hazy with low relative humidity in January. ii. The bit error rate in the link investigated is greater than 10-6 therefore, the link is available, that is good and acceptable throughout the months of the year. iii. The model equations that have been developed to predict the link investigated degradation parameters are reasonably accurate. 6.0 1. 2. 3. 4.

REFERENCES www.answers.com – Microwave radio relay Manning T. (1999) “Microwave Radio Transmission Guide” British Library Cataloguing in the Publications data, pp 89-115, 177-201. Ofulue J.O. (1990); “Causes of High Failure Rate in Nigeria Telephone System.” P.hD Thesis. University of Benin, Benin City. Owolabi I. E. (1987); “Tropospheric Radio Propagation Studies in African Workshop and Application Buerios Aires, Argentina”.

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10

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria 5. 6. 7.

8.

965

Eyo O. E., Menkiti S. O., and Udo O. (2003); “Microwave Signal Attenuation in Harmattan Weather Along Calabar-Akampkpa Line of Sight Link.” Tubitak Press pp 153-160 Wireless Communication “Radio Propagation Models” Adebayo T. L. (2005); “Investigation on Coverage Level, Accessibility Index, and Propagation Path Loss Characteristics and Working of Power Received of GSM Signal.” A case Study of Benin City. Faculty of Engineering, University of Benin P.hD Seminar paper. Serdega G; Ivanovs G, (2005) “Estimation of Multipath Occurrence Factor in Lativia” Electronics and Electrical Engineering Kauna Technologija. pp90 – 92

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(ICERD08273) INVESTIGATION OF THE CHARACTERISTIC OF INDOOR RADIO PROPAGATION.

J.O EMAGBETERE, and F.O EDEKO Department of Electrical/Electronic Engineering, University of Benin, Benin-City. Email: [email protected]

The success of wireless local area networks (WLANs) has led to an intense interest among wireless engineers in understanding and predicting radio propagation characteristics within buildings.This paper present’s radio signal propagation measurement and modeling at 2.4GHz, within a building in the Faculty of Engineering, University of Benin. A base station built around SENAO access point, and a PA24 flat panel directional antenna of 19dBi gain and 17.50 beam-widths was setup for the experimentation. Signals were monitored using LINKSYS and NET STUMBLER version 4.0 software run on a Laptop, from the PA24 flat panel antenna. In this report, the effect of multi-path and delay spread is not considered.The result of the investigation reveals that the walls of the buildings attenuate the radio signal significantly with distance with a path loss exponent of 7.8 to 8.9 on the ground floor, and 2.9 to 5.2 for the 2nd floor. Keywords: Radio propagation, Indoor environment, Personal Communication System, Propagation Characteristic.

[ For the detailed document go to page 1522]

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

TECHNICAL SESSION 7A: SYSTEMS DESIGN AND ANALYSIS I

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968

(ICERD 08017) Dynamic modeling of multibody constrained mechanisms part I: rigid links robot Haladou A. (1), Maalej A.(2), Gorbel F. (3) (1)

Département de physique, Faculté des sciences, Université ABDOU MOUMOUNI, Niamey Niger, BP 10662, Tel (+227) 21793364 e-mail : [email protected] (2) LAboratoire de Systèmes Electromécaniques (LASEM), Ecole Nationale d’Ingénieurs de Sfax (ENIS), Route de Soukra -BP. W- SFAX 3038, Tunisie, Tel. (+216) 98411983- e-mail : [email protected] . (3) Department of Mechanical Engineering, Rice University, 6100 South Main Street, Houston, Texas 77251 1892, USA, e-mail: [email protected]

Abstract The method proposed is base on the computation of the dynamic equations of a collection of free rigid links, in the term of maximum generalized coordinates and then assembling the system by taking into account the joints holonomic constraints. The model is obtained in its reduced form, expressed in the term of only the controlled variables. Some difficulties usually presented in classical methods are deal with, such as: taking out of the non-working constraints forces and moments in the Newton-Euler method, the tedious calculation of derivatives in the Lagrange formalism. A reduced model for the spatial closed-loop robot of LASEM is developed and compared through numerical simulation to another model obtained with Lagrange constrained formalism. Key words: Dynamics, modeling, constrained mechanisms, rigid links. 1- Introduction Dynamic modeling of closed loop mechanisms with some kinematical constraints has long been the interest of many authors. The difficulties encountered depend upon the dynamical principle of the approach used: the introduction of the non-working constraints forces and moments between adjacent bodies by the Newton-Euler method [1], the tedious calculation of the reduced model of closed loop structures with Lagrange method using Lagrange multipliers [2-4]. Other methods were proposed to avoid these difficulties such as Kane’s approach, which gives the reduced model in the form that it can be generate automatically by computer [5]. However, when a structure presents some kinematics constraints, it becomes necessary to develop efficient mathematical procedures to reduce the model in its minimum degree of freedom. [6-7]. The method proposed here was valued for planar closed-loop mechanisms by Ghorbel and al. in [8]. In analyzing the planar mechanical system there are no much difficulties to study their kinematics. In Spatial kinematics requires more powerful tools. The main difference between the two analyses is the mathematical techniques to describe the angular orientation of rigid body, particularly because of the non commutatively of the rotational transformation. Many kinds of parameters are used, such as Euler angles, Cardan’s angles, Euler parameters and dual quaternion [1], [9]. This paper uses the Cardan’s angles to drive the holonomic constraints equations of the system with consideration that, in small displacement, the rotational transformation can be linearsed in the first order with a good precision. And the rotational transformations become commutative. The approach is then reformulated and compared with the Lagrange constrained formalism through the example of LASEM spatial closed-loop robot. 2- Constraint equations between adjacent bodies 2.1- Generalized coordinates

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria Pi

z0

u Pi

Gi

rpi

x0

yi

zi rGi ri

O

969

Oi xi

Ci y0 Figure 1: Location of a point in a rigid body

To locate a body in space, it is necessary to define a set of generalized coordinates that uniquely locate every point of the body. The R0(O0,x0,y0,z0) reference frame shown in figure 1, is a fixed inertial reference frame. Ri(Oi,xi,yi,zi) reference frame is a body Ci reference frame, which is fixed to the body Ci. Any point Pi of the body Ci can be located in Ri reference frame by the vector u Pi (R i )  O i Pi (R i ) , or by the vector in R0 reference. The origin of the reference Ri, Oi is located in R0 by the vector ri, so that rPi could be expressed as: rPi (R 0 )  O 0 Pi (R 0 )

rPi (R 0 )  ri (R 0 )  A i0 u Pi (R i )

(1)

A i0 is the orientation matrix of Ri attached to the body Ci with respect to R0. The matrix A i0 is expressed as a

function of the three Cardan’s angles i1, i2 and i3 for the orientation of Ci in R0. Thus, any rigid body Ci is located by a set of coordinates q 'i  i 1 , i 2 , i 3 , X Gi , YGi , Z Gi T called generalized coordinates, XGi,YGi,ZGi are the cartesian coordinates of the center of mass of the body Ci, in R0, define by the vector rGi  O0 G i .

2.2- Constraint formulation In an articulated mechanical system, the joint between two adjacent bodies can be described by kinematic constraints. a- Spherical joint: In a spherical joint at point P between two adjacent bodies Ci and Cj, the constraints in this joint are that the point P to be common to both bodies, given by the vector relation: (2)

Ö T  ri (R 0 )  rj (R 0 )  A i0 u pi (R i )  A 0j u pj (R j )

Relation (2) generates three algebraic translation holonomic constraint equations. It can be expressed as a function of the center of mass coordinates and the Cardan’s angles: Ö T  rGi (R 0 )  rGj (R 0 )  A i0 (u pi (R i )  u Gi (R i ))

(3)

 A 0j (u Pj (R j )  u Gj (R j ))  0

b- Revolute joint: A revolute joint between two adjacent bodies Ci and Cj is shown in figure 2. Qi

Ci

P uPi Oi

w i1 Qj

w i2

(Ri)

uPi

Cj

ri Oj

rj

z0 O0 x0

(Rj) y0

Figure 2: Revolute joint between 2 adjacent bodies Ci, Cj

It requires five algebraic equations (3 for translation and 2 for rotation). Three points are chosen on the common joint axes: P common to two bodies, Qi attached to body Ci and Qj attached to body Cj. The revolute joint required that point P should be common to both bodies and the vectors u i  PQi and u j  PQ j must be parallel [2]. Thus, point P must satisfy the spherical joint equation (3). pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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For translation holonomic constraints, let us consider the parallelism of vectors ui and uj, which means that the two vectors are collinear: (4)

ÖR  ui  u j  0

Where  is the vectors product operator. The relation (3) gives three algebraic equations. One can get the two remained constrain equations by chosen two orthogonal vectors wi1 and wi2, embedded in body Ci, such that u i  w i1  w i2 . Hence, the relation (4) is equivalent to u j .w i1  0 and u j .w i 2  0 , so that:  A i w (R ) T A j u (R )  0 0 i j i1 0 j  ÖR   T  A i0 w i2 (R i ) A 0j u j (R j )  0 

 

   

 

(5)

3- The Lagrangian’s constrained formalism Given a mechanism with a closed-loop chain, its dynamic model can be developed through the following steps [4-5]: * tree structure.

The closed-loop is cut at one of its passive joints to obtain a

* Then, the dynamic model of this tree structure is developed by using the unconstrained Lagrangian’s formalism as given by the generalized force (1) : Ã1 

d dt

 L  L       p q  q

(6)

Where L is the Lagrange function, q is the independent generalized coordinates used to describe the constrained system, and p is the non-conservative perturbation forces. * Next, the terms of constraints given by closing the loop are determined by using the Lagrangian’s multiplier. m

Ã2   ëk k 1

 Ök q

(7)

Where k are the m Lagrangian’s multipliers, Ö k  Ö k q 1 , q 2 ,..., q n   0 are the m implicit functions of constraint due to the closing of the loop and n is the number of degrees of freedom (d-o-f) of the system. * obtained by adding (6) and (7) :

Finally, the dynamic model of the constrained mechanism is (8)

à  Ã1  à 2

The component (i ) of () is given as: Ãi 

d  L  dt   q i

 L m  Ök     ëk (i=1, .., n) (9)  q  qi i  k 1

Or in the matrix form: Ã  D(q).q  [C(q, q )]q  G(q)  F(q, q )

(10)

Where: q   n , D(q)    nxn is the inertia matrix, [C(q, q )]   nxn is the centrifugal and Coriolis force matrix, n G(q)   n is the gravity vector, F(q, q )   is the exterior forces vector.

4- The approach proposed: Rigid links 4.1- Principle Given a constrained articulated system  with n d-o-f (figure 3), it can be decomposed, into: -A free system ’ with n’ d-o-f, described by (11), which consists of a collection of free (unconstrained) rigid-bodies. In this case, [D' (q' )] is constant and block diagonal, [C' (q' , q ' )] is null. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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- And some holonomic joint constraints (12). B

A = B =G C=D

A

C

G

D = E=F

A=B=G C=D E=F

+ E

F

Fn

Fn

Mn

Mn Constraints

Constraint system  Free system ’

Figure 3: The approach principle

The equation of motion of the free system ’ can be obtained by arranging the equations of motion of the free links in the classical dynamic form: ' : D'(q')q' + [C'(q', q ' )]q ' + G' (q') + F'(q', q ' ) = 0

Where: q' '

is the dependent

(11)

generalized

coordinates vector,

and

Ù'   n' ,

D' (q' )  n' xn' ,

n' [C'(q', q ' )]  n'xn' , G' (q' )   n' and F' (q' , q ' )   .

Consider now the constraints applied to the free system ’ and assume that we represent them with (n’-n) independent functions of holonomic constraints such that: (12)

Ö(q' ) = 0

 Ö



(q’) n’-n is at least twice continuously differentiable, so that  (q' )  is (n’-n) rank.   q'  With the introduction of the constraints (12) the generalized coordinates q’ are restricted to a subspace of ' , U’ so that: (13)

U' = q' Ù' : Ö(q' ) = 0}  Ù'

It follows from standard results in dynamics [1-2] that, the free system ’ (11), with the imposed constraints (12), has n d-o-f, and hence there exists n independent generalized coordinates q  , such that    n and the system (11) can be rewritten in a reduced form as follows (figure 4): (14)

 : D(q)q + [C(q, q )]q + G(q) + F(q, q ) = 0

In many situations, one may be able to choose the generalized coordinates that coincide with the variables of actuated joints, in which case the equations of motion (14) become:

D(q)q + [C(q,q )]q + G(q) + F(q,q ) = Ã

(15)

4.2- Reduced model formulation Using the given information of ’ (11) and the constraints (12), a systematic approach is formulated for the development of the reduced model of  in the following steps [8]:

Step 1: The independent generalized coordinates q with which we would like to describe the constrained system  can be chosen to satisfy the following twice continuously differentiable parameterization: á : U'   U   n

(16)

q'   q = á(q' )

Step 2: Using (12) and (16), we define :   Ø(q' )  Ö(q' )  0  Ø (q' , q) =   (17)     and Ø q' (q' ) =    q'   á(q' )  q 





Step 3: A set of coordinate V’ is defined such that:





V'  q' U': det[ Ø q' (q' )]  0  U'

(18)

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det designs determinant of the matrix. The system is said to be in a singular configuration when q' U' and q' V'. Hence V’ is the workspace region in q’ coordinates where the constrained system satisfies the constraints and in addition it is not in a singular configuration. Step 4: Using the implicit function theorem, for any given point q' V' , let Ø(q', q)  0 , there exists a neighborhood N q' of q' , and a neighborhood N q of q , such that: (19) (20)

q' = ó(q) and q ' = ñ(q' )q -1

0



Where ñ(q' ) = Øq' (q' )  (n'- n) n     I nn 

(21)

0(n’-n)n is an (n’-n)n null matrix, and Inn is an nn identity matrix. Then, the derivative of the vector q ' and the matrix ñ(q' ) are determined by: (22)

q' = [ (q' , q ' )] q  ñ(q' ) q -1   [ (q' , q ' )] = - Ø q' (q' )  q' (q' , q ' ) ñ(q' )      

(23)

Let W’  V’ denote the largest subset of V’ containing q’ for which the unique parameterization (19) holds. The corresponding domain of  is then denoted by . Step 5: Numerical computation of q'  (q) We are interested in numerically solving (17) Ø(q' , q)  0 , which has a unique solution q '  (q ) when q   as seen above. Since in addition the determinant det  q '  0 , and assuming that the domain W’ can be estimated with its boundaries, a numerical iterative algorithm, such as Newton-Raphson algorithm, can be set up such that for a given q   , a convergent solution q'  (q )  W' , with a given accuracy, can be obtained in a few number of iterations. Step 6: Reduced model Consider (12) with its differentiability properties, and express velocity and acceleration equations: [Ö q' (q' )] q '  0

(24)

 (q' , q ' )] q '  0 [Ö q' (q' )] q '[ q'

(25)

A standard result of classical dynamics [1-2], the constrained system can be completely described by the following algebraic differential equations:

D' (q' )q'[C' (q' , q ' )]q ' G' (q' )



 F' (q' , q ' )  Ö q' (q' )



(26)

T

ë

(27)

[Ö q' (q' )] q '  0

ë   n' is the vector of Lagrange multipliers and Ö q' (q')



 T ë the constraint generalized force vector.

The consideration of the virtual work W associated with the dynamics of the constrained system, due to a virtual displacement q’: äW  äq'T  D' (q' ) q'[C' (q' , q ' )] q ' G' (q' )



 F' (q' , q ' )  Ö q' (q' )

T ë

(28)



From (26), it is clear that W= 0 for any set of q’. And the virtual work of the generalized constrained force means that: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria äq'T Ö q' (q' )



T ë  0

973

(29)

T

äq' D' (q' ) q'[C' (q' , q ' )] q ' G' (q' )  F' (q' , q ' ))  0 (30)

From (20) we can note that,  (q' , q)  W' xÙ : (31) äq' = ñ(q' ) äq Combining (30) and (31) one can get: äq T ñ(q' ) T D' (q' ) q'ñ(q' ) T [C' (q' , q ' )] q



 ñ(q' )

T

G' (q' )  F' (q' , q ' )  0

(32)

Since the generalize coordinates q are independent:

ñ(q' ) T D' (q' )q '  ñ(q' ) T [C' (q' , q ' )] q ' T  ñ(q' ) G' (q' )  F' (q' , q ' )   0

(33)

From (20) and (21), the equations of motion of the constrained system in term of (q’, q) W’, is:

D(q')q + [C(q', q ' )]q + G(q') + F(q', q ' ) = 0

(34)

Where D(q') = ñ(q') T D'(q')ñ(q')

(35)

T

[C(q' , q ' )] = ñ(q' ) [C(q' , q ' )] [ñ(q' , q ' )] + ñ(q' ) T D' (q' )[ñ(q' , q ' )]

(36)

G(q') = ñ(q') T G' (q')

(37)

F(q', q' ) = ñ(q') T F'(q', q ' )

(38)

Replacing the computed q' , q ' and q' from (19), (20) and (22), the equation of motion of the constrained system (15) are finally expressed in term of the independent generalized coordinates q   . 5- Application to spatial a closed-loop robot The closed-loop robot of LASEM with five d-o-f is treated. It has a closed-chain structure as shown in figure 4. Five rotational servomotors drive it at joints O1,O2,O5,O6 and O7. The remaining joints are passive (O3,O4,O8:rotational) and (O9:spherical). R0(O0,x0, y0,z0) is a fixed inertial reference frame and, Ri(Oi, xi, yi, zi) is a body Ci reference frame. 5.1- Modeling The motion of each free link is described by the three Cardan’s orientation angles i1, i2, i3 and the three cartesian coordinates of its center of mass XGi, YGi, ZGi, with respect the fixed system of coordinate R0.  43

x4

x2

O9

q3 z3

O3 C4

C3

 63 O6

C2

 43

z6 x3

q4

C6 q6 O8 q 7= 73

z7, x 6

z4

q2= 23

C7

O 1, O 2, O5

z 2, z 5

O4 C5 q 5= 53

C1 O0

(a)

x5

z 1=z 0

O7

x1

x0 C0

q1= 13

x1

Figure 4: A 5 degree of freedom closed-loop robot

The equations (11) are obtained by assembling the knowing equations of motion of seven free links: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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q'  [11 , 12 , 13 , X G 1 , X G 2 , X G 3 , ...,  71 ,  72 ,  73 , X G 7 , X G 7 , X G 7 ]  Ù'   42

D' (q' )  diag

(i)

I(1) , m1 , m1, m1, ..., I(7) , m7 , m7 , m7  42 x 42 I

(i=1,7), [C' (q' , q ' )]  0   equations

42 x 42

, F' (q' , q ' )  

42

is the link Ci inertia moments matrix, mi the Ci mass

G' (q' )  [0, 0, 0, 0, 0, m 1 g,...,0, 0, 0, 0, 0, m 1 g] T   42

Constraints

n’=42 and n=5, the number of the independent constraint equations Ö(q' )  0 , is (n’-n)=37. -Translational holonomic constraints: The relation (3) is used to compute the translational holonomic constraints equations of each joint: Link Ci

Link Cj



T



T

rGi (R o )  X Gi , YGi , Z Gi  T

rGj (R o )  X Gj , YGj , Z Gj

u pi (R i )   ç Pi , î Pi , ò Pi  T

u pj (R j )  ç Pj , î Pj , ò Pj

u Gi (R i )   ç Gi , î Gi , ò Gi  T

u Gj (R i )   ç Gi , î Gi , ò Gi  T

A 0k in (3), is expressed in term of the third Cardan’s angles, using the Denavit-Hartenberg classical

convention [2]. Thus, one can get, with: La k  O k G k , Lb k  G k O k 1 ,

Joint O0 : between C0 and C1





ÖT  X G 1  0; YG 1  0; ZG 1  La1  0

Joint O1 = O2: between C1 and C2 X  X  La 2 cos  cos   0 G1 13 23  G2 Ö T   YG 2  YG 1  La 2 sin 13 cos  23  0  Z  Z  Lb  La sin   0 1 2 G1 23  G2

And so on, for joints O3, O4, O5, O6, O7, O8 and O9. - Rotational holonomic constraints: the relations (5) are used, with the following links parameters: Link Ci

Link Cj

ui(R i)  w i1(R i)  w i2(R i) w i1(R i )  wi2(R i) 

 çwi 1,  çwi 2,

î wi 1, ò wi 1 

î wi 2, ò wi 2 

T



u j (R j )  ç uj , î uj , ò uj

T

T

Joint O0: between C0 and C1





Ö R  11  0; 12  0

Joint O1 =O2: between C1 and C2 cos 13 sin  22  sin 13 sin  21 cos  22  0 ÖR   cos  21 cos  22  0 

Idem at joints O3, O4, O5, O6, O7, O8 . Thus n’-n= 38 instead of 37. Since the loop of the structure is plan, the 3 translational constraints equations of a passive joint, can be replaced by the 2 translational closing constraints equations of the loop [10]. For this example, the 2 equations are: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

975

Ö T   33   53  ð  0;  43   23  ð  0

Finally, holonomic constraints equations Ö(q' ) = 0 can be formulated as in (12). Parameterization equations (16): are expressed as a function of the third absolute Cardan’s angle of each active link Ci with respect to fixed reference R0, so that it coincides with the actuated variable qi. The actuated links C1,C2,C5,C6,C7 are parameterized as: T

q  q 1 , q 2 , q 5 , q 6 , q 7 

 13 ,  23 , 53 , 63   33 , 73 T

With the computed constraints equations and the chosen parameterizations, the relations (17) are determined. Reduced model formulation: The reduced model is generated, when its domain of validity (18) : V'  q' U': 33  33  k , k  Z Or V'  q   : q2 - q 5  k , k  Z

5.2- Numerical simulation A robust control low proposed in [10] is used to simulate and compare the two models developed [12] with Lagrange method and the approach proposed: Ã c  D(q) qd  Kv  (qd  q)  Kp  (q d  q)  C(q, q )q  G(q)  F(q, q )

(39)

[Kv],[Kp] are diagonal constant matrixes, q d is the desired articulated variable. The material properties: mass density 4.24 E 3 Kg/m 3 ,Young modulus 7.5 E9 N/m 2 . The links dimensions are reported as follow: Link Length(m) Diameter (m) C1 L1=0.25 D1=0.05 C2 L2=0.40 D2=0.03 C3 L3=0.62 D3=0.03 C4 L4=0.40 D4=0.02 C5 L5=0.20 D5=0.05 C6 L6=0.15 D6=0.03 C7 L7=0.15 D7=0.03 The payload mass is mc=0.050Kg. LASEM robot limits articulation joint angles are : -160o  q1 160o ; 36o  q2  158o ; - 74o  q3 38o ; -70o  q4  70o ; -45o  q5  25o ; -70o  q6  70o ; -180o  q7  180o Parameters simulation : Kv (i,i)=200 ; Kp(i,i)=1000 (i=1, 2, 5, 6, 7). The desired joint velocity chosen is the classical Bang-Bang trapezoidal as chow in figure 5 [12]. q d

0 t Figure 5 : desired joint velocity

Initial angle velocities: q di  0 (i = 1, 2, 5, 6, 7) ; Initial angle positions: q d1 - 2 ð/ 3 ; q d 2 = ð/ 4; q d5 = - ð/ 3; q d6  - ð/ 3; q d7 = - ð/ 2 Final: angles positions : q f 1 = 2 ð/ 3; q f 2  3 ð/ 4; q 5 = ð/ 8; q f 6 = ð/ 6; q f 7  ð/ 2 Maximal desired velocity and acceleration : pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria q di  1.5 r a d/s ; q di  1 r a d/s 2

976

(i = 1, 2, 5, 6, 7)

Simulations results show in figures 6 to 9 give good agreement between Lagrange method (qLi) and method proposed (qai) (i=1,2,5,6,7). The few differences are certainly given the numerical errors in calculations. 1,2

2,5

1,0 angle (rad)

angle (rad)

2,0

0,8 0,6 qL1 0,4

qa1

qL2 1,5

qa2

1,0

0,2 0,0 0,0

0,5

1,0

1,5

2,0

Figure 6 : angular position at joint O1

2,5 time (s)

3,0

0,5 0,0

0,5

1,0

Figure 7 : angular position at joint O2

1,5

2,0

2,5 time (s)

3,0

1,2

angle (rad)

1,0 0,8 qL5

0,6

qa5

0,4 0,2 0,0 0,0

0,5

1,0

1,5

Figure 8 : angular position at joint O5

2,0 2,5 time (s)

3,0

1,2

angle (rad)

1,0 qL6

0,8

qa6

0,6 0,4 0,2 0,0

0,5

1,0

1,5

Figure 8: angular position at joint O6

2,0 2,5 time (s)

3,0

1,2

angle (rad)

1,0 0,8

qL7 qa7

0,6 0,4 0,2 0,0 0,0

0,5

1,0

Figure 9 : angular position at joint O7

1,5

2,0

2,5 time (s)

3,0

6- Conclusion The paper proposes a validation of the approach for dynamic modeling of spatial closed loop robot by adaptation cardan’s angle and linearising the rotational transformation to solve their non commutatively. Since the approach is a matrix formulation, the problem of the eliminating of the nonworking constraints in the Newton-Euler approach and the tedious calculations in the Lagrange formalism are resolved.

References [1] Parviz E. Nikravensh, ‘‘Computer-Aided Analysis of Mechanical Systems’’, Prentice Hall, Englewood Cliffs, New Jersey, 07632- 1988. [2] Megahed S., ‘‘Contribution à la modélisation géométrique et dynamique des robots manipulateurs à structure de chaîne cinématique simple ou complexe‘‘, thèse de doctorat. Université de Toulouse (France) 1984. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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[3] Max Giordano, “Méthode d’obtention d’un modèle dynamique de robots en chaîne complexe’’, R.A.I.R.O APII, Vol. 21 1987 pp. 151-173. [4] Miller K., Warsaw and Clavel R., Lausane, ‘‘The Lagrange-based model of delta-4 robot dynamics’’, Roboter system -Springer-Verlag 1992.

[5] T. R. Kane and D. A. Levison, “Dynamics: Theory and applications”, Mc Graw-Hill, New York (1985). [6] R. L. Huston and J.T Wand, “Kane’s equations with undetermined multipliers: application with constrained multibody systems”, ARO Symposium, Kinematics and Dynamics of Robot Manipulators, API (1985). [7] Farid M. L. Amirouche and Tongyl JIA, “Automatic Elimination of the undetermined Multipliers in Kane’s equations using a pseudo uptriangular decomposition method”, In. J. of Computers and Structures Vol. 27 pp. 203-210, 1987. [8] Ghorbel F., Chetelat O., Lonchamp R., ‘‘ A reduced model for constrained rigid bodies with application to closed-loop robots‘‘, Proceedings of the 4th IFAC Symposium on Robot Control (SY. RO. CO. 94)Capri, Italy, September 19-21, 1994. [9] Edward J. Haug, ‘‘Computer Aided Analysis and Optimisation of Mechanical System Dynamics’’, Springer- Verlag Berlin Heidelberg, 1984. [10] Khalil W., Liégeois A., Fournier A., ‘‘Commande dynamique des robots ‘‘, R.A.I.R.O. Automatic/Systems Analysis and Control, Vol. 13, No 2, 1979 pp. 189-201. [11] Maalej A., ‘‘Application of DYNASIM Simulation to Engineering Problems’’, Journal of Advances in Modeling and Analysis-B, Vol. 24, N4, pp 1-12, 1992. [12] Haladou A.., ‘‘Contribution au développement d’une nouvelle approche de modélisation dynamique des robots manipulateurs à éléments rigides et flexibles : en vue de leur commande’’, thèse de doctorat, Ecole Nationale d’Ingénieurs de Tunis, 2002 Tunisie.

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978

(ICERD 08018) Dynamic modeling of multibody constrained mechanisms part II: Flexible links robot Haladou A. (1), Maalej A.(2), Gorbel F. (3) Département de physique, Faculté des sciences, Université ABDOU MOUMOUNI, Niamey Niger, BP 10662, Tel (+227) 21793364 e-mail : [email protected] (2) LAboratoire de Systèmes Electromécaniques (LASEM), Ecole Nationale d’Ingénieurs de Sfax (ENIS), Route de Soukra -BP. W- SFAX 3038, Tunisie, Tel. (+216) 98411983- e-mail : [email protected]. (3) Department of Mechanical Engineering, Rice University, 6100 South Main Street, Houston, Texas 77251 1892, USA, e-mail: [email protected] (1)

ABSTRACT The part I, of these two-part articles, presents an approach for dynamic modeling of multibody constrained mechanisms with rigid links. In this second part, the method is extended to constrained mechanisms with flexible links. The finite element method is used to take account the flexibility effect of the links in the system dynamic. The principle of the method steals the same as in the part I. The equations of motion of a collection of free links are first computed and, the system is assembled by introducing the joints holonomic constraints and the boundary conditions of the flexible links. The reduced model is finally expressed in term of controlled variables and finite elements node displacements. An example of five-degree of freedom closed-loop robot with one flexible link is treated.

Key words : Dynamic, modeling, constrained mechanisms, flexible links 1- Introduction It’s well known that mechanical systems working at high speed generate small oscillations due to the elasticity of the elements material. In current design applications, heavy structural elements are used to combat bending effects of links. Numerous authors have commented on the performance limitations in the achievable accuracy of manipulators, when these assumptions are considered. There is considerable interest in designing light robot manipulators, with high capacity of moving larger payloads without increasing the mass of linkages. The dynamic of flexible robots manipulators is generally described by two coupled sets of generalized coordinates. One set of variables defines the dynamic of nominal motion of rigid links. The second set describes the deviations from the nominal motion due to the elements flexibility. These second variables are assumed to represent small motions in the sense of vibration modes. The deviations are usually described by partial differential equations, which represent the vibrational motion of continuum bodies [1]. However, many difficulties appeared when solving such equations with infinite dimensions. To gain computational efficiency, some techniques are used to reduce the number of equations and associate them with those methods for rigid bodies’ nominal motion: Lagrange assumed mode method [2-3], Lagrange finite element method [4], joint co-ordinates method [5-6]. In this paper, an approach of dynamic modeling of multibody constrained mechanisms proposed in [7-8] is extended to flexible links structures. The finite element method is associated to describe the flexibility motion of links. For the example of a five-degree of freedom closed-loop robot considered, only one link is assumed flexible for illustration.

2- Constraint equations 2.1- Generalized coordinates For locating a body in space, we define R0(O0,x0,y0,z0) as fixed inertial reference frame shown in figure 1, and Ri(Oi,xi,yi,zi) a reference frame attached to the body Ci. a- Rigid state [8]: At each node Pi of the body Ci is associated a reference frame RPi(Pi,xi,yi,zi) called nodal reference. The point Pi can be located in R0 by the vector rPi as: rPi (R 0 )  ri (R 0 )  A i0 u Pi (R i )

(1)

Ai0 is the orientation matrix of Ri with respect to R0 and expressed as a function of three Cardan’s angles

i1, i2, i3. The rigid state Ci is located by a set of Lagrange generalized coordinates q 'i  [ i1 ,  i 2 ,  i 3 , X Gi , YGi , Z Gi ] T . XGi, YGi and ZGi are the cartesian coordinates of the center of mass of the body Ci in R0. q'i is the nominal motion’s vector. b- Flexible state: When the deformation of the body is considered the nodal reference frame RPi will be displaced to a new nodal reference frame R *Pi ( PPi* , x*Pi , y *Pi , z *Pi ) [2]. This displacement is consisted of two pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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infinitesimal vectors: translation of the node Pi d Pi  [dxi , dyi , dzi ] T and, rotation of the reference frame RPi ä Pi  [ä  xi , ä  yi , ä  zi ] T

.

The orientation of the nodal reference frame R *Pi with respect to RPi is given by the differential orientation matrix EPi and, the global orientation matrix * A0Pi with respect to R0 : E Pi

*

 1    ä  zi  ä  yi 

 ä  zi 1 ä  xi

ä  yi    ä  xi  1 

(2)

A 0Pi  A i0 E Pi

(3)

The position of the new node *Pi, is given by : *

rPi R 0   ri R 0   A i0 u Pi R i   *A 0Pi .d Pi R i  (4)

And when the point *Pi is confounded to the center of mass *Gi, relation (4) becomes: *

r*Gi R 0   rGi R 0   A i0 . u Gi R i   * A 0Pi .d Pi R i 

(5)

A flexible body *Ci is then located by the vector of generalized coordinates * q'i : q'i [* i 1 , *i 2 , * i 3 ,* X Gi ,* YGi , * ZGi ]T

(6) *

*

i1, *i 2 , *i 3 are the new Cardan’s angles of the link Ci:

*

 i1   i 1  ä  xi ,*  i 2   i 2  ä  yi , * i 3  i 3  äzi

*

X Gi ,* YGi ,* ZGi are the new cartesian coordinates of Gi.

(7) *

Pi

uPi

Ci Gi

dPi *

Pi

rPi z0

zi xi

rPi ri

(R0)

Oi

yi (R0)

*

O0 x0

*

Gi

*

Ci

y0

Figure 1: Location of a node in flexible body

2.2- Constraint equation of revolute joint A revolute joint between two adjacent flexible bodies Ci and Cj is shown in [8]. It requires five algebraic holonomic constraints equations since it allows one degree of freedom. a- Rigid state: The revolute joint requires that point P should be common to both bodies and the vectors u i  PQ i and u j  PQ j must be parallel [8]. For translational constraints equations constraints, the point P is common to Ci and Cj and expressed as a function of the center of mass coordinates and the cardan’s angles: Ö T  rGi  rGj  A i0 (u Pi (R i )  u Gi (R i ))  A 0j (u Pj (R j)  u Gj (R j ))  0

(8)

The rotational constraints equations are given by :  A i w (R ) T A j u (R )  0  0 i1 i j 0 j ÖR   T i j  A 0 w i2 (R i ) A 0 u j (R j )  0

 

 

 

(9)

u i  w i1  w i2 and  is the vectors product operator.

b- Deformed state: The joint between two bodies is assumed non distortional, only the deformations of the links are taking account. Translational constraints equations (8) become: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria *

Ö T  * r*Gi (R 0 )  * r*Gj (R 0 )  0

980

(10)

Rotational constraints equations (9) become: *

  ÖR    

*

Pi 0

w i1 (R i )

*

Pi 0

w i2

A A

T *

A 0Pj u j (R j ))  0

T *

A 0Pj u j (R j ))  0

 (R )  i

(11)

3- The approach proposed: flexible links Let us consider a constrained articulated mechanical system * with flexible bodies (figure 2). * is assumed with nr degree of freedom (d-o-f) for the nominal motion. By using the finite element method, any *Ci flexible body is decomposed into serial finite elements [4] with nfi d-o-f. 3.1- Principle *  can be decomposed into: - A free system *’ with n’ d-o-f , which consists of collection of free flexible links. - And some joint holonomic constraints and boundary conditions of flexible links. Finite element A = B =G C

C=D

B

A

G

D

Fn

=

+ E

E=F

Fn

Mn

A=B=G C=D E=F …

F *

Constraint system 

Free system *’

Mn

Cnstraints

Figure 3: The approach principle

The equation of motion of *’ is formulated in the classical

dynamic form: *

Ó' : * D'(* q' ) * q' + * C'(* q',* q ' ) * q '





*

*



*



*



+ K'( q' ) q'+ G'( q' ) F'( q',* q ' ) = 0



*

*

*

*

(12)

q'  [q' r , q' f ]T is a dependent generalized coordinate vector consisting of two sub-vectors q'r which describe

the nominal motion of rigid bodies and, q'f for the node displacement of finite elements; [* D'(* q' )] n' xn' is the inertia and mass matrix; [* C'(* q',* q ' )] n' xn' is the centrifugal and Coriolis force and dump matrix. * * n' * * * n' [* K'(* q' )]   n' xn' is the stiffness matrix and G'( q' )   is the gravity vector and F'( q', q ' )   is the exterior forces vector. The equation (12) is expressed explicitly as:  D 'r (q 'r ) 11  0 





 q 'r    D 'f (q 'f ) 22  q 'f  0

 C (q , q )   ' r

' r 11

0

 0  0

' r



0 C 'f



(q 'f , q 'f

 q 'r     ) 22  q 'f 



(13)

 q 'r  G 'r (q 'r )  Fr' (q 'r , q 'r )  0  ' ' '      K 'f (q 'f )  q '   0  Ff (q f , q f ) 0  f 0





For the nominal motion, the inertia matrix [D'r (q'r )]11 is constant and formed of diagonal blocks, and the centrifugal and Coriolis matrix [C'r (q'r ,q r' )]11 is null. Now consider the constraints applied to the free system *’ and assume they can be represented by (n’-n) independent functions such that: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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 Ö (q' )  0 Ö(* q' )   r r     Ö f (q'f ) 0

(14)  *Ö

 (* q' ) *   q' 

Where * Ö  n'  n is at least twice continuously differentiable, so that  '

Ö r (q'r )   n r

and flexible bodies.

'

Ö f (q'f )   n f

U' = * q'  *' : *(* q' ) = 0



has a rank of (n’-n).

are respectively the joint constraints and the boundary conditions of the

With the introduction of the constraints (14) the generalized coordinates * Ù' so that: *

981

* '

*

q'

are restricted to * U' subspace of

(15)

From standard results in dynamics we know that the free system *’ (12), with the imposed constraints (14), has n d-o-f, and hence, there exists n independent generalized coordinates * q* Ù, such that *    n and the system (12) could be written in a reduced form as follows: *  : [* D( * q)]* q +[ * C( * q,* q )]* q + * G( * q)+ * F( * q,* q ) = 0 (16) [* D(* q)]   nxn , [* C(* q,* q )]   nxn , * G( * q)   n

*

F(* q,* q )   n

The generalized coordinates are chosen to coincide with the variables of actuated joints so that (16) is written as: * (17)  : [* D( * q)]* q +[ * C(* q,* q )]* q + * G( * q)+ * F( * q,* q )= *  *

  n

is the applied generalized force vector of the n actuators. The equation (17) can be expressed explicitly :  * D(q , q ) 11 r f   * D(q , q ) r f 21 

 

*

  D(q , q )   D(q , q ) r

f

r

f

*

 q  r    q e  22 

12 

* [ * C(q , q , q , q )]  r , q f , q f )]12  q  r r f f 11 [ C(q r , q   r *  q  * [ C(q r , q r , q f , q f )]21 [ C(q r , q r , q f , q f )] 22   f 

0  0

*

q r [ (1) q r, (2) q r, ...,(n r ) q r ] T is

the

generalized

independent

18

0  q r   * G 1 (q r , q f )   * F1 (q r , q r , q f , q f )  Ã r       K f  q f   * G (q , q )  * F (q , q , q , q )  0   2 r f   2 r r f f 

 

coordinate vector for the nominal motion and q f

[ (1) q f , (2) q f , ..., (nf ) q f ] T represent

the nodal generalized

independent coordinates for flexible bodies, where (i) q f (i = 1, m) is the sub vector of nodal generalized independent coordinates relatively to the flexible body *Ci such that (i) q f [ (i) q f 1, (i) q f 2, ...,(i) q fNi, ] T , Ni is the nodal d-o-f of the flexible body Ci. 3.2- Reduced model formulation With the given information on the free system * ' and the constraints (14), a systematic approach for the development of the reduced model of * is summarized in the following steps: Step1: The independent generalized coordinates *q with which we would like to describe the constrained system * (17) can be chosen to satisfy the following twice continuously differentiable parameterization: *

 : * U'  * U   n *

(19)

q'  * q = * ( * q' )

Step 2: Using the constraint equation (18) and the parameterization (19), we define the following relations: *

 *  (* q' )  0   (* q',* q) =  * *    *   ( q' )   q 

and

 * *  *     ( q' )  *  ( q' ) = * q '    * q'   

(20)

Step 3: A set of coordinate *V’ is defined as: *

  V'   * q'* U': det  * Ø *q' (* q' )   0  * U'    

(21)

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The system is said to be in a singular configuration when * q'  * U' and * q'  * V'. Hence, *V’ is the workspace region in *q’ coordinates where the constrained system satisfies the constraints and in addition it is not in a singular configuration. Step 4: For any given point * q'  * V' , let * Ø(* q',* q' )  0 . Using the implicit function theorem, we can conclude that there exists a neighborhood * Nq' of * q' , and a neighborhood * Nq of * q , such that: *

q' = *ó( * q)

*

*

*

(23) (24)

*

q ' =[ ñ( q' )] q

  q ' =  * ñ(* q',* q ' ) * q  * ñ(* q' ) *q    

* 





-1

 ñ( q' ) =  Ø *

*

*

*

q'



 (* q' )  

(25)

0 (n'- n) xn     I nxn 

(26)

-1         * ñ( * q',* q ' )  = -  * Ø *q' ( * q' )   * Ø * q' ( * q',* q ' )  * ñ( * q' )          



(27)

Let W’  *V’ denotes the largest subset of *V’ containing *q’ for which the unique parameterization (23) holds. The corresponding domain of  is then denoted by *. Step 5: Numerical computation of * q'* ó(* q) We are interested in numerically solving (21) *

*

 (* q',* q )  0 , which has a unique solution

*

q'* ó(* q)

when

*

*

as seen above. Since in addition the determinant det( Ø *q' )  0 , and assuming that the domain W’   can be estimated with its boundaries. A numerical iterative algorithm, such as Newton-Raphson’s, can be set up such that for a given * q  *Ù , a convergent solution * q'* ó(* q)  * W' , can be obtained with a given accuracy. Step 6: Reduced model If we consider the equation (14), with its differentiability properties, the equations of velocity and acceleration are such that: q Ù

*

[* Ö *q' (* q' )] * q '  0

(28)

 (* q',* q ' )] * q '  0 [* Ö*q' (* q' )] *q'[*  *q'

(29)

*

 can be then completely described by the following differential equation obtained from using (12) and (28): [ D'(* q ' )] * q'[ * C'(* q',* q ' )] * q ' * K'(* q' ) * q'





 * G'(* q' )  * F'(* q',* q ',* q' )  * Ö *q' ( * q' )



T *



(30) ë

[* Ö*q' (* q' )] * q '  0 *

  n'

(31)

is the vector of Lagrange multipliers and

[* Ö*q' ]T * ë

is the constraint generalized force vector. The

*

virtual work W associated with the dynamics of the constrained system, due to a virtual displacement *q’ is given by: *

äW * äq' T [* D'(* q' )] *q'[* C'(* q',* q ' )] * q



*

*

*

[ K'( q' )] q'* G'(* q' ) * F'(* q', q ' ) [* Ö*q' (* q' )]T *ë



(32)

From (32), it is clear that *W= 0 for any set of *q’. And the virtual work of the generalized constrained force means that: *

*

ä q' T

äq' T *

*

T *

*

 Ö ( q' ) ë  0 [ D'( q' )] q'[ C'( q', q ' )]

(33)

* q'

*

*

*

*

*

*

*

*

*

*

*

*

*

*

q'



(34)

[ K'( q' )] q' G'( q' ) F'( q', q ' )  0

From (24) we can note that: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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 (* q',* q)  * W'  *  :

äq' = [ * ñ( * q' )] * äq

983

(35)

Combining (33) and (34) one can get: *

T  äq T  * ñ( * q' ) 



*

*

*

*

T *

*

*

*

*

  D'( q' ) q' ñ( q' ) [ C'( q', q ' )] q ' Since the coordinates q are independent:    ñ( q' )   K'( q' )  q' G'( q' )  F'( q', q ' )   0 (36)  *

T

*

*

*

*

T *

*

*

*

*

*

*

*

*

*

T *

*

*

*

*

*

*

*

 ñ( q' )  D'( q' ) q' ñ( q' ) [ C'( q', q ' )] q ' (37)   ñ( q' )  K'( q' ) q' G'( q' )  F'( q', q ' )   0 *

T

*

*

*

*

*

*

*

The equations of motion of the constrained system in term of (*q’, *q) *W’*, become: [* D(* q' )] * q [* C(* q',* q ' )].* q

(38)

+[* K(* q' )]* q+* G(* q' ) * F(* q',* q ' ) = 0 *

*

*

*

*

T *

*

*

*

*

 D( q')=  ñ( q')  D'( q') ñ( q') *

*

*

T *

*

*

(39)

*

*

[ C( q', q' )] =[ ñ( q')] [ C'( q', q' )][ ñ( q')] + * ñ(* q')



T *

*

*

*

(40)

*

  D'( q')[  ( q', q ' )]  K( q')=  ñ( q')  K'( q') ñ( q') G( q' ) =  ñ( q' ) G'( q' ) F( q', q ', q' ) =  ñ( q' ) F'( q', q ' ) *

* *

*

*

*

*

*

*

*

T *

*

*

T *

*

*

*

*

*

(41)

*

T *

*

(42)

*

(43)

Finally, when replacing the computed expressions of * q' , * q ' , *q' relations (23), (24) (25) the reduced model (17) of the constrained system is obtained in the term of the independent generalized coordinates q 4- Application to a spatial closed-loop robot: The closed-loop robot with 5 d-o-f as shown in figure 4. R0(O0,x0,y0,z0) is the inertia fixed coordinate system, Ri(Oi,xi,xi,zi) is the systems of coordinates fixed to the link Ci (i=1,2, …,7). Only the second part (O3O6) of the link C3 is assumed flexible. The references R6(O6,x6,y6,z6) and R7(O6,x6,y6,z6) attached to the links C6 and C7 become respectively R*6(O*6, x*6, y*6, z*6) and R*7(O*7, x*7, y*7, z*7). To simplify the problem, only the flexion in the plan (x3, y3) is considered (figure 5) and, the payload which is not represented here is a concentrated mass mc. x4

 33 x2 O9 q3 z3

C4

C3

63

*

O6

z6

E

C3

C2

6

q6

53

O*6

x3 O7 O8 C7 q7=53 z7=x6

O3

z1=z0

q6

q4

x5

z4

O *7

q2= 23

x*3

O4

C5

z2=z5

O *8

q5=53

z*7

O1=O2 =O 5

C1 O0

x1

q1=13

x1

x0 C0

Figure 4: A 5 d-o-f closed-loop robot with on flexible link

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x2 q3 O3 O6

x3

z29 y2

dy29

Finite element

*

x*3

O6

y3

Figure 5: Flexible link C3 in plan (x3, y3)

4.1- Modeling The flexible link C3 is assumed clamped to a rigid base at point O2 and free at O6, the number of finite elements is limited to 8. The relation (13) for the free system *’ consisted of 7 links is written with: q 'r [* 11 ,* 12 ,* 13 , * X G 1 ,* YG 1 ,* Z G 1 , ..., *

 71 ,*  72 ,*  73 , * X G 7 ,* YG 7 ,* Z G 7 ] T   42

q 'f  [dy31, äz31, dy32 , äz32 ,..., dy38 , äz38 , dy39 , äz39 ]T  R18

dy3i and z3i represent respectively the nodal displacement of the node 3i (i=1, 9) and the rotation of the cross section of the flexible link C3. (i) [D 'r (q 'r )]11  diag I (1) , m1 , m1 , m1 , ... , I (7) , m 7 , m 7 , m 7   4242 I is the matrix of the moment inertia of the link Ci in the space. [C'r (q 'r , q 'r )]11  0   42 42 G 'r ( q 'r )  [0, 0, 0, 0, 0, m1 g, ....,0, 0, 0, 0, 0, m 7 .g]T   42 [D'f (q 'f )]22  1818 and [K 'f (q 'f )]22  1818 are obtained respectively by assembling the elementary flexion matrix of each element i Dfi  44 and Kfi  44 such that: [D'f (q 'f )] 22   a Tf [D'f, i ] a f ; [K 'f (q 'f )] 22   a Tf [K 'f, i ] a f i

af is the location matrix of the finite element.

i

[C 'f (q 'f , q 'f )]22  1818 can be chosen to satisfy the Raleigh linearization condition: [C' (q 'f , q 'f )]22  â1 [D' (q 'f )]22  â 2 [K 'f (q 'f )] 22

Ff' (q 'f , q 'f )  diag0, 0, 0, ..., 0, 0, mc g, 0  18 the gravity vector of the payload mcg.

Constraint equations The free system has d-o-f is n’=60 ( n 'r  42 , n 'f  18 ). For the constrained system: nr=5 (5 actuated joints) nf=16. Then the total number of the constraint equations is n’-n=39 and, are obtained from (10), (11) and the following boundary conditions: dy 31  0 ; äy 31  0 Parameterization The parameterizations (19) are chosen to coincide with the actuated joint parameters for the nominal motion: q r  q1 , q 2 , q 5 , q 6 , q 7  T  [13 , 23 , 53 , 63  33 , 73 ]T Nodes

 [dy32 , äz 32 , dy 33 , äz 33 , dy 34 , äz 34 , dy 35 , äz 35 ,

q f   q 8 , q 9 , q10 , q11 , q12 , q13 , q14 , q15 , q16 , q17 , q18 , q191 , q 20 , q 21 , q 22 , q 23 , q 24

displacement parameters are chosen as:

T



dy 36 , äz 36 , dy 37 , äz 37 , dy 38 , äz 38 , dy 39 , äz 39 ] T

Reduced model The reduced model is then obtained by relation (17). 4.2- Numerical simulation and discussion The main difficulty to control flexible manipulators is that the classical control laws act only on the joint variables and, cannot be used for the other variables of the flexible motion. To solve this problem, some composite control laws are proposed in the literature. Most of these papers present the same strategy: the model of flexible robot manipulators is decomposed into two parts. The first part called slow model which describes the nominal motion of the rigid system with the effect of the deformation of bodies. The second part called fast model describes the small oscillations of the system due to the flexibility of the links. An independent control law for the small model, called slow controller is first designed using any classical control laws. Second, a fast controller is designed, for the fast model using other kinds of new control pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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theories. The method used here is proposed by Yoshifumi Morita [9], which is based on the integral manifold approach theory. A classical predictive nonlinear decoupling control law is used for the slow model and, the fast controller is designed for the fast model on the basis of H control theory (figure 6), such that the composite control law is given by: (45) Ã  Ãs  Ãf Ãs 

*

 D(q ) r

11

q d  Kv  (q d  q r )  Kp  (q d  q r )

     * C(q r , q r )  q r  * G 1 (q r )  * F1 (q r , q r )   11

à f  k f 

dz

(46)

(47)

dt

s is the slow control low and represents a bloc that control the nominal motion [8], [Kv] and [Kp] are diagonal constant matrixes, q d q d, q d are the desired articulated position, velocity and acceleration. A good choice of the gains Kp(i,i) and Kv(i,i) for each servomotor i, defines its own dynamics independently of the other actuators and the configuration of the robot manipulator. For this example, the values of those gains are Kv(i, i)  200 and Kp(i, i)  100 0 . f is the fast control law, [kf ] is a diagonal constant matrix, and z is variable that defines the manifold deviation of the flexible links, at the reduced time t such that t  t /  (t is the real time and  is a small scalar). Only the case of the elasticity is considered. The numerical tool used is the numerical dynamic simulator DYNASIM [10]. The material properties: mass density 4.24 E 3 Kg/m3 ,Young modulus 7.5 E9 N/m 2 . The links dimensions are reported as follow: Link Length(m) Diameter (m) C1 L1=0.250 D1=0.050 C2 L2=0.400 D2=0.030 C3 L3=0.6200 D3=0.030 C4 L4=0.400 D4=0.020 C5 L5=0.200 D5=0.050 C6 L6=0.150 D6=0.030 C7 L7=0.150 D7=0.030 The payload mass is mc=0.100Kg. The fast control low is chosen the be limited to the first order one, so that the matrix [kf] is null. The control becomes as for the rigid system. Maximal joint velocity and acceleration: q di  1.5 r a d/s ; q di  1 r a d/s 2

(i = 1, 2, 5, 6, 7)

Results of simulation are reported in figures 7- 9. in figure7 is reported the desired and the real end efector trajectories. The displacement q20 (node 9) is reported in figure 8 and shows the effect of the flexibility of the body C3 on the end-effector precision. It describes the small oscillation of the structure and deviation between the trajectories. And in the figure 9 are represented the deviation of the end effectors coordinates from the desired ones. The results shows that the Z coordinate is more affected by the deflection, this is true since only the flexibility in plane (x3,y3) is considered. 5. Conclusion An approach for dynamic modeling of multibody constrained mechanisms proposed in part I for rigid body systems, is extended in this paper for flexible links robot. The finite element method is used for modeling the deviation of flexible elements from the nominal motion. The principle or the approach steals the same as for rigid body system. Only the deformation effect is added to the dynamic of the system.

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qr

qd q d

e

e

*

[Kp]

986

G 1 (q* )

qr *

 D(q )

[Kv]

r

s

r

11

Robot q r

qd

*

f

F1 (q r , q r )

dz

q r

*

 C(q , q ) r

dt

r 11

[kf]

Figure 6: Control block scheme for the composite control low. 0.0 0.040

2.0

4.0

6.0 time(s)

0.020

0,020

error (m)

deflexion (m)

0,040

0,000

0.000 -0.020

time (s)

-0,020

Zer Xer Yer

-0.040

0,0

2,0

4,0

Figure 8: displacement node q20

6,0

Figure 9 : The deviations of end effector’s coordinates from the desired coordinates

Reference [1] Yoo W. S., Haug E. J. ‘‘Dynamics of flexible Mechanical Systems Using Vibration and Static Correction Modes’’, Transactions of the ASME, Journal of Mechanisms, Transmissions, and Automation in Design, September 1986, Vol. 108, pp. 315-322. [2] Khulief, Y. A., Shabana A. A., “Dynamic Analysis of Constrained System of Rigid and Flexible Bodies With Intermittent Motion”, Transactions of the ASME, Journal of Mechanisms, Transmissions, and Automation in Design, March 1986, Vol. 108, pp. 38-45. [3] Wittker E., “An Application of the Rigid Finite Element Method to Modeling of Flexible Structures”, Proceeding of Romansy 10, the tenth CISM-IFTOMM, Symposium on Theory and practice of robots and manipulators, Gdansk 12-15, 1994 pp. 72-78. [4] Hemanshu R. P., ‘‘Finite-Element/Lagrange Modelling and Control of A Flexible Robot Arm’’, 11th IFAC World Congress, Vol. 9 (1990), pp.239-243 [5] Parviz E. NIKRAVESH an Jorge A.C. Ambrosio, ‘‘ Systematic construction of equations of motion for rigid-flexible multibody systems containing open and closed kinematic loops’’, Int. J. for Numerical method in engineering, Vol. 32, 1749-1766 (1991). [6] M. S. Pereira and P. L. Proença, ‘‘Dynamic analysis of spatial flexible multibody systems using joint coordinates’’, Int. J. for Numerical method in engineering, Vol.32, 1799-1812 (1991). [7] Ghorbel F., Chetelat O., Lonchamp R., “A reduced model for constrained rigid bodies with application to closed-loop robots”, Proceedings of the 4th IFAC Symposium on robot control (SY. RO. CO. 94). Capri, Italy, septembre 19-21, 1994. [8] Haladou A., Maalej A., Ghorbel F., “Dynamic modeling of multibody constrained mechanisms part I: Rigid links robot”, accepted to be presented at the International Conference on Engineering Research & Development University of Benin, Benin City, Nigeria,15-17April 2008 [9] Yoshifumi MORITA, Hiroyuki UKAI, Hisashi KANDO, “Robust Trajectory Tracking Control of Elastic Robot Manipulators”, Transactions of the ASME, Journal of Dynamic Systems, Measurement, and Control, December 1997, Vol. 119, pp. 727-735. [10] Maalej A., “Application of DYNASIM Simulation to Engineering Problems”, Journal of Advances in Modeling and Analysis-B, Vol. 24, N4, pp. 1-12, 1992.

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ICERD 08020: Project-Based Education Using Distributed Teams: Experiences of a Tokyo-based and Stanford-based team C. Mbohwa Department of Quality and Operations Management, University of Johannesburg, Auckland Park Bunting Road Campus, P. O. Box 17011, Doorfontein 2028, Johannesburg, South Africa. E-mail address: [email protected] Tel.: 011-559 1202

ABSTRACT Recent trends in globalization of business operations and education has increased the need for global teams. These teams face a variety of challenges. This paper discusses the experience of distributed teams made up of participants from the Tokyo Metropolitan Institute of Technology and Stanford University in carrying out a design and development assignment. Challenges faced included differences in culture, in time and experience and the use of distributed information to develop a new product. Better product development demanded at least one face-to-face meeting, setting milestone deadlines and heavy use of electronic media, especially telephone and video conferencing. 1. INTRODUCTION This paper discusses experiences based on a project carried out by a distributed team to design an in-vehicle interface for the purpose of assisting the driver to overcome fatigue and sleepiness while driving alone. Within this main objective, this team created a number of activities as follows:  The design of an in-vehicle media capture system that can be used to relieve driver tedium, improve alertness and enable friendly interaction with the driver  The construction of a functional prototype of the in-vehicle media capture system and make sure that it really works  The testing of this system with the North American drivers to check its usability, suitability and popularity.  The design, construction and testing of a voice-activated interface system that can enable Internet surfing, communication between the driver and the system and voice communication in using the invehicle media capture system  Experimentation on the prediction of the condition/state of the driver using the voice that is captured when the driver is interacting with the voice-activated interface.  Making recommendations to the sponsoring company on the way forward. The Stanford University team, consisting of two United States citizens and one Canadian, concentrated on the first three activities and the Tokyo Metropolitan Institute of Technology (TMIT) team, consisting of two Japanese and one Zimbabwean, concentrated on the fourth, fifth and sixth activities. The team members provided input on all the activities through DocuShare (an electronic system that was used to share documents at Stanford University), Internet, e-mails and teleconferencing (both video and audio teleconferencing). There were teaching teams in both countries assisting the team members. The work involved a review of literature on the use of various technologies in coming up with a virtual passenger system, voice-activated interface and aspects on driver systems that exist already. The design for a voice-activated interface was then undertaken. An information browser system was constructed and tested. Experiments were done to try to use the voice profile in determining the state of the driver. Definite patterns were recognized for specific states. This data was stored in memory and used to give a rough condition of the driver. Finally some recommendations were given to the client company. Some concluding remarks on the way forward and suggestions the direction that work in future can take were made. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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This study was prompted by the successful application of teleconferencing in companies like NEC Japan. [1] The system uses the Internet, video-conferencing, telephone conferencing and real meetings. This model was used for the distributed team. The three participants from Stanford University visited Tokyo, Japan for three days and in return two members from the Japanese team were supposed to visit Stanford University. However because of VISA processing delays for the Zimbabwean member of the Japanese team only one member managed to visit.

2. ICT SYSTEMS USED BY THE DISTRIBUTED TEAM Videoconferencing is essentially communication across long distances with video and audio contact that may also include graphics and data exchange. Digital video transmission systems typically consist of a camera, codec (coder-decoder), network access equipment, network, and audio system. The benefits expected in using these information and communication technology (ICT) tools in substituting live meetings are, cost savings like removing the need to pay travel business allowances, avoiding loss of working time and reduced hotel costs. Some studies indicate that teleconferencing systems, that is videoconferencing and audio conferencing equipment, have a payback period of less than one month. [2] Tele- and videoconferences can replace conventional meetings and reduce travel. This is significantly so when travel by air is substituted. The traditional model for the link between overseas and local team members is as depicted in Figure 1 Team Members in Japan

Team Members in the USA

Travel by train or car then by air followed by train or car and hotel accommodation

Figure 1: Traditional CDIO distributed team link The system that was used for electronic communication using telephone conferencing and videoconferencing for distributed team communication is shown in figure 2. The equipment consists of servers and personal computers to enable Internet access and information exchange between the two locations. Two PCs and a server were needed at each of the two locations. Teleconferencing was scheduled bi-weekly. A couple of sessions were cancelled through e-mail communication when the need for one was not identified. Because of technical hitches videoconferencing was very rarely used. The system started working faultlessly after the project had been finalized, demonstrating that technical problems that reduce effective communication need to be addressed decisively at the beginning of such projects. Team members from both countries visited the client car company in Japan together and had fruitful face to face interaction during that time. The team spent 3 intensive days together planning the work and clarifying many communication problems. This was a very useful exercise, since it not only resolved some collaboration hitches, but enabled personal touch and communication among the team members. Observations, surveys, interviews, physical tests, questionnaires and condition detection experiments were later done in the USA. Microsoft Messenger services were also used whenever two or more members of the team were online to enable data and information update. Brainstorming sessions were conducted during teleconferences and members were brought to the same page through these e-meetings.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria Team in Japan: Server and computers

PictureTel System

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Team in the USA Server + 2 computers

PictureTel System

FIGURE 2: CONFIGURATION OF THE ICT SYSTEM

3. The information browser system The Japan team conceptualised the “Human Friendly Interactive Interface” as a passenger who helps in using the systems inside the car. Attention was paid to two points, that is, the need to concentrate the driver’s eyesight to road and the need to keep the driver’s hands on the driving wheels all the time. It was decided that the system’s interface should use voice recognition software, personal computers (PCs) and a simple menu structure. The system consisted of two PCs, LINUX software and ViaVoice 9 (voice/speech/text recognition software). One PC is located inside the car and the other was used as an external server. The reason for using an external server was to keep the system inside the car very simple. This way a simple and basic car computer could be used. In order to enable communication inside the car system and with the external server, HTML(Hyper Text Markup Language) was used. This was because HTML, can provide the menu easily and all equipment’s menu for the same structure can be accessed easily. The in-car system program performed the next tasks: Getting the users’ voice input; getting information from the external server system and; providing output information. This system was developed with Linux, IBM ViaVoice 9 SDK (System Developers’ kit), a microphone and a speaker. The system stays on standby and is prompted by a voice message, to which it responds appropriately. It was tested with the following commands: Click: Chooses the menu item (click the link) Back: Moves back to the previous menu item Forward: Moves forward to the next menu item The following commands were prepared to directly change the menu or category: Music; System selects the music in the menu and starts playing: News; System selects the news item in the menu and starts playing. A possibility was given to select news category such as a “Sports”, “Economics”, “Politics” and many more, all of which could be voice prompted. Some text to speech experiments were conducted. However the system read the text monotonously and with some difficulty. A link was connected to the external server to improve information sources. The external servers system was developed using Linux enabling it to communicate with the in-car system transferring information from the Internet. This system worked reasonably well in Japan. However, when the design was transferred for use in the USA, the software could not easily pick spoken commands and offered less functionality. Transfer of software, programs and system configuration did not help. Some of the software was sent by Federal Express to meet the project deadline. However the trouble shooting skills available in the Japan Team were not there on the other side. The Japanese software expert and trouble shooter got the USA too late and as a result, a hand operated display had to be used in designing a media capture and playback system. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

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4. Driver’s condition detecting system The “Driver’s condition detecting system” was designed as an attempt to detect a driver’s condition using the driver’s voice commands. Periodically the system prompts the driver into giving commands, which are captured by the “Information browse system” discussed in the previous section. The condition detecting system simultaneously records the voice data in ‘”wave form [*.wav]”. It compares the voice data with the classified data patterns in the voice data memory system and judges whether the driver’s condition is suitable for driving. In order to investigate the driver’s possible wave form for different conditions, experiments were carried out for various predetermined emotional conditions. The word that was used for voice recognition capture was “SPORTS.” The assumed mental conditions were ”composed”, ”happy”, ”angry”, “sad”, “irritated”, “depressed” and “tired” In order to improve voice-capture accuracy each person practiced 3 or 4 times until the voice was recognized. The recording of “composed voice data” was done after a signal was given. The subject simulated the various conditions. Sufficient time was given and more practice done to enable the subject to pronounce the word expressing different emotional sentiments. It was not easy to get the subjects to adjust to different mental conditions. However in the end different waveforms were noticed for different states. Here again the experiment was conducted in Japan and different waveforms would be expected for different people and for Americans. Figure 3 shows one of the subjects’ voice data.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

Composed

991

Angry

fell-1 1

Depressed

0.8

Happy

0.6

V ibration level

0.4

0.2

0

-0.2

-0.4

-0.6

-0.8

-1 0

1

2

3

Irritated

4 tim es

5

6

7

8 4

x 10

Sad

Tired

Figure 3: Voice Data for one Male Subject

The voice data was analyzed using MATLAB. This software was used to classify the data into normal speaking data and other data for simulated conditions using the former for comparison and analysis. In pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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addition, the maximum amplitude of the voice data [max_wave], the average of voice volume [Ave.] and the deviation of voice volume[Dev.], were investigated. Similar results were obtained from the eight subjects. Results from one of the subjects are classified as follows: ”composed” --- Loud and clear voice. (Basic data); “happy”---- Speaking a little bit faster. (Compared with Basic data); “angry”---- Speaking at the same volume. The average value of the size of voice signature was larger. (Compared with Basic data); “irritated”--- It was guessed that the intonation of the voice is lost; “depressed”, ”sad”, ”tired”--- The voice signature became small on the whole, in all three states. So, distinguishing the three mental conditions was found to be difficult. From these results, a driver’s condition detecting system using voice was proposed. On its basis, the media capture systems would be activated appropriately, to address the condition of the driver. A warning system was proposed, that can send information to another person who can then phone the driver and engage them with a view to convince them to take a rest. It was found to be very difficult to finely define the condition of the driver on the basis of voice alone. The driver’s mental condition can be detectable by also measuring the change of blood pressure and heartbeat. The next table expresses the changes of mental condition that are expected due to changes in blood pressure and heart beat. Table1: Relation between body information and Condition Increase Normal Decrease Worried Relaxed Blunt Blood and and judgment pressure Surprised Angry Stable Sleepy Heartbeat Strained and Tired It was concluded that a driver’s mental condition detecting system can be more accurate if it uses the correlation of the results of the body information system and the results of the voice information system. However the system developed in the end was a media capture and playback system that required minimal distraction since it had a limited menu. 5. LESSONS LEARNT The use of distributed teams in conceiving, designing, implementing and operating poses more challenges. Doing so using a local team is challenging enough hence these experiences will be found useful for engineers that want to take that route. Distributed teams have become a daily reality due to globalization. The lessons learnt are as follows:  The weekly meeting with teaching teams from both universities and countries changed the direction of the project many times. Two other parties, the teaching assistants and supervisors from both universities, came into play and this prolonged decision making and taking  The success of such a project requires good cultural understanding. Language was a barrier for one of the Japanese team members, reducing full participation. Team methods, skills and thought processes were different also. It took some time to reach a working relationship. This problem can be minimized by arranging for face to face meeting during the early stages of the project  Excessive data was created or compiled in electronic form. Initially most of the team members did not bother to read it. However when the person posting the data summarized it, the response rate improved. The effort of summarizing data is important, because it conveys critical information that would otherwise be ignored  When planning such projects, include the details. Time saving changes, which are done in the USA and not in Japan cost the group two scheduled meetings. Critical dates like those when there are changes to winter time or summer time need to be noted. Also the time and day differences posed further challenges. For example Thursday 8pm at the University of Stanford was Friday 12 noon at the Tokyo Metropolitan Institute of Technology in Japan. The final project finalization and presentation was compromised because the second team member could not travel as the VISA application to enter the USA took a long time to be processed. Also the team member that travelled pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

 





993

from Japan to the USA went there too late to make an impact on the final product. Better financing and planning could have avoided this problem. All communication technical hitches like those to do with videoconferencing and unreliable Internet should be resolved before the inception of the project It is important at the onset to select and agree on tools, equipment and specifications to be used, taking care to avoid choosing too many of them. At one time the teams were working in completely different directions because they could not agree on the way forward. There is a need for an authoritative body that enforces the final direction of the project The team members should work on a tight deadline and there must be a time beyond which new ideas and design changes are no longer accepted. In this case new ideas kept on coming until the last stages of the new product development. This negatively affected the quality of the final product Methods should be put in place to enable effective transfer of designs, programmes and data/information needed for the final product development.

6. THOUGHTS FOR THE FUTURE In conclusion, it is clear that distributed teams will become a more frequent feature in future as more systems become global in nature. The question is no longer whether or not to have such systems, but how to make such teams more effective in managing distributed-team projects. The following are recommended: o o

There is need for more work and research on how to make distributed teams more effective Information and Communication Technology will play a very significant role in future, hence there is a need for organizations to constantly update and upgrade their systems so that they can facilitate more effective information exchange among the project partners local or distributed. They also reduce the number of expensive live meetings, which involve a lot of travel and environmental pollution

References [1] NEC, 2001, Annual Environmental Report April 200 – March 2001, A Look into the Next Chapter of Ecology and Technology [2] Arnfalk Peter, 2000, The Use of Telework and Teleconferencing in Travel Reduction, Paper for the EcoEfficiency 2000 Conference, June 2000, Malmo

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(ICERD 08039) Fractal Analysis of Area-Perimeter Relationship of Some Selected Countries of the World A.E. Adeleke1 and T.A.O. Salau2 1 Mechanical Engineering Department University of Agriculture P.M.B 2240, Abeokuta, Nigeria e-mail: [email protected] 2Mechanical Engineering Department University of Ibadan, Ibadan. e-mail: [email protected]

ABSTRACT Boundaries of six selected countries one from each continent were studied, using fractal dimension technique. The Area – Perimeter relation method was used, where land area covered and boundary length of designated countries were measured in the unit of known box size (Box counting). The log-log plots of these variables were obtained and the slopes were measured as the required dimensions. Fractal dimensions determined lie between 1.19 and 1.55. The scale size of the maps, and the number of states both had no significant effect (p>0.05) on the fractal dimensions obtained.

INTRODUCTION Many patterns of nature are often irregular to such an extreme degree that Euclidean (or classical) geometry cannot describe their form [5]. Klonowski [4] reported that, during the last decade it has widely been recognized by physicists working in diverse areas that many of the structures common in their experiment possess a rather special kind of geometrical complexity. This awareness is largely due to the attention to the particular geometrical properties of such objects as the shores of continents, the branches of trees, or the surface of clouds. Thomas et al. [15] contributed that any shape can be characterized by whether or not it has a characteristic length. Characteristic length is a convenient reference length (usually constant) of a given configuration, such as overall length of an aircraft, the maximum diameter or radius of a body of revolution, or a chord or span of a lifting surface. Characteristic length can define any regular shape geometry, such as a sphere, cube e.t.c., and the shapes with characteristic length have an important common peculiarity of smooth surface. Shapes having no characteristic length are self-similar or scale- invariant since these shapes do not change their shape under a change of observation scale.

Most branches of science and engineering are now using fractal analysis for characterizing natural or synthetic particles, and complex physical or chemical processes. Fractal dimensions have been successfully used to describe the ruggedness and geometric complexities of both natural and synthetic particles [2, 11, 9, 16]. In addition to its application to problems in engineering and physical sciences, the fractal dimension has a rapidly increasing variety of uses in contexts ranging from urban and landscape planning [6] to oceanography and Meteorology [3,7].

The fractal dimension can be estimated by structured walk (Richardson’s plot), dividers (compass) method, grid (Box counting) method, probability-density function, size-frequency distributions, branch order relationships, spatial and temporal series and two-surface method. The objective of this study was to determine the fractal dimension of the boundary of countries selected from each of the continents in terms of their perimeter-area covered on the map and associate physical meaning and interpretation using grid method.

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MATERIALS AND METHOD

Materials and Material Preparation Materials used for this study include the following; (i) Scale map of Nigeria (http://www.Lib.u texaz- education /maps/Africa/Nigeria –Pol96 jpg.) (ii) Scale map of Australia (http: //www. World time zone .com/time – Australia.htm) (iii) Scale map of Mexico (http: //www .maps – of – Mexico .com/) (iv) Scale map of Argentina (http: //www. liibutexas.edu/maps/America/argentine –Pol96 .jpg.) (v) Scale map of Germany (http://www .Ulib.Iupui.education /kad/name word/map4 html) (vi) Scale map of China (http: //www > Fotw. Net/flags/Mxhtm# map) (vii) Grid of 1mm by 1mm size was prepared to cover size A4 paper using Microsoft Word Processor followed by photocopying the hard copy of same onto transparent sheet at room temperature.

Model and Method The Area-Perimeter relationship method given by Eqn.(1) was used for this study. This method measures the extent at which the states/provinces boundaries “fill’ the two dimensional plane. P = KAD/2 (1) Where the area (A) is the number of 1mm by 1mm square boxes making up a given state land area, the perimeter (P) is the count of the number of 1mm by 1mm square that falls on the edges of the state boundary. D is the fractal dimension and K is the proportionality constant.

A fragmented scale map of the country to be analyzed was placed on the drawing board and the transparent grid of size 1mm by 1mm was arbitrarily and firmly placed on it. The numbers of boxes (squares) that fell on each of the state of the country were then counted as estimate of its area. Likewise the numbers of the squares that fell on the edge of the boundary were counted as an estimate of the perimeter. The number of state or province as each case may be, determined the number of solution points on a log P versus logA½ plane as given by Eqn. (2) Log P = D logA½ + log K (2)

Eqn. (2) was obtained by taking log of both sides of Eqn. (1).The slope of the resulting graph of Eqn. (2) gives a measure of D. The above procedures were carried out at two different levels of map enlargement, and replicated for each of the selected maps. The mean data were then used for the analysis. ANALYSIS (a) Values of P and A for all states in each country were plotted on log-log graph using Eqn (2). The slope of the graph of Eqn.2 was taken as the fractal dimension D. (b) The D values obtained for each set of experimental run were subjected to a t-Test to determine the difference in means for the two cases considered [8].

RESULTS AND DISCUSSION Figure 1 and Figure 2 show the map of Nigeria drawn to scales1.1cm:100km and 1.32 cm: 100km respectively. The Perimeter/Area obtained for the two scaled maps of Nigeria (Figure 1 and Figure 2) including F.C.T is as shown in Table 1.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 1. Map of Nigeria drawn to Scale 1.1cm: 100km

Figure 2. Map of Nigeria drawn to Scale 1.32cm: 100km Note that the numbering of the states in both Figure 1 and Figure 2 is arbitrary.

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

Table 1. State s

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37

Perimeter/Area of Nigerian States including FCT (In terms of Box Counting)

Scale:1.1cm:100k m Perimet er Area 63 98 39 61 44 98 41 60 32 56 43 60 49 106 58 158 76 165 48 101 56 97 33 68 49 86 59 138 46 92 25 42 53 92 37 72 19 27 16 21 46 72 41 76 36 56 14 14 18 25 17 19 33 51 31 40 34 46 12 11 28 47 15 18 25 34 15 16 22 22 18 21 15 21

Scale:1.32cm:100k m Peri meter Area 75 131 47 85 55 138 48 83 38 73 50 88 60 145 68 182 81 193 51 142 60 130 36 92 60 117 72 185 54 125 28 57 63 122 47 92 24 37 18 27 53 98 49 104 44 74 18 22 20 31 20 24 38 68 36 54 47 63 15 14 38 68 18 24 27 42 15 19 26 85 18 26 20 30

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria

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The values obtained for the Perimeter/Area measured for scale 1.1cm: 100km was always less than that of scale 1.32cm: 100km as expected. These values were plotted on a log-log scale as shown in Fig.3 and Fig.4 to determine the fractal dimension D from the slope of the line of best fit. The coefficient of determination (R2) was always greater than 0.90 in all cases considered as shown in Table 2, showing a good correlation between experimental and predicted values. Fig.3 Graph of LOG (PERIMETER)/LOG (AREA) of Nigerian states including F.C.T. (scale 1.1cm: 100km) y = 1.3513x + 0.3557 R2 = 0.9541

2

LOG(PERIMETER)

1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0

0.5

1

1.5

0.5LOG(AREA)

Fig. 4 Graph of LOG (PERIMETER)/LOG (AREA) of Nigerian states including F.C.T (Scale: 1.32cm:100km).

LOG(PERIMETER)

2.5 y = 1.3532x + 0.3321 R2 = 0.9221

2 1.5 1 0.5 0 0

0.5

1

1.5

0.5LOG(AREA)

Table 2. Fractal Dimensions of the Countries Analyzed.

Countries No. of states as of 2005 China

31

Fractal Dimension (D) Scale Scale 1 2 1.29 1.29

(R2)

Scale Scale 1 2 0.92 0.94

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2nd International Conference On Engineering Research & Development: Innovations (15th – 17th April 2008), Benin City, Nigeria Argentin a Nigeria German y Australi a Mexico

1.8

999

23

1.23

1.22

0.90

0.90

37 16

1.36 1.42

1.35 1.37

0.95 0.99

0.92 0.99

7

1.19

1.21

0.98

0.98

32

1.54

1.55

0.96

0.96

Estimated Fractal Dimension

1.6 1.4 1.2 1.0 0.8

y = 0.0056x + 1.203 R2 = 0.2343

0.6 0.4 0.2 0.0 0

10

20

30

40

Num ber of States in Country

Figure 5. Graph of Number of States versus Estimated Fractal dimension at Scale 1. Figure 5 depicts the relationship between the number of state and the estimated fractal dimension D. There was a poor correlation between two variables where the coefficient of determination (R2) was below 0.5. This implies that the fractal dimension D is independent of number of states. The fractal dimension of the boundary of the countries studied lie between 1.19 and 1.55 as shown in Table 2 which is in consonance with previous researches[12,1,11], that D values must be between 1.0 and 2.0 for fractal images in 2- dimensional plane. For all the countries considered the fractal dimension of each experimental level appears the same confirming that the fractal images have a range of self similarity over any scale range as reported by some researchers [12, 15]. Comparing the fractal dimensions of Australia and Argentina( Figures 6 and 7 respectively), it becomes relatively easier to see that two fractal objects may appear visually different and yet have the same fractal dimension in agreement with Smith et al. [13]. Australia has the lowest fractal dimension which may be due to its less fragmented states compare to the other countries studied which had more compacted states. It has been reported by Ogata et al. [10] that degree of fragmentation has an effect on the fractal dimension of fractal images. Higher values indicate higher roughness of the boundary.

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2nd International Conference On Engineering Research & Development: 1000 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 7. Map of Argentina drawn to scale 0.95cm: 100km

A t-Test performed on fractal dimension for the countries considered shows that at 95% confidence level there were no significant differences between the two scales of maps considered for the research. CONCLUSION The D values for the countries analysed lies between 1.19 and 1.55. There was no influence of number of state on fractal dimension. The scale of drawing used was not a significant factor in fractal dimension D obtained for all cases considered. There was a good correlation between the experimental and predicted values with the coefficient of determination (R2) varying from 0.90 to 0.99. A t- Test performed also showed that there was no significant variation between the two levels of map scales used in the research. This study has re-established the characterizing potentiality of fractal dimension in one part and suggested the likelihood of political instability in countries with higher fractal dimension resulting especially from the rough states boundary .Further research work is required in this direction. REFERENCES 1. B. Alabi, “From Vibrations to Fractals” Excitement at the Frontiers of Knowledge. An Inaugural Lecture Presented. University of Ibadan. (2001). 2. J.C. Graf, The importance of resolution limits to the interpretation of Fractal descriptions of fine particles. Powder Technol., (1991) 67, 83-85. 3. P.S. Jain,”Fractal dimensions of clouds around Madras” Mausam, 40 (1986) 311-316. 4. W. Klonowski,.”Signal and Image Analysis Using Chaos Theory and Fractal Geometry” http://www.fractal.org/Life-ScienceTechnology/publications/ Fractal signals. 2000. 5. B.B. Mandelbrot, ”Fractals Form, Chance, and Dimensions” W.H. Freeman, San Francisco. 1977. 6. B.T. Milne, “The utility of fractal geometry in landscape design” Lands. Urb. planng, 21 (1991)81-90. 7. A.I. Morrison, and M.A. Srokosz “Estimating the fractal dimension of the sea surface: a first attempt” Ann. Geophysics, 11 (1993)648-658. 8. B.H. Munro,”Statistical methods for health care research”,Leppincott, fourth edition.2001. 9. T. Nagai, and Y. Yano, ”Fractal structure of deformed potato starch and its sorption characteristics” Journal of food science, 55 (1990)1334-1337. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1001 Innovations (15th – 17th April 2008), Benin City, Nigeria 10. Y. Ogata, and K. Katsura, “Maximum likelihood estimates of the fractal dimension for random spatial patterns” Biometrika, 78 (3) (1991) 463-474. 11.M. Peleg, and M.D. Normand, “Characterization of the ruggedness of instant Coffee particle shape by natural fractals” Journal of food science, 50(1985) 829-831 12. Jr., T.G. Smith, W.B Marks, G.D. Lange, Jr.,W.H.Sheriff, and E.A. Neale, “A fractal analysis of cell images” Journal of Neuroscience. 27 (1989)173-180. 13.Jr.T.G.Smith, G.D.Lange and W.B.Marks ”Fractal methods and result in cellular morphologydimensions, lacunarity and multifractals” Journal of Neuroscience, 69, (1996)123-136. 14. H. Takayasu, Fractals in the physical sciences. Manchester University press, Manchester. (1990). 15. T.R.Thomas, and A.P. Thomas, “Fractals and engineering surface roughness” Surface Topography, 1,(1988) 143-152. 16. T. Yano, and T. Nagai, “Fractal structure of starchy materials transformed with hydrophilic alcohols” Journal of Food Engineering, 10, (1989)123-133.

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2nd International Conference On Engineering Research & Development: 1002 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08071) SOLVING TIME MANAGEMENT PROBLEM IN TRANSPORTATION - AN OPTIMIZATION ALGORITHM APPROACH A. A Adeala, A. T Layeni Mechanical Engineering Department, Olabisi Onabanjo University, Ago-Iwoye, Ibogun Campus Transportation, either by air, rail, ship or motor vehicles, plays an important role in our modern life. Thus, efficient running of various transportation networks is significant for the present-day economy. Due to rural-urban migration there has been a large increase in urban population and an increase in car ownership which has consequently led to traffic jams on our roads.Considering a medium populated semiurban area like a university or college, it has been found that students still come late to school because of transportation problems. This is not as a result of traffic congestion or a bottle-neck along the road network but poor time management by the shuttling buses and improper location of bus stops for passenger pick up. This research work attempts to solve these problems by using an optimization algorithm taking into consideration the number of bus stops along the route of the bus, the capacity of the shuttling bus, the likely number of passengers available for pick up in each bus stops, and of course the maximum allowable speed for the shuttling bus and the distance from the drop off point and the farthest bus stop.

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2nd International Conference On Engineering Research & Development: 1003 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD08073) Municipal Waste Transport Network Analysis

A. T Layeni, M.A Sulaimon, A.O. Adesina, A. A Adeala, Mechanical Engineering Department, Olabisi Onabanjo University, Ago-Iwoye, Ibogun Campus

The municipal waste collection network in Nigeria as we have it now is plagued by many ineffective processes thus making the system ineffective. This is evident by the presence of waste littering the metropolis. The Lagos metropolis, for example, had a city plan that included a waste disposal system adequate for the size and the activities of the metropolis at the time the plan was formulated. That system is grossly inadequate for the explosion in the population and economic activities experienced in the metropolis in the last two decades. This has led to the ineffectiveness of the waste disposal system in the metropolis. The state government at various times have put on ground several systems in curbing this situation with little or no avail. The introduction of the monthly environmental sanitation programme has aggravated the situation than alleviate it due to inadequate collection system, the network available is plagued by problems of capacity and can be said to have failed the basic requirements; this is so because the root of the cause of the problem was not really considered in-depth before the programme was launched. The environmental sanitation programme from a technical perspective is a waste generating process, which implies that without a good collection and disposal system, waste generated will be left unattended to. This is evident by the waste littering all around the metropolis. This paper is a study of the application of the principles of the municipal water distributions network to the waste collection process to determine the appropriate volumetric flow vis-à-vis the adequate transportation system that will handle the flow generated

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2nd International Conference On Engineering Research & Development: 1004 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08076) A BI-OBJECTIVE OPTIMAL WASTE COLLECTION SCHEDULING WITH WASTE VOLUME AND BIODEGRADABILITY CONSIDERATIONS.

‘Ladi Ogunwolu* ([email protected]), O. A. Alli and O. P. Popoola Department of Systems Engineering, Faculty of Engineering, University of Lagos, Nigeria. * corresponding author Introduction In this paper, a bi-objective urban solid-waste Collection Scheduling model with consideration for varying bio-degradability of waste components and projected generated volume is presented. Consideration of biodegradability of components of solid waste is of utmost importance in order to ensure environmental health in urban centers. This is very much imperative in a situation of limited financial resources for waste management resulting in shortfall in needed machineries to cater for the collection system. While the projected generated volume of urban solid waste is also of primary concern, for utmost health of the citizens and the collection staff, the degradable condition of solid-waste components need also to be taken into consideration. As exact volume and degradable conditions of the components of solid waste in an urban setting may be elusive, the method of fuzzy linguistic estimate, which are obtained from domain ‘experts’ in theory and practice for different urban land use characteristics typical in urban waste collection scheme are employed. These linguistic descriptions are aggregated and the defuzzified values are used as input into a Mathematical Programming scheduling model built to minimize the overall excess or deficit volume of collection and the bio-degradable status across the network of waste-collection schedule. Work Done The work presupposes pre-designed waste collection routes in the urban centre, leaving the collection time and by implication, the frequency within a given horizon of time to the scheduling exercise in the current exercise. For the purpose of qualitative description of expected nature and rate of bio-degradation of generated waste, the urban centre are divided into zones based on land use characteristics for which an expert rating of nature of predominant expected waste types can be made. The ratings are made with fuzzy linguistic descriptions for whose boundaries of distribution precise values are fixed. Similarly, the expected waste volumes are described by fuzzy linguistic variables. An Integer Linear Programme was developed for the problem. The constraints are waste collection vehicle capacities, available waste collection crew and the time-horizon the schedule is being generated for. The results using each of the individual objectives and this bi-objective approach are compared and analyzed to draw the conclusion on the advantages of the bi-objective approach taking care of projected generated volume and bio-degradable conditions of solid wastes in the urban center. Result The result vindicates the bi-objective approach as a better approach than using solely the generated volume or the bio-degradable condition of the waste components.

Discussion The result is a good compromise between volume-oriented approach of scheduling waste collection, which can only cater for environmental health where there are adequate availability of collection machineries and environmental health oriented approach. Even where and when all available machineries are available, the approach will find useful application in developing nations where the waste collection processes are fraught with managerial incompetence.

Selected References pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1005 Innovations (15th – 17th April 2008), Benin City, Nigeria 1. Tchobanogious, G., Theisen, H., and Vigil, A. S. (1993); Integrated Solid Waste Management. McGraw-Hill, Inc. International Edition. 2. Quon, J. E., Charnes, A., and Wenson, S. J. (1965). Simulation and Analysis of a Refuse Collection System; Proceedings ASCE, Journal of the Sanitary Engineering Division, Vol. 91, No. SA5, 1965. 3. Truitt, M. M., Liebman, J. C. and Kruse, C. W.(1970); Mathematical Modeling of Solid Waste Collection Policies; Vols. 1 and 2, Public Health Service Publication 2030, U. S. Department Health Education and Welfare, Washington, DC. 4. Ogunwolu, ‘Ladi and Popoola, O. P. (2006); Optimal Strategy for Waste Collection Planning in a Developing Economy under Fuzzy-Stochastic Uncertainties. An unpublished research work. Department of Systems Engineering, University of Lagos, Nigeria.

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2nd International Conference On Engineering Research & Development: 1006 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08077) Maintenance Productivity Measurement: Case Study of a Manufacturing Company O.A Alli(1), ‘Ladi Ogunwolu* (2) and Olukayode Oke(3) Department of Systems Engineering, University of Lagos, Akoka, Nigeria [email protected] , [email protected] , [email protected] *Corresponding author (1, 2, 3)

Abstract: This research involves measuring maintenance productivity and seeks to measure how maintenance of equipment affects the overall productivity of the company. The Stewart Utility Concept was used along with a scaling factor. Performance measures were identified and their values were obtained. Five productivity ratios were employed to obtain the overall maintenance productivity. Results from the graphs showed that Equipment Availability was 78.32%; Emergency Failure Intensity Ratio was 28.4%; Maintenance Cost Component was 32.39/btl; Cost of Maintenance hour was N125, 081/hr; Routine Service Worked was 92.03% and Cost of Reduction was 5.32hr/N. The overall maintenance productivity of the period under review was fairly good though there is room for improvement Average overall maintenance productivity was found to be 63.2%. This is an indication that there were evaluations and review of maintenance productivity within the period.

1.

Introduction

Productivity Measurement (PM) is a useful tool to analyze both labour and capital performance and determine the causes of changes over time. It reveals the areas that need improvement and control, aids effective management and optimal utilization of scarce resources thus avoiding wastage. Davies (1955) measured total productivity at the firm level. Barzel (1992) investigated and found output per unit input as a way of measuring productivity in electric power industries based on total factor inputs. Studies carried out by Brechling and Surrey (1966) on a coal fired electricity industry focused on the productivity of fuel and capital while Chandraseker (1981) based his studies on productivity in selected manufacturing industries in the United States and France on labour input. A follow-up of Davies’ work at measuring total productivity at the micro level was the work of Carl Thor of the American Productivity Center (APC), based on the work initially carried out at the National Productivity Institute of the Republic of South Africa. The APC model relates productivity to profitability and price recovery factor. Other productivity models are the Oklahoma Productivity Center model, which uses Multi-Factor, Productivity Measurement Model: a computerized approach to measuring productivity as relationship between quantities of output from a given organization, and quantities of inputs used to create those outputs (Swaim and Sink, 1983). At the national level in Nigeria, productivity awareness came into being in the 1970s. Lawal (1991) and Aduroja (1992) used a multi-attribute model to develop an aggregate utility curve for the productivity measure. Oladipo (1998) measured productivity of manufacturing firms and showed that many Nigerian firms are yet to em brace and apply the productivity ratios in controlling their production functions and process. Adelakun (1995) compared Gold’s Model, Company Performance Appraisal, and the American Productivity Center, APC Model. He identified the APC model as being unique with a broad outlook. Adedigba (1994) used Stewarts Utility concept to find the overall maintenance performance of Dunlop Nigeria Ltd. from 1987 to 1991.

2.

Methodology

Stewarts Utility Model, designed for measuring manufacturing productivity, was employed in determining the productivity of the maintenance department of Guiness Nigeria Plc (the company of our case study). This is because it gives one composite productivity measure, enhances a flexible method of arriving at the overall productivity target and involves the participation of key personnel, thereby capturing group wisdom and generating a commitment to the solution problem. In order to achieve the objective of this research, the following steps were taken: (1) Preparation/administering of questionnaires; (2) Data collection for a 5-year pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1007 Innovations (15th – 17th April 2008), Benin City, Nigeria period (2002-2006); (3) Identification of performance measures from the information produced; (4) Plotting of Graphs and utility curves of the performance measures. The utility curves were used to determine the corresponding utility values for each of the measures; (5) The utility values were multiplied by a Scaling Factor to obtain the Overall Maintenance Productivity of the company. The essence of Stewart’s approach is to combine various surrogate measures to produce a single number. 2.1 Data Classification and Analysis Data on production and maintenance activities obtained from 2002-2006 are: (1) Production Output; (2) Operating Time; (3) Downtime); (4) Total Maintenance Cost; (5) Planned Maintenance Hours; (6) Total Maintenance Hours. The following performance measures were identified on the basis of available data: equipment availability, routine service worked, cost of maintenance hour, maintenance cost component, and cost of reduction. Utility values, scaling factors and overall maintenance productivity/overall maintenance target were determined and were used to obtain performance measures, plot their corresponding graphs and utility curves. 2.2 Computation of Performance Measures The performance measures that were computed on the basis of available data obtained from the manufacturing company are (1) Equipment Availability (EA); (2) Emergency Failure Intensity Ratio (EFIR); (3) Cost of Maintenance Hour (CMH); (4) Routine Service Worked (RSW); (5) Maintenance Cost Component (MCC); (6) Cost of Reduction (COR). Below are the models used for computing each of the performance measures employed for each year

downtime  100% downtime  uptime downtime (2) EFIR   100% uptime Total Ma int enance Cost (3) CMH  Total Ma int enance Hour (1). EA 

Total Ma int enance Cost Pr oduction Output Planned Ma int enance Hour (5) RSW  Total Ma int enance Hour RoutineServiceworked [6] CR  Cost of Ma int enance Hour [4] MCC 

2.3 Determination of Utility Values The utility values for each of the performance measures were derived by: (1) Determining the best and worst values from the graph of each of the measures used; (2) Assigning values of 1.00 and 0.00 for the best and the worst measure respectively;(3) Taking five points between the best and the worst performance measure,(intermediate points) and assign values between 0.00 and 1.00;(4) Using the intermediate points with the best and worst measures for each measure to plot a Utility Curve in order to determine the Utility values. 2.4 Determination of Scaling Factors In determining the scaling factor, weights were assigned to the different performance measures. The weight of 100 points was assigned to equipment availability due to the ranking pattern. Weights were assigned to other performance in the same ranking manner. The weights of the performance were summed up and the ratio of a performance to total sum of performance was calculated to give the scaling factor of the various performance measures. Table 2 shows the scaling factors. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1008 Innovations (15th – 17th April 2008), Benin City, Nigeria Table 1:

Table for obtaining Utility Values for the intermediate values for each Productivity Measure INTERMEDIATE PERFORMANCE MEASURE UTILITY VALUE VALUE 68.0 0.08 72.0 0.33 Equipment Availability 77.0 0.58 82.0 0.87 N 252150.7 0.10 N 152150.7 0.40 Cost of Maintenance Hour N 102150.7 0.74 N 72150.7 0.94 N 55/no of crates 0.14 N 47/ no of crates 0.28 Maintenance Cost Component N 33/ no of crates 0.58 N 20/ no of crates 0.87 INTERMEDIATE PERFORMANCE MEASURE UTILITY VALUE VALUE 50% 0.18 Routine Service Worked 70% 0.45 80% 0.63 90% 0.86 13.00 hour/ N 0.09 10.47 hour/ N 0.34 Cost of Reduction 7.47 hour/ N 0.63 4.72 hour/ N 0.92 40.60% 0.12 30.57% 0.46 Emergency Failure Intensity Ratio 25.57% 0.73 20.00% 0.94

Table 2:

Scaling Factor Performance Measure

Weight

Scaling factor(K)

A

Equipment Availability

100

0.191

B

Cost of Maintenance Hour

95

0.181

C

Maintenance Cost Component

90

0.171

D

Routine Service Worked

85

0.162

E

Cost of Reduction

80

0.152

F

Emergency Failure Intensity Ratio

75

0.143

Total

525

1.000

Table 3: Overall Maintenance Target Value PERFORMANCE MEASURES TARGET VALUE EQUIPMENT AVAILABILITY COST OF MAINTENANCE HOUR

78.32% N125,081.90/H

UTILIT Y VALUE 0.66 0.58

SCALIN G FACTOR 0.19 0.181

TARGE T 0.125 0.105

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2nd International Conference On Engineering Research & Development: 1009 Innovations (15th – 17th April 2008), Benin City, Nigeria MAINTENANCE COST COMPONENT ROUTINE SERVICE WORKED COST OF REDUCTION EMERGENCY RATIO TOTAL

3.

FAILURE

r N32.39/btl 92.03% 5.32Hr/ N

INTENSITY 28.4%

0.28 0.89 0.85

0.171 0.162 0.152

0.048 0.144 0.129

0.56

0.143

0.08 0.632

Results And Discussion

The results are as shown in the figures.

Figure 1. Graph of Equipment Availability

Figure 2. Graph of Emergency Failure Intensity Ratio

Figure3. Graph of Maintenance Cost Component

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2nd International Conference On Engineering Research & Development: 1010 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 4. Graph of Cost of Maintenance Hour

Figure 5. Graph of Routine Service worked

Figure 6. Graph of Cost of Reduction

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2nd International Conference On Engineering Research & Development: 1011 Innovations (15th – 17th April 2008), Benin City, Nigeria Figure7.Graph of Total Maintenance hour 3.1 Equipment Availability (EA): The highest point of the Equipment Availability (EA) is in September 2002 where the equipment availability is 86.5% and the lowest is December 2004 where equipment availability is 67.5%. The target, which is the best average equipment availability ratio, is 78.325% in the year 2003. This best average, when compared with other months, shows that equipment availability performed below the target in the following months: February, March, May, July and Nov 2002; April, May, October, November and December 2003; January, May, July, Aug, Oct, November and December 2004; January, March, July, August and September 2005; January, February, March, June, October, November and December 2006. 3.2 The Emergency Failure Intensity Ratio (EFIR): EFIR is relatively in an upward trend from July to November 2003 before a slight drop in December It could also be observed that there is a downward trend from September to October 2005 before a relatively constant value in the same year. The worst and the best values of EFIR of other months showed that many months performed below the best average. The reason for this poor performance in some months was the frequent breakdown of the machines at these periods. 3.3 Maintenance Cost Component (MCC): This is the cost of production per good. The target/best average observed ratio was N32.39 per bottle, which was taken as the base period value for the measure for the period of study. From the graph of MCC, it can be observed that the performance ratio was poor for the following months when compared to the base period value. Some months’ MCC are below the target value because of the high cost of spares used to restore the equipment to good operating condition. 3.4 Cost of Maintenance Hour (CMH): In April 2005, the highest cost of maintenance is because the cost of maintenance spares and consumables are high and not necessarily because of breakdown. A critical look at the graph of EA shows that April 2005 actually has one of the highest EA value. The cost of maintenance hour seemed to experience a downward trend from April to July 2005 and July 2003 to November 2003 and hit its lowest in December 2004 after fluctuating earlier in the year. The best average observed maintenance productivity ratio was N 125,081.9/hr in 2004 for the period of study, which was taken as the base period value for the performance measure. 3.5 Routine Service Worked (RSW): It was observed that the graph of RSW in Fig. 3.6 that the worst downward trend were in the month of October to December 2004, with December being the lowest value for the performance ratio. This was as a result of frequent breakdown of the machine at the time owing to poor execution of preventive maintenance. 2005 and 2006 showed relative constant up trends from January to August and March to September respectively. The RSW seemed to stop at 100%, meaning most of the time maintenance goes as scheduled by the maintenance department. The performance ratios were low when compared to our best average performance value of 92.025% in some months. 3.6 Cost of Reduction (COR): The year 2005 shows a relatively good performance of COR. The best and the worst COR were in the year 2005 with the values 1.47 and 9.72 respectively. The best average observed COR ratio 5.3208 in 2005.

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2nd International Conference On Engineering Research & Development: 1012 Innovations (15th – 17th April 2008), Benin City, Nigeria 3.7 Overall Maintenance Productivity: From Table 1, the overall maintenance target was found to be 63.2%, which when compared with the values of Overall Maintenance Productivity of every month from 2002 to 2006 some months were found to be less than the Overall Maintenance target.

4.

Conclusions

The overall maintenance productivity of the period under review was fairly good. Although performance was below average in some of the months, it could still be said that the result was fair. It should also be noticed that though there were quite a number of months below average, some months showed considerable rise in trends. This is an indication that there were evaluations and review of maintenance productivity but there is still a lot of room for improvement. If the average of the Overall Maintenance Productivity of each of the years were found, it would be observed that the maintenance department performed badly. This is because only one of the years performed slightly above the target and that was year 2003 with an average annual Overall Maintenance Productivity of 63.3% as compared to the target which is 63.2%. This indicates that yearly appraisal of the activities of the maintenance department is either poor or nonexistent

5. [1] [2] [3] [4] [5] [6]

[7] [8] [9] [10] [11]

References Sink, D. S. (1983), “Much Ado about Productivity: Where Do We Go From Here” Industrial Engineering Journal, Vol. 42, No. 3, pp. 36 - 48. Kendrick, J.W. and Creamer, O. (1965) “Measuring company productivity” Handbook in the case studies in economics No. 189, National Industrial Conference Board New York, pp 53- 68 Craig, C.R. and Harris C.R. (1973) “Total Productivity Measurement at the Firm Level” Sloan Management Review. Vol. 14, No.3 Oladipo, E.O. (1988) “Productivity Measurement and Investigation: The case with a Manufacturing Firm”. Unpublished B.Sc Industrial Engineering Project, University of Ibadan, pp 6-18 Sumanth, W.T. (1984) “A Review of the Approach to the Measurement of Total Productivity in a Company/Organisation”. Proceedings of the Fall 1984 Industrial Conference. Swaim, J and Sink, D.S. (1983) “Productivity Measurement in the Service Sector: A Hotel/Motel Application of the Multi-Factor Productivity Measurement Model”. International Industrial Engineering Conference Proceeding Industrial Engineering Issues in White Collar Productivity, pp. 161-173. Barzel, Yoram, Levis A.K. (1992) “Ronald Coase on the Nature of Social Cost as a Key to the Problem of the Firm” the Scandinavian Journal of Economics, Vol. 94, No.1 pp 19-31 Brechling, F.P.R. and Surrey, A. J. (1966) “An International Comparism of Production Techniques: The Coal- Fired Electricity Generating Industry” National Institute of Economics Review, pp 30-42 Chandraseker, Krishnamuti (1981) “Productivity and Social Indicators.” The Annals of the American Academy of Political and Social Science, Vol. 453, No 1, pp153-168 Lawal, K. O. (1991) “Maintenance Performance Measures In Production Organization” Unpublished M.sc Industrial Engineering Project, University of Ibadan, pp 10-13 Aduroja, B.O. (1992) “Maintenance Productivity Analysis in a Wire and Cable Company” Unpublished B.sc Industrial Engineering Project, University of Ibadan, pp 5-18

[12]

Adedigba T.O (1994) ”Maintenance Productivity Measurement of a Manufacturi-ng Firm”, unpublished B.Sc project, Department of Industrial Engineering, University of Ibadan.

[13] [14]

Davies H. (1955) “Productivity Accounting”. Mc Graw Hill Book Company Akinlo, E. A. (1996), “Improving the Performance of the Nigerian Manufacturing Sub-Sector after Adjustment.” The Nigerian Journal of Economic and Social Studies, Page 9-10

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2nd International Conference On Engineering Research & Development: 1013 Innovations (15th – 17th April 2008), Benin City, Nigeria

ICERD 08080: OPTIMAL LABOUR ALLOCATION IN A CHALLENGING ENVIRONMENT: DYNAMIC PROGRAMMING MODEL.

S.D. Okonta & A.K Odior Dept. of Statistics, Delta State Polytechnic, Otefe-Oghara. +234 805 286 7898, [email protected]

Abstract This paper discussed the theory of multistage decision making problem in an industrial sector. It used the principle of optimal dynamic programming to achieve the best decision an engineer will take when confronted with challenging alternatives. The graphical display of the solution to the dynamic problem of the three companies under consideration give a maximum satisfaction to the initial confused engineer. Introduction In this paper we address a basic production line problem where an engineer is faced with challenging competitive jobs, as well as a fixed time and limited resources. The objective is to maximize the throughput (production rate) of the production line [1]. A lot of question is asked: whether a perfectly balanced allocation of labour and work quantity would be optimal? Or, would a balanced labour allocation with appropriate unbalanced work quantity allocation be optimal? In general, what is the optimal labour and work allocation? Many decision-making problems involve a process that takes place in such a way that at each stage, the process is dependent on the strategy chosen. Such type of problems is called Dynamic programming problems [2]. It is concerned with the theory of multistage decision process [2,3]. Mathematically, a dynamic programming problem is a decision making problem in n variables, the problem being sub-divided into n sub-problems, each sub-problem being a decision making problem in one variable only. The solution to a dynamic programming problem is achieved sequentially, starting from one (initial) stage to the next, till the final stage is reached [3,4]. The computations at the different stages are linked through recursive computations in a manner that yields a feasible optimal solution to the entire problem when the last stage is reached [5,6]. Principle of optimality: An Optimal policy has the property that regardless of the decisions taken to enter a particular state in a particular stage, the remaining decisions must constitute an optimal policy for leaving that stage [6,7]. The interest in this work is the distribution of effort problem in dynamic programming which has tremendous and wide application in Engineering development. [6,8].

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2nd International Conference On Engineering Research & Development: 1014 Innovations (15th – 17th April 2008), Benin City, Nigeria

Required algorithm: STEP 1:

Identify the decision variables and specify the objective function to be

optimized

under certain limitations, if any. STEP 2:

Decompose the given problem into a number of smaller sub-problems. Identify the state variable at each stage.

STEP 3:

Write down the general recursive relationship for computing the optimal policy. Decide whether forward or backward method is to be followed to solve the problem.

STEP 4:

Construct appropriate stages to show the required values of the return function at each stage.

STEP 5:

Determine the overall optimal policy or decisions and its value at each stage. There may be more than such optimal policy.

Mathematical model. The mathematical program: n

Maximize Z:



Pi (Xi) functions of a

i 1

single variable and Sn is a known non-negative Subject to: x1 + x2 + x3 + … + xn ≤ Sn with xi ≥ 0 in which P1(x1), P2(x2), …, Pn(xn) are known (non-linear) integer, an important class of multistage decision process. Here, the number of stages is n. We note that: n

fn (Sn, xn) = Pn(xn) + max



Pi (xi)

i  n 1

where the maximum is taken over xn + 1, …, xn such that n

 xi= S , x ≥ 0. n

i

i 1

Thus: Fig (a) stage

state:

stage

n

n+1 xn

Sn

Sn - xn

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2nd International Conference On Engineering Research & Development: 1015 Innovations (15th – 17th April 2008), Benin City, Nigeria

value: fn (Sn,xn)

Pn(xn)

f*n+1 (Sn - xn)

Recursive relation is: fn*(Sn) = Max {Pn(xn) + f*n+1(Sn - xn)} xn = 0,1,…, xn

Numerical Illustration. A certified structural engineer has offers from three reputable company for his services. Each company would like him to work on a full-time basis, however, each company is willing to employ the engineer for as many days of the week as he is willing to give for the fees (in thousand of Naira) shown in the table below. Table I: No. of

Company 1

Company 2

Company 3

0

0

0

0

1

45

20

50

2

70

45

70

3

90

75

80

4

105

110

100

5

120

150

130

days

xi

How many days will the engineer allocate to each company to maximize his weekly income.

Problem Formulation. The three companies forms the three stages. So, xn (n = 1,2,3). The identification of the states may not be readily apparent. To determine the states, we ask questions such as: What is it that changes from one stage to the next? Given that the decisions have been made at the previous stages, how can the states of the situation at the current stage be described? What information about the current state of affairs is necessary to determine the optimal policy hereafter? Sn = number of days still available for allocation to the remaining companies. Sn = 0,1,2,3,4 or 5. Beginning with the last stage (n = 3) we note that the values of P3 (S3) are given in the table and these values keep increasing as we move down the column. Therefore, with S3 days still available for allocation to company 3, the maximum of P3 (x3) is automatically achieved by allocating all S3 days. So pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1016 Innovations (15th – 17th April 2008), Benin City, Nigeria x3* = S3 and f3* (S3) = P3 (S3), as shown in the table below. Table II:

n=3

S3

f3* (S3)

x3*

0

0

0

1

50

1

2

70

2

3

80

3

4

100

4

5

130

5

We now move backward to start from the next-to last stage (n = 2). Here, finding x2* requires computing and comparing f2 (S2, x2) for the alternative values of x2 namely: x2 = 0,1, …, S2. To illustrate we depict this situation when S2 = 2 graphically.

x2

n=3

S2

0 0 50 70 80 100 130

0 1 2 3 4 5

1 20 70 90 100 120

f2(S2,x2) = P2(S2) + f3*(S2 – x2) 2 3 4 5 f2*(S2) 0 50 45 70 95 75 95 115 125 110 125 125 145 160 150 160

x2* 0 0 0 or 1 2 3 4

0

0 45 50 20 2 1

State 0

2

160

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2nd International Conference On Engineering Research & Development: 1017 Innovations (15th – 17th April 2008), Benin City, Nigeria This diagram corresponds to fig (a) except that all three possible states at stage 3 are shown. Thus, if x2 = 0, the resulting state at stage 3 will be S2 – x2 = 2 – 0 = 2 whereas x2 = 1 leads to state 1 and x2 = 2 leads to state 0. The corresponding values of P2 (x2) from the company 2 column in Table I shown along the links and the values of f3* (S2 – x2) from the n = 3 (Table II) are given next to the stage 3 nodes. The required calculations for this case of S2 = 2 are summarized below. Formula: f2(2, x2) = P2(x2) + f3*(2 – x2) P2(x2) is given in the company 2. Column of Table I.

f3* (2 – x2) is given in the n = 3 (Table II) x2 = 0 : f2 (2,0) = P2 (0) + f3*(2) = 0 + 70 = 70 x2 = 1 : f2 (2,1) = P2 (1) + f3*(1) = 20 + 50 = 70 x2 = 2 : f2 (2,2) = P2 (2) + f3* (0) = 45 + 0 = 45 Because the objective is maximization, x22 = 0 with f2* (2) = 70. Table III: We are now ready to move backward to solve the original problem where we are starting from stage 1 (n = 1). In this case, the only state to be considered is the starting state of S1 = 5, as depicted below. 0

0 120

45

125

5 4

State 0

5 160

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2nd International Conference On Engineering Research & Development: 1018 Innovations (15th – 17th April 2008), Benin City, Nigeria Fig (c) Since allocating x1 days to company 1 leads to a state of 5 – x1 at stage 2, a choice of x1 = 0 leads to the bottom node on the right, x = 1 leads to the next node up, then up to the top node with

x1 = 5.

The corresponding P1(x1) values are shown next to the links. The numbers next to the nodes are obtained from the f2*(S2) column of the n = 2 (Table III). As with n = 2, the calculation needed for each alternative value of the decision variables involves adding the corresponding link value and node value, and summarized below.

Formula: f1 (5,x1) = P1(x1) + f2* (5 – x1) P1(x1) is given in the company I column in Table I. f2* (5 – x1) is given in the n = 2 (Table III) x1 = 0 : f1 (5,0) = P1(0) + f2*(5) = 0 + 160 = 160 x1 = 1 : f1 (5,1) = P1(1) + f2*(4) = 45 + 125 =170 .

.

.

.

.

.

.

.

.

x1 = 5 : f1 (5,5) = P1(5) + f2*(0) = 120 + 0 = 120 Therefore

Table IV: x1 S1 n=1

f1(S1,x1) = P1(x1) + f2*(S1 – x1) 0 0 50 70 95 125

1

2

3

4

0 1 2 3 4

45 95 115 140

70 120 140

90 140

105

5

160

170

165

160

155

5

120

f1*(S1) 0 50 95 120 140 170

x1* 0 0 1 2 1 or 2 or 3

1

Conclusion. The optimal solution has x1* = 1, which makes S2 = 5 – 1 = 4, so x2* = 3, which makes S3 = 4 – 3 = 1, so x3* = 1, since f1* (5) = 170, this (1,3,1) allocation of days to the three companies will yield an estimated total benefit of N170,000. These results of the dynamic programming analysis in optimal labour allocation can be summarized graphically below (fig d). An arrow from state Sn to state Sn+1 indicates that an optimal policy decision from state Sn is to allocate (Sn – Sn+1) days to the company n. Allocating the days in this way when following the boldfaced arrows from the initial state to the final state given the optimal solution. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1019 Innovations (15th – 17th April 2008), Benin City, Nigeria Stage

1

2

3 0

0

0

0

0

0

50

50

0

(x3* = 1)

0 1

1

70

20

2 70

0 45

130

2

80

70

95 3

3

(x2* = 3)

80 75

100

4

4

125

100

(x1* = 1) 45

100

5

5

5

170

160

130

State

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2nd International Conference On Engineering Research & Development: 1020 Innovations (15th – 17th April 2008), Benin City, Nigeria References.

[1] F.S. Hiller and K.C. SO ‘On the simultaneous optimization of server and work allocation’ Journal of Operation Research. Vol. 10; No. 2, 1992. [2] A.B. Agbadudu, Elementary Operation Research (Vol. 1), Mudiaga Nig. Ltd; Benin City, 1996. [3] H.A. Taha, Operation Research: Introduction: Macmillian Publishing Co, New York, 1971. [4] S. Kalavaathy, Operation Research (2nd Edition), Vikas publishing house-put Ltd, New Delhi, 2006. [5] W.L. Winston, Operation Research: Applications and Algorithms, Thomson, Asia Ltd, Singapore, 2003. [6] R. Bronson and G. Naadimuthu, Operations Research (2nd Edition: Schaum’s Outlines), Tata McGraw-Hill Ltd, 2005.

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2nd International Conference On Engineering Research & Development: 1021 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08091) The CRAI Model: A framework for managing project knowledge

Dr Paul Ihuoma Oluikpe Department of Civil and Building Engineering, Loughborough University, Leicestershire, LE11 3TU, United Kingdom.

Studies have shown that knowledge management is an enabler of organisational processes and helps achieve projected objectives. This research is aimed at investigating the role of knowledge management in enabling project management to achieve the following objectives---project success, faster completion times, efficiency, innovation, knowledge sharing and best practices. The research conceptual model (The CRAICodification, Reproduction, Assimilation and Interpretation model) focused on four types of primary knowledge needed by projects for successful execution. These are:-Interpretative knowledge, Assimilative knowledge, Reproductive knowledge and Codified knowledge. Using a mixed method approach, qualitative and quantitative data were collected from 303 respondents from project organisations in sectors such as construction, new product design, information technology, manufacturing, information, and water engineering. These organisations are spread in 8 regions of the world. Data were obtained using web questionnaires, structured interviews and organisational documentation. The selection of case studies arose as a result of responses to the online survey. The research used four case studies which exhibited KM consciousness and other criteria which enabled the researcher to identify them as knowledge generating projects. The cases were drawn from Nigeria, Uganda and Cote Devoir. The research applied the CRAI model within these case studies and also compared the results of the survey data with the case study data. The survey achieved a 30.3% (303) response rate. The data gathered were analysed using quantitative analysis tools (SPSS) and techniques (regression, correlation, hypothesis testing, analysis of the model and other general analysis techniques). The survey and case studies focused on identifying best practices, knowledge sharing and management practices, knowledge processes in the project management cycle as reflected by the conceptual model, technology and other aspects of Knowledge Management. Some of the findings made by the research are: (a) No standard best practice exists across the board among projects. Each project has a set of practices that represent best practices for managing their projects; (b) KM was found to be a factor in speeding up project completion times. It was also linked to project success, knowledge sharing, innovation and efficiency; and (c) The CRAI model was found to be applicable to projects and the type of knowledge projects embody. The model positively correlated with each of the expected outcomes-innovation, completion times, efficiency, project success and knowledge sharing. Recommendations made by this research include: 1. Projects should begin to design KM strategies as part of Project Management systems; 2. A project should begin with mapping essential knowledge needed by the project; 3. Project Management should pay closer attention to the existence of communities in the project; 4. KM should be included in the list of critical success factors; and 5. Projects should use PM technologies which integrate KM capabilities.

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2nd International Conference On Engineering Research & Development: 1022 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08284) Dynamic Modeling of Triple Glazing, Single Pass, Single Flow Natural Convection Solar Energy Collector for Agricultural Driers .

D. V. C. Onuoha Asst. Director – Eng’g Services (Mech. Mtce.), Federal Ministry of Environment, Housing and Urban Development Headquarters, Mabushi, Abuja, Nigeria.

ABSTRACT: This paper is used to present the analytical solutions in closed form equations to the energy equations of triple-glazing, single pass and single flow air-heating flat plate solar energy collector with flow between the first cover and the absorber and to be used in agricultural driers. The impetus for the paper was the success of the analytical solution of the single glazing flat plate air-heating collector in being a good representation of the actual collector operation. It is thought that an analytical solution of the triple cover flat plate solar energy collector will generate equations which will be better representations of the actual collector configuration being analyzed. The results of the calculations of the collector output using the generated closed form expressions for the mean temperatures of the plates and outlet fluid and for the collector energy delivery rate, instantaneous and overall efficiencies, showed a marked improvement (over 100%) over the single glazing, single pass and single flow collector with flow between the cover and the absorber (SSSCA flat plate collector). Just as the analytical solution of the SSSCA flat plate collector revealed that the former collector efficiency factor F’ (now called combined plates coefficient of performance, Fp) can be greater than unity, the present analytical solution of the triple glazing single flow flat plate collector has revealed that the collector heat removal factor can be greater than unity – a consequence of the heat trap effect of the covers and the greatly reduced overall heat loss coefficient. The developed closed form equations are simple and straightforward to use, simplifies optimization studies and avoids the iterations inherent in the techniques of past investigators but with results that are believed to be good representations of real collector operations for which better designs can now be made.

NOMENCLATURE coefficient, Wm-2, (eqn. 21) collector area exposed to solar radiation, m2, (eqn. 66) cross-section of fluid flow channel, m2, ( eqn. 79) coefficient, Wm-2, (eqn. (21) coefficient, Wm-2, (eqn. 21) specific heat capacity at constant pressure, Jkg-1K-1 d D dt , eq. (49); hydraulic diameter, m, ( eqn. 79) e heat capacity per unit area, JK-1m-2, (eqn. 49) Fp collector combined plates’ coefficient of performance, ( eqns. 67/68) FR collector heat removal factor, (eqn. 73) g acceleration due to gravity, ms-2 h heat transfer coefficient, Wm-2K-1 IT instantaneous global radiation on a tilted surface, Wm-2, ( eqns. 21) k thermal conductivity, Wm-1K-1 kec cover extinction coefficient, m-1 L latitude, rad; length, m m1, m2, m3, collector temperature time constants, s-1, ( eqns. (55/56) A Ac Af B C cp

ṁf1o fluid mass flow rate, kgs-1, ( eqn. 78) Nu Nusselt Number, (eqn. 103) P pressure, Nm-2 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1023 Innovations (15th – 17th April 2008), Benin City, Nigeria QuD collector energy delivery rate, W, (eqn. 72) QuD.T collector total (daily) energy delivery, MJ, (eqn. 76) t time, s T u UL UT Vf rp           1.0

temperature, K heat transfer/loss coefficient, Wm-2K-1 overall heat loss coefficient, Wm-2K-1, (eqns. 69/70) overall heat transfer coefficient,Wm-2K-1, (eqn. 74) fluid velocity, ms-1, (eqn. 77) absorber plate absorptivity collector tilt, rad length, m emmissivity efficiency dynamic viscosity, Nsm-2 3.141592654 density, kgm-3; reflectivity, ground albedo Stefan-Boltzmann constant, Wm-2K-4 solar transmittivity solar angular frequency = /43200.0 rad.s-1 ,( eqn. 22) INTRODUCTION

The performance of a flat plate collector is usually measured in terms of its instantaneous or overall efficiency. From the analytical solution of a dynamic model of an air heating flat plate solar collector with one glazing material and flow between the glazing material and the absorber plate, (Onuoha, 1997, 2007) the maximum instantaneous efficiency for the non-tracking flat plate collector is less than 0.4 and the overall efficiency is less than 0.35. In order to increase the efficiencies of the flat plate collector, several configurations have been evolved and among them is the use of additional glazing materials beyond the first. However, the use of additional glazing not only complicates the mathematical analysis but also reduce the energy that can be absorbed by the collector even when the glazing material is non-absorbing. From Onuoha (in press, NIJOTECH, a), the optical efficiencies of one-, two-, and three-cover flat plate collector at normal incidence are (çoc = 0.1797, çop = 0.77776), (çoc2 = 0.12273, çoc1 = 0.09685, çop = 0.63751) and (çoc3 = 0.12611, çoc2 = 0.10096, çoc1 = 0.07961, çop = 0.52368) for the same glazing material of 0.004m thick window glass with refractive index of 1.526 and extinction coefficient of 30m-1 for all the collectors and absorber material of mild steel with absorptivity of 0.95 and if the glazing material is non-absorbing, çop = 0.8780, 0.8141, 0.7600, for one-, two-, and three-cover flat plate collectors at normal incidence respectively. Using thin plates theory, (Onuoha, 2007), the analytical solution of the temperatures of an air-heating flat plate collector with three glazing materials can be obtained together with its energy delivery rate and efficiencies. The results of the calculations using the derived equations will justify their applicability in optimization studies and design of better collectors. 2.0 THE COLLECTOR MODEL Fig. 1 shows the cross-section of the solar energy collector under consideration and its thermal energy circuit from which can be written the energy equations (considered as nodal equations) for the element of the collector at a distance x from the fluid entry boundary along the flow direction, and at time t s from start (at 6.00 a.m.) as follows:Tc3 = ITçoc3 – uc3(Tc3-Ta) – hrc3c2(Tc3–Tc2) – hf3c3(Tc3–Tf3) COVER3: (ñcpä)c3 t (1)

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2nd International Conference On Engineering Research & Development: 1024 Innovations (15th – 17th April 2008), Benin City, Nigeria FLUID3: (ñcpä)f3

Tf3 = – hf3c3(Tf3–Tc3) – hf3c2(Tf3–Tc2) t

(2) Tc2 COVER2: (ñcpä)c2 = ITçoc2 – uc2(Tc2-Ta) – hrc3c2(Tc2–Tc3) – hrc2c1(Tc2–Tc1) – hf3c2(Tc2–Tf3) - hf2c2(Tc2–Tf2) t (3) Tf2 FLUID2: (ñcpä)f2 = – hf2c2(Tf2–Tc2) – hf2c1(Tf2–Tc1) t (4) Tc1 COVER1: (ñcpä)c1 = ITçoc1 – uc1(Tc1-Ta) – hrc2c1(Tc1–Tc2) – hrc1p(Tc1–Tp) – hf2c1(Tc1–Tf2) – hf1c1(Tc1–Tf1) t (5) Tf1 Tf1 FLUID1: (ñcpä)f1 + (ṁf1ocpf1/L1) = – hf1c1(Tf1–Tc1) – hf1p(Tf1–Tp) t x (6) Tp ABSORBER: (ñcpä)p = ITçop – up(Tp-Ta) – hrc1p(Tp–Tc1) – hf1p(Tp–Tf1) t (7)

Because of the low heat capacity per unit area of the heat transfer fluid (air), ∂Tf1/∂t = ∂Tf2/∂t = 0 or negligible, and also assuming thin plates, (Onuoha, 1997, 2007), all the remaining partial differentials can be changed to total differentials and we obtain for eqns. (1) – (7): dTc3 (ñcpä)c3 dt = ITçoc3 – uc3(Tc3-Ta) – hrc3c2(Tc3–Tc2) – hf3c3(Tc3–Tf3) (8) 0 = – hf3c3(Tf3–Tc3) – hf3c2(Tf3–Tc2) (9) dTc2 (ñpä)c2 dt = ITçoc2 – uc2(Tc2-Ta) – hrc3c2(Tc2–Tc3) – hrc2c1(Tc2–Tc1) – hf3c2(Tc2–Tf3) - hf2c2(Tc2–Tf2) (10) 0 = – hf2c2(Tf2–Tc2) – hf2c1(Tf2–Tc1) (11) dTc1 (ñcpä)c1 dt = ITçoc1 – uc1(Tc1-Ta) – hrc2c1(Tc1–Tc2) – hrc1p(Tc1–Tp) – hf2c1(Tc1–Tf2) – hf1c1(Tc1–Tf1) (12) dTf1 (ṁf1ocpf1/L1) dx = – hf1c1(Tf1–Tc1) – hf1p(Tf1–Tp) (13) dTp (ñcpä)p dt = ITçop – up(Tp-Ta) – hrc1p(Tp–Tc1) – hf1p(Tp–Tf1) (14) With Tc3 = Tc3(t),Tc2 = Tc2(t), Tc1 = Tc1(t), Tp = Tp(t), and Tf1 = Tf1(x), (15) we can solve for Tf3, (eqn. 9), Tf2 (eqn. 11) and Tf1 (eqn. 13) at any given time t s, (Iyer, 1985, Onuoha, 1997), and get: Tf3 = (hf3c3Tc3 + hf3c2Tc2)/(hf3c3 + hf3c2) (16) pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1025 Innovations (15th – 17th April 2008), Benin City, Nigeria Tf2 = (hf2c2Tc2 + hf2c1Tc1)/(hf2c2 + hf2c1) (17) and Tf1x = ø1Tf1i + (1 – ø1)(hf1c1Tc1 + hf1pTp)/(hf1c1 .+ hf1p) mf1 (18) where the flow parameter, ø1 = exp[-(hf1c1 + hf1p)L1x/( cpf1) (19) and the boundary condition, Tf1 = Tf1i at x = 0, (20) has been used. With IT given by Onuoha (1997; in press, NIJOTECH, a, b) as IT = Acos2ùt + Bsinùt + C (21) where A, B, C are constants and ù = /43200.0 rad.s-1 (22) is the solar radiation angular frequency, substitution of eqns. (16) - (18) into eqns. (8), (10), (12) and (14) will yield, after rearrangement and solving simultaneously, expressions for Tc3, Tf3, Tc2. Tf2, Tc1, Tf1, and Tp (Onuoha, 2007, Jeffery, 1975, Sokolnikoff and Redheffer, 1966) :ec3ec2ec1ep(D + m1)(D + m2)(D + m3)(D + m4)Tc3 = Ac3ccos2ùt + Ac3ssin2ùt + Bc3ccosùt + Bc3ssinùt + ëc3 (23) ec3ec2ec1ep(D + m1)(D + m2)(D + m3)(D + m4)Tc2 = Ac2ccos2ùt + Ac2ssin2ùt + Bc2ccosùt + Bc2ssinùt + ëc2 (24) ec3ec2ec1ep(D + m1)(D + m2)(D + m3)(D + m4)Tc1 = Ac1ccos2ùt + Ac1ssin2ù + Bc1ccosùt + Bc1ssinùt + ëc1 (25) ec3ec2ec1ep(D + m1)(D + m2)(D + m3)(D + m4)Tp = Apccos2ùt + Apssin2ùt + Bpccosùt + Bpssinùt + ëp (26) with the solutions :Tc3 = c3t1exp(-m1t) + c3t2exp(-m2t) + c3t3exp(-m3t) ) + c3t4exp(-m4t) + C3ACcos2ùt + C3ASsin2ùt + C3BCcosùt + C3BSsinùt + ëc3/em (27) Tc2 = c2t1exp(-m1t) + c2t2exp(-m2t) + c2t3exp(-m3t) + c2t4exp(-m4t) + C2ACcos2ùt + C2ASsin2ùt + C2BCcosùt + C2BSsinùt + ëc2/em (28) Tc1 = c1t1exp(-m1t) + c1t2exp(-m2t) + c1t3exp(-m3t) + c1t4exp(-m4t) +C1ACcos2ùt + C1ASsin2ùt + C1BCcosùt + C1BSsinùt + ëc1/em (29) Tp = pt1exp(-m1t) + pt2exp(-m2t) + pt3exp(-m3t) + pt4exp(-m4t) + PACcos2ùt + PASsin2ùt + PBCcosùt + PBSsinùt + ëp/em (30) where em = u4ec3ec2ec1ep = (uc3puc2p-hr32)(uc1pupp-hr12p)-uc3pupphr22 (31) C3AC = (Ac3cAr – Ac3sAi)/Ari, C3AS = (Ac3sAr + Ac3cAi)/Ari (32) C3BC = (Bc3cBr – Bc3sBi)/Bri, C3BS = (Bc3sBr + Bc3cBi)/Bri (33) C2AC = (Ac2cAr – Ac2sAi)/Ari, C2AS = (Ac2sAr + Ac2cAi)/Ari (34) C2BC = (Bc2cBr – Bc2sBi)/Bri, C2BS = (Bc2sBr + Bc2cBi)/Bri (35) pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1026 Innovations (15th – 17th April 2008), Benin City, Nigeria C1AC = (Ac1cAr – Ac1sAi)/Ari, C1AS = (Ac1sAr + Ac1cAi)/Ari (36) C1BC = (Bc1cBr – Bc1sBi)/Bri, C1BS = (Bc1sBr + Bc1cBi)/Bri (37) PAC = (ApcAr – ApsAi)/Ari, PAS = (ApsAr + ApcAi)/Ari (38) PBC = (BpcBr – BpsBi)/Bri, PBS = (BpsBr + BpcBi)/Bri (39) Ar = 16ù4-4ù2u2+u4, Ai = -2ù(4ù2u1-u3), Ari = ec3ec2ec1ep(Ar2 + Ai2) (40) Br = ù4-ù2u2+u4, Bi = -ù(ù2u1-u3), Bri = ec3ec2ec1ep(Br2 + Bi2) (41) uc3p = uc3 + hr3 (42) uc2p = uc2 + hr3 + hr2 (43) uc1p = uc1 + hr2 + hr1 + ø1hf1c1 (44) upp = up + hr1 + ø1hf1p (45) hr3 = hrc3c2 + hf3c3hf3c2/(hf3c2 + hf3c2) (46) hr2 = hrc2c1+hf2c2hf2c1/(hf2c2+hf2c1) (47) hr1 = hrc1p + (1 – ø1)hf1c1hf1p/(hf1c1+hf1p) (48) d e = ñcpä, and D = dt (49) –m1, -m2, -m3, and –m4 are the roots of the equation in D, D4 + u1D3 + u2D2 + u3D + u4 = 0 (50) where u1 = uc3p/ec3 + uc2p/ec2 + uc1p/ec1 + upp/ep (51) u2 = (uc3puc2p-hr32)/ec3ec2+uc3p(uc1p/ec1+upp/ep)/ec3+(uc2puc1p-hr22)/ec2ec1 + uc2pupp/ec2ep+(uc1pupp-hr12)/ec1ep (52) u3 = (uc3puc2p-hr32)(uc1p/ec1+upp/ep)/ec3ec2-hr22(uc3p/ec3+upp/ep)/ec2ec1 + (uc1pupp-hr12)(uc3p/ec3+uc2p/ec2)/ec1ep (53) and u4 = {(uc3puc2p-hr32)(uc1pupp-hr12p)-uc3pupphr22}/ec3ec2ec1ep (54) With -m1 and –m2 as the first and second roots to be determined (by Newton-Raphson Method, for example), then, m3 = ½(u1–m1–m2+m0), and m4 = ½(u1–m1–m2–m0) (55) where m0 = {(u1–m1-m2)2-4[u2+m22–(u1-m1)(m1+m2)]}1/2 (56) The coefficients of the exponential terms are determined by applying the initial conditions: At t = 0 s (6.00 a.m.), pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1027 Innovations (15th – 17th April 2008), Benin City, Nigeria Tc3 = Tc30 = Ta0, and

dTc3 d2Tc3 dt = dt2 = 0

(57) Tc2 = Tc20 = Ta0, and

dTc2 d2Tc2 = 2 =0 dt dt

(58) Tc1 = Tc10 = Ta0, and

dTc1 d2Tc1 dt = dt2 = 0

(59) Tp = Tp0 = Ta0, and

dTp d2Tp dt = dt2 = 0

(60) With hf3c3 = hf3c2 = hf3, hf2c2 = hf2c1 = hf2 and hf1c1 = hf1p = hf1 (61) the enclosed fluid temperatures Tf3 and Tf2 are given by Tf3 = ½(Tc3 + Tc2), and Tf2 = ½(Tc2 + Tc1) (62) The outlet fluid temperature, Tf1o, is given by eqn. (18) with x = L2, i.e., Tf1o = ø1Tf1i + ½(1 – ø1)(Tc1 + Tp) (63) = Tf1i + [(1 – ø1)Fp/2hf1]{[f1(t)/Fpçop + C]çop - UL(Tf1i – Ta)} (64) where the flow parameter, ø1 = exp[-2hf1Ac/(ṁf1ocpf1)] (65) and the collector area exposed to solar radiation, Ac = L1L2 (66) Fp = {hf1c1[(uc3puc2p-hr32)(hr1+uppçoc1/çop)+hr2upp(hr3çoc3+uc3pçoc2)/çop] + hf1p[(uc3puc2p-hr32)(uc1p+hr1çoc1/çop)-uc3phr22 + hr1hr2(hr3çoc3+uc3pçoc2)/çop]}/em (67) = hf1{(uc3puc2p-hr32)[uc1p+hr1+(upp+hr1)çoc1/çop]-uc3phr22 +hr2(hr1+upp)(hr3çoc3+uc3pçoc2)/çop}/em (68) is the combined plates coefficient of performance, UL = {hf1c1[(uc3puc2p-hr32)(uppuc1+hr1up)+hr2upp(hr3uc3+uc3puc2)] + hf1p[(uc3puc2p-hr32)(uc1pup+hr1uc1)-uc3phr22up + hr1hr2(hr3uc3+uc3puc2)]}/Fpem (69) = hf1{(uc3puc2p-hr32)[(upp+hr1)uc1+(uc1p+hr1)up] + hr2(upp+hr1)(hr3uc3+uc3puc2)-uc3phr22up}/Fpem (70) is the collector overall heat loss coefficient, and the temperature time function, f1(t) is given by f1(t) = hf1{(c1t1+pt1)exp(-m1t) + (c1t2+pt2)exp(-m2t) + (c1t3+pt3)exp(-m3t) + (c1t4+pt4)exp(-m4t) + (C1AC+PAC)cos2ùt + (C1AS+PAS)sin2ùt + (C1BC+PBC)cosùt + (C1BS+PBS)sinùt} (71)

2.2 Collector Energy Delivery Rate and Efficiencies. The rate of useful energy delivered by the collector is given by pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1028 Innovations (15th – 17th April 2008), Benin City, Nigeria QuD = (72)

ṁf1ocpf1(Tf1o – Tf1i) = FRAc{[f1(t)/Fpçop + C]çop -UL(Tf1i – Ta)}

where the collector heat removal factor, FR = (1 – ø1) ṁf1ocpf1/UTAc (73) and the overall heat transfer coefficient, UT = (hf1c1+hf1p)/Fp = 2hf1/Fp (74) The instantaneous collector efficiency is given by çci = QuD/ITAc = (FR/IT){[f1(t)/Fpçop + C]çop - UL(Tf1i – Ta)} (75) The collector overall efficiency is given by çco = ∫QuDdt/∫AcITdt ≈ ∑QuD/∑AcIT = QuDT/AcHT (76)

3.

COLLECTOR PERFORMANCE PARAMETERS

3.1 Fluid Velocity and Mass Flow Rate. For the purely natural convection situation under consideration, the velocity and mass flow rate of the heat transfer fluid are as given by Onuoha (in press, NIJOTECH, b) Vf1 = (32ìbL2/ñf1D2){[1 + (ña – ñf1)ñf1D4gsinâ /512ìb2L2]1/2 – 1} (77) and ṁf1o = (32ìbAcäf1/D2){[1 + (ña – ñf1)ñf1D4gsinâ /512ìb2L2]1/2 – 1} (78) where the hydraulic diameter, D = 4Af1/P = 2L1äf1/(L1 + äf1) (79) for flow channel of cross section Af1, perimeter P, width L1, and depth äf1.

3.2. Optical Efficiencies of the Cover and Absorber Plates.. For the three-cover flat plate collector, the optical efficiencies are given by Onuoha (in press, b) as follows:Optical efficiency of Cover3, çoc3 = 1-ñ3-ô3*[1-ñ1*(1-ô3)] (80)

+ ô3*ô2*ô1(1-árp)ôd2**d1*(1-ñd3-ôd3)/[1-ñd3*(1-árp)]}

Optical efficiency of Cover2, çoc2 = ô3*[1-ô2*(1-ñ1)-ñ1*] + ô3*ô2*ô1(1-árp)ôd1*{1-ñd2-ôd2**[1-ñd3+ôd2*ñd3(1-ñd1)]}/[1-ñd3*(1-árp)] (81) Optical efficiency of Cover1, çoc1= ô3*ô2*(1-ñ1-ô1)+ô3*ô2*ô1(1-árp){1-ñd2*-ôd1*[1-ñd2-ôd2**ôd2*ñd3(1-ñd1-ôd1)]}/[1-ñd3*(1-árp)] (82) pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1029 Innovations (15th – 17th April 2008), Benin City, Nigeria Optical efficiency of Absorber, çop = ô3*ô2*ô1árp/[1-ñd3*(1-árp)] (83) The optical efficiencies are calculated separately for each component of the polarization of the reflectivity of light given by ñ┴ = sin2(èi - èr)/sin2(èi + èr) (84) and (85)

ñ║ = tan2(èi - èr)/tan2((èi + èr)

where èi and èr are the angles of incidence and refraction of the radiation at the surface separating the two media (air/transparent cover) respectively. èr is given by Snell’s law, i.e. èr = sin-1{sin(èi)/nr} (86) where nr is the relative refractive index of the two media. At normal incidence, èi = èr = 0.0 and ñ┴ = ñ║ = (nr-1)2/(nr+1)2 (87) At grazing incidence, èi = èr = ð/2 rad, and ñ┴ = ñ║ = 1.0 (88) Bouger’s law is also assumed to operate with the transmission due to absorption given by ôá = e- k / cos r (89) where k is the extinction coefficient of the transparent cover material and ä is its thickness. In eqns. (80) – (83), ñd2* = ñd1+ôd12ñd2/(1-ñd1ñd2) (90) ôd1* = ôd1/(1-ñd1ñd2) (91) ñ1* = ñ2+ô22ñ1/(1-ñ2ñ1) (92) ô2* = ô2/(1-ñ2ñ1) (93) ô3* = ô3/(1-ñ1*ñ3) (94) d1* = d2 + d22d1/(1-d1d2) (95) ôd2** = ôd2/(1-ñd1*ñd3) (96) pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1030 Innovations (15th – 17th April 2008), Benin City, Nigeria ñd3* = ñd2*+ôd1*ôd2*d1d2ñd3/(1-ñd1*ñd3) = ñd2*+ôd2**ôd2*d1*d1ñd3 (97) ñ = ñ(ôá, ñ) = ñ{1+ ôá²(1-ñ)2/(1- ôá2ñ2)} (98) ô = ô(ôá, ñ) = ôá(1-ñ)2/(1 - ôá2ñ2) (99) ñd = ñd(ôád, ñd) = ñd{1+ ôád²(1-ñd)2/(1- ôád2ñd2)} (100) and ôd = ôd(ôád, ñd) = ôád(1-ñd)2/(1- ôád2ñd2) (101)

3.3 Heat Transfer (Loss) Coefficients. The heat transfer coefficients are as given by Onuoha (2007). For the enclosed spaces between the third and second covers and the second and first covers, the fluid-to-cover heat transfer coefficients are given by hf3c3 = hf3c2 = hf3 = Nu3kf3/äf3 and hf2c2 = hf2c1 = hf2 = Nu2kf2/äf2 (102) where the Nusselt Number Nu, is given by Hollands et al (1976) correlation as Nu =1+1.44[1– 1708/Ra.Cosâ]+{1– 1708(sin1.8â)1.6/Ra.Cosâ}+ [(Ra.Cosâ/5830)1/3 - 1]+ for â ≤ ð/3 rad. (103) Only positive values for the terms with the positive radical can be taken. 4. OUTPUT CALCULATIONS, RESULTS AND DISCUSSION 4.1 Input Parameters. 4.1.1 Properties of Air at Low Atmospheric Pressure. From Onuoha (2007), the viscosity ì, specific heat capacity cp, thermal conductivity k, and density ñ, of air in the temperature range 250 ≤ T ≤ 400 K are given by ì = 3.5555E-14T3 – 7.009E-11T2 + 7.9882E-08T – 1.557E-07 Nsm-2 (104) cp = 5.3333E-07T3– 1.676E-04T2 + 6.3333E-03T + 1003.65714 Jkg-1K-1 (105) k = 1.777E-11T3 – 5.257E-08T2 + 1.043E-04T – 7.978E-04 Wm-1K-1 (106) and ñ = 353.0001988T-1 K (107) 4.1.2 Ambient Air Temperature, Ta. From actual measurements it has been found that the ambient air temperature can adequately be represented by a fourth degree polynomial in time, t s: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1031 Innovations (15th – 17th April 2008), Benin City, Nigeria Ta = Ta0 + Ta1t + Ta2t2 + Ta3t3 + Ta4t K for 0 ≤ t ≤ 43200 s (108) 4.1.3

Inlet Air Temperature, Tf1i.

Since (109)

the

input

is

ambient

air,

it

is

reasonable

to

take

Tf1i

=

Ta



t

4.1.4. Daily Global Radiation on a Horizontal Surface, H. From actual measurements on the model day, 23-03-02, H = 12.6 MJm-2. 4.1.5. Other Input Parameters. árp =0.95, â = 0.174533 rad., cpc3 = cpc2 = cpc1 = 840.0 Jkg-1K-1, cpp = 473.3 Jkg-1K-1, äc3 = äc2 = äc1 = 0.004 m, äf3 = äf2 = äf1 = 0.02m, äp = 0.0035m, äib = 0.1925m, äis = 0.07m, åc3 = åc2 = åc1 = 0.94, åp = 0.97, g = 9.81 ms2 , H = 12.6 MJm-2, kib = kis = 0.059 Wm-1K-1, L = 0.0119555 rad (for Nsukka, Nigeria), L1 = 0.94m, L2 = 1.225m, L3 = 0.23m, L4 = 0.028m, L5 0.0715m, n = 82, nrc3 = nrc2 = nrc1 = 1.526, ñc3 = ñc2 = ñc1 = 2720.0 kgm-3, ñp = 7820.0 kgm-3, ñg(ground albedo)= 0.2, ó = 5.6697E-08 Wm-2K-4, èd = 1.047198 rad, Vw = 0.74 ms-1, (for 23-03-02, Ta0 = 298.83499 K, Ta1 = -5.367E-05 Ks-1,Ta2 = 3.1721E-08 Ks-2, Ta3 = -8.571E-13 Ks-3, Ta4 = 5.3463E-18 Ks-4). 4.2 Initial Values. At time t = 0 s (6.00 a.m.), Ta = Ta0, Tc3 = Tc30 = Ta0, Tc2 = Tc20 = Ta0, Tc1 = Tc10 = Ta0, and Tp = Tp0 = Ta0 (110)

4.3 Results and Discussion. The collector output and measures of performance were calculated at 1800s intervals using a computer program written for that purpose. For a particular collector design and day of operation, the input parameters are the global radiation on the collector plane IT, (eqn. 21), and ambient air temperature Ta, (eqn. 108); while the output consists of the temperatures of cover3 Tc3, (eqn. 27), enclosed fluid3 Tf3, (eqn. 62), cover2 Tc2, (eqn. 28), enclosed fluid2 Tf2, (eqn. 62), cover1 Tc1, (eqn. 29), outlet fluid1 Tf1o, (eqn. 63/64), and absorber plate Tp, (eqn. 30), and the collector energy delivery rate QuD, (eqn. 72). The above are displayed in fig. 2. The performance parameters include the optical efficiencies of cover3 çoc3, (eqn. 80), cover2 çoc2, (eqn. 81), cover1 çoc1, (eqn. 82, and absorber plate çop, (eqn. 83), together with the collector combined plates coefficient of performance Fp, (eqns. 67/68), heat removal factor FR, (eqn. 73) and instantaneous efficiency çci, (eqn. 75). These, together with the fluid mass flow rate ṁf1,o (eqn. 78), and outlet velocity Vf1o, (eqn. 77), are displayed in fig. 3. The global radiation and collector optical efficiencies are symmetrical about the solar noon with the global radiation and absorber optical efficiency being a maximum there. Covers 1, 2 and 3 optical efficiencies have local minimums at solar noon. All other parameters possess maximums at different locations. For the plates’ and fluids’ temperatures, the maximum point is between 3600s and 5400s after solar noon. This is attributed to the heat capacities of the materials of the collector and fluid stream, the ambient air temperature, and cross coupling between the cover plates, the fluids, and the absorber plate. These and those of other parameters are summarized in table 1 with the corresponding values for the SSSCA Flat Plate Collector for comparison. Table 2 shows the values of the parameters at 21600s pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1032 Innovations (15th – 17th April 2008), Benin City, Nigeria (noon) as compared with those of SSSCA Flat Plate Collector. The transient temperatures are given by the exponential terms of each TABLE 1. Maximum Values of TSSC1A Flat Plate Solar Collector Model Input and Output Parameters and Measures of Performance on 23-03-02, compared with those of SSSCA Flat Plate Collector. PARAPARASSSCA METER SSSCA TSSC1A TSSC1A METER VALU TIM VALU TIM VALU TIME VALU TIM E E E E E (s) E E (s) (s) (s) IT, Wm-2 493.90 2160 493.90 2160 Vf1o (ms-1) 0.3866 25200 0.2894 2340 0 0 5 3 0 Ta=Tfi,(K) 307.14 3240 307.14 3240 ṁf1,o (kgs-1) 0.0074 25200 0.0058 2160 0 0 4 0 0 Tc3 (K) 320.06 2700 326.98 2520 FP 0.3143 41400 1.0375 2160 0 0 8 6 0 Tf3 (K) 340.65 2700 FR 1.2605 25200 0.4246 2160 0 5 9 0 Tc2 (K) 340.65 2700 çoc3 1.6985 3600, 0.1406 5400, 0 8 39600 6 3780 0 Tf2 (K) 347.67 2700 çoc2 0.1122 7200, 0 3 36000 Tc1 (K) 354.69 2700 çoc1 0.0844 10800, 0 0 32400 Tf1o (K) 353.14 2520 337.47 2520 çop 0.5235 21600 0.7776 2160 0 0 1 8 0 Tp (K) 366.67 2520 356.29 2340 çci 0.7790 34200 0.3332 2520 0 0 2 9 0 QUD (W) 352.73 2520 185.85 2340 çco 0.5369 43200 0.2739 4320 0 0 5 7 0 UL (Wm-2K3.1406 2520 9.6751 2520 UT, Wm-2K-1 4.4465 25200 10.589 2340 1 ) 0 0 8 5 0

Table 2. Comparison of the Output Parameters and Measures of Performance of TSSC1A and SSSCA Flat Plate Solar Collectors at 21600s (noon) on 23-03-02. TSSC1A

SSSCA

Parameter IT, ( Wm-2) Ta=Tfi (K) Tc3 (K) Tf3 (K) Tc2 (K) Tf2 (K) Tc1 (K) Tf1o (K) Tp (K)

TSSC1A

SSSCA

0.379808 0.007354 2.89003 1.257995 0.126206 0.101022 0.079648 0.523511 0.594171

0.289125 0.005801 1.03756 0.42469 0.118057 0.777678 0.325428

Parameter 493.90 305.00 317.56 337.40 337.41 344.45 351.49 350.60 363.90

493.90 305.00 325.86 336.70 355.54

Vf1o (ms-1) ṁf1,o (kgs-1) FP FR çoc3 çoc2 çoc1 çop çci

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2nd International Conference On Engineering Research & Development: 1033 Innovations (15th – 17th April 2008), Benin City, Nigeria QUD (W) UL (Wm-2K-1)

337.92 3.1142

185.078 9.64931

çco UT (Wm-2K-1)

0.407942 4.409214

0.246028 10.56639

Table 3. Maximum Values of TSSC1A Flat Plate Solar Collector Model Input and Output Parameters and Measures of Performance on 23-03-02, compared with the output when the transient terms are deleted. PARAOUTPUT OUTPUT PARAWITH TRANSIENT METER OUTPUT WITH OUTPUT METE TERMS DELETED TRANSIENT

TERMS DELETED VALU E

TIM E (s) 2160 0 3240 0 2700 0 2700 0 2700 0

VALU E

TIME (s)

VALU E

493.90

21600

307.14

32400

320.09

27000

Vf1o (ms1 ) ṁf1,o ( kgs-1) FP

340.67

27000

FR

340.67

27000

çoc3

IT,Wm-

493.90

Ta=Tfi, (K) Tc3 (K)

307.14

Tf3 (K)

340.65

Tc2 (K)

340.65

Tf2 (K)

347.67

2700 0

347.68

27000

çoc2

0.1122 3

Tc1 (K)

354.69

2700 0

354.70

27000

çoc1

0.0844 0

Tf1o (K) 353.14

2520 0 2520 0 2520 0 2520 0

353.15

25200

çop

366.68

25200

çci

352.83

25200

çco

3.1746 8

25200

UT, Wm2 -1 K

0.5235 1 0.7790 2 0.5369 5 4.4465 8

2

320.06

Tp (K)

366.67

QUD (W) UL ( Wm2 -1 K )

352.73 3.1406 2

0.3866 5 0.0074 4 3.1437 7 1.2605 5 1.6985 8

TIM E (s) 2520 0 2520 0 4140 0 2520 0 3600, 3960 0 7200, 3600 0 1080 0, 3240 0 2160 0 3420 0 4320 0 2520 0

VALU E

TIME (s)

0.3867 0 0.0074 4 3.1468 6 1.2606 1 0.1406 6

25200

0.1122 3

7200, 36000

0.0844 0

10800, 32400

0.5235 1 0.7791 0 0.5328 0 4.4467 7

21600

25200 41400 21600 5400,3780 0

34200 43200 25200

equation for the output temperatures – the complementary solutions and are displayed in fig. 4. For each item, it increased rapidly with a maximum at 3600s, a local minimum at 5400s and a local maximum at 7200s and then fell towards zero at the end of collector operation (43200s), loosing significance from 21600s (noon). Deletion of the transient terms did not affect the points of occurrence of the critical values of the parameters in any way but with insignificant or no effect on the values of the parameters themselves as displayed in Table 3, showing that the solutions to the temperatures can be adequately represented by the steady state values. The comparisons shown in Tables 1 and 2 indicate the superiority of the three-cover flat plate collector over its one-cover counterpart. Despite the greatly decreased absorptivity of the absorber plate in the three cover flat plate collector, (çop = 0.523511 against 0.777678 for the SSSCA collector), its efficiency is over twice (0.779 against 0.333) and pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1034 Innovations (15th – 17th April 2008), Benin City, Nigeria its overall efficiency is twice (0.537 against 0.274) that of the SSSCA flat plate collector. It appears that the covers effectively acted as a heat trap with a resultant higher performance of the TSSC1A flat plate collector. This will also account for the heat removal factor of the TSSC1A flat plate collector being greater than unity for several points of the collector operation and with a maximum at 25200s (when the absorber plate temperature, fluid1 outlet temperature and mass flow rate and velocity, and collector energy delivery rate had their maximum values). Expectedly, the overall heat loss coefficient is low and though it started and ended with the same values as the overall heat transfer coefficient, it fell below it for most of the collector operation. With the transient terms deleted, the solution to the plates’ temperatures (eqns. 66-69) become: Tc3 = C3ACcos2ùt + C3ASsin2ùt + C3BCcosùt + C3BSsinùt + ëc3/em (111) Tc2 = C2ACcos2ùt + C2ASsin2ùt + C2BCcosùt + C2BSsinùt + ëc2/em (112) Tc1 = C1ACcos2ùt + C1ASsin2ùt + C1BCcosùt + C1BSsinùt + ëc1/em (113) Tp = PACcos2ùt + PASsin2ùt + PBCcosùt + PBSsinùt + ëp/em (114) The temperature time function (eqn. 71) become f1(t)=hf1{(C1AC+PAC)cos2ùt+(C1AS+PAS)sin2ùt+(C1BC+PBC)cosùt+(C1BS+PBS)sinùt} (115) and all other terms and equations remain as before. 5.0

CONCLUSION AND RECOMMENDATIONS

Equations have been derived for predicting the temperatures of the covers and absorber plates and the dynamic performance of a three cover flat plate air heating solar collector. The steady state plates’ temperatures have also been found to be adequate for calculating the collector output. Unlike the presentation of the past investigators in which the fluid velocity and mass flow rate are independent variables, the fluid velocity and mass flow rate in this presentation are dependent variables (since they are generated by the system). Since the dynamic model gives the collector output and performance as a function of time of day, with the daily global radiation and ambient temperature variable as the only inputs, the derived equations are recommended for use by future designers and investigators using this configuration in solar energy applications as it is believed that an experimental investigation of the collector configuration will prove the derived equations to be adequate.

REFERENCES *Hollands, K. G. T., Unny, T. E., Raithby, G. D., and Konicek, L., (1976) Free Convective Heat Transfer Across Inclined Air Layers, Journal of Heat Transfer, Trans. ASME pp 189 – 193. *Iyer, R. M., (1985), Theoretical Analysis and Performance Evaluation of Agricultural Driers. Proc. Int. Symp. on Thermal App. of Solar Energy. Hakone, Japan. *Jeffery, A., (1975), Mathematics for Engineers and Scientists. E.L.B.S. *Onuoha, D. V. C. (1997), Optimization of Natural Convection Solar Energy Crop Driers – Collector and Drier Optimization. Trans. Int. Conf. on Energy and the Env. Limmasol, Cyprus. *Onuoha, D. V. C.,(2007), Dynamic Modeling of Natural Convection Solar Energy Collectors for Crop Driers I. NIJOTECH, University of Nigeria, Nsukka. *Onuoha, D. V. C., (in press NIJOTECH, a), Optical Efficiencies of One-, Two-, and Three-Cover Flat Plate Solar Energy Thermal Collectors. *Onuoha, D. V. C. (in press NIJOTECH, b), On the Velocity Variable in Natural Convection Air Heating Solar Energy Collectors and Driers. *Sokolnikoff, I. S., and Redheffer, R.M., (1966), Mathematics of Physics and Modern Engineering. McGraw Hill Kogakusha Ltd. Tokyo. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1035 Innovations (15th – 17th April 2008), Benin City, Nigeria

Global Radiation, IT

Glass Cover2 Glass Cover1

Glass Cover3 dx Ta

x

Tc3

HOT

Tf3

Tf1oAIR

Tc2 Tf2 Tc1 Stagnant Air COLD AIR IN

Absorber Plate Insulation

Tf1 Tp Tf1

IT

Ta uc3-1 hf3c3-1 Tc3 Tf3 Tf3 (ñcpä)f3 hrc2c3-1 -1 t hf3c2 ITçoc3 Tc2 hf2c2-1 ITçoc2 Tf2 hrc1c2-1 Tf2-1 (ñcpä)f2 t ITçoc1 hf2c1 T Tc1 hf1c1-1 (ñcpä)f1 f1 + t hrc1p-1 ITçop T -1Tf1 Tf1 P hf1p (ṁf1cpf1/L1) -1 x up (b) Ta

Ta (a)



Fig. 1 (a ) Cross Section of TSSC1A Flat Plate Solar Energy Thermal Collector showing the temperatures at position x and at inlet and outlet fluid flow channels indicated by . (b) Thermal Energy Circuit

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2nd International Conference On Engineering Research & Development: 1036 Innovations (15th – 17th April 2008), Benin City, Nigeria

370

300

330

250 200

320

150 310 100 300

Cover1 Temperature (K) -2

350 340

Cover2 Temperature (K)

Plane (Wm )

400 350

Energy Delivery Rate (W) and Global Radiation on Collector

450

360

Ambient and Output Temperatures (K)

Ambient and Fluid1 Inlet Temperature (K) Cover3 Temperature(K)

500

Absorber Plate Temperature (K) Fluid3 (Enclosed) Temperature (K) Fluid2 (Enclosed) Temperature (K) Fluid1 Outlet Temperature (K) Collector Energy Delivery Rate (W) Global Radiation on Collector Plane (W/sq.m)

50

290 0

0 45000

9000 18000 27000 36000 Time (s) (t = 0s at 6.00 a.m.) Fig. 2. TSSC1A Flat Plate Collector Model Input and Output Parameters on 23-03-02 2

3

4

1.6

0.008

1.4

0.007

1.2

0.006

1

0.005

0.8

0.004

0.6

0.003

0.4

0.002

Collector Heat Removal Factor

0.2

0.001

Collector Instantaneous Efiiciency

0

Cover3 Optical Efficiency Cover2 Optical Efficiency Cover1 Optical Efficiency -1

(kgs )

Fluid1 Mass Flow Rate

-1

and Fluid1 Outlet Velocity (ms

Output Performance Parameters

)

Ta = Tf i = 298.83499 - 5.367E-05t + 3.1721E-08t - 8.571E-13t + 5.3463E-18t .

0 0

9000

18000

27000

36000

45000

Absorber Plate Optical Efficiency Fluid1 Outlet Velocity (m/s)

Fluid1 Mass Flow Rate (kg/s)

Time (s) (t = 0s at 6.00 a.m.)

Fig. 3a. TSSC1A Flat Plate Collector Model Output Performance Parameters I, Fluid1 Mass Flow Rate and Outlet Velocity on 23-03-02

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2nd International Conference On Engineering Research & Development: 1037 Innovations (15th – 17th April 2008), Benin City, Nigeria

4.5 4

3 2.5

1.5 2 1

1.5 1

0.5 0.5 0

Combined Plates' Coefficient of Performance -1

2

-2

3.5

(Wm K )

2.5

Overall Heat Transfer and Heat Loss Coefficients

Combined Plates Coefficient of Performance and Heat Removal Factor

3

Collector Heat Removal Factor Collector Overall Heat Loss Coefficient (W/sq.m.K) Collector Overall Heat Transfer Coefficient (W/sq.m.K)

0 0

9000

18000

27000

36000

45000

Time (s) (t = 0s at 6.00 a.m.)

Fig. 3b. TSSC1A Flat Plate Collector Model Output Performance Parameters II on 23-03-02

5.8 Cover3 Transient Temperature (K) Cover2 Transient Temperature (K) Cover1 Transient Temperature (K) Absorber Plate Transient Temerature (K) Fluid3 (Enclosed) Transient Temperature (K) Fluid2 (Enclosed) Transient Temperature (K) Fluid1 Outlet Transient Temperature (K)

4.8

Temperature (K)

3.8

2.8

1.8

0.8

-0.2

0

9000

18000

27000

36000

45000

-1.2 Time (s) (t = 0s at 6.00 a.m.) Fig. 4. TSSC1A Flat Plate Collector Model Plates' and Fluids' Transient Temperatures on 23-03-02

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2nd International Conference On Engineering Research & Development: 1038 Innovations (15th – 17th April 2008), Benin City, Nigeria

TECHNICAL SESSION 7B: CONSTRUCTION MATERIALS: CONCRETE

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2nd International Conference On Engineering Research & Development: 1039 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08050) EMPIRICISM IN REINFORCED CONCRETE DESIGN

*NWOKOYE D.N and ** EZEAGU C.A * BSc. (Eng.), PhD (Lond.), C. Eng. (UK), FIWSc. (UK), F.IStruct.E. (UK), FICE (UK), FNSE (NIG.), F.NIStruct. E. (NIG.), REG. Engr. (COREN) (NIG.). Professor of Civil Engineering Department, Faculty of Engineering, University of Benin. **B.ENG. (Uniben), M.ENG. (Uniben),Lecturer, Department of Civil Engineering, Faculty of Engineering, University of Benin, P.M.B 1154,Edo State, Nigeria. E-mail: akaolisings @ yahoo.com. GSM nos: 08038766208; 08023454175. INTRODUCTION Constituents of Concrete Concrete is an agglomeration of fine and coarse particles of rock or any other materials (generally referred to as aggregates) bonded together by the cement paste. Concrete is multi-phase material and on the assumption that the cement paste coats and binds all the aggregate particles together. The following phases can be identified: Cement paste phase (cement plus water plus air voids), Mortal phase (cement paste plus fine aggregate or sand),Quasi-Mortar phase (cement paste plus coarse aggregate) (No fine concrete),Concrete phase (cement paste plus fine and coarse aggregates). The concrete phase is thus more complex and heterogeneous than any of the other three phases and its properties among other things would depend on: The properties of the constituent materials in their discrete states.The properties of the different phases constituting the concrete phase and on any interaction between the phases.The relative proportions in which the discrete concrete materials are mixed.The method of compacting, placing and curing the concrete.The age or maturity of the concrete. Some properties of concrete such as strength, elastic modulus and ultrasonic (pulse) on wave through the concrete improve with increasing age and some attaining a ‘near’ constant value after a period of three to twelve months. On the assumption that the aggregates are inert materials, (this is not strictly true) changes in any specific concrete property with age are chiefly due to changes in the hydrating paste phase and these changing are mostly influenced by the type of the cement and the effective water content of the mix. Theoretically, the constituent materials can be proportioned ritually in an infinite number of ways but in practical concrete mixes the aggregates usually form about 60-75 percent by volume of the concrete. Alteration in the mix proportions gives rise to variations in any desired property. A change in the watercement ratio gives rise to changes in strength and other properties. An increase in the sand content decreases the workability of the concrete mix. According to Kaplan1 five percent voids reduced the compressive strength by about thirty percent (i). The method in which the concrete is mixed, placed or cast affects the homogeneity of the mix and in even in some cases induces anisotropy in the finished product. Each concrete mix therefore has characteristics amounting to a pseudo-archetype material. Unlike steel which is manufactured under strict specifications and controlled factory. However but technological expertise is necessary to produce a Structural Concrete. Structural Concrete being defined as concrete produced for structural purposes and having certain expected but specified performance requisites. To this end, great advanced have been made through the field of concrete technology. On reinforced concrete, more variables including the type, quantity, and quality and strain capacity of the reinforcing steel are yet introduced. These are further complicated by the bond characteristics of concrete and steel and by creep and shrinkage properties of concrete. Reinforced concrete therefore is a very complex material and a purely analytic approach to reinforced concrete design is beset by an alarmingly large number off variables. Apparently much success has however been achieved through a combination of three major approaches. These are (1) the Control of Concrete Quality, (2) by the use of Empirical Relationships, (3) by the Analytic Methods. Only 1 and 2 are further considered here. Analytic Methods very often make use of 1 and 2 either in assumptions or in practice. 1.2 Concrete of Concrete Quality pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1040 Innovations (15th – 17th April 2008), Benin City, Nigeria

©

The quality of concrete is assessed both in the fresh and hardened states. Concrete quality can be specified by prescribing the constituent materials, the methods to be used in production and by setting certain standards of quality measurable by performance tests after production. The subject of testing for quality can therefore be divided into, (a) Control testing (b) Compliance testing. Control testing is essential at the production stage. The materials mix proportions and workability must be continually checked. The quality of concrete produced at the mixer is assessed both in the fresh and hardened states. Test on hardened concrete usually involves the use of standard control specimens. At the time of this test which is usually 7 to 28 days after mixing. It is always too late to make any adjustments to the mix proportions relating to the particular concrete. The most popular test is the cube or cylinder crushing strength test. The control tests are to ensure that the concrete being placed in the structure is of the right design ingredients and quality. The main disadvantage of the use of control specimens is that the quality of the concrete in the actual structure might well be different from those of the control specimens. This could arise through standard of supervision and workmanship particularly in placing, compacting and curing of the concrete. Compliance test examines whether the objectives of the control tests and specifications have been achieved. It involves the assessment of the quality of the final product. The engineer must satisfy himself that the work offered conforms to specifications. Strictly, compliance tests ought to relate directly to the strength or the structural performance expectations of the structural elements indirectly determined from cube crushing or cylinder compression tests using standard control specimens or directly from cores cut from the final product or finished work. The crushing strength of the cored samples would of course relate directly to the quality of the concrete in the actual structure but this method is not always economic at all (and might not structurally be feasible) particularly if a statistically representative sample is to be use. In this regard, Nondestructive Testing (NDT) methods can be used to supplement the cube, splitting cylinder, flexural tension and promising of the NDT methods is the Ultrasonic Pulse Velocity method. Compliance tests can therefore be related to tests (destructive or nondestructive) carried out on the actual final product whilst the indirect compliance test would chiefly relate to tests on standard control specimens. Both tests are considered complementary if fully exploited. 1.3 Use of Empirical Relationships Empirical correlations are very widely employed in engineering and in several other fields of applied sciences. Their uses imply a philosophy of experimental approach to engineering problems which otherwise would prove too complex to be practicably solved by analytic methods. Empirical relationship is mostly concerned with predicting a behaviour or result from observations on a chosen variable. The relationship usually provides a norm for future predictions under similar conditions of test. Use of empirical relationships in reinforced concrete or other complex system design is a direct consequence of the complex and variable nature of the materials. From the preceding discussion, it can be seen that quite a large number of variables are involved in concrete making. These variables may be broadly classified into: 1. Independence Concrete Variables, 2.Dependent Concrete Variables, and 3.Pseudo-Independent and Pseudo-Dependent Concrete Variables. 1.1.3 Independent Concrete Variables These can be defined as those parameters which arise from the innate attributes of the constituents and from other factors which influence the desired property of the concrete. These include: (a) Physical, thermal, acoustic, electrical, chemical and mechanical properties of the aggregates but of particular interest are angularity and flakiness, surface texture, elasticity, acoustic properties, density and grading of the aggregates. (b) Type of cement including the physical and chemical properties. Mix proportions and in particular the water-cement ratio, and aggregate cement ratio (d) Age of the concrete. 1.3.2 Dependent Concrete Variables These are defined as those parameters which arise from the desired properties or performance requisites of the concrete and include: Workability of the concrete. (a) (b) Strength – flexural, tensile, torsion, shear and crushing strengths. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1041 Innovations (15th – 17th April 2008), Benin City, Nigeria (c) (c)

Elasticity – dynamic modulus, static modulus, and Poisson’s ratio. Quality – homogeneity, density, durability.

(d)

Acoustic – wave velocity, stiffness constant (defined as the product of density and the square of wave velocity), specific acoustic impedance, attenuation, logarithmic decrement and resonant frequency.

1.3.3 Pseudo-Independent and-Dependent Concrete Variables These are not a new breed of variables. They simply arise from empirical relationships between same classes of variables. are particularly useful in NDT methods of estimating material properties. (Non Destructive Testing). In practice it has been found that some of the dependent concrete variables can be empirically related to each other. This means that certain desired properties of concrete can be assessed or predicted from measurement of some of the independent variables mentioned earlier are not easily determinable and in correlating products and not with the:” LUMPED VARIABLES” or “GROUPED VARIABLES” approach and assumes that all the effects of the variations in the characteristics of the pseudo-independent variable concerned are reflected and characterized by the in measured value pseudo-independent variable. (This is not strictly sohence the variability). The property which is measured is defined as a pseudo-independent variable whilst the other property estimated or predicted from its measurement is considered as pseudo-dependent on the measured property. A pseudo-independent variable which has been of general use in reinforced concrete is the CUBE CRUSHING STRENGTH or in some Countries the CYLINDER COMPRESSION STRENGTH. “THE ULTRASONIC PULSE VELOCITY” as and the STIFFNESS CONSTANTS can also be used as pseudo-independent variable. 1.3.4 Concrete Cube Strength The concrete cube crushing strength has for many years served as index for both the quality and strength of plain, reinforced and prestressed concrete members. A concrete with high cube strength has relatively a high elastic modulus, high flexural strength has therefore been empirically related to several other concrete properties including the static and dynamic Young’s moduli, modulus of rupture, tensile splitting strength, cylinder compression strength and flexural strength. In particular BS 8110 Part 2 1985 (2) has tabulated mean values for the static modulus at 28 days against the 28 day characteristics cube strength for normal weight concrete. BS 8110 Part 2 (2) has also given an empirical relationship between the static modulus Es = 1.25 Ed –19 ……………….(1) Where the dynamic method of test is used to obtain an estimated value for the static modulus; the dynamic modulus E is thus the pseudo-independent variable. Bs 8110 Part 2 (2) states that such an estimated value will generally be correct to within ± 4 kN/mm2. The static modulus/cube strength relationship for normal weight concrete at 28 days is given (2) in equation 17 as E 28 = ko + 0.2 fcu, 28 ……………..(2) Where E 28 is the static modulus of elasticity at 28 days; f 2 cu, 28 is the characteristics cube strength as 28 days (in N/mm ); k 2 o is a constant closely related to the modulus of elasticity of the aggregate (taken as 20 KN/mm for normal weight concrete). BS 8110 Part 2 (2) also gave an equation for static modulus of elasticity at any age as Ec, t = Ec, 28 . Where- t > 3 days R = 0.4 + 0.6

fcut fcu 28

Fcu is the characteristics strength at the age required. 1.3.5 Ultrasonic Pulse Velocity Ultrasonic Pulse Velocity Method for testing concrete is also quite popular and given official recognition since the publication of BS 4408 1974 (3) Part 5 “Measurement of the test, attention has been concentrated on the measurement of pulse velocity which has been concentrated on the index for some properties of concrete. However, attempts to correlate pulse velocity with the cube crushing strength have pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1042 Innovations (15th – 17th April 2008), Benin City, Nigeria not proved very successful. This has been a major drawback to a general acceptance of the method since the cube crushing strength has served as a norm by which a wide range of concrete properties including even the structural performance could be related. The pulse velocity method has several advantages and can be used in-situ to establish the relative quality and strength of concrete in relation to standard requirements. The pulse velocity has also been related to the dynamic and static Young’s moduli of normal concretes. BS 4408 Part 5 (3) gave a table relating static and dynamic modulus of elasticity to pulse velocity. The relationships are empirical (with the pulse velocity as the measurable parameter) and have been stated to apply to concretes made with most types of natural aggregates. The estimate of modulus of elasticity is stated to have accuracy better than ± 10 percent. Whilst the empirical relationship of BS 4408 appear curvilinear, while that recommended by BS 8110 Part 2 as per equation (1) is linear. Nondestructive testing methods chiefly rely on empirical correlation between a measurable nondestructive parameter and the desired property of the material. From BS 8110 the cube crushing strength and the dynamic modulus of elasticity appear as the measurable parameters and are thus the pseudo-independent variables from which the static modulus can be predicted indeed, it might be more convenient to relate both the cube strength and the static modulus of elasticity to the dynamic modulus which is a nondestructive parameter and repeated tests at various ages could be made on the same specimen. In practice concrete strength could either be obtained from standard cube specimens or from cored samples from structural elements. Dynamic modulus measurement and the cube strength tests are usual made on standard specimens whose quality might not be related to the actual quality of the concrete in the structure. Pulse velocity measurements may be repeated without causing any damage to neither the structure nor the material. It could be said that the cube crushing strength test is a mere reference scale since under real structural loading, the concrete is not subjected to just uniaxial compression as in direct compression test. Hadley (4) discussed a paper (in 1950) on the Ultimate strength of Reinforced concrete Beams (5) asked and stated thus: “But why should there be this agreement of flexural strength? What is there about a 6 x 12 in. cylinder to make its strength the precise measure of beam strength? The types of loading are wholly different”. The relationships of the standard cube strength to the standard cylinder compressing strength strengthened to including structural performance are based on empirical correlations. The main disadvantage is that unless the crushing tests are performed on cored specimens, the properties of the concrete in the actual structure might well be different from those of standard specimens. This factor could be reduced and a partial factor of safety. BS 8110 allows for this through a partial factor of safety. This factor could be reduced and thus resulting in better economy if the pulse velocity method of test cannot only exploited but also reduced to a level of understanding acceptable to many engineers. Elvery and Din (6, 7 ) related pulse velocity directly to the structural performance of some reinforced concrete beams and observed that the flexural strength of reinforced concrete beams could be predicted more closely from ultrasonic pulse velocity results than from cube tests under laboratory conditions. Although the ultrasonic pulse velocity method has several advantages over the cube crushing strength, it is very unlikely that the cube crushing strength would be abandoned in the very near future particularly since most codes of practice and standards are based on the cube crushing strength ( or the cylinder crushing strength) and more so since a wide range of concrete properties including the behaviour of structural elements have been related to the cube crushing strength or cylinder compression strength. SOME ASPECTS OF THE WORK. Lack of good correlation between the concrete cube strength and the ultrasonic pulse velocity has largely contributed to the wide gap between the cube and the pulse velocity methods of assessing the concrete properties. In a previous paper (8), it was shown that part of the apparent lack of correlation between the concrete cube strength and the ultrasonic pulse velocity stemmed primarily from the interpretation of the results of the pulse propagation velocity through the cement paste is considered, the cement paste pulse velocity so obtained gave good correlation with the cube crushing strength for the type of aggregate concretes tested, could conveniently be divided into two groups with the results of each group considered under one curve. This behaviour is still unexplained. Evaluation of paste-pulse velocity however, requires knowledge of The volume of the constituents (i) pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! 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2nd International Conference On Engineering Research & Development: 1043 Innovations (15th – 17th April 2008), Benin City, Nigeria (ii)

The appropriate wave velocities characteristics of the coarse and fine aggregates respectively (iii) The appropriate specific gravities of the constituent materials and. (iv) The apparent wave velocity through the concrete. Site evaluation of the paste pulse velocity therefore might present some difficulties particularly where any of the data required in (1) – (iii) above is not known. Ideally, it would be preferable if from nondestructive measurement the cube crushing strength could be estimated without any previous knowledge of the mixproportions and these peculiarities of the discrete concretes. It was therefore decided to examine this further and also to examine. ( a ) the recommendations of BS 8110 1985 (2) and BS 4408 1974 (3) concerning the cube crushing strength and the pulse velocity respectively in relation to the assessment of the static and dynamic Young’s moduli of concrete in the light of some published data, and the cube and bending strengths relationship. (b) Some other non-destructive parameters with a view to assessing their applicability and more so they use/uses in “Trouble Shooting” The investigation is largely concerned with concretes made with certain natural aggregates using ordinary Portland cement and normally cured. Condition C above is considered in part 2 of the work. PART 1:

PREDICTING CONCRETE PROPERTIES.

By *NWOKOYE D.N and ** EZ EAGU C.A * BSc. (Eng.), PhD (Lond.), C. Eng. (UK), FIWSc. (UK), F.IStruct.E. (UK), FICE (UK), FNSE (NIG.), F.NIStruct. E. (NIG.), REG. Engr. (COREN) (NIG.). Professor of Civil Engineering Department, Faculty of Engineering, University of Benin. **B.ENG. (Uniben), M.ENG. (Uniben),Lecturer, Department of Civil Engineering, Faculty of Engineering, University of Benin, P.M.B 1154,Edo State, Nigeria. E-mail: akaolisings @ yahoo.com. GSM nos: 08038766208; 08023454175. Abstract. This paper tends to predict concrete properties by establishing concrete strength from concrete cube strength tests, concrete ultrasonic pulse velocity tests, cylinder compression tests. These tests are related empirically to static and dynamic modulus of elasticity and stiffness constant. From several tests carried out over the years by the authors on concrete strength, It was appreciated that the concrete cube crushing test is destructive test, and the measurement of the dynamic modulus of elasticity is non-destructive test on which repeated number of tests could be made on the same specimen as many times and often as necessary. This cube strength can be related to dynamic modulus as: FC = KeCed. Where C = 884 x 10-7 , K = 7358 x 10-4 ,a = 0.92. And also the Cube Strength can be related to static modulus as FC = 138 x 10-9 E2s.The static modulus can be related to the dynamic modulus asEd = 24.6 x 10-3 E1.33d N/mm2. The dynamic modulus Ed is fundamentally related to pulse velocity V, density D and Poisson’s ratio by the equation Ed = DV2 ( ã+ 4) (ã – 24).This have correlated pulse velocity with the Poisson’s ratio well.Static modulus of elasticity and stiffness constant can be related to the ultrasonic pulse velocity as Eu = 365 x 10-6 V 2.22 N/mm2 The stiffness constant can be related to cube strength as Fc= KeCE1.20 N/mm2 Where k = 7358 x 10-4;C = 857 x 10-8 . this paper therefore conclude that the concrete cube strength and the cylinder compression strength are good empirical indices of several concrete properties including even the flexural strength of reinforced concrete beams. The cube strength has so far been used as a pseudo-independent variable for estimating other properties CONCRETE CUBE STRENGTH IN RELATION TO THE STATIC AND DYNAMIC MODULI OF CONCRETE For normal weight concrete BS 8110 Table 7.2 gives the mean values and typical ranges for the static modulus of elasticity for concretes of various characteristics cube strengths. As discussed in the introduction, the parameters, i.e the cube strength Fc, the static modulus Es and the dynamic modulus Ed arise from desired properties of concrete and are considered as same class of variations. They are important in pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1044 Innovations (15th – 17th April 2008), Benin City, Nigeria reinforced concrete design. Each of the parameters can be used as a pseudo-independent variable for the prediction or assessment of the other two provided good correlation exists between them. The choice of the pseudo-independent variable, i.e the measurable parameter would among other things be influenced by (a) Ease and precision of measurement (b) Versatility and practical advantages. In practice standard control specimens would be cast for each measurement. Testing for the static modulus of elasticity is more time consuming than those for dynamic modulus and compression strength and it might therefore be preferable to consider the static modulus more as a pseudo-dependent variable rather than as a pseudo-independent variable. Cube crushing strength or the dynamic modulus can thus be used as the pseudo-independent variable. Any choice between the two therefore becomes a matter of convenient. It must be appreciated however that whilst the cube crushing test is destructive, the measurement of the dynamic modulus of elasticity is non-destructive and repeated number of tests could be made on the same specimen as many times and often as necessary. 3.1 Cube Strength in Relationship to Dynamic Modulus Figure 1 shows a relationship between the cube crushing strength and the dynamic modulus from published data. (9, 10, 11) An exponential regression curve has been fitted based on the above to the results and it is of the form FC = KeCed …………..(3) Where C = 884 x 10-7 and K = 7358 x 10-4 With a of 0.92. Other results have sincere been plotted in. 3.2 Cube Strength in Relation to Static Modulus Figure 2 (curve A) shows the relationship between the cube crushing strength and the static elastic modulus for some concretes (9,10). The aggregates used are Ham River gravel. Singh (9) described the aggregates used by him as consisting mainly of flint and broken quartz crystals with a small proportion of sandstone of various sizes. Singh (9) tested 100x100x400mm prism specimens whilst Evans (10) used 100x100x500mm prism specimens. Under short term design stress-strain curve BS 8110 Part 1.1985. (Figure 2.1), the initial tangent modulus is given as ES = 5.5 f KN/mm2 Where fcu is the characteristic cube strength and m is a partial factor of safety. If this factor is taken as 1.5, the above equation approximates to Es = 4500 f1/2cu ………………(6) This is in closer agreement with the results of Figure 2 curve A than the mean values given in Table 7.2 of Bs 8110 Part 2 1985. A curve of the form ES = 4200 F1/2C is shown, i.e FC = 23.9 x 10-9E2S N/mm2………………… (8) Curve B in Figure 2 shows the results for two lightweight concretes (9,10). Curve A by a factor of 0.417 at a given cube strength resulting in a relationship of the form FC = 138 x 10-9 E2s ………………. (9) Within the range of the results for the Terlite and Aglite concretes. BS 8110 Part 2 (2) states that for lightweight aggregate concrete the values of static modulus in Table 7.2 should be multiplied by ( w ) 2 2400 where w is the density of the lightweight aggregate concrete in kg/m3. For Terlite concrete the average density was of the order 1810 kg/m3 whilst for Aglite the density was of the order 1769 kg/m3. These respectively give multiplying factors of 0.569 and 0.538 (average 0.554 on E of normal concretes at given cube strengths. These are about 32.9% higher apparent than the multiplying factors of 0.47above. This indicates that for these Terlite and Aglite concretes, for a given cube strength, the recommended factor of ( w ) 2 2400 might overestimate the static modulus. Static Modulus in Relationship to the Dynamic Modulus Figure 3 shows the relationship between the static and dynamic modulus obtained from published ( 9, 10, 11, 12, 13) for natural aggregate concretes. Data BS 8110 Part 2 (2) equation 19 has given a relationship of pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1045 Innovations (15th – 17th April 2008), Benin City, Nigeria equation (1), BS 8110 Part 2 relationship is shown in Figure 3 against some published data. It seems that a curve-linear relationship might be more appropriate than a linear relationship and such might even apply to certain lightweight concretes. For these concretes, a relationship previously established (8) between the dynamic modulus and the stiffness constant is of the form Ed = 97 x 10-3 E1u.20 …………………(10) (where Eu is the stiffness constant discussed later.)And also relationship between static modulus and the stiffness constant Eu shown in from figure 4 a relationship of the form Es = 1095 x 10-6 E 1u.60 …………..(11) Thus eliminating Eu in the above equations gives Ed= 24.6 x 10-3 E1.33d N/mm2 ……………. (12) This derived relationship is shown against the published data in Figure 3 and might also apply to some lightweight concretes. Simmons (14) observed the Es and Ed tended to converge over a range of Ed of 34.584.3 KN/mm2. Evan (10) reported that Stanton (16) found that Es varied from 0.34 Ed at four days to O.76 Ed at six months with little change thereafter and that phileo (17) reported investigations where Es obtained found from flexural test was on some cases stated as exceeding Ed. 4.0

CONCRETE PULSE VELOCITY IN RELATIONSHIP TO THE STATIC MODULUS, DYNAMIC MODULUS AND STIFFNESS CONSTANT The dynamic midolus Ed is fundamentally related to pulse velocity V, density D and poisson’s ratio by the equation Ed = Dv2 ( 1 + 4) (1 – 24) …………….(13) When pulse velocity is empirically correlated with Ed, the effects of density and poisson’s ratio are theoretically ignored. The author (8) had shown that at a given age, the pulse velocity is related to the concrete density. Some investigators (11,14) have correlated pulse velocity with the poisson’s ratio. Bs 4408, Part 5 1974 (3) table 3 gave empirical relationships between static and dynamic modulus of elasticity and pulse velocity and has stated that values given apply to most types of natural aggregates. The estimated modulus of elasticity obtained from table 3, Bs 4408 is stated to have accuracy better than ± 10 percent. 4.1 Dynamic Modulus of Elasticity and Stiffness Constant in Relation to the Ultrasonic Pulse Velocity Figure 5 shows a plot of dynamic modulus against ultrasonic pulse velocity for some concretes (9, 10, 11, 18, 19). This figure in figure 5, the data given in Table 3 of BS 4408 is graphically shown including the ± 10 percent accuracy range. The results for the lightweight aggregates (Terlite, Aglite and Slag) are ignored, (Note: BS 4408 Table 3 does not include lightweight aggregate concretes) BS 4408 recommendation gives a poor estimate of the dynamic modulus in the lower and upper pulse velocity ranges. Although BS 4408 recommendation is deemed to apply to natural aggregates, some results for limestone, trachite, granite, basalt and limestone gravel concretes significantly lie outside the ± 10 percent range. A modified curve shown in figure 5 appears more applicable for these results. This would give a more or less constant dynamic modulus beyond a pulse velocity value of 4700 m/s. It has been stated (8) that stiffness constant Eu is more pulse velocity to changes in the dynamic modulus Ed than pulse velocity measurement alone. The measurement of stiffness constant involves the combined measurements for the density and the pulse velocity. However BS 4408 covers only the measurement of pulse velocity. Although BS 1881 (20) covers the measurement of density, the method described can hardly be employed for the assessment of the density of structural elements and structural members in service. A method is the use of a commercial portable “backscattered gamma ray” gauge. This gauge was used by the Elvery (21) and also by Adil (13). The gauge was used by the author for nondestructive measurement of timber densities irrespective of species (22) . The method has one serious limitation in that it senses only the density of a cylinder of concrete 100mm diameter by 100mm deep. Materials lying outside this core do not significantly influence the gauge readings. Measurement is normally made from a single surface. A more detailed investigation into this method of density measurement can be of value. Incorporation of the combined measurement of density and pulse velocity (in the form Dv2 into Bs 4408 would be very advantageous since the static and dynamic moduli and even the cube crushing strength gave better correlation with the stiffness constant than the pulse velocity alone. However all is not lost. Empirical relationships particularly in the field of nondestructive testing are pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1046 Innovations (15th – 17th April 2008), Benin City, Nigeria very often difficult if not impossible to explain by analytic processes. The Back-scattered Gamma Radiation gauge mentioned earlier was primarily designed to measure steel pipe walls and flat metal sheets thicknesses and the gauge was successfully used to empirically estimate concrete sensitivities and timber densities irrespective of the timber species. It was stated earlier that pulse velocity has been empirically related to density and to poisson’s ratio. Since the stiffness constant appears to be a good index for several properties, (8,15,23) it was decided to plot stiffness constant against pulse velocity, in short, DV2 against V. The result is most interesting and is shown in Figure 6. It includes: (a) The results for the 13 types of natural aggregates tested by Kaplan (19). (For Ed/Eu relationship these aggregates fell into two groups which lie distinctly on two different curves ( 8, 15). (b) The results by Evans (10) and Singh (9) using Ham River gravel. © The results by the author using flint gravelandother crushed rock aggregates. (d) The results by Shacklock and Mc keen (18) using Thames Valley gravel with and without entrained air. The air content by volume ranging from 1.5 to 6.5 percent. (e) The results by Adil (13) on voided concrete with polystyrene inclusions. The relationship is of the form Eu = 365 x 10-6 V 2.22 N/mm2………………(14) It seems that Eu can be estimated by the measurement of approach cannot however be preferred to the actual measurements of the pulse velocity and density. To evaluate (PV2) N/mm2 4.2 Static Modulus of Elasticity in Relation to the Ultrasonic Pulse Velocity Figure 7 is a plot of the static modulus of elasticity against the pulse velocity based on the results by Evans (10) , Sigh (9) and Baron-Hay (12) using Ham River (flint) gravel, Terlite, Aglite and Slag concretes. The relationship given in Bs 4408 (2) Table 3 with the ± 10 percent accuracy is graphically shown. It can be seen that Bs 4408 recommendation might also apply to some lightweight concretes of Terlite, Aglite and Slag. Some results however significantly lie outside the 10 percent upper limit. 5.0

STIFFNESS CONSTANT IN RELATION TO CONCRETE CUBE STRENGTH The concrete CUBE STRENGTH and the CYLINDER COMPRESSION STRENGTH are good empirical indices of several concrete properties including even the Flexural strength reinforced concrete beams. The cube strength has so far been used as a pseudo-independent variable for estimating other properties. In “trouble-shooting” however, it becomes necessary to estimate the cube strength of the suspect material or the structural element. This arises either because the quality of the concrete in actual structure is in doubt or because the strength or the residual strength of the structural element is needs to be known. The pulse velocity and the concrete cube strength relationship is best by a number of factors (19,24,25,26) . Stiffness constant has shown good correlation with both the dynamics modulus and the static modulus. If both the dynamic and static moduli correlate with (a) Each other Fig. 3 (b) The cube strength Fig. 1 and Fig. 2 (c) The stiffness constant, Fig. 4 and Nwokoyes (8) One can anticipate that an empirical relationship might also exist between the cube strength and the stiffness constant. This is the premise on which Figure 8 was based. This is interesting since portable instruments are available for these measurements (8, 13, 21, 22). Irrespective of that, by just the measurement of pulse velocity, Figure 7 or equation 14, the stiffness constant can been estimated and hence the cube strength of insuti concretes and concrete structural elements in service can be estimated without any knowledge of mixproportions and age. The apparent large scatter of results may be attributed to the effects of the several variables which have been lumped together, I.e effects of different mix proportions and ages, aggregate types, etc. It is however clear that empirical correlation exists between the stiffness constant Eu and the cube crushing strength Fc for these concretes. Aggregates group curves can be used.. By eliminating Ed from equations 3 and 10, Fc = KeCE1.20 N/mm2 …….. (15) Where k = 7358 x 10-4 ,C = 857 x 10-8 This curve is shown against since published data in Figure 8 and should strictly apply to the group of concrete as pointed out in previous work (23) is shown in Figure 9.

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2nd International Conference On Engineering Research & Development: 1047 Innovations (15th – 17th April 2008), Benin City, Nigeria 1.

2. 3. 4. 5. 6.

7. 8. 9. 10. 11.

12.

REFERENCES Kaplan, M.F:Effects of Incomplete Consolidation on Compressive and flexural strength, ultrasonic pulse velocity and Dynamic Modulus of Elasticity of concrete. Journal of the American concrete Institute, March 1960, pp 853-867 BS 8110 Part 2: structural use of concrete British Standard code of practise for design and construction NDC 624. 0123/. 4 x 691. 3 1985. Bs 4408 Part 5 1973, 1974. Hadley: 1950 the ultimate strength of Reinforced concrete Beam. Road Research Laboratory. Design of concrete mixes. Second edition. London, HM50, 1950 (reprinted 1955) pp. 16. Road Research Road Note No. 4 Elvery, R.H and Din N.M Ultrasonic inspection of Reinforced concrete flexural members. Symposium on Non- destructive testing of concrete and timber Institution of civil Engineers June 1969 pg 51-58. Elvery, R.H and Din, N.M. An assessment of ultrasonic testing for Reinforced concrete beams. Construction industry research and information Association. Technical Note 4. March 1969. nwokoye D.N. Influence of binary aggregate proportions upon some concrete properties magazine of concrete Research. Vol 27; No 93 December 1975. Singh, B.G. concrete Mix design with continuous and gap graded aggregates. This is submitted to the University of London for the degree of Ph.D. June 1953 pp 80-82. Evans, E.P. The effect of curing conditions on the physical Properties of concrete. This is submitted to the University of London for the degree of Ph.D. August 1960. p. 305. Kaplan, M.F. Flexural and compressive strength of Concrete as affected by the properties of coarse aggregates. Journal of the American Concrete institute. Proceedings Vol 55. No11. May 1959. pp. 1193-1208. Baron-Hay J.H’ Structural properties of light weight concrete, this is submitted for the degree of doctor of philosophy July 1960.

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2nd International Conference On Engineering Research & Development: 1048 Innovations (15th – 17th April 2008), Benin City, Nigeria

N/mm 2

400

P= 3.02% 2

Mu/pbd=272+0.016(Fc)/P

300 2

7 6

P= 1.67%

MU/pbd

M u/bd 2

10 9 8

5 4 3

200 Mu/pbd2=17.5+0.288(Fc)/P

P= 0.72%

2

100

1 5 10 15 20 25 30 35 40 45 50 55 60

10 20 30 40 50 60 70 80 90 100 x102 Fc/P

N/mm2

2

CUBE CRUSHING STRENGTH Fc - N/mm FIG. 1. RELATIONSHIP BETWEEN THE BENDING STRENGTH AND THE CUBE STRENGTHS AT GIVING (3) STEEL AREA RATIOS

2

FIG 2. RELATIONSHIP BETWEEN MU/pbd AND Fc/P

250 P =0.72(3)

400

200

100

200

150

Mu/pbd2 =353- 83178(Fc)/P

RANGEOF EQUATION 6 OVERLAP

M U/pbd

300

Mu/bd2

BASEDONUNDERREINFORCEDEQUATION6

2

N/mm 2

P= 1.67(3) P =3.2(3) AUTHOR(P, VARIED)

100 0.1

RANGEOF EQUATION5

1 2 3 4 5 6 7 8 9 10 2 Fc/P N/mm 2

-3

X10

FIG3;. RELATIONSHIP BETWEEN MU/pbd AND Fc/P

BASEDON BALANCEDEQUATION6

0.15

0.20 P/Fc*100

0.25

0.3 2 mm/N

FIG 4;. COMPARISON OF PREDICTIONS BASED PN EQUATIONS 5 AND 6

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2nd International Conference On Engineering Research & Development: 1049 Innovations (15th – 17th April 2008), Benin City, Nigeria Fc = 6 0

20

50

Mu/bd2

N/mm 2

15 40

10

30 20

5 10 As/bd PERCENT

1 2

4

3

5 6

7

8 9

10 11 12 13 14 15

FIG5;. DEDUCED RELATIONSHIP BETWEEN 2 Mu/bd AND P FORGIVEN Fc

2

N /m m

(Mu/bd)c = 0.375 Fc

15

15

10

10

-6

Pc = 212 2 x 10 Fc

5

5

0

5

10 15 20 25 30 35

C R I TI C A L S T E E L A R E A R A T I O P c P E R C E N T

2

20

40 45 50 55 60 65

Cube Crushing Strenght Fc

FIG 7;. RELATIONSHIP BETWEEN OPTIMUM BENDING STRENGTH CRITICAL STEEL AREA RATIO AND THE AVERAGE CUBE CRUSHING STRENGTH

4%

3%

Mu

8 7 6

130 130 130 130 130 130 130

2%

130 130

1%

130

5 4 3 2 1 0

Mu/bd2

12 11 10 9

N/mm 2

130

130 250 260 270 280 290 300 310 320 330 340 350 360 370280 5

10 15 20 25 30 35

40 45 50 55 60 65 2

CUBECRUSHINGSTRENGTH Fc N/mm

FIG9;. DEDUCED RELATIONSHIP BETWEEN (Mu) AND Fc

2

INTERCEPT “f” N/mm

FIG6;. OPTIMUM BENDING STRENGTH AS A FUNCTION OF PSEUDO CHARACTERISTIC YEILD STRESS

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12 11 10 9

2 (Mu/bd)c =0.163Fcu

12 11 10 9

8

8

7 6

7 6

5 4 3 2

Pc=1142x10 -6Fcu

5 4 3 2

CO RR E S P O NDI NG CR IT ICA L S TE E L AR E A RATI O P c P ER CE N T

OPTIMUM DESIGN STRENGTH MU/pbd N/mm 2

2nd International Conference On Engineering Research & Development: 1050 Innovations (15th – 17th April 2008), Benin City, Nigeria

1 1 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 CHARACTERISTIC CUBE STRENGTH fcu N/mm2 2 FIG.8 RELATIONSHIPS BETWEEN MU/pbd c, Pc and Fcu

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2nd International Conference On Engineering Research & Development: 1051 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08051) PART 2: CUBE AND BENDING STRENGTH RELATIONSHIPS.

*NWOKOYE D.N and ** EZEAGU C.A * BSc. (Eng.), PhD (Lond.), C. Eng. (UK), FIWSc. (UK), F.IStruct.E. (UK), FICE (UK), FNSE (NIG.), F.NI.Struct. E. (NIG.), REG. Engr. (COREN) (NIG.). Professor of Civil Engineering Department, Faculty of Engineering, University of Benin. **B.ENG. (Uniben), M.ENG. (Uniben),Lecturer, Department of Civil Engineering, Faculty of Engineering, University of Benin, P.M.B 1154,Edo State, Nigeria. E-mail: akaolisings @ yahoo.com. GSM nos: 08038766208; 08023454175. Abstract: This paper describes a fundamental study of the relationship between the cube crushing strength and the bending strength of singly reinforced concrete beams. With the current practice, the bending strength is

 MU  (i.e. the ultimate moment divided by the product – breadth times the 2   bd 

defined by the parameter 

square of the effective depth of the beam). This parameter is then correlated with either. (a) the cube crushing strength Fc for a given steel area ratio P or (b) The steel area ratio P for a given cube strength. This practice is criticized on the grounds that (1) It does not fully reflect the flexural failure modes and it is therefore not of sufficient general application. (2) It gives rise to multiple curves depending on the cube strength level or the steel area ratio level. Based on regression analysis, equations are established covering the under- reinforced and ‘balanced’ failure modes. The governing parameters are

(

MU F P ), ( C ) and ( ). It is shown that the relationship of (a) and (b) above are particular solutions 2 Pbd P FC

and have therefore been deduced from a general equation. Criteria are also deduced for assessing whether a beam is over-reinforced, under-reinforced or balanced and for evaluating the theoretical margin of safety against over-reinforcement. The steel area ratio to yield an optimum strength ( is defined as the critical steel area ratio PC. At this ratio, both (

MU )c bd 2

MU ) c and Pc are linearly related to the bd 2

concrete cube strength. This relationship can form a basis for simple design curves. Behaviour of flexural members If a simply their forced concrete is progressively loaded to failure, the following sequence of events occur. Phase1: Initially, (1) The distribution of longitudinal strains over any vertical section is a straight line from maximum compression at top surface to maximum tension at the bottom. (2) Strains in the longitudinal reinforcement are equal to those in the concrete surrounding it. (3) The values of all strains at any cross section are very nearly proportional to the external banding moment there. (4) Deflections and rotations increase in virtually direct proportion to the external load. The behaviour of the beam is primarily determined by its cross section and the characteristics of the concrete. The reinforcement being only lightly stressed has little effect. PHASE II : At some stage the tensile resistance of the concrete at the bottom of the beam in the region of maximum moment is overcome and cracks form there and extend upward into the tensile zone. From the above point onward cracks appear progressively nearer the supports and the earlier cracks widen As crack occurs at a section, the concrete ceases to make significant contribution to the tensile force which is thus transferred to the main longitudinal reinforcement causing a considerable increase in the steel strain. As the load is increased, the deflection and rotation of the beam still increase in more or less direct proportion to the load but at a faster rate than in the uncracked state. Linearity of strain distribution of vertical sections is also maintained. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1052 Innovations (15th – 17th April 2008), Benin City, Nigeria PHASE III: As the load is increased beyond working loads, the strains at the extreme compression zone increase into the markedly curved range of stress-strain relationship for concrete and the behaviour of the beam in terms of strains and deformation begin to deviate somewhat from the earlier linear pattern. The third and final phase of the beams response to load is initiated when the strain the longitudinal tensile reinforcement in the region of maximum bending moment reaches the value corresponding the yielding of the steel. Once this happens, increases in applied moment can no longer be balanced by increases in the force in the steel. This necessitates an increase in the lever arm and the upward shift of the neutral axis which reduces the area of concrete in compression. The area of compression zone is soon reduced to such an extent that the limiting stress conditions arise in it and this determines the maximum resistance moment. A concrete compression zone can withstand considerable deformation during this last phase and the central part of the beam becomes in effect a plastic hinge, undergoing, large deformation for very small increases in load until in the end the concrete begins to spall off and if the load in maintained the member fails. If the beam contained a large amount of tension reinforcement it would be possible for the force in the concrete compression zone to reach its limiting value before the tension reinforcement yielded. Such an over-reinforced beam is uneconomic and Phase III above which is essentially due to the yielding of the steel would not take place and thus no warning by large deformation of the impending collapse beam. For this reason when a beam is designed for a bending moment requiring high percentage of tension reinforcement, it is also provided with compression reinforcement which increases the strength of the compression zone and allows the main steel to yield. To ensure that the steel does infact yield first giving adequate warning of impending failure, BS8110 clause 3.3.5.1) [1] the depth of the compression block is limited to half the effective depth. MODES OF FAILURE AND ULTIMATE CONCRETE STRAIN The attainment of these stages particularly stage III would depend on the mode of reinforcement. There cases can be examined as; (1) BALANCED SECTION. (II). UNDER-REINFORCED SECTION. (III) OVER-REINFORCED SECTION. 1. BALANCED SECTIONS: A balanced section is one for which steel yields as the concrete reaches its ultimate strain. Thus the beam simultaneously fails in flexural compression and tension. Using the design curves, (a) Ultimate concrete strain = 0.0035. (b) Minimum yield strain in steel exceeds 0.002 and can be taken as approximately equal to åcu for convenience. For a balanced section therefore the neutral axis therefore is approximately at the centre of effective depth although a better value but less convenient value is X = 0.6d. åcu ≅ 0.0035

x

d- x ≅ 0.5d

Figure 1 UNDERREINFORCED SECTION: With this section, the steel becomes overstressed and yields. The increased load is provided for by increase in the lever arm. The neutral axis rises until the concrete finally fails in compression.

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2nd International Conference On Engineering Research & Development: 1053 Innovations (15th – 17th April 2008), Benin City, Nigeria

åcu

x

ås

Figure 2 Although the final collapse occurs due to crushing of the compression zone, the primarily cause of failure is the yielding of tensile reinforcement which allows the cracks in the concrete to widen and progressively reduced the depth of the compress zone. (III) OVER-REINFORCED SECTION: The steel remains in the elastic range behaviour while the concrete strains without increasing its moment. This is essentially due to the descending portion of the concrete stress-strain Curves. Thus the neutral axis falls while the concrete rapidly strains to failure.

å x

ås

å Figure 3 ULTIMATE CONCRETE STRAIN We have seen from the consideration of all the three modes of failure that the strain at the extreme concrete fibre reaches its ultimate value before flexural failure occur.

åcu

åS3 ås1

ås2

Figure4:TENTATIVE STRAIN PROFILE FOR COLLAPSE

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2nd International Conference On Engineering Research & Development: 1054 Innovations (15th – 17th April 2008), Benin City, Nigeria GENERAL SECTION EQUATIONS Flexural cracking moment Mcr:. Before cracking any influence of reinforcement many be neglected. Stresses vary linearly at the section. Mcr = FtubS - (3) Where S is the elastic section modulus = bh2/ 6 for a rectangular beam Ftub = flexural tensile strength of concrete = approx 1.5 Ftu1 PHASE 1 åcc ≤ åcoI

óc

åc

PHASE II

x

h

d óc ≤ ftub

åc ≤åy óc ≤ E Sås

Figure 5

Figure 6

PHASE III

óC= óCD

åCD < åCC< åCu x

åCC = åCD ƒy

å s> åy Figure 7 In the remaining phases the continuing linear distribution of strain is from maximum compressive Ex at the compressed surface to a tension Es at the level of the steel.

Tensile force in the main reinforcement Ns = As Es Ex (d – x) in the elastic range …(4) Ns = As fy in the yield range …….

(5)

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2nd International Conference On Engineering Research & Development: 1055 Innovations (15th – 17th April 2008), Benin City, Nigeria Note.For cold worked steel, values in the intermediate range can be obtained from the stress-strain curve. Strain in the concrete compression zone at any level ‘y’ above the neutral axis is ås ås

=

d -x x

The corresponding stress is ócy = óco

2 Ecy

2

for Ecy ≤ Eco

-

-

(6)

Eco

Or ócy = óco for Ecy < Ecy ≤ Eco (7) The total compressive force on concrete Nc = ∫o ócy by dy Where by is the breadth of the compression zone at the level ‘Y’ COMPRESSION REINFORCEMENT If compression reinforcement is present its strain = strain in the surrounding concrete. E1s = (X – d1) Ecc X Force in it is thus Ns1 = As1 EsEcc (x – d1 ) -(9) In the elastic range and Ns = As1Fy ………(10) in the yield range LONGITUDINAL EQUILIBRIUM If there is no external axial loading Nc + Ns1 = Ns………( 11) Note: For known cross-sectional details the underfined quantities are Ecc and x using the condition for normal equilibrium of equation (11), x can be expressed in terms Ecc. With this done the force Nc, Ns1 and Ns can be evaluated and the line of action of Nc can be located by integrating the moment about the neutral axis of the forces on small elements in the compressive zone. Hence ỹ = X – ∫y=oócy byYdy ∫y=oócy byYdy Where ỹ is the depth from the compressed surface to the line action of Nc MOMENT OF INTERNAL FORCES The moment of internal forces which must balance the external moment is M = Nc (d- ỹ) + N1s (d – d1)……... (13) The above approach is fairly of general nature so long only flexure is concerned. Using a 3.02 percent steel area ratio have been plotted on these result lies closely against the 3 percent theoretical curve. To theoretically evaluate what happens beyond the practical limits of figure 3 the curve say for the 20 N/mm2 crushing strength of figure 5 has been extended into the OVER-REINFORCED range. This is show dotted in figure 5 and at first shows an approximately constant strength values over a range of steel area ratios, beyond which the strength begins to increase with increasing steel area ratio. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1056 Innovations (15th – 17th April 2008), Benin City, Nigeria Although the deduced curves of figure 4 show the attainment of maximum strengths at the critical steel area ratios and a slight drop beyond those points followed (as per 20 N/mm2 curve) by an approximate constant strength values and further increase in strength at increasing steel areas ratio, in practice these small changes might be masked by the effect of high variability associated with the materials. An anticipated experimental curve would probably show at first, an increase in the strength/steel area relationship (for a given cube strength) up to the critical steel area ratio beyond which changes in the steel area ratio might indicate no significant effect on the bending strength. In concluding this section, it must be emphasized that the general relationship of figure 8 is a curve but a regression line has been fitted in the range of practical interest. Figures 9 and 10 are yet to be so confirmed. These two curves are of great practical interest. As stated in the introduction, Elvery and Din [2,3] have correlated the ultrasonic pulse velocity with the flexural strength(Mu /bd2 ) For this relationship Elvery and Din [2,3] obtained a cubic polynomial regression curve with variable constants which depended on the tension steel area ratio. This of course means of different curve for different steel area ratios. Elvery and Din [2,3] have compared the cubic polynomials with the exponential relationships of the cube strength. With the flexural strength and have concluded that “the flexural strength of reinforced concrete beams can be predicted more closely from ultrasonic pulse results than from cube tests under laboratory conditions …” In the light of the preceding results, it is doubtful whether the above statement is still valid. Din(3) has suggested some design charts relating (Mu/ bd2) to the tensile steel area ratio for a given cube strength and also for a given pulse velocity. The two charts are quite similar in characteristics and preference for pulse velocity to cube strength as the index for the flexural strength is not very apparent. When assessing the flexural strength, it is necessary to be able to predict whether the beam is underreinforced, balanced or over-reinforced. This has been established with the cube strength as the index of the flexural strength but has not been done with the pulse velocity. Elvery and Din [1,2] have carried out an important pioneering work in the field of ultrasonic assessment of the structural performance of some reinforced concrete elements. There is still a need for further detailed and fundamental study in this area. A research programme is being directed towards this objectives. CONCLUSIONS 1. The relationship between (Mu/Pbd2) (P/ Fc ) and or (Fc/ P) is of more general application than that between (Mu/pd2) and Fc or P and gives rise to a single curve which in the latter case would have meant a family of curves. The latter relationship is infact a particular case which is deducible from the relationship between the former parameters. The experimental equations based on regression analysis are justified by flexural failure analysis of singly reinforced rectangular concrete beams. 2. For these results, the equation representing the under-reinforced mode of failure was found to be valid in the range of(P/ Fc ) given by 0.4x10-3 ≤ (P/ Fc ) ≤ 2.79x10-3 mm2/Nand for “balanced” mode of failure 1.24x10-3 ≤ (P/ Fc ) ≤ 2.79x10-3 mm2/N Whilst for over-reinforced mode P/ Fc > 2.79x 10-3 mm2/N or (Fc) less than 358 N/mm2.The range of PRACTICAL INTEREST is therefore 0.4x 10-3 ≤ (P/Fc) ≤ 2.79x 10-3 since over-reinforced condition is best avoided. 3. Analysis of the general equation obtained showed that an OPTIMUM condition exists at (Mu/pbd2) = 176.5 and (P/Fc) = 2.12x10-3 for a constant cube strength and variable steel area ratio. This is confirmed by simply selecting from the experimental curve several levels of (Mu/pbd2) and the corresponding (P/Fc) values; then assigning values to Fc and plotting P against (Mu/bd2). The value of ‘P’ at the optimum condition is defined as the critical steel area ratio Pc for maximum strength (MU/bd2) c. 4. If the tensile steel reinforcement is kept at the critical area ratio Pc, then both the optimum strength and the critical steel area ratio are linearly related to the cube crushing strength. It is suggested that this can be exploited to evolve simple design curves based on optimum conditions. The theoretical margin of safety against over-reinforcement can be assessed. At 90 percent exclusion limit, the optimum bending strength is given by (Mu/bd2) = 185 x 10-3fcu and Pc = 1.22 x 10-3fcu whilst the calculated margin of safety against over-reinforcement is 1.53.

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2nd International Conference On Engineering Research & Development: 1057 Innovations (15th – 17th April 2008), Benin City, Nigeria 5. By applying the same method used in obtaining the optimum conditions from the regression equation to equation 1 of CP110 1972(7) which is similar in form, the results showed that the maximum value of the bending strength is given by (Mu/bd2) c = 198 x 10-3fcu At a critical steel area ratio of Pc = 455 x 10-3 (Fcu/Fy) Whilst the critical steel area ratio is dependent on the type and characteristic yield stress of the steel, the optimum strength is apparently independent of these and depends only on the concrete strength. This is contrary to the results obtained in the investigation which showed a dependence of both the critical steel area ratio Pc and the optimum bending strength on the pseudo characteristic yield stress of the steel. The governing equation can be expressed as (Mu/bd2 ) = pfy – Bf2yP2/Fcu

M u/bd 2

10 9 8 7 6

P= 3.02%

P= 1.67%

5 4 3 2

P= 0.72%

1 5 10 15 20 25 30 35 40 45 50 55 60 2

CUBE CRUSHING STRENGTH Fc - N/mm FIG. 1. RELATIONSHIP BETWEEN THE BENDING STRENGTH AND THE CUBE STRENGTHS AT GIVING (3) STEEL AREA RATIOS

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2nd International Conference On Engineering Research & Development: 1058 Innovations (15th – 17th April 2008), Benin City, Nigeria P =0.72(3)

400

N/mm 2

P=1.67(3) P =3.2(3) AUTHOR(P, VARIED)

300

Fc = 60

20

Mu/pbd2 =353- 83178(Fc)/P

Mu/bd2

100

N/mm 2

Mu/bd2

50

15

200

RANGEOF EQUATION 6 OVERLAP

RANGEOF EQUATION5

40

10

30 20

5

1 2 3 4 5 6 7 8 9 10 2 Fc/P N/mm

10

-3

X10

As/bd PERCENT

1 2

2

FIG8;. RELATIONSHIP BETWEEN MU/pbd AND Fc/P

3

4

5 6

7

8 9

10 11 12 13 14 15

FIG9;. DEDUCED RELATIONSHIP BETWEEN 2 Mu/bd AND P FORGIVEN Fc

2

N /m m

(Mu/bd)c = 0.375 Fc

15

15

10

10

-6

Pc = 212 2 x 10 Fc

5

5

0

5

10 15 20 25 30 35

C R I TI C A L S T E E L A R E A R A T I O P c P E R C E N T

2

20

40 45 50 55 60 65

Cube Crushing Strenght Fc

FIG10;. RELATIONSHIP BETWEEN OPTIMUM BENDING STRENGTH CRITICAL STEEL AREA RATIO AND THE AVERAGE CUBE CRUSHING STRENGTH

References 1 .BS 8110, Structural use of reinforce concrete structures. part 1,2,3. 2 Elvery, R.H and Din N.M Ultrasonic inspection of Reinforced concrete flexural members. Symposium on Non- destructive testing of concrete and timber Institution of civil Engineers June 1969 pg 51-58. 3. Elvery, R.H and Din, N.M. An assessment of ultrasonic testing for Reinforced concrete beams. Construction industry research and information Association. Technical Note 4. March 1969.

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2nd International Conference On Engineering Research & Development: 1059 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08082) TAKING LATERITIC SOILS FOR GRANTED IN HIGHWAY DESIGN AND CONSTRUCTION IN SOUTHERN NIGERIA

OLUJIDE OMOTOSHO, Ph.D. UNIVERSITY OF PORT HARCOURT, NIGERIA.

ABSTRACT Soil materials either in the natural or improved or stabilized form constitute a minimum of about 70% by volume of a road pavement structure comprising subgrade, (or the natural soil material upon which the road is built) and the other artificially-placed layers including sub-base, base-course and wearing course. And by its widely reported wide-spread occurrence and hardening potentials, lateritic soils are the most widely used for roads and other embankment construction in the tropics. But soil investigation component/input in most highway design standards is minima – limited to only classification and CBR characteristics. As a result, true or actual potentialities of lateritic soils are not fully optimized in highway design and construction. Resultant effect of this are prematured (even before half the design year elapses) failure including potholing, pavement breakdown, etc. – a commonplace in southern Nigeria. In this study, samples of lateritic soils found within the Niger delta region (often referred to as deltaic lateritic soils) were used to investigate these potentialities for optimum exploitation in highway design and construction. In natural or unstabilised forms, deltaic lateritic soils were found to possess soaked-CBR which only meets subgrade requirements while stabilizing them with sand produced materials suitable only as sub-base materials. Plain cement stabilization produced base-course materials but with cement contents far in excess of 12% which is rather too high and economically unviable. However and with addition of sand to soilcrete (i.e. cement-sand stabilization), cement requirement to achieve same base-course materials was reduced to about 6%. Stabilising with geosta and cement produced good results at very low geosta content of between 1% and 2% which is cost-advantageous. 1.0 INTRODUCTION Roads in southern Nigeria - whether federal, state or rural – have been in deplorable state most especially in the rainy season when some of them even become impassable. Several reasons have been given for this poor state of the roads by cross-section of the Nigerian society including the press, politicians (especially those in opposition to the ruling party or parties) and the larger public. These reasons include (among others) misplaced priorities by all tiers of government, political victimization especially in states not controlled by the party at the centre, corruption in high and low places, shoddy jobs by unscrupulous contractors who though not qualified for such sensitive/specialized jobs but still enjoy party patronage anyway. Although these are cogent factors but the major factor is often ignored or taken for granted – and that is the nature, state and characteristics of the soil materials upon and with which the roads are constructed. Whereas most soil materials in northern Nigeria tend to satisfy relevant engineering requirements (in their natural forms) for road construction, reverse is the case for their southern counterparts thus making roads construction to be cheaper in the north than in the south. But despite this, the federal government often makes the mistake of allocating to each state about same amount per kilometer of road. Fig. 1 shows a typical road pavement structure or cross-section comprising (from the topmost) the wearing course upon which vehicles actually travel followed by the base-course, the sub-base and finally the subgrade materials (upon which the entire road pavement structure is constructed). Most highway design standards including FMW(1973,1997) employ the soaked-CBR of underlying layers (starting from the subgrade) to determine the thickness of each of the overlying layers in the road pavement structure. Generally and depending on the road type, soil materials either in the natural or stabilised forms constitute between 70% and 100% of an entire road pavement structure. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1060 Innovations (15th – 17th April 2008), Benin City, Nigeria C

L

Shoulder

Wearing course

Cut

Base-course

Fill

S u b-b a s e Modified

subgrade

S u b g r a d e or f o u n d a t i o n

soil

Fig. 1. Typical road pavement structure Lateritic soil group blankets (and that to considerable depths) over 50% of the tropics (Bawa, 1957; Uehara, 1982) hence over 50% of the tropical roads are constructed on and with it. A distinct product of chemical decomposition of some parent rock-forming minerals in presence of rain water, lateritic soils are rich in kaolinite and mostly yellowish to reddish brown in colour depending on the relative proportions of iron and aluminium sesquioxides which dictates its super-sensitivity including hardening potentials (Buchanan,1807; Alexander and Cady,1962; Queiroz de Carvalho, 1991 among others). In the Niger delta region of southern Nigeria, lateritic soils (mostly referred to as “deltaic lateritic soils”) are found to varying but location-dependent thicknesses (ranging from 6.0m to above 30.0m) within the dry and flatland/plains (hatched) of the region as delineated by Akpokodje(1987) and shown in Fig. 2. They have been the most widely used soil materials for construction of road and other embankments within the region. This is because soil materials predominating within the other zones of the delta are much less stable and less useful for such purposes (Arumala and Akpokodje, 1986). For instance, the superficial silty-clay deposits of the freshwater zone are highly expansive and have been a failure in road construction while the chicoco mud of the mangrove swamp zone is rather too soft and highly compressible for any effective engineering application (Omotosho et al, 2003; Omotosho and Akpokodje, 2003; Omotosho, 2005; Omotosho, 2005a). LEGEND Sampling location

© ©

© © ©©© ©©

Fig. 2. Niger delta region and delineation by Akpokodje(1987)

In spite of the apparent relative stability and wide-spread utilisation of the deltaic lateritic soil group generally in road embankment construction, end results have been a mixture of minor successes and higher rates of failure. For instance, these materials are found to generally possess natural soaked-CBR of between 5% and 12% (Omotosho, 2006) which makes them only suitable as subgrade materials in roadworks except if stabilized. But several road bases have been constructed with these materials unstabilised leading to different degrees of failure, while a road in the early 90’s over-stabilised with geosta and cement failed woefully within just one rainy season cycle (Omotosho and Eze-Uzomaka, 2007). Also, roads constructed on and/or with these soils have been generally observed to develop progressive pot-holes sometimes even starting within the first rainy season cycle after construction. This effect is also known to be more severe at pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1061 Innovations (15th – 17th April 2008), Benin City, Nigeria deep road cuts or where embankment is constructed with lateritic materials from deep borrow-pits (Akinsiku, 1991). It is as if the relatively immatured soils at depth (Little, 1969; Tuncer and Lohnes, 1977; Townsend, 1985, etc.) suddenly get over-excited upon exposure to soil-forming conditions near surface hence the fast deterioration through pot-holing. This and many other failure experiences over the years cast doubts on the assumed relative stability of lateritic soils in road construction. And results of the rather minima soil investigation commonly involved in highway design do not showcase these pedology-related failure modes and problems. This paper reviews various studies (spanning about a decade) so far carried out on natural potentialities of deltaic lateritic soils and how they can be improved through various forms of stabilization for road design and construction. 2.0 MATERIALS AND METHODS For the various studies, deltaic lateritic soil samples were collected from eight (8) different active and dormant borrow-pits all scattered within the dry flatland/plains of the Niger delta region as shown in Fig. 2. Samples were generally yellowish-brown to reddish-brown in colour and were air-dried for about two weeks to take advantage of the aggretating potentials of lateritic soils generally upon exposure (Allam and Sridharan, 1981). Table 1 shows the result of preliminary/classification tests on the samples. Table 1. Result of preliminary tests on soils SAM- LOCATION % FINES LIQUID PLASTI PLASTICIT PLE (wet LIMIT, C Y INDEX, sieving) LL (%) LIMIT, PI (%) PL (%) 1 Artillery area, 39.3 35 21.4 23.6 Aba Road, Port Harcourt 2 Rumuodara, Port 44.8 53.6 29.6 24.1 Harcourt 3 Eneka, near Port 47.1 35.8 22.5 13.3 Harcourt 4 Choba 41.3 49.5 23 26.5 5 Emuohua 39.4 55.2 23 32.2 6 Ibaa 32.9 46 16 30 7 Ahoada 36.8 35.6 15.3 20.2 8 Ndoni 36.4 39.4 18.9 20.2 The cement used in these studies was the OPC type while the sand was the coastal plain type both purchased from the common building materials market in Port Harcourt. The geosta-A on the other hand was obtained from the stock belonging to Rivers State Ministry of Works in Port Harcourt – remnant of that used for the construction of Ada George Road in 1991. In the various studies, the soil samples were stabilized mechanically with or without sand addition while proctor compaction was carried out on the mixture. The resulting maximum dry density (MDD) and optimum moisture content (OMC) were used to compact specimens for soaked-CBR tests. The samples were also stabilized with controlled quantities (as percentages of the air-dried soil) cement, cement and sand and cement and geosta. For each of these mixtures, Proctor compaction tests and corresponding soaked-CBR tests were carried out on the specimens. Samples from two of the locations were also heated at different temperatures ranging from about 400C (air-drying atmospheric temperature) to 6000C in a furnace. 3.0 DISCUSSION OF RESULTS Omotosho(2006) found that deltaic lateritic soils generally possess natural soaked-CBR of between 5% and 12% which is only suitable for use as subgrade materials in roadworks.

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2nd International Conference On Engineering Research & Development: 1062 Innovations (15th – 17th April 2008), Benin City, Nigeria 3.1 Sand stabilization When stabilized with controlled quantities of sharp sand, Omotosho(2008) observed that at best achievable are materials suitable for use as sub-base materials in roadworks. And particularly for MDD and sand content, Fig. 3 was obtained.

Fig. 3. Maximum dry density and sand stabilisation This figure not only shows that sand stabilization of deltaic lateritic soils is density dependent but also that MDD maximizes at different sand content for the different soil samples (of different percentage fines). These maximum points could be referred to as the optimum sand content (OSC) beyond which it becomes counter-productive. Table 2 shows OSC for the four samples and the corresponding MDD(kg/m2, OMC (%) and soaked-CBR (%). Table 2. Optimum sand content and sand stabilisation Sample % Optimum Corresponding No. Fines sand content MDD (kg/m3) (%) 1 39.3 46 2007 2 44.3 35 1950 4 41.3 69 2250 8 36.4 50 2086

Corresponding OMC (%)

Corresponding CBR (%)

11.8 13.6 9.2 10.4

31 18 30 34

Values in this table were used to develop a general graphical model for sand stabilization of deltaic lateritic soils shown in Fig. 4. From this table and with percentage fines known from simple wet sieving, OSC, MDD, OMC and soaked-CBR can be directly read off.

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2nd International Conference On Engineering Research & Development: 1063 Innovations (15th – 17th April 2008), Benin City, Nigeria (%)

35

Soaked-CBR

40

30

 27% 25

20

15

(%)

20

30

40

50

60

70

30

40

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60

70

20

30

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content

12

14

 12.2% 10 8 20 2.5

2.4 2.3 2.2 2.1 2

 2000kg/m3

1.9

dry

1.8 1.7

M a x.

density

( M g / c u. m )

O p t.

16

m o i s t.

18

1.5

1.6

Percentage

fines

50 45 40 35 30 25

Opt im u m

s and

conte nt

( %)

Fig. 4. Sand stabilization model pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1064 Innovations (15th – 17th April 2008), Benin City, Nigeria

3.2

Plain cement stabilisation

Fig. 5 shows the result of plain cement stabilization for five of the samples used in this part of the study.

220 200 180

bearing

160 140

100

S1 (F=39.3)

California

ratio

(%)

240

80

S3 (F=47.1)

60

S4 (F=41.3)

40

S5 (F=39.4)

20

S7 (F=36.8)

120

0 0

2

4

6 Ce m e nt

8 conte nt

10

12

14

16

( %)

Fig. 5. FMW soaked-CBR and cement stabilisation

This figure shows FMW-soaked-CBR increasing continually but non-linearly with increasing cement content. It also gave the cement content to achieve the required soaked-CBR of 180% (for use as basecourse materials) varying from 12.5% to 16% as shown in Table 3. This is grossly unviable economically considering the high cost of cement and the large volume of materials usually involved in road earthworks. The reality on ground is that most cement stabilization earthworks within the delta region are priced for about 8% maximum cement content which does not meet the specifications. Table 3 Cement requirements for FMW specification Sample Percentage Cement content for No. fines, F 180% CBR 1 39.3 16 3 47.1 15.2 4 41.3 14.8 5 39.4 12.5 7 36.8 16

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2nd International Conference On Engineering Research & Development: 1065 Innovations (15th – 17th April 2008), Benin City, Nigeria 3.3

Cement-sand stabilization

Fig. 6 summarises the result of stabilizing the soil samples with cement and sand 200

25%

0% sand

50%

10% sand 20% sand

160

25% sand 40%

30% sand 40% sand

120

50% sand

20%, 30%

80

10% 40

0%

0 0

2

4 C e me n t

6

c o n t e n t

8

( %)

Fig. 6 Cement-sand stabilization of deltaic lateritic soils From this figure, it can be seen that sand addition reduces cement requirement. Infact, base-course materials can be generally achieved with about 40% sand and 6% cement. Thus what plain cement stabilization could not achieve economically, composite cement-sand stabilization could. 3.4 Cement-geosta stabilization Experience with Ada George Road linking Mgbuoba and Mile 3 areas within Port Harcourt metropolis in the early 1990s gave rise to this part of the study. The sub-base of this new road was massively stabilised with geosta and cement probably without much technical control. This led to an unprecedented massive, rapid and widespread failure of this road pavement structure within just one rainy season cycle after being exposed to vehicular traffic. In the study by Omotosho and Eze-Uzomaka(2007), samples from locations 1 and 4 (Table 1) were stabilized with controlled quantities of cement and geosta, compacted to standard Proctor test and resulting MDD and OMC used to compact specimens for soaked-CBR tests. Fig. 7 shows the result. 100 8%(S1) 90

S1, 2% cement 6%(S4)

S1, 4% cement

80

S1, 6% cement 6%(S1), 4% (S4)

S1, 8% cement

70

S4, 2% cement

60

S4, 4% cement

4%(S1) 50

S4, 6% cement

2%(S1)

40 30 20 10 0 0

1

2

3

4 Geosta

5 co ntent

6

7

8

9

10

( %)

Fig. 7. CBR and geosta-cement stabilisation pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1066 Innovations (15th – 17th April 2008), Benin City, Nigeria From this figure, it can be observed that geosta addition gave considerable improvement in soaked-CBR over plain cement stabilisation but at very low geosta contents not greater than 2%. This limit must have been exceeded in the construction of Ada George Road leading to lower CBR and hence the unprecedented and massive failure that resulted. 4.0 CONCLUSION Contrary to the apparent relative stability and wide-spread use of deltaic lateritic soils in road construction, this study brings out the associated problems that could emerge if their natural properties (usually inferior to the minimum requirements for road pavement structure) are taking for granted. REFERENCES Akinsiku, K.A. (1991). “Road failures in Nigeria – a geotechnical appraisal,” Unpublished B.Sc. Research Project Report, Civil Engineering Department, University of Port Harcourt, Port Harcourt. Akpokodje, E.G. (1987). “The engineering-geological characteristics of major superficial soils of the Niger delta,” Eng. Geol. (Amsterdam), 23, 193-211. Alexander, L.T. and Cady, J.G. (1962). “Genesis and hardening of laterite in soils,” Tech. Bull. 1282, US Dept. Agric., 90. Allam, M.M. and Sridharan, A. (1981). “Effect of wetting and drying on shear strength,” J. Geotech. Engrg., ASCE, 107(4), 421-438. Arumala, J.O. and Akpokodje, E.G. (1987). “Soil properties and pavement performance in the Niger delta,” Qtr’ly Journal of Engrg. Geol., London, 20: 287-296. Bawa, K.S. (1957). “Lateritic soils and their engineering characteristics,” J. SMFE, ASCE, 83(4), paper 1428. Buchanan, F. (1807). A journey from Madras through the countries of Mysore, Canara and Malabar, East Indian Coy., London, 2, 436-460. Federal Ministry of Works (1973). Highway Manual (Part I): Design, Federal Ministry of Works and Housing, Lagos, Nigeria. Federal Ministry of Works (1997). General Specifications (Roads and Bridges), Vol. II, Federal Ministry of Works and Housing, Lagos, Nigeria. Little, A.L. (1969). “The engineering classification of residual tropical soils,” Proc., Spec. Sess., 7th ICSMFE, 1, 1-10. Omotosho, O., Akpokodje, E.G. and Imoniyabo, J. (2003). “Untapped potentials of chicoco: the apparently unsuitable but promising soil of the Niger delta,” Scientia Africana, 2(1/2), 43 – 56. Omotosho, O, and Akpokodje, E.G. (2003). “Improving quality of cohesive soils through drying: a case study of chicoco soil of the Niger delta,” Proc., 1st Nigerian Drying Symposium, University of Port Harcourt, Nigeria, 1, 15-26 Omotosho, O. (2005). “Lime stabilization of the chicoco mud of the Niger delta,” Global J. Engrg. Research, 4(1&2), 69-73. Omotosho, O. (2005a). “Influence of geosta addition on cement-stabilised chicoco mud of the Niger delta,” American J. Env. Sc., 1(1), 59-63. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1067 Innovations (15th – 17th April 2008), Benin City, Nigeria Omotosho, O. (2006). “Effects of stabilization on the performance of deltaic lateritic soils as road pavement materials,” Unpublished Ph.D. thesis, University of Nigeria, Nsukka, Nigeria. Omotosho, O. and Eze-Uzomaka, O.J. (2007). “An appraisal of the performance of geosta as a stabilizing agent for deltaic laterite in sub-base construction,” J. Geol. & Geotech. Engrg., 25: 575-579. Omotosho, O. and Eze-Uzomaka, O.J. (2008). “Optimal stabilization of deltaic lateritic soils,” Under review for publication by Journal of SAICE, South Aftica Queiroz de Carvalho, J.B. (1991). “Lateritic soils: chemical and geotechnical properties,” in Blight et al (eds.), Geotechnics in the African environment, A.A. Balkema, Rotterdam, 3-6. Townsend, F.C. (1985). “Geotechnical characteristics of residual soils,” J. Geotech. Engrg., ASCE, 111(1), 77-94. Tuncer, E.R. and Lohnes, R.A. (1977). “An engineering classification for certain basalt-derived lateritic soils,” Eng. Geol. (Amsterdam), 11, 319-339. Uehara, G. (1982). “Soil science for the tropics,” Proc., ASCE Geotech, Engrg. Spec. Conf., ASCE, N.Y.

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2nd International Conference On Engineering Research & Development: 1068 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08121) DURABILITY-BASED APPROPRIATENESS OF SAWDUST CONCRETE FOR RIGID PAVEMENT O.M. Ogundipe O. M.(1) and Y.A. Jimoh(2) Civil Engineering Department, University of Ado-Ekiti, Nigeria. [email protected], 08033867536 (2) Civil Engineering Department, University of Ilorin, Kwara-State. (1)

ABSTRACT In this paper, sawdust concrete with nominal mixes 1:1:2, 1:1½:3, 1:2:4, 1:3:6 and 1:4:8 were subjected to durability test. The 28-day water absorption of the mixes are 5.69, 8.97, 8.29, 7.83 and 11.11%, 28-day linear shrinkages are 0.67, 0.50, 1.83, 1.83 and 1.95%, respectively. The 28-day thermal conductivities are 0.229, 0.232, 0.229, 0.223 and 0.176W/m.K., respectively. The 28-day compressive strengths of mixes 1:1:2 and 1:1½:3 are 18.33 and 8.78 N/mm2, respectively, while their 28-day flexural strengths are 1.71 and 1.33 N/mm2, respectively. These values indicated that they are good and durable concrete and can be used for construction of rigid pavement. KEYWORDS: Sawdust, concrete, durability, rigid, pavement. 1.0 INTRODUCTION Concrete durability has been defined by the American Concrete Institute as its resistance to weathering action, chemical attack, abrasion and other degradation processes [1]. It is very important that concrete should be able to withstand the conditions for which it has been designed without deterioration. Durability of concrete is limited by the environment to which the concrete is exposed or by internal causes within the concrete itself [1]. The external causes can be physical, chemical, or mechanical. However concrete mixes are not normally tested for durability directly; instead, concrete specifications frequently contain mix requirements, which are designed to provide durability by ensuring that the set concrete attains a minimum strength, either compressive or flexural [2]. But a further thought has revealed the main properties that do affect the durability of structures to include (i) permeability, (ii) occurrence of micro-cracks in the concrete due to heat of hydration of cement and related stresses, (iii) carbonation and (iv) passivity film of reinforcement and chances of corrosion [2]. In concrete, strength and durability are not necessarily or directly dependent on each other, more so when high grade cement is used [3]. Strength alone cannot ensure durability, which means durability is another factor for performance assessment. In fact, the approach to durability studies has been outlined by [4] to include: (i) complete and proper definition of the environment, (ii) characterization of the material in the form of appropriate index values, and (iii) test methods to ensure that the requisite index values have been met [5]. Portland cement concrete is widely available throughout the world, but the technology and the skill to design mix (proportioning), mixing, placing and curing for long-term durability has not yet spread as widely as is necessary [3]. It was stated further that every concrete mixture should be proportioned in accordance with exposure conditions, construction considerations, and structural criteria [3]. Also, judicious selection and use of chemical admixtures will continue to enhance the durability of concrete. Improvement in the control of concrete production will also enhance durability of concrete [3]. Durability of concrete is mainly a question of transport properties and chemical composition. The transport properties are a function of porosity and cracking. If one reduces porosity and eliminates cracking or keeps the cracks width very small durability will increase [6]. The porosity of lightweight aggregate provides a source of water for internal curing of the concrete that provides continued enhancement of concrete strength and durability [7]. Indeed, the appropriateness of sorptivity property as a durability criterion and service life predictor has been demonstrated [7]. The major external sources of the mechanism for internal restructuring of concrete are the environmental factors of temperature, heat transport, weather and climate (wind, humidity, etc), water and other deleterious compounds (sulphates, chlorides, etc.). Hence, an assessment of the influence of these pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1069 Innovations (15th – 17th April 2008), Benin City, Nigeria factors on the sawdust concrete is highly desirable. It will ensure the needed confidence in applying emerging materials for conventional use; in this case rigid pavement. Hence, water absorption test, linear drying shrinkage, thermal conductivity, compressive and flexural strength tests were carried out to evaluate the durability of sawdust concrete. 2.0 MATERIALS AND METHODS 2.1 Materials The materials consisted of (i) sawdust, (ii) river sand, (iii) Ordinary Portland cement and (iv) water. The sawdust was obtained from Adeparusi Sawmill in Opopogboro, Ado-Ekiti, whose water absorption, density and specific gravity values are 96.9%, 260 kg/m3 and 0.68, respectively [8]. Zone 2 river sand mined from a nearby stream in Ado-Ekiti was sampled from a construction site at Ado. Its specific gravity is 2.38 while its density is 1550 kg/m3, initial moisture content is 11.80% and silt content is less than 6% [8], hence appropriate for concrete works. Ordinary Elephant Portland cement produced by the West African Portland Cement Company located at Ewekoro, Ogun State was purchased from a depot in Ado-Ekiti. Water fit for drinking, World Health Organization (WHO) standards compliant, was the mixing water. The particle size distribution of the sawdust shown in figure I complied with the grading for lightweight aggregates structural concrete.

Figure I: Particle size distribution curve of sand and sawdust 2.2 Methods Test specimens of cubes, beams and cylinders were produced with nominal mixes 1:1:2, 1:1½:3, 1:2:4, 1:3:6, and 1:4:8 from the other conventional concrete materials Portland cement, fine aggregate (sand) and water, but the coarse aggregates replaced with sawdust. The proportioning, mixing and production of test specimens have been fully described [8]. The tests were carried out in accordance with the following standards; Water absorption of concrete [9], linear shrinkage [10], thermal conductivity [11], compressive strength [9] and flexural strength [9]. The sizes of the specimens were as follows: Cube: 150 mm  150mm 150 mm Beam: 1000 mm 150mm 150 mm Cylinder: 100 mm  110 mm The corresponding test equations are reproduced below: Water Absorption =

W1  W2  100% ……………... (1) W2

where W1 = Weight after soaking W2 = Saturated dry weight SL =

L  100% ………………………………….. (2) G pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1070 Innovations (15th – 17th April 2008), Benin City, Nigeria where, SL = Linear drying shrinkage percent. ∆L = Change in the linear dimension of the specimen due to drying from a saturated condition to the equilibrium weight and length G = Test specimen gage length K=

qL ………………………………………. (3) A(t1  t 2 )

where, K = Thermal conductivity (W/m.k) q = Btu/h flowing into the calorimeter (temperature rise in degree Kelvin of the water flowing through the calorimeter times the weight of flowing water, W. L = thickness (distance between hot junctions at which t1 and t2 are Measured), t1 = Higher of two temperature measured in the test specimen, Kelvin. t2 = Lower of two temperatures measured in the test specimen, Kelvin. A = area of center calorimeter, m2 Compressive strength =

P …………………………... (4) A

where, P = Maximum load at failure A = Sectional area of the concrete specimen

R

PL ……………………………………………. (5) bd 2

where, R =Flexural Strength or Modulus of rupture, (N/mm2) P = Maximum applied load indicated by the testing machine, (N) L = Span length, mm b = average width of specimen, mm d = average depth of specimen, mm

3.0 RESULTS AND DISCUSSION The test results of water absorption, linear drying shrinkage, compressive and flexural strengths were shown in figures II-V, respectively. Three samples were tested and the average was calculated. 3.1 Water absorption As shown in figure II, the water absorption values of all the mixes decrease with age. The 28-day water absorption of nominal mixes 1:1:2, 1:1½:3, 1:2:4, 1:3:6 are 5.69, 8.97, 8.29 and 7.83% respectively. They are less than 10%, except that of nominal mix 1:4:8 with a value of 11.11%. This indicates that they are good concrete [1]. The range of value of water absorption of the mixes also indicates that they can be used for structural purposes and rigid pavement inclusive, since they have values between 5-30% [12, 13].

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2nd International Conference On Engineering Research & Development: 1071 Innovations (15th – 17th April 2008), Benin City, Nigeria 25

WATERABSORPTION(%)

20

15 1:01:02 1:11/2:3 1:02:04 1:03:06 1:04:08 10

5

0 0

5

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AGE (DAYS)

Figure II: Water absorption against age 3.2 Linear drying shrinkage Figure III shows the linear shrinkage of all the mixes. The linear drying shrinkage for nominal mix 1:1:2 for all the ages ranges from 0.33-0.83%. Nominal mix 1:1½:3 has the drying shrinkage values in the range 0.25-1.00%. The linear drying shrinkage of nominal mixes 1:2:4, 1:3:6 and 1:4:8 have values between 0-92-1.92, 1.13-1.92, and1.17-2.17%, respectively. The values in the range 0.04-0.15% was given by [12] for structural concretes. The drying shrinkage values for all the mixes are well above this range indicating that they may not be suitable for structural purposes. Also, [10] required that the drying shrinkage of structural concrete be less than 0.07%. 2.5

LINEAR DRYING SHRINKAGE (%)

2

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1

0.5

0 0

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AGE (Days)

Figure III: Linear shrinkage against age 3.3 Thermal Conductivity The thermal conductivity of the concrete of all the mixes decreases with age, as shown in Table 1. Concrete with nominal mixes 1:1:2, 1:1½:3, 1:2:4 and 1:3:6 have 28-day thermal conductivities of 0.229, 0.232, 0.229, and 0.223 W/m.K, respectively. These indicate that they could be used for structural purposes and rigid pavement inclusive, since they have values between 0.202-0.576W/m.K. [12, 13]. The low thermal conductivity values make the concrete good construction material.

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2nd International Conference On Engineering Research & Development: 1072 Innovations (15th – 17th April 2008), Benin City, Nigeria Table 1: Thermal conductivity of various mixes Age 1:1:2 1:2:4 1:3:6 1:4:8 1:1½:3 (days W/m. W/m. W/m. W/m. W/m.K ) K K K K 7 0.251 0.236 0.229 0.225 0.212 14 0.242 0.216 0.196 0.176 0.197 21 0.219 0.243 0.207 0.242 0.217 28 0.229 0.232 0.229 0.223 0.176 35 0.219 0.223 0.233 0.220 0.222

3.4 Compressive strength Figure IV shows the compressive strengths of the mixes against age. This shows that the compressive strengths of all the mixes increase with age except mixes 1:2:4 and poorer where the values dropped after 28 days. This could be due to insufficient amount of hydrolyzed cement to adequately cover the large surface of the sawdust. The 7 and 28-day compressive strengths of concrete of nominal mix 1:1:2 are 11.11 N/mm2 and 18.35 N/mm2 respectively. These values meet the strength requirement for grade 12N/mm2 mass concrete and can therefore be employed for the construction of rigid pavement surfacing and as cement bound base material for trunk roads [14]. Also concrete of nominal mix 1:1½:3 has 28-day compressive strength of 8.78 N/mm2 which can be used as grade 7 lightweight concrete for use in rigid pavement.

25

20

STRENGTH (N/mm2)

15

1:01:02 1:11/2:3 1:02:04 1:03:06

10

COMPRESSIVE

1:04:08

5

0 0

5

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15

20

25

30

35

40

-5 AGE (Days)

Figure IV: Compressive strength against age

3.5 Flexural strength The flexural strengths increase with age for all the mixes as shown in figure V. The 28-day flexural strength of concrete of nominal mix 1:1:2 is 1.71 N/mm2, which is greater than1.4 N/mm2 specified [15]; hence it can thus be used for base of rigid pavement. It can be seen that the concrete mixes have flexural after 7 days. This confirms the late development of tensile properties of concrete.

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2nd International Conference On Engineering Research & Development: 1073 Innovations (15th – 17th April 2008), Benin City, Nigeria

FLEXURAL STRENGTH (N/mm2)

2.5

2

1.5

1:01:02 1:11/2:3 1

1:02:04 1:03:06 1:04:08

0.5

0 0

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40

-0.5 AGE (Days)

Figure V: Flexural strength against age 4.0 CONCLUSION In this work, sawdust was examined for use in concrete pavement, the concrete produced with nominal mixes 1:1:2, 1:1½:3, 1:2:4, 1:3:6, and 1:4:8 were subjected to the following tests, water absorption, linear shrinkage, thermal conductivity, compressive strength and flexural strength tests. The following conclusions were reached (1) Concretes produced for all the mixes except nominal mix 1:4:8 have28-day water absorption values less than 10%. This indicates that all the mixes not leaner than 1:3:6 will stand the test of time for durability criteria. Also they are in the range suggested by [12] for rigid pavement. (2) The thermal conductivity values of the concrete confirm that they are suitable for use as rigid pavement material. (3) The results showed that mixes 1:1½:3 and richer could meet the strength requirement for grade 12 N/mm2 and 7 N/mm2 mass concrete and could therefore be employed for the construction of rigid pavement surfacing and as cement bound base material for trunk roads.

5.0 REFERENCES Neville A.M., 1981. Properties of Concrete. Pitman Books Limited, Third Edition, 1981. Bhanumathidas N. and Kalidas N. 2, Fly Ash for Quality Upgradation and Better Life Cost. Website. (2005) Tilkalsky P.J., Bryant M. and Jan O., “Concrete Durability”. A2E01: Committee on Durability of Concrete, 2001. Alexander, M.A. and Ballim, Y., “Experiences with Durability Testing of Concrete: A Suggested Framework Incorporating Index Parameters and Results from Accelerated Durability Tests”. Proceedings, Third Canadian Symposium on Cement and Concrete. (1993), Pp 248-263. Bentz D.P., Ellen M.A., Ferraris C.F. and Garboiz E.J., . Sorptivity based life predictions for Concrete Pavements. Proceedings, International Society for Concrete Pavements. Vol I, Orlando Florida,(2001) Pp 181-193. Reinhardt H.W., Concrete with Enhanced Durability. Website, 2005

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2nd International Conference On Engineering Research & Development: 1074 Innovations (15th – 17th April 2008), Benin City, Nigeria NRMCA,. National Ready Mixed Concrete Association, “Structural lightweight Concrete” Concrete in Practice CIP36, 2003. Ogundipe, O. M., An Investigation into the Use of Sawdust for Rigid Pavement Works. M.Eng thesis. University of Ilorin, Department of Civil Engineering, Kwara-State, Nigeria, 2006. ( Unpublished) American Society for Testing and Materials ,. Construction (Concrete and Mineral Aggregates.) Vol. 04.02, 1983. American Society for Testing and Materials,. Construction (Chemical-Resistant Materials; Vitrified Clay, Concrete, Fiber-Cement Products; Mortars; Masonry.), 1983. American Society for Testing and Materials, General Products, Chemical Specialties and End Use Products (Refractories; Carbon; Graphite Products; and Activated Carbon), 1983. Washa, G.W., Properties of lightweight aggregates ad lightweight concrete. Journal of the American Concrete Institute, No 4, Vol. 58, (`1956) Pp 375-382. Joo-Hwa Tay and Woon-Kwong Tip,. Sludge Ash as Lightweight Concrete Material. Journal of Environmental Engineering, American Society of Engineers. Vol.115, No 1, (1989), Pp 56-64. Government of the Federal Republic of Nigeria. General Specification (Roads and Bridges) Volume II. Revised 1997. Knapton J. “The Structural Design of Heavy Duty Pavement”. Fourth International Congress on Structural Engineering Analysis & Modeling (SEAM 4), Vol. II, (1997) pp 1-17.

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2nd International Conference On Engineering Research & Development: 1075 Innovations (15th – 17th April 2008), Benin City, Nigeria ICERD 08147: IMPROVINING THE PROPERTIES OF CONCRETE USING CHEMICAL ADMIXTURES IN THE WARM HUMID CLIMATE P.A. Okereke1, Ph. D; Dipl-Ing. Mnice; O.O. Odim2 Department of Building, 2 Department of Architecture, Imo State University P.M.B 2000 OWERRI,NIGERIA Abstract In using admixtures, the appropriate dosage and the choice of aggregate type in practice are usually based on mere prescription of the manufacturers rather than on empirical dat established under local condition. This paper examines the effect of super-plasticizing admixture and coarse aggregate type on the properties of both the fresh and the hardened concret in the warm humid climate with the objectives of achieving economy of cement and improving the quality of the concrete for any given type of coarse aggregate. Results were obtained from designed experiments using the Box-Wilson symmetric Plan-Bm for three independent variables: X1 (cement content), X2 (water-cement ratio) and X3 (plasticizing admixture). For easy analysis and interpretation of the results, multiple regression models of the second-degree polynomials were evolved. Results from the analysis of the experimental data show that the basic properties of concrete are considerably enhanced with the use of admixtures. This also helps to improve considerably the technology of concreting, thereby obviating some of the adverse effects of the tropical climate in concrete technology.

Introduction In most areas of Nigeria, two types of coarse aggregates are readily available - the naturally occurring gravel popularly known as “up-land” and chippings from granite rock. On the average, there seem to be preference by most engineers to the use of chippings rather than up-land gravel especially for jobs of major importance. Surprisingly, there is hardly any serious justification other than that chippings are usually free from organic impurities and silt as it is usually the case with up-land gravel. Although the abrasive strength of granite chippings is higher than that of naturally occurring gravel or ballast, that does not mean that it will produce a better concrete, all things being equal. [1,2] Silt and other impurities in gavel can be reduced to acceptable minimum as required by NIS 14:1978 simply by washing [3, 4] Characteristically, chippings are supplied in mono-particle sizes while up-land gravels are excavated from pits and contain different particle sizes ranging from the minimum to the largest acceptable ranges. How well the various particle sizes are distributed within the ranges determines the level of grading of the gravel. This too is a major factor in the amount of water required to produce the recommended consistency [5]. To be able to produce concrete with the expected strength however, will require an adjustment in the quantity of cement in the mix. To what extent the cement content is increased in order to obtain concrete with the desired properties should be of great concern to every engineer before taking a decision on which type of aggregate to specify for any given job. 2. Method of experiment and Analysis of results Two different types of experiments were carried out namely: i) Standard tests to establish some basic properties of the aggregates (sieve analysis and organic impurity tests); ii) Tests on some of the basic properties of concrete prepared from the two types of coarse aggregate (slump, strength, and density). pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1076 Innovations (15th – 17th April 2008), Benin City, Nigeria In the later case, tests were carried out by method of designed experiment using Box-Wilson Symmetric Plan- Bm [7] to obtain multiple regression models of complete polynomial of second degree: Y= bo+biXi+biiXi2+bij Xi Xj ----------------- (i) The critical values of the respective regression coefficients were determined and insignificant ones eliminated to obtain adequate models for the respective properties of the test samples..The granite chipping consists of 19mm single size particles. The aggregate content in each experiment was kept constant, while those of cement and water were varied in accordance with the coded values in the experimental plan as shown in Tables 1-2. Another variable factor introduced in the experiment is a chemical admixture of waterreducing plasticizer “CORMIX 6”. In view of its potential application in tropical climate [8,9,10,13] an investigation of its effect on the two types of aggregates was considered necessary. A total of 15 sets of experiments were carried out randomly in accordance with the experimental design; each set consisted of obtaining 3 measurements for each parameter. The average of the 3 obtained measurements was accepted as the test result for each set. 3. Regression Analysis From the results of the experiment as shown in Tables 2-5, multiple regression models for the consistency of concrete made with the two types of coarse aggregates were obtained after carrying out regression analyses of the models for their adequacy. The results of the regression analyses yielded the following models (Eqs.27): 3.1 Consistency of Concrete a) Up-land gravel Sg=10+37X1+35X2+3X3+18X12+22.8X22 + +19X33+38X1X2+2X1X3+1X2X3;

--------------(2)

b) Granite Chippings (dmax = 19mm) Sc= 17.19+23 X1+16X2+2X3+22X21+4X22- 10X23+-15 X1X2-4X1X3-2X2X3-------------(3) 3.2 Strength of Concrete ( Ri) in MPa: a) “Up-land” gravel Rg (1) = 5.85+0.87X1+2.93X2, -1.41X3 -1.84X12 X+1.93x22-2.41x32 0.69x1x2+1.6x1x3+1.8x2x3-------------- (4) Rg (7) = 22.64+0.24X1+ 1.59X2+1.44X3 -8.56X1+1.65x22- 7.62x32 +0.39x1x2+0.67x1x3+1.78x1x3 ------(5) Rg (28) = 32.54+1.33x3+-12.19x12 - 7.3x32 +2.75x1X2 +1.06x2x3 --------------

(6)

b) Granite Chippings Rc (1) = 1.5-0.35x1+1.55x2+2.46x3 - 1.3x12+X 1.91x22 +1.84x23 -1.08x1x2+3.38x1x3 ----- (7) pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1077 Innovations (15th – 17th April 2008), Benin City, Nigeria Rc(7) = 18.71-0.33x1+x1+3.15x2-4.41x5.55x12 +3.45x22 -8.16x32 0.21x1x2+6.54x1x3+0.8x2x3 ---------- (8) Rc (28) = 28.37-2.08x1+3.26x2- 4.10x3-8.9512 -2.5522 --3.4532 + 3.38 x1x3 ----------- (9) 3.3Bulk density ( ) in kg/m3 at 28 days old a) Up-land gravel g(28)=1881+87x2+36x3-520x12+x12-335x22+1751x23 -35x1+x2+-9x1x3+78x2x3 ---------------- (10)

-

b) Granite Chippings c (28) =2396-15x1+65x2-19x3-169x21 +17x22+ +77x23- 573x1+x2+13x1x3+36x2x3

----------- (11)

In the above formulae, X1, X2, and X3 are the coded values of the independent variables, respectively for cement, water-cement ratio and admixtures. 4. Factorial Analysis In order to highlight the individual and interactive effects which the various variable factors X1, X2, and X2 has on the measured parameters (consistency, strength and density of concrete) quasi mono-factorial analyses were made for each factor. In Figs.1-3 are shown graphically the results of the factorial analyses of the models using the relationship: Yi = Y{X}-bo = (bi+biXj)Xi +biiXii2 ------ (12) 4.1 Effect of Aggregate type on the Workability of Concrete In Fig. 1 is shown the mono-factorial analysis of the effect of the independent variables X1, X1 and X3 on the consistency of concrete prepared with the two types of coarse aggregates, while in Fig. 3 is shown the diagram of maximum effect of the factors. From the factorial analysis of the models the following inferences could be drawn on the effect of the factors on the consistency of concrete made from up-land gravel and granite chippings: i) Concrete prepared from gravel is more sensitive to factor X1 (water-cement) ratio than that from chippings. The factor X1 (water-cement ratio) impacts positively and sharply too on the consistency of concrete for both types of aggregates but its effect is greater in concrete made with gravel especially when X2 (cement) and X3 (Admixture) are at their highest levels of treatment. The same is true of X2. The effect of factor X3 (plasticizing admixture) on the consistency of concrete is not as pronounced as that of X1 and X2 but it is quite significant. Its effect is more pronounced with concrete made from gravel than that from chippings particularly at the maximum levels of X1 and X2, i.e., when the water-cement ratio is 0.8 and cement content is 300kg/m3 of concrete. 4.2 Effect of Aggregate Type on the Strength of Concrete The mathematical models for the 1,7 and 28-day strengths of concrete made from both types of aggregates are given in Eqs. (4-9), while the results of the mono-factorial analysis of the pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1078 Innovations (15th – 17th April 2008), Benin City, Nigeria factors X1,X2,andX3 on the strength development of concrete made from gravel and chipping are shown in figs 2-6 for the 1,7 and 28 – day cube strength. In all the diagrams for the mono-factorial effects, those of x2-cement content is most outstanding, yielding maximum values in the strength of concrete made with the two aggregate types. This goes to confirm that cement is the most determinant factor in the strength of concrete at all ages. The strength of concrete is highest when all the factors assume their average value of treatment, that is X1(0),X2(0)and X3(0).for concrete made from both types of aggregate. A summary of the differences in the 28-day strength of concrete for the two types of coarse aggregate is illustrated graphically in fig6-which shows strength characteristics for concrete made with gravel and chipping. This diagram clearly shows that gravel produces concrete of higher strength than chippings. This could be explained by the compact nature of the concrete due to the presence of insufficient quantity of the various particle sizes within the allowable sizes dmin< di < dmax . Thus, the more graded the aggregate, the less the voids ratio and hence the more compact and homogenous the mix. 4.3 Effect of Aggregate type on The Density of Concrete Eqs.(10 and 11) are the mathematical models of the density(unit weight)of concrete made from the two types of aggregates under study at ages 1,7,28 days. A comparison of the diagrams of effect of the three independent variablesX1, X2, and X3 on the density of concrete prepared with gravel and chippings (Figs. 1-3) could reveal the following: i) Of all the factors, X2 (cement content) has the greatest affect on the unit weight of concrete, regardless of the type of aggregate used. The effect of the other factors is however varied depending on the aggregate type. ii) Gravel aggregates yield maximum density when water-cement ratio and cement content are at their maximum levels of 0.8 and 300 kg/m3 respectively, but without admixture, it is at its least level. On the other hand, chippings yield maximum density when cement and admixture contents are at their highest levels but with the water-cement ratio at its minimum level, i.e., 4. Summary of Findings Results from the study show that the only advantage which chippings enjoy over naturally occurring gravel is being clean, without any need for washing. In terms of other parameters such as the rheological properties of the concrete (workability, etc.), naturally occurring gravel has an edge over chippings. Thus, by inference, economy of cement can be achieved through the use of gravel to obtain the specified concrete consistency with a given dosage of chemical admixture. Of greatest interest, are the strength characteristics of concrete prepared from both types of coarse aggregates. Findings from the study reveal that, given the same cement content, concrete produced from naturally occurring gravels results in higher strengths at all ages, and are by far more denser than that from chippings.

Conclusion and Recommendations Apart from being clean and free from organic impurities, chippings, especially mono-fractional particles have no comparative advantage over naturally occurring gravels. The latter is more cost effective in terms of cement and admixture contents in order to produce concrete of specified strength and density. Further studies on the effect of aggregate type on concrete are recommended to verify the durability, hardness and other mechanical properties of concrete produced from both types if the findings from this study are to be conclusive.

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2nd International Conference On Engineering Research & Development: 1079 Innovations (15th – 17th April 2008), Benin City, Nigeria

o

30 25 20

o o

15

………….. Chipping 10

__________ Upland

5

Table 3: PLAN OF EXPERIMENT- B3 AND RESULT ON THE SLUMP OF CONCRETE Levels of Treatme Variable factors nt and Test No. Results X1 (W) X2(C) X3(A) Xi max = 0.8 30 (+) 0.4 0 0.4 Chipp. Upland Xi min = 0.6 20 (-) 0 0.0 Xi av = 0 25 0 0.2 1 0 0 2 + 30 20 3 + 25 8 4 + + 175 80 5 + 38 7 6 + + 38 17 7 + + 30 17 8 + + + 175 76 9 0 0 3 5 10 + 0 0 65 65 11 0 0 12 0 12 0 + 0 65 47 13 0 0 25 6 14 0 0 + 30 8 15 0 0 0 10 12

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2nd International Conference On Engineering Research & Development: 1080 Innovations (15th – 17th April 2008), Benin City, Nigeria Table 4: RESEULTS ON 28-DAY CUBE STRENGTH Levels of Treatment and Test No.

Variable factors Results

Xi max = (+) Xi min = () Xi av = 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

X1 (W) X2(C) X3(A) (Mpa) 0.8 30 0.4 0 0.4 Chipp. Upland 0.6 20 0 0.0 25 0 0.2 19.7 + 8.8 + 26.2 + + 15.3 + 4.8 + + 7.4 + + 17.3 + + + 13.9 0 0 21.5 + 0 0 17.3 0 0 22.6 0 + 0 29.1 0 0 29.0 0 0 + 21.0 0 0 0 28.4

15.5 10.3 7.9 13.4 6.0 12.7 12.7 18.2 20.4 20.3 32.5 22.2 23.9 26.5 32.5

Table 5: RESULTS ON BULK DENSITY AT 28-DAYS

References [1] ACI Standard Recommended Practice in Hot weather concreting of ACI, Vol. 30 No.5 (1958). [2] L.A. Ajayi , (1990) . Production Of Quality Concrete In Nigeria” – Construction In Nigeria, Lagos. [3] T. Ridly. Hot Weather Concrete Problem – Journal ACI Vol. 28 No. 11(1957) [4] J. Hughes, T. Ridly (1962). Concrete Strength In West Africa” Note No. 12, WABRI, Accra , Ghana. [5] P.Kieger, (1959). Effects Of Mixing And Curing Temperature On Concrete Strength . Journal of ACI Vol. 29:No. [6] S.A.Mironov, et al (1960). RILEM Symposium On Hot Weather Concreting, Haifa Israel. [7] V.A.Voznesensky et al (1984).Methological Guides on the application MTE, HIACE Sofia, Bulgaria. [8] P.A.Okereke, (1987). Improving The Technology Of Concrete Works In Nigeria Using Chemical Admixtures. Ph.D. Dissertation submitted to the Specialized Commission on Construction Technology and Management of the Bulgarian Academy of Sciences, Sofia, Bulgaria. [9] P.A.: Okereke, (1991). Towards Optimal Concrete Mix Design For Tropical Climate. International Journal For Housing Science, Vol. 15 No. 4: [10] P. A. Okereke: (2003). Construction Materials: Testing and Quality Control in Tropical Climate Crown Publishers, Owerri. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1081 Innovations (15th – 17th April 2008), Benin City, Nigeria [11]Proceedings, Institute of Civil Engineers, Vol. 15, London (1960). [12] Proceedings, XI National Conference On Materials Testing And Control, NBRRI Lagos (1985). [13] P.A: Okereke,.(2006).Sustainable Use of Materials and Equipment for Construction Processes..Proc. 36th NIOB Annual Conference, pp. 13-

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2nd International Conference On Engineering Research & Development: 1082 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08187) The Quality of Concrete made with Typical Benin City Silty Sand. O.E Alutu FNIStructE(1)a). and E. N. Ejike, FNIStruct(2) Civil Engineering Department University of Benin, Benin City; (a)Phone No: 08055860042; (a) E-Mail: [email protected]

(1,2)

The purpose of this study is to carry out tests on concrete made with a typical Benin City silty sand and determine the major concrete quality indicators such as pulse velocity, water/cement ratio and compressive strength in order to justify the continued utilization of such sands in concrete production in and around Benin City. To do this, concrete made with the selected sand were designed using DOE mix design method and test cubes were cast in three batches. Two cubes were cast for each of the sixteen consecutive tests carried out and averages taken for each design grade strength of 10,20,30,40 and 50N/mm2. Also, pulse velocity and rebound hammer tests were carried out on the cubes before testing the cubes destructively. The results show that concrete produced with the Benin City silty sands are of good quality in all respect but generally characterized by low 28th day – characteristic strength. The sands should therefore be used in construction provided that the mean strength aimed at during design is sufficiently higher than the characteristic strength from structural point of view to enable every part of the structure have adequate strength. Key words: Sand, Utilization concrete, quality.

[ For the detailed document go to page 1585]

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2nd International Conference On Engineering Research & Development: 1083 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08188) The Influence of Vibration Time and Sand Type on the Compressive Strength of Sandcrete Hollow Blocks. O.E Alutu ENIStructE(1). and A. Omorogie(2) Civil Engineering Department University of Benin, Benin City; (a)Phone No: 08055860042; (a) E-Mail: [email protected]

(1,2)

The purpose of this study is to see if varying the vibration time and sand type during moulding of blocks would affect the strength of the blocks. To this end, seven types of sands: Okuahia and Ovia river sands; Okuahia, Ovia, Ikpoba flood and Okhoro erosion sands were collected for the study. A total of 315 blocks each in 150mm and 225mm sizes with cement to sand ratios of 1:6 were made using the seven brands of sand. The blocks were vibrated for 10, 15, 20, 25, and 30 seconds and tested for compressive strength at 7 days, 14 days and 28 days respectively. The result showed that the relationship between compressive strength of the blocks and the vibration time for various sand types was linear up to vibration time of 30 secs. The sand type also influenced the strength of the blocks as Okuahia river sand gave the highest compressive strength followed by Ovia river sand and the least was Okhoro erosion sand. At least 52% increase in compressive strength of 150mm and 225mm sandcrete blocks were achieved by raising the vibration time from 15 seconds to 25 seconds in the seven types of sand and 100% increase is achieved by raising the vibration time from 15 to 30 seconds.

[ For the detailed document go to page 1577]

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2nd International Conference On Engineering Research & Development: 1084 Innovations (15th – 17th April 2008), Benin City, Nigeria

ICERD 08219: THE EFFECTS OF ADDITIVES OF CEMENT AND SILICA CLAY ON THE THERMOPHYSICAL PROPERTIES OF SAWDUST

I.O. Ogunleye Department of Mechanical Engineering, University of Ado Ekiti, Ado-Ekiti, Nigeria [email protected] and 08067430191

ABSTRACT The thermo-physical properties of some varieties of sawdust and some additives are presented. They are thermal conductivity, heat capacity and specific gravity. The methods of investigation used are Lee’s Disc Apparatus, heat balance and gravimetric method respectively. The sawdust specimens were obtained from six varieties of wood. The additives employed on two typical sawdust samples are cement and silica clay. The values of thermal conductivity range between 0.440 - 0.204 W/m K, and heat capacity between 58,644.08 - 29,584 J/kg K . The highest specific gravity is 0.256 and the least value is 0.107. It was observed that as the clay content increases, specific gravity and the thermal conductivity also increases while the specific heat capacity decreases KEYWORDS: Sawdust, Additives, Cement, Clay, Thermo-physical, Properties 1

INTRODUCTION Sawdust is a small discontinuous chips or small fragments of wood produced during sawing of logs of timber into marketable sizes. They are fine particles of wood obtained by cutting the wood with a saw. It is an agricultural waste product that has a variety of practical uses like in making particle board, as solid fuel, packaging filler etc [1-3]. Usually, some additives or hardener are added to sawdust to improve the particles board properties depending on what they are to be used for [1, 4] . According to Patura [4], particle boards have a wide variety of applications such as ceilings and doors, TV cabinet, suitcases, Table top, trays, acoustic tiles for furniture, and exterior sheathing boards. The use of a mixture of sawdust, sand and cement for making wall panels has been fairly common in parts of Northern NSW for many years. The history of this technology goes back to at least the 1930's, and it has been researched and applied in parts of the USA, UK and Germany. In some instances, the materials (with various adaptations) have been used for flooring as well as walling [5] Adeyemi et al [6] investigated the effects of additives on sawdust cement boards. Particle boards were produced from locally available raw materials such as sawdust, as the main material, cement, as a binder and varying percentage of silica sand and laterite clays, as additives. Air-cured sawdust cement boards were tested for physical properties such as density, percentage of water absorption, percentage of shrinkage and percentage of warpage and mechanical properties; compressive strength and modulus of rupture. Higher percentage additions of silica sand and laterite clay give higher values of density, modulus of rupture and compress we strength but with lower percentage water absorption Sawdust types depend on the variety of wood from which they are obtained. Sawdust from various wood types look alike but their thermo-physical properties differs from one another. Ogunleye and Awogbemi [7] investigated the thermo-physical properties of eight varieties of sawdust and found them to be with different numerical values. This work investigates thermo-physical properties of varieties of sawdust with additives of silica clay and cement as binder. The thermo-physical properties investigated are thermal conductivity, loose particle density and specific heat capacity. The sawdust samples were obtained from varieties of woods with botanical and local names given as follows: albizia zygia (Ayere), milicia excelsa (Iroko),entandrophragma candollel (Ijebo), ceiba pentandra (Araba), terminatia superba (Afara), antiaris toxicaria(Oriro) pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1085 Innovations (15th – 17th April 2008), Benin City, Nigeria

2.

Methodology or Experimental

Sawdust specimens’ collection The sawdust specimens were collected during milling operations of the wood varieities named above from Bashiri Sawmill, Ado-Ekiti. This helps to avoid sawdust samples that are mixture of varieties of wood. The sawdust samples were sun dried, grounded and sieves before usage. The mixtures of sawdust, silica clay and cement were prepared in different proportions. The two typical sawdust varieties from “Iroko” and “Araba” types of woods are investigated. In all there are six samples of pure sawdust from six different types of woods and six samples of sawdust with additives in the proportion reported by Adeyemi et al, (2006) and shown in Table 1

Table 1: Proportions of Sawdust Additives Samples Sample name Wood type % of sawdust % silica clay content content A Araba 85 0 B Araba 75 10 C Araba 65 20 D Iroko 85 0 E Iroko 75 10 F Iroko 65 20

% of cement content 15 15 15 15 15 15

Determination of Thermal conductivity using Lee’s Disc Apparatus The experimental set-up shown in Figure 1 consisted of a steam flask connected to a steam chest, S. The base of the steam chest was placed over a poor conducting disc B, which in turn was placed on top of a suspended brass disc C. The suspension was done with two strings in a place away from draught. A little glycerine was used to ensure a good thermal contact. Two thermometers were inserted into the two holes, one on disc A and the other on disc C. As the steam flow through S, the two thermometers were read at every five minute, until they indicated that a steady state has been reached. The steam chest S was removed, while disc C was heated with a low bunsen flame until its temperature was about 10oC above the previous steady temperature reached. The bunsen burner was removed and the disc C, containing sawdust particles of known mass m was allowed to cool. The cooling rate of disc C was recorded at every minute until its temperature fell to about 20oC below the initial steady temperature. The cooling rate curve i.e. cooling rate versus time curve was plotted and the slope of the tangent (g) to the curve at the temperature corresponding to the steady value was measured. This experimental method was repeated for all the sawdust specimens. Rearranging Fourier’s Law according to Oladebeye and Oladebeye [8], the thermal conductivity Ks of sawdust is given as 4mcgX kg = ---------------(1)  d2 (T1-T2) where m = mass of brass disc C; c = specific heat capacity of brass disc C, d = internal diameter of disc B; X= thickness of disc B, T1 and T2 = temperatures of the two faces of disc B. Cp of brass is 380 J/kgK [9]. The internal diameter d of disc B is 0.068m and its thickness X is 0.00322m .

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2nd International Conference On Engineering Research & Development: 1086 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 1: Lee’s Disc Apparatus Determination of specific heat capacity Figure 2 shows the experimental set for the determination of specific heat capacity which consists of heating element (coil), a thermometer, wires, ammeter, voltmeter, calorimeter, fiberglass, multimeter, plastic cup, stop watch, battery and an inverter ( to charge the battery), 0.156 kg of water and 0.319 kg of sawdust specimen. 0.156 kg of water inside a calorimeter was heated with an electric heating coil. The calorimeter was insulated with fibre glass around its circumference and then inserted into a plastic cup which already has a 0.319 kg of sawdust sample in it such that the calorimeter made direct contact with the sawdust. The flow of current in the circuit was measured with an ammeter, voltage drop across the heating coil was measured with a voltmeter, and the rise in temperature of the heated water with time was measured with a laboratory mercury thermometer. A K-type thermocouple buried inside the sawdust particles through a pinhole at the bottom of the plastic cup was used to monitor the increase in temperatures of the sawdust samples with time. This procedure was repeated for the sawdust specimens and all the readings taken recorded. The specific heat capacity (Cp) was estimated from a heat balance equation expressed as IVt = mwCw ÄTw + mcCcÄTc + msCsÄTs + QL (2) where I = current, v = Voltage, t = Time, mw = mass of water , Cw = specific heat capacity of water ÄTw = change in temperature of water, mc = mass of Calorimeter, Cc = Specific heat capacity of Calorimeter, ÄTc = Change in temperature of Calorimeter, ms = mass of sawdust specimen Cs = Specific heat capacity of sawdust specimen to be determined, ÄTs = change in temperature of sawdust specimen, QL = Heat loss, assumed to be negligible

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2nd International Conference On Engineering Research & Development: 1087 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 2: Experimental set-up for determining heat capacity of sawdust From equation (2), making Cs the subject, we have IVt – (mwCwÄTw + mcCcÄTc) Cs =

(3) msÄTs

Packed Loose Particle Specific Gravity A graduated measuring cylinder with a maximum volume of 100 cm3 which weighs 0.554 kg was employed for this investigation. With the aid of a sensitive digital balance, the mass of sawdust at various volumes determined with a measuring cylinder, which ranged from 10 to 100 cm3 were obtained and recorded. The digital balance used has 0 – 1 kg range with a sensitivity of 0.5g. The mass of equivalent volumes of water in the graduated measuring cylinder were determined also with the same digital balance. The plot of masses of sawdust versus the masses of water at an equivalent volume range of 10 to 100cm3 was carried out. The slope of each straight line obtained for different sawdust varieties is the loose particle specific gravity of the sawdust samples, S. The loose particle density of sawdust is given as SS = Sw (4) where SS = Loose particle density of sawdust specimen , S = Specific gravity of sawdust specimen and w = Density of water 3.

Results and Discussion

The steady temperatures, T1 and T2 of disc A and C respectively for all the 12 samples investigated with the Lee’s Disc Apparatus are shown in Table 2. The cooling rate curve for all the samples are shown in Figure 3. The mass m of disc C, the internal diameter d of disc B and its thickness X by measurement are 1.015kg, 0.068m and 0.00322m respectively. According to Holman [9], the specific heat capacity Cp of brass is 380 J/kgK pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1088 Innovations (15th – 17th April 2008), Benin City, Nigeria Table 2: Steady Temperatures of disc A and C and the slope of the cooling curves. T1 (oC) T2 ( oC) Samples of sawdust and g (oC/s) their additives Araba 98 66 -0.0191 Iroko 80 38.1 -0.0539 Oriro 89 42 -0.0594 Ayere 97 71.8 -0.0182 Afara 94 50.3 -0.0463 Ijebo 97.1 64.7 -0.0378 A 96 64 -0.0131 B 95 59 -0.0151 C 94 66.5 -0.0163 D 96.05 61.05 -0.0126 E 95.1 64 -0.0169 F 94 66.05 -0.0183

80

70

T e m p e ra tu re in d e g r e e C e ls iu s

60

50

40

ARABA IROKO ORIRO AYERE AFARA IJEBO A

30

20

B C D E F

10

0 0

100

200

300

400

500

600

Cooling Time (sec)

Figure 3: Cooling rate of sawdust and sawdust with additives samples Using these data in equation (1) we have 341.84g Kg = ---------------(T1-T2)

(5)

From Figure 3, the slopes of the cooling rate curves were obtained and shown in Table 3 along with the thermal conductivities of the sample as estimated from equation (5) above. A typical example is that of Araba with g = 0.0191oC/s and (T1-T2) = 32oC, therefore the thermal conductivity for Araba is Kg =

341.84 (0.0191) --------------------- = 0.204 W/m oC (98-66)

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2nd International Conference On Engineering Research & Development: 1089 Innovations (15th – 17th April 2008), Benin City, Nigeria Table 3: Thermal conductivity of sawdust and sawdust with additives g (oC/s) Samples of sawdust and Kg W/m oC their additives Araba 0.204 0.0191 Iroko 0.0539 0.440 Oriro 0.0594 0.432 Ayere 0.0182 0.247 Afara 0.0463 0.362 Ijebo 0.0378 0.399 A 0.0131 0.140 B 0.0151 0.143 C 0.0163 0.203 D 0.0126 0.123 E 0.0169 0.186 F 0.0183 0.224 From equation (2) the only unknown variable is the heat capacity of sawdust, Cs. The values of constant variables by direct measurement and from standard Tables of Engineering Data are: mw = Mass of water is 0.138kg. ms = Mass of sawdust is 0.0309kg. mc = Mass of calorimeter is 0.0905kg. Cc = Specific heat capacity of calorimeter is 383.1 J/ kg K Cw = Specific heat capacity of Water is 4187 J/kg K The experimental data for all the samples are shown in columns 2-5 of Table 4 Table 4: Experimental data with estimate of specific heat capacity Sample Ave Averag Chang ÄTw ÄTs specific s of I e e in heat (oC (oC capacit sawdust voltage time (A) ) ) and V t y their (V) (S) J/kg K additive s Araba 1.79 12.6 2100 42 12 58644 Iroko 1.74 13.75 1980 46 21 29584 Oriro 1.76 13.43 1920 45 14 41195 Ayere 1.78 12.42 2100 51 16 30723 Afara 1.66 14.33 1920 47 10 54647 Ijebo 1.74 13.59 1860 42 17 34758 A 2.18 8.36 3600 53 10 107275 B 2.65 7.93 3300 55 13 88776 C 2.74 7.74 3240 65 12 77944 D 1.87 8.13 3540 56 11 57429 E 1.66 8.08 3720 59 15 29652 F 1.69 7.81 3120 63 11 7633 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1090 Innovations (15th – 17th April 2008), Benin City, Nigeria IVt – (mwCwÄTw + mcCcÄTc) Cs =

(3) msÄTs On application of equation (3) on the data in Table 4, the estimated values of the specific heat capacity for the samples are shown in the last column of Table 4. The specific gravities of the sawdust samples and sawdust with additive samples are the slopes of the straight lines obtained from the plot of mass of sawdust samples verses the mass of equivalent volume of water as shown in Figure 4 for nine samples. The summary of the results for all the samples investigated re shown in Table 5 0.12

Mass of sawdust sample

0.1

Araba Iroko Oriro Ayere Afara Ijebo A B C

0.08

0.06

0.04

0.02

0 0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

Mass of water

Figure 4: The mass of sawdust and its additives samples versus the equivalent mass of water

Table 5: Summary of results Samples of Thermal sawdust and Conductivity their W/m oC additives Araba 0.204 Iroko 0.440 Oriro 0.432 Ayere 0.247 Afara 0.362 Ijebo 0.399 A 0.140 B 0.143 C 0.203 D 0.123 E 0.186 F 0.224

specific heat capacity J/kg K 58644.08 29584.8 41195.59 30723.41 54647.83 34758.54 107275.2 88776.8 77944.04 57429.5 29652.78 7633.261

Specific gravity

0.192 0.233 0.162 0.256 0.107 0.220 0.149 0.159 0.213 0.265 0.281 0.305

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2nd International Conference On Engineering Research & Development: 1091 Innovations (15th – 17th April 2008), Benin City, Nigeria From Table 5, sawdust from “Iroko” wood type has the highest thermal conductivity of 0.440 W/m K while sawdust from “Araba” wood has the lowest thermal conductivity of 0.204 W/m K. “Iroko” has the lowest specific heat capacity of 29,584 J/kg K and “Araba” has the highest value of specific heat capacity of 58,644.08 J/ kg K, “Ayere” has the highest specific gravity of 0.256 and “Afara” has least value of specific gravity of 0.107. As mentioned earlier on, the mixtures of iroko and araba sawdust with additives of silica clay in various ratios and fixed 15% cement content in all the samples were investigated. It was observed that as the clay content increases, specific gravity and the thermal conductivity also increases while the specific heat capacity decreases. Conclusions Sawdust often regarded as solid wastes can be converted to create wealth beneficiary to the society. The research work clearly shows that varieties of sawdust have different thermo-physical properties and can be utilized for different purposes. Sawdust from Araba and Iroko have the lowest and highest thermal conductivity and the highest and lowest heat capacity respectively. Sawdust from iroko wood is a poor material for thermal insulation but a good material for particle board with 20% clay content while sawdust Araba wood is a better insulation material and ceiling board Acknowledgements The author is grateful to the University of Ado Ekiti, Federal Polytechnic, Ado Ekiti and Mr Oyelakin Abel for support and assistance in the course of this research. REFERENCES 1 Akers, L.E. (1969), Particle Board and Hardboards, Monograph on Furniture and Timber, Pergamon Press Publisher 2 Williams Callister D. Jr (1997), Material science and engineering: an introduction 4th ed. John Wiley and Sons Inc , Canada, pp 646,776,793-796 3 Hagerty D.J. Pavoni L.J and Hear E.J. (1973). Solid waste management van Nostrand Reinhold, Newyork, U.S.A. 4 Patura, M.J. (1967), By products of the Cane Industry, An Introduction to their Industrial Utilization, Elsevier Publishing Co., London, UK 5 Information from: www.rainforestinfo.org.au 6 Adeyemi, S.O., Olarewaju, B.S. and Adeyemi, M.B., (2006), Effects of Additives on the Properties of Sawdust Cement Board, Nigerian Journal of Mechanical Engineering, vol 4, No 1, pp 41-53 7 Ogunleye, I.O. and Awogbemi, O. (2007), Dtetermination of thermo-physical properties of Eight Varieties of Sawdust, Journal of Research in Engineering, vol 4, No 4, pp 8-14 8 Oladebeye, D.H and Oladebeye, A.O (2006), Effect of Agricultural Waste on Thermal Conductivity of Natural Rubber Composite, Nigerian Journal of Mechanical Engineering, vol 4, No 1, pp 54-63 9 Holman J.P( 1981), Heat Transfer, Mcgraw-Hill International Book Company, London, pp 542

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2nd International Conference On Engineering Research & Development: 1092 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08220) Emerging construction technologies enables environmental protection: Rubberized concrete

G. Senthil Kumaran1 nurdin Mushile1 M.I. Laxmipathy2, 1Dept. of Civil Engineering & Environmental Technology KIST, BP 1900, Kigali, Rwanda 2 School of Civil Engineering, SRM University, Tamilnadu, India Email: [email protected].

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2nd International Conference On Engineering Research & Development: 1093 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08260) THE POTENTIAL USE OF PERIWINKLE SHELL AS COARSE AGGREGATE FOR CONCRETE

J.O Osarenmwinda* and A.O Awaro Department of Production Engineering, University of Benin, Benin City,Nigeria. *joosarenmwinda @yahoo.com +2348023718684

Abstract The potential of periwinkle shell as coarse aggregate for concrete was studied in this paper. The properties of concrete made with periwinkle shell as coarse aggregate were examined and compared. Test conducted on the concrete was compressive strength test. Prescribed mix design of 1:1:2, 1:2:3, 1:4:6, 1:2:4 and 1:3:5 were used to produce concrete cubes used for testing. The different constituent that make up the periwinkle concrete are present in the ratio as cement: sharp Sand: Periwinkle shell. Batching was done by volume and the corresponding weight recorded. The result shows that periwinkle shell has a bulk density of 517kg/m3 and specific gravity of 2.05. The cubes were tested at hydration period of 7, 14, 21 and 28days to determine the compressive strength of the periwinkle shell concrete. The results shows that design mix of 1:1:2, 1:2:3 and 1:2:4 with compressive strength of 25.67 N/mm2 ,19.50N/mm2 and 19.83N/mm2 at 28days hydration period respectively met the ASTM-77 recommended minimum strength of 17N/mm2 for structural light weight concrete while mix design of 1:4:6, and 1:3:5 with compressive strength of 14.00N/mm2 and 16.50N/mm2 respectively did not met the standard. Keywords:perwinkle shell,concrete,compressive strength,coarse aggregate INTRODUCTION Concrete is composite material consisting of fine and coarse aggregate combine into one cohesive form by a suitable medium such as cement paste [1]. Concrete is one of the major components of any building construction and its production cost will go a long way in affecting the overall cost of construction project. In Nigeria the cost of building material is high, this has led to projects being abandoned or quality of the construction compromised. The coarse aggregate used in concrete work could be natural in the form of crushed rocks like granite, basalt e.t.c or artificial (manufactured) by processing clay, shale, sintered pulverized Fly ash [2]. Due to escalating cost of construction especially in developing countries, different attempt have being made to substitute wholly or partly some of the constituent of concrete. Past research documents the incorporation of waste into concrete product as concrete aggregate, sand or cement mortar.Osarenmwinda and Uziewe utilise palm kernel shell as coarse aggregate for concrete production[3].Their study revealed that design mix of 1:11/2:3 and 1:2:3 gave strength of 23.33 N/mm2 and 17.2 N/mm2 respectively for 28 days hydration and met the ASTM-77minimum strength of 17 N/mm2 for structural lightweight concrete. Other researchers also utilised waste palm kernel shell for concrete [4-5]. Their results were satisfactory. Yoon et al. recognised that along the southern coast of Korea, large quantity of oyster shell was illegally dumped, adjacent to oyster sites[6]. They investigated the potential of this waste into useful construction materials. In their study, oyster shell was pulverised and combined with sand before being added to cement and water .the quantity of oyster were varied as different dosages (20%, 40%, 60%, and 80%) the compressive was found to decrease with increasing amount of oyster shell., with exception of 40% shell yielded an unexpected increase in compressive strength .Other study which have incorporated waste materials into concrete as new aggregates, include coconut shells [7], hazelnut shell and black tea waste [8],steel slag and limestone aggregate[9] and wood aggregates [10].Of these studies, black tea waste was found to have the least positive effect on concrete strength. The periwinkle shells belong to the seashells family. The periwinkle is a small greenish blue mane snails of the littonnae family which is widely distributed in the littoral drift sand banks of both the pacific and pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1094 Innovations (15th – 17th April 2008), Benin City, Nigeria Atlantic Oceans. In Nigeria it is found in large quantity in the Niger Delta region. Periwinkle shell have rough surface with open rounded end and tapered on the other end and lie as waste in riverine part of Nigeria. Since compressive strength is the most important factor when creating structural building materials [11], this study is to investigate the compressive strength of concrete produced from periwinkle shell when used as coarse aggregate. Methodology MATERIALS The materials used for concrete production were sharp sand from Okhuare River, in Benin City, Nigeria, Portland cement and water. TESTS The following tests were carried out to ascertain the suitability of uncrushed periwinkle shell as coarse aggregate for concrete. SIEVE ANALYSIS The experiment was carried out using 200g of sharp sand and periwinkle shell, using different sieve size ranging from of 3.35mm to 15mm for the coarse aggregate (periwinkle shell) and sieve size of 75um to 10mm for the fine aggregate (sharp sand). SPECIFIC GRAVITY TEST The apparent specific gravity was determined using the displacement method. Samples were taken from both the sharp sand palm kernel shell. The samples were immersed in distilled water for 24 hours after which they were air dried by exposing to cool air and then weighed. They were then dried in an oven until the surface moisture was evaporated and it was then reweighed. The specific gravity was calculated as follows: W1= Weight of bottle W2= weight of bottle + sample W3= weight of bottle + sample + water W4= weight of bottle + water W = weight of water displaced by sample Weight of water = W4 - W1 Weight of sample = W2- W1 Weight of water added to sample = W3 – W2 Weight of water displaced by sample, W = (W4 - W1) – (W3 – W2) Specific gravity of sample =

W2  W1 W

------------- (1)

BULK DENSITY TEST In determining the compact density a cylinder weight 1865g and measuring 11.5cm in depth and 10.0cm in diameter was used. The cylinder was filled in three stages, at 1/3, 2/3 and when filled up completely. At each stage the aggregate is tampered 25 times with a 16mm rod. The cylinder was then levelled with a straight edge, which it was over flowing and its content weighted. Bulk density was calculated as follows: Wee = Weight of empty cylinder Wec = Weight of cylinder + compacted sample Vc = Volume of cylinder Compacted bulk density = Wec – Wee ---------- ( 2) Vc pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1095 Innovations (15th – 17th April 2008), Benin City, Nigeria COMPRESSIVE STRENGTH TEST This test was carried out to determine the compressive strength of the Lightweight concrete specimen at different hydration period (7, 14, 21 and 28 days) for the different mix proportion, using the compressive testing machine. The specimens were casted using cast-iron mould measuring 100mm x 100mm x 100mm. Before the moulds were assembled, their matting surfaces were coated with engine oil and thin layer of engine was also applied to the inside of the mould. This was done to prevent the development of bond between the moulds and concrete specimen and compacted with a table vibrator after which the top surface was smoothened by a trowel. The cubes were then stored undisturbed for 24 hours at room temperature after which mould were removed and the cubes were cured in water at 24oC. At the specified hydration period the concrete cubes were tested using the compressive testing machine, 3 cubes per design mix. The cubes were place with the cast faces in contact with the platen of the testing machine i.e. the position of the cube when tested is at right angles to the platens. The load on the cube was applied at the rate of 15mm per minute. The load was increased until the cube fails and the strength when is fails was noted. Compressive strength was determined using equation

Compressive strength SC

Sc = Where P =

= crushing load Cross – sectional area of cube

P bL --------------- ( 4) failure load in KN; b = breath of cube in mm and L = length of cube in mm

MIX DESIGN PROCEDURE Light weight aggregate concrete was produced by using composite material composed of Portland cement, fine aggregate (sharp sand), coarse aggregate (Periwinkle shell) and water. The production of the concrete was done in batches using prescribed mix ratio of 1:1:2, 1:2:3, 1:4:6, 1:2:4 and 1:3:5. The different constituents that make up the Periwinkle shell concrete are present in the ratio as cement: sharp sand: Periwinkle shell. Batching was done by volume and corresponding weight of each concrete composition recoded. The design involved selecting concrete, with a goal to achieve a mix with good quality, proper workability for placement and economy. The Periwinkle shell was first washed to remove any trace dirt and dried. The sharp sand was then sieved using sieve with a size of size of 5.00mm according to BS 410. Batching was done by volume. After selecting the require mix ratio. The sand, Periwinkle shell and cement were measured into a pan and transferred into the mixer, after which water is added to mix the aggregate and provide workability. The concrete mix was then put inside the already prepared mould and place on the vibrator table, where it is vibrated to remove air void in the concrete mix and made dense. It is then levelled with a trowel and allowed to stand undisturbed for 24 hours before it is was cured in a water bath to the required hydration period. Results and Discussion The bulk density of the periwinkle shell and that of the fine aggregate (sand) were found to be 517Kglm3 and 1590 Kglm3 respectively using equation (1).. Table 2 and 3, shows the specific gravity of periwinkle shell was 2.05 and fine aggregate sand was 2.60 respectively. Table 4 shows the particle size distribution (sieve analysis) of the fine aggregate (sand) ranged from 15um to 3.35mm.

The result of the compressive strength of the periwinkle shell concrete for prescribed mix ratio of 1:1:2, 1:2:3, 1:4:6, 1:2:4 and 1:3:5. For 7, 14,21 and 28 days hydration period is shown in figs.1-5 respectively. It was observed the compressive strength increased as hydration days increased for all concrete mix tested. The compressive strength ranged from 14.00N/mm2 to 25.67N/mm2 for hydration period of 28days( fig 6). It was pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1096 Innovations (15th – 17th April 2008), Benin City, Nigeria observed that mix design 1:1:2 has the highest compressive strength of 25.67N/mm2 and mix design 1:4:6 has lowest compressive strength of 14.00 N/mm2 for hydration period of 28days. The results also shows that design mix of 1:1:2, 1:2:3 and 1:2:4 with compressive strength of 25.67 N/mm2 ,19.50N/mm2 and 19.83N/mm2 at 28days hydration period respectively met the ASTM-77 recommended minimum strength of 17 N/mm2 [12] for structural light weight concrete ,while mix design of 1:4:6, and 1:3:5 with compressive strength of 14.00N/mm2 and 16.50N/mm2 respectively did not met the standard. The density of different mix design is shown in fig.7 was observed to be within the range of 1979kglm3 and 2160 kglm3 This is within the density for lightweight concrete, which is 1750-2400Kg/mm3 [13]. It was also observed that mix design 1:3:5 has the minimum density of 2104kg/m3 and mix design 1:2:4 has the maximum density of 2160kglm3 for hydration period of 28days. Thus classifying the concrete made with periwinkle shell as lightweight.

CONCLUSION The potential of periwinkle shell as coarse aggregate in the construction of structural concrete has been investigated and found to be suitable. The results shows that design mix of 1:1:2, 1:2:3 and 1:2:4 with compressive strength of 25.67 N/mm2 ,19.50N/mm2 and 19.83N/mm2 at 28days hydration period respectively met the ASTM-77 recommended minimum strength of 17 N/mm2 for structural light weight concrete ,while mix design of 1:4:6, and 1:3:5 with compressive strength of 14.00N/mm2 and 16.50N/mm2 respectively did not met the standard. The result also shows that mix design 1:1:2 has the highest compressive strength of 25.67N/mm2. It is hoped that the use of Periwinkle shell as coarse aggregates for concrete production will greatly reduce the cost of building and construction in Nigeria.

REFERENCES 1.

A.M Neville(1981) properties of concrete. Low price Edition, English language book society and pitman.

2.

Kemps Engineering Year Book ( 1975) vol.2

3.

J.O Osarenmwinda and E.Uziewe(2003) “An Investigation into the Use of Palm Kernel Shell as light weight coarse aggregate for concrete.”Journal of Scientific and Industrial Studies vol.1No 1

4.

J .H Tay and K. Y Show(1996 )utilization of ashes from oil-palm wastes as a cement replacement material. Water and science Technology 34(11):185-192

5.

H .B Basri,M .A Mannan,M.F.M Zain,(1999).Concrete using waste oil palm shells as agregate.Cement and Concrete Research 29(4):619-922.

6.

G .L Yoon , B .T Kim, S H Han (2003).Chemical-mechanical characteristics of crushed oyster-shell. Waste management. Article in press

7.

R .R Almeida,C.H.S Menezzi,D .E Teixeiria.( 2002).Utilization of the coconut shell of babacu(Orbignya sp) to produce cement-bonded particleboard Bioresoure Technology 85(2):159163.

8.

A. Demirbus,A. Aslan (1998). Effects of ground hazelnut, wood and tea waste on the mechanical properties of cement. Cement and concrete Research 28(8):1101-104

9.

M. Maslehuddin,A.M Sharif,M. Shameem,M Ibrahim,M .S Barry (2003) Comparison of properties of steel slag and crushed limestone aggregate concretes. Construction and building materials 17(2):105-112

pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1097 Innovations (15th – 17th April 2008), Benin City, Nigeria 10.

K. Al Rim,.A Ledhem,O Douzane,R .M Dheilly,M Queneudec. (1999) Influence of the proportion of wood on thermal and mechanical performance of clay-cement-wood composites. Cement and concrete composites 21(4):269-276

11.

E yasar,Y. Erdogan, A kilic (2004). Effect of limestone aggregate type and water cement ratio on concrete strength. Materials letters 58(5):772-777

12.

American standards for test materials. Standard G330-77 “Specification for Lightweight Aggregate for Structure Concrete”.

13.

Guide for Structural lightweight aggregate concrete, ACI 213R, American Concrete Institute, Farmington Hills, MI,.

TABLE1: CONCRETE MIX DESIGN AND MASS OF COMPOSITION MIX 1:1:3 1:2:4 1:2:3 1:3:5 1:4:6

Cement

Sand

Periwinkle

Water

13kg 5.2kg 6.5kg 3.9kg 3.9kg

14.5kg 11.6kg 14.5kg 13.05kg 17.4kg

9.2kg 9.36kg 6.9kg 6.9kg 8.28kg

5 litres 3 litres 3.5 litres 3 litres 3.5 litres

TABLE 2:DETERMINATION OF THE SPECIFIC GRAVITY OF PERIWINKLE SHELL

Sample 1 2 3

W1

W2

W3

W4

W

175.18 195.54 178.31 Average

230.10 247.25 240.10

437.20 465.60 492.05

416.20 434.72 460.70

33.92 20.83 30.14

Specific Gravity 1.62 2.48 2.05 2.05

TABLE 3:DETERMINATION OF THE SPECIFIC GRAVITY OF SHARP SAND SAMPLE NUMBER Wt. Of bottle + water (full) W4 Wt. Of bottle + soil + water W3 Wt. Of bottle + sand W2 Wt. Of bottle W1 Wt. of water (W4 – W1) Wt of sand (W2 – W1) Wt of water displaced by sand W Specific gravity of sharp sand (W2 – W1)/W Temperature of test = 600C Average

1 67.48 94.72 55.00 11.08 56.4 39.72 16.68

2 68.17 92.85 51.89 11.38 56.79 40.96 15.83

2.63

2.56

2.60

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2nd International Conference On Engineering Research & Development: 1098 Innovations (15th – 17th April 2008), Benin City, Nigeria TABLE 4: SIEVE SIZES Mm 10 6.3 5 3.35 2.36 1.18 0.600 0.425 0.300 0.212 0.150 0.075

SIEVE ANALYSIS OF FINE AGGREGATE RETAINED IN g PASSING IN g

7.13 18.76 16.38 42.09 24.57 21.45 5.20 8.87

200.00 192.87 171.11 154.73 112.64 88.07 66.62 61.42 52.55

PASSING IN (%)

100.00 96.44 85.56 77.37 56.32 44.04 33.31 30.71 26.28

Fig. 1: compressive strength against number of days for mix design 1:1:2

FIG. 2: compressive strength against number of days for mix design 1:2:3

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2nd International Conference On Engineering Research & Development: 1099 Innovations (15th – 17th April 2008), Benin City, Nigeria

FIG. 3:graph of compressive strength against number of days for mix design 1:4:6

Fig. 4: compressive strength against number of days for mix design 1:2:4

fig. 5: compressive strength against number of days for mix design 1:3:5 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1100 Innovations (15th – 17th April 2008), Benin City, Nigeria

1:1:2

1:2:3

1:4:6

1:2:4

1:3:5

Fig.6: Compressive strength against mix design for 28 days hydration period

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Density

2nd International Conference On Engineering Research & Development: 1101 Innovations (15th – 17th April 2008), Benin City, Nigeria

1:1:2

1:2:3

1:4:6

1:2:4

1:3:5

Ratio

Fig. 7: graph of density against mix design for 28 days hydration period

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2nd International Conference On Engineering Research & Development: 1102 Innovations (15th – 17th April 2008), Benin City, Nigeria

TECHNICAL SESSION 7C: OIL AND GAS TECHNOLOGY I

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2nd International Conference On Engineering Research & Development: 1103 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08041) MAXIMIZING GENERATED ENERGY USAGE THROUGH COMBINED CYCLE COGENERATION

C.G. Enyi* and D. Appah Department of Petroleum and Gas Engineering University of Port Harcourt, P.M.B. 5323, Port Harcourt, Nigeria *Email: [email protected]

Abstract: Case studies from two Nigerian hydrocarbon processing industries, where gas turbine generators (GTG) were used for power generation were analysed. The first study analysed a simple cycle power generation where the GTG produced 25 MW of electricity and three separately fired boilers produced the required process steam. The second study analysed a combined cycle (cogeneration) where the same GTG that produced 25 MW of electricity also generated 90700 T/hr of steam from the turbine exhaust gas. The study shows that cogeneration (combined cycle) satisfied all the electric power and steam requirements of the plant. Simple cycle only satisfied the electric power requirement. Other disadvantages of simple cycle show that over 60% of the generated energy is lost to the environment in form of heat. A loss in production worth over $6,182,400 as a result of failure in a separately fired boiler was calculated. The study concludes that cogeneration must be undertaken with an awareness of energy system expansion, generation costs and the need for industrial energy of a given plant.

Key words: Energy, Power Plant, Cogeneration

INTRODUCTION The demand for energy continues to increase while the accessibility of natural resources to meet this demand continues to fall, as the easily recovered fuel deposits are depleted. It is expected that world energy demand will increase by 6% in 2020 [1]. The gap between rising demand and falling availability must be bridged by technology that improves the efficiency of extraction, conversion and use of energy. The combustion of fuel (gas) is the prime source of energy for the process industries and electric power generation [2]. Utility power generation characteristics and process energy requirements are essential parameters to establish the conditions to attain maximum plant cogeneration saving [2,3]. Cogeneration must be undertakes with an awareness of energy system expression, the constraints of available technology, utility system capacity, generation cost and the need for industrial energy in a given plant. The energy generations of two plants were analysed. The first plant produces electricity and steam for its process requirements using cogeneration (combined cycle), while the second plant produces electricity using sample cycle and also produces steam using package boilers. This paper discusses the benefits of combined cycle gas fired power plant as a means of maximizing energy generation in a process plant. It also recommends that future independent power plants owners should incorporate combined cycle as part of their energy generation strategy.

DESCRIPTION OF GAS FIRED POWER PLANT pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1104 Innovations (15th – 17th April 2008), Benin City, Nigeria (a)

Simple Cycle Power Generation In a simple cycle power generation, natural gas and compressed air are burnt in the combustion

section of a Gas Turbine Generator (GTG), the hat gaseous mixture is used to turn the rotor of an expander which is coupled to a stator and electrical power is generated as shown in Fig. 1. The exhaust gas escapes to the atmosphere at a temperature of 700F, studies carried out by researchers [4,5] in this area have shown that only 34% of the energy generated was used for electricity, 65% was wasted to atmosphere and 1% other losses.

Energy Balance for Simple Cycle Configuration

Simplified Simple Cycle Schematic TURBINE EXHAUST

65%

FUEL INLET AIR

COMBUSTOR

GT Exhaust

34% Electricity

GENERATOR COMPRESSORS EXPANDER

1% Other

Gas Turbine

Fig. 1: Simplified Simple Cycle

(b)

Combined Cycle Power Generation The combined cycle power plant uses the principle of simple cycle power plants. In addition, the process steam is generated by using the heat energy available in the exhaust gases that leaves the gas turbine, is shown in Fig. 2. The exhaust gas can be fired by the interval gas direct burner to bring the waste heat boiler (WHB) to full steam generating capacity. Simplified Combined Cycle (Back-End) Schematic

Energy Balance for Combined Cycle Configuration 20% Stack Gas

GAS TURBINE

EXHA UST

50% Electricity

HRSG STEAM GENERATOR

COOLING

CONDENSOR

2% Other

28% Cooling Water

Fig. 2: Simplified Simple Cycle

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2nd International Conference On Engineering Research & Development: 1105 Innovations (15th – 17th April 2008), Benin City, Nigeria The guillotine damper in the exhaust gas inlet duct can be closed to isolate the (WHB) from the gas turbine exhaust in case no steam is required in the system as shown in Fig. 3. About 78% of the energy generated was used as useful energy, 20% was wasted to atmosphere and 2% other losses [5].

CASE STUDY Two process plants situated in the southern part of Nigeria were considered in this analysis. The first plant has two process units: A and B and the utility plant. The plant energy requirements are supplied by four [4] simple cycle gas turbine generators (GTG), and three (3) separately fired package boilers (PKB) for steam production. Two (2) of the gas turbines and the three boilers are always in service at any given production stage. The GTGs and the three boilers generate an average of 25NW of electricity and 200,000kg/hr of medium pressure steam of 40kg/cm3 and 400C by using about 48,000m3/hr (33,000m3/hr for GTG and 15,000m3/hr for boilers), of natural gas unit A of the plant consumes about 190,000 kg/hr of the steam while the remaining 30,000 kg/hr of steam is exported to Unit B and utilities. In October, 2007, one of the boilers tripped out. Despite increase in load of the remaining two boilers, unit B was forced to shutdown due to shortage of steam production. The GTGs were running but produced only electricity since they are simple cycle power generators. The repair work on the boiler task 7 days to complete, and for unit B that produces about 450 tons of resins per day, this translated to a loss of 3220 tons of resins in 7 days, and financial loss of $6,182,400 at the current price of $1,920 per ton. Another plant situated in the same location has two GTG (one simple cycle and one combined cycle with waste heat boiler) and one package boiler. The plant consumes about 23,000m3/hr of natural gas in the GTG and its Heat Recovery Steam Generator (HRSG) supplementary firing to generate 25 MW of electricity and 90,700 kg/hr of medium pressure steam. In normal operation, most of the steam required to supply to the complex will be generated by the waste heat boiler (WHB). The package boiler will be operated in parallel with the WHB at turndown rates to make up the balance of the Mp steam requirements. The package boiler consumes additional 19,300 kg/hr of natural gas to produce 102,000 kg/hr. The plant operates at a high overall efficiency level in all anticipated operating modes including supplementary firing. The plant provides a flexible and economical configuration in meeting the cogeneration needs of the plant. Hence as far as the GTG is in service, there is continuous production of steam for the entire plant complex and there will be no anticipated unit shutdown due to steam outage, expect on power failure.

Table 1: Performances of Simple and Combined Cycles

(1) (2) (3) (4) (5) (6)

Fuel consumption (m3/hr) Power Generation (MW) Useful Energy Utilized (%) Energy loss to Vent (%) Steam Production (kg/hr) Production loss due to Boiler failure

Simple Cycle 33,000 25 34 65 0 Yes

Combined Cycle 23,000 25 78 20 90,700 No

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2nd International Conference On Engineering Research & Development: 1106 Innovations (15th – 17th April 2008), Benin City, Nigeria Table 1 shows the performance characteristics of the two cycles. It is clear, that cogeneration satisfied the overall energy needs of any process plant useful energy was about 78% compared to 34% for simple cycle, fuel consumption dropped to 23,000m3/hr and steam production was achieved at no extra fuel (or minimal) fuel gas. There will be no production loss due to boiler trip out since the source of steam production is the waste heat from the GTG. Finally, the environmental impact will reduce as most of the heat energies that would have been released to the atmosphere in the case of simple cycle, were used for steam generation.

CONCLUSION The cogeneration plant results in significant additional resource savings and emission reduction benefits compared with simple cycle to produce the same energy. The loss of $6,182,400 in a week would have been saved if the GTGs were combined cycle generators. Independent Power Plant (IPP) companies should incorporate combined cycle as part of their energy generation strategy. Finally the owners of the resin plant are considering modifications of both the power and steam generation systems. REFERENCES [1]

Hankina, M, “Energy Services for the World’s Poor” World Bank, Washington DC (2001).

[2]

Ahner, D.J., “Balancing the Industrial and Utility Energy Equation to Maximize Cogeneration Benefit”, Energy Technology Conference, March 1984, USA.

[3]

Energy Information Administration, “Energy in Africa”, 2000, Washington DC. http://www.eia-doe-gov/emeu/cabs/africa.ltml

[4]

World Bank, “Financing of the Energy sector in Developing Countries” Washington DC (1989).

[5]

Oke, C.A. “Gas Fired Power Plants Development in Nigeria: Status, Opportunities and Challenges”, Paper Presented at the workshop on Feb 2007, NNPC Towers, Abuja, Nigeria.

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2nd International Conference On Engineering Research & Development: 1107 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08045) ANALYSIS OF DECLINING INCOMES

A. A. Adeniji and K. I. Idigbe Non-renewable resources are such that their exploitations rate normally or ultimately will be at decline rate. Since the net rate of incomes from a discovered field proportional to the rate of production then a mathematical equation of one form is applicable to the other. We present equations that can be used to predict the life of a venture when the type of decline is identified. The decline types considered in this work belong to the family of hyperbolic decline equation. And for illustration purpose, graphs and charts relating parameters are presented.

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2nd International Conference On Engineering Research & Development: 1108 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08070) IMPROVING SEISMIC TECHNOLOGY IN THE SEDIMENTARY BASINS OF NIGERIA ENGR. KESS ASIKHIA1, EBINEDIA ITOHAN2 Department of Mechanical Engineering, Institute of Management and Technology, Usen, [email protected] 2 Department of Petroleum Engineering Institute of Management and Technology, Usen [email protected]

1

ABSTRACT

Petroleum exploration in Nigeria became intense after the discovery of the first commercial well in oloibiri (Niger Delta) in 1956. Of all the seven sedimentary basins in Nigeria, the Niger Delta basin had and is still receiving much attention because of its prolific potentials and as such has been grossly responsible for the progressive growth in the nation’s economy. The outcome of exploration activities in the other sedimentary basins have not been so encouraging because operators who were given concessions to operate on these basins relinquished their acreages with the conclusions that the zones were not potentials of oil and had no or little non-commercial quantities of gas. Results from the data acquired in some of these sedimentary basins with exception of the Niger Delta basins revealed that only 2D seismic had been employed during data acquisition while in the Niger Delta Basin, the 2D and 3D seismic had been employed so far. With the dynamic trend in seismic technology today where more sophisticated techniques like 3D and 4D seismic are available for proper delineation of subtle reservoirs, it would be improper or too early to draw conclusions on these sedimentary basins especially the northern basins. This paper intends to address the need to update seismic technology employed so far in exploring the nation’s sedimentary basins, as this would help the nation in achieving its desired target of 40 billions of crude by 2010. 1. INTRODUCTION After the discovery of the first oil well in 1956, much emphasis had really been placed on the Niger Delta basin. Of all the seven sedimentary basins in Nigeria, the Niger Delta basin has been solely and grossly responsible for the growth in the nation’s economy. In line with the fact that the nation needed to increase its oil reserve base, the Federal government gave concession to operators who were interested to explore and exploit some of these other sedimentary basins. The initial exploration effort among other things stimulated the interest of major oil companies with subsequent allocation of blocks to them under the production sharing contract (PSC) arrangement. However, some of these operators have relinquished their concession due to the fact that exploratory work carried by them so far have yielded little or no result. Reviewing the data acquired by some of these operators revealed that only the use of 2D had been employed so far during data acquisition. In the Niger Delta basin that is not the case as research reveals that improved techniques like the 3D seismic had been used and even 4D. With the dynamic trend in seismic technology where sophisticated techniques like the 3D and 4D seismic are available for proper imaging and delineation of subsurface reservoir structures, it would be improper or too early to draw conclusion on these other sedimentary basins especially the northern sedimentary basins. This paper intends to address the need to improve seismic technology employed so far in these sedimentary basins especially the ones that have shown indications of oil or gas

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2nd International Conference On Engineering Research & Development: 1109 Innovations (15th – 17th April 2008), Benin City, Nigeria 2. EXPLORATION ACTIVITIES IN THE DIFFERENT SEDIMENTARY BASINS OF NIGERIA The different sedimentary basins includes the following i. Bida or Nupe basin ii. Lullemmeden or Sokoto basin iii. Anambra basin iv. Benue Trough v. Chad or Bornu basin vi. Benin basin vii. Niger delta basin o

BIDA BASIN

GEOLOGICAL DESCRIPTION This basin extends from Kontagora in the north to beyond Lokoja in the southern part, a distance of about 400km.The basin merges with the Sokoto basin in the northwest. Its width is between 64km and 160km. The Bida basin is predominantly sandstone sequence and consists of coarse to fine grained sandstones, siltstones and claystones. Gravity and aeromagnetic evidence indicates that the sediment thickness in this basin ranges from 1000m to 3000m. SEISMIC ACTIVITIES IN THE BIDA BASIN Around the early 60’s and 70’s, (Nwaezeapu A.U., 2001) stated that GREAT BASIN PETROLEUM COMPANY had prospecting lease on this basin. They never shot seismic in the area though they identified a number of anticlinal features in a photogeological interpretation of the area. These features were not tested before Great Basins relinquished the acreage. They concluded that the basin had a low rating as a potential hydrocarbon province based on structural and surface evidence. However, if structures are present in depth and if coals are present beneath the topmost cover in the Bida basin, then there maybe prospects for deep dry gas there. o

LULLEMMEDEN OR SOKOTO BASIN

GEOLOGICAL DESCRIPTION This basin is situated on the North western Nigeria and beyond. The Nigerian sector of this lullemmeden is also called the sokoto basin. This basin is only slightly faulted and the beds dip regionally into the main part of the basin. Sediments deposited in this basin are about 1220m but thicken to about 1980m towards the north. SEISMIC ACTIVITIES IN THE SOKOTO BASIN (Nweazeapu A.U., 2001) stated that MOBIL started seismic work on this area when they were given concession to operate the area, they completed it after which they relinquished their concession for the following reasons: thinness of section, lack no well defined structures, paucity of clean reservoir sand. After Mobil left, ELF later carried some exploratory work in the basin but the initial evaluations were not encouraging and they had to abandon the area. o

ANAMBRA BASIN

(Yahaya M.,) stated that Anambra basin is a cretaceous/ tertiary basin is the structural link between the cretaceous Benue Trough and the tertiary Niger Delta basin, it is a sedimentary wedge bordered by the Abakaliki anticlinorium to the east, the basement rock and the Benue hinge line to the north and northwest respectively. Its petroleum hydrocarbon system encompasses source rocks, traps, seals and reservoir that are essential for a hydrocarbon accumulation to exist. The Anambra basin contains about 6000m thickness of shales and sandstones.

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2nd International Conference On Engineering Research & Development: 1110 Innovations (15th – 17th April 2008), Benin City, Nigeria SEISMIC ACTIVITIES IN THE ANAMBRA BASIN Initial exploration activities conducted by ELF PETROLEUM NIGERIA LIMITED in the basin found oil and mainly gas in the Anambra basin. The company however relinquished the concession and exploration activities terminated. o

BENUE TROUGH

GEOLOGICAL DESCRIPTION Benue Trough is in the north eastern part of the Niger. It is an intracratonic rift basin and has linkage with the Niger Delta. Its origin is associated with the African and south American plates during the late Jurassic/early cretaceous about 150million years ago. The Benue basin had early history of rifting and fluvial deltaic sedimentation leading to the deposition of thick sandstone sequence (Bima formation). Marine sedimentation during the cenomian – campanian deposited the shales and sandstones of the Yolde and the Pindiga formation in the upper Benue Trough. SEISMIC ACTIVITIES IN THE BENUE TROUGH (Nwaezeapu A.U., 2001) stated that around 1984 and 1989, seismic data acquisition was initially carried out by the NNPC and Petty Ray Geophysical Company. A total of 4,426km of regional 2D seismic data were acquired using dynamite as the energy source. This acquired data was use to evaluate the basin. The initial exploration effort among other things stimulated the interest of major oil companies there with subsequent allocation of blocks to them in 1993 under the production sharing contract (PSC) arrangement. After NNPC left, Chevron Petroleum Nigeria Limited (CPNL), Shell Nigeria Exploration Petroleum Company (SNEPCO) and ELF Petroleum Nigeria Limited were allocated blocks in this region. (Nwaezeapu A.U., 2001) also stated that Chevron drilled Nassara-1 well using 1650.91km of 2D seismic they acquired, their conclusion after drilling the well was that the well was dry but pre-drill expectations were high. SNEPCO acquired about 1504km of 2D seismic, which enable them to drill Kolmani river-1 well. Kolmani River-1 well encountered 87.5m of gross gas sand. Reserves of gas are sub economic (33bcf) and no oil was encountered in the well. ELF also were committed when they acquired 1484km of 2D seismic, which led to the drilling of Kuzari-1 well, which was latter found to be dry.

o

CHAD BASIN

GEOLOGICAL DESCRIPTION (Olugbemiro R. O.,) stated that The Chad basin is the largest intracratonic basin in Africa that spreads across the Niger, Chad and Sudan. It has one-tenth of its surface area in NE Nigeria. (Online Nigeria, 2008) stated that The Bima sandstone is the oldest sedimentary deposit in the Chad basin. A middle cretaceous shalelimestone succession subdivided into the Gongila at the base and Fika formation/shale at the top constitute the marine and transitional deposits which extend from the upper Benue trough into the southern Chad basin. The tertiary chad formation is very thick. EXPLORATION ACTIVITIES IN THE CHAD BASIN (Nwaezeapu A.U., 2001) stated that a total of 33, 643km of 2D seismic data were acquire in the Chad basin between 1977 and 1995. This made up of 13,376.09km of thumper of weight drop lines and the balance of 20,266.91km where dynamite was used as the energy source. Consequently, it was found that in all, 23 wells were drilled in the Chad basin and the total meterage penetrated was 75,054.5.This translates to an average depth of 3263.2km per well. Two (2) of these well:wadi-1 and kinasar-1 found gas in non-commercial quantities.

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2nd International Conference On Engineering Research & Development: 1111 Innovations (15th – 17th April 2008), Benin City, Nigeria

o

BENIN BASIN

This is also know as the Dahomey Employment .(DPR, 2003) stated that it has thickness of about 2500metres.(Olabode S.O.) also stated that It has a record of cretaceous and tertiary sedimentary rock unit. Some parts of this rock unit have been affected by basement induced fault systems, which are hither to active. EXPLORATION IN THE BENIN BASIN (DPR, 2003) also stated that “Yinko Falawiyo Nig-Ltd carried out 2D and 3D seismic”. From their assessment, it is believed that the Benin basin still has very good prospects. Oil and gas was found in commercial quantity approximately 156mmbls of crude oil and 1.5tcf of gas. The basin also has large tar (bitumen) sand deposit.

o

NIGER DELTA BASIN

GEOLOGICAL DESCRIPTION The Niger Delta basin located in the southern Nigeria is the largest along the West African coast. It is to date, the most prolific sedimentary basin in Nigeria by virtue of the impact size petroleum accumulations, discovered and produced. Classic integrated geological studies have shown that several different depobelts are abound in the Niger Delta basin, these depobelts are:      

Northern Greater Ughelli Central swamp Coastal swamp Shallow offshore

Onshore Niger Delta

Continental shelf Niger Delta Deep/ultra offshore Offshore Niger delta Deep/ultra deep waters

ONSHORE AND CONTINENTAL SHELF NIGER DELTA The onshore and continental shelf Niger delta are now mature terrains in term of petroleum exploration having being explored and produced for, more than half a century now. It has three characteristic geological formations namely:  



Akata formation: Which is composed of marine shales that forms the main source rocks for petroleum Agbada formation: This consists of the main reservoir unit and is made up of intercalation of sand and shale sequences. Most of the oil and gas so far discovered and produced to date in the Niger delta basin have been reservoired in this formation. Benin Formation: This is mainly composed of sand unit that has little petroleum bearing strata. EXPLORATION ACTIVITIES IN THE ONSHORE/CONTINENTAL SHELF NIGER DELTA BASIN

Exploration activities in these terrains initiated oil production in the onshore in 1958 and continental shelf in 1965 owing to huge petroleum potentials. (DPR, 2003) stated that 18, 200sqkm of 3D and 80, 500km of 2D pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1112 Innovations (15th – 17th April 2008), Benin City, Nigeria had been acquired on this basin by shell, Mabon, CNL, DPR AND TGS/NOPEC. Total number of wells is 4,493(3446 are producers). DEEP/ULTRA DEEP WATERS In a renewed drive to increase exploration activities and pursuant to government’s determination to increase the national reserves base to 30 billion barrels by 2003 and 4D billion barrel by 2010. The Government thought it wise to expand their exploratory horizons to deep water depth. Initially, they could only drilled water depth below 200m but later on, they increase depth drilled to between 500-1900metres, which thus tripled their discovery. (DPR, 2003) stated that this area cover about 155, 891.oqsqkm acreage holdings by 44 operators, 18,99.00km of 2D had been acquired by Mabon, PGS and Veritas as well as 31,332.345sqkm of 3D which had also been acquired by PGS and Veritas. TABLE 1: A summary of data obtained from all sedimentary basins

BASIN

1

Bida

NO OF SEISMIC WELLS DATA AVAILABLE 2D

2

Anambra

3

2D

3

Sokoto

0

2D

4

Chad

23

2D

5

Benue Trough

3

2D

6

Benin

7

Niger Delta

2D/3D

4,493

2D,3D &4D

PETROLEUM THICKNESS POTENTIALS BASED ON 2D Likely prospects 1000m-3000m for deep dry gas 3tcf of gas 6000m

WATER DEPTH

.

No evaluation 1220m and made so far 1980m towards the north of the basin Gas found in non commercial quantities but oil has been found in the Sudanese and Chadian side of this basin Approximately 2 tcf of gas 156mmbbls of 2500m crude oil and 1.5tcf of gas 36 mmmbbls of 75,000m crude oil and 182 tcf of gas

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2nd International Conference On Engineering Research & Development: 1113 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 1: A diagram showing all the sedimentary basins in Nigeria and their geological locations

3. SEISMIC EVALUATION OF THESE SEDIMENTARY BASINS

Considering the seven sedimentary basins reviewed so far, it is obvious that the Bida, Anambra, Sokoto, Chad basin and the Benue Trough are the only basins where no other technique other than the 2D have been utilized. The Benin basin and the Niger delta basin have both experience the effect of 2D and 3D, while the Niger Delta basin remains the only basin where 4D has been employed. In the world today, much improvement have been made in the area of seismic technology, (liqing X., 1996) stated that the transition from 2D to 3D resulted in improved recovery efficiencies that have increased from 25 – 30% of oil – place with 2D control, to 40 – 50% with the 3D coverage. The recovery efficiency is also expected to increase with 4D coverage to 65 – 70% of oil – place. Another improved seismic technique is the 3D. This was adopted because of the inherent limitations of the 2D, the use of 3D has thus enhanced reservoir imaging and reservoir description. Even at this improvement a lot of zones are still by- passed. (Liqing X., 1996) stated that more than half the oil and gas in every field in the world today is by- passed. Thus, the use of 4D provides an absolute answer to the issue of proper delineation of hydrocarbon zones because of its ability to sense the real pattern of drainage of oil inside the reservoir. Therefore, from table 1 above, it can be deduced that not much has been done in the area of sedimentary technology applied in these other sedimentary basins. Subsequently, the unfavourable results based on the 2D seismic carried out in these other basins have not actually stimulated the interest of operators to drill wells. For instance, in the whole Benue Trough only 3 wells have been drilled. In Sokoto basin, no well have been drilled. In the Anambra basin, only 3 wells have been drilled. These numbers of wells are rather too small to make conclusive remarks. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1114 Innovations (15th – 17th April 2008), Benin City, Nigeria

4.

CONCLUSION

It is an obvious fact that little exploratory work has been carried out in these other sedimentary basins with the exception of Niger – Delta basin. Most operators geared all their attention and resources towards the Niger Delta with a mindset that only the Niger – Delta basin is prolific. If these operators could redefined their mindset and not overrule the possibility of more oil discoveries by implementing strategies like improving the seismic technology employed so far in these other sedimentary basins like the Sokoto, Chad, Bida, Anambra basin and the Benue Trough from 2D to 3D while adopting 4D in the Benin Basin and the more 4D’s in the Niger – Delta basin. This would no doubt help to discover more potential hydrocarbon zones and by - passed zones thus helping the nation to meet its desired target of 40 billion barrels of crude reserve and production rate of 4million barrels/day come 2010. 5.

REFERENCES

1) Nwaezeapu A.U, “Focusing on Petroleum Exploration in the Northern Region of Nigeria”, Houston, U.S.A, 2001. 2) Department of Petroleum Resources, lagos, Nigeria,”Business Opportunities in Nigeria and the E&P Environment”,Oslo, Norway,2003. 3) Olugbemiro R.O, Ligouis B. and Abaa S.I.,” The Cretaceous Series in the Chad basin, NE Nigeria source rock potential and the thermal maturity” ,journal of petroleum Geology 20(1), pp 51 – 68 4) Indigopool, ”Geology and petroleum of Nigeria sedimentary basins” 5) Yahaya M., “ Predictive Petroleum System Model of propective Anambra Basin”, Nigeria 6) Olabode S.O, Adekoya J.A., “Basement Induced Active Faults and their effects on the cretaceous and tertiary sedimentary successions in Offshore Benin”, Akure, Nigeria 7) Liqing X., Roger A., Albert B., Wei H.,” How 4D Seismic Monitoring Works” AAPG Explorer, Palisades, New York, October 1996. 8) Online Nigeria, ”The Southern Chad basin”

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2nd International Conference On Engineering Research & Development: 1115 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08079) DETERMINATION OF NEEDED WORKFORCE IN THE OIL SECTOR: LEONTIEF APPROACH. Simon D. Okonta(1) and Dr. (Mrs.) C.R. Chikwendu(2) Dept. of Statistics, Delta State Polytechnic, Otefe- Oghara, ([email protected]) (2) Dept. of Mathematics, Nnamdi Azikiwe University, Awka ([email protected]) (1)

Leontief (1996) studied the production and flow of goods in an economic system by means of models that can be written in a matrix form. His studies considered a case where the economy of nation can be divided into n-sectors of industries producing goods and services. He assumed that each sector produces a single item, each of which may be used as an input to any other industry. A mathematical model for the analysis of the workforce (employment level) was developed thus: Let L = (L1,L2, …, Ln) be row vector denoting the value of labour used up by each of the n sectors as input in order to produce output Xi. If li, i = 1,2, …, n represents the number of workers required for a unit output of sector i, then we have li = Li Xi n

Then LT =



li Xi

i 1

i.e

LT = l ( I – A)-1d --------------------------------------------*

* enables any planner to determine the number of workers needed in each sector given each sector final demand. The paper used the estimates prepared as an integral part of the Nigeria Economic Production Account of the Oil Sector which of course was derived from an intensive study for a period of seven years. A 10 X 10 matrix of Nigeria Oil Sector were examined. With simple calculation, unit labour needed in each sector in the oil industries was generated. Consequently, the estimate number of total work force needed in the industry is derived. Hence, enabling the planners to handle the employment problem in the nation.

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2nd International Conference On Engineering Research & Development: 1116 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08153) Pressure interference behaviour of both horizontal and vertical well combination in an infinite – acting reservoir system

P.U. Giegbefumwen and E.S. Adewole Petroleum Engineering, Dept., University of Benin, Nigeria E-mail: [email protected]

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2nd International Conference On Engineering Research & Development: 1117 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08154) Determination of flow regimes of a horizontal well in an infinite-acting reservoir system

K.E. Ovwigho and E.S. Adewole Petroleum Engineering, Dept., University of Benin, Nigeria E-mail: [email protected]

[ For the detailed document go to page 1562]

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2nd International Conference On Engineering Research & Development: 1118 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08177) Assessment of refining schemes for crude oil processing using Microsoft Excel

H.N. Johnson and S.E. Ogbeide Dept of Chemical Engineering, University of Benin, Benin City, Nigeria E-mail: [email protected]

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2nd International Conference On Engineering Research & Development: 1119 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08221) Risk evaluation of pipeline failures: A Nigeria perspective

G.O. Ariavie, O.P. Aigbe, O.K. Ezeaku, S.A. Omojowo and K.H. Usiagwu, Dept. of Mechanical Engineering, Univiersity of Benin, Benin City, Nigeria e-mail: [email protected], [email protected] Recent oil spills in the Niger Delta have challenged the industry to reassess (and more aggressively pursue) Pipeline failure models and prevention measures adopted thereafter. And the many production locations that are situated in close proximity to local populations, there is an increased skepticism of the sincerity of both industry and government commitment to pipeline failures prevention. More worrisome is the increased occurrences of these failures occasioned by vandalisation. Responding to these concerns, a Risk Management Analysis based Pipeline Integrity Management principles is the focal point of this project which would significantly enhance pipeline failures prevention and detection efforts. Information on approximately 350 pipelines and flow lines situated in various habitats including environmentally sensitive, mangrove swamp, agricultural lands and offshore were collated and analyzed. The Risk Management also estimates likelihood and consequences of potential failure scenarios, caused by both corrosive and non-corrosive factors. Leak prevention proposals are then evaluated based on how effective they are at reducing risk.

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2nd International Conference On Engineering Research & Development: 1120 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08263) Optimisation of Managed Pressure Drilling with Casing M. B.Oyeneyin1 , V.C. Kelessidis2. 1. Virtual Well Engineer Ltd/Robert Gordon University, Aberdeen, UK 2. University of Crete, Greece; Casing drilling can be an effective method of reducing drilling costs and minimising drilling problems but its uptake around the world has been slow with only a few wells drilled so far with casing. Complex geological features like the high overburden on top of shallow unconsolidated reservoirs characteristic of offshore West Africa can benefit from casing drilling when effectively combined with Managed Pressure Drilling technique. For the industry to develop a managed pressure drilling capability that will allow today’s generation of complex wells to be drilled safely with casing, it is necessary to develop models that include the effect of eccentricity , rotation and fluid rheology at bottom hole conditions on flow and pressure regimes, and to embed these models within an easy to use, intuitive well design package for pre planning and as a real time tool to monitor and provide forward simulations based on real time rig and downhole data. The paper presents new results of the theoretical predictions of the wellbore pressure regimes incurred when different types of drilling fluid flows in concentric and eccentric horizontal annuli. The concentric and eccentric casing drilling results are compared with parallel predictions from conventional drillstring results from developed analytical solutions integrated into the VisWELL(DeskTop Simulator) , which is used in simulating well operations. Hence, the paper presents not only provides much needed data but also verifies analytical and numerical solutions to define different MPD operating windows for casing drilling. Results, Conclusions Full range of flow curves for three flow types, two geometrical configurations and three MPD techniques are presented. The laminar-turbulent transition points are well defined both from the data and from the analytical and the numerical solutions. Live well data are subsequently used to validate the predictions. Eccentric flow pressure losses for HB fluids are generally lower than concentric, and the deviation is well predicted and validated by the VisWELL using live well data. Effects on casing string dynamics are also presented.

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2nd International Conference On Engineering Research & Development: 1121 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08274) A NEW CORRELATION FOR THE VISCOSITY OF NATURAL GAS

Ohirhian, P.U.

Department of Petroleum Engineering, University of Benin, Benin City, NIGERIA E-mail : [email protected] and I.N. Abu, Shell Petroleum Development Company P.O. Box 230, Warri , NIGERIA

ABSTRACT A new equation for the viscosity of Natural Gas under Reservoir conditions has been developed. The equation was obtained by the analysis of experimental Pressure, Volume and Temperature (PVT) Data of Gas associated with Nigerian Crude Oil. The PVT Data were those of renowned companies that operate in Nigeria. The pressure ranged from 144 psia to 4100 psi, and a temperature varied between 130oF and 220oF. Comparison of the equation formulated in this work with experimental PVT viscosity gave an average absolute error of 1.55%, a maximum absolute error of 4.878% and a standard Deviation of 1.29. Acomparison of viscosity obtained from the charts of Carr et al and the equation of Lee et al with Nigerian PVT viscosity showed that the new equation gave more accurate result. Since some Correlations perform better when applied to data from which they were derived, a further comparison test test was performed. In this test, the new equation was used to solve two problems for which solutions by the method of Carr et al were available. The first problem from the Handbook of Natural Gas Engineering by Katz et al gave a viscosity of 1.158cp while the new equation gave 1.157cp. The second problem from Ikoku’s book (Natural Gas Production Engineering) gave a viscosity of 1.178cp and the new equation also gave 1.178cp. This closeness of the viscosity of the new equation to the values from the Carr et al method proved the applicability of the new equation to any type of Natural Gas.

INTRODUCTION The viscosity of natural Gas is an important parameter that occurs in the equations for single and multiphase flow in Petroleum Reservoirs, in equations for single and multiphase flow in tubing and transmission to the market place. The two methods of obtaining the viscosity of Natural Gas available in the Literature are those of Carr et al and Lee et al. The method of Carr et al is by the use of charts obtained by experimental measurements of the Gas viscosity.. The equations that curve fit these curves are not available in the literature. Application of these charts to Nigerian Natural Gas had absolute errors that ranged form 0.00 – 10.68 %. The equations of Lee et al even gave higher absolute errors. In this work, the need to generate a simple and yet fairly accurate equation was met. The approach to the calculation of the viscosity of Gas in this work was to relate the viscosity to other Gas properties(such as Formation Volume Factor and Relative Density) which can be obtained from pressure volume (PVT) Data or from Data available in the Literature. The gas viscosity was plotted against the ratio of the Gas volume Factor (Bg) to the Gas Relative Density (Rg). The Gas volume factor is easily calculated when the Gas Deviation Factor (z) is known. There are several methods of obtaining the Gas Deviation Factor in the Literature. The Gas Relative Density (which is the ratio of the Molecular weight of the Gas to the molecular weight of Air) can be obtained from experimental Data. There are no ready-made equations to estimate the Gas Relative Density of Natural Gas. Because of the lack of ready made equations for estimating the Gas Relative Density, we developed an empirical equation that can be used to estimate the Gas Relative Density. When this empirical equation was substituted into the ratio of the Gas Volume Factor to the Gas Volume Factor (Bg / Rg), the ratio reduced to a grouping that involves only presure(p), temperature(T), and the Gas Deviation Factor(z) . pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1122 Innovations (15th – 17th April 2008), Benin City, Nigeria This work involved the study of Natural Gas viscosity at elevated Pressure that ranged from 144 to 4100 psia and Temperature in the range 130 – 220 oF. The viscosity form the new equation was compared with e experimental PVT viscosity used to develop the equation. The mean absolute error between the viscosity estimated by the new equation and experimental(PVT) viscosity was 1.55% and the maximum absolute error was 4.878%. A test was also made to see the applicability of the new equation to foreign Natural Gas. A problem worked as example 2.12 in the Book of Ikoku titled Natural Gas Production Engineering was solved by the new equation and the result compared with that obtained by Ikoku who used the procedure of Carr et al. The new equation gave a viscosity of 0.0178 c p ,and the method of Carr also gave 0.0178 cp. The new equation was also tested with another problem in the Handbook of Natural Gas Engineering written by Katz et al. The Book also used the method of Carr et al and obtained the Gas Viscosity as 1.158cp while the new equation yielded 1.157cp. The closeness of the viscosity obtained by both methods confirmed the general application of the new equation; at least with the limit of the variables used to develop the new correlation. DEVELOPMENT OF THE NEW CORRELATION In this work, the Viscosity of Gas associated with Nigerian Crude Oil ( ì g ) measured in centipoise was plotted against a dimensionless group on a Log – Log graph paper. The dimensionless group used is the Gas Relative Density (R g) divided by 100 times the Gas Volume Factor (100Bg) The plot involved 148 Viscosity Data drawn from 25 Reservoirs in the Niger Delta Province of Nigeria. The graph turned out to be that of a rational function. The graph paper used was very large and the scaled down version of the original plot is shown in figure 1.

We found empirically that the Gas Relative Density (R g) can be computed by :

0.001031PT ------------------------(1) P  0.061T where P  Pressure, psia Rg 

T  Tempereature o R The standard equation for the dimensionless Gas Volume Factor (B g) is:

Bg 

0.0283zT -------------------------(2) P

where P  Pressure , psia

T  Temperature , O R z  Gas Deviation Factor

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2nd International Conference On Engineering Research & Development: 1123 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 1: Plot of Ratio of Gas Relative Density to Gas Volume Factor The Graph of

 g versus Rg / (100Bg) shown in figure (1) is that of a rational function which can be

described by an equation of the type :



g



ax 2  bx  c 2

-----------------------(3)

dx  ex  1

where x  Rg / ( 100Bg ) and a, b, c, d, e are real constants. To determine these constants 5 well spaced co – ordinates of the Graph in figure 1 were selected and substituted into equation (3) which resulted in 5 simultaneous equations. The solution of the simultaneous equations gave the Constants as: a = - 0.0075720 b = - 0.0088234 c = 0.0109388 d = 0.0461989 e = -1.3633077 Substitution of these values into equation (3) gave the equation of the calculating gas viscosity at elevated pressure as :

g 

0.0109388 - 0.0088234x - 0.0075720x2 - - - - - - - - - - - - - - - - - - - - - - - (4) 1.0 - 1.3633077x  0.0461989x 2

Where:

 g  Viscosity of gas at elevated pressure, (cp)

x  R g / (100Bg) When equation (1) is substituted in x = R g / (100Bg), x becomes x

0.0059723 p T z (16.393443  ) p

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - (5)

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2nd International Conference On Engineering Research & Development: 1124 Innovations (15th – 17th April 2008), Benin City, Nigeria p T

= =

z 

Pressure, (psia) Temperature,( o R) Gas Deviation Factor

ACCURACY OF THE CORRELATION To test the accuracy of the newly developed equations, they were used to compute the viscosity of the Gas from Samples drawn from the 25 Reservoirs used to develop the correlation. The calculated values of Gas viscosity were then compared with PVT values. After this comparison viscosity of the samples as obtained by the charts of Carr et al and equations of Lee et al were also compared with the corresponding PVT viscosity. Sample calculation and comparison with PVT Viscosity Table 1 is a PVT data of one of the Reservoirs used to develop the correlation. Example 1: Given that the Gas gravity (air = 1) of the Gas associated with the Reservoir in Table 1 is 0.696. Calculate the viscosity of the Gas at 3015, 2315, 1615, 1015, and 515, psia by the new equations assuming that : (a) Only the given Gas Gravity is the parameter available (b) Values of B g and R g are available from a PVT Report Solution (a)

We shall illustrate the use of the equation (4) by the calculation of the Gas Viscosity at the pressure at 3015 psia.

Step1: Obtain the Gas Deviation Factor (z) T = 166oF = (166 + 460) o R By use of the Thomas, Hankinson and Philip equations for the pseudo critical constants, P PC = 709.604 –58.718 S.G PTC = 170.491 + 309.344 S.G Substitution of given S.G gives P PC = 668 psia PTC = 384 OR 3015.0 626.0 PPR =  4.51, PTR   1.63 384.0 668.0 From the chart of Standing and Katz (which is expected familiar to the reader)

z  0.84 Step 2. Calculate the Ratio: x  Rg / (100 Bg) by use of eqn.(5)

x  Rg / (100 Bg) 

0.0059723  3015  1.3399 626.0 0.84(16.393443 ) 3015

Step 3.Substitution of the value of x obtained instep 2 into equation (4):

g 

0.0109388  1.3399 - 0.0088234  1.3399 - 0.0075720  1.33992  0.0195 cp 1.0 - 1.3633077  1.33599  0.0461989  1.33992

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2nd International Conference On Engineering Research & Development: 1125 Innovations (15th – 17th April 2008), Benin City, Nigeria Table 1 :DIFFERENTIAL VAPORIZATION OF RESERVOIR FLUID: AT: 166.0 F (347.6K) 1 – OIL PHASE PROPERTIES Pressure Psia 5015 4765 4515 4265 4015 37.65 pb = 3557 3015 2315 1615 1051 515 15

Mpa 34.58 32.85 31.13 29.41 27.68 25.96 24.52

Oil volume factor, Bo Vol/svol 1.709 1.715 1.721 1.728 1.734 1.742 1.747

20.79 15.96 11.14 7.00 3.55 0.10

1.644 1.523 1.416 1.333 1.263 1.052

Solution Gas-Oil Ratio, Rs scf/sbb1 sm3/sm3

1372

244.3

1150 883 641 452 301 0

204.9 157.4 114.1 80.6 53.5 0.0

Residual Oil relative density at standard conditions: API gravity:

Reservoir Oil density g/cm3 0.633 0.631 0.629 0.626 0.624 0.621 0.619

kg/m3 633 631 629 626 624 621 619

0.637 0.661 0.685 0.706 0.724 0.787

637 661 685 706 724 787

0.829

39.1

2- GAS PHASE PROPRETIES Pressure Psia 3015 2315 1615 1015 515 15

Mpa 20.79 15.96 11.14 7.00 3.55 0.10

Gas volume, factor, Bg Vol/svol 0.0048 0.0063 0.0092 0.0151 0.0317 1.1736

Z

0.823 0.819 0.836 0.864 0.922 0.995

Gas Viscosity cp 0.0205 0.0178 0.0155 0.0135 0.0117 0.0073

MPa.s 0.0205 0.0178 0.0155 0.0135 0.0117 0.0073

Gas rel. density 0.710 0.699 0.704 0.722 0.777 1.316

Table 2 shows the values of Gas viscosity computed by the new equations, the corresponding PVT viscosity and associated values of absolute errors. Pressure Viscosity, this study (cp) P.V.T Viscosity (cp) Absolute Error (%) ( Psia ) 3015 0.0194 0.0205 4.878 2315 0.0175 0.0178 1.685 1615 0.0157 0.0155 1.290 1015 0.0138 0.0135 2.222 515 0.0122 0.0117 4.273 Table 2: Comparison of Calculated viscosity with PVT Viscosity where only G g is available. (b) (i) At a pressure = 3015psia ,Table 1gives B g = 0.0048 and R g = 0.710 Then R g / (100Bg) = 1.4792 Substitution of given values into equation (4 ) gives g = 0.0204 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1126 Innovations (15th – 17th April 2008), Benin City, Nigeria Table 3 gives the errors of the viscosity when B g and R g are available from PVT Data. Pressure Viscosity from the P.V.T. Viscosity Absolute Error (Psia) study (cp) (cp) (%) 3015 2315 1615 1015 515

0.0204 0.0179 0.0153 0.0139 0.0124

0.0205 0.0178 0.0155 0.0135 0.0117

0.488 0.562 1.290 2.963 5.983

Table 3: Errors associated with this correlation when both B g and R g are available from PVT of the sample Reservoir. Table 4 shows the absolute errors of this study (equation 4)., and the corresponding absolute errors by the method of Carr et al and the equation of Lee et al.; for a sample of 8 Reservoirs used to develop the new correlation. The original plot had 148 Data points taken from 25 Reservoirs. In applying equation (4) it is assumed that a PVT Report is not available and only the Gas Deviation Factor is available. The absolute error in tables 4 and 5 is defined as:

Vest(i) - Vexp(i) V exp(i)

Absolute Error ( D i ) 

 100 % - - - - - - - - - - - - - - - (6)

Where:

Vest (i )  Viscosity obtained by estimation V exp (i)  Viscosity from PVT Report Other statistical parameter used to test the accuracy of equations 4 and 5 are the mean absolute error (M.E) and the standard deviation (SD). The equation used for mean absolute error (M.E) in this study is: M.E

=

 Di n

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - (7)

Where n = number of Data points The equation for the Standard Deviation is :

SDi 

1  1 2 2   Di -   Di   - - - - - - - - - - - - - - - - - - - - - - - - - - - - - (8) n -1  n 





Table 5 shows the application of all the statistical parameters used in this study to the equation of this work , and the corresponding values from the Carr et al method, and the equation of Lee et al. Table 5 shows that the new Gas Viscosity equation performed best for Nigerian Natural Gas. The equation of Lee et al had the poorest performance with a maximum error of 12.00% and a standard deviation 3.22. Many correlation perform best for data from which they derived so there is need to test the new equation on a foreign Natural Gas. The correlation of Carr et al was chosen since it performed closer to the new equation in Nigerian environment. If the viscosity computed by the new equation is close to the value obtained by Carr et al charts (by use of Carr et al Data), then the application of the new equation to foreign Natural is ascertained. GENERAL VALIDITY OF THE NEW ELEVATED PRESSURES EQUATION To test the applicability of the new equation to Gas that exists in a foreign Reservoir, the equation was applied to two problems for which the solutions by the Carr et al method were available. The first problem was example 2.12, page 58 of the book of Ikoku; Natural Gas Production Engineering.. The problem and its solution are as follows:

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2nd International Conference On Engineering Research & Development: 1127 Innovations (15th – 17th April 2008), Benin City, Nigeria Table 4 : Data Point 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Comparison of Estimated Viscosity of gas from present study, correlation of Carr et al and Lee et al Experimental Viscosity from correlation Deviation % From Experimental Viscosity This study Carr.et al Lee et al This study Carr. Et al Lee et al (cp) 0.0205 0.0195 0.0224 0.0215 4.878 9.2 4.9 0.0178 0.0175 0.0189 0.0181 1.6 6.2 1.6 0.0155 0.0157 0.0153 0.0156 1.3 1.3 0.65 0.0135 0.0138 0.0142 0.0141 2.2 4.8 4.4 0.0117 0.0122 0.0119 0.0126 4.2 1.7 7.7 0.0165 0.0169 0.0179 0.0171 2.4 7.8 3.3 0.0151 0.0154 0.0156 0.0154 1.9 3.3 1.9 0.0138 0.0139 0.0144 0.0141 0.73 4.3 2.2 0.0125 0.0125 0.012 0.0132 0 4 5.3 0.0113 0.0117 0.012 0.0126 3.5 6.2 12 0.0164 0.0166 0.0165 0.0168 1.22 0.73 2.4 0.0151 0.0153 0.0153 0.0155 1.3 1.3 2.5 0.0139 0.0137 0.0142 0.0144 1.4 2.2 3.5 0.0127 0.0126 0.013 0.0135 0.99 2.4 6.5 0.0118 0.012 0.0118 0.013 1.7 0 10.2 0.0186 0.0187 0.0201 0.0208 0.54 8.06 11.82 0.0168 0.017 0.0177 0.0183 1.2 6.4 8.9 0.0151 0.0154 0.0153 0.016 1.98 1.32 5.9 0.0135 0.0136 0.0136 0.0143 0.74 0.74 5.9 0.0122 0.0122 0.0118 0.0132 0 3.3 8.2 0.0171 0.0174 0.0178 0.0178 1.7 3.9 3.9 0.0157 0.0158 0.0166 0.0162 0.64 5.5 2.9 0.0144 0.0145 0.0144 0.0148 0.69 0 2.9 0.0132 0.0132 0.0132 0.0138 0 0 4.2 0.0118 0.0119 0.012 0.013 0.85 1.7 10.3 0.0172 0.0172 0.0174 0.0179 0 1.16 4.3 0.0157 0.0156 0.0161 0.0163 0.64 2.7 3.8 0.0144 0.0146 0.014 0.0149 1.4 2.5 3.35 0.0131 0.0133 0.0117 0.0138 1.5 10.68 5.35 0.0119 0.0121 0.0116 0.0129 1.67 2.6 7.75 0.0182 0.0183 0.0171 0.0187 0.54 6 2.8 0.0166 0.0166 0.0165 0.0169 0 0.6 1.8 0.0151 0.0151 0.0151 0.0153 0 0 1.58 0.0136 0.0135 0.0135 0.0138 0.77 0.77 1.6 0.0122 0.0123 0.0121 0.013 0.81 0.81 6.8 0.0165 0.0171 0.0165 0.0162 3.42 0 1.8 0.0151 0.0155 0.0153 0.015 2.8 1 0.51 0.0138 0.0144 0.0144 0.014 4.3 4.3 1.44 0.0125 0.013 0.0132 0.0131 4 5.6 5 0.0113 0.0116 0.0122 0.0126 2,70 7.9 11.7

Statistical parameter Average absolute error % Minimum absolute error % Maximum absolute error % Standard deviation

This study 1.55 0.00 4.878 1.29

Carr et al 3.30 0.00 9.20

Lee et al .4.84 0.51 12.20 3.22

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2nd International Conference On Engineering Research & Development: 1128 Innovations (15th – 17th April 2008), Benin City, Nigeria 2.84 Table 5: Statistical accuracy of Gas Viscosity of this study, Carr et al method and Lee et al method. Example: 2 A sour Gas has the following characteristics: Ma = 20.15 g = 0.70 PTC = 381.8oR PPC = 733.3 psia z = 0.850 Determine the Viscosity of the Gas at 180oF and 2500 psia. Solution by the new equation (equation 4) is as follows Substitution of the given values of P ,T and z into eqn.( 5) gives

0.0059723  2500  1.0885 640.0 0.85(16.393443 ) 2500 Substitution of this value of x into equation (4) gives g = 0.0178 cp. This value is the same as g = x  Rg / (100 Bg) 

0.0178 cp obtained by Ikoku who used the Carr et al method. The second test problem came from the Handbook of Natural Gas Engineering written by Katz et al. The problem and its solution are presented in example 3 that follows. Example 3 Find the Viscosity of a natural Gas of 0.702 Gravity at 195 o F and 1,815 psia. Solution by the new equation (equation 4) is as follows From the Handbook of Natural Gas Engineering, PPC = 667 psia , PTC = 390 o R PPR = 1815 / 667 = 2.72 , PTR = 655/390 = 1.68 From the Compressibility Factor Chart of Katz et al (assumed to be familiar to the reader), z = 0.86 Substitution of the values of p, t and z into eqn.(5) gives:

0.0059723  1815  .7862 655.0 0.86(16.393443 ) 1815 Substitution of this value of x into equation (4) gives g = 0.0157 cp. This value is very close g = x  Rg / (100 Bg) 

0.0158 c p obtained in the Handbook of Natural Gas Engineering!

1. 2

CONCLUSIONS A new equation for calculating the viscosity of Natural Gas at elevated pressures and temperatures has been developed. The equation needs less variables to calculate the Gas viscosity.

REFERENCES 1. Carr, N.L., R. Kobayashi and D.B. Burrows (1954). “Viscosity of Hydrocarbon Gases under Pressure”. Trans AIME 201, pp 264-272 2. Katz, D.L et al(1959), Handbook of Natural Gas Engineering, McGraw-Hill Book Company, New York,p174 3. Ikoku, C.U., (1984), National Gas Production Engineering., John Wiley & Sons, New York, p 58. Lee, A.L., M.H. Gonzalez, and B.E Eakin (1966). “The viscosity of Natural Gases”. Journal of 4. Petroleum Technology, p 997 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1129 Innovations (15th – 17th April 2008), Benin City, Nigeria

TECHNICAL SESSION 8A: MACHINES AND EQUIPMENT III

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2nd International Conference On Engineering Research & Development: 1130 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD08023) Design and Development of Palm Waste Briquette Stove for Domestic and Industrial Usage C.O. Ilechie (1), G.F. Aibangbee (2) and S.R. Ogblechi (3) Agric Engineering Research Division, Nigerian Institute for Oil Palm Research(NIFOR), P.M.B. 1030, Benin City, Edo State – Nigeria. e-mail: [email protected](2), [email protected](3). ABSTRACT: A low cost heat-conserving stove that uses palm waste briquette (substitute for fuel wood) has been developed. It has a furnace size of 400mm diameter and a height of 400mm with a 90mm inner cylindrical burner. The heating surface of the stove generated about 966 kilojoules of heat. A natural draught of 6m/s (efflux velocity) was used to determine the chimney size. The stove which was designed and fabricated mostly from 3mm low carbon steel (mild steel) material can accommodate different sizes of briquette for both domestic and industrial cooking. The air inlet has a regulating duct that controls the burning of the briquette. The burning rate of the palm waste briquette using the briquette stove was estimated to be approximately 3.0kg/hr. This value was found to be lower than values obtained when the same quantity of briquette was burnt in the open air. The technology is recommended for adoption by women preparing snacks (i.e. roasted yam. Plantain, corn, e.t.c) in market places and along commercial roads. Keywords: palm waste briquette, stove, chimney, industrial, domestic heat.

1.0 INTRODUCTION Various types of cooking stoves exist in Nigerian market. There are those that use kerosine, diesel, cooking gas (methane, ethane, etc), coal, charcoal, firewood and sawdust. Among these fuels, firewood has been the cheapest and easy to get in most developing countries. It is the most widely used household fuel in Nigeria. Virtually every rural family rely on it for all or parts of its cooking. Indeed, it is the predominant cooking fuel for the poor and the middle class [1]. The over dependence on firewood as source of fuel has led to massive deforestation and uncontrolled logging. This resulted in rapid disappearance of the natural forest. Non-availability or insufficient supply of kerosine (an alternative heating and cooking fuel) and other forms of fuel in Nigeria has further compounded the problem of deforestation and desertification Fuel wood has been utilized using several media for ages past but these methods have not been able to remove deforestation and desertification. Dr. Winiarski designed and developed an Institutional Rocket stove that is efficient and uses less firewood when compared to the conventional method (open fire) [2]. The problem was still not completely solved since the use of the stove for heating and cooking still depends completely on firewood. It is in view of this that Nigerian Institute for oil palm Research developed an alternative energy source called palm waste briquette. This is easy to make, reliable, affordable, user friendly and burns with high heat intensity [3, 4].

THE NEED FOR BRIQUETTE STOVE In the urban and rural areas, women engaged in various forms of cooking and preparation of snacks such as roasting of plantain, yam, corn, meat, fish, etc. They use firewood or charcoal in the roasting but studies have shown that the process is cumbersome with lot of energy losses. The need arose to develop a technology that is friendly and conserve energy during snacks preparation. The amount of heat passed into pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1131 Innovations (15th – 17th April 2008), Benin City, Nigeria the food decreases when the roasting is done in open air (conventional method) as the combustion chamber is opened to spontaneous and uncontrolled burning. Traditionally, bricks were used to form combustion chamber but these were still unsatisfactory. The development of a cheap, renewable, available and friendly energy source (palm waste briquette) means that firewood could be substituted completely. Attempts to utilise the palm waste briquette showed that it could burn more economically in a closed system. This necessitated the design and development of a low-cost heat conserving stove that uses palm waste briquette as means of heating or cooking. 2.0 METHODOLOGY 2.1 STOVE DESIGN The main body of the briquette stove was made from 3mm low carbon steel (mild steel) which has a diameter of 400mm and a height of 400mm with an inner cylindrical burner. The top cover of the stove is the hot plate that converts energy generated from burning of palm waste briquette to useful heat. The hot plate is made from 4mm mild steel with five number 16mm low carbon steel rods welded to the posterior side of the cover. The rods absorb and transfer heat for useful energy.

2.1.1 ESTIMATION OF USEFUL ENERGY The heat for heating and cooking purposes is by conduction through the hot plate. This was determined from equation (1) q = mc0------------------------------------ (1) Where q = quantity of heat emitted by hot plate m = mars of hot plate (top cover) c = specific heat capacity of mild steel 0 = temperature difference (oC) The heat generated by the heating surface (hot plate) was where mass of plate = 10Kg specific heat capacity = 0.46KJ/KgoC temperature = 210oC

determined to be 966KJ.

2.1.2 ESTIMATION OF CHIMENEY PIPE SIZE (DIAMETER) A natural draft of 6m/s (efflux velocity) was used to determine the chimney size of the stove [5, 6]. The chimney which is attached to the side of the stove removes efflux gases (smoke). By natural convection the hot gases moved upwards and out through the chimney. The chimney size was determined using equation (2). Q = A x V ____________(2) Where Q = flow rate of fuel gases at chimney temperature in m3/sec v = velocity of fuel gases (m/s) A = cross sectional area of chimney. The diameter of the chimney was determined to be 50mm with plate thickness of 5mm. The decision on the choice of materials was based on the followings. -

strength of material durability toughness high thermal conductivity availability ease to weld pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1132 Innovations (15th – 17th April 2008), Benin City, Nigeria 2.2

cost of materials. PARFORMANCE EVALUATION OF PALM WASTE BRIQUETTE STOVE

The following materials were used in the performance (i) (ii) (iii) (iv) (v) (vi) (vii)

evaluation of the palm waste briquette stove.

Briquette stove Palm waste briquette fuel wood (firewood) mercury-in-glass thermometer (0-360oC) Aluminium pot water stop watch (Timer)

Equal volume of water was heated to boiling point using the following methods. (i) Heating with the briquette stove using palm waste briquette (ii) Heating in open-air using palm waste briquette (iii) Heating in open –air using firewood (fuel wood). The results of the experiments were recorded. 3.0 RESULTS AND DISCUSSION Figure I and Figure II show the pictorial view and exploded assembly of the palm waste briquette stove respectively.

Figure I: pictorial view of briquette stove Table 1 shows the results of the time taken to boil fifty litres (50L) of water on the briquette stove using palm waste briquette. Table 1 Time taken to boil water using palm waste briquette and briquette stove; S/No. Weight Volume Time of of water taken to briquette (litres) boil used (kg) water (minutes) 1 2.4 10.0 48.0 2 3.2 10.0 39.0 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1133 Innovations (15th – 17th April 2008), Benin City, Nigeria 3 4 5 Total Mean value

4.0 4.8 5.6 20.0 4.0

10.0 10.0 10.0 50.0 10.0

34.0 32.0 30.0 183.0 36.6

Table 2: Time taken to boil water using palm waste briquette in open air. S/No Weight Volume Time of palm of water taken to waste (litres) boil briquette water (Kg) (minutes) 1 2.4 10.0 36.0 2 3.2 10.0 33.0 3 4.0 10.0 31.0 4 4.8 10.0 30.0 5 5.6 10.0 28.0 Total 20.6 50.0 158.0 Mean 4.0 10.0 31.6 value Table 3 shows the results of the time taken to boil 10 litres of water in open air using fuel wood. The results from the tables show that the briquette stove boils 10 litres of water at an average time of 36.6 minutes and palm waste briquette boil 10 litres of water at an average time of 31.6 minutes in the open air. Similarly fuel wood boils 10 litres of water at an average time of 53 minutes in the open air. Table 3: Time taken to boil water using fuel wood in open air SN Weight Volume Time of fuel of water taken to wood (litres) boil (kg) water (minutes) 1 2.4 10.0 62.0 2 3.2 10.0 58.0 3 4.0 10.0 50.0 4 4.8 10.0 48.0 5 5.6 10.0 48.0 Total 20.0 50.0 266.0 Mean 4.0 10.0 53.2 value It takes the stove about 10 minutes to heat up. This delay period notwithstanding, the briquette stove still boils water faster than boiling the water with the same briquette in open air or boiling with firewood. Palm waste briquette required 1.87kg of energy source or N14.86 or 15 minutes less time than fuel wood to achieve boiling of the same amount of water [7]. The briquette stove has the following benefits. (i) Most of the heat energy generated is conserved and converted to useful work (ii) The briquette stove is environmentally and humanly friendly. Most of the smoke generated (over 95%) is conveyed through asmoke channel called the chimney out of the kitchen. (iii) The cooking utensils is not blackened as it is usually not in direct contact with the burning flame the briquette pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

of

2nd International Conference On Engineering Research & Development: 1134 Innovations (15th – 17th April 2008), Benin City, Nigeria (iv) It incorporates air-shut devices (air regulatory devices). This put off the flame when all outlets are completely shut and; the outlets also regulate the rate at which palm waste briquette burns. 4.0 CONCLUSION The palm waste briquette designed and fabricated at Agricultural Engineering Research Division of NIFOR has been found to perform effectively. The materials required for product development are cheap and readily available. The stove is convenient to use for small family size or women who roast corn, plantain, yam, etc. This will assist in alleviating poverty by providing an easy to operate cooking device that uses waste products from oil palm fruit processing mills. 5.0

REFERENCES

[1]. C.O Ilechie, P.E. Amiolemhen, G.F Aibangbee and S.R Ogblechi.Development of a Briquette moulding machine. Proceedings of the Nigerian Institution of Agricultural Engineers. Vol. 27, (2005) PP 70-72. [2]. L. Winiarski, The Institutional Rocket stove. http://ww.crest.org/discussiongroups/resources/stoves/sunsmiles/mproved-chimney.html.

website:

[3] C.O.Ilechie, U. Omoti, . M.E. Bafor, S.R. Ogblechi, ,G.F. Aibangbee and P.E. Amiolemhen, Palm waste briquette – substitute for fuel wood Journal of Engineering Research and Technology Vol.2, No. 3 (2007) PP 64-67 [4]..C. O Ilechie, U. Omoti and M.E. Bafor, Palm Waste Briquette–substitute for fuel wooo Nigerian Institute for Oil Palm Research, Benin City. (2001) [5]..L.M .Miller, Student Textbook of Heating, ventilating and Air conditioning. Technitrable Journals. 1976 pp 28-31. [6]. F .Porges, Handbook of Heating, Ventilating and Air-conditioning. 6th Edition, Vol. 3, 1971 pp 1 – 13. [7]. A. C. Ojemade, A. O. Jose, F.K. Eneh and C. O. Ilechie. production. Journal of applied Sciences Vol7 No. 2 (2004)

The Economics of Palm Waste briquettes

[8]. C.L .Mantell. Engineering Materials Handbook, 1st company, INC., New York. 1958

Edition published McGRAW-Hill Book

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2nd International Conference On Engineering Research & Development: 1135 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure II: briquette stove exploded assembly

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2nd International Conference On Engineering Research & Development: 1136 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08037) Development of an Adjustable Temperature Sensing System for a Dual Preservative Unit

B. Kareem Department of Mechanical Engineering, Federal University of Technology, Akure, Nigeria. Phone: +2348033737251, Email: [email protected], [email protected]

Abstract: In refrigeration and air-conditioning systems, heat is removed from the refrigerated space using a device called evaporator and rejected it to the environment at the condenser. The rejected heat pollutes the environment and contributes to global warming. This study develops a system in which the waste heat is being put to preservative use through incorporation of an adjustable temperature sensing device to control the heat in the warming compartment. Evaluation of the performance of the system was done by conducting tests to determine its optimal operating temperature and the effect of heat conserved on the cooling compartment. The results of the performance test were used for effective calibration of the device. The warming compartment worked effectively up to a maximum temperature of 680C without impairing the cooling compartment. Increased performance is obtainable with the incorporation of high efficient fan to force through the heat from the condenser. Keywords: Refrigeration, Dual preservative unit, Pollution, Temperature sensing, Calibration, Performance.

1.0 INTRODUCTION In developing an adjustable temperature sensing device for the dual purpose system, a bi-metallic strip thermostat is incorporated. A thermostat is a device for regulating the temperature of a system so that the system’s temperature is maintained at or near a desired set point. [1-3]. The thermostat controls the flow of heat energy into or out of the system. It switches heating/cooling system on and off as required to maintain the predetermined temperature. In preserving foods it is either to reduce the temperature to minimum or increase it more than the normal room temperature thus giving the bacteria the minimum possibility of growing rapidly. Bacteria can only grow rapidly at normal room temperature [4]. Heating and cooling have always been the most essential ways of preserving food items. Therefore, this work is necessitated by this reason among others. This work comprises essential ways of preserving food items through heating and cooling. Cooling can be referred to as refrigerating [2]. Refrigeration is the process of removing heat from an enclosed space or from a substance to lower its temperature [5]. A refrigerator uses the evaporation of a liquid known as a refrigerant to absorb heat. The refrigerant evaporates at an extremely low temperature creating a freezing temperature inside the refrigerator. The liquid refrigerant is rapidly vaporized through compression [5-9]. The rapidly expanding vapour requires kinetic energy which is drawn from the immediate area that loses energy and becomes cooler [10, 11]. Cooling caused by the rapid expansion of gases is the primary means of refrigerating today. Modern refrigeration has many applications. The first, and probably still the most important, is the preservation of food. Most foods kept at room temperature spoil rapidly. This is due to the rapid growth of bacteria. At very low temperature of about 40C, bacteria grow quite slowly [2, 4]; food at this temperature is preserved. Therefore refrigeration is the process of preserving food by keeping it cool. Other important uses of refrigeration include air conditioning, beverage cooling, and humidity control [12, 13]. Manufacturing processes also use refrigeration. Warming of food as a means of preservation is the process of increasing the temperature of the food more than normal room temperature at the environment of the object or in an enclosed space [3]. There are many ways of supplying heat of preservation; among them are electric heater pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1137 Innovations (15th – 17th April 2008), Benin City, Nigeria and natural source (solar energy). In this work the source of heat for the dual preservative cabinet is the condenser in the enclosed space. When evaluating the cycle of refrigeration from past works, there is always a considerable amount of waste in form of heat loss from the refrigerant coming from the compressor and passing to the evaporator through the condenser [14, 15]. This project work focuses on how the waste heat from the condenser could be useful. This led into the development of dual preservative cabinet. The heat rejected at the condenser act as source of heat for the warming compartment. In principle, heat removed from the cooling compartment is released into the warming unit. As the refrigerant circulates through the system it passes through a number of changes in states or conditions, each of which is called a process. The refrigerant start at some initial state or condition passes through a series of process in a definite sequence and returns to initial condition. This series of processes is called cycle. The simple vapour compression refrigerant cycle is made up of four fundamental processes: expansion, vaporization, compression and condensation. In a refrigerating system there are five basic parts which are: compressor, condenser, expansion valve, evaporator and refrigerant. The full explanation on refrigeration processes is available in literatures [14- 16]. Circulation of refrigerant in the dual preservative cabinet makes use of two states of matter which are liquid and gas. In the condenser where the heat is removed, the state of the refrigerant is changed from gas to liquid. The liquid passes to the evaporator through a metering device (capillary tube) that reduces the pressure of the refrigerant and makes it ready to absorb heat. The state of the refrigerant is changed from liquid to 100 percent gas as it absorbs heat from the evaporator and the cycle is repeated [14]. As long as the compressor is running, it imposes a force on the refrigerant to continue circulating around the loop and continue removing heat from one compartment (evaporating) and rejecting (condensing) it into another area. The objectives of this project are to: determine the performance of an indigenously developed dual preservative unit; and develop an adjustable temperature sensing system to control the temperature of the warming compartment. In the development of the dual preservation cabinet, the vapour compression refrigerating system was adopted.

2. Methodology/Experimental Performance evaluation of the uncontrolled dual preservative unit which consists of cooling and warming compartments was first done. The uncontrolled dual preservative unit developed, using the principle of refrigeration, in the Department of Mechanical Engineering, Federal University of Technology, Akure, Nigeria, was used for the experiment. The dual preservative unit was put to test for 2 hours and then 6 hours to determine optimal temperature of the warming compartment. The graphical representation of the dual preservative unit with the incorporated thermostat is shown in Fig.1. The dual preservative equipment utilized the usual waste heat from the condenser and converted it to heat of warming. A challenge arose from this work was that heating in the warming compartment is uncontrollable and as a result impairing the performance of cooling unit at the evaporator side. In order to nip this problem into the bud a control system was developed utilizing electric circuit incorporated with bi-metallic strip. The control circuit was designed so that the current was firstly passed through the bi-metallic strip to the compressor unit of the equipment. As compressor worked, increased in temperature was sensed by control component placed very close to it. The setting of the control unit determined the maximum temperature required in the warming cabinet. The developed control circuit is shown in Fig. 2 and schematic diagram of the adapted thermostat based on bi-metallic strip is given in Fig. 3. A thermostat is an automatic device that regulates temperature in an enclosed area by controlling heating or refrigerating systems. Its operating principle is based on the fact that one of its components expands or contracts significantly during a temperature change. The thermostat uses a bimetallic strip, which is made of two thin metallic pieces of different composition that are bonded together. As the temperature of the strip changes, the two pieces change length at different rates, forcing the strip to bend. This bending causes the strip to make or break a circuit. The thermostat is calibrated by adjusting the screw bolt to push the spring and this was done in varying proportions. The corresponding temperature of each proportion was determined pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1138 Innovations (15th – 17th April 2008), Benin City, Nigeria through a thermometer placed inside the warming compartment. The temperature was taken immediately the thermostat tripped off and stopped the supply of current into the compressor. Different temperatures were measured for various sets of the control knob of the thermostat thereby served as basis of calibration. The thermostat used is of electrical ratings AC250V/12A, temperature setting range 0~300 ºC with tolerance ±5 ºC.

Figure 1. Refrigeration circuit of the dual preservative unit 3. Results and Discussion The results obtained when the uncontrollable dual preservative unit was firstly put into test for 2 hours then 6 hours at an ambient temperature of 270C are presented in graphical forms in Figures 4 and 5 respectively. The optimal temperature was established from the test and served as basis for calibrating developed control system. From the graph of the temperature of the cooling compartment, it was noticed that the cooling unit temperature decreases rapidly up to the duration of 20 minutes after which it steadily decreases and reaches its peak at 75 minutes after which its temperature tends to rise indicating that the peak or efficient functioning of the cooling compartment lies between 20 and 75 minutes. In warming compartment it was also observed that the temperature of the warmer increases with time for a duration of about 75 minutes after which it starts to fall. Summarily, the test results showed that when the warming compartment was being used for 2 hours it affected the performance of the cooling unit with optimal performance attained at a temperature of about 140C in 75 minutes (Fig. 4); the corresponding optimal temperature at warming side being about 680C. Further use of the preservative unit beyond 2 hours had no significant effect on the optimal results as the results were cyclic in nature (repeated) as depicted in Fig. 5. The two extreme temperatures obtained are acceptable to preservation of food items and drinks as they are not supportive to the survival of bacteria and fungi. Calibration of the control system was done based on the optimal temperatures obtained. In the calibration tests it was discovered that the first position setting of the thermostat luckily gave the results in the range of 65 - 700C for a ten sets of reading before the power supply was cut off from the system. The system was automatically on, about 20 minutes later, at a temperature of about 100C lesser than the above. The resulted temperature range is in agreement with the tolerance level ± 50C of the thermostat utilized for the control system. The diagram of the thermostat and its connection are shown in Figs. 2 and 3.

Figure 2. Electric circuit with the thermostat connection

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2nd International Conference On Engineering Research & Development: 1139 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 3. Schematic diagram of the thermostat 80 70 60

T E M P E R A T U R E (0 C )

50 40 30 20 10 0 0

20

40

60

80

100

120

140

-10 -20 TIME (MINS)

Figure 4. Temperatures of the cooling and warming compartments for 2 hours of running 80 70 60

T E M P E R A T R U R E in 0 C

50 40 30 20 10 0 0

50

100

150

200

250

300

350

400

-10 -20 -30 TIME (MINS)

Figure 5. Temperatures of cooling and warming compartments for 6 hours of running

4. Conclusions From the results it can be concluded that the warming and cooling units’ optimum performance lied between the duration of 20 – 75 minutes in which the cooling unit’s temperature was about -140C and that of the warmer, about 680C. The thermostat incorporated on the compressor could only maintain the warming pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1140 Innovations (15th – 17th April 2008), Benin City, Nigeria compartment at a maximum range of temperature of 65 - 700C (67.50C on average) which was within the tolerance level of the control system and at the same time very close to optimal performance temperature, 680C. The temperature control ability of the dual preservative unit will prevent waste of food items and drinks in homes by effectively preserving them from bacterial attack. It will be useful also in industries and laboratories for preservation of perishable items such as chemicals and raw materials. Further work is necessary in the area of developing an electronic control system which could be digital based. With the aid of electronic system it will be possible to sense and measure the temperature in the warming compartment directly instead of measuring it through the compressor unit of the dual preservative system. 5. Acknowledgement Adeyanju Gabriel Adewale, a student in the Department of Mechanical Engineering, Federal University of Technology, Akure ((FUTA), is acknowledged for his assistance during the test of the control system.

6. References [1] A.E. Abbot, “Ordinary Level Physics”, Heinemann Educational Books Ltd., UK. [2] W.J. Jone and W.F. Stoecker, “Refrigeration and Air Conditioning”, Mc-Graw Hill Book Company, Singapore, 1982. [3] J.D. Roy, “Principle of Refrigeration”, English Language Book Society, Antassac Press Ltd, UK., 1997. [4] C. Auru, A.L. Gabriel, B. Vasile and M.D. Lida, “Cooling Technology in the Food Industry, USA. [5] E.I. Bello and T.I. Ogendenge, “Basic Thermodynamics”, Ijumu Technical and Scientific Press, Nigeria. [6] R.J. Dossat, “Principle of Refrigeration”, Antassea Press Ltd. UK., 1985. [7] T.D. Eastop, and A. Mc-Conkey, “Applied Thermodynamics”, Longman group, UK., 1993. [8] O.P. Fapetu, “Principle and Practice of Refrigeration”, Pin Funky Press, Nigeria, 2002. [9] F.H. Francis, “Engineering Thermodynamic”, Macmillan Publishing Company, New York, 1988. [10] K.M. Gutkowski, “Refrigeration and Air Conditioning” Spectrum Books Ltd, Ibadan, Nigeria, 1996. [11] Handbook on Heat Transfer Fundamental 1985 [12] H.T. Hevenot, “History of refrigeration throughout the world”, International Institute of Refrigeration (HR), Paris, France, 1997. [13] W.J. Jone, “Conditioning Application and Design” Edward Arnold Publishers Ltd., 1980. [14] B.A. Nagengast, “History of Refrigeration” American Society of Heating Refrigerating and Air Conditioning, 1990. [15] W.F. Stoecker, P.S. Hrnjak and C.A. Ferreira Refrigeration and Air Conditioning Technology, Belnc Publishers Inc. U.K., 2001. [16] Handbook of American Society of Heating and Refrigerating Engineering Fundamentals 1997.

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2nd International Conference On Engineering Research & Development: 1141 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08119) DESIGN AND CONSTRUCTION OF A HUMAN BODY RESISTANCE AND TEMPERATURE MEASURING DEVICE

Ilaboya Idowu Rudolph, Department of Chemical Engineering, Gen. Abdusalam, A. Abubakah College of Engineering, Igbinedion University, Okada. PMB 0006. Okada [email protected], 08038027260.

1.0 MATERIALS AND CONSTRUCTION MATERIALS: Materials used for the construction of the circuits are copper probe, signer meters, resistors, switching transistors, LEDs, capacitors, thermistor 741 OP – Amp, 2N2222 switching transistor, 555 timers, and IC socket. CONSTRUCTION: The various components that make up the circuit were bought and the circuit was constructed stage by stage on the bread board. The necessary adjustment was made there. After each stage was certified okay with a 12D.C supply, the entire system was then transferred to a Vero board where the various components were soldered and also tested. Parts that were not required to be continuous were cut open using a razor blade. Jumper wires were used to connect certain part of the circuit which does not fall along the continuous line on the Vero board. The circuit was then arranged properly into its casing. The casing is a plastic box with dimensions of length, breadth and width of 171mm, 104mm and 55mm respectively. It carries the power on switch used only with AC, the AC to DC selector switch, the green and red LED’s and the wire splitters, the Ac cords and the sensing probes on the body of the casing. The casing cover carries three meters. 2.0 TEST The voltage divider resistors and potentiometer were used to set the input into the comparator circuit formed by two resistors thereby setting the green LED to on when the circuit is powered. First, the sensing probe was then placed on the dry human skin and the result of the indicator was noted. Then the sensing probe was placed on a humid human skin and the result was also noted. Thirdly, the sensing probe was placed across the terminals of a standard resistor and the result was also noted. Finally, the sensing probe was placed on a moist substance and the result was also noted. 3.0 RESULTS AND DISCUSSION The output display meters and the green and red LED’s were closely monitored as the test were being carried out. When the circuit was powered, the temperature meter deflects. This is the environmental temperature. TABULATED RESULTS OF THE RESISTANCE OF CERTAIN INDIVIDUAL INDIVIDUAL BODY RESISTANCE BODY RESISTANCE WITH WITHOUT MOISTURE MOISTURE (ohms) (ohms) A 1.2M 200K B 950K 1K C 1.1M 5.5K D 1.3M 15K E 890K 400K The table above shows the results of placing the probe on different individuals. When the sensing probe was placed on a dry skin, the green LED remains on and the resistance meter reads full scale deflection of about 1M ohms, the current meter reads null and the temperature meter shows the environmental temperature. When the sensing probe was then placed on a humid skin, the resistance meter deflects towards zero depending on the level of humidity or moisture, showing the reduction of the body resistance, the temperature meter deflects depending on the temperature it senses and the current meter deflects indicating that current is flowing through the circuit. The value of 1M ohms standard resistor produces full scale pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1142 Innovations (15th – 17th April 2008), Benin City, Nigeria deflection and keep the green LED on. The values of lower standard resistors produce reduced deflection and turn on the red LED. When placed on a moist substance, the device switches on and the green LED goes off while the red LED comes on. The results obtained were as expected and satisfactorily good. 4.0 1. 2. 3. 4. 5.

REFERENCES Paul H and Winfield H. “The Art of Electronics”. Second Edition, Cambridge University Press, 1989. Pp 8 – 572. Theraja B.L and Theraja A.K. “A Text Book of Electrical Technology”. Illustrative Multicolored Edition by S.C Chand and Company, 2005. Pp 375 – 378. Williams Arthur B. “Designers Hand Book of Integrated Circuits” First Edition, McGraw Hill Publishers. 1984. Pp 25 – 29. Madhuri Joshi A. “Electronics Components and Materials”. Second Edition, Wheeler Publishing and Co Ltd. New Delhi. 1995. Pp 17 - 45 Comer David J. “Modern Electronics Circuit Design”. Second Edition, McGraw Hill Publishers. 1975. Pp 45 - 52

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2nd International Conference On Engineering Research & Development: 1143 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08151) Process Conditions Affecting the Yield and Quality Attributes of Oil Mechanically Expressed from Castor

A. M. Olaniyan Department of Agricultural Engineering, Faculty of Engineering and Technology, University of Ilorin, P. M. B.1515, Ilorin 240003, Kwara State, Nigeria; e-mail: [email protected]

Abstract Castor (Ricinus communis L) is an herbaceous plant which was originated from India and cultivated in the tropical and sub-tropical climates of the world. The seed contains about 45-60 % essential oil which is used in medicine as an ointment and in food and process industries as a raw material. Using a piston-cylinder rig in association with California Bearing Ratio (CBR) Universal Testing Machine, experiments were carried out to investigate the effects of some process conditions on the yield and quality of oil after extraction. Castor seeds were shelled, cleaned, milled and graded into coarse particles and then heated in the oven at temperatures of 30, 60 and 90 0C for 30 min before oil was mechanically expressed for 8, 10 and 12 min. The same experiment was repeated for unshelled nut and whole seeds with each trial being replicated three times. The oil expressed was collected and oil yield was estimated as a percentage of the raw sample before expression. Physicochemical analysis of the oil was also carried out to determine its quality potential. The data obtained was subjected to the statistical Analysis of Variance while Duncan’s Multiple Range Test was used to compare the means. Results of the analyses show that the process conditions and their interactions were significant on oil yield at 0.05 % level of significance However, only the pressing time was significant on the extraction pressure. Oil yield increased with increased heating temperature and pressing time for the ground, whole seed and unshelled nut samples. A maximum oil yield of 41.67 % was obtained when coarsely ground sample was heated at 90 0C and mechanically expressed for 12 min while the minimum of 2.70 % was from unshelled sample heated at 30 0C and mechanically expressed for 8 min. At the conditions of maximum and minimum oil yield, the maximum extraction pressures were 135.0 and 100.3 kPa respectively. Samples of oil obtained at the condition of maximum oil yield had specific gravity, refractive index, free fatty acid, saponification value and ester value of 0.96, 1.47, 25.91, 194.13 and 143.63 respectively. Keywords:

Castor, Mechanical expression, Temperature, Pressure, Oil yield, Oil quality

1.

Introduction Castor (Ricinus communis L) is an annual crop in tropical Mediterranean climatic zones. According to Ibrahim and Onwualu [1], the major producers of castor seed and oil are India, Brazil, China, USA and Thailand with samall contributions from African countries such as Ethiopia, Tanzania, South Africa, Kenya and Nigeria. The main producing countries are India, Brazil, China and Thailand while the main importing countries are the leading industrialized countries like USA, Russia, Japan and European countries. At maturity, castor plant produces fruits which are globular with at least 3 seeds with each seed containing certain percentages of oil and protein [1, 2, 3]. The oil constitutes about 90 % recinoleic acid of the entire fatty acid. The oil is used as apurgative and antibiotic in medicine and as an illuminant. In industries, castor oil is used for making cosmetics, soaps, plastics, resins, dyes, paints and lubricants [1, 3] while the cake is widely used as as an ingredient for compounding livestock feeds. Castor oil is also used in food industry as cooking oil, salad dressing and for production of mayonnaise and margarine while its technical uses include chalking compounds, core oils, disinfectants, electrical insulation, insecticide, oiled fabrics, painting and protective coatings [3]. There are three major means of recovering oil from oil-bearing materials which include wet extraction, mechanical extraction and solvent extraction. The wet extraction process is otherwise known as hot water or steam extraction. It is the oldest method of oil extraction used traditionally by women in rural communities for processing varieties of oil-bearing materials. Olaoye [4], Alonge and Olaniyan [5] and pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1144 Innovations (15th – 17th April 2008), Benin City, Nigeria Addaquay [6] used this method for shea butter extraction. The same method was also used for groundnut oil [7] and thevetial oil [8] extraction. Mechanical extraction or simply expression is the process of mechanically squeezing and pressing liquid containing solids in order to extract oils using oil extraction equipment such as hydraulic presses or screw expellers. The mechanical expression system is the most widely accepted method of oil extraction worldwide [9]. This method has been used for groundnut oil extraction [10], conophor oil extraction [11], soybean oil extraction [12] and shea butter extraction [13, 14]. Solvent extraction or simply chemical extraction, on the other hand, is the recovery of oil from oil-bearing materials with the aid of solvents while the process is carried out in equipment known as a Sohxlet extractor. The mechanical expression method has gained a worldwide popularity and acceptance in modern vegetable oil industry. Therefore, the objective of this study is to investigate the relevant process conditions affecting the yield and quality of oil mechanically expressed from castor seeds. Such information should elucidate the problems of castor oil expression and enable the development of process line for castor oil extraction mill. 2. 2.1.

Materials and Methods Mechanical Expression Rig As shown in Figure 1, the mechanical expression rig consists of two parts: (i) the California Bearing Ratio (CBR) Universal Testing Machine (UTM); and (ii) a piston-cylinder rig which was designed and fabricated for this experiment. This particular UTM is of a 20 kN capacity. The vital parts include: graduated scale, upper cylinder, upper fixed spindle, loading plate, lower spindle, lower cylinder, control mechanism, drive wheel control, stainless steel suspension and gear housing. The piston-cylinder assembly is made up of four major components: compression piston, press cage cylinder, press cage cylinder guide, supporting platform and oil collector. The compression piston serves as the pressing plunger that distributes pressure from the CBR-UTM evenly on the oilseed sample in the press cage cylinder. In operation, a heat sensor (thermocouple probe) is inserted into the oilseed sample (press cake) through a hole drilled on the side of the press cage cylinder 70 mm height from the base. 2.2.

Mechanical Expression Experiments Castor nuts were obtained from neighboring villages in Ilorin environs. The nuts were dried to a moisture content of about 5-6 % (db), shelled and winnowed to obtain clean castor seeds. The moisture content of the seed was obtained by oven-drying 100 g samples at 130 0C for 6 h as recommended for oilseeds [15] and used by Ajibola et al [16] and Tunde-Akintunde [17]. The experiment was carried out using a 33 factorial experiment under Completely Randomized Design (CRD). The process conditions involved three particle sizes (unshelled nut, whole seed and coarsely ground particles}, three heating temperatures (30, 60 and 90 0C) and three pressing time (8, 10 and 12 min). The coarse particle was obtained by grinding clean seeds using a plate mill until it passed a 3.35 mm laboratory test sieve [18]. A laboratory oven was used for heat-treating the castor seed samples though the selected temperatures for 30 min prior to oil expression. This range of temperature was chosen based on literature review and preliminary laboratory experiments. 100 g samples of coarsely ground seeds were weighed, heated in the oven for 30, 60 and 90 0C for 30 min and expressed for 8, 10 and 12 min using the mechanical expression rig in Figure 1. The same procedure was repeated for whole seed and unshelled nut samples with each experiment being performed in three replicates making a total of 81 experimental trials that were carried out. Oil yield, OY in %, was estimated as the ratio of the weights difference between unexpressed and expressed samples to the weight of unexpressed sample. It was mathematically expressed [19] as:

OY 100

WUS  WES WUS

………………….

(1)

where WUS and WES are weight of unexpressed sample and weight of expressed sample respectively in g. Oil extraction efficiency, OE in %, was mathematically expressed as: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1145 Innovations (15th – 17th April 2008), Benin City, Nigeria OE 100

WUS  WES xWUS

…………. ……

(2)

where x is oil content of castor seed (0.55 or 55 %). The force applied for extraction was obtained from the gauge of the mechanical expression rig and the extraction pressure was calculated by dividing the force applied by the cross-sectional area of the press cage cylinder of the rig. Samples of the oil expressed at different heating temperatures were subjected to physicochemical analysis to determine the quality attributes using the method of AOAC [20]. The quality criteria determined are sapoification value {SV}, rancidity index (RI), acid value (AV), moisture content (MC), specific gravity (SG), free fatty acid (FFA), colour intensity (CI), peroxide value (PV) and ester value (EV).

Figure 1. Mechanical expression rig: A – graduated scale; B – upper cylinder; C – upper fixed spindle; D – compression piston; E – press cage cylinder; F – thermocouple probe; G – oilseed cake; H – press cage cylinder guide; I – supporting platform; J – drainage channel; K – wire mesh; L – oil collectors; M – expressed oil; N – loading plate; O – lower spindle; P – lower cylinder; Q – control mechanism; R – drive wheel control; S – stainless steel suspension; T – gear housing Data obtained from the experiments for measured output (oil yield, extraction efficiency and extraction pressure) were statistically analyzed for Analysis of Variance (ANOVA) and Duncan’s Multiple Range Test (DMRT) using GENSTAT statistical package. 3.

Results and Discussion The result of statistical Analysis of Variance (ANOVA) of experimental data (summarized in Table 1) shows that the process conditions and their interactions were significant on the measured output at 0.05 level of significance However, only pressing time had significant effect on extraction pressure. This showed that particle size, heating temperature and pressing time and their combinations had influence on oil yield, extraction efficiency and extraction pressure during the oil expression process. Table 1. Analysis of variance (ANOVA) of the effects of process conditions (PC) on measured output: S particle size; T - heating temperature; P - pressing time; OY - oil yield; EE - extraction efficiency; EP extraction pressure PC DF Fr Pr > Fr OY EE EP S 2 349.40 323.79 0.46 7, no stiffly stable process was found. The graphs below show the root loci of the method in (1.8). Table 5 shows the interval of absolute stability of the methods for a fixed value of k < 6. The 3D-Plot in MATHEMATICA is use to determine the range of t and z for which the methods in (1.8, 1.9,1.10) are zero stable. Plotting r j against t and z shows the range t and z for which the methods in (1.8, 1.9,1.10) are zero stable, see figure 8, figure 9, figure 10, figure 11, figure 12, figure 13 and figure 14 below.

ÈÈ rj

5 4 3 2 1

z

0 -10

0

10

20

30

Figure 1: Root Locus for k  1

ÈÈ rj

2.5 2 1.5 1 0.5 0 -10

z 0

10

20

30

Figure 2: Root Locus for k  2

ÈÈ rj

1 .4 1 .2 1 0 .8 0 .6 0 .4 0 .2

Z

0 -1 0

0

10

20

30

Figure1: Root Locus for k  3 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1230 Innovations (15th – 17th April 2008), Benin City, Nigeria

ÈÈ rj

1.4 1.2 1 0.8 0.6 0.4 0.2

Z

0 - 10

-5

0

5

10

Figure 2: Root Locus for k  4

ÈÈ rj

1.75 1.5 1.25 1 0.75 0.5 0.25 z

0 -10

-5

0

5

10

Figure 5: Root Locus for k  5

ÈÈ rj

2 1.5 1 0.5 0 -60

z -40

-20

0

20

Figure 6: Root Locus for k  6

ÈÈ rj

2 1.5

1 0.5

0

z -25

0

25

50

75

100

125

Figure 7: Root Locus for k  7

Figure 8: 3D-Plot for k = 1

Figure 9: 3D-Plot for k = 2

Figure 10: 3D-Plot for k = 3

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2nd International Conference On Engineering Research & Development: 1231 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 11: 3D-Plot for k = 4

Figure 12: 3D-Plot for k = 5

Figure 13: 3D-Plot for k = 6

*Figure 14: 3D-Plot for k = 7 Table 4: The interval of absolute stability, order and error constant of the methods in (1.8, 1.9, 1.11). k

H H LÜH H LÜH H LÜH H LÜH H LÜH H LÜH H

1

0

2

1

3

2

4

3

5

4

6

5

7

6

HLHL JN HJLN HL HL HL LHL L L L L L L L

In t e r v a l o f A b s o l u t e S t a b i l i t y O rd e r p O rd e r p 1 1 .8 o f H S D C L M M 1 .8 , 1 .9 , 1 .1 0 1 .9

t

O rd er

p11

1 .1 0

E r r o r C o n s t a n t E rr o r C o n s t a n t E r ro r C o n s t a n t o f 1 .8 o f 1 .9 o f 1 .1 0

5. 5443 , ¥

4

3

2

- 23 35040

11 1152

1 12

, 0

7. 24 , ¥

5

4

3

121 710280

71 23040

25 384

- ¥

,0

8. 5 , ¥

6

5

4

2631 42062440

109 76800

157 2880

- ¥

,0

8. 4 , ¥

7

6

5

8103 289447340

101 129024

243 5120

8

7

6

- 758525 53141122356

6971 14450688

40997 967680

9

8

7

- 2006815 251243560316

1191389 3715891200

1191619 30965760

10

9

8

, 0

- ¥

- ¥

- ¥

,0

10. 48, ¥

- ¥

, 0

11. 3 , ¥

u n s t a b l e S e e fi g . 4 . 7

-

-

-

-

-

-

The interval of absolute stability of the methods reveal that as the step number k increases the interval of absolute stability of the method in (1.8) decreases. Table 5: The range of t for which the method in (1.8) is zero stable k

HLHLH L 8 H LÜH L< 8 H L< 8 H LÜH LÜH L< 8 H LÜH LÜH L< 8 H LÜH LÜH L< 8 H LÜH LÜH L< H L

T h e r a n g e o f t fo r w h i c h t h e m e t h o d i n is z e ro s t a b le . 1 2 3 4 5 6 7

t

: t e

t

t

: t

t

t

e

: t e

-

t

, 0

¥

- 1 ,

, - 1 . 3 4

- ¥

: t e

-

: t e

- ¥

, - 1

: t

e

-

¥

, - 1

1 .9

+

1 . 1 0

0 , ¥

0 , 3 4 1 8 5

u n stab le

+

2 . 8 2 2 5 2

0 , 4 . 2 5 2

5 0 , - 1 . 1 6 5

1 . 8

2 , 5 . 1 1 8 3 , 6

3 . 4 1 8 7 , ¥

4 . 25 3 ,

¥

5 .1 1 9 , 5 0

6 .1 , ¥

S e e fi g . 4 . 7

6. Numerical Experiment

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2nd International Conference On Engineering Research & Development: 1232 Innovations (15th – 17th April 2008), Benin City, Nigeria In this section we will test and compare the derived in this paper with those proposed in Enright [2] and that of Ode15s code of Matlab in Higham et al [17]. We use the methods in (1.8, 1.9, 1.10) to solve the nonlinear chemical problem of Robertson [8]  y ( x)  0.04 y ( x)  10 y ( x) y ( x) (6.1)  / 1

4

1

/ 2

2

3

4

7 2  y ( x)  0.04 y1 ( x)  10 y2 ( x) y3 ( x)  3  10 y2 ( x) ,  / 7 2  y3 ( x)  3  10 y 2 ( x)  x  [0, 3], y (0)  0 1 1T , 

with h=0.0001, and as in Enright (1974) and Higham et al (2000), as a test case for the methods in (1.8, 1.9, 1.10). To solve (6.1), set up the formulas in (1.8, 1.4, and 1.5) from tables (2.2), (3.2), and (4.2) respectively. These are 1 80 4h * 29h 17 h 2 / , y  y  y  f  f  f n 1

73

n

73

n  12

73

n  32

73

n 1

146

n 1

p=4

(6.2) 2

y n 1  y n  2

h 7 f n  5 f n 1   h f n/1 , 24 12

y n  3  y n 1  2

h  f n  5 f n 1  , 8

p = 3 (6.3) p=2

(6.4)

Substituting (6.3) and (6.4) into (6.2) and applying the resulting scheme to the above problem (6.1) requires the need to solve the system of nonlinear equation for y n 1 . The implicit system of equations in y n 1 of (6.2) is resolved by applying the Newton Raphson iterative scheme in (1.3), see Enright [2], Fatunla [9], Lambert [6, 7], Otunta et al [14], and Ikhile and Okuonghae [3]. The starting value for (1.8) is obtained using (1.4). The results in the graphs below of the second component of the initial value problems compares with that from Ode15s code in Matlab discussed in Higham et al [17]. The plot is shown in figure 1.

Figure 1: The plot of numerical solutions of y 2 ( x) of the nonlinear stiff IVPs (6.1). Conclusion Finally, we have Considered SSSDCLMM (1.8) for the numerical solution of a stiff differential system. The methods are found to be stiffly stable for k  6 . For k > 7, the methods are found to be unstable. The graph of the numerical results which coincides indicates that SSSDCLMM is of comparable performance with the state-of–the-art ode15s code from Matlab ODE suite in Higham et al [17]. References [1] [2] [3]

C. W. Gear, The automatic Integration of Stiff Ordinary Differential Equations, Proc. IFIP Congress, North-Holland. Amsterdam. (1968), Vol. 1, pp. 187-194. W. H. Enright, Second Derivative Method for Stiff Ordinary Differential Equations SIAM. J. Numerical Analysis (1974), Vol. 1, No. 2. pp. 321 – 331. M. N. O Ikhile, and R. I. Okuonghae Stiffly Stable Continuous Extension of Second Derivative Linear Multistep Methods With an Off-step Point for the Numerical Integration of Stiff Ordinary pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1233 Innovations (15th – 17th April 2008), Benin City, Nigeria

[4] [5] [6] [7] [8] [9] [10] [11] [12] [13]

[14]

[15] [16] [17]

Differential Equations. Journal of the Nigeria Association of Mathematical Physics (2007). Vol. 11 pp. 175-190. P. Onumanyi, U. W. Sirisena, and D. O. Awoyemi A new Family of Predictor-Corrector Methods Spectrum Journal, (1996). Vol. 3, No. 1 & 2. C. Arevalo, C. Fuherer, and M. Seva, A Collocation Formulation of Multistep Methods for Variable Step-Size Extensions. Appl. Numer. Math. (2002), Vol. 42, pp. 5-16. J. D. Lambert, Computational Methods in Ordinary Differential Equations; John Wiley and Sons, New York., 1973 J. D. Lambert, Numerical Methods for Ordinary Differential Equations; John Wiley and Sons, New York., 1991. Robertson’s Example for Stiff Differential Equations. NEC Research Institute, Research Index (citeseer), 1995, 7 pp. in http://citeseer.nj.nec.com/67303.html S. O. Fatunla, Numerical Methods for initial Value Problems in Ordinary Differential equations, Academics Press, Inc. 1988. J. C. Butcher, A Modified Multistep method for the Numerical Integration of ODEs. J. Assoc. Comp. Mach. 12, (1965). 124-135. C. W. Gear, Hybrid Methods for IVPs in ODEs. SIAM. J. Numer. Anal. 2 (1965), 69-86. W. B. Gragg and H. T. Setter, Generalized Multistep Predictor –Corrector Methods. J. Assoc. Comput. Mach. 11, (1964), pp. 188 -209. M. N. O. Ikhile, and R. I. Okuonghae; Some Continuous Linear Multistep Methods for Stiff Initial Value Problems in Ordinary Differential Equations. Nigeria Journal of Applied Sciences. (Accepted for Publication). F. O. Otunta, M. N. O Ikhile and R. I. Okuonghae, Second Derivative Continuous Linear Multistep Methods for the Numerical Integration of Stiff Ordinary Differential Equations. Journal of the Nigeria Association of Mathematical Physics (2007); Vol. 11, pp. 175-190. G. Dahlquist, Convergence and Stability in the Numerical Integration of ODEs. Math. Scand; 4 (1956), pp. 33 – 53. G. Dahlquist, A Special Stability Problem for Linear Multistep Methods. BIT,3 (1963), pp. 27- 43. J. D. Higham and J. N. Higham, Matlab Guide. SIAM. (2000), Philadelphia.

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2nd International Conference On Engineering Research & Development: 1234 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08123) System Potential-Based Productivity Evaluation Model C.O. Anyaeche (1) and A. E. Oluleye(2) Department of Industrial and Production Engineering University of Ibadan, Ibadan, Nigeria. [email protected] and [email protected] (1,2)

Abstract Productivity evaluation if based on historical record, rather than the system’s potential, does not fully account for the maximum exploitation of the system. This work uses an optimization technique, the Linear Program, to establish the system’s potential; and then develops the Potential-based Productivity Evaluation model. Applying this model in an example case gave productivity as 0.98, price recovery 1.07 and profitability 1.06; while the historical approach gave 2.81, 0.34 and 0.97 respectively. A comparison shows 187% over-reporting, 65% under-reporting and 8% lag respectively. These would affect the firm’s decisions differently. The model can be used for strategic planning. Keywords: Productivity, Potential, Resource reallocation, Liner Program, optimization 1. Introduction Productivity evaluation is often carried out with historical data serving as a base without the necessary consideration for the system potential. This approach is akin to driving while using the rear mirror as the guide or playing chess while watching the score board [8]. Even benchmarking is usually carried out with the accepted standard, which if within the same industry is internal but generic if inter-industry [2, 3]. However, these approaches are without reference to the actual potential of the system which varies from time to time [1, 2]. Even evaluation done with different foci, often give different; and sometimes contradictory results [5, 7]. This work is an attempt to address this gap in knowledge. The work would develop a framework for determining the system’s potential and use the same as the baseline for the evaluation of the system. Productivity involves a twin approach of optimising the use of resources and enhancing the value of the output [4]. In this work, we focus on resource optimization. For a given level of input, an improvement in the efficiency of the use of the resources should result in higher output and a corresponding drop in the unit cost of outputs. This drop in unit cost gives an asymptotic relationship between the unit cost and volume of production. This work considers a scenario where a given level of inputs is available and seeks out the optimal product mix and the maximum productivity. A two-phase approach to productivity and profitability evaluation presented by [1] combines the Linear Program (LP) and the APC model concepts; namely the LP-APC model. The model does not address the performance of outputs. The Input and output-based productivity evaluation model (IOP) [2] addresses the evaluation of both the inputs and the outputs but not with reference to the system’s potential. This work presents a model that evaluates productivity with the system’s potential as the standard, named the LP-IOP model. It combines the concepts of Linear Program (LP), which is an optimization technique; and the Input and Output-based productivity evaluation model [2]. The LP is used to establish the potential, which is subsequently employed as the base in the IOP productivity analysis. 2.0 Conceptual Framework 2.1. Linear Programming: Many organisations have used the Linear Program (LP) technique to determine the optimal combination of inputs to maximise profits or benefits. Indeed, of all operations research methods, the LP appears to be the pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1235 Innovations (15th – 17th April 2008), Benin City, Nigeria most commonly used by managers [9]. However, it has usually been used as a stand-alone method with the focus on improving profit levels. The general LP model can be viewed as a resource allocation problem [6, 9, 12] and the terms are defined thus: Z = Activities’ contribution to profit. n = no of activities. xj = level of activity j m = no of available resources bi = maximum availability of resource i aij = an amount of resource i consumed by activity j . cj = contribution per unit of activity j In the standard form, the LP model is stated [6, 12] as: n

Maximize

Z =

c x

j j

j1

n

Subject to:

a x

ij j

> 0, where xj > 0

j1

The LP model seeks the best allocation of limited resources to specific economic activities [1, 9]. In a product-mix LP model, the solution gives the optimum product mix and the maximized (minimized) objective function. Also a sensitivity analysis is carried out to determine the limiting factors, the slacks and surpluses, the opportunity costs, the shadow prices and the feasible range, should additional resources be available. To optimize the use of the resources available in the system, a reallocation is carried out from the surplus to the limiting factors to ensure that the system’s potential is exploited [2, 7]. This work uses resource reallocation to exploit the systems’ resources maximally. 2.2 IOP Model This work uses the Input and output-based (IOP) model [3], for its productivity evaluation, with a focus on the following performance measures: i. Dynamic productivity (Pd) ii. Dynamic price recovery (Pr) iii. Dynamic profitability (Pf) These measures are for both the inputs and the outputs and the details are in [2, 5, 11, and 13]. 3.0. Methodology 3.1 LP-IOP Model: The work carries out productivity evaluation in two phases. First it carries out resource optimization and subsequently the productivity evaluation. In the optimization process, the LP is setup using the activity matrix and then solved using the Quantitative Systems for Business plus (QSB+) software. A sensitivity analysis is also carried out to determine the surpluses and the slack, as well as the feasible range. The reallocation from surpluses to tight resources (here referred to as limiting factors), then gives other scenarios of LP formulations. The LP evaluation is carried out at each stage after resource reallocation to highlight surplus resources for subsequent reallocation. This approach should continuously reveal the performance gap that needs to be bridged to ensure that the optimum performance of the system is exploited. Ordinarily, the common practice may not reveal this. In planning, the LP solution gives the profile of the resources required.

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2nd International Conference On Engineering Research & Development: 1236 Innovations (15th – 17th April 2008), Benin City, Nigeria The reallocation and the evaluation are carried out until no further improvement is achieved thus establishing the threshold values. The final LP solution gives the optimal values, and the thresholds, which in this application gives the system’s potential. 3.2 Resource Reallocation Procedure Here we summarize the resource reallocation steps: Step 1: Set-up and Solve the LP. Step 2: Determine the maximum surplus resource available. Step 3: Obtain the feasible range of the current resource allocation levels (the LP1 solution). Step 4: Determine the minimum and maximum ranges for each of the resources (from the sensitivity analysis of the current resource allocation level). Step 5: Ensure that the result achieved in the current resource allocation level is not lost; by making the current solution the minimum level of resource. Step 6: Solve the new LP and carryout sensitivity analysis. Step 7: Compare with the previous result. Step 8: Repeat steps 1 to 7 until two consecutive results from step 7 are the same. In the second phase, the LP threshold values are used to carry out the productivity analysis. The Excel software is used for the productivity analysis, and the model developed is named the Linear Program-based Productivity Evaluation (LP-IOP) model. 3.3 Model Application Data Collection Data were collected from a beverage firm in Nigeria and used to demonstrate the utility of the model. Collected data are as in Tables 1, 2 and 3, which give the unit contributions, resource allocation plan and average consumption cost of input respectively.

Table 1: Output contributions (Naira).

x1 x2 x3 x4

Qty 256.00 2.00 16.00 39.00

s/price 36,193.19 48,690.00 35,641.23 19,756.26

C/price 31,300.16 43,958.68 31,388.40 15,005.60

contribution 4,893.02 4,731.32 4,252.78 4,750.66

Table 2: Resource allocation plan. INPUT Labour

Resource Cost in Naira 1

310,697.65

2

7,155,399.61

Energy

3

159,637.49

Capital

4

335,546.55

Overheads

5

99,679.76

Misc

6

20,470.80

Materials

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2nd International Conference On Engineering Research & Development: 1237 Innovations (15th – 17th April 2008), Benin City, Nigeria Total

8,081,431.86

Table 3: Average consumption cost of input in Naira. Resource x1 1 1,192.31 2 28,179.12 3 523.44 4 1,110.94 5 230.72 6 63.64

x2 5,538.72 13,298.92 3,685.00 12,145.00 8,127.33 1,163.72

x3 1,020.46 27,085.3 1,096.88 1,336.87 703.48 145.40

x4 528.54 11,833.91 578.97 1,318.46 686.04 59.68

3. 4 LP Formulation In formulating the LP, we use the notations x1, x2, x3 and x4 to stand for outputs 1, 2, 3 and 4 respectively, while Z the objective function, as the total contribution to profit. Using the data in Tables 1, 2 and 3, we give the LP 1 as: Max Z = 4,893.02 x1 + 4,731.32 x2 +4,252.78 x3 + 4,750.66 x4 Subject to: 1,192.31 x1 + 5,538.72 x2 + 1,020.46 x3 + 528.54 x4 ≤ 310,697.65 …………………..….…… .(1) 28,179.12 x1 + 13,298.92x2 + 27,085.3 x3 + 11,833.91x4 ≤ 7,155,399.61…….……….… … (2) 523.44x1 + 3,685.00 x2 + 1,096.88 x3 + 578.97 x4 ≤ 159,637.49 …………………….……… (3) 1,110.94 x1 + 12,145.00 x2 + 1,336.87 x3 + 1,318.46 x4 ≤ 335,546.55…. ……….…….. .. (4) 230.72 x1 + 8,127.33 x2 + 703.48 x3 + 686.04 x4 ≤ 99,679.76. …. …... ……………..…… (5) 63.64 x1 + 1,163.72 x2 + 145.46 x3 + 59.68 x4 ≤ 20,470.8 …. … ... ……….…..…...... (6) 31,300.16 x1 + 43958.68 x2 + 31388.40 x3 + 15,005.6 x4 ≤ 8,081,431.86 …….…..…….… (7) x1  1 …… …………….… ...………….… (8) x2  1 …… …….. .… …………..………... (9) x3  1…… …….. .… ………….………... (10) x4  1 …… …… …. ………….……..…. (11) Following the procedure stated in section 3.2, a reallocation of resources is carried out and the LP formulated and solved until two consecutive results are the same. 4.0 Results and Discussions The result of LP 1 is given in Table 4; while the sensitivity analysis result is in Table 5. The result of the last LP is given in Table 6. Table 4: Summarized result for LP 1 |------------------------------------------------------------------------------| | | | |Opportunity| Objective | Minimum | Maximum | |Number | Variable | Solution | Cost |Coefficient|Obj. Coeff.|Obj. Coeff.| |-------+----------+-----------+-----------+-----------+-----------+-----------| | 1 | X1 | +232.00510| 0| +4893.0200| +4002.9263| +11312.358| | 2 | X2 | +1.0000000| 0| +4731.3198| - Infinity| +39081.961| | 3 | X3 | +1.0000000| 0| +4252.7798| - Infinity| +5554.4858| | 4 | X4 | +48.785248| 0| +4750.6602| +2232.4038| +5807.0205| |------------------------------------------------------------------------------| | Maximized OBJ = 1375952 | |------------------------------------------------------------------------------| pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1238 Innovations (15th – 17th April 2008), Benin City, Nigeria

Table 5: Sensitivity analysis of LP 1 |------------------------------------------------------------------------------| |Constr- | | | Shadow | Slack or | Minimum | Maximum | |aint no | Status | RHS | Price | Surplus | RHS | RHS | |-------+---------+------------+-----------+-----------+-----------+-----------| | 1 | Loose | carbohydrate > lipase > protease > control.

[ For the detailed document go to page 1622]

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2nd International Conference On Engineering Research & Development: 1324 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08243) ASSESSMENT OF HYDRAULIC PERFORMANCES OF DRAINAGE CHANNELS IN UNAAB CAMPUS

Bolaji G. A. Department of Civil Enginering, University of Agriculture, Abeokuta, NIGERIA Introduction Drainage channels are usually provided in urban areas to convey excess runoff generated from storm water away into nearby natural drainage systems. Urbanization increases the volume of runoff that can be generated from a storm event because, the ground surface through which water percolates into the ground has become sealed in one form or another. In UNAAB campus it was observed that drainage channels that were originally designed to carry the runoff could not perform efficiently as they used to do, therefore a study was carried out to investigate the causes of the problem. Materials and methods Map of the campus was obtained from the physical planning unit and the existing buildings, car parks, grassed areas, drainage network, etc were located on it. The campus was divided into four sub-catchments but two were chosen for the study. The runoff characteristics of the sub-catchments were computed based on the data obtained from rainfallintensity-duration curves for Abeokuta and runoff coefficient values obtained from literature. The reduced level values of the channel bottom were obtained from leveling survey carried out. The channels’ longitudinal and cross sections were plotted based on the reduced level values. The channels were categorized into primary and secondary channels to represent the volume of water that they can carry at a particular storm event. The channel parameters that influence flow in the channels such as velocity, hydraulic radius, area of cross-section etc were used to determine the hydraulic efficiency of the channels. Froude number, type of flow and water surface profiles at certain stretches was determined and they were used to describe the condition of flow and flow characteristics for the stretches. Graphical plots of the channel longitudinal sections and water surface profiles were also used to check whether changes in channel properties could eliminate the problems of siltation. Results The results obtained from the study indicated that at many sections tested hydraulically, the flow were usually under sub-critical conditions. At sections where flow was conducted beyond 150m, reduced depth of flow occurred and led to formation of hydraulic jump. Energy changes that occurred during flow influenced the hydraulic performances of the channels. Discussions Conclusion The study took account of the amount of runoff, channel characteristics and hydraulic properties of the channel. The conditions of flow were considered to be affected by varying channel characteristics and volume of runoff. The change flows from under critical to sub-critical conditions especially within short distances identified were responsible for siltation experienced in the channels. Recommendations The study recommended adequate management practices for the lawns and regular maintenance of the channels. It was also recommended that the slope of channel bottom be changed in some sections. References Chow T. V. 1964: Handbook of applied hydrology. Section 14, pp 1-50. McGraw-Hill Books. New York. Dianz, M. 1973: Tests of new methods of water discharge measurement in Params River. Water resources bulletin, pp 971-976. Leopold, L. B. 1968: Hydrology for urban land planning. A guide book on the hydrologic effects of urban land use. USGS. 18pp.

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2nd International Conference On Engineering Research & Development: 1325 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08235) Gaseous emission attributed pollution in the oil producing communities in Nigeria

F.A. Gabriel (VEAN Associates Nigeria Ltd, Nigeria e-mail: [email protected]) and A.J. Akpan (Akwa Ibom /state University of Technology, (AKUTECH), Nigeria 1.00 BACKGROUND: The Oil producing Communities in Nigeria is presently in the Niger Delta ecological region -which comprise of Nine States that are largely coastal and low-lying (usually a feet above sea level), the region because of its geographical location experiences high rainfall, with high relative humanity and average temperature. Climate conditions in the region favour agriculture, explaining the reasons for most inhabitants are others who are peasant farmers, and fishermen. Apart from farming, there are others who are involved in trading and small scale industrial activities Although petroleum resources sustain the Nigerian economy, industrial activities in the sector have been known to be associated with substantial environmental degradation and social crises, posing a potential threat to sustainable development in the Niger Delta, where the bulk of the country’s petroleum resources are found. Although most of the negative environmental consequences of oil industry activities are localized and more intense in the areas of primary activities, some of the effects have transboundary implications (Orubu et al; 2004). For example, gas flaring which is a common feature of the Nigerian petroleum industry has been known to be a factor in the problem of global warming (World Bank, 1995).In the same vain, mangrove swamp and the rain forest destruction as a result of oil industry activities can have long-term consequences for both ecological and climate balances .The Niger Delta is located in the Southern part of Nigeria bordering the Atlantic Ocean. The delta is poorly serviced by roads and is made up of meandering creeks that are highly silted up along floodplains. The Niger Delta is one of the world’s largest wetlands covering an area of about 70,000 square kilometers the region is noted for a number of characteristics ecological zones which range barriers, swamps and seasonal swamps forests, saline mangroves and fresh water mangrove. The Niger Delta environment has been reported to be highly diverse and sensitive(ERML,1997), being the home of the largest stands of mangrove in Africa (over 1 million ha) and the fourth largest in the world ( Spalding et al, 1997; Ukpong ,2007), it is of both regional and global importance(Moffat and Linden, 1995).The Delta is also rich in fishery resources; it provide breeding grounds for various species of finfish, prawns and as habitats for crabs and mollusk (IPIECA,1993). Development of oilfield infrastructure in the mangrove areas of the Niger Delta is often preced by dredging and / or vegetation clearance to create navigable accesses (Ohimain,2004; Akpan,2007).During dredging, the soil, sediment and vegetation along the right of way (ROW) of the proposed site are removed and typically disposed over bank, and in most cases upon fringing mangroves, and then abandoned. The abandonment of the resulting dredged material has caused a number of impacts including altered topography and hydrology, acidification and water contamination, which has resulted in vegetation damage and fish kills ( Ohimain,2004). See figures 1 and 2 as: Location map and the ecological zonation of the Niger Delta based on vegetation type respectively. Pollution is defined in this presentation as the contamination of any part of soils ecosytem, surface and underground water bodies, and air composition as a result of oil and gaseous flaring, oil spillage, pipe-line leakage, deliberate and wanton destruction of Offshore, Onshore drilling platforms, corked well sites by nefarious militant groups the oil producing Communities.(Thereby making the holistic environmental components either unhealthy or unsafe for biogeocoenosis habitats. The committee on pollution of United States’ National Research Council defined pollution as an undesirable change in the physical, chemical, biological characteristics of our air, land and water that may or will harmfully affect life or that of other pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1326 Innovations (15th – 17th April 2008), Benin City, Nigeria desirable species, our industrial processes, living conditions, cultural assets or that may or will waste or deteriorate our raw material resources (USNRC,1965; Oluwade,1998;Udoessien:1997 and 2003; Miller,2001; Ndukwe,2000). Pollution is a disorder within an environment and is a by-product of energy conversion and the use of resources. It is a contamination, defilement, a mischief, a perturbation and reduction in the value of an object or thing. Pollution could be harmful to the entire environment and to the health and well being of all living things. Pollutants when released in the water, soil, and air can find their way into living tissue and organs of living plants and animals or into the human body as a result of breathing, eating, or drinking; as well as extracting mineral resources from the environment. Thus, pollution, however defined, depends on which components of the earth that is contaminated. It may be the air, water, land, or even the vegetation that is affected by pollution (Anijah-obi,2001).Pollutant is defined as any substance that creates an adverse human health or environmental effect, which is introduce into the environment. Pollution is the introduction or the release of pollutant into the environment (air, water, and land). Pollution prevention is the methods and techniques for reducing, or eliminating pollution including source reduction, reuse, recycling, reclamation, or modification of operating practices to reduce the quantity and / or toxicity of air emission, solid waste generation and waste water discharges(Warren and Robert,1999).This similar to the definition of pollution prevention developed by the American Petroleum Institution(API), which state’s that pollution prevention is a multi media concept that reduces or eliminates discharges to air, water or land. Pollution prevention includes the development of more environmentally acceptable products, changes in processes and practices, source reduction, beneficial use, and environmentally sound recycling (Warren and Robert, 1993). Various geotechnical investigations in the field and laboratory test and analyses have been carried out into the effects of petroleum hydrocarbon and natural gases on soils properties in general and soil microbial activities in particular, which started as far as the beginning of the 19th Century.The opion that has prevailed among Scientists since 1870’s is called the biogenic theory which, “holds that biological debris buried in sediments decays into soil and natural gas in the long course of time and that this petroleum then becomes concentrated in the pore space of sedimentary rocks in the uppermost layers of the (Earth’s ) crust.” This process the produces petroleum, whose main components are hydrocarbons- that is hydrogen and carbon. The National Acacdemy of Sciences proceeding states, “the genesis of hydrocarbons and the origin of petroleum and natural oil and gas must occur at depths that are well into the mantle of the Earth and not at the shallower depths generally accepted (NAS,2002).Physist Thomas Gold in a controversial theories explains in: “the myth of Fossil Fuels” from the abiogenic theory which holds that, “hydrocarbons were a components of the material that formed the Earth, through accretion of solids,some 4.5 billion years ago and the elements of petroleum have been in the Earth since the earth’s formation(Awake,2003). Oil and gas pollution from Offshore and Onshore coastal installations contribute significantly to ecological degradation, destruction and environmental devastation.As a result of the persistent gas flaring activities by Shell Petroleum Development Company (SPDC) and others multinational oil and gas companies,Nigeria wears the unflattering badge as the World’s leader in natural gas flaring (gaseous emission into the transboundary and global atmosphere). According to the the World Bank (2001) 87% of all associated gas is flared by Shell and her cohorts. The World Bank records highlight the fact that the Niger Delta atmosphere receives 80 Billion cubic feet of gaseos emission from Shell’ s (Obnoxious) flaring activities.This gives SPDC the dubious distinction of being one of the World’ chief contributors of global warming (Okonta and Douglas, 2001). The Akwa Ibom State Environmental Protectation Agency (AKSEPA,1986) surveys of several villages in its oil producing districts provide a chilling account of Shell’s air pollution atrocities: “Acid rains according to the people of Iko has been corroding the zinc and non-zinc corrugated roofing of their houses and also harming plants and animals life. Studies have shown the abililty of sulphuric acid produced when SO2 react with the atmospheric water vapour, to damage soil, buildings and other structures. The damage is especially obvious where large amounts of sulphur- bearing oils are flared. There is also evidence that sulphuric acid mists cause damage to plants leaves, and that sulphur particles, combined with other lethal gases in the atmosphere, have been responsible foe extensive damage of forests in the areas near large combustion point sources of gaseous emission/ flaring.The adverse impact ofacid rain on rivers and surface waters is no less significant. Fish and in particular their eggs and juvenile forms are especially susceptible to increase inacidity, decresing in population or dying off completely. AKSEPA has investigated other Shell pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1327 Innovations (15th – 17th April 2008), Benin City, Nigeria installations including it Utapete flowe station. There they found crop harves failures and vanishing fish populations in surrounding streams and creeks. They also found life expectancy, already a Low at 54 years forr Nigeria, indecline as the people in this village battles respiratory ailments attributed to polluted air that they breathed on daily basis (AKSEPA,1986). Hydrocarbon pollution of environmental components: Soils ecosystems, surface and sub-surface; and underground water aquifers has been investigated by others: ( Auquo,1974; Udo,1998; Ukpong:1994,1995b,2000 and 2001; Gabriel,2004 and 2007). In this area of study, Iko Comuunity has previously been investigated by Udofia and Ikurekong (1998).As a result of biomass burning, dangerous gases which are detrimental to the quality of Iko Community and its environment were released into the atmosphere. These gases include carbon dioxide (CO2 ) and nitrogen oxides(NO) were emitted from the fire into the atmosphere. In addition, a large variety of gases and particulates are emitted including the product of imcomplete combustion of carbon compounds such as carbon monoxide (CO) metane (CH4 ), as wellas other hydrocarbons and other compounds containing nutrient elements such as nitric oxide(NO2 ), ammonia (NH2 ) and sulhpur oxides (SO2 ). Acid deposition also also as a result of biomass burning (including fuel wood combustion) in the tropical environment generally has raised some concern because of the associated pollution traced to biomass burning. The direct gaseous emission of organic acids from photo-chemical formation of formic and probably acetic acid in the fumes results inacid deposition on plants and soils either by rain or fog (wet deposition) or by aerosol and gases at the dry surface deposition (Udofia and Ikurekong,1998; Udotung, 2000; Udoessien,1997 and 2003; Gabriel,2004 and 2007). Indiscriminate disposal of solis waste, liquid and gaseous waste products alter the ecological balance and the dynamic equilibrium of human habitats (Rao,2004). Hence, Iko, a petroleum producing Community in Akwa Ibom State is certainly and was affected by the advers effect of oil and gas flaring (Ndukwe,2000).where the soil is polluted by hydrocarbon; the following are likely to occur: i) Soil micr-organisms would be destroyed. ii) Decomposition of organic matter would be slowed down or terminated. iii) The Soil would be deficient in nutrients such as:N, Ca, Mg, K, and Na. iv) Soil pores are blocked by hydrocarbon. The heavy metals example, lead (Pd) would accumulate in levels that could become toxic to organism (Ukpong,2001;Rao,2004, Gabriel,2004 and 2007). 1.10

INTRODUCTION TO THE ENVIRONMENT

The environment is defined as a surrounding, surrounding objects, regions or condition, example, circumstances of life, person or society; not only physical surrounding but also situation which arises from ones mental view of life or societal conscience and the general conception of its people. The environment refers to the components of the geosphere(land), hydrosphere (water), biosphere (living plants and animals) and the atmosphere (climate, weather and air) as commonly applied in the natural sciences (Environmental Matters:2005,2006 and 2007; UNITAR,2006; Odjugo,2000; Miller,2001). The environment is a reservoir or resources on which man is able to tap (extract) from nature, in order to sustain economic activities thereby assuring survival and human well being (Edward Elgar,2007. The environment according to Ukpong (2005) denotes the complex physical, chemical and biotic factors that act upon an organism or an ecological community and ultimately determines its form and survival. More precisely put, an environment is the sum total of all conditions that suurounds a man at any point on the earth surface. In other words, there is a Nigerian (Local, State and, Regional) environment, which are the (strategic) sum total of all conditions that surrounds the Nigerians and; to understand this sum total of all environmental conditions in the oil resources rich Communities in Niger Delta… either the course is because of curses? Hence,among the environmental factors man is exposed to the atmosphere and the related processes of weather and climate are of greatest importance. The present atmospheric conditions of gaseous emission attributed pollution in the Oil producing communities in the Niger delta ecological zone of Nigeria have developed since the discovery in 1957 of crude oil exploration and exploitation firstly at Oloibiro Community in the present Rivers State. Without the existence of so called greenhouse gases the most important ones are water vapour (H20) carbon dioxide (CO2), ozone (o3) nitrous (N2O) and methane(CH4). A large number of scientists from all over the pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1328 Innovations (15th – 17th April 2008), Benin City, Nigeria world assess our knowledge on natural and anthropogenic climate change since 1988 within the Intergovernmental Panel on Climate Change (IPCC,2007).In two substantial change, its impacts and mitigation in 1990 and 1995. the Third Assessment Report was expected in 2001 while the fourth Assessment Report in formed all government and the public at large about and formulated the following assertion, “the balance of evidence suggests a discernible human influence on global climate”. Observed and calculated patterns of global warming are this to be as severe warming signals for humankind.This hold true for the change in atmospheric ozone amount and vertical distribution, example a considerable depletion of the stratospheric ozone concentration in the troposphere on the other diminishing the stratospheric ozone layer. Dangerously increase ultraviolet radiation reacting to the Earth’s surface whereas additional tropospheric ozone layer enhance green house effect which also threatens human health, reduce agricultural yield and damage forests. These gaseous emission from oil and gas exploration and production sites in the Niger Delta region is among the fundamental changes in the spatial climate variability having impacted seriously on the natural ecosystem and human societies, including land use pattern, vegetation cover and agriculture, fisheries and shipping, air traffic, underground water management and soils, systemic human health, social welfare and environmental well being. All these depletion of natural resources are at the detriment of national wealth are the banes of developments which includes: Poverty, inequality, unemployment, traditional and cultural neglect/ communal marginalization, economics disempowerment of native folks; women and children, financial deprivation of mineral royalties accrued from foreign exchange earning, thus couple with high profile corruption and mismanagement of human capital and capabilities being misguided on misplaced environmental priorities owing to the constraint of incomplete scientific knowledge about the long term welfare implications of environmental degradation. These anti- developments are the causal effect of conflict among the geo political interest groups and, the deliberate tampering on the cork wells by nefarious militant entities at the (Ward levels ) local communities agitating on ecological synergies and energy crises in most of these oil and gas producing Communities of Nigeria. Since the Niger Delta ecological zone is the country’s economic and energy resources base.The region is the most active, and vibrant with quantum abiotic and biotic organisms as either producers or consumers., based on how they get food. Producers, sometimes called autotrophs (self feeders), make their own food from compounds obtained from their environment. On land, most producers are green plants. In fresh water and marine ecosystems, algae and plants are the major producers floating and drifting are phytoplankton, most of them microscopic. Only producers make their own food; all others organisms are consumers, which depend directly or indirectly on food provided by producers. Most producers capture Sunlight to make sugars(such as gluocose, C6 H12 O6 ) and other complex organic compounds from inorganic (abiotic) nutrients in the environment. This process is called Photosyntheis. Although hundreds of chemical changes take place during photosynthesis, the overall reaction can be summarized as follows: Carbon dioxide + Water+ Solar energy--- Glucose + Oxygen. Hence, the chemical equation is as thus: ( 6 CO2 + 6 H2O + solar energy --- C6 H12 O6 + 6 O2 ). All other organisms in an ecosystem are consumers or Heterotroghs (“ other feeders”), which get their energy and nutrients by feeding on other organisms or their remains ( Miller,2001). Both producers and consumers use the chemical energy stored in glucose and other organic compounds to fuel their life processes. In most cells, this energy is released by aerobic respiration, which uses oxygen to convert organic nutrients back into carbon dioxide and water. The net effect of hundreds of steps in this process is represented by the following reaction: Glucose+ Oxygen--- Carbon dioxide + Water + Energy ( C6 H12 O6 + 6O2--- 6CO2 + 6H2O + energy. Although the detailed steps differ, the net chemical change for aerobic respiration is the opposite of that for photosynthesis. Another type of food chain in the ocean does not depend on sunlight,however. This food chain depends on bacteria performining a process called Chemosynthesis. This process takes places in the rift zones where hot lava oozes from the crust. In this areas, bacteria produce food and oxygen by using dissolved sulphur compounds that escape from the lava. Organism then feed on the bacteria.( Ralph et al, 1993).The survival of any individual organism depends on the flow of matter and energy through its body. However, an ecosystem as a whole survives primarily through a combination of matter recycling (rather than one-way flow) and one-way energy flow ( Miller,2001; Ralp et al,1993). 1.20 ATMOSPHERE: pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! 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2nd International Conference On Engineering Research & Development: 1329 Innovations (15th – 17th April 2008), Benin City, Nigeria In comparison with the size of the Earth the atmosphere is the thin gaseous envelope which, at its upper, not exactly defied boundary in an altitude of about 1000Km, becomes space. Resulting from the much vertical ones horizontal movements are dominating in the entire atmosphere (Warharft,1997; Lozan et al,2001;Miller,2001). Composition of clean dry air in the atmosphere up to 80- 100km height. Main gases: Nitrogen N2 Oxygen O2 Argon Ar

Vol. % 78.09 20.95 0.93

Trace gases (selected): ppm Carbon dioxide* CO2 367 Neon Ne 18 Helium He 5 Methane* CH4 1.80 Krypton Kr 1 Hydrogen H2 0.5 Xenon Xe 0.08 Ozone* (troposphere) O3 0.03

* variable constituents (1999)

The atmosphere presents a well pronounced layered structure (see figure 1.1-4 ) for the subsystem atmosphere within the climate system the troposphere and the stratosphere are especially important. In the layer up to the upper boundary of the stratosphere in the region approximately 50Km altitude already 99% of the air mass is contained. In the troposphere, which is characteristic by a decrease of air temperature by 0.650C per 100m on average, weather phenomenon often accompanied by impressive phase transition of water? (P:19) the lowest kilometer of the troposphere where the atmosphere interact with the surface and also the anthropogenic influence on the atmosphere dominates. The average temperature distribution in the stratosphere is characterized in the lower part by small vertical gradients above, lower by an increase. The lather is caused by the ozone layer (maximum in about 25Km height) where highest maxing ration of ozone are observed. In this ozone layer solar radiation is observed and thus air is heated. The general composition of the atmosphere is constant up to 80-100Km altitude with the exception of some trace gases (hormosphere) as shoes in table 1.1-1 there is a large number (> 80) of trace gases in the lower atmosphere (most of them at very low concentration), which are absorbing and emitting in the thermal radiation region. The greenhouse gases are:Water vapour (H2O), CO2 , CH4, NO and tropospheric ozone (O3) causes 98% of the natural green house effect. Depending on molecular structure these gases contribute differently to the green house effect.Each of them has its own different green house potential which called global warming. The majority of natural trace gases are part of the global biogeochemical cycles. These cycles now also show deviation and modifications due to anthropogenic emissions that causes climate change (Hupfer, 2001). The clouds that formed predominantly in the troposphere are related to fundamental climate generating processes. According to their altitude, shape and vertical dimensions different types of clouds are a visible expression for the dynamic, thermodynamic and radiative processes in the atmosphere and the water cycle. Clouds are altering significantly the greenhouse effect( Lozan et al, 2001) At the same time the chemical composition of the troposphere has been considerably charge due to human action; mainly via burning of fossil fuels, but also the mixing ratios of green house gases: Example CO2, pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1330 Innovations (15th – 17th April 2008), Benin City, Nigeria CH4, NO2 O3 and CFCs increased dramatically in the troposphere. Whether the simultaneous climate change is due to the increase of green house gas mixing ratios (anthropogenic green house effect) or just a can not be said with certainly an increasing to the anthropogenic green house effect. Today climate is determined, to a large extent by the natural green house effect. For instance, the presence and radiative activity of these trace gases: water vapour (H2O), carbon dioxide (CO2), ozone (O3), nitrous oxide (NO2), methane (CH4), chlorofluoro carbons (CFCs) as well as parthy halogenated chlorofluoro carbons (HCFCs) are releaser into the atmospheric as a result of oil gases, the mean surface temperature of the Earth would be about -180C example about 33 degrees lower as compared to the present climate value of about 150C (Enquete commission 1991). The large temperature difference indicate the important climate influence of the green house gases whose mixing ratios are definitely have increased exponential during the last 130 years and will further increase in the near future this rise (in global warning) has caused an additional green house effect and will consequently result in a significant climate change which can be kept within tolerable limits if the global anthropogenic emissions of green house gases will be considerably reduced until 2050. Since the increase in tropospheric CH4 and NO2 mixing ratios is strongly to such activities as: agricultural industrial operational which needs to be intensified to provide food for the growing world population, mitigation strategies for reducing the anthropogenic green house effect have hither to been focused more on carbon dioxide (CO2) concentration in the environment. Although,the climate of the Earth is determined both by the incoming solar radiative and the heat radiation to space. On average an equilibrium as established between incoming solar radiation and outgoing heat radiation that determines the mean temperature distribution on Earth (Seiler and Hahn, 2001). The intensity of solar radiation reaching the earth is largely determined by the solar constant in which slight changes depending on solar activity exist and may by the changing distance to the sun. Part of the solar radiation concentrated in the visible part of the electromagnetic spectrum is backscattered by clouds, aerosol, or air molecules (Seiler and Hahn, 2001). Air also, gaseous emission are reflected at the surface/ point source of hydrocarbon pollution in the oil and gas Producing Communities in Niger Delta ecological zone of Nigeria. Generally, about half of the input of green house gases at the top of the atmosphere is warm up depending on the concentration of green house gases until heat radiation to space equals the net solar irradiance at the top of the atmosphere/ (Seiler and Hahn, 2001). Green house gases have the following important physical characteristic: they allow solar radiation to reach the surface nearly unhindered but significantly absorb heat radiation emitted from surface, causing a warming of surface and lower atmosphere. Analogy to the impact of glass (house) covering a green house this warming effect Seiler and Hahn, 2001).

1.21 THE ROLE OF LAND USE FOR CLIMATE CHANGE Land use changes as caused by human activities affect both vegetation structure and the water balances of terrestrial ecosystem. As main factors highly contributing to land use changes the following have to be considered: clear- cutting of forest. Conversion of forests into arable land and pasture, irrigation and drainage measures, soil tillage and Nitrogen fertilization liming, intensive cattle breading and inadequate land use technology. In general changes in land use pattern evolve from economic interests such as food supply and income (Hutfl,et al; 2001). It is well know that land use change attributed to a loss of plant phytomass , a change of mass budgets, losses of organic matter and thus, an over all alteration energy budget on related site especially in the oil producing Communities in the Niger Delta changes of energy budget are not restricted to the local scale but also global scale. In return, this affects the sink and source functions for green house gases and aerosols at the site level. Hence depending on their dimension land use changes may influence the global climate change (Huttl et al; 2001) use patterns, communal planning and ecodevelopments in the Niger Delta petroleum resources rich Communities 1.22 THE ROLE OF NATURAL AND ANTHROPOGENIC TROPOSPHERIC AEROSOLS IN CLIMATE EVOLUTION The term aerosol refers to a suspension consisting of atmospheric air in which immersed solid or liquid particles are floating. Aerosol are often meant to be dust particle which are dispersed widely and reach the upper troposphere and stratosphere thus playing and important role in transboundary effect of primary gaseous emission and global / regional climate change and variabilities .The presence of these aerosol has pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1331 Innovations (15th – 17th April 2008), Benin City, Nigeria been suggested to be a major reason explaining why the earth surface temperature increased moderately despite large green house concentration in the atmosphere. Although it is well known that particles effectively scattered light may absorb heat radiation. Aerosol particles are also indispensable cloud condensation nuculei. A large number of small aerosol result in cloud formation The sign of overall radiative effect on the earth atmosphere is the sum of all component of global aerosol is rather uncertain. And overall cooking effect can be assumed, considering that small and long lived aerosol particles are the most effective scatter and could return solar radiative into space before being absorbed. 1.23 SOURCES OF AEROSOLS Five major aerosol components in the troposphere are distinguished as follows: (i)Mineral dust, (ii) Sea salt, (iii) Sulphate, (iv) Carbonaceous matter and (v) Black carbon respectively. In addition aerosol can be composed of regionally from volcanic ash, biological debris , nitrate and industrial dust (in table 2.4.1) See table 2.4.1 > < (Overview of Natural Anthropogenic aerosols in the troposphere ( Andreae, 1995; Cooke and Wilson 1996). the aerosol is split according to major sources, reporting source strength, life time and the resulting column load (Andreae, 1995).The table also contains a rough assessment of each ones importance for the radiative effect. When combining the specific extinction coefficient of each component with its average column mass the result obtain is the optical thickness. Hence optical thickness is good measure for the potential of the respective aerosol component and anthrogenic sources reveals that especially for radiative impact the anthropogenic contribution is probably larger by or less than > 50% (Schulz, 2001). Studying the climate impact of the aerosol and gaseous emission requires henceforth to consider both the natural and the anthropogenic components. Cloud liquid water distributed on more and smaller cloud droplets, smaller droplets do scatter more incoming light and the aerosol indirectly would contribute to a cooking of the atmosphere. This is where the development of hydrogen fuel cell technology as an alternative source of energy can sustainable enhance environmentally friendly biogeoecnosis habitats. However, soot and the larger amount of mineral dust may absorb radiation and heat, and have the potential to retain energy in the lower atmosphere; where a high albedo associated to a bright surface such as: Desert, and Snow or low clouds would otherwise return radiation to space (Schuitz, 2001)

1.24 THE CLIMATE IMPACT OF GREEN HOUSE GASES (GHG) The gases: water vapour (H2O), CO2 O3 NO2, CH4 and the partially or fully halogenated hydrocarbons are radiatively active gasser. They all absorb terrestrial (heat) radiation and thus influence the transmission of the atmosphere in this domain increasing mixing rations of these green house gases lead to increased temperature at the surface and in lower atmosphere but it also to lower temperature in upper part of the atmosphere. The most important green house gas is water vapour (H20), which strongly absorbs in a very broad range of terrestrial radiation and thus contribute above two – thirds (2/3) to the green house effect of the atmosphere. However, from 8 to 15um ware length, where emission from the surface reaches a maximum at terrestrial temperatures, water vapour is comparably weak absorber. Therefore this spectral range is often called the water vapour window. Accordingly, all those gases are especially climatically relevant that absorb in this window. Like CO2, O3, N2O and CH4 as well as the partially and fully halogenated hydrocarbons. These substances can contribute substantially to the green house effect even at low mixing rations CH4 is a special case in this context. Since it does not only influence the radiative transfer in the atmosphere but, also important for hydroxyl (OH) radical concentration that modifies mixing rations of climatically relevant gases. Thus CH4 is causing an indirect green hous effect too (Seiler and Hahn, 2001) A measure for the climate impact of a green house gas is the specific green house potential or Global warming potential (GWP). GWP is defined as the radiative forcing caused by a mass unit (1Kg) relative to the same amount of CO2. Since the atmospheric residence times of certain greenhouse gases drifter strongly the GWP strongly depends on the time horizon for which the impact is integrated, therefore, GWP is reduced with reduced with growing time horizon for gases with residence time less than for CO2 as an example is the hydrocarbon methane (CH4). Because of the residence time influence is to needed for derivation of GWP of a certian gas detenled knowledge about it global cycle (about the distribution of pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1332 Innovations (15th – 17th April 2008), Benin City, Nigeria sources and sink) that is often still not available accurately enough. Thus the GWP values in table 2.2-1 have an in certainly range of at least ± 35%. For short lived trace gas like ozone or aerosols that are not given or of so less certain for a time horizon of 100 years GWP values vary between 21 for CH4 and 11700 years for CFC13. The GWP value for the most abundant CFC, namely F12 is 8500 years. A mass unit (1Kg) of F12 is as important as 8.5 tones of CO2 The estimation of the green house effect addition caused by a certain gas is via the so called radiative forcing (RF) defined as the change of net radiation flux density (energy per time and are unit) given in watts per square meter (watt / m2) at the tropopause cause by that gas at otherwise unchaged climate through the adjustment process to reach global radiation balance again. Radiative forcing is positive of the change leads to a warming of the lower atmosphere. The accumulated radiative forcing for the long lived green house gases like CO2 CH4 N2O, and CFCS, if counted since the start of industrialization, has reached about 2.5 Watt/ m2 above 1% in comparison to the set solar radiation flux density of 237 watt /m2 . the CO2 share reaches about N2O about 0.15 watt/ m2, Halogenated hydrocarbons contribute a bit less than O.3 watt/m2, in addition, the tropospheric ozone also has reached a contribution similar to accumulated CH4, however, as the uncertainly range from 0.2 to 0.6 watt / m2 indictes, the assessment is a difficult . the reason being that stratospheric ozone layer and been depleted since 1970s indicating a small negative radiative forcing of about – 0.1 watt /m2 resulting radiative forcing of about -0.1 watt /m2 results (IPCC: 1996 b, 2007). A negative radiative forcing also results for anthropogenic aerosol particles reacting days to weeks in the troposphere. Higher concentrations are therefore often restricted to area close to source of gaseous emission attributed pollution especially, in an independent postgraduate research thesis titled: Hydrocarbon pollution of soils in Iko Community, Akwa Ibom State (Gabriel, 2004 and 2007). See the tables; polluted and unpolluted soil parameters 4.1 and 4.2) respectively. The present observation do not allow a slid description of the troposphere aerosol mass budget, especially for the probably negative radiative forcing care values vary from 0.25 to 1.0 watt/ m2. Another important addition, in this context, is the indirect radiative forcing by aerosols as they modify a loud optical properties this indirect aerosol effect is estimated to be of similar magnitude as the direct IPCC 1996b, Honghton et al. 1996). Because of the large uncertainly of radiative forcing by aerosols, not less than the least caused by strong spatial and temporal variations the full aerosols effect as still so problematic that it will not be described here in more detail. However, since the water vapour amount in the troposphere is not influenced considerably by human activities, no radiative forcing is given here, despite the lack of a strong direct influence water vapour behaviour will dominate future climate as the warming caused by additional green housse gases will increase water vapour concentration in the lower atmosphere. And if other feed backs in the water cycle are added, the amplification factor by the water cycle is presently given at 2.5 (IPCC, 1996). 1.25 REASONS FOR THE GLOBAL ENVIRONMENTAL CHANGE IN THE GREEN HOUSE GASEOUS MIXING RATIOS. Green house gases in the atmosphere are part of biogeochemical cycles. They are formed by many processes and them emitted into the atmosphere where they undergo chemical and / or physical transformation. Finally they reach the surface again by dry and wet deposition. Example either by atmospheric turbulence or in precipitation. A dynamic equilibrium exist between the strength of sources andsin that determines mixing rations and residence time in the atmosphere the residence time are rather different varying from 12years for CH 4, and 120 years for N2O to several thousand years for some new man made green house gas. Mankind interferences with these biogeo chemical cycles vic on an fold activities, thereby manipulating the strength of source and sink and this tropospheric mixing ratios of the gases. Theemost important activity is this context – the burning of fossil fuds such as: Oil, coal, and natural gas flaring that leads to the emission of about 6 Giga- tournes of carbon (Gt of C) or 2 Gtga of carbon dioide (Gt of CO2) into the atmospherer and besides many other pollutants (Lassey,et al) is emitted in industrialized countries that constitute only 25 percent of the world population. In addition about 1.5Gt of C2 or 5.5 Gt of CO2 per year item from slash and burn practice in tropical rain forests when there are converted. Into agricultural land. This anthropogenic emissions have hereby reached the enormous amount of 30 at of CO2 per year. (IPCC 1996a) whilst the CO2 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1333 Innovations (15th – 17th April 2008), Benin City, Nigeria emission the last 30-40 years emissions from fossil fuel burning have still increased on average by about 1 to 2 percent per year even after the first Oil prize crisis in 1973. in its Energy out work 1997 the international Energy Agency (IEA) projected a yearly global CO2 emission of 9.7 Giga- tounes of carbon (Gt of C) in 2015, equivalent to a 50 percent increase in the next to decades and this to a futher increase of CO2 mixing ratios in the atmosphere. About half of the anthropogenic CO2 remains in the atmosphere leading to the observed increase of average CO2 mixing ration. The other half is entering the ocean or is sequestered by the terrestrial biosphere. The ocean sink is stimulated to reach about 2 Gtg tonues of carbon (2 Gt of C) or 7.3 Gt of CO2 per year. It is not excluded that the sequestering by ocean and terrestrial biosphere will shink leading to an accelerated rise of CO2 level in the atmosphere. In addition, the tropospheric CO2 content increase would even continues after stabilization of emission rates since the long life time of anthropogenic CO2 of about 100 to 200 years does not allow rapid equilibrium between emission rates and sequestering rate; but rather leads to a delay of decades of centuries. At stable global 1 CO2 emission rates the tropospheric CO2 mixing ration would reach about 500 ppmv in 2100 and finally become stable at 750ppmv after centuries can only be achieved by rather immediate and strong gaseous emission reductions scheme (CRS). In contrast to CO2 the increased tropospheric mixing ratios of CH 4 and NO 2 are largely due to agricultural activities needed to feed the growing world population. At present 60 to 80% of global CH 4 emission reaching about 600 million tounes per year is due to anthropogenic action, especially from rice cultivation and animal husbandry (IPCC 1996 b). also production and distribution of natural gas coal mining and anaerobic decomposition in land fills are strong CH 4 sources (Seiler and Hahn 2001), while large emissions from fossil fuel use can be reported, there is exist at present no major possibility to sustably reduce CH 4 emissions from agriculture and natural nitrogen fertilization via denitrification or nitrification by microbes in soils. Thus; further NO2 emission increase this can not be avoided. In the 21st century feed backs between climate charge and the natural global carbon cycle will become visible in CO2 and CH4 emission . at present the net effect of positive and negative feed back can not be assessed and this also not the effect for the mixing ratios of the growth of tropospheric ozone mixing rations is due to increased emissions of nitrogen oxides (NOx), volatile organic compounds (VOC), carbon monoxide (CO) and methane (CH4) the lather three gaseous pollutants are oxidized in the atmosphere via catalytic reactions involving NOx whereby also ozone (O) is formed, O3 mixing ratio can value during regional photosmog episodes which are above allowed thresholds and this lead to considerably damage on human health effects and living (bio) plants and animal gaseous emission of pollutants, at present large efforts are under way to strongly reduce NOx and VOC emissions from road traffics example by using catalytic converters. Therefore a further increase of tropospheric O3 mixing ratios in large regions of the northern hermisphere seems rather certain taken together, the growth of gren house gas mixing ratio in the 1980s was due to about 50% to combustion of fossil fuels, about 30% originated from agricultural activities and about 20% from industry (the lather mainly caused by the production of halogenated compounds – example CFCS) (ENQUETE COMMISSION, 1991), 1.30

CLIMATE CHANGE AND SUSTANBLE DEVELOPMENT

Climate is identical to the average meteorological parameters or climate elements. Rather, the climate has to be defined as a generalization of the strongly varying weather. Therefore, the best known correct definition of climate elements are the air temperature near the surface (2m altitude above ground) and precipitation amount as well as parameters derived from them. Additional climate elements include; air, pressure, wind velocity and direction, humidity short wave and long wave radiation, the heat balance the different trace constituents in the atmosphere; but also cloudiness, cloud types, sunshine duration, reflectivity of the surface and neurons others also combined parameters (Hantell, 1986). In climatology, according to the international agreement thirty (30) years period of observation is called a reference synthesis of the weather over a period which is long enough to be able to determine its statistical characteristics. During the 20th century land use changes caused by an increasing demand for food, wood, economic purpose and energy have dramatically accelerated. Recently the dimension of this process with regard to global climate change both on the regional and global scale has bewared oblivious. It is assumed that deforestation in the tropics (Huttl, cited in Lozan et at; 2001) exploitation of natural crude oil and gaseous flaring had increased the emission of green house gases into the atmosphere with subsequent changes of pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1334 Innovations (15th – 17th April 2008), Benin City, Nigeria global warming (heat) and water budget. Land use changes account for about 2% of the carbon dioxide, 60% of methane and 23% of the nitrous oxide emission world wide. Hence,it has become evident that strategies for ecological sound land use and practice alternative energy source are needed to counteract the climate change on the global scale on land use changes as caused by human activities affect both the vegetative structure and the water balances of terrestrial ecosystem (Huttl, Cited in Lozan et al; 2001). Presently gaseous land use emissions make up over one third ( 1/3 ) of the total anthropogenic emission of green house gases and about ¾ of the total anthropogenic emission of methane (CH4) the impact of land change on the release of methane is under anoxide conditions and produced through decomposition of organic substances due to fermentative processes of microbial organism (Stevens and Laugh, 2001 cited in Lozan et al 2001; Seiler et al, 2001). Climate change has become a source of concern in recent times especially depletion (NIER,2004); and sustainable development on climate change (IPCC,2007) indicated that the last decade has been the warmest in hundred of years and many part of the world including the coastal and mangrove region of the Niger Delta ecosystem in Nigeria (Akpan, 2007); have suffered major heat waves, floods, drought and extreme weather events in Nigeria’s climate is getting increasing warmer and uncomfortable in recent times and should not be over look as the gaseous emission of petroleum effluent and industrial pollutions (Gabriel,2004 and 2007). Currently, there is a net global emission of about 7 billion tons annually into the atmosphere. Statistics from other sources indicate that between 1850 and 1995, a total of 365 billion ton of carbon was emitted through anthropogenic sources. The oceans vegetation and soil absorb about 208 billion tons leaving extra 160 billion tons in the atmosphere the implication of this figures project is that the emission of the GHG is more than the carbon sink can absorb. This invariably meaning that the earth biosphere can no longer heal itself (carbon finance, 2007, financial standard,2007 and 2008,Akpan, 2007), IPCC, 2007).

1.31

SUSTIANABLE DEVELOPMENT:

Sustainable Development (SD) to World Commission on Environment and Development (WCED,1987; Brundtland Report, 1987) states that, “SD is a development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. The guiding rules are that people must share with each other and care for the Earth. Humanity must take no more from nature than nature can replenish. This in turn means adopting lifestyles and development developments that respect and work within nature’s limits.This can be done without rejecting the many benefits that modern technology has brought, provided that technology also works within those limits (IUCN, 1987).It is the believe of some people that the concept of sustainable developments should include preserving the environment for orther species as well as for humanity. The term SD refers to achieving economic and social development in ways that do not exhaust a country’s natural resources (Ashford,1995). In the WCED words the sustainable development is a process of change in which the exploitation of resources, the direction of investments, the orientation of technological development, and institutional change are made with the future as well as present needs (WCED,1987,IUCN,1987, Uwem, 2005; UN / MDGs 2005-2015;AK-SEED,2004).This concept is being endorsed by many governmental and non-governmental organizations (like NGOs ) around the world as a framework for promoting economic development that is environmentally sustainable and socially equitable.National governments are developing policies and implementing regulations consistent with this concept of Sustainability and Developments (AKSG, 1990-2004; AKSG / UNDP,2005 and 2007).It is also being incorporated into policies and programmes of major development aid organizations, such as the World Bank, which now requires compliance with specified environmental standards and guidelines as a condition of its projects loans and grants for development projects ( World Bank, 1994;Anderson, et al;1996).Although, the Brundtland report provided a solid foundation for sustainable development in 1987, but it failed to explain how to implement it . Indeed, the emphasizes that the ways in which countries achieve sustainable development will vary among the different economic and political systems around the world (Hilson,2001;Environmental Matters,2005 and 2006; IIED,2007; CEC,2007). Sustainability as a concept is a long term and, development as gradual process of change; which shall be realistic to bring about positive and long lasting impact on the populate as for which it is intended. The fundamental effect of global warming on coastal region of Nigeria is as the result of gaseous emission pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1335 Innovations (15th – 17th April 2008), Benin City, Nigeria attributed pollution in oil producing communities in Nigeria. Hence ,public awareness campaign and communal integration of environmental concerns into the policy objectives, projects execution and programme of governance at the grass-root (Ward) levels.This can be achieve through social re-engineering incollaboration with a balanced ecological technology while upholding community base adaptation (CBA) exchange to attain sustainable development using Global Environmental Facility (GEF) from World Banlk multilateral investment coorporation incollaboration with global environmental organization (GEO) as Centre for Environmental Justice and Ecological Developmet (CEJED_NGO’s) dynamics in the abatement of gaseous emission attributed pollution in Iko Community (Gabriel,2004 and 2007; DFID / CEJED, 2007; UNESCO,2007). 1.32

DEVELOPMENT:

Development according to Dudley Seers (1969) in a presidential address presented during the 11th session of international Development SID World Conference observed that a country’s level of development can be observed by the degree to which poverty, unemployment and inequality exist. As these banes of developments that need urgent attention.(IDR,1977; Dudley, 1969; Gabriel, 1998.). Recently, developments reports: (DFID : 2006, 2007 and 2008; G8 Summit,2005; Developments, 2006) calls on the United Kingdom (Her Majesty Government) to lead rich countries in taking action to curb poverty, environmental pollution and global warming which are double burden truism that, human induced climate change will be having adverse effect on many of the world’s poorest people (HM Government 2006,2008; IPCC,2007 and VATICAN NEWS,2008,).Both the Human development Report !996 and the World Development Report 1997 follow in a long tradition by listing policies and action to make the world a better place for the poor. The worst polluter on the environment is poverty according to Ghandi (Stockholm Summit, 1972; W E F, 2007; U N C E D, 1992 Developments,2002).The objective of development is well being for all (Clark,2006; EEL / EEA and CEJED,2007 and 2008; G8 Summit,2005; Developments,2006 and 2007). It also proposes a resolution in development thinking that would see poor countries/regions using renewable energy to power a new and clean era of prosperity ((Developments,2006, W B I ,2007; W E F, 2007).This report according to Sir John Houghton, former Co-Chair of the Scientific Assessment Working Group of Intergovernmental Panel on Climate Change (IPCC,2007) further exposes clearly and starkly the devastating impact that human induced climate change will have on many of the world’s poorest people ( IPCC, 2007;Iniodu,2005; Elisabert,2006 and 2007). Globally, for over the past 200 years, burning fossil fuels such as coal and gas has increased green house gases in the earth’s atmosphere causing temperature rise, global warming and climate change (IPCC,2007;IIED,2006,UNFCCC,2006,UNITAR,2006;Carbon Fianace,2007; Environmental Finanace,2007 and 2008.A palaeoclimatic studies use change in climatically sensitive indicators to infer changes in global climate on time scales ranging from decades to millions of years. Such proxy data may be influenced by both local temperature and other factors such as precipitation and are often representative of particular seasons rather than full years (Dutton,2001, Gile, 1976; Warharft,1997, NIER,2004). Other environmental effects on the ecological degradation in the ecosystem are fatal causes of climate change and global warming (Edward Elgar,2003 and 2007, IPCC,2007). The climate change increases the intensity of natural disasters, rising sea levels which may cause large numbers of refugees, higher temperature, spread of diseases, and short rainy seasons in some place can cause crop failure (Odjugo,2000, DFID,2006). A number of landmarks enumerated above have of course developed into a specified field of study namely, dynamic or process geomorphology; which is concerned with the study of processes such as weathering, pedogenesis, denudation and deposition; structural geomorphology, with emphasis on geological attributes such as endogenic dynamic process and the effect of rocks and structure, and climate, including climatogenetic, geomorphology to name only a few (Faniran and Jeje, 1983). The present tropical humid geomorphology is based on principle and assumption of climatic (climato- genetic) geomorphology.The climatic geomorlogy postulates that , different climates, by affecting processes develop unique assemblage of landforms. These processes and teir relationship with climate have been systematically analysed with the view to defining morphogenetic regions of the world wide basis (Budel,1948 and 1963).According to Faniran and Jeje (1983), the protagonists of the concept of climatic geomorphology, variations in climatic elements exert a controlling influence on all other components , including structural components, consequently every climatic zone has its own specific complex of dynamic processes which creates pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1336 Innovations (15th – 17th April 2008), Benin City, Nigeria distinguishable landforms assemblage. The most important of this concept of climatic geomorphology are thus: i) Landforms and landform processes differ significantly between different climatic areas. ii) These differences are the result of area variations in climatic elements or parameters. iii) Climatic changes, including times, have not masked the evidence of climate landforms relationships where they exist. A palaeoclimatic studies use change in climatically sensitive indicators to infer changes in global climate on times scales ranging from decades to millions of years. Such proxy data may be influenced by both local temperature and other factors such as precipitation, and are often representative of particular seasons rather than full years (IPCC,2007). In 1st August,2003, during an international conference on Earth’s Observation’s Summit (2003), the president of United States of America announced plan to speed research in climate change, measure climate effects from burning fossil fuel and industrial production of warming gases (http://www.cnn.com/earth summit.2003). Awareness concerns of the environmental effect of global warming on coastal regions (Akpan,2007 and 2007a) and; gaseous emission attributed pollution in oil producing Communities in the Niger Delta ecological zone of Nigeria, requires alternative sources of energy, and especially; in the mode of operation /exploration / production in oil and gas technology ( such as the Hydrogen Fuel Cell), this alternative source of energy and mode of resource utilization is environmentally friendly with zero carbon emission in the form of water vapour. Sir William Grove invention the first fuel cell in 1839. . Grove knew that water could be split into hydrogen and oxygen by sending an electric current through it (a process called electrolysis). He hypothesized that by reversing the procedure you could produce electricity and water. He created a primitive fuel cell and called it a gas voltaic battery. After experimenting with his new invention, Grove proved his hypothesis. Fifty year later, scientist Ludwig attempting to build a practical model to produce elec tricity.

INVENTION OF THE FUEL CELL 1.40 THE INVENTION FUEL CELL Sir William grove invented the first cell in 1839. Grove knew that water could be split into hydrogen and oxygen by sending an electric current through it (a process called electrolysis) He hypothesized that by reversing the procedure you could produce electricity and water – Grove created a primitive fuel cell and called it a gas voltaic battery (GVB) After experimenting with his new invention Grove proved his hypothesis. Fifty years later, scientists Ludwig mond and Charles langer coined the term “Fuel Cell” while attempting to build a practical model to produce electricity. You have probably heard about fuel cells. In 2003, President Bush announced a program called the Hydrogen Fuel Initiative (HFI) during his state of the Union Address. This initiative, supported by legislation in the Energy Policy Act of 2005 (EPACT 2005) and the Advanced Energy initiative of 2006, aims to develop hydrogen, fuel cell and infrastructure technologies to make fuel-cell vehicles practical and cost-effective by 2020. The United States has dedicated more than one billion dollars to fuel cell research and development so far. So what exactly is a fuel cell, anyway? Why are governments, private businesses and academic institutions collaborating to develop and produce them? Fuel cells generate electrical power quietly and efficiently, without pollution. Unlike power sources that use fossil fuels, the by products from an operating fuel cell are heat and water. But how does it do this? In this article, we’ll take a quick look at each pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1337 Innovations (15th – 17th April 2008), Benin City, Nigeria existing or emerging fuel cell technologies. We’ll detail how polymer electrolyte membrane fuel cells (PEMFC) work and examine how fuel cells compare against other forms of power generation. We’ll discuss the potential applications of fuel cells. If you want to be technical about it, a fuel cell is an electrochemical energy conversion device. A fuel cell converts the chemicals hydrogen and oxygen into water, and in the process it produces electricity. The other electrochemical device that we are all familiar with is the battery. A battery has all of its chemicals stored inside, and it converts those chemical into electricity too. This means that a battery eventually “ goes dead” and you either throw it away or recharge it. With a fuel cell, chemicals constantly flow into the cell so it never goes dead- as long as there is a flow of chemicals into the cell, the electricity flows out of the cell. Most fuel cells in use today use hydrogen and oxygen as the chemicals. In the next section, we will look at the different types of fuel cells. 1.41 HOW FUEL CELLS WORK 1.42 FUEL CELL TECHNOLOGY Technically, a fuel cell is an electrochemical energy conversion device. A fuel cell device converts the chemicals hydrogen and oxygen into water and in the process produces electricity. With a fuel cell, chemicals constantly flow into the cell soit never goes dead. As long as there is a flow of chemicals into the cell, the electricity flows out of the cell. Most fuel cells in use today use hydrogen (H) and oxygen (O) as the chemical. Polymer Exchange Membrane Fuel Cells The polymer exchange membrane fuel cell (PEMFC) is one of the most promising fuel cell technologies. This type of fuel cell will probably end up powering cars, buses and may be even your house. The PEMFC uses one of the simplest reactions of any cell. First, let’s take a look at what’s in a PEM fuel cell: Figure 1. The parts of a PEM Fuel Cell As shown in figure1 there are four basic elements of a PEMFC: i The anode, the negative post of the fuel cell, has several jobs. It conducts the electrons that are freed from the hydrogen molecules so that they can be used in an external circuit. It has channels etched into it that disperse the hydrogen gas equally over the surface of the catalyst. ii The cathode, the positive post of the cell, has channels etched into it that distribute the oxygen to the surface of the catalyst. It also conducts the electrons back from the eternal circuit to the catalyst, where they can recombine with the hydrogen ions and oxygen to form water. iii The electrolyte is the proton exchange membrane. This specially treated material, which looks something like ordinary kitchen plastic wrap, only conducts positively charged ions. The membrane blocks electrons. For a PEMFC, the membrane must be hydrated in order to function and remain stable. iv The catalyst is a special material that facilitates the reaction of oxygen and hydrogen. It is usually made of platinum nanoparticles very thinly coated onto carbon paper or cloth. The catalyst is rough and porous so that the maximum surface area of the platinum can be exposed to the hydrogen or oxygen. The platinum-coated side of the catalyst faces the PEM. Figure 2 Shows the pressurized hydrogen gas (H2) entering the fuel cell on the anode side. This gas is forced through the catalyst by the pressure . when an H2 molecule comes in contact with the platinum on the catalyst, it splits into two H+ ions and two electron (e). The electrons are conducted through the anode, where they make their way through the external circuit (doing useful work such as turning a motor) and return to the cathode side of the fuel cell. Meanwhile, on the cathode side of the fuel cell is oxygen atoms. Each of these atoms has a strong negative charge. This negative charge attracts the two H+ ions through the membrane, where they combine with an oxygen atom and two of the electrons from external circuit to form a water molecule (H2O).

Chemistry of a Fuel Cell

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Cathode side: +

2nd International Conference On Engineering Research & Development: 1338 Innovations (15th – 17th April 2008), Benin City, Nigeria

This reaction in a single fuel cell produces only about 0.7 volts. To get this voltage up a reasonable level, many separate fuel cell must be combined to form a fuel-cell stack. Bipolar plates are used to connect one fuel cell to another and are subjected to both oxidizing and reducing conditions and potentials. A big issue with bipolar plates is stability. Methallic bipolar plates can corrode, and the byproducts of corrosion (iron and chromium ions) can decrease the effectiveness of fuel cell membranes and electrodes and low-temperature fuel cells use lightweight metals, graphite and carbon/ thermoset composites (thermoset is a kind of plastic that remains rigid even when subjected to high temperatures) as bipolar plates material. 1.43 TYPES OF FUEL CELLS The fuel cell will complete with many other energy conversion devices including the gas furbine ( in power matt) the gasoline in car engine and, the battery (in lap top). Combustion engines like the turbine and gasoline burn fuels and use the pressure created by the expansion of the gases to do mechanical work. Batteries convert needed fuel cells should do both mechanical work and conversion of chemical (into electricity. A fuel cell provides a DC (direct current) voltage that can be used to power motors, lights or any other electrical appliances there are several different types of fuel cells, each using a different chemistry. Fuel cells are usually classified by their operating temperature and three type of electrolyte they use. Some types of fuel cells work well for use in stationary power generation plants. Others may be useful for small portable applications or for power cars. The main types of fuel cell includes the following: i Polymer Exchange membrane cell (PEMFC) ii Solid oxide fuel (SOFC) iii Alkaline carbonate fuel cell (AFC) iv Molten carbonate fuel cell (MCFC) v Direct methanol fuel (DMFC) Polymer exchange membrane fuel cell (PEMFC) The department of Energy (DOE) is focusing on the PEMFC as the most likely candidate for transportation applications. The PEMFC has a high power density and a relatively low operating temperature (ranging from 60 to 80 degrees Celsius, or 140 to 176 degrees Fahrenheit). The low operating temperature means that it doesn’t take very long for the fuel cell to warm up and begin generating electricity. Direct-Methanols Fuel Cell (DMFC). Methanol fuel cell are comparable to a PEMFC in regards to operating temperature, but are not as efficient. Also the DMFC requires a relatively large amount to platinum to act as a catalyst, which makes these fuel cells expensive. In the following section, we will take a closer look at the kind of fuel cell the DOE plans to use and power future vehicles- the PEMFC. Solid oxide fuel cell (SOFC) These fuel cell are best suited for large-scale stationary power generators that could provide electricity for factories or towns. This type of fuel cell operates at very high temperatures ()between 700 and 1,000 degrees Celsius). This high temperature makes reliability a proble, because parts of the fuel cell can break down after cycling on and off repeatedly. However, solid oxide fuel cells are very stable when in continuous use. In fact, the SOFC has demonstrated the longest operating life of any fuel cell under pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1339 Innovations (15th – 17th April 2008), Benin City, Nigeria certain operating conditions. The high temperature also has an advantage; this process is called Cogeneration of heat and power (CHP) and it improves the overall efficiency of the system . Alkaline fuel cell (AFC) This is one of the oldest designs for fuel cell; the United State space program has used them since the 1960s. the AFC is very susceptible to contamination, so it requires pure hydrogen and oxygen. It is also very expensive, so this type od fuel cell is unlikely to be commercialized. Molten-carbonate fuel cell (MCFC) Like The SOFC, these fuel cells are also best suited for large stationary power generators. They operate at 600 degrees Celsius, so they can generate steam that can be used to generate more power. They have a lower operating temperature than solid oxide fuel cells, which means they don’t’ need such exotic materials. This makes the design a little less expensive. Phosphoric-acid fuel cell (PMFC) The phosphoric fuel cell has potential for use in small stationary generators. They operate at a higher temperature than polymer exchange membrane fuel cells, it has a longer warm up time. This makes it unsuitable for use in cars. 1.44 FUEL CELL EFFICIENCY Pollution reduction is one of the primary goals of the fuel cell technology. Example, by comparing a fuel-cell powered car to a gasoline-engine-powered car and a battery-powered car; you can see how fuel cells might improve the efficiency of cars today. Hydrogen Hydrogen is the most common element in the universe. However, hydrogen does not naturally exist on earth in its element form. Engineers and scientists must produce pure hydrogen from hydrogen compounds, including fossil fuel or water. In order to extract hydrogen from these compounds, you have to extent energy. The required energy may come in the form of heat, electricity or even light.

Since all three types of cars have many of the same components (tires, transmissions et cetera), it is important to compare efficiencies of cars up to point where mechanical power is generated If the fuel cell is powered with pure hydrogen, it has the potential to be up to 80-percent efficient. That is, it converts 80 percent of the energy content of the hydrogen into electrical energy. However, we still need to convert the electrical energy into mechanical work. This is accomplished by the electric motor and inverter. A reasonable number for the efficiency in generating electricity, and 80-percent efficiency converting it to mechanical power. That gives an overall efficiency of about 64%. Honda’s FCX concept vehicle reportedly has 60-percent energy efficiency. 1.50 CARBON SEQUESTRATION One effort being pursued to reduce the release of green house gases into the atmosphere is sequestration of CO2 from Integrated Gasification Combine Cycle (IGCC) and Oxy-fuel power plants. This approach pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1340 Innovations (15th – 17th April 2008), Benin City, Nigeria however, requires significant compression power to boost the pressure to typical pipe–line levels. Carbon Capture and Storage (CCS) is a technological approach to mitigate global warming by capturing carbon dioxide (CO2) from large point sources such as fossil fuel power plants and, storing it instead of releasing GHG into the atmosphere. The Technology for large scale capture of CO2 is already commercially available and fairly developed. Although CO2 has been injected into geological formation for various purposes, but the long term storage of CO2 is relatively untried concept and as yet no full CCS system (IPCC, 2007). CCS when applied to a modern conventional power plant could reduce CO2 emission to the atmosphere by approximately 80-90% compared to plant without CCS. Capturing and compressing CO 2 requires much energy and would increase the fuel need of plant with CCS by 11-40%. These and other system costs are estimated to increase the cost of energy from a new power plant with CCS by 21-91%. These estimates apply to purpose-built plant which may be near a storage location. By applying the technology to preexisting plants or plants far from a storage location it will be more expensive. Storage of the CO2 is envisaged either in deep geological formations, in deep oceans masses or in the form of minerals carbonates. In the case of deep ocean storage there is a risk of greatly increasing the problem of ocean acidification, a problem that also stems from the excess of CO2 which are already in both the atmosphere and oceans. Geological formations are currently considered the most promising in geo-sequestration sites and, these are estimated to have a storage capacity of at least 2000 Gt CO2. Currently, 30 Gt per year of CO2 is emitted due to human activities (IPCC: 2007, 2007a) SUMMARY Gaseous flaring by multi national oil companies in the oil and gas producing communities in the Niger Delta ecological zone of Nigeria should forth with abate global green house gases emissions in accordance with the current trends and in accordance with Intergovernmental Panel on Climate Change Fourth assessment report. “Climate Change 2007: Mitigation of Climate Change”. RECOMMENDATIONS My recommendation is for Environmentalist, Scientist, Technologist, Engineers and various stakeholders in Nigeria should evolve in the practical development of alternative energy source like fuel cell technology. Because the global trends. The integrated environmental management system is here by recommended so that local authorities can make adequate response to environmental pollution. This can be achieved through adequately financed, properly trained and well staffed environment departments in local government holistic community environment management. The establishment of pollution control boards (PCB) at the state level is recommended to monitors oil and gas communities and, the function of PCB shall include the following: To Advice, plan and, implement policies concerning matters prevention and control of environmental pollution in the Niger Delta communities. CONCLUSION In conclusion the federal government and local councils in Nigeria should developed the global environmental facility (GEF) policy as enshrined in the United Nation Environmental Programme (UNEP); and more carbon neutral investments from the World Bank Carbon Project. ACKNOWLEDGMENT My profound gratitude is unto Engr. (Associate Professor.) Anthony J.Akpan for his relative and astronomical concern about holistic human capital development. Others in the line-up are: Professor Imoh E. Ukpong, Professor Eno J. Udo, Professor Christian O.Enoh (Emiritus); Dr. Emmanuel M. Akpabio “Aristotle”,Dr. Emmanuel P. Udofia,Professor Etim I. Udoessien,Professor Philip A. Akpan, Professor Idorenyin B. Inyany, Engr. Anietie O. Umana and Honourable (Obong) Umana O. Umana; and Dr. (Barr.) Aquqowo Essien. Objectively, the joy of knowledge and the state of Mankind’s livelihood is bright and colourful to all pragmatic Environmentalist, Scientist, Engineers and future Technologist that shall continue this quantum global creativity for sustainable eco-development and strategic resources management in our pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1341 Innovations (15th – 17th April 2008), Benin City, Nigeria relative habitats. Above all especially, to the Unborn Millennium Children and best regards to the present nursery Pupils in all academies of learning through out the spatial Earth. I also wish to acknowledge the entire network team members in our global environmental organization (GEO) as in: CENTRE FOR ENVIRONMENTA JUSTICE AND ECOLOGICAL DEVELOPMENT. Via: The Co-ordinator CEJED_NGO (RC: 431521) # 53 Brooks Street( Daqsen Motel) ,P.O.Box 2471- Uyo Capital City , Akwa Ibom State- Nigeria. E-mail: [email protected] Or: The EPA/ PEM/ IED Consultant, Postgraduate School, Environmental and Resource Management c/o Geography and Regional Planning, University of Uyo, P.M.B. 1017-Uyo Capital City , Akwa Ibom State- Nigeria.E-mail: gafconsult [email protected]

(ICERD08001) RECYCLED TIRE MATERIALS AS COMPONENTS OF NOVEL STRUCTURES

Joshua L. Neal Henry Molded Products Inc. Lebanon, PA USA Madara M. Ogot University of Nairobi Enterprises and Services Ltd Nairobi, Kenya [email protected]

The aim of this study was to characterize the material properties of recycled tire materials and develop methods for their use in the construction of novel structures, and was directly influenced by the need for building for sustainability. The study looked at ways of improving the unconventional aesthetics of current building methods, while keeping the cost of materials and construction equal to or less than the cost traditional construction methods. We propose a construction method using layered tire-tread strips that would allow for the traditional flat-faces and straight lines of construction. It was found that layering tire-treads would require a pre-compression process prior to loading. This process fulfills two requirements: inhibiting further compression of the structure during loading, and creating a heterogeneous structure by adhering the tire-tread layers through frictional forces. In order to determine whether this process is feasible, analytical models were developed using experimental data to estimate material properties. Four different construction methods were investigated both analytically and experimentally, and observations presented.

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2nd International Conference On Engineering Research & Development: 1342 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD08277) Appropriate design of rural roads

O.I. Odumodu, Dept. of Civil Engineering, Federal Polytechnic, Oko, Anambra State, Nigeria

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2nd International Conference On Engineering Research & Development: 1343 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08280) IMPROVED SAWDUST BRIQUETTE: AN ALTERNATIVE SOURCE OF FUEL

J.O Osarenmwinda* and S Imoebe Department of Production Engineering, University of Benin, Benin City,Nigeria. *joosarenmwinda @yahoo.com

ABSTRACT The production of an improved sawdust briquette, an alternate source of fuel has been achieved. In addition to sawdust other constituents of the briquette were silica (sharp sand), starch and kerosene. The density, ash content, calorific values and moisture content of briquette were determined. The composition of starch and kerosene was constant throughout the experiment. It was observed that as silica percentage was increased, there was an increase in the briquette calorific value until maximum value of 20%. The sample which gave the best calorific value was with percentage compositions of 60% sawdust, 20% silica (sharp sand), 5% kerosene and 15% starch with a calorific value of 12.68mJ/kg .The produced briquette had a higher calorific value than wood and other agro waste it was compared with.

Keywords: briquette, sawdust, calorific value, ash content, silica, starch *Corresponding Author INTRODUCTION Despite the numerous sources of energy in Nigeria, we are still passing through an unprecedented energy crisis. The non-renewable energy sources such as gas and kerosene are progressively getting out of reach and electricity supply, another conventional energy source, is epileptic where available or non available at all in some part of the country. Wood fuel, though relatively cheap, its use is causing serious deforestation problems in the country. These developments call for the search for alternative source of fuel for domestic and industrial use. Sawdust (wood waste) in particular, is one of the other forms of biomass fuel that has attracted attention. Sawdust is presently regarded as waste byproducts of wood in sawmills, and are abundant in the southern region of Nigeria.[1] The conversion of sawdust and other agricultural waste to high-energy briquettes for cooking and drying have been investigated and found to be feasible. [2-4]. The compaction of these loosed combustible materials for fuel making purpose has been a long age practices, thus making it a commercial product. Sawdust can also be subject to various conversion techniques to help reduce its bulky forms, lower its moisture content, give it a uniform size, shape, material properties and improve its burning characteristics. One of the oldest techniques used is called briquetting, which have been practiced in Europe since 19th century. [5]. Briquette is considered as an attempt to link agric with fuel supply and its use. Thus, it is a biomass densification, the conversion to solid form of forest trees byproduct (sawdust) by means of mechanical pressure through reduction of its volume for easy handling, use and storage [6]. The most important advantages of briquette are its low sulphur,relative freedom from dust, ease of handling and most especially with a high calorific value compared to the calorific value of ordinary fire wood. One of the most important factor in determination of the value of fuel is its calorific value, that is the amount of energy per kg it gives off when burned. Although briquettes, as with most solid fuels, are priced by weight or volume, market force will eventually set the price of each fuel according to its energy content. However, the production cost of briquette is dependent on its calorific value as well as the transportation and handling cost. The calorific value can thus be use to calculate competitiveness of a pressed fuel in a given market situation [6-8]. There are other factors, which influence the price marketability such as ease of pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1344 Innovations (15th – 17th April 2008), Benin City, Nigeria handling, burning characteristic, heat intensity, but calorific value is the most demanding factor for marketability. This work therefore focused on producing an improved briquette from sawdust with the addition of silica (having good heat retaining capacity) and kerosene using starch as binder with the view of improving the briquette calorific value since calorific value can thus be used to determine the competitiveness of a pressed fuel in a given market situation.

METHODOLOGY MATERIALS In the production of the briquette, materials used are Sawdust, Silica (sharp sand), Kerosene and Starch EQUIPMENTS Equipments used during the production of the sawdust briquette are measuring cylinder, mixing plate, Wooden mould, hydraulic press, Muffles furnace, electric oven, Weighting machine, Silica dish, Desiccators, Thermometer, Water, Beaker and Stop watch BRIQUETTE PRODUCTION In the production of briquette, sample 1, 80%, 0%, 5% and15% by volume of sawdust, silica, kerosene and starch respectively was measured using the measuring cylinder and their corresponding mass determined using a weighting machine and was then poured into the mixing bowl. These constituents were thoroughly mixed to obtain a homogenous mixture. The mixed constituents were then poured into a prepared mould (153mm x 100mmx70mm). The loosed state of the mixture was then compacted using a hydraulic press with a force of 10KN. The produced briquette was carefully remove from the mould and allowed to dry in an oven for about 1hr at temperature of 105°Ñ. This was labeled sample 1. This same process was followed to obtain sample 2-6 using the percentage compositions as shown in table 1. In the briquette production, the percentage of starch and kerosene used throughout the experiments was 15% and 5% respectively.

DETERMINATION OF DENSITY The density of each the briquette was obtained by weighting the dried sample using the weighing machine. The volume of each briquette produced was then obtained, by measuring its length breath and height using a veinier caliper. These obtained values were substituted into equation (1) to obtain the density of the briquette. R=

md (kg/m3)v

--

--

(1)

Where R =density of briquette, md = mass of briquette = Volume of briquette. DETERMINATION OF MOISTURE CONTENT The moisture content of the briquette was determined by weighting the mass of the briquette, this value was recorded, and the briquette was placed in an oven at temperature of 105°Ñ for about 16 hours. The briquette was monitored every 2 hours to determine its change in mass, until there were no changes observed. The oven dried sample was weighed and its mass recorded. The moisture content was obtained using equation (2). % Moisture content =

A  B A

X 100% --------------(2) [9]

Where A = mass of briquette and B = mass of oven dried briquette DETERMINATION OF ASH CONTENT The ash content of the produced sawdust briquette was obtained by placing the entire oven dried sample in a silica dish; the mass of the dish and briquette was noted. The dish containing the briquette was placed in muffle furnace and the temperature in the furnace was gradually brought to 440°Ñ - 750°Ñ and held, until pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1345 Innovations (15th – 17th April 2008), Benin City, Nigeria the sample was completely ash. The ash was covered cool in desiccators. Thereafter the mass of the ash was determined and recorded. Equation (3) was used to determine the percentage ash content of the briquette. % Ash content =

C X 100% ……… (3) [9] B

Where C = ash (g) and B = oven dried specimen (g) DETERMINATION OF CALORIFIC VALUE The calorific value of the briquette was obtained by using equation (4). Calorific value (HCV) = 20.0 x (I-A-M) ------ (4) [6] Where A = ash content, M = moisture content and (Hvc) = high calorific value (mJ/kg) RESULTS AND DISCUSSION RESULTS The mass, volume, density, moisture content, ash content and calorific value of each briquette produced is shown in table 2. DISCUSSION DENSITY From table 2,the density of produced briquette ranged from 189.7 to 460.92 kg/m3. It was observed that the density of the samples increased with increase in silica. For example, sample 2 with 5% silica had a of density 213.7 kg/m3 while sample 5 with 20% silica had a density of 426 kg/m3 . ASH CONTENT The ash content of produced briquette ranged from 0.5% to 3.6% (table 2). The Ash content increased also with increase in silica content from table 2 .For example sample 2, with 5% silica had an ash content of 1.1% while sample 5 with 20% silica content was 2.70%. CALORIFIC VALUE From table 2, the addition of silica caused an increase in the calorific value of the briquette. For example sample 1, 3 and 5 with 0%, 10%, and 20% silica had calorific values of 12.32 mJ/kg, 12.48 mJ/kg and12.68 mJ/kg respectively. This showed that the heat retaining ability of the silica also had a positive effect on the calorific value the briquette. It was observed however that a further increase in the silica to 25% in sample 6, the calorific value of the briquette decreased, this may have been as a result of the insufficient sawdust available in the composition. The briquette with optimum calorific value 12.68 mJ/kg was sample 5 having a composition of 60%, 20%, 15% and 15% for sawdust, silica, kerosene and starch respectively COMPARISON OF CALORIFIC VALUE OF PRODUCED BRIQUETTE WITH WOOD AND OTHER AGRO FUEL From table 2, the maximum calorific value obtained for briquette was 12.68 mJ/kg and that for wood was 12.55(mJ/kg). Thus it can be seen that the calorific value of the improved sawdust briquette is higher than that of wood, which means that the produced briquette has a higher heating energy value than wood. From table 2, it was observed that sawdust briquette had an optimum calorific value of 12.68mJ/kg, while from table 3, [6], that for other agro materials were, Alfalta straw 9.2mJ/kg, coconut shell 10.05mJ/kg, maize stalks 9.1mJ/kg, maize cobs 9.45mJ/kg, rice husk 7.65mJ/kg. Thus it was observed that the produced sawdust briquette had a higher calorific value than these agro materials, showing the competitiveness of its calorific value in pressed fuel marketability. COMPARISON OF ASH CONTENT VALUE OF PRODUCED BRIQUETTE WITH WOOD AND OTHER AGRO FUEL From table 2, the ash content obtained for that of sawdust briquette was 2.7% and that of wood was 0.76%, thus it was observed that sawdust briquette had a higher ash content compared to wood, meaning it burnt well and had a better heat energy value. It was also observed from table 2 and 3 that the produced briquette ash content compares favourably with other agro fuel. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1346 Innovations (15th – 17th April 2008), Benin City, Nigeria CONCLUSION In conclusion, the volume of sawdust generated in Nigeria, particularly in the southern part is quite high. The utilization of these wastes by converting to a high-grade solid fuel with addition of silica and kerosene have resulted in improved calorific value .The sample with the highest calorific value of 12.68mj/kg was found to be briquette with percentage composition of 60% sawdust, 20% sand, 5% kerosene and 15% starch. This produced briquette calorific value was found to be higher than that of wood and some agro waste. It is recommended that other materials be explored as additives in addition to sawdust for briquette production in other to investigate its effect on its energy and heat value REFERENCES (1)

(2) (3) (4) (5) (6) (7) (8) (9)

J.O Osarenmwinda and A.O.A Ibhadode (2000), Determination of the optimum mix of sawdust and coal dust as fuel. Journal of the Nigerian Institution of Production Engineers. Vol.5, No 2 pp 30 – 38. O. Adegoke, (1999), A preliminary investigation sawdust as high grade fuel, Nigeria journals of Renewable energy (NJRE), (1 & 2) 102-107. B .Kjellstrom, .(1981) Characteristics of Some types of Agricultural Resideues for use Fuel in Down Draft Gasifier: A literature Survey. The Beijier Institute, Stockholm I .Lardionios, and A. Klundert, A (1993), Organic Waste: Options for small-Scale Resource Recovery. WASTE Consultants. The Netherlands. K.K Jacob,N.M Simon, M.Jonathan, N.S Canon, and E. Wanyongi, E. (2005), Recycling Waste into Fuel Briquettes,. Agriculture Development, FAO CORPORATE Document REPOSITORY (1985) The briquette of agricultural waste for fuel. G. Bernard, The use of Agricultural Residue as fuel AMBIO volume XIV number 4-5 1985.. G. Barnard. and Kristoferson, L. Agricultural Restidues as fuel in the third world Earthean Ensergy Information Programme, Technical Report N0. 4 Annual book of ASTM Standards ASTM D 2974-87. Standard test methods for moisture, Ash, and organically matter of peat and other organic soils.

TABLE 1: COMPOSITION OF BRIQUETTE MIXTURE Material PERCENTAGE MIXTURE IN VOLUME Used SAMPLE 1 SAMPLE 2 SAMPLE 3 SAMPLE 4 Sawdust 80% 75% 70% 65% Sand 0% 5% 10% 15% Kerosene 5% 5% 5% 5% Starch 15% 15% 15% 15%

SAMPLE 5 60% 20% 5% 15%

SAMPLE 6 55% 25% 5% 15%

Table 2: The mass, volume, density, moisture content, ash content and calorific value of each briquette produced Briquette Briquette Briquette Briquette Moisture Ash content Calorific value Sample Mass(Kg) Volume(m3) density (Mj/Kg) content(%) (%) kg/m3 1 2 3 4

0.1074 0.1210 0.1378 0.1512

0.0005661 0.0005661 0.000532 0.000532

189.70 213.7 259.00 284.2

37.9 36.6 35.9 34.8

0.5 1.1 1.70 2.30

12.32 12.46 12.48 12.58

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2nd International Conference On Engineering Research & Development: 1347 Innovations (15th – 17th April 2008), Benin City, Nigeria 5 6 Wood (Control)

0.1930 0.2088 0.1397

0.000453 0.000453 0.0005661

426.05 466.92 246.77

33.9 33.3 36.5

2.7 3.60 .0076

12.68 12.62 12.55

TABLE 3: Calorific value and ash content of various fuels [6] Material Ash content % Calorific value (mj/kg) Alfalta straw 3.0 9.2 Coconut shell 0.4 10.05 Maize stalks 3.2 9.1 Maize cobs 0.75 9.45 Rice husk 2.0 7.65

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2nd International Conference On Engineering Research & Development: 1348 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD08281) AIR POLLUTION IN BROLL ISLAND 1

Ukpebor, E. E, 2,Igbafe, A.I., 3Obahiagbon K. O. and 3Aluyor, E. O. Air Pollution Research Group, Chemistry Department, University of Benin, Benin City. 2 Atmosphere and Energy Research Group, Department of Chemical Engineering, Faculty of Engineering, University of Benin, Benin City. 3 Department of Chemical Engineering, Faculty of Engineering, University of Benin, Benin City. 1

In Nigeria, about 70% of atmospheric burden evolves from vehicular emissions. However, it is anticipated that this observation might not hold for islands based on their peculiar nature and characteristics. In this preliminary study, the ambient dose of NO2, CO, and TSP were measured as a basis for assessment. NO2 and CO samples were collected and analysed using an electrochemical method, while the TSP was measured using an optical method. Sampling was done between December 2007 and February 2008 (dry season over the study region) and samples were collected at a height of about 2.0 mAGL at each of the sampling sites. Relatively, no significant loadings of all the pollutants were recorded. However, spatial variations in the CO and TSP distributions were found to be statistically significant (p>0.5). The principal component analysis (PCA) identified emissions from domestic sources and flared gases as been a dominant contributor.

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2nd International Conference On Engineering Research & Development: 1349 Innovations (15th – 17th April 2008), Benin City, Nigeria

TECHNICAL SESSION 9B: CONSTRUCTION AND STRUCTURES

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2nd International Conference On Engineering Research & Development: 1350 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08025) MAINTENANCE OF ROADS IN NIGERIA: A NECESSITY FOR SUSTAINABLE DEVELOPMENT

J.O. Aribisala and O.M. Ogundipe Civil Engineering Department, University of Ado-Ekiti, Nigeria. [email protected], 08033867536. ABSTRACT Most of our roads in Nigeria are in deplorable state, thus causing traffic congestion, accidents and consequently deaths, hence the need for routine, periodic and emergency maintenance. This paper looks at road maintenance as ingredient for sustainable development. It discusses the causes of road failure and the problems facing road maintenance operations in Nigeria. The need for Organized Private Sector involvement in road construction, maintenance and management was stressed. Lastly, the strategies for the road maintenance and management were discussed. KEYWORDS: Roads,maintenance,management,development.

1.0 INTRODUCTION Road transport has been identified to be the most important out of all the modes of transport, because roads are vital to economic development, as they link remote places, facilitate movement of goods and are cheaper to maintain and run than other modes. The commuters depend on it to access all other modes. An assessment of the roads in Nigeria shows they are in state of disrepair. By the nature of the materials used for construction, it is impossible to design a road pavement which does not deteriorate in some way with time and traffic [1]. This explains the reason why adequate routine and periodic maintenance is required during the design life of the road. The need for maintenance arises where there is loss of structural adequacy and pavement surface deficiencies [2]. Maintenance of existing road pavements may take the form of patching, sealing or resurfacing. Table 1.0 shows the ideal strategies for road maintenance activities. It is necessary to have the sound knowledge of the factors that have caused the pavement distress, before maintenance work is proposed.

Table 1.0: Ideal strategies for road maintenance Maintenance Prevent Correct Minor Construct Strengt rehabili ive ive ion hening tation mainte mainte nance nance Source: (3) Typical wearing courses need to possess the following characteristics (i) high resistance to deformation; (ii) high resistance to fatigue and the ability to withstand high strains; (iii) sufficient stiffness to reduce stresses in the underlying layers to acceptable levels; (iv) high resistance to environmental degradation i.e. good durability; (v) low permeability to prevent the ingress of water; (vi) good workability to allow adequate compaction during construction; (vii) sufficient surface texture to provide good skid resistance in wet weather and; (viii) predictable performance [3]. The road surfacing requires maintenance, whenever it is lacking in any of these characteristics mentioned above. Therefore, this paper looks at road maintenance as a necessity for sustainable development. 2.0 SUSTAINABLE ROAD TRANSPORT SYSTEM pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1351 Innovations (15th – 17th April 2008), Benin City, Nigeria A sustainable transportation system is one that will move the people and goods from one place to the other at reduced cost with such trip experiencing minimal/no hitch, without compromising the ability of the future generations to meet their own transport needs. The followings are essential factors in a sustainable transportation system (i) access to people, places, goods and services; (ii) community building (iii) health and safety of the people; (iii) pollution control; (iv) efficient land and resource use and; (iv) economic viability [4]. Proper road maintenance contributes to reliable transport at reduced cost, as there is a direct link between road condition and vehicle operating costs (VOC). An improperly maintained road can also represent an increased safety hazard to the user, leading to more accidents, with their associated human and property costs. The essential factors needed for sustainable transportation system could be achieved through periodic and routine maintenance of road facilities. The results of inadequate maintenance of roads have been identified by [5] to include (i) increase in vehicle operating cost; (ii) high cost of production, which is a result of higher freight cost, resulting from high vehicle operating cost; (iii) safety hazards to highway and road users, evident in high rate of accidents, leading to human and material losses and (v) lack of comfort and other in conveniences in transportation. Inadequate maintenance without any doubt impacts negatively on the economy. Table 2.0 shows the periodic road traffic accident rates for Nigeria between the year 1990 and 2004.

Period

1960-1969 1970-1979 1980-1989 1990-1999 2000-2004

Table 2: Periodic road accident rates for Nigeria Severity rate per 100 RTA Killed Injured 13 70 22 72 32 89 41 111 49 114 Source: [6]

The poor state of roads is one of the major causes of road accidents. Table 3.0 shows the causative factors of road accidents in Ekiti-State between January 1999 and December 2003. The table indicates that road defects account for most of the road accidents. Table 3.0: Causative factors for road accidents in Ekiti-State Environmental Mechanical Human Hazard Failure error Peri Road Ni Poor Overl Stati Spee Ot od Defe ght Weat oad/ onary d/ her cts Tra her failur Vehi Overt s vel e cle aking Jan- 19 03 02 08 02 27 03 Dec 199 9 Jan- 37 02 01 02 05 19 Dec 200 0 Jan- 34 09 04 36 13 34 01 Dec 200 1 pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1352 Innovations (15th – 17th April 2008), Benin City, Nigeria JanDec 200 2 JanDec 200 3 Tota l

40

13

-

43

-

56

04

34

13

04

25

09

29

-

164

40

11

114

29

165

08

Source: [7] 3.0 CAUSES OF ROAD FAILURE It will be most appropriate to identify why most of our roads fail as it will give us an insight into how routine and periodic maintenance on our roads could prolong the life of the roads, lower operating cost and promote safety and efficiency. The following have been identified as causes of road failure: fatigue, shoddy workmanship [8]. Other causes include among others, disposal of solid wastes into drainage, inadequacies of construction materials, lack of maintenance and unwholesome practices by the people. Fatigue: Fatigue is the phenomena of repetitive load-induced cracking due to a repeated stress or strain level below the ultimate strength of the material [9]. This results from the use of the road surface over time. It usually manifests in cracks, potholes, etc. Periodic maintenance of the road surfaces such as asphalt overlay remedies fatigue failure of roads. Shoddy workmanship: Unethical practice on the part of contractors is a major cause of road failure. This is usually the result of awarding road contract to politicians who have no knowledge of road construction. They normally see such contracts as their own share of the government largesse. In Nigeria people see public office as an opportunity to get rich [10]. Diversifying processes to accommodate the private sector initiatives will reduce the incidence of corruption [10]. Disposal of solid wastes into drainage: Lack of functional drainage causing water to settle on the road results in road failure. This arises from indiscriminate dumping of refuse into the drainage, therefore preventing the free flow of water. The water finds its way to the surface thus penetrating the pavement and causing failure Use of unsuitable materials: Suitable materials are the ones that are acceptable for use in road works i.e. materials that conform to specification. The use of materials that do not conform to specification could also be the cause of road failure. Such practices could be checked, if the government employs the services of consultants of proven integrity, who would not allow the contractors to go contrary to the specification. Unwholesome practices by the people: It is not uncommon to see irate youths or protesters burning tyres and other combustible materials on the paved roads during protests. This results in the weakening of such spots and later manifests as potholes. Lack of maintenance: This is the main thrust of this paper. Our roads had suffered from the lack of maintenance culture in Nigeria. Most roads fail to function throughout their design life of say 20 years for laterite-based bituminous roads and 30 years for stone-based bituminous roads, because routine and periodic maintenance are not carried out to counter occurrences that could result in the structural failure of the pavements. Adequate maintenance will make the roads to function throughout their lifespan, thus reducing the cost of repair of roads. All the highlighted causes could be prevented by putting in place functional maintenance agencies that respond to the maintenance needs of the roads. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1353 Innovations (15th – 17th April 2008), Benin City, Nigeria 4.0 PROBLEMS FACING ROAD MAINTENANCE OPERATIONS AND SOLUTION Road maintenance operations in Nigeria are hindered by a number of factors. These factors include: (i) insufficient funding; (ii) shortage of manpower with requisite skills and qualification; (iii) poor management capability/framework; (iv) poor utilization of available resources; (v) poor policy environment and (vi) undue politicization of technical issues [11]. All these problems often result due to the sole involvement of government at the federal, state and local levels in the construction, maintenance and management of roads. Insufficient funding: Most of our roads are characterized by failure of different types, despite the fact that they enjoyed the largest share of funds allocation to the transport sector since independence [12]. Given the very poor state of the road network, it is evident that the normal annual budgets of the three tiers of government in the country cannot address the problem [13]. Insufficient fund has been identified as the major factor affecting infrastructural development in Nigeria, hence the need for alternative source of funding [10]. In 2008 budget, the Federal Government of Nigeria proposed 1.89 trillion naira for Federal ministries, departments and agencies. Out of this sum 634.2 billion naira was earmarked for capital expenditure [14]. Table 4.0 shows the analysis of spending proposed for ministries, departments and agencies in 2008 budget. Table 4.0: Proposed budget for Ministries, Department and Agencies in 2008 budget Payroll N 779.3 billion Overheads N 267.6 billion Capital Expenditure N 634.2 billion Consolidated Revenue Fund charges excluding N 212.5 billon debt charges Source: [14] The sum of 94.34 billion naira was proposed for the transport sector out of the capital expenditure. Table 5.0 shows the breakdown of allocation to all modes of transportation. Table 5.0: Fund proposed for transport sector in 2008 budget Fund proposed Modes of Transportation for capital expenditure Road Transport N 73.1 billion Survey, Mapping and Geo-Information N 6.02 billion activities Water Transport N 6 billion Air transport N 9 billion Source: [14] Table 5.0 clearly indicates that the road transport sector enjoys the major share of fund for transport sector, yet there is no significant improvement on the conditions of our roads. Sourcing for funds outside the budget will help the situation Shortage of manpower with requisite skills and qualification: This is another problem facing maintenance operations. The unavailability of skilled workers for maintenance operations results in shoddy workmanship and subsequently failure of the roads. The contractors should be made to have required technical staff before they are awarded road contracts. Poor management capability/framework: This is a major problem in Nigeria context. Poor management on the part of government, the road maintenance agencies is not helping the nation. Quick identification of pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1354 Innovations (15th – 17th April 2008), Benin City, Nigeria failed areas or areas of imminent failure and implementation of repairs will help prevent the road from further deterioration and reduce cost of maintenance. Poor utilization of available resources: It is important that maintenance works are prioritized. This is not always the case in Nigeria, as politicians (heads of governments) would prefer to release fund for the construction or rehabilitation of roads in their constituency, towns, etc., not minding other roads in deplorable states, which are critical to the country’s economy. Poor policy environment: Maintenance operations have not been left out of the problem resulting from lack of continuity of government. New government would want to pursue his/her dream, abandoning the works of previous government. Another problem with government policy is implementation. Most policies only exist on paper. A good policy environment is needed for unhindered and effective maintenance operations. Undue politicization of technical issues: The intrigues of politics have over the years resulted in poor planning, inadequate and untimely funding and lack of indigenization policies for the road sector [15]. All these affect maintenance operations, making failed roads to deteriorate further and bringing undue hardship on the road users. 5.0 STRATEGIES FOR THE MAINTENANCE AND MANAGEMENT OF ROADS IN NIGERIA Since road transport is critical to the development of any nation, it is important that road maintenance and management are handled as matters of utmost concern. The following are proposed as ways of achieving desired result in the maintenance of our roads: Organized Private Sector (OPS) involvement: From independence up-till date, the construction, maintenance and management of roads has been the responsibilities of government at the three levels. This has not helped the nation in any way, as the roads condition is getting worse. Therefore, it is not out of place to allow the Organized Private Sector (OPS) participate in the construction, maintenance and management of roads. Private sector participation need be encouraged through concession contracts for high performance highways. A typical example was the roundabout projects in Ekiti-State. In the arrangement, the banks agreed to pay for the construction of the roundabout in return for the erection of their signage within the roundabouts to advertise their banks for five years, after which they may renegotiate with the government. Establishment of road funds: Road funds refer to funding road maintenance project separately from government budgetary allocations. Such funds may be from the following sources: (i)vehicle licensing fees; (ii) vehicle registration fees; (iii)tax on haulage trucks; (iv) road cutting fees; (v)collection from toll gates; (vi) statutory contribution from the federal government and from occasional gains as excess earnings from crude oil sales; (vii) transportation impact fees- collectable from property developers adjacent to major highways; (viii) general taxation; (ix) fuel levy and (ix) contributions from the private sector-statutory contributions as percentage of earnings of companies, different from normal taxation. Establishment of road agencies: Another way the desired result could be achieved in the maintenance of roads is the establishment of agencies saddled with the responsibilities of carrying out routine, periodic and emergency maintenance. The establishment of Federal Road Maintenance Agency (FERMA) by the federal government of the Federal Republic of Nigeria and other road maintenance agencies like Ogun-State Road Maintenance Agency (OGROMA), Ekiti-State Road Maintenance Agency (EKROMA), etc. by the state governments is a welcome development. However, it is unfortunate that the agencies have lost focus; FERMA now handles more of repairs/rehabilitation work leaving out maintenance works which is the reason for their establishment. EKROMA now handles construction work. This idea has jettisoned the reasons for setting up these agencies. They should be charged to pay more attention to maintenance works. The agencies should be more proactive in their operations, hence the need for government and private organization to provide them with equipment and funds to enable them discharge their functions efficiently and effectively. The states that have not established such bodies should be encouraged to do so. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1355 Innovations (15th – 17th April 2008), Benin City, Nigeria Community participation: A sustainable road transport system should ensure community building and enhance the peoples’ quality of life. It is important that the public participate in the roads decision making. This ensures their interests are taking into consideration. This will as well make them to be well informed of the need to make the road drainage in their area free of debris for easy flow of water. Such participation could be by mandating the community to form associations or groups which will be directly in charge of the maintenance works and they may contribute counterpart fund. Non-politicization of road contracts: Politicization of road contracts should be discouraged. Road consultancy should be awarded to professional civil engineers/consultants that know the rudiments of construction, maintenance and management of roads. Road construction companies should have proof of qualified technical staff before they are awarded contracts. This will go a long way in addressing the problem of shoddy workmanship.

6.0 CONCLUSION This paper has highlighted the need for maintenance of roads in order to keep them functional throughout their design life. The causes of road failure were discussed to include fatigue, shoddy workmanship, etc. The problems facing maintenance operations in Nigeria were examined and the strategies for the maintenance and management of roads include Organized Private Sector involvement, establishment of road funds and road agencies, etc. Since good road network is one of the determinants of the socioeconomic prowess of a nation, state or community, it is important that all stakeholders vis-à-vis government, private sector and the community work together to attain the sustainable level in the construction, maintenance and management of roads. REFERENCES [1] TRL, “Overseas Road Note 31: A Guide to Structural Design of Bitumen-Surfaced Roads in Tropical and Sub-Tropical Countries” Transport Research Laboratory, Crowthorne, United Kingdom, 1993. [2]Fadaka B., “Review of Highway Maintenance Strategies and Practices: The Global Experience” Proceedings of National Workshop on Highway Maintenance Management, 14-16th October, (2003) Pp 96115. [3] TRL, “Overseas Road Note 19: A Guide to the Design of Hot MiX asphalt in Tropical and SUB-Tropical Countries” Transport Research Laboratory, Crowthorne, United Kingdom, 2002. [4] OECD,“Towards Sustainable Transportation: Sustainable Transportation Principles” QECD International Conference, Vancouver, Canada (1996) Pp 1-7. [5] Oguntuase A.M., “Enhancing Public-Private Sector Participation through Effective Contract Administration for Road Construction and Maintenance” Proceedings of the 4th National Civil Engineering Conference of the Nigerian Institution of Civil Engineers, Abuja, (2006) Pp 19-27. [6] Yerima M. and Egwurube J.,“Road Safety: The Nigerian Approach” 15th International Safe Communities Conference, University of Cape Town, South Africa, 2006. [7] Federal Road Safety Commission, Ekiti-State Command. [8] Osikoya M.K., “Local Practices in Highway Maintenance” Proceedings of National Workshop on Highway Maintenance Management, 14-16th October, (2003) Pp 140-148. [9]Yoder E.J. and Witczak M.W., “Principles of Pavement Design” John Wiley and Sons Inc. New York, Second Edition, 1975. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1356 Innovations (15th – 17th April 2008), Benin City, Nigeria [10]Aribisala J.O., “Enhancing Civil Engineering Infrastructural Development and Project Quality through Community Participation” Proceedings of the 4th National Civil Engineering Conference of the Nigerian Institution of Civil Engineers, Abuja, (2006) Pp 40-46 [11] Adebisi O., “A Framework for Highway Maintenance Management in Nigeria” Proceedings of National Workshop on Highway Maintenance Management, 14-16th October, (2003) Pp 1-9. [12] Sekibo A.S., “Reform of Transport Sector in Nigeria” Speech delivered by the Honourable Minister of Transport, Federal Republic of Nigeria at the Financial Bid Opening of Port Harcourt Terminals “A” and “B”, Abuja, 2005. [13] Adeniji K., “Strategic Options for Overcoming Resource Constraints in Highway Maintenance.” Proceedings of National Workshop on Highway Maintenance Management, 14-16th October, (2003), Pp 1019. [14] Yar’Adua U.M., “2008 Budget Speech” Delivered by His Excellency the President of Federal Republic of Nigeria at Joint Session of the National Assembly, November 8, 2007. [15] Adeniran M.S., “Highways: Challenges of Maintenance and Development” A Technical Paper Presented at the meeting of Nigerian Society of Engineers, Ado-Ekiti Branch, 5th November, 2007.

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2nd International Conference On Engineering Research & Development: 1357 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08056) EFFECT OF COMPACTIVE EFFORT ON LIME TREATED BLACK COTTON SOIL USING BAGASSE ASH AS ADMIXTURE

Osinubi, K.J.1, Ijimdiya, T.S.2, and Nmadu, I.3 e-mail: [email protected] (08035866860) (Corresponding author) 1,2 Department of Civil Engineering, Ahmadu Bello University, Zaria. Nigeria. 3 Federal Ministry of Transportation (Works) Field department, Kaduna. Laboratory studies to investigate the effect of compactive effort on the engineering properties of lime treated black cotton soil using Bagasse Ash (BA) as admixture was carried out. Black cotton soil is classified as A7-6 or CH in accordance with the AASHTO and the Unified Soil Classification Systems respectively. The results obtained show that the moisture density relationship follows a trend of increasing optimum moisture content (OMC)/decreasing maximum dry density (MDD) at the SP, WAS and MP compactive efforts, respectively. California bearing ratio (CBR) values obtained for all compactive efforts are lower than the 80% CBR criterion recommended by the Nigerian General Specification (1997) for untreated base course materials. On soaking however, only samples compacted at MP effort met the criteria for sub base materials with the peak value of 34% obtained at 4%lime/ 4%BA. The peak durability value for resistance to loss of strength for SP, WAS and MP compactive energy levels are 32.5% at 6% lime – 6%BA, 62% at 6% lime – 8% BA and 63.5% at 6% lime – 8%BA, respectively. KEYWORDS: Compactive efforts, maximum dry density, California bearing ratio.

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2nd International Conference On Engineering Research & Development: 1358 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08058) Lime stabilization of black cotton soil using bagasse ash as admixture K.J. Osinubi1, I. Nmadu2 and T.S. Ijimdiya3 E-mail: [email protected] (08035866860) (Corresponding author) 1,3

Department of Civil Engineering, Ahmadu Bello University, Zaria. Nigeria.

2

Federal Ministry of Transportation (Works), Kaduna field Headquarters.

ABSTRACT Laboratory studies to investigate the effect of Bagasse Ash (BA) admixture on the engineering properties of lime treated black cotton soil was carried out. Black cotton soil is classified as A-7-6 in accordance with AASHTO soil classification system. Bagasse ash is obtained from burning the fibrous residue from the extraction of sugar juice from sugarcane. The results obtained show that the moisturedensity relationship follows a trend of increasing optimum moisture content (OMC)/decreasing maximum dry density (MDD) at the standard Proctor compaction energy. California bearing ratio (CBR) values obtained are lower than the 80% CBR criterion recommended for untreated base course materials. The peak CBR value obtained was 30% at 8 % lime / 4 %BA. This value meets the recommended criterion for subgrade materials. The unconfined compressive strength (UCS) at 7 days is lower than the 1034.25kN/m2 evaluation criterion recommended by TRRL (1977) for adequate lime stabilization. On the basis of the soaked CBR and durability values, it is recommended that black cotton soil can be stabilized for road construction using a 8 % lime/ 4 % BA blend of admixture at standard Proctor compaction. However, due to the relative high cost of lime and large quantity that shall be required to achieve stabilization, further study and consideration should therefore be given to the use another additive such as cement to augment and lower the percentage of lime and thus the cost of stabilization. KEYWORDS: Lime, bagasse ash, optimum moisture content, maximum dry density, unconfined compressive strength.

INTRODUCTION Expansive soil is the term generally applied to any soil that has a potential for shrinking and swelling under changing moisture conditions. The soil is basically found in semi-arid and arid regions of the tropical/temperate zones usually characterized by marked dry and wet seasons with low rainfall, poor drainage and great heat. The Nigerian expansive soil is formed from basic igneous rock parent material [1]. The name black cotton soil is derived from the fact that cotton plant thrives well on it. The black cotton soils of northeastern Nigeria derive their origin from basalts of the upper Benue trough which covers a wide area extending north and east of the Jos Plateau and from quaternary sediments of lacustrine origin from the Chad basin consisting mainly of shales, clay and shaly sediments [2]. Specifically, Nigerian black cotton soils are formed from the weathering of shaly and clayey sediments and basaltic rocks. According to Ola [3] the Nigerian black cotton soil contains more of the montmorillonite clay mineral with subsequent manifestation of swell properties and expansive tendencies. The soil is found in the north eastern parts of Nigeria, Cameroon, Lake Chad Basin, Sudan, Ethiopia, Kenya, South Zimbabwe and other Eastern African countries, India, Australia, South Western U.S.A., South Africa and Israel [4]. Its color is dark- grey to black probably due to iron and titanium compounds present. It is classified as an A-7-6 soil according to the AASHTO [5] classification system and has index properties that indicate an inadequacy for most practical engineering use. Expansive soils cause more damage to structures than any other natural hazard including earthquakes and floods [6]. The amount of damage caused by expansive soils is pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1359 Innovations (15th – 17th April 2008), Benin City, Nigeria alarming. In Nigeria, the damages caused by expansive soils are not documented; however, in the United States, it has been estimated that losses from expansive soils exceed two billion dollars annually [7]. Bagasse is the fibrous residue obtained from the extraction of sugar juice from sugarcane. When burnt, the ash contains a substantial amount of amorphous silica that reacts with lime [8, 9, 10 and 11]. This ash is considered as waste in Nigeria and is disposed in an environmentally debilitating manner. Sugar cane is readily available in most parts of the country although due to poor agricultural practices, it is seasonal. LOCATION OF STUDY AREA The soil samples were obtained from Biu in Adamawa State which lies on latitude 10o 15’N and longitude 11o00’E. The bagasse ash was collected at Makarfi in Kaduna State. All tests carried out on the natural and treated soil was in accordance with specifications [12 and 13]. The oxide composition of the soil used is shown in Table I. MATERIALS AND METHODS Bagasse Ash The bagasse used for the study was sourced locally and ashed by open air burning. The resultant ash was carefully sieved through 0.075mm aperture sieve to remove unwanted materials. A sample of the ash was analyzed for its oxide composition; the results are summarized in Table II. Lime Hydrated lime was purchased locally from accredited suppliers.

DISCUSSION OF RESULTS Atterberg Limits Fig. 1 shows the variation of liquid limit of lime treated soil with BA content. The results indicate a decrease in liquid limit from 73 % for the natural soil to a value of 56 % for soil treated with 8 % lime/4 % BA mixture (i.e., 23 % decrease in liquid limit). The overall decrease in liquid limit could be attributed to the flocculation and aggregation of the clay particles and the accompanying reduction in surface area and increase in strength. Fig. 2 shows the variation of plastic limits of lime treated black cotton soil with baggase ash contents. There was an increase in plastic limit from 31 % at 6 % lime/ 0 % bagasse ash to a peak value of 42 % at 6 % lime/ 6 % bagasse ash. This alteration of soil character probably occurred due to bi-valent calcium ions supplied by the lime replacing less firmly attached monovalent ions in the double layer surrounding the clay particles. This according to O’Flaherty [14] tends to decrease the thickness of the double layer and to depress the zeta potential (i.e., a measure of the effectiveness of the particle negative charges in repelling a second particle) thereby causing flocculation and agglomeration. However, the increase in the plastic limit could partly be due to the highly plastic nature of lime and perhaps due to the increase in the amount of fines content. The drop in the plastic limit at higher doses of BA content may be due to the presence of excess CaO from BA admixture and can be compared to the phenomenon of lime fixation point in which the clay surface is said to be covered with a monolayer of lime.

Compaction Characteristics Fig. 3 shows the variation of maximum dry density (MDD) of lime treated black cotton soil with bagasse ash. The MDD of the untreated black cotton soil was 1.40 Mg/m3. The MDD decreased on addition of lime to a value of 1.41 Mg/m3 at 2% lime content. It was observed that as the lime content increased, the MDD decreased. However, on inclusion of bagasse ash there were slight improvements in the MDD which peaked at a value of 1.40 Mg/m3 at 2 % lime/ 4 % bagasse ash content. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1360 Innovations (15th – 17th April 2008), Benin City, Nigeria The decrease in MDD with addition of lime is probably due to the presence of larger quantities of lime with lower specific gravity occupying larger spaces within the soil lattice thereby decreasing the MDD [3, 15 and 16]. Fig. 4 shows the variation of OMC for lime treated black cotton soil admixed with bagasse ash contents. At 2 % lime content the OMC was 24 % and as the lime content increased the OMC also increased which gave a value of 28 % at 4 % lime/8 % BA content. The increase in OMC agrees with previous research work by Osinubi and Katte [17] that attributed the increase to the amount of water required for pozzolanic reactions to take place.

Strength Characteristics California bearing ratio Fig. 5 shows the variations of soaked C.B.R of lime treated black cotton soil with BA content. At 2 % lime/ 0 % BA content, the CBR obtained was 8 %. At 4 % lime/6 % BAC a peak value of 20 % CBR was obtained. This showed a great improvement. The reason for the great improvement in the strength could be due to adequate amounts of calcium required for the formation of calcium silicate hydrate (CSH), which is the major element for strength gain. It has been recommended that the CBR value of 180 % should be attained in the laboratory for cement-stabilized material to be constructed by the mix-in-place method [18]. Although, the lime treated black cotton soil admixed with bagasse ash do not meet the minimum criteria as specified [18] for materials suitable for use as base course material of not less than 30% C.B.R determined at MDD and OMC, the treated material can be used as a suitable sugrade material, hence it attains a CBR value of 20 % as against the 15 % requirement criterion [18]. Unconfined compressive strength The relationship between the unconfined compressive strength (UCS) and lime/BA blend contents for the BSL compactive effort at 7 days curing period is shown in Fig. 6. It is observed that the UCS of the lime treated black cotton soil with bagasse ash increased from 183 kN/m2 at 0 % lime/ 2 % BA contents to a peak value of 298 kN/m2 at 8 % lime/2 % BA contents. Further increase in bagasse ash led to a decrease in the UCS. Early increase in UCS values observed between 2 and 4 % BA contents could be attributed to ion exchange at the surface of clay particles as the Ca2+ in the stabilizer reacted with the lower valence metallic ions in the clay microstructure which resulted in agglomeration and flocculation of the clay particles.

CONCLUSIONS  



The natural soil (black Cotton) obtained along Gombe – Biu road in the North Eastern Nigerian falls under the A–7–6 [5] classification. The Lime/BA blend reduced the liquid limit from 73 % to 56 % at 8 % lime/4 % BA and increased the plastic limit of the natural soil from 25 % to 42 % at 8 % lime/6 % BA. This resulted to an almost 70 % drop in the plasticity index to 15 % at 8 % lime/4 % BA. The unconfined compressive strength (UCS) of the lime/BA treated soil did not improve considerably when compared with the values obtained for the natural soil as shown in Fig. 6. The increase recorded was marginal at 7 days curing. The UCS obtained however is less than the criterion of 1034.25KN/m2 for lime-stabilized soils recommended by Road Note 31 [19]. However, the lime treated black cotton soil admixed with bagasse ash could be used as a suitable subgrade material.

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2nd International Conference On Engineering Research & Development: 1361 Innovations (15th – 17th April 2008), Benin City, Nigeria From the results of this study, it is recommended that the optimum lime/baggase ash admixture of 8 % lime/4 % bagasse ash could be used to stabilize black cotton soil for use as a road subgrade as its benefits include greatly reducing the cost of stabilization and reducing the adverse environmental impact of baggase ash waste.

REFERENCES [1]

Plait, R.M (1953). “determination of swelling pressures of black cotton soils – A method” Proc. Of the Third International Conference on soil mech. and foundation. Engrg. Vol.1pp 70

[2]

NBRRI, (1983). Engineering Properties of Black Cotton Soils of Nigeria and Related Pavement Design. Nigerian Building and Road Research Institute, Research Paper No., 1 –20.

[3]

Ola, S.A (1983a). “The Geotechnical Properties of Black Cotton Soils of North Eastern Nigeria”. In S.A. Ola (Editor). Tropical Soils of Nigeria in Engineering Practice, A.A. Balkema, The Netherlands, Rotterdam, pp 85 101, 155-171.

[4]

Ola, S.A (1978). The geology and geotechnical properties of black cotton Soils of north eastern Nigeria, Engineering Geology, Vol. 12, 375-391.

[5]

AASHTO (1986): Standard Specification for transportation Materials and Methods of Sampling and Testing, 14th Edition. Am. Assoc. of State Hwy. and Transp. Officials, Washington, D.C. Jones, D. and Holtz (1973). “Expansive soils Hidden Disaster”. J. of Civil Engineering, Vol. 43, pp. 54.

[6]

[7]

Chen, F.H. (1988): Foundation on Expansive Soils, American Elsevier Science Publ., NewYork.

[8]

Cook, D J and P Suwanvitaya (1982) Properties and behavior of lime-rice husk ash cements. UNCIV Report No 8208. University of New South Wales, Australia.

[9]

Mehta, P K (1979). The chemistry of cements madefrom rice husk ash. Proc. of Workshop on Production ofCement-Like Materials from Agro-Wastes UNIDO-ESCAP-RCTT-PCSIR. Peshawar, Pakistan.

[10]

Osinubi K.J. and Alhaji, M.M. (2005). “The potential of bagasse ash as a pozolana”. Proc. 4th Nigerian Materials Congress, NIMACON 2005, November, Zaria. p. 41 - 45

[11]

Osinubi, K.J. and Stephen, T.A. (2005). “Economic utilization of an agro- indusrial waste – Bagasse ash.” Proc. 4th Nigerian Materials Congress, NIMACON 2005, November, Zaria. p. 36 - 40

[12]

BS 1924 (1990): Methods of Test for Stablizied Soils. British Standarads Institute, London.

[13]

BS 1377 (1990): Methods of Testing Soils for Civil Engineering Purposes. StandardsInstitute, London

British

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2nd International Conference On Engineering Research & Development: 1362 Innovations (15th – 17th April 2008), Benin City, Nigeria [14]

O’Flaherty, C.A. (1974). Highway Engineering Vol. 2 Edward Arnold, London, U.K.

[15]

Lees, G., Abdelkader, M.P. and Hamdani, S.K. (1982).”Effect of clay fraction on some mechanical properties of lime-soil mixtures”. J. Inst. Highway Engrg. Vol. 29, No. 11, pp. 2 – 9.

[16]

Osinubi, K.J. and Stephen, T.A. (2007). Influence of compactive efforts on bagasse ash treated black cotton soil. Nigerian Journal of Soil and Environmental Research. Vol. 7, pp. 92 – 101.

[17]

Osinubi, K.J. and Katte, V.Y. (1997). “Effect of elapased time after mixing on grain size and plasticity characteristics 1”. Soil-Lime mixes, NSE Technical Transactions Vol. 32, No.4 65-77.

[18]

Nigeria General Specification (1997): Roads and Bridge works. Federal Ministry of Works, Abuja, Nigeria.

[19]

TRRL (1977)). A Guide to the Structural Design of Bitumen – surface roads in Tropical and Subtropical countries, road Note 31, Transport and Road Research Laboratory, HM.S.O., London.

Table I: Oxide composition of Black Cotton Soil Oxide

(%)

CaO

-

SiO2

31.01

Fe2O3

4.74

Al2O3

16.19

MnO

0.13

TiO2

1.34

After Osinubi and Stephen (2005) Table II: Oxide Composition (%) of Bagasse Ash Relative to Ordinary Portland cement (OPC). Oxide *OPC (%) Bagasse Ash (%) CaO 3.23 63 SiO2 57.12 20 Al2O3 29.73 6 Fe2O3 2.75 3 Mn2O3 0.11 Na2O + K2O 1 K 2O 8.72 SO3 0.02 2 TiO2 1.10 Loss on Ignition 17.57 2  After Osinubi and Stephen (2005) pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1363 Innovations (15th – 17th April 2008), Benin City, Nigeria * After Czernin 1962.

75 70

Moisture content (%)

65 60 2% lime 55 4% lime 50 6% lime 45 8% lime 40

0

2

4

6

8

Bagasse Ash content (%) Fig. 1:Variation of Liquid Limit of Lime treated black cotton soil with Bagasse Ash Contents

45

% Moisture Content

40

2% lime

35 4% lime 30 25

6% lime

20 8% lime 15 0

2

4

6

8

Bagasse Ash Content (%)

Figure 2:Variation of Plastic imit of Lime treated black cotton soil with Bagasse Ash

Maximum Dey Density (Mg/m 3)

1.42 1.4 1.38 2%

1.36 4%

1.34 1.32

6%

1.3

8%

1.28 1.26

0

2

4

6

8

Bagasse Ash Content(%)

Fig 3:Variation of Maximum Dry Density of lime treated black cotton soil with Bagasse ash Content

30

% O.M.C

28 26 2% lime

24

4% lime 22 6% lime 20

8% lime 0

2

4

6

8 % Bagasse Ash

Fig. 4: Variation of moisture content of lime treated black cotton soil with Bagasse ash content

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2nd International Conference On Engineering Research & Development: 1364 Innovations (15th – 17th April 2008), Benin City, Nigeria 21

C.B.R(%)

19 17

2% Lime

15

4% Lime

13 6% Lime

11

8% Lime

9 7 5 0

2

4

6

8 % Bagasse Ash

Fig. 5 Variation of CBR of lime treated black cotton soil with Bagasse asg as admixture

400

U C S ( K N /m 2 )

350 300 250 200 150 2% Lime

100 50

4% Lime

0 0

1

2

3

4

5

6 7 8 Bagasse Ash Content (%)

6% Lime 8% Lime

Fig. 6: Variation of unconfined compressive strength of lime treated black cotton soil with bagasse ash

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2nd International Conference On Engineering Research & Development: 1365 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD08065) INVESTIGATION ON THE COMPATIBILITY OF CEIBA PENTANDRA AND BOMBAX BUONOPOZENSE FLAKE WITH ORDINARY PORTLAND CEMENT

Badejo, S.O.O.; Baiyewu, R.A; Ademola, I.T; Adeniyi, M.I.; and Areo, O.S. Department of Forest Products Development & Utilization Forestry Research Institute of Nigeria, Jericho, P.M.B. 5054, Ibadan

Flakes of Ceiba pentandra (Araba) and Bombax buonopozense (Bombax) wood were generated using tenoning machine. The flakes were dried up in an open space to attained minimum moisture content of 12%.. The flakes were pre-treated with hot water at 80oc, drained and spread in an open space for air drying. Two variables used includes mixing ratio at three levels (2.0:1, 2.5:1 and 3.0:1) and chemical additive concentration at three levels (2%, 2.5% and 3%) for the board production. The measured materials were thoroughly mixed and spread into a mould of (35 x 35 0.6)cm in dimension, this later subjected to cold press under hydraulic press of pressure 1.2N/mm2. After 24 hours, the replicated homogenous boards were demoulded and stacked for conditioning for 28hours. The boards were cut into samples for various tests including Modulus of Rupture, Modulus of Elasticity, Thickness Swelling and Water Absorption. The statistical analysis adopted was 2 x 3 x 3 factorial experiment in completely randomized design. The result showed that Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) of the boards improved with increase in cement/wood ratio and chemical additive concentration and mixing ratio after 24 hours of water immersion. The reference to the dimensional stability and bending strength of the boards produced from Araba at 3% of additive concentration and 3:1 mixing ratio is fairly suitable for internal construction. Board produced from Bombax at 2.5:1 and (2 – 3%) level of additive concentration are suitable for production of cement bonded flake board. Key words:- Ceiba pentandra, Bombax buonopozense, Modulus of Rupture, Modulus of Elasticity, Water Absorption, Thickness Swelling.

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2nd International Conference On Engineering Research & Development: 1366 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08066) Potentials of Eupatorium odoratum for the production of cement-bonded composite *1

S.O, Badejo; 2R.A, Baiyewu; 1O.N, Amoo-Onidundu; 3B, Ajayi; and 4S.O, Taleat, 1,2and4 Department of Forest Products Development and Utilization, Forestry Research Institute of Nigeria, Jericho, P.M.B.5054. Ibadan. Email [email protected] or Email [email protected] 3 Department of Forestry and Wood Technology, Federal University of Technology, Akure, P.M.B. 704. Akure

ABSTRACT The suitability of Eupatorium odoratum for the production of cement-bonded board was investigated. The boards were produced at nominal density levels of 1000 kg/m3, 1100 kg/m3 and 1200 kg/m3; additive concentration levels of 1%, 2% and 3% and a constant cement/ Eupatorium odoratum ratio (Mixing Ratio) of 2.0:1. The Water Absorption (WA), Thickness Swelling (TS), Linear Expansion (LE), Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) were determined. Effect of the three levels of the board density and additive concentration at a constant mixing ratio on WA, TS, LE, MOE and MOR were investigated. The boards produced were tested according to the American Standard, ASTM D1037 (1978). The result of the mean values obtained for WA, TS, LE, MOE and MOR showed that boards produced at nominal density 1200 kg/m3, additive concentration 3% and mixing ratio 2.0:1 had the best strength and dimensional stability. Based on the result obtained, boards produced from Eupatorium odoratum particles were considered suitable for the production of cement-bonded composite. Keywords: Eupatorium odoratum, Water Absorption, Linear Expansion, Modulus of Rupture and Modulus of Elasticity INTRODUCTION Cement-bonded composite is made from strands, particles or flakes of wood mixed together with Portland cement and additives. They can be manufactured into panel products such as bricks, floor tiles, ceiling boards and other products used in the construction industry. [l]. The inherent excellent properties of cementbonded boards have made them versatile construction materials for roofing, ceiling, flooring, partitioning, cladding and shuttering [2] Cement-bonded particleboard (CBPB) is manufactured mainly from the familiar and proven raw materials – cement and wood particles to which a very small quantity of additives is added to ‘mineralize’ the wood particles. In order to meet future wood product needs, one strategy is to convert various agricultural residues into value-added panel products in combination with Portland cement, an inorganic binder [3]. Some agricultural products have been considered experimentally viable as raw materials for composite boards manufacture at low pace. These include bagasse [4], maize stalk [3] and other non-wood raw materials [57]. In addition to these, research on the use of Eupatorium odoratum as a raw material for cement-bonded board may further expand the scope and the source of suitable raw materials for cement-bonded particleboard in agricultural sub-sector for Nigeria. The use of such raw material for the production of the panel products suitable for use as alternative to sawn timber will increase the industrial and economic base of the national development [8]. Eupatorium odoratum belongs to the family Asteraceae. Its synonym is Chromolaena odorata. It belongs to the group of shrubs of tropical or tender perennials. The common name of Eupatorium odoratum is Christmas bush/siam weed. It is a green house shrub, which bears scented white flowers. It may be planted out at the end of May, but must be lifted before the frost comes. The plant grows to a height of 4-6ft (1.2 – 1.8m.) flowers in August, continuing in bloom for a long while. The spacing is about 36-48” (90-120cm); as a plant, which requires full sun exposure, Eupatorium odoratum pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1367 Innovations (15th – 17th April 2008), Benin City, Nigeria does not tolerate shade but thrives well in open areas. It is a fast growing perennial shrub native to South America and Central America. It has been introduced and has become an aggressive invasive weed in much of tropical Asia, Africa and the Pacific. The plant requires at least 1200mm annual rainfall, but tolerates severe dry season. It is a troublesome weed of open cultivated field, roadside and plantation crops. It is wide spread in West Africa from the coastal fringes of the rain forest to the southern edge of the guinea savannah [9]. The objective of this study is to investigate the potential of Eupatorium odoratum for the production of cement-bonded particleboards. MATERIALS AND METHODS The material (Eupatorium odoratum) was collected from an uncultivated area of Federal University of Technology, Akure, Ondo State. It was later converted into flakes before transported to Forest Products Development and Utilization Department of the Forestry Research Institute of Nigeria where it was grinded into particles using grinding machine. The particles were pre-treated with Hot water at a temperature of 80oC for an hour. This was done in order to remove the water-soluble chemical present in the materials which have the tendency of poisoning the cement thereby inhibiting cement setting or curing of the cement binder. After the hot water treatment, the leachate was drained off; the materials were spread in an open space and air-dried to attain moisture content of approximately 12%. To calculate the moisture content, a quantity of the particles required was first measured on the weighing balance to represent the initial weight. Subsequently, the particles were weighed until the final weight of the particle was measured. At this moisture content, the weight of the sample was uniform. Pretreated particles were bagged using polythene bags before they were used for board formation. The combination of the production variables, (additive concentration and board density at constant ratio) gives a 3 x 3 factorial experiment in a Completely Randomized Design (CRD). According to each treatment combination of the board density, the required quantity of Eupatorium odoratum particles and Portland cement were weighed out and poured inside a bowl. The required chemical additive concentration of Calcium Chloride (CaCl2) and water was measured with a measuring cylinder. This was then poured into the bowl containing the cement and particles, which were thoroughly mixed together by hand. The furnish was hand-formed inside a wooden caul plates wrapped with polythene bag. The mats were then transferred to the hydraulic press and cold-pressed under a pressure of 1.23 N/mm2 for 24hours. After this, the boards were de-moulded and stored inside a well-sealed polythene bags for 28days to achieve further curing of cement. The edges of boards were subsequently trimmed and boards were cut into test specimens and conditioned in controlled environment at room temperature (20oC) and 65±2% relative humidity for 21days. The boards were then tested in accordance with the test procedure stipulated in ASTM D1037 (1978). The Water Absorption (WA), Thickness Swelling (TS), Linear Expansion (LE), Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) properties were all investigated. Data obtained were analyzed using computer software. Analysis of variance was conducted to relate the effects of additive concentration and board density on all the properties tested on the test samples. The interaction of the two factors on these properties was considered. Follow-up analysis was also conducted using Duncan method to compare the effect of observed individual level of each factor of production on board properties examined. Consequently, graphs were used to represent the result obtained for the different relationship between the factors. RESULTS AND DISCUSSION Table 1 contains the mean values of WA, TS and LE, MOE and MOR. With increase in additive concentration and board density, the WA, TS and LE of boards decreased. This observation conformed to the findings of Fuwape [10] and Ajayi [8]. This means that boards produced at the highest levels of board density and additive concentration of 1200kg/m3 and 3% at 2.0:1, were most stable dimensionally as they show highest resistance to WA, TS, and LE when soaked in water. (Fig 1:as a example for WA,TS and LE) In the same vein, from this result (Table1) it was observed that the strength properties were affected by additive concentration and board density. The MOE and MOR of the cement-bonded boards increased as the additive concentration and board density increased. The strongest and stiffest boards were produced at the highest level of board density (1200kg/m3) and additive concentration (3%) as they show greatest improvement at these levels (Fig 2 as an example for MOE and MOR:). The finding agrees with the pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1368 Innovations (15th – 17th April 2008), Benin City, Nigeria work of [11-14]. It is likely that improved bonds quality; dense nature of boards and more additive concentration might have been responsible for the highest strength properties obtained at the levels [11-14]. TABLE 1: The mean values obtained for WA, TS, LE, MOE and MOR of Boards Additiv Nominal Observed WA (%) TS (%) LE (%) MOE e Conc density(kg/mm density(kg/mm (Kg/mm3) 2 2 (%) ) ) 1 1000 1003 30.50±0.0 5.35±0.0 0.43±0.0 2024.0±0.02 2 4 2 1 1100 1102 28.20±0.1 4.97±0.0 0.41±0.0 2307.5±0.08 6 1 1 1

1200

1203

2

1000

1012

2

1100

2

MOR (kg/mm3 ) 2.02±0.0 1 2.53±0.0 0

26.99±0.0 0 28.28±0.0 0

4.76±0.0 0 3.88±0.0 1

0.38±0.6 1 0.40±0.0 1

3452.3±0.00

1103

27.24±0.0 3

2.84±0.0 3

0.37±0.0 1

3567.1±0.00

3.92±0.0 1

1200

1211

3

1000

1002

1100

1111

2.71±0.0 1 3.53±0.0 0 1.39±0.0 1

0.35±0.0 0 0.39±0.0 1 0.36±0.0 2

4123.8±81.6 5 3724.6±0.00

3

26.33±0.0 0 27.62±0.8 2 25.84±0.0 2

5.03±0.0 2 4.75±0.0 0 5.38± .00

3

1200

1208

0.34±0.0 0

4386.4±0.00

23.93±1.6 3

1.39±0.0 1

2924.2±8.17

4021.1±8.16

4.28±0.0 2 3.32±0.0 0

5.64±0.0 2

*Each value is a mean of four replicates ± standard error TABLE 2: Multiple Comparisons for WA, TS, LE, MOE and MOR MOE(N/mm2)

0.36a 0.32b 0.30c

MOR (N/mm2) 3.72a 4.91b 5.77c

0.35a 0.33b 0.31c

3.93a 4.86b 5.62c

3116.54a 3918.68b 43.74.03c

Factors

Levels

WA (%)

TS (%)

LE (%)

Board density

1000kg/m3 1100kg/m3 1200kg/m3

24.00a 22.70b 21.51c

2.92a 2.05b 1.59c

1% 2% 3%

23.74a 22.98b 21.51c

2.89a 2.09b 1.59c

Additive concentration

3245.30a 3813.64b 4350.30c

Means with different alphabets signify that each level of the various production variables is significantly different (p 0.05). Oil is less dense than water and hence it floats on water. Besides, rubber is hydrophobic. Consequently, the absorption of oil by rubber is not hindered by the presence of either fresh water or marine water. 3.3 Effect of Rubber to Oil Ratio on Survival of Fish in Oil Polluted Environment. Fig.5. illustrates the effect of adding different weights of rubber particles of size 0.425mm to aquaria containing fish in water contaminated with oil. The results show only a relatively little change in the survival time (2.5 – 7h) when the weight of rubber to that of oil on the water surface was between 1 and 2.5. However, when the weight of rubber was changed to 3, there was a sharp discontinuity in the curve of survival time-rubber/oil ratio followed subsequently by a much gentler slope. Indeed for a rubber to oil ratio of 3 the survival time was 6,000 h.

Figure 5. Variation of organism survival period with rubber to crude oil ratio. In these aquaria, there was no circulation of air. Therefore the fish depended exclusively on the oxygen dissolved in the water for survival. At low rubber to oil ratios, the oil covering the water surface was largely pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1507 Innovations (15th – 17th April 2008), Benin City, Nigeria continuous since the oil covering the water surface was too much to be adequately absorbed by the added rubber particles. Consequently, fish depended only on the residual oxygen dissolved in water for survival; the continuous oil film prevented replenishment of oxygen from air into the water. Obviously, it is reasonable to argue that the thicker the oil film on the water surface the more difficult it was for oxygen to penetrate and dissolve in the water. As the rubber to oil ratio increased, the thickness of the oil film decreased concomitantly. Hence as the rubber to oil ratio increased to 3, sufficient oil had been absorbed by the rubber particles, thus breaking up the continuity of the oil film and leaving only patches of oil and/or oil soaked rubber dispersed on the water surface. The oil-free areas on the surface of water enabled the replenishment of oxygen in water. Consequently, there was a huge jump in the survival time of fish.

3.4 Dissolved Oxygen (DO) in Fresh and Marine Water Contaminated with Oil Fig.6. illustrates the variation of dissolved oxygen concentration with time in oil polluted fresh and marine water containing fish in the presence and absence of added recycled rubber particles. In both fresh and marine water in the presence of rubber particles, the DO concentration increased with time in a pattern similar to absorption of oil by recycled rubber particles. The higher DO level in the oil- polluted fresh water is consistent with the higher solubility of oxygen in fresh water than salt (marine) water. [22]

Figure 6. Variation of dissolved oxygen concentration with time for oil polluted fresh and marine water with fish In contrast, Fig. 6 also shows the difference in the decrease in DO concentration in both oil-polluted fresh and marine water containing fish in the absence of recycled rubber particles. In this case, it is obvious that the continuous film of oil on the water surface prevented the replenishment of DO consumed by organisms (fish) present in the water. Consequently, the DO concentration sharply decreased within the first 1hr 30min and further gradually decreased with increasing time. 3.5 Comparative Physical Properties of Fresh Crude Oil and Recovered Crude Mechanical press and solvent extraction were used to recover crude oil from oil-saturated rubber particles. Physical properties such as API gravity, pour point and distillation boiling range of the fresh crude (crude 1), crude oil recovered from rubber particles by mechanical press (crude 2) and solvent extraction (crude 3) were determined. These physical properties, API gravity, pour point and the parameters derived from API gravities and atmospheric distillation (UOP characterization factor, K, and molecular weight) are shown in table 1: Table 1: Physical properties of fresh crude oil and crude oil recovered from oil-soaked rubber particles.

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2nd International Conference On Engineering Research & Development: 1508 Innovations (15th – 17th April 2008), Benin City, Nigeria Physical Properties

API gravity (API degrees) Pour Point (oC) UOP Characterization factor, K Molecular Weight (g/g mol)

Fresh Crude (Crude 1)

Crude Oil recovered by mechanical expression (Crude 2)

Crude Oil recovered by solvent extraction (Crude 3)

30

32

30.5

-1

0

2

11.08

11.2

11.08

147

140

145

Given the multicomponent nature of crude oils, the differences in the measured properties between fresh crude oil and recovered crude oils are not significant (P  0.05) and are within experimental error. As expected, the values of the derived physical constants calculated from measured properties are also close and within acceptable values. For example, the K-value which is related to properties such as viscosity and critical temperature of petroleum and its fractions, falls within the values quoted for galf-coast crude (11.0 – 11.8) and Californian Crude (10.8 – 11.9) [23] 3.6 Use of Regenerated Recycled Rubber in Oil Absorption The regenerated rubber is one whose absorbed oil has been removed by solvent extraction and then dried. It was considered necessary to determine the loss of effectiveness of the recycled rubber after it had been previously used for absorption of oil.

Figure 7. Variation of absorption at 30oC (303K) with time for different regenerated rubber particle sizes Figure 7 shows the typical variation of crude oil absorption with regenerated rubber of various particle sizes at 30oC. The oil absorption pattern is similar to that of the fresh rubber. The difference lies in the levels of oil absorption which are lower when the regenerated recycled rubber is used. Figure 8 is a typical comparison of the equilibrium oil absorption for regenerated and fresh recycled rubbers for different particle sizes at temperatures of 15oC and 30oC.

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2nd International Conference On Engineering Research & Development: 1509 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 8. Comparison of equilibrium crude oil absorption for different rubber particle sizes (fresh and regenerated To quantify this relative reduction in oil absorption, the equilibrium oil absorption for the regenerated recycled rubber particles is expressed as a percent of the equilibrium oil absorption for the fresh recycled rubber particles. Thus for the 2.36mm size rubber particles the relative decrease in oil absorption at different temperatures ranged from 39 to 46% compared with 32 to 34% for the 0.3mm size rubber particles. This could be due to the efficiency of the oil recovery specifically and regeneration processes in general. It is easier for the solvent to penetrate the Table 2 – Summary results on the asphalt concrete mix using 0.2 rubbers to asphalt ratio for different rubber particle sizes Particle Size

Tensile strength (kPa* 103)

(mm)

Air cured

No Rubber

1.47

Water cured

Compressive modulus (kPa*107)

Tensile modulus (kPa*107)

Air cured Water cured

Air cured

9.02

10.84

Tensile Modulus ratio

Compressive Modulus ratio

Tensile Strength ratio

Water cured

shallower pores of the smaller particles than the deeper pores of the bigger particles. Incomplete removal of oil 0.212 1.78 the driving 1.64 10.14 process 12.85 0.95 0.93 will not only reduce force10.70 for the sorption but will 12.18 also result 0.95 in lower equilibrium absorption 0.425 The larger 1.87 difference 1.82in oil absorptions 11.06 0.99 0.99 0.98 levels. at11.03 the lower 13.28 temperature13.25 reflects the greater sensitivity of sorption 0.600 2.06 1.99 12.27 11.94 14.73 14.33 0.97 0.97 0.97 processes to reduction in driving force at lower temperatures. This is typical of regeneration processes [21]. 1.18 1.82 1.75 10.63 10.59 12.76 12.72 0.99 0.99 0.96 More stringent conditions are necessary to restore the surface close to its original state 2.36 1.70 1.51 10.14 9.26 12.18 11.11 0.91 0.91 0.89 1.24

7.47

8.97

0.83

0.83

0.83

4.0 Road Pavement Durability Improvement 4.1 Effect of rubber particle size on mechanical properties The variation in mechanical properties of mixes with the particle size of rubber is summarized in Table 2. As the particle size of rubber is increased from 0.2 mm to 0.60mm there was an initial increase in the tensile strength, tensile modulus and compressive modulus followed by a decrease in these properties as the rubber particle size was further increased from 0.60mm to 2.36mm. In other words, the best mechanical properties were achieved for a rubber particle size of 0.6mm. Satish and Yoshihiko[24] have made similar observations. They attribute the initial increase in mechanical properties to the filling of voids and bridging of micro-cracks by rubber particles of appropriate sizes. However, beyond a particular rubber particle size, compaction of aggregate becomes poor and thus weakening the bonds between aggregate and the binder (asphalt). This adversely affects mechanical properties. In case the reduction is between 17 and 25%. 4.2 Effect of water on Mechanical Properties The effect of water on the mechanical properties of both the rubberized and the conventional asphalt concrete is shown in Table 2. It is to be noted that for the rubberized asphalt concrete up to a rubber particle size

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2nd International Conference On Engineering Research & Development: 1510 Innovations (15th – 17th April 2008), Benin City, Nigeria of 1.18mm, there was no significant difference in mechanical properties of the specimens soaked in water and those left in open air. However, specimens without rubber show relatively lower mechanical properties. In particular, the moisture damage index for rubber-modified aggregates was essentially between 0.95 and 0.99 while that for the conventional specimens (rubber-free concrete) was 0.83. The tensile modulus ratio for the rubberized asphalt concrete mix is higher than 0.85, which according to Kennedy and Anagnos [25], is considered reasonable minimum value for specimens subjected to moisture conditioning. The inferior mechanical properties of conventional asphalt concrete as compared to the rubberized asphalt concrete may be attributed to possible ingress of water into the voids in the mix thus weakening the bond between the aggregate and the asphalt. These results agree with those of Kennedy and Anagnos [25] who reported that, well compacted mix should contain 4- 5% air void content in total mix and that more air voids allow large quantity of moisture to penetrate into the asphalt concrete mix and increase its stripping potential. For the rubberized asphalt-concrete mix, the possibility of stripping due to large air voids either does not exist or is reduced considerably, first because the voids are filled with rubber and secondly, the presence of rubber creates fairly hydrophobic mix. The results of this study demonstrate the overall superior performance of rubberized asphalt concrete mix over the conventional asphalt concrete mix. By extension, it is expected that pavements constructed with the more flexible rubber-modified aggregates will be more durable than those constructed from conventional aggregates. 4.3

Effect of rubber to asphalt ratio Figures 9–10 show the variation of tensile strength and elastic modulus of rubberized asphalt concrete with rubber/asphalt ratio for various rubber particle sizes. In all cases, an optimum in properties was shown at a rubber/asphalt ratio of 0.3. The results suggest that there is limited amount of voids in the aggregate microstructure. As rubber particles fill these voids, mechanical performance of the rubber asphalt concrete mix is enhanced. However, further increase in the amount of rubber particles leads to poor compaction and hence a degradation in mechanical properties of the mix. It is also possible that as the rubber particles increased the amount of the binder asphalt, which was kept constant in these samples, was inadequate to effectively bond the mix.

Figure 9. Variation of tensile strength with rubber/asphalt ratio for various rubber particle sizes.

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2nd International Conference On Engineering Research & Development: 1511 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 10. Variation of tensile modulus with rubber/asphalt ratio for various rubber particle sizes. 5. CONCLUSIONS: Recycled rubber from scrap tyres has been demonstrated to have potential for use in oil spill clean up because of its intrinsic ability to absorb oil. (i) At an absorption temperature of 30oC, the equilibrium oil absorption decreased from 4.98 to 1.80 g/g as the particle size of rubber increased from 0.15 to 2.36mm. (ii) As the temperature of the environment decreased from 30oC to 5oC, the equilibrium oil absorption increased from 4.21 to 5.49g/g for 0.6mm rubber particle size. (iii) The pattern and capacity of recycled rubber particles to absorb crude oil were not determined or influenced by the surface (fresh water or marine water) on which the oil spillage occurred. This has positive implications for the use of rubber for oil pollution control in open seas, rivers and creeks. (iv)

Regenerated recycled rubber is less efficient than fresh recycled rubber in potential oil-clean up operations.

(v)

The physical properties of recovered crude oil are similar to those of fresh crude oil. Consequently, the recovered crude oil can be refined for the manufacture of the usual petroleum products.

In addition, the elastic, resilient and hydrophobic nature of rubber from recycled scrap tyres can permit its use in enhancing the durability of road pavements. (i)

As the particle size of rubber was increased from 0.2mm to 0.60mm there was an initial increase in the mechanical properties of rubber-modified asphalt concrete. This was followed by a decrease in properties as the size of rubber was increased further to 2.36mm.

(ii)

For various rubber particle sizes, the tensile strength and elastic modulus of rubber-modified asphalt aggregate increased and then decreased with increasing rubber/asphalt ratio with optimum properties shown at a rubber/ asphalt ratio of 0.3.

(iii)

Water has no significant effect on the mechanical properties of rubberized asphalt concrete. In contrast, conventional (rubber-free) asphalt concretes were degraded below acceptable limits after soaking in water for 28 days.

6.

REFERENCES

1. R.O. Ebewele and L.H Dzong: “Potential application of recycled rubber”. Nigerian J Engineering 6(1) 1-3; (1990). 2. M. Ewadinger and R.Steuteville “New generation of tyre processing” Bicycle 37(1), P40, 2p, 2bw (1996). 3. Martin, Amy; “Tyre recycling in America” Garbage 3(3), P28, 7 (1991). pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1512 Innovations (15th – 17th April 2008), Benin City, Nigeria 4. World Bank; “Nigeria: Strategic options for redressing industrial pollution”, Vol 2 (1995). 5. A, Nelson – Smith: “Effect of oil spills on land and water: effects of cleaning up the oil”. In J Wardley – Smith (ed). The prevention of oil pollution. Graham and Trotman Ltd, London pp 17 – 34 (1979). 6. C.N. Ifeadi and J.N. Nwankwo “A critical analysis of oil spill incidents in Nigerian Petroleum Industry” in Proceedings of International Seminar on the Petroleum Industry and the Nigerian Environment. N.N.P.C and F.M.W.H. Lagos pp 104 -111 (1987). 7. C.K. Lewicke: “Cleaning up of oil spills isn’t simple”. Environ Sci Tech 7 (39), 400 (1973) 8. A.M.A.E. Imevbore and J.A Ekundayo “Effect of crude oil effluent discharge on the water quality and biological production in the Niger – Delta Nigeria” Final Report, Shell Petroleum Development Company, Nig Ltd Lagos pp 197 – 260 (1987) 9.

A.I. Prudnikov and V.I. Smtanjuk “Polymer absorbent for production of aqueous media contaminated by petroleum and petroleum product” PCT Int Appl. No 9417, 909, 19pp (1994).

10. L. Bateman “The Chemistry and Physics of rubber – like substance” Bateman L. (ed), Maclaran London pp 449 (1964) 11. N. Robert Doty “Flexible Pavement Rehabilitation using asphalt – rubber combinations: a progress record in: Transportation Research Record 1196, TRB, National Research Council, Washington, D.C. 213 -223 (1988) 12.

S.K. De “Reusue of ground rubber waste: a review”. Rubber Technology Center, Indian Institute of Technology, Kharagpur, India (1999).

13. M.B. Takallou and A. Sainton “Advances in technology of asphalt paving materials containing used tyre rubber” Transportation Research Record 1339, TRB (1992) 14.

J. Emery, “Evaluation of rubber-modified asphalt demonstration projects,” Canadian Technical Asphalt Association Proceedings Regina; 337 – 361 (1994).

15.

D. Brehem and M.J. Lucus: “Evaluation of rubber –modified asphalt concrete” PADOT Research Project NO 90 -063. Pennsylvania Dept of Transportation (1998).

16. D. Jared: “Evaluation of crumb rubber in hot- mix asphalt” GDOT Research Project NO 9107, Office of Materials and Research Georgia, Georgia Department of Transportation, Georgia, (1997). 17. F.A. Aisien, F.K. Hymore and R.O. Ebewele “Potential application of rubber in oil pollution control”. Environment Monitoring and Assessment 85, 175 -190 (2003) 18. F.A. Aisien, F.K. Hymore and R.O. Ebewele: “ Application of ground scrap tyre rubbers in asphalt concrete pavements” Indian Journal of Engineering and Materials Sciences; 3 (8) 333 – 338 (2006). 19. F.A. Aisien, F.K. Hymore and R.O. Ebewele, “Comparative absorption of crude oil from fresh and marine water using recycled rubber” Journal of Environmental Engineering, 132 (9), 1078 – 1081 (2006).

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2nd International Conference On Engineering Research & Development: 1513 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08100) DESIGN AND IMPLEMENTATION OF A GSM ACTIVATED AUTOMOBILE DEMOBILIZER WTH IDENTIFICATION CAPABILITY

M. S. OKUNDAMIYA (1), J. O. EMAGBETERE

(2)

, F. O. EDEKO (3)

(1)

Department of Electrical/Electronic Engineering, Ambrose Alli University, Ekpoma. +2348066263858; [email protected] (2, 3) Department of Electrical/Electronic Engineering, University of Benin, Benin City. [email protected]

Abstract: The incidence of car theft in Nigeria is on the alarming increase. On daily basis, the numbers of stolen cars reported over the media are on the increase. Alarms and other deterrents are not enough. There is actually little one can do to prevent a car from being stolen. However, with a Global System of Mobile communication (GSM) activated automobile demobilizer with identification capability one can virtually take control of the virtually impossible incidence and hence increase the possibility of car recovery. This paper is aimed at implementing a security device capable of safeguarding cars from theft as well as provides picture and audio information of the culprits in an attempt to steal the car. To realize this work, use was made of a GSM owners phone that has a Multimedia Messaging Service (MMS) capability, a Signaling Processing Unit built around electronic components and a GSM camera phone positioned at an angle in the car. The dialing network processes and the MMS to the owner’s phone. This process takes about six (6) minutes before the ignition coil is disconnected from the battery of the car. 1. Introduction The security of cars in Nigeria has deteriorated over the past years, with a growing need to combat car theft. These crimes tend to its peak between November and January, most often during the holiday periods. To put this obnoxious trend to an end, the need of designing and implementing a security device with wide range of flexibility in control timing, capable of providing and storing the audio and picture image of the culprits (intruders) for identification and prosecution evolved, thus providing a lasting solution to car theft worldwide.[1] The device can be controlled with a GSM handset, and can conveniently deactivate the car from a distant (remote) location providing the owner the audio and picture information of the culprits for possible prosecution and recovery of the car incase it was stolen at gunpoint or from where it was packed. 2. Literature Review Prior to the development of digital electronics, car engine demobilizer use analogue timers with a preset reset, which works until the preset time is reach. With the advent of digital electronics, counter like NE555 timers, JKFlip flop, binary and decade counters [2] reached. With the development of digital electronics, digital counters like NE555 timers [1]. were employed being superior to their analogue counterpart in terms of noise, and are relatively small in size making it difficult to be detected in the car system. In this work, we used a GSM handset as a control unit to deactivate the security device as well as provide and stores the picture image and information of the culprits should in case the car was stolen.

3. Methodology/Design Consideration The design and implementation of the GSM activated automobile demobilizer with identification capability is achieved using both discrete components and integrated circuits (ICs). The entire circuitry is designed around a Sony Ericsson K600i Camera Phone that is MMS compatible. It consists of three parts: Power Supply Unit, Signal Processing Unit, and the Latch Shutdown Circuitry 4. Design Analysis The design analysis is carried out in stages. Figure 1 shows the charging circuit

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2nd International Conference On Engineering Research & Development: 1514 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 1: The charging circuit The charging resistance, Rcharge is given as; [3]

R ch arg e  R1 

V1  VF …………………………………………………………. I ch arg e

(4)

and

I ch arg e  0.1I max

……………………………………………………………

(5)

I max is the current capacity of rechargeable battery, VF is the forward voltage drop of diode D1 and V1 is the voltage of car battery. The power dissipated, PRch arg e by the choke resistor is

PRch arg e  I 2 Rch arg e )URP&DU %DWWHU\

…………………………………………………………

'

/07 )URP5HFKDUJHDEOH %DWWHU\

'

9





(6)

5



5

&

 

Figure 2: Schematics a Constant 3.9 volts Supply using LM317T The parameters can be calculated as; [4]

V  R2  R3  out  1 V   ref 

………………………………………………

(7)

Vref is 1.25 volts while standard values of R1 range from 220 ¿ - 240 ¿. Vout is designed to be 3.9 volts. The oscillatory frequency, fosc of CMOS Relaxation RC Oscillator Circuit is designed as

f osc 

1 R4 C 2

…………………………………………………………….

(8)

The timing resistor R4 and capacitor C2 are chosen The induced voltage across the inductor of the forward DC-DC converter is given as; [5, 6] ………………………………………………………… (9) V L  LI L f L is the inductance of coil, f is the oscillatory frequency and IL is the induced Current. The cut-off frequency, fc of the low-pass filter formed by the C3 and D4 is given as; [7]

1 ………………………………………………………… 2R f C3 Rf is the specified forward resistance of D4 (=400  ) fC 

(10)

The input current IB3 of the Darlington Transistor is designed such that ;[3] pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1515 Innovations (15th – 17th April 2008), Benin City, Nigeria I E4 h fe 4  1h fe3  1

I B3 

.....................................................................................(11)

KTC9014 current gain, hfe3 is 200 (given) and D882 current gain, hfe4 is 12 and IE4 is the required charging current, designed to be 500mA; [3]

RE 3 

VZ

 V BE 3  I B3

..............................................................................................

(12)

The bit number, N of binary counters is given as; [8]

N  2n

............................................................................................... (13) Where n is the number of stage and it is specified to be 14 for CD4020. The input period of the interrupt charger is; [8]

Tin 

Tout 214

……………………………………………………………..

Tout is chosen to be 3600 seconds. For RC DC circuits the timing constant is given as; [3] T  RC ............................................................................................ And

R8 

Tin C5

…………………………………………………………

(14)

(15)

(16)

C5 is chosen.

Figure 3: Common Collector Fixed Base Bias Buffered with an Emitter Follower.[7] From Figure 3, the emitter follower is biased such that

1 VE 7  VCC 2 V V RE 7  E 7  CC I E 7 2I E 7 I E 7  IC 7  I B7

I E 7  I B 7 h fe 7  1 I B7 

IE7 h fe7  1

………………………………………………………………

(17)

………………………………………………………………

(18)

..............................................................................................

(19)

..............................................................................................

(20)

................................................................................................

(21)

.............................................................................................

(22)

VCE 6  VE 7  VBE 7 VBB 6  VCE 6  VBE 6 V  VCE 6  RC 6  CC IC 6

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2nd International Conference On Engineering Research & Development: 1516 Innovations (15th – 17th April 2008), Benin City, Nigeria I B6 

IC 6 h fe 6

..............................................................................................

RB 6 

VBB 6 I B6

................................................................................................... (24)

(23)

C6 = C7 = 0.01F(chosen) The gain, G of the amplifier in figure 4 is given by Ebers-Moll Equation as; [7]

G

RL RE

…………………………………………………………

(25)

Where RL is the load resistance (=RC6) and RE is the total emitter resistance R E  Re  re …………………………………………………………

(26)

Where Re is the external resistance and re is the internal intrinsic resistance. Thus

G

RL RE  re 

………………………………………………..

(27)

Since emitter for T6 is grounded, Re = 0 thus Equation (27) becomes

RC 6 re V G  out Vin Vout  GVin G

……………………………………………………..

(28)

………………………………………………..

(29)

………………………………………………………. (30)

Figure 4: Transistor Schmitt Trigger.[9] From Figure 4, the design of the input (turn-on) voltage is such that Vin  0.6V ……………………………………………………..

1 VE 8  VCC ……………………………………………… 4 1 VCE 8  VCC ……………………………………………… 2 V  VCE 8  V ......................................................... ......... RC 8  C 8  CC IC8 IC8 I E 8  I C 8  I B8

(31) (32) (33) (34)

since Ic >> IB

I E8  IC8

.................................................................................

(35)

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2nd International Conference On Engineering Research & Development: 1517 Innovations (15th – 17th April 2008), Benin City, Nigeria RE 8 

VE 8 I E8

Similarly for T9

RC 9 

VCC  VCE 9  IC 9

I E 9  IC 9

................................................................................... (36) ..................................................................................

(37)

The output period of two cascaded decade counters is given as; [8]

Tout  100Tin

…………………………………………………………

(38)

Figure 5: Latch Circuit used to drive a Transistor Relay Driver. The trigger (ON) voltage is; [2]

1 Vth  Vcc 3

………………………………………………………………… (39)

R21 = R25 = 10KÙ (chosen) R 24  1K (chosen)

The relay effective resistance is given as; [3]

Reff 

Rrly Rrly Rrly  Rrly



Rrly 2

…………….. (40)

Using h parameters [5]

IB 

IC h fe

………………………………………………………………. (41)

C10 = C11 = C12 = C13 = C14 = C15 = 0.01ìF (chosen) 5. Operational Principles of the GSM Activated Automobile Demobilizer with Identification Capability The power supply unit, which consists of the charging circuit, the conditioned voltage supply and the one hour interrupt GSM charger is designed to charge the GSM phone battery as well as the rechargeable (backup) battery, which supplies the entire system in case the car battery is disconnected. The diode OR-Gate is designed such that the car battery having a higher potential of 12 volts, supplies current to the LM317T voltage regulator which in turn supplies a constant 3.9 volts to the whole system. The clock oscillation section is designed around the MM74HC14 Hex Inverting Schmitt Trigger and it runs from the 3.9 volts. The MM74HC14 Hex Inverting Schmitt Trigger sends clock signals to CD4020 and CD4017. When the Sony Ericsson K600i camera phone positioned within the signal processing unit receives the audio signal (ring tone) from the caller’s phone through the earpiece, this signal is connected to the input of the common collector fixed base bias small signal amplifier with emitter follower. This amplifier amplifies the incoming signal and its output is sent to the transistor Schmitt Trigger, which converts the sine wave (audio signal) into a square wave. The output of the square wave is used to clock the first decade counter; CD4017 whose odd outputs via IN4001 signal diodes is connected to an LED. The LED flashes as the sine wave signal flow through it. The outputs of this counter through IN4001 are used to trigger the master latch circuit. This is shown in figure 6. The master latch circuit designed around an NE555 timer and two KTC 9014 Transistors, pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1518 Innovations (15th – 17th April 2008), Benin City, Nigeria activates a transistor relay driver circuit. This relay when activated supplies +6 volts to the dialing network. The dialing network consists of cascaded Johnson Counters: CD4017 (2) and CD4017 (3), a Schmitt Trigger RC Oscillator, a transistor relay switch, two transistors relay circuits driven by monostable circuits and the Sony Ericsson K600i Camera Phone. The cascaded counter is fed by the Schmitt Trigger RC Oscillator, which generates 1.2 seconds clocked signal. From the time the dialing network was activated, the cascaded counter initializes its counting sequence and after 24 seconds, output “1” of CD4017 (2) through IN4001 and a transistor relay switch activates the snap button on the GSM phone keypad while output “2” and output “3” via IN4001 signal diodes feed a transistor relay switch driven by a monostable circuit. This helps to process the picture information of the intruder and send same to the owner’s phone whose SIM number has previously been stored in the demobilizer’s contact. The owner’s phone must be MMS compatible and must be activated by the GSM service provider to enable access. Output “4” of CD4017 acts as a delay, while output “5” is used to activate another monostable circuit. This circuit drives a transistor relay switch which in turn is used to clear the screen of the K600i Camera Phone. Output “6” also acts as a delay while at 94 seconds, output “7” is used to dial the caller so that when he or she accepts the call is able to listen to the audio conversation of the occupants in the car as well as what is going on in the surrounding environment in order to determine the location of the car and be equipped with vital information. Output “8” also acts as a delay while at 120 seconds, output “9” is used to enable CD4017 (3). Output “1” of this counter at 360 seconds from the initial counting sequence (start time) through IN4001 activates the shutdown latch circuit. This in turn forward biases transistor, T10 (KTC9014). With T10 turning ON I C10 flows thus reverse biasing T11 . This turns OFF the relay connected to the ignition coil thereby switching OFF the car. This action is indicated by the switching OFF of the LED connected between the relay terminal and ground. At the same time the output signal from output “1” of CD4017 (3) is used to reset the master latch circuit thereby switching OFF power supply from the dialing network. After the car has been demobilized, the caller still has access to the audio information within the car for as long as the demobilizer’s SIM is recharged. The entire circuit can be reset first by pressing the hidden reset button to reset the shutdown latch circuit and then switching OFF and then ON the power supply switch. This helps to deactivate the CD4017 (1). However when the power supply is switched ON, the CD4017 (1) can not be activated without the external 900MHz GSM signal. This is because the two 0.01F capacitors C6 and C7 help to block the DC voltage between the GSM phone and the Transistor Schmitt Trigger thus keeping it OFF. 6. Results The test results are shown in table 2 below. Table 1: Test Results S/N

Parameters

Theoretical Values

Designed Values

Measured Values

1.

7.

Charging Current , 450mA 380mA 350mA Icharge 2. Charging Voltage , 12V 11.6V 11.6V Vcharge 3. Output Voltage to Adjustable 3.9V 3.9V LM317T, Vout 4. Input Voltage to 12V 11.7V 11.7V LM317T, Vin 5. Output frequency 20KHz 20KHz from Schmitt Trigger 0 – 16MHz (adjustable) (adjustable) Oscillator 6. Minimum Current to 300mA 400mA 350mA charge phone 7. Maximum Current to 550mA 500mA 480mA charge phone 8. Minimum Voltage to 4.2V 5V 5V charge phone Conclusion. 9. Maximum Voltage to 6V 6V 6V charge phone 10. Forward biased -VBE 0.6V – 0.7Vthat0.6V pdfMachine is a pdf writer produces 0.65V quality PDF files with ease! of Audio Pre-Amp Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot 11. Base voltage of easier to use and much preferable to Adobe's" A.Sarras - USA

KTC9014

2.55V

1.95V

2.45V

2nd International Conference On Engineering Research & Development: 1519 Innovations (15th – 17th April 2008), Benin City, Nigeria In this paper, we have been able to design and implement a GSM activated automobile demobilizer with identification capability, which provides a mechanism that can conveniently secure automobile cars from theft, and in case of theft can transmit the audio signal and picture image of the occupants of the car to the owners phone and shutdown the car in 2 minutes to enable the owner recover it. The owner can identify and if possible arrests the culprits through the stored information (photographs and audio conversations) in the GSM handset. References. [1] http://www.premium-mobile.com/content/2-billion-gsm-users-worldwide/ [2] M. B. Harvard, “Learn how to Connect the 555 Timer, perform 17 Experiments”, Cambridge University Press, 1995. [3] A.K. Theraja and B. L. Theraja, “A Textbook of Electrical Technology”, 22nd Edition, S. Chand and Co., New Delhi, 1995. [4] P. Horowitz, and W. Hill, “The Art of Electronics”, Cambridge University Press, Low Price Edition, 2002. [5] P. Rudy and G. Severns, “Modern DC-DC Switchmode Power Conversion Circuits”, Van Nostrand Reinhold, 1985. [6] S. K. Andre, R. Richard and O. S. Nathan, “Dynamic Analysis of Switch-Mode DC-DC Converters”, Van Nostrand Reinhold, 1991. [7] V. O Akpaida, O.Omorogiuwa and M. S. Okundamiya, “Principles of Electronic Devices and Circuits”, Stemic Publications, Benin City, 2005. [8] J. R. Nowicki and L. J. Adams, “Digital Circuits”,Prentice-Hall International, 1993. [9] F. Sergio, “Design with Operational Amplifier and Analog Integrated Circuits”, McGraw Hill Series, International Edition, 1988. [10] P. C. Juan, “The Greatest Communication Inventions”, IET Communications Engineer, Vol. 5, Issue 1, UK, (March 2007) 19. [11] L. Yim-Shu, “Computer-Aided Analysis and Design of Switch-Mode Power Supplies”, Marcel Dekker, 1993. [12] C. C. George, “High Frequency Switching Power Supplies: Theory and Designs”,McGraw-Hill, New York, 1989. [13] C. E. Strangio, “Digital Electronic Fundamental Concept and Application”, McGraw Hill, 1983. A. K. Yusufu, “Cellular Wireless Communications: Evolution and Impact Assessment”, Journal of Engineering Science and Application (JESA), Vol. 3, No. 2, Ekpoma, (Dec. 2002). 31 [14] W. E. Robert and M. Dragan, “Fundamentals of Power Electronics”, Kluwer Academic Publishers, 2001

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2nd International Conference On Engineering Research & Development: 1520 Innovations (15th – 17th April 2008), Benin City, Nigeria

Figure 6: Complete Circuit Diagram of GSM Activated Automobile Demobilizer with Identification Capability

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2nd International Conference On Engineering Research & Development: 1521 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08273) INVESTIGATION OF THE CHARACTERISTIC OF INDOOR RADIO PROPAGATION

J.O EMAGBETERE and F.O. EDEKO Department of Electrical/Electronic Engineering University of Benin, Benin-City. Email: [email protected] Abstract The success of wireless local area networks (WLANs) has led to an intense interest among wireless engineers in understanding and predicting radio propagation characteristics within buildings. This paper present’s radio signal propagation measurement and modeling at 2.4GHz, within a building in the Faculty of Engineering, University of Benin. A base station built around SENAO access point, and a PA24 flat panel directional antenna of 19dBi gain and 17.50 beam-widths was setup for the experimentation. Signals were monitored using LINKSYS and NET STUMBLER version 4.0 software run on a Laptop, from the PA24 flat panel antenna. In this report, the effect of multi-path and delay spread is not considered. The result of the investigation reveals that the walls of the buildings attenuate the radio signal significantly with distance with a path loss exponent of 7.8 to 8.9 on the ground floor, and 2.9 to 5.2 for the 2nd floor. Keywords: Radio propagation, Indoor environment, Personal Communication System, Propagation Characteristic. 1 Introduction The use of wireless local area networks (WLANs) is rapidly growing in popularity. These networks use the unlicensed bands at 2.4 – 2.5GHz or at 5.15 – 5.85GHz. The networks are primarily targeted for indoor use. With the advent of Personal Communication Systems (PCS), there is a great deal of interest in characterizing radio propagation inside buildings. [1-4]. The design of Wireless local area networks requires that a high standard of radio coverage in indoor environment is important. To achieve this standard, an accurate propagation model is necessary to give a radio coverage prediction which can be employed to make planning and installation of these systems more effective.[2, 5-8]. Until now, researches on the signal behavior in buildings are not common in our country, although numerous experimental and theoretical studies of indoor propagation have been performed in the developed countries. And weak reception or failure in services provided by these wireless local area networks is often attributed to the system congestion as a result of limited bandwidth. The purpose of this investigation is to examine the behavior of the signal strength received from a transmitting antenna, and to develop an empirical formulation to predict radio signal power level and the radio attenuation with distance. 2 Theory of Indoor radio propagation Radio waves are propagated through space at the speed of light. However, this speed is only attained assuming there were no obstructions for the electromagnetic wave to pass through. Hence the wave speed varies as the electromagnetic wave pass through different substances. And as the signal propagates, factors such as penetration, reflection, absorption e.t.c affects the signal, hence it decreases with distance. The

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2nd International Conference On Engineering Research & Development: 1522 Innovations (15th – 17th April 2008), Benin City, Nigeria propagation mechanism not only affects the signal amplitude, but also the signal direction.[6] Propagation within buildings is strongly influenced by specific features such as the layout of the building, the construction materials and the building types, as such the signal levels vary greatly. Radio propagation in indoor environment is complex. The indoor radio channel coverage area is small, and the variability of the environment is much greater for a much smaller range of transmitter-receiver separation distances. [7,8]. The height of the transmitting antenna also affects the signal level, hence an antenna mounted at desk level in a partitioned office receive vastly different signals than those mounted on the ceiling. Buildings have a wide variety of partitions and obstacles which form the internal and external structure. Radio frequency (RF) propagation obstacles can be term hard partitions if they are part of the physical/structural components of a building, or soft partition if the obstacles formed by the office furniture and fixed or movable/portable structures that do not extend to a building ceiling. [7,8,9]. Since we can not do anything about the buildings, building materials or structures, the need to explore the overall signal propagation in a building, in order to predict the signal levels and range of the signal losses presented in a building is important. [7-9] To enable this prediction, a number of measurements is required from which the signal propagation characteristic in building is analyzed. 3 Experimental method The block used for this investigation is a two-storey building. Only the ground floor and the 2nd floor of this building were considered for this investigation. We monitored signal strength from a vertically-oriented PA24 model antenna with a Laptop programmed to the software (NetStumbler and Linksys) mode, on different floors. With the aid of a meter tape, we marked different sampling points from the antenna at 10 meters interval until the signal fade. At each sampling point (norminal location), twenty (20) samples of signal strength readings in dBm, were taken with the Linksys and the NetStumbler softwares independently with the same Laptop. This ensures uniformity of the measuring equipment with the different softwares. Readings of the Signal-to-Noise ratio (SNR) and the Noise level in dB were recorded using the NetStumbler software. With the SNR and Noise level measured, the received signal power obtained were computed for the NetStumbler as in equation (1) [10], and the result tabulated as shown in Table 1 and 2 for the ground and 2nd floor respectively. In Tables 1 and 2, the signal power measured with the Linksys software is also tabulated. Signal Strength (dBm) = SNR + Noise …………………………………….. (1) ……………………………………...(2) Pr  P0  10n log( d / d 0 ) Where, d0 is the reference distance from the transmitting antenna, d is the transmit-receive separation distance, P0 is the received signal power at reference distance, Pr is the mean power received. The value of d0 measured was 2.5m from the transmit antenna. 4

Data Presentation

The received signal strength recorded at different point from the antenna using both software are as shown in Table 1 for the ground floor. And for the 2nd floor, the following values of signal strength recorded against distance are shown in Table 2. Table 1: Signal strength at ground floor

Table 2: Signal strength at 2nd floor

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2nd International Conference On Engineering Research & Development: 1523 Innovations (15th – 17th April 2008), Benin City, Nigeria

Sample points 10m 20m 30m 40m 50m

Netstumbler Net Signal Linksys Stumbler to Noise Software Software ratio (dBm) (dBm) (dBm) -22.5 -20.1 79.9 -33.8 -34.4 65.6 -62.1 -63.2 36.8 -65.8 -67.0 33.0 nil -81.0 19.0

Netstumbler Signal Net Linksys Stumbler to Noise Software Software ratio (dBm) (dBm) (dBm) -22.0 -40.6 57.4 -39.2 -24.3 75.7 -18.2 -28.4 71.6 -31.6 -37.7 62.3 -50.3 -33.0 67.1 -46.5 -47.5 53.0 -44.3 -43.5 56.5 -54.6 -42.0 54.2 -73.9 -50.9 49.1 -80.5 -71.0 29.0 -70.0 -63.5 36.5

Sample points 10m 20m 30m 40m 50m 60m 70m 80m 90m 100m 110m

5 Results and discussion In order to easily assess the behavior of signal propagation in the indoor environment, we plotted bar charts of the received signal strength (dBm) as a function of transmit-receive separation distance. For the ground and the 2nd floor, the signal behavior in terms of the received signal strength is shown in Figure 1 and 2 respectively. 2nd Floor

Ground Floor

S i g n a l S tr e n g t h ( d B m ) T H T

80 70 60 50

Linksys NetStumbler

40 30 20

S ig n a l s tr e n g th (d B m ) T H T

90

90

80 70 60 50

Linksys

40

NetStumbler

30 20 10

10

0

0 1

2

3

4

5

Sample point

Figure 1: Bar chart of signal strength for different software on ground floor

1

2

3

4

5

6

7

8

9

10

11

Sample points

Figure 2: Bar chart of signal strength for different software on the 2nd floor

We also compare the received signal response using the NetStumbler with its SNR as shown in the line graph in Figure 3 and 4, for the ground and 2nd floor respectively. Figure 3 and 4 shown demonstrate the relationship between the received signal strength and the signal-tonoise ratio.

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2nd International Conference On Engineering Research & Development: 1524 Innovations (15th – 17th April 2008), Benin City, Nigeria 2nd Floor

90

80

80

70

S ig n a l P a ra m ete r T H

S ignal P aram eter TH

Ground Floor

70 60 50

Signal Strength (dBm)

40

Signal-to-Noise ratio (dB)

30 20 10 0 1

2

3

4

60 50 Signal-to-Noise ratio (dB)

40

Signal Strength (dBm)

30 20 10

5

0

Sample points

1

2

3

4

5

6

7

8

9

10

11

Sample points

Figure 3: The NetStumbler response in terms SNR and received signal power with distance for the ground floor

Figure4: The NetStumbler response in terms SNR and received signal power with for the 2nd floor

Ground Floor

2nd Floor -10

Signal strength with NetStumbler Signal Strengthwith Linksys

-20

Measured data with Linksys Signal Strength with Linksys Measured data with NetStumbler Signal Strength with NetStumbler

-20 -30

Power received (dBm)

Power received (dBm)

-30 -40

-50

-60

-40

-50

-60

-70

-70 -80 0.6

-80 0.7

0.8

0.9 1 Log of Distance (m)

1.1

1.2

1.3

Figure 5: Plot of received signal power with distance power for the ground floor

0.6

0.7

0.8

0.9

1 1.1 1.2 1.3 Log of Distance (m)

1.4

1.5

1.6

Figure 6: Plot of received signal with distance for the 2nd floor

Figure 5 and 6 is a graphical representation of the linear regression model based on the result obtained from measurement. The propagation model developed based on measured data, using equation 2, with the Linksys software for the ground floor at d 0  2.5m , is Pr  78 log D  58 . This model account for about 90% of the actual measurement of power received about the mean value, with a root mean square error of 7.815, and a normal standard deviation of 21.23dBm for a transmit-received separation distance of 50m. The path loss exponent n  7.8 . The propagation model developed based on measurement with the NetStumbler in the

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2nd International Conference On Engineering Research & Development: 1525 Innovations (15th – 17th April 2008), Benin City, Nigeria same floor is Pr  89 log D  37 , with a propagation exponent of 8.9, normal standard deviation of 25.06dBm, and a root mean square error of 6.429, from a linear fit accounting for about 95% of the actual measurement of power received about the mean value. With the Linksys software, at d 0  2.5m , The mean power received model for the 2nd Floor is Pr  52 log D  19 . Statistically, a normal standard deviation of 20.46dBm, and a root mean square error of 12.23 was observed. And with the NetStumbler at d 0  2.5m , The mean power received model for the 2nd Floor is Pr  29 log D  6 . Statistically, a normal standard deviation of 14.06dBm, and a root mean square error of 10.96 was observed. 6 Conclusion This paper presented the result of radio propagation characteristics in terms of the path loss exponent, and the normal standard deviation of the received signal strength for single floors of a two-storey building. The values of the propagation path loss exponent obtained are for the same floor measurement, with the high exponent of 7.8 to 8.9 observed for the ground floor as compare to 2.9 to 5.2 for the 2nd floor. The high standard deviation of about 21.23dBm to 25.06dBm for the ground floor, and 10.96dBm to 12.23dBm for the 2nd floor reveal the need for proper planning of the radio coverage to avoid a tight fade margin which will eventually leads to frequent downtime in stations on the network. The high path loss exponent from the ground floor is the result of the concrete walls, pillars and other hard partition structures used in its construction. The propagation models developed may aid in site planning and deployment of indoor-to-indoor wireless local area networks. 7

REFERENCES 1. Wheat J, Hiser R., Tucker J., Neely A., McCullough A., (2001), ‘Designing a Wireless Network’, Syngress Publising, Pp 73-80, 133-135. 2. Rackley S., (2007), ‘Wireless Networking Technology’, Newnes Publishing, Pp 10, 40-45, 98-102 3. Olexa R., ‘(2005), ‘Implementing 802.11, 802.16, 802.20 Wireless Networks Planning, Troubleshooting and Operations’, Newnes Publishing, Pp 7-9 4. Dan D., (October 2002), ‘Indoor Propagation and Wavelength, WJ Communications, Vol 1. 4. 5. G. Durgin, T.S. Rappaport, and H. Xu, ‘Measurements and Models for Radio Path Loss and Penetration Loss in and around homes and trees at 5.85 GHz, IEEE transactions on communications, Vol. 46, No 11, November 1998. 6. J.H. Tarng, Effective models in evaluating radio coverage on single floors of multifloor buildings, IEEE transactions on vehicular technology, vol. 48, No. 3, May 1999. 7. Rappaport T.S., and Sandhu S., (October 1994), ‘Radio-Wave Propagation for Emerging Wireless Personal-Communication Systems’, IEEE Antennas and Propagation Magazine, Vol 36. No 5. 8. T.S. Rappaport, ‘Wireless communications principles and practice’, Prentice Hall of India, New Delhi-110001, second edition, 2003. 9. http:/www.sss-mag.com/indoor.html, Indoor Radio Propagation, by SSS online and Pegasus Tech, June 2001. 10. M.F. Young, Planning a Microwave link, www.ydi.com

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2nd International Conference On Engineering Research & Development: 1526 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08074) MAJOR FEEDER PILLAR FAULTS IDENTIFICATION USING PARETO ANALYSIS E.A Ogujor (1), E.U Ubeku (2), P.T Aikhoje (3) Department of Electrical/Electronic Engineering, University of Benin, Benin City. Nigeria. Phone: +2348056058740 e-mail: [email protected] (1,2,3)

Abstract Application of Pareto Analysis technique in major feeder pillar faults identification is presented in this paper. Power outage data due to feeder pillar faults were collected between January, 2005 and September, 2007 from Power Holding Company of Nigeria (PHCN), Ugbowo district office, Edo State, Nigeria for four feeder pillars. The data were processed and Pareto Analysis technique was applied to the field data. The results obtained shows that eliminating wrong fusing and overloading in Edaiken 2 and Holex feeder pillars will reduce faults by 77.42 and 79.53% respectively while eliminating wrong fusing, overloading and line-to-line faults in Uwasota 2 and Holy Rosary feeder pillars will reduce faults by 87.9 and 88.35% respectively.

1. INTRODUCTION The generation, transmission and distribution of electrical energy are aimed at providing electric power. The closest part of the electricity network to consumers is the distribution network. It is a collection of equipment put together to ensure that power is effectively, reliably and securely delivered from generation through transmission stations to the consumers. The Nigeria distribution system as a developing one with horizontally distributed customers is characterised by very long radial circuits, under sized distribution conductors and high concentration of factors that impact reliability [1] In Nigeria, between the primary distributions voltage of 11kV to the secondary distribution voltage of 0.415kV lies various equipment such as transformer, cable and feeder pillars etc. A typical distribution network is shown in Fig. 1. TX 1– TRANSFORMER 33kV/11kV TX 2 - TRANSFORMER 11kV/0.415kV FP – FEEDER PILLAR - THREE PHASE -THREE & NEUTRAL

TX 1

TX 2

FP

Figure 1 A typical distribution network

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2nd International Conference On Engineering Research & Development: 1527 Innovations (15th – 17th April 2008), Benin City, Nigeria Transformers and cables have very high efficiency. Thus this research is based on the feeder pillar. A feeder pillar is box-like outdoor electrical equipment used for the distribution of electricity at low voltage (0.380kV-0.415kV). It is connected to the transformer by cables of about 1.8- 3 metre in length; it receives electric power at 0.415kV. The feeder pillar distributes the power in units to the consumer and protects the bigger system from faults that occur in the secondary distribution end. A picture of a feeder pillar is shown in Fig.2.

Figure 2 A diagram of a feeder pillar. The load demanded is used as parameter of design of the feeder to be installed. This is calculated from the total load connected to the transformer. The fuse is the protective/isolating component in the feeder pillar; in situations of current surge or overload it isolates the consumers from the supply thereby protecting the transformer. The feeder pillar consists of the following components: (a) cubicle/chassis (b) insulators (c) bus bars (d) current transformers (e) incoming units (f) outgoing units (g) fuses The fuse is an electrical protective devices, essentially a short piece of wire or conductor appropriately rated, which melts when excess current flows through it thereby breaking the circuits continuity. The fuse wire detects fault current by melting and isolates the faulty part/overloaded part of the circuit. The sensitivity of a fuse is how fast it breaks the circuit in an event of current surge.

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2nd International Conference On Engineering Research & Development: 1528 Innovations (15th – 17th April 2008), Benin City, Nigeria Fuse wire design Fuse wire elements are normally enclosed in ceramic (porcelain) hollow cylinder, connected to metallic caps at both ends. The fuse wire terminated at both ends to the metallic caps; sometimes the metallic caps have fuse holders which make necessary firm contacts to the clicks. The space inside the cylinder is usually filled with very fine silica sand. All the elements are properly designed and rated for various types of circuits in which they may be used. Figure 3 A diagram of a fuse The maximum current the fusing element can safely carry without undue heating or melting is called the rated current carrying capacity of the fuse. This value depends on the permissible temperature of the fuse holder while the minimum current at which the fuse element melts when there is a current surge is called fusing current (If) given as [2]

Fu sin g current , I f  k

3

 d       (1)

Where: If - Fusing current k - Constant, varies for different conductor material d - Diameter of the strip Fusing current depends on the following factors: 1) 2) 3) 4) 5)

The material of the fuse wire The length of the fuse wire Diameter of the wire The shape of the cross section of the fuse element Type of enclosure

Fusing factor – this is defined as the ratio of the minimum fusing current to the rated current capacity of the fusing element. When the overcurrent is high, its temperature will rise and when it reaches the melting point it melts. The energy in the fuse wire/element(E) during melting is 2

 R t          (2)

E  If

f

Where: Rf – resistance of the wire strip ∆t – time for which the current persists Response time- the melting and clearing time of a fuse depends on the magnitude of the overcurrent and is usually specified by a time current curve. When excess current flows through the strip, it should be able to isolate the circuit quickly.

1.2 Pareto Analysis

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2nd International Conference On Engineering Research & Development: 1529 Innovations (15th – 17th April 2008), Benin City, Nigeria Pareto analysis uses the principle that problem solvers should focus on 20% of factors causing 80% of the problems instead of the 80% of factors causing only 20% of the problems. It is also called the 80/20 rule. The numbers 80 and 20 are not absolute [3] .In other words, it can also be stated that by doing 20% of work you can generate 80% of the advantage of doing the entire work [4].This principle was named after Vilfredo Pareto, an Italian sociologist and economist in the 19th century who observed that 80% of Italy’s wealth was owned by 20% of the population [5]. Pareto, found that a large percentage of wealth was concentrated in a small proportion of the entire population. This methodology has been employed in the design and optimization of industrial processes [6]. This analysis can be applied in electric power distribution systems. It is a principle centered on ‘significant few and the insignificant many’. Large proportion of Electric power distribution system failures are due to a small number of frequently occurring causes[7].Therefore, if we analyse the failure data, we can solve the largest proportion of the overall reliability problem with the most economical use of resources. A large number of failure causes can be eliminated from further analysis by creating a Pareto plot of the failure data [7]. The Pareto Principle says in essence that a problem can be solved by focusing on solving the most frequently occurring causes. Pareto analysis is used to focus on problems solving, so that areas creating most of the issues and difficulties are addressed first. A small proportion of causes produce a large proportion of result. Pareto analysis is carried out in the following sequence: 1) 2) 3) 4) 5) 6) 7)

Gather data on the frequency of the causes of faults Rank the causes from the most to the least important (causes and effect analysis) calculate the cumulative percentage Draw a horizontal axis (x) that represent the different causes ordered from the most to least frequent. Draw a vertical axis (y) with percentage from 0 – 100% Construct a bar chart based on the percentage of each case. Construct a line graph of the cumulative percent. Draw a line from 80% on the y-axis to the line graph, and the drop the line to the x-axis. This line separates the important causes from trivial ones.

It is the discipline of organizing the data that is central to the success of using Pareto Analysis. Once calculated and displayed graphically, it becomes a selling tool to the improvement team and management, answering the question why the team is focusing its energies on certain aspects of the problem [8]. The Pareto analysis will help the Power Holding Company of Nigeria (PHCN) in decision-making on where in feeder pillars effort and money need to be applied in order to improve reliability, by solving the most critical problems first.

2. METHODOLOGY In the course of the research, four feeder pillars where taken as case study. They are: Uwasota no.2, Edaiken, Holex and Holy Rosary feeders. Power outage data due to feeder pillar faults were collected between January, 2005 and September, 2007 from Power Holding Company of Nigeria (PHCN), Ugbowo district office, Edo State, Nigeria for four feeder pillars [9].The information on fault occurrences were precise, it contained information on, the date a fault occurred, the feeder pillar, type of fault, and action

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2nd International Conference On Engineering Research & Development: 1530 Innovations (15th – 17th April 2008), Benin City, Nigeria taken after routine check of the conditions of each feeder pillar. The number of times each cause of fault occurred in the feeder pillars were summed up and tabulated. These data are presented in Table 1.The causes where ranked from the most to the least important.

Table 1 Causes of fault occurrences in Edaiken 2, Uwasota 2, Holex and Holy Rosary Road feeder pillars Feeder Pillar Causes of faults in feeder pillar Edaiken 2 Uwasota 2 Holex Holy Rosary Total Wrong fusing Overloading occurring with wrong fuse in place line to line fault with wrong fuse in place line earth with wrong fuse in place Short circuit in feeder pillar

32

46

66

53

197

16

18

35

21

90

7

16

13

17

53

4

6

4

9

23

2

3

6

2

13

1

2

1

4

1

1

0

1

Partial contact at incoming unit 1 Partial contact at outgoing unit 0

The frequency of occurrence of each fault in the various feeders were computed using equation (3)

F

n              (3) t

Where: F, frequency of occurrence n, Number of times a fault occurred . t, Total number of faults

Using Edaiken 2 feeder pillar in Table 1,number of times wrong fusing fault occurred=32 and the total faults in the feeder pillar=62.Thus,using equation (3),we have

Frequency of occurrence 

32  51.61 62

Similarly, all faults were considered in this feeder pillar and other feeder pillars. The results are presented in Table 2.Also presented in Table 2 are the cumulative frequencies (CF) of each cause of a fault.

Causes

of

Edaiken 2

Uwasota 2

Holex

Holy Rosary Road

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2nd International Conference On Engineering Research & Development: 1531 Innovations (15th – 17th April 2008), Benin City, Nigeria faults/faults in the feeder pillar Wrong fusing overloading line to line fault line earth Short circuit in feeder pillar Partial contact at outgoing unit Partial contact at incoming unit total

F 51.61 25.81

CF 51.61 77.42

F 50.55 19.78

CF 50.55 70.33

F 51.97 27.56

CF 51.97 79.53

F 51.46 20.39

CF 51.46 71.84

11.29 6.45

88.71 95.16

17.58 6.59

87.91 94.51

10.24 4.72

89.76 94.49

16.50 8.74

88.35 97.09

3.23

98.39

3.30

97.80

3.15

97.64

1.94

99.03

1.61

100.00

1.10

98.90

1.57

99.21

0.97

100.00

0.00 100.0

100.00

1.10 100.00

100.00

0.79 100.00

100.00

0.00 100.00

100.00

Table 2 The frequency (F) and cumulative frequency (CF) of the feeder pillars 3. RESULS AND DICUSSIONS The Pareto analysis discussed in the introduction was applied to Table 2 and the Pareto’s charts of Figures 4, 5, 6, and 7 for Edaiken 2, Uwasota 2, Holex and Holy Rosary feeders respectively were obtained. cf

60

120

50

100

40

80

Figure 4 Edaiken 2 feeder Pareto’s chart

60

20

40

10

20

0

.

frequency

30

cummulative frequency

frequency

freq

Figure 5 Uwasota 2 feeder Pareto’s chart

cf

60

120

50

100

40

80

30

60

20

40

10

20

0 Vital few

trivial many

causes of fa ults

0

0 Vital few

trivial many

cause s of faults

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cummulativefrequency

freq

2nd International Conference On Engineering Research & Development: 1532 Innovations (15th – 17th April 2008), Benin City, Nigeria

cf

60

120

50

100

40

80

30

60

20

40

10

20

0

cummulativefrequency

frequency

freq

0 Vital few

trivial many

ca use s of fa ults

Figure 6 Holex feeder Pareto’s chart cf

60

120

50

100

40

80

30

60

20

40

10

20

0

cummulative frequency

frequency

freq

0 Vital few

trivial many

causes of fa ults

Figure 7 Holy Rosary Road feeder Pareto’s chart

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2nd International Conference On Engineering Research & Development: 1533 Innovations (15th – 17th April 2008), Benin City, Nigeria Figure 8 shows the colour interpretation of the Pareto charts wrong fusing overloading line to line faults line to earths faults short circuit in feeder pillar partial contact in outgoing unit partial contact in incoming unit

Figure 8 Pareo charts colour interpretation The fault causes to the left of each vertical line on the charts show the major causes (vital few) responsible for most of the faults that occur in the feeder pillar. The vital few faults are:

Edaiken 2: wrong fusing overloading Uwasota 2: Wrong fusing Overloading Line-to-line fault Holex: wrong fusing Overloading Holy Rosary: Wrong fusing Overloading Line-to-line fault

% reduction 

nS x100        (4) t

Where nS is the sum of fault causes to the left of the vertical line in the Pareto charts. Using equation (4) from the foregoing, it is clear that solving wrong fusing and overloading in the Edaiken 2 will reduce the faults in the feeder by

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2nd International Conference On Engineering Research & Development: 1534 Innovations (15th – 17th April 2008), Benin City, Nigeria Percentage reduction

48 x100  77.42% 62

Similarly, for: Uwasota 2 feeder pillar: 87. 91% Holex feeder pillar: 79.53% Holy Rosary feeder pillar: 88.35%

In situations like this when the vital few causes have been revealed and the management want take action based on this analysis, it would be very clear to the management causes to be addressed first, i.e. the few vital causes which that need special attention in order to reduce faults that occur in the feeder pillar. If we correct these few key causes, we will have a greater probability of success.In the feeder pillar these major causes wrong fusing, Overloading, Line-toLine faults, led to the other causes because of their adverse effect. Wrong fuses are used instead of the specified rated fuses. Due to rapid extension of these feeders without corresponding upgrade of the fuses they become overloaded resulting in frequent burn out. Also, in the cause of this work, it was observed that most of the distribution conductors are undersized. This results in increased power losses and heat in the distribution conductors. The heat leads to increase in sag which finally causes line-to-line faults. Providing solutions to all these highlighted problems, the effect of wrong fusing, overloading and line-to-line faults on distribution lines will be reduced.

4. CONCLUSION The importance of the feeder pillar to the distribution cannot be over-emphasized; hence it is necessary to ensure that it is in the best working condition at all times. Having a simplified composition, the maintenance of a feeder pillar is not very difficult compared to transformers, generators e.t.c. however, to ensure its maximum efficiency the following recommendations should be considered: External bridging of fuses with bare copper conductor, nails etc. should be discouraged. Most times bridging with bare conductor is done because of the desperate need for power when the rated fuses are burnt out, or when the electricity company is under pressure from consumers. The feeder pillar should be cage with fence; only authorized individual can have access to the equipment. The fuses in the feeder pillars should be rated correctly with future load growth considered. Overloaded feeder pillars should be upgraded. The distribution lines should be traced at intervals checking conditions of the lines. The results obtained using Pareto Analysis shows that eliminating wrong fusing and overloading in Edaiken 2 and Holex feeder pillars will reduce faults by 77.42 and 79.53% respectively while eliminating wrong fusing, overloading and line-to-line faults in Uwasota 2 and Holy Rosary feeder pillars will reduce faults by 87.9 and 88.35% respectively. The major limitation Pareto’s principle is that it only shows the analyst which vital causes to concentrate on, but does not gives solution to those causes. Despite its limitation, Pareto’s principle has made it easy to identify the major problem solving tool that makes management tasks easy.

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2nd International Conference On Engineering Research & Development: 1535 Innovations (15th – 17th April 2008), Benin City, Nigeria 6. ACKNOWLEDGEMENT The authors acknowledge the members of staff, Power Holding Company of Nigeria (PHCN), Ugbowo district office, Edo State, Nigeria for making data available for this work. 7. REFERENCES (1) E.A Ogujor “Reliability Assessment of Electric Power Distribution: A case study of 2 x 15MVA, 33/11kV Ugbowo Injection Substation” PhD Thesis: University of Benin, Benin City. Nigeria.2007 (2) T. Wildi “Electrical Power Technology” John Wiley and Sons,USA.1981. (3) S. Leavengood and J.Reeb “Pareto Analysis and Check Sheets” Oregon State University. United States of America.http://www.wood.orst.edu,2002. (4) Mindtools Ltd “Pareto Analysis” http://www.mindtools.com,2007. (5) J. Strickland “Pareto Analysis in Seven steps”. Sevenrings Ltd. United Kingdom.http://www.sevenrings.co.uk,2006. (6) P.D Haaland “Experimental Design in Biotechnology”. Marcel Decker Inc., .New York and Basel,1989. (7)P.D.T O`Connor “Practical Reliability Engineering” 4th ed. John Wiley & Sons Ltd, England.pp1-513, 2002. (8) pareto's law (80-20 rule) www.managers-net.com (9) PHCN (Jan, 2005 and Sept., 2007.) PHCN daily power outage data and operational logbooks of Ugbowo district, Benin City. Nigeria.

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2nd International Conference On Engineering Research & Development: 1536 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08165) DESIGN AND PARAMETER ESTIMATION OF A THREE PHASE INDUCTION MOTOR USING A USER - INTERACTIVE COMPUTER PROGRAMME

E.U. UBEKU and E. A. OGUJOR Department of Electrical/Electronic Engineering University of Benin, Benin City, Nigeria

Abstract This paper presents the use of a user-interactive MATLAB programme for the design and the parameter estimation of a three-phase induction motor (TPIM) using a per phase equivalent circuit model. Optimum design parameters such as the bore diameter, the rotor diameter, the slot dimensions, the air-gap length and the performance curves are obtained by iterative procedure of a design algorithm. The performance curves of the TPIM i.e., torque and efficiency are drawn from the model’s per phase parameters and then analyzed for different number of poles, number of slots ,varying air-gap, rated slip etc and their effect on the performance of the TPIM are analyzed and the results discussed. The results obtained were validated with similar studies carried out using finite element software FEMM. The comparison shows that the TPIM model is satisfactory. 1. Introduction The recent years has seen the development of computer based tools for the design and performance analysis of electrical machines [1]. The aim is to compute accurately the operating properties and characteristics of the machine without first constructing a prototype. There are two approaches in using a computer in the design, simulation and analysis of electric motors: - the user- interactive approach and the magnetic field approach [2, 4]. The user-interactive approach involves the development of a design algorithm based on standard machine equations and design procedures. A computer program is then written using software. Optimum design parameters are then obtained by the iterative procedure of the design algorithm. Two distinct methods exits in the field approach: domain-type and boundary-type. Domain-type formulation is the direct solution of the differential equation governing the field. The finite difference (FDM) and finite element (FEM) methods are the two most commonly used domain-type methods. The boundary-type formulation is the solution of boundary integral equations on which the boundary element method (BEM) is based. The purpose of this paper is to describe a user-interactive computer based approach written in MATLAB software for the design and parameter estimation of a three phase induction motor and comparing the performance curve with that obtained from the field approach using free finite element software (FEMM)[3,4]. 2. Governing Design Equations

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2nd International Conference On Engineering Research & Development: 1537 Innovations (15th – 17th April 2008), Benin City, Nigeria In this section the design equations governing the dimensions of the bore diameter, axial length, core depth, and slot sizes of an m-phase induction motor will be reviewed. Taking the design of the three phase motor, from the peripheral velocity V s point of view, the bore diameter D of the motor, is given by, D 

Vs Vs  p    ns 2   f

(1)

Where, p is the number of poles, n s is the synchronous speed in rotation per seconds and f the supply

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2nd International Conference On Engineering Research & Development: 1538 Innovations (15th – 17th April 2008), Benin City, Nigeria frequency. If the velocity of the rotor is Vr then the slip s of a TPIM can be defined as [2, 5]

s

Vs  Vr Vs

(2)

Rearranging 2 and substituting into 1, the bore diameter expression then becomes Vr  p (3) D  2   1  s   f The axial length L is related to the bore diameter through the output power equation or through the ratio of the axial length and pole pitch. Using the ratio of the axial length and pole pitch approach the expression for the axial length is given as

L

k  Vr k   D (4)  p 2  1  s   f

Where, k ranges from 0.9-1.0 [7]. The air-gap l g is a very important parameter in a machine and it is given as

l g  0 .2  2 D  L

(5)

The rotor diameter D r is given as

Dr  D  2  l g (6) The stator core height hs is the portion of the core below the teeth. If it is assumed that the flux in the core is one-half of the flux in the air-gap, then it can be expresses as [3,7] hs 



(7)

p

2  B max L

Where,  p is the amplitude of the flux linkage per pole and Bmax is the maximum flux density of the airgap whose average value is given by

Bave 

2  Bmax (8) 

The slots of a TPIM comes in different shapes, the size of the slot opening W0 s depends on the number of slots, and for a 36-slot motor it is given as W0 s  0.0381  0.0175  D (9) The depth of the slot’s tip d 0 s can be approximately taken as 0.075cm, and the depth of the mouth is given as (10) d 1s  s  d 0 s Where, s ranges, from 1.0 to 1.5. The width of the stator tooth, Wts depends on the number of poles, for a 2-pole motor it is given as

Wts  (1.10  0.032  D) 

D Ss

(11a)

And for a 4-pole and above it is given as

Wts  (1.27  0.035  D) 

D Ss

(11b)

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2nd International Conference On Engineering Research & Development: 1539 Innovations (15th – 17th April 2008), Benin City, Nigeria The bottom of stator slot could be flat or round, in this paper we are using a flat bottom slot in the design, and thus the expression for the size of the bottom of the slot is given as

W3 s  W1s  2  d 4 s  tan  (12) Where W1s is given as  [ D  2( d 0 s  d1s )] W1s   Wts (13) Ss (14) d4s  0.5 (Do  D)  (d0s  d1s  dcs )

180 0 and   Ss D o  D  2  d cs  2  d ss

(15)

Where Do is the outer diameter of stator laminations and d ss is the depth of the stator slots which is given as d ss  d 4 s  d 0 s  d1s (16) Like the stator slots, the trapezoidal slot of the rotor will be looked into in this design. The rotor tooth width Wtr is given as

Wtr 

0.95  Wts  S s Sr

(11)

The rotor slot opening Wor can be taken as [3]

W0 r  0.075 mm While the depth d or of the opening should be assumed as

d 0 r  0.075 mm The bottom of the rotor slot W3 r can be computed from

W3r 

  Dr  2 d r   Wtr (18) Sr

The width of the bar in the rotor slot is given as (19) W b  W 3r  C t Where C t is the tangential clearance which could be taken as 0.025 mm. The depth of the rotor slot d 4 r is given as

d 4 r  0.25  0.03D (20) Thus the depth of the bar d b can be computed from, d b  d 4 r  C r (21) Where, C r is the radial clearance and could be taken as 0.015 mm in this design [3]. The current in the windings can be replaced by a fictitious and infinitely thin layer of current distributed over the surface of the stator facing the air gap. This current is called the “current sheet”. The current sheet strength, i.e., the amount of current per unit stator length is given as[2],

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2nd International Conference On Engineering Research & Development: 1540 Innovations (15th – 17th April 2008), Benin City, Nigeria 2 2  m  kw  N cs  I 1 (22)  D Where J ms the current is sheet strength (amp/meter); m is the number of phases of the motor; k w is the J ms 

winding factor, defined below; N cs is the number of turns per slot and I 1 is the RMS value of the input current. The input current is obtained from the input power to the stator windings. The winding factor k w is defined as the product of the pitch factor k p and the distribution factor k d and is given by

   sin   2m   kw  (23)     q1  sin  2 mq 1   Where, q1 is the number of slots per pole per phase in the stator iron core. 3. Performance Parameters Estimations A reasonable model of an induction motor was first been identified before the performance parameters in that model can be deduced. The reasonable model to assume is the one shown in figure 1. This model is meant to represent one phase of an induction motor operating in steady state. The following parameters can be obtained from the circuit [3, 4, 7, and 8].

Fig 1: Per-phase induction motor model i) Per-phase stator resistance R1 This is the resistance of each phase of stator windings and is given as

R1   2  2  lce   J 1 

N1 I1

(24)

Where,  is the volume resistivity of the copper wire used, J 1 the stator current density, N 1 the number of turns per phase and l ce the length of end connection given as,

l ce 

 p D 180 0  p

(25)

And  p is the coil span, normally taken as 180 0 ii) Per-phase stator-slot leakage reactance X 1

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2nd International Conference On Engineering Research & Development: 1541 Innovations (15th – 17th April 2008), Benin City, Nigeria The per phase stator slot leakage reactance is given as  (26) X 1  8 fN 12 L 

 p  q1 

Where,  is the permeance and for a two layer slot winding it is given as  2  d4 s d 2 s 2  d1s d        0s  (27)  3  W3s W3s W3s  W0s  W0s  Where, d is and Wis i  0,1,.... are stator slot dimensions as shown in figure 1.

Fig 2: Stator slot (flat bottom) iii) Per-phase magnetizing reactance X m The per phase magnetizing reactance is given by

Xm 

V1 Im

(28)

Where, I m is the magnetizing current and V1 is as defined below. iv) Per-phase rotor resistance R2

 l 2D R2    S r2  b  2 e  S r Ab p Ar

   

(29)

Where, Ab and Ar are the area of the bar and end rings respectively and De is the end ring mean diameter. The per phase rotor resistance is referred to the stator and is given as R (30) R2ref  4mN12 kw 22 Sr From the per phase parameters the impedance of the TPIM can be computed as jR2 ref X m / s (31) Z  R1  jX 1  R2 ref / s  jX m The performance characteristics of the TPIM can be obtained from the per phase parameters as given below. The real input power to the stator winding is given as Pin  mV 1 I 1 cos  (32)

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2nd International Conference On Engineering Research & Development: 1542 Innovations (15th – 17th April 2008), Benin City, Nigeria Where, V1 and I 1 are the rms input phase voltage and current respectively and  is the phase angle between V1 and I 1 . And the developed torque Ts is

Ts 

mI 22 ( R2 ref / s) Vr 

(33)

The developed mechanical power in an m-phase induction motor is given as

Pout  TsVr

(34) And the actual input power is given as Pin  Pout  mI 22 R 2 ref  mI 12 R1 (35) The efficiency of the motor is thus given as [3, 7, 8]



Pout Ts   Vr  Pin mV1 I1 cos

(36)

The rated rms input phase current can be computed from equation 12 as Ts V r (37) I1  mV1 cos  With the torque, rotor velocity and power supply values as an input parameters and assuming an initial value for  cos  , the design and performance parameters can be estimated. A modified design algorithm was written and was implemented using the MATLAB® m-file [2, 10] 4. Performance Curves and Analysis of Results. The performance studies where carried out by assuming the following: Line voltage = 400 Volts Frequency = 50Hz. Slip=10% Rated rotor velocity = 15m/s Target torque = 300 Nm/rad Rotor Ampere-Turn =85% Slot Ampere-Turn.

i. Effect of varying the number of poles  p  . Figure 3 and 4 shows the performance of the machine when the number of poles is been varied. The efficiency of the motor decreases, with increase in the number of poles as shown in fig 3 while the standstill torque increases as the number of poles increases as shown in fig 4. Thus a two pole TPIM is more efficient than a 4- or 6- or an 8-pole TPIM.

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2nd International Conference On Engineering Research & Development: 1543 Innovations (15th – 17th April 2008), Benin City, Nigeria

Fig 3: Effect of varying poles on the efficiency of a TPIM plotted against rated rotor velocity.

Fig 4: Effect of varying poles on the standstill torque of a TPIM plotted against rated rotor velocity [2, 4].

 

ii. Effect of varying the air-gap length l g

Figure 5 and 6 shows the performance of the motor with varying air-gap, the number of poles and g 1 were kept at 2 and 1 repectively. The length of the air-gap is a very important parameter in machine design. The air-gap, account for about, 90% of the total magneto-motive force (mmf), of a motor. The efficiency and the out torque of TPIM deceases when a large air-gap is used in design as shown in figure 5 and 6 respectively. Thus the air-gap should be as small as is mechanically possible [2,5]

Fig 5: Effect of large air-gap on the efficiency of a TPIM plotted against the rated rotor velocity.

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2nd International Conference On Engineering Research & Development: 1544 Innovations (15th – 17th April 2008), Benin City, Nigeria

Fig 6: Effect of large air-gap on the torque of TPIM plotted against the rated rotor velocity.

iii. Effect of increasing the number of slot through g 1 . Figure 7 and 8 shows efficiency and torque plots when the number of slot is increased through g1 (number of slots per pole per phase) instead of through the poles, the number of pole was fixed at 2. Figure 7 shows that the efficiency of the motor remains constant with increasing g 1 and the impedance increases from 4.0981+j5.2199 at g 1  1 to

5.9993+j2.3307  at g 1  5

g 1  7 .This shows TPIM performs better with large number of slots. Figure 8 shows that the output torque decreases as g 1 increases, it can be seen that the output torque close to the desired torque is possible when the number of slots are increases through g 1 . before deceasing to 4.6316+j1.3104  at

Fig 7: Effect of increasing the slots through g 1 on the efficiency of TPIM plotted against the rated rotor velocity.

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2nd International Conference On Engineering Research & Development: 1545 Innovations (15th – 17th April 2008), Benin City, Nigeria

Fig 8: Effect of increasing the slots through g 1 on the torque of TPIM plotted against the rated rotor velocity. 5. Conclusion With the user-interactive computer programme approach it is possible to design the stator and rotor core a TPIM motor. An increase in the number of poles or the length of the air-gap reduces the efficiency of the TPIM. A 2-pole motor is more efficient, while a small air-gap provides a better torque and also improves efficiency.

6. Reference [1]. Riaz, M (2005) “Simulation of Electric Machine and Drive System using Matlab and Simulink”. http://www.ece.umn.edu/users/riaz [2] .Sarveswara, P.B (2005)”Design of a Single Sided Linear Induction Motor (SLIM) using a User Interactive Computer Program”,Msc thesis, Faculty of the Graduate School, University of MissouriColumbia. [3]. Sawhney, A.K “Principle of Electrical Macine Design” [4]. Meeker, D (2004) “Induction Motor Example” [email protected] [5]. Okoro,O.I et al (2006) “Basic Principles and Functions of Electrical Machines” The Pacific Journal of Science and Technology,Volume 7. Number1. [6]. Deshpande, M.V () “Design and Testing of Electric Machines” Second Edition, Wheeler Publishing, Allahabad. [7]. Matsch, L.W (1972) “Electromagnetic and Electromechanical Machines” Dun-Donnelley Publisher, New York. [8]. Matlab6.5 http://www.mathworks.com

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2nd International Conference On Engineering Research & Development: 1546 Innovations (15th – 17th April 2008), Benin City, Nigeria

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2nd International Conference On Engineering Research & Development: 1547 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08269) ANALYSIS OF FORGING PROCESS BY THE WEIGHTED-RESIDUAL FINITE ELEMENT METHOD John A. Akpobi and Christian O. Edobor Production Engineering Department, University of Benin, Benin City, Nigeria. Abstract This paper reports an examination of the stresses and pressure fields set up at various cross-sections of a material during forging operation by the weighted residual finite element method. We present the numerical solution to the one-dimensional differential equation which describes the pressures and stresses exerted on a forging. In preparation for the numeric, we split the blank into a finite number of elements and apply the Bubnov-Galerkin weighted residual scheme to obtain the weighted integral form; the finite element model is then developed from this weighted integral form which is solved to yield a threeparameter polynomial solution. Using a series of examples, we proceed to show that the weighted residual finite element method is capable of accurately predicting the pressures and stresses in an open die forging operation. Keywords: Forging process; Bubnov-Galerkin weighted residual scheme; Finite element method. 1. Introduction Forging is one of the oldest, and still remains one of the fastest, method of shaping metals and other materials. The need therefore arises to critically and numerically analyze the drawing operation in order to predict the various stresses and pressure fields set up at a particular cross-section of a given blank material. The estimated pressures and stresses can thus be compared with the strength of the material and this aids the determination of the smallest pressure needed to cause the bulk plastic flow of the material. Being a very fundamental and versatile metal forming process, a large number of investigations into forging process exist in literature. J. Navarrete et. al. (2001) used a dimensional analysis approach to determine the die forging stress in open die forging. They proposed five dimensionless groups from the process variables in an attempt to simplify the forging stress determination. T. J. Nye et. al. (2001) carried out a real time process characterization of open die forging for adaptive control. They demonstrated how process information can be used in real time to derive the actual spread coefficient for a given workpiece as it is being formed. A. Alfozan and J. S. Gunasekera (2003) proposed an upper bound element technique approach to the process design of axisymmetric forging by forward and backward simulation. In this study, we employ the weighted residual finite element method, as a numerical tool, to determine the stresses and pressures set up during an open die forging operation. Due to symmetry, analysis is carried out on half the blank. The blank is divided into a finite number of elements and approximations are carried out over each element using the Lagrange interpolation functions. The results of these approximations are assembled into the global coefficient matrix which is a part of the finite element model. This model is solved by employing simple matrix algorithm to obtain a three-parameter polynomial solution. This solution applies to any open die forging problem since it is in terms of the three most important parameters in forging: coefficient of friction, ì, height of forging, h, and half the length of the forging, L. hence numerical values could be obtained at various nodes by inserting the values of ì, h and L or R as applies to the particular open die forging problem. 2. Plane Strain Forging

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2nd International Conference On Engineering Research & Development: 1548 Innovations (15th – 17th April 2008), Benin City, Nigeria a. Formulation of Governing Equation

p

x  x  d x

x

h

x p dx

Figure 1: Free body diagram of plain strain forging process The equilibrium equation of a small element of width dx in the x-direction is given as:

  x  d x  Bh   x Bh  2x Bdx  0

(1)

 x Bh  Bhd x   x Bh  2 x Bdx  0 Bhd x  2 x Bdx  0 d x 2 x  0 dx h

(2)

Generally we consider a forging process where interfacial friction is involved and as such we assume Coulumb friction with constant coefficient of friction. Hence  x  p (3) Put equation 3 into equation 2 to get:

d x 2p  0 dx h

(4)

from Tresca’s yield criterion

1  3  0  2k

(5)

The principal stresses are:

1   x and 3   p

(6)

Therefore;

 x  p   0  2k We also have that:

(7)

d x dp  dx dx

(8)

Substitute equation 8 into equation 4:



dp 2p  0 dx h

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2nd International Conference On Engineering Research & Development: 1549 Innovations (15th – 17th April 2008), Benin City, Nigeria or

dp 2p  0 dx h

(9)

b. Weighted Integral Formulation The weighted integral form of equation 9 is obtained by multiplying it by the weight function, W and integrating over the domain enclosing an element with respect to x.

dp 2p   dx dx h 

(10)

dp 2   wp dx dx h 

(11)



i.e. 0   w







or 0   w





An examination of equation 11 shows that the solution and hence the approximation function should be once differentiable with respect to x. hence the Lagrange family of interpolation functions can be used satisfactorily. let us assume that the solution p is approximated as follows: n

p  p e   p ej  ej  x 

(12)

j1

We here adopt the Bubnov-Galerkin weighted-residual method in which it is assumed that the weight function is equal to the interpolation function. i.e. w   ie (13) substitute equation 12 and 13 into 11:

  d n e e 2 e n 0     ie Pj  j   i  Pj ej  dx  dx j1 h j1   or n  xA  d e 2 e e   e 0       ie j   i  j  dx  p j  xB h  dx   j1 

(14)

we recast equation 14 in the form: n

0    k ije  p ej 

(15)

or  k ije  pej  0

(16)

j1

 

where xB  d ej 2 e e  k ije     ie   i  j dx  xA  dx h  

Equation 16 is the weighted-residual finite element model of equation 9 In order to ensure high accuracy, we use a mesh of four quadratic elements (9 nodes). The interpolation functions for a quadratic element are:

x   2x  4x  x   ie  1  e  1  e  ,  e2  e 1  e h  h  h  h  But h e  L 4

x  2x   e  and  3   e 1  e  h  h  

(17)

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2nd International Conference On Engineering Research & Development: 1550 Innovations (15th – 17th April 2008), Benin City, Nigeria 4x  8x   4x   8x  e 16x  4x  e 1e  1   1   ,  2  1   and  3   1   L  L L  L  L  L 

(18)

Also

d 3e 4 16x  L  d1e 4 16x  3L  d e2 16  8x  L     , and dx L2 dx L2 dx L2

(19)

Hence L

 4x   8x  4 16x  3L  2  4x  2  8x  2  K    1    1   1      1   dx L  L L2 h  L   L    0  30h  4L e K11  60h 4

e 11

L e 12

K 

4



 1  0

4x   8x   16  8x  L   2  4x   8x  16x  4x    1    1      1   1   dx L  L  L2 L  L L  L    h 

 40h  2L e K12  60h L e 13

K 

4



 1  0

4x   8x   4 16x  L   2  4x   8x   4x  8x     1    1       1      1    dx L  L  L2 L  L  L  L     h 

 10h  L e K13  60h L

4

16x  4x   4 16x  3L   2 16x  4x    4x   8x      1   1    1    1    dx L  L   L2 L    L  L     h L  0  40h  2L K e21  60h L 2 4 16x  4x   16  8x  L   2  16x  4x    e K 22      1    1    dx 2 L L L h L L          0   16L K e22  60h e 21

K 

 

L

4

16x  4x   4 16x  L   2 16x  4x   4x  8x      1   1     1    dx L  L   L2 L   L  L     h L  0  40h  2L K e22  60h e 23

K 

 

L e 31

K 

4

 4x 

   L 1 

0  10h  L e K 31  60h

8x    4 16x  3L   2  4x  8x     4x   8x       1      1       1    dx L   L2 L   L  L     h  L 

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2nd International Conference On Engineering Research & Development: 1551 Innovations (15th – 17th April 2008), Benin City, Nigeria L e 32

K 

4

 4x  8x    16  8x  L   2  4x  8x    16x  4x       1       1      1    dx 2 L L L h L L L L               

   0

40h  2L e K 32  60h L 2 4  4x  8x    4 16x  L   2  4x  8x    e K 33      1         1     dx  L  2 L L L h L             0  30h  4L e K 33  60h The finite element model over an element becomes: e  30h  4L 40h  2L 10h  L   p1  0  1    p e   0   40h  2  L 16  L 40h  2  L  2   60h   10h  L 40h  2L 30h  4L   p3e  0 

(20)

The assembled equations for a four quadratic-element mesh are given as: 10h  L 0 0 0 0 0 0  30h  4L 40h  2L   p1  0   40h  2L   p  0  16L 40h  2L 0 0 0 0 0 0   2    10h  L   p 3  0  40h  2L 8L 40h  2L 10h  L 0 0 0 0      0 0  40h  2  L 16  L 40h  2  L 0 0 0 0   p 4  0  1    p 5   0  40h  2L 0 0 16h  L 8L 40h  2L 10h  L 0 0 60h            0 0 0 0 40h 2 L 16 L 40h 2 L 0 0    p 6  0   0 0 0 0 10h  L 40h  2L 8L 40h  2L 10h  L   p 7  0       0 0 0 0 0 0 40h  2L 16L 40h  2L   p8   0    0 0 0 0 0 0 10h  L 40h  2L 30h  4L   p9   0  

(21) The boundary condition is: At x  L  x  0 But  x  p   0  2k Therefore x  L, p9   0  2k The assembled equations, using the first eight equations, become: 10h  L 0 0 0 0 0 0  30h  4L 40h  2L   p1     40h  2L  p    16L 40h  2L 0 0 0 0 0 0   2    10h  L   p3    40h  2L 8L 40h  2L 10h  L `0 0 0 0      p 0 0 40h  2L 16L 40h  2L 0 0 0 0  1      4 0        p 5  60h  40h  2L 10h  L 0 0 10h  L 8L 40h  2L 0 0 60h         p 40h  2L 0 0 0 0 16L 40h  2L 0 0   6      0 0 0 0 10h  L 40h  2L 8L 40h  4L   p 7  10h   L         0 0 0 0 0 0 40h  2L 16L   p8    40h  2L 

(22) Solving equations 22 gives rise to the following nodal values. Let v  L

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2nd International Conference On Engineering Research & Development: 1552 Innovations (15th – 17th April 2008), Benin City, Nigeria p1 v8  64hv 7  1856h 2 v6  31744h 3 v5  349696h 4 v 4  2539520h 5 v3  11878400h 6 v 2  32768000h 7 v  40960000h8  8 0 577v  4896hv 7  72000h 2 v 6  434688h 3 v5  2643456h 4 v 4  9953280h 5 v3  28262400h 6 v2  49152000h 7 v  40960000h8 p 2 1 v8  56hv 7  1232h 2 v 6  12160h 3 v5  13568h 4 v 4  931840h 5 v3  9932800h 6 v2  45056000h 7 v  81920000h8   8 0 2 577v  4896hv 7  72000h 2 v 6  434688h 3 v5  2643456h 4 v4  9953280h 5 v3  28262400h 6 v 2  49152000h 7 v  40960000h8 p3 3v8  120hv7  1952h 2 v 6  14976h 3 v5  39936h 4 v 4  71680h 5 v 3  614400h 6 v 2  12288000h 7 v  40960000h8  8  0 577v  4896hv 7  72000h 2 v 6  434688h 3 v5  2643456h 4 v 4  9953280h 5 v3  28262400h 6 v 2  49152000h 7 v  40960000h8 p 4 1 5v8  200hv 7  2768h 2 v6  14976h 3 v5  18688h 4 v 4  194560h 5 v 3  2355200h 6 v 2  4096000h 7 v  81920000h 8   8 0 2 577v  4896hv 7  72000h 2 v 6  434688h 3 v5  2643456h 4 v4  9953280h 5 v3  28262400h 6 v 2  49152000h 7 v  40960000h8 p5 17v8  400hv 7  3520h 2 v 6  13568h 3 v5  62976h 4 v4  389120h 5 v3  409600h 6 v 2  8192000h 7 v  40960000h 8   0 577v8  4896hv 7  72000h 2 v 6  434688h 3 v5  2643456h 4 v 4  9953280h 5 v3  28262400h 6 v 2  49152000h 7 v  40960000h8 p 6 1 29v8  696hv7  3536h 2 v 6  12672h 3 v5  151808h 4 v4  296960h 5 v3  5836800h 6 v2  36864000h 7 v  81920000h 8   0 2 577v8  4896hv 7  72000h 2 v 6  434688h 3 v5  2643456h 4 v4  9953280h 5 v3  28262400h 6 v 2  49152000h 7 v  40960000h8 p7 99v8  744hv 7  3744h 2 v 6  32640h 3 v5  162816h 4 v4  1198080h 5 v3  8806400h 6 v2  28672000h 7 v  40960000h 8  0 577v8  4896hv 7  72000h 2 v 6  434688h 3 v5  2643456h 4 v 4  9953280h 5 v3  28262400h 6 v 2  49152000h 7 v  40960000h8 p8 1 169v8  1352hv 7  9264h 2 v 6  240768h 3 v5  1635072h 4 v 4  9615360h 5 v3  34508800h 6 v 2  7782400h 7 v  81920000h 8   0 2 577v8  4896hv 7  72000h 2 v 6  434688h 3 v5  2643456h 4 v4  9953280h 5 v3  28262400h 6 v 2  49152000h 7 v  40960000h8 p9 1 0

(23) The stresses are obtained by substituting the values of the pressures into the equation:

 x  0  p The pressure distribution over each element is obtained thus:

p  x   p11  p 2  2  p3 3 p  x   p3 3  p 4  4  p5  5 p  x   p5 5  p 6 6  p 7  7 p  x   p 7  7  p8  8  p 9  9

L  4   L L  for  x  4 2   L 3L  for  x  2 4   3L for xL 4 

for 0  x 

(24)

The exact solution to equation 9, as adopted from P. C. Sharma (2003), is given as: 2  L x  p eh 0

(25)



2

Also  x   0 1  e h



Lx 

 

(26)

Example Consider a plain strain forging operation in which h  3.00mm ,   0.25 and of cross-section 100mm  80mm . Substituting these values into equation 23 yields:

Table 1: Comparison of finite element solution and exact solution for a plain strain forging operation.

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2nd International Conference On Engineering Research & Development: 1553 Innovations (15th – 17th April 2008), Benin City, Nigeria x (mm)

Finite element solutions Pressure (p)

Exact solutions Pressure (p) 5.294

Stress(  ) (compressive) 4.294

0

5.2147

Stress (  ) (compressive) 4.2147

1.25

4.2326

3.2326

4.299

3.299

2.50

3.4431

2.4431

3.490

2.490

3.75

2.7876

1.7876

2.834

1.834

5.00

2.2756

1.2756

2.301

1.301

6.25

1.8347

0.8347

1.868

0.868

7.50

1.5065

0.5065

1.517

0.517

8.75

1.2062

0.2062

1.232

0.232

10.00

1.0000

0

1.000

0

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2nd International Conference On Engineering Research & Development: 1554 Innovations (15th – 17th April 2008), Benin City, Nigeria 6

5

Forging Pressure (p)

4

3

2

1

0 -15

-10

-5

0

5

10

15

Distance from center of blank (x) Finite Element Solution

Exact Solution

Figure 2: Graphical comparison of the friction hills of the exact solution and the finite element solution. 3. AXISYMMETRIC FORGING óè

dr r (r+dr)dè

rdè dè

ór+dór

ór ôzr

óè p ôzr

h

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2nd International Conference On Engineering Research & Development: 1555 Innovations (15th – 17th April 2008), Benin City, Nigeria Figure 3: Free body diagram of an axisymmetric forging process.

We assume that r and  are constant throughout the disc thickness. The radial equilibrium of the element requires that:

d    2rddr  0  2   d   r hrd   r hdrd  d r hrd  d r hdrd   r hrd  2 hdr sin    2rddr  0  2   d  d Taking sin    2  2  r hrd   r hdrd  d r hrd  d r hdrd   r hrd    hdrd  2rddr  0  r hdr  d r hr  d r hdr    hdr  2 rdr  0

 r  dr  h  r  dr  d  r hrd  2 hdr sin 

(27)

(28)

(29)

Ignoring the products of infinitesimals:

 r hdr  d r hr    hdr  2rdr  0

(30)

Since the disc is axisymmetric, it follows that: (31)

 r  

 r hdr  d r hr  r hdr  2rdr  0 d r hr  2rdr  0 d r 2  0 dr h

(32)

Now we consider the von Mises condition 2

2

2o 2   1  2     2  3    3  1 

2

(33)

We take  r ,   and  z as the principal stresses, we have that 2

2

2

2

2

2

2o 2    r   z    z         r  But  r  

2o 2    r   z     z   r    r   r  This yields  o   r   z Also  z   p

(34)

o   r  p Which implies that

d r dp  dr dr

(35)

Substitute equation 35 into equation 32 to get

dp 2  0 dr h Also   p

(36) (37)

Put equation 37 into equation 36

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2nd International Conference On Engineering Research & Development: 1556 Innovations (15th – 17th April 2008), Benin City, Nigeria dp 2  p0 dr h

(38)

a Weight Residual Finite Element Formulation The weighted integral form of equation 38 is given as: rB

 p 2  0   w  p  dr  r h   rA

(39)

r

B  p 2  0  w  wp  dr r h  rA 

(40)

We take the outer outer diameter of the forging as R We assume that the solution is of the form n

p   p ej  ej  r 

(41)

j 1

and w   ie  r 

(42)

Where r is the radial coordinate Put equation 41 and 42 into equation 40 to yield: rB

n   n  2 0    i  p ej  ej  r    i  p ej  ej  r   dr r j1 h j 1  rA 

(43)

or

 rB  e  ej 2 e e   e 0      i   i  j  dr p j   r h j 1   rA    n

This translates to:

 K ije  pej   0

(44)

Where rB   ej 2 e e  K ije     ie   i  j  dr   r h rA   Where   r  are the radial interpolation functions put in terms of the radial coordinate r.

(45)

For a quadratic element, we have that:

1e 

 rB  rA  r  rB  rA  2r  , h

2 e

 e2 

4r  rB  rA  r  h

2 e

and  3e 

r  rB  rA  2r  h e2

(46)

Where rA and rB are the inner and outer radii respectively of an element. For a mesh of four quadratic radial elements, we have that: h e  Also for the first element, rA  0 and rB  h e 

R 4

R 4

(47) (48)

Put equation 48 into equations 46 to get:

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2nd International Conference On Engineering Research & Development: 1557 Innovations (15th – 17th April 2008), Benin City, Nigeria 1e  r  

 R  4r  R  8r  , R

2

 e2  r  

16r  R  4r  R

2

and  3e  r  

4r  R  8r  R2

Therefore

30h  4R 40h  2R 10h  R e e , k12  , k13  60h 60h 60h 40h  2R 4R 40h  2R e k12  , k e22  , k e23  60h 15h 60h 10h  R 40h  2R 30h  4R e e e k 31  , k 32  , k 33  60h 60h 60h e k11 

The finite element model over a radial element therefore is:

 30h  4R 1  40h  2R 60h   10h  R

10h  R   p1e  0      40h  2R   p e2   0  30h  4R   p3e  0 

40h  2R 16R 40h  2R

(49)

The assembled equations for a four quadratic radial element mesh are given as:  30h  4R  40h  2R   10h  R  0 1  0 60h  0   0  0   0 

40h  2R

10h  R

0

0

0

0

0

16R

40h  2R

0

0

0

0

0

40h  2R

8R

40h  2R

10h  R

0

0

0

0

40h  2R

16R

40h  2R

0

0

0

0

16h  R

40h  2R

8R

40h  2R

10h  R

0

0

0

0

40h  2R

16R

40h  2R

0

0

0

0

10h  R

40h  2R

8R

40 h  2R

0

0

0

0

0

40h  2R

16R

0

0

0

0

0

10h  R

40h  2R

  p1  0    p  0   2     p3   0  0     0   p 4  0    p 5   0  0     0   p 6  0  10h  R  p 7  0      40h  2R   p8  0  30h  4R   p 9  0  0 0

(50) The boundary conditions are:

at r  R,  r  0 Since p   0   r , p   0  2k Using the first eight equations, the condensed form of equation 50 becomes:  30h  4R  40h  2R   10h  R  0 1  0 60h   0   0  0 

40h  2R

10h  R

0

0

0

0

16R

40h  2R

0

0

0

0

40h  2R

8R

40h  2R

10h  R

`0

0

0

40h  2R

16R

40h  2R

0

0

0

10h  R

40h  2R

8R

40h  2R

10h  R

0

0

0

40h  2R

16R

40h  2R

0

0

0

10h  R

40h  2R

8R

0

0

0

0

0

40h  2R

0   p1     p    0  2     p3    0 0     0 0    p 4   0       p 0 0 60h  5      0 0  p6      40h  4R   p 7  10h  R        16R   p8   40h  2R  0 0

(51) Solving equations 51 simultaneously yields the following nodal values:

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2nd International Conference On Engineering Research & Development: 1558 Innovations (15th – 17th April 2008), Benin City, Nigeria p1 8 R 8  64h 7 R 7  1856h 2  6 R 6  31744h 35 R 5  349696h 4 4 R 4  2539520h 53 R 3  11878400h 6 2 R 2  32768000h 7 R  40960000h8  8 8 0 577 R  4896h 7 R 7  72000h 26 R 6  434688h 35 R 5  2643456h 4  4 R 4  9953280h 53 R 3  28262400h 6 2 R 2  49152000h 7 R  40960000h 8 p 2 1 8 R 8  56h 7 R 7  1232h 2 6 R 6  12160h 35 R 5  13568h 4 4 R 4  931840h 5 3 R 3  9932800h 6  2 R 2  45056000h 7 R  81920000h8   8 8 0 2 577 R  4896h 7 R 7  72000h 2 6 R 6  434688h 35 R 5  2643456h 4 4 R 4  9953280h5 3 R 3  28262400h 6  2 R 2  49152000h 7 R  40960000h 8 p3 38 R 8  120h 7 R 7  1952h 2 6 R 6  14976h 35 R 5  39936h 4 4 R 4  71680h 5 3 R 3  614400h 6  2 R 2  12288000h 7 R  40960000h8  8 8 0 577 R  4896h 7 R 7  72000h 26 R 6  434688h 35 R 5  2643456h 4  4 R 4  9953280h 5 3 R 3  28262400h 6 2 R 2  49152000h 7 R  40960000h 8 p 4 1 58 R 8  200h 7 R 7  2768h 2  6 R 6  14976h 35 R 5  18688h 4 4 R 4  194560h 53 R 3  2355200h 6  2 R 2  4096000h 7 R  81920000h8   8 8 0 2 577 R  4896h 7 R 7  72000h 2 6 R 6  434688h 35 R 5  2643456h 4 4 R 4  9953280h 53 R 3  28262400h 6 2 R 2  49152000h 7 R  40960000h 8 p5 178 R 8  400h 7 R 7  3520h 2 6 R 6  13568h 35 R 5  62976h 44 R 4  389120h 5 3 R 3  409600h 6  2 R 2  8192000h 7 v  40960000h8  0 5778 R 8  4896h 7 R 7  72000h 26 R 6  434688h 3 5 R 5  2643456h 4 4 R 4  9953280h 53 R 3  28262400h 62 R 2  49152000h 7 R  40960000h 8 p 6 1 298 R 8  696h 7 R 7  3536h 2 6 R 6  12672h 35 R 5  151808h 4 4 R 4  296960h 5 3 R 3  5836800h 6 2 R 2  36864000h 7 R  81920000h8   0 2 5778 R 8  4896h 7 R 7  72000h 2 6 R 6  434688h 3 5 R 5  2643456h 4 4 R 4  9953280h 53 R 3  28262400h 6 2 R 2  49152000h 7 R  40960000h8 p7 998 R 8  744h 7 R 7  3744h 2 6 R 6  32640h 35 R 5  162816h 44 R 4  1198080h 5 3 R 3  8806400h 6 2 R 2  28672000h 7 R  40960000h8  0 5778 R 8  4896h 7 R 7  72000h 2 6 R 6  434688h 35 R 5  2643456h 4  4 R 4  9953280h 53 R 3  28262400h 6 2 R 2  49152000h 7 R  40960000h8 p8 1 1698 R 8  1352h 7 R 7  9264h 2 6 R 6  240768h 35 R 5  1635072h 4  4 R 4  9615360h 53 R 3  34508800h 6 2 R 2  7782400h 7 R  81920000h 8   0 2 5778 R 8  4896h 7 R 7  72000h 2  6 R 6  434688h 35 R 5  2643456h 4 4 R 4  9953280h 5 3 R 3  28262400h 6 2 R 2  49152000h 7 R  40960000h8 p9 1 0

The nodal stresses can be obtained by substituting the values of the pressures into the equation

r  0  p The exact solution, as provided by P. C. Sharma (2003), is given as: 2   R r    x   0 1  e h   

Example 2: Consider the axi-symmetric forging of a circular disc of diameter 28mm and thickness 10mm with a coefficient of friction,   0.20 . Assume that no sticking occurs. The pressures at the nodes as solved by both the weighted residual finite element method and the exact method are as shown in table 2 below: Table 2: Comparison of finite element solution and exact solution for an axisymmetric forging operation. x (mm)

Finite element solutions Pressure (p)

Exact solutions Pressure (p) 6.467

Stress(  ) (compressive) 5.467

0

6.308

Stress (  ) (compressive) 5.308

1.75

4.993

3.993

5.121

4.121

3.50

3.965

2.965

4.055

3.055

5.25

3.126

2.126

3.211

2.211

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2nd International Conference On Engineering Research & Development: 1559 Innovations (15th – 17th April 2008), Benin City, Nigeria 7.00

2.496

1.496

2.543

1.543

8.75

1.955

0.955

2.014

1.014

10.50

1.576

0.576

1.595

0.595

12.25

1.221

0.221

1.263

0.263

1.0000

0

1.000

0

7

6

Forging pressure (p)

5

4

3

2

1

0 -20

-15

-10

-5

0

5

10

15

20

Radial distance from center (r) Finite element solution

Exact solution

Figure 4: Graphical comparison of the friction hills of the exact solution and the finite element solution.

4. Discussion of results and Conclusions The solutions obtained in sections 2 and 3 can be applied to all open die forging problems, this advantage is as a result of the fact that numerical values of the pressures and stresses of such problems can be determined by simply substituting the appropriate values of the coefficient of friction, height of forging and half the length of the forging into the three-parameter solutions provided. Furthermore, a careful examination of figures 2 and 4 show that the differences between the friction hills described by the exact solutions and the finite element solutions is insignificant and negligible. It can therefore be

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2nd International Conference On Engineering Research & Development: 1560 Innovations (15th – 17th April 2008), Benin City, Nigeria concluded that the weighted residual finite element method is capable of adequately and accurately predicting the stresses and pressure fields set up in a particular forging process.

References J. Navarrete, M. E. Noguez, J. Ramirez, G. Salaz and T. Robert, 2001, Die Forging Stress Determination: A Dimensional Analysis Approach, Journal of Manufacturing Science and Engineering, Vol. 123, Issue 3, pp. 416-419. T. J. Nye, A. M. Elbadan and G. M. Bone, 2001, Real-Time Process Characterization of Open Die Forging for Adaptive Control, Journal of Engineering Materials and Technology, Vol. 123, Issue 4, pp. 511-516. A. Alfozan and J. S. Gunasekera, 2003, An Upper Bound Element Technique Approach to the Process Design of Axisymmetric Forging by Forward and Backward Simulation, Journal of Materials Processing Technology, Vol. 142, pp. 619-627. P. C. Sharma, 2003, A Textbook of Production Engineering, 4th edition, S. Chand & Company LTD., New Delhi, Chapter 13: Analysis of Metal Forming Processes, pp. 444-451. Reddy J. N., 1984, An Introduction to the Finite Element Method, Texas, McGraw-Hill, second edition. D. S. Burnett, 1987, Finite Element Analysis, from Concept to Application, New Jersey, Addison Wesley W. B. Bickford, 1989, A First Course in the Finite Element Method, PWS Publishing Company. M. J. Fagan, 1992, Finite Element Analysis, Theory and Practice, Essex, England, Longman Scientific and Technical. J. Raftoyiannis & C. C. Spyrakos, 1997, Linear and Nonlinear Finite Element Analysis in Engineering Practice, Includes Examples with ALGOR, Pittsburgh, Algor incorporated publishing division. C. C. Spyrakos, 1996, Finite Element Modeling in Engineering Practice, Includes Examples with ALGOR, Pittsburgh, Algor incorporated publishing division.

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2nd International Conference On Engineering Research & Development: 1561 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08154) Pressure Derivative Studies of a Laterally Infinite Reservoir with a Horizontal Well Ovwigho, K.1 and Adewole, E.S.2 (1,2) Petroleum Engineering Department, University of Benin, Nigeria (2) [email protected] Abstract Dimensionless pressure derivatives of a laterally infinite reservoir drained with a horizontal well are studied. The effect of anisotropy on the derivative response is also studied. It is revealed that anisotropy mainly affects the start of the late radial flow regime, and for cases where LD is small ( 1.0. For k2/k1 > 1.0, the high rise in the dimensionless pressure distribution indicates a huge fluid pressure on the producing layer of current completion may be due to a higher propensity for the reservoir fluids to flow across the interface to the layer of lower permeability of k1. A long transition period is observed before the brand new layer experiences depletion and this fully occurs when the first layer is almost depleted. It is also seen that the transient is being felt at much later time for cases of á greater than unity. The pressure derivative for á equal to ten reveals the same stabilization value of 0.5 similar to the revelation by Bourdet et al[4]. Interpretation Based on Decreasing values of á The type curves progressively shift to the right with low peaks of dimensionless pressure distribution and derivative values. The shifts further and further to the right show that the system is layered with increasing degree of heterogeneity between the layers involved and in terms of well completion, the well was completed in the layer of higher permeability. It therefore signifies that the current completion is good and work over operations is not a critical issue at that moment as they can be done much later to increase the permeability and enhance depletion of the brand new layer at much earlier time. Even when the hump is not visible for both pressure distribution and derivatives, for the fact that the transient begins to be noticeable at much later times is a signal that the reservoir is a layered system. The derivatives for a good completion are always below the pressure distributions. Interpretation Based on increasing values of á If k2 >k1, there is a huge hump observed signifying a high dimensionless pressure response. This indicates that a lot of fluid overburden from the higher permeability layer tends to cross the interface into the layer of lower permeability layer, where the well was completed. The pressure transient is largely felt by the current layer at much earlier times. This is logical and expected due to the high pressure buildup from the adjoining layer of high pressure fluids tending to force its way across the interface. There is a huge time delay before the brand new layer of higher permeability is felt. However, during this time delay, there will still be cross flow to some degree across the interface as fluids will want to replace the produced hydrocarbons volume for volume in layer two almost instantaneously. The huge pressure hump and derivative curves show that the current completion is not intelligently done as it is not in the layer of higher permeability and hence urgent steps must be taken such as recompleting the well. The merging of both pressure distribution and derivative curves shows that for a bad completion, the derivative gives a higher hump value compared to the distribution. This is a signal that current completion was not intelligently done and recompletion is absolutely necessary.

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2nd International Conference On Engineering Research & Development: 1575 Innovations (15th – 17th April 2008), Benin City, Nigeria

Fig.2: Type curves generated from Dimensionless Pressure and Pressure Derivative Expressions Conclusion The major conclusions from this study are (1) No matter were the vertical well is completed, increasing values of á shows that the current completion of the well was done in the lower permeable layer of the reservoir and its pressure transient response is highly felt by the current layer at very early times followed by a long transition period before the layer of higher permeability experiences full depletion. There is thus a shift in of the pressure transient to the left. This necessitates recompleting the well if higher production rates must be achieved. (2) For decreasing values of á, the well may have been completed in the layer of higher permeability and there is a shift of the pressure transient to the right of the pressure distribution and derivative curves for the current layer followed by a short transition period. (3) At the interface, there is a humplike deviation from the normal pressure distribution response curve for a layered system. In the absence of layering, this hump is not visible. (4) The hump in the layer of completion is enormous for both pressure distribution and pressure derivative. (5) For largely heterogeneous layers, there is a long transition period between the end of depletion of layer one (first layer) and the beginning of depletion of the second layer. (6) For the pressure derivative response, the curve eventually stabilizes at a pressure derivative dimensionless value of 0.5 indicating infinite radial flow regime.

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2nd International Conference On Engineering Research & Development: 1576 Innovations (15th – 17th April 2008), Benin City, Nigeria Nomenclature j layer number k average permeability, md pD dimensionless pressure rD dimensionless radius rwD dimensionless well radius yD= dimensionless y-direction zD dimensionless z-direction  dimensionless dummy time variable References 12. Bourdet,D., Whittle,T.M., Douglas, A.A., and Pirard, Y-M.: “A New Set of Type Curves Simplifies Well Test Analysis,” World Oil, (May 1983), 95 – 106. 13. Bourdet, D., Ayoub, J.A., and Pirard, Y-M.: “Use of the Pressure Derivative in Well Test Interpretation,” SPE Formation Evaluation, (June 1989), 293 – 302. 14. Onur, M., Yeh, N.S. and Reynolds, A.C.: “New Applications of the Pressure Derivative in Well Test Analysis,” SPE Formation Evaluation, (Sept. 1989), 429 – 437. 15. Tiab, D. and Kumar, A.: “Application of the pD’ Function to Interference Analysis,” J.P.T. (Aug. 1980), 1465 – 70. 16. Proano, E.A. and Lilley, I.J.: “Determination of Pressure: Application to Bounded Reservoir Interpretation,” paper SPE 15861 presented at the SPE European Petroleum Conference, London, October 20-22, 1986. 17. Osman, M.E.: “Transient Pressure Analysis for Wells in a Mutilayered Reservoir with Finite Conductivity Fractures,” paper SPE 25665, presented at the Middle East Oil Technical Conference and Exhibition, Bahrain, April 3-6, 1993. 18. Al-Ajimi, N.M., Kazemi, H. and Ozkan, E.: “Estimation of Storativity Ratio in a Layered Reservoir with Crossflow,” paper SPE 84294 presented at the Annual Technical Conference and Exhibition in Denver, Colorado, October 5-8, 2003.

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2nd International Conference On Engineering Research & Development: 1577 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08188) The Influence of Vibration Time and Sand Type on the Compressive Strength of Sandcrete Hollow Blocks. O.E Alutu ENIStructE(1). and A. Omorogie(2) (1,2)

Civil Engineering Department University of Benin, Benin City; (a)Phone No: 08055860042; (a) E-Mail: [email protected]

Abstract: The purpose of this study is to see if varying the vibration time and sand type during moulding of blocks would affect the strength of the blocks. To this end, seven types of sands: Okuahia and Ovia river sands; Okuahia, Ovia, Ikpoba flood and Okhoro erosion sands were collected for the study. A total of 315 blocks each in 150mm and 225mm sizes with cement to sand ratios of 1:6 were made using the seven brands of sand. The blocks were vibrated for 10, 15, 20, 25, and 30 seconds and tested for compressive strength at 7 days, 14 days and 28 days respectively. The result showed that the relationship between compressive strength of the blocks and the vibration time for various sand types was linear up to vibration time of 30 secs. The sand type also influenced the strength of the blocks as Okuahia river sand gave the highest compressive strength followed by Ovia river sand and the least was Okhoro erosion sand. At least 52% increase in compressive strength of 150mm and 225mm sandcrete blocks were achieved by raising the vibration time from 15 seconds to 25 seconds in the seven types of sand and 100% increase is achieved by raising the vibration time from 15 to 30 seconds. Keywords: Sands, vibration time, improvement, strength, blocks. Introduction In Benin City, there are different types of sand which are found in large quantities either dredged from river or occurring naturally as underground deposits. These are quarried and used for construction purposes especially in making of sandcrete blocks. Of all these, according to Omoregie and Alutu(1) the most poorly graded fine aggregates is the most widely used because they are readily available and cheap. The current widespread use of poorly graded fine aggregates (low-price fine aggregates) in Benin City is a worrisome phenomenon in view of the inadequate knowledge of their properties and the implication of their present usage in block making. This is perhaps the remote cause of the low strength of commercially produced blocks in Benin City. In a state-of-the-art survey carried out in Southern Nigeria by Alutu(2), it was found that the cement/sand and water/cement ratios used in making commercially produced blocks were between 1:10 and 1:16 and 0.7 and 1.0. These are contrary to the cement/sand and water/cement ratios of 1:6 and 0.6 recommended by the Nigerian industrial standards (NIS)(3) for sandcrete blocks production in Nigeria. From the studies carried out by Akagu and Okolie(4), Florek(5), Alutu and Asein(6) on sandcrete blocks in the Eastern States, Northern States and the whole of the southern Nigeria respectively, it was shown that all the blocks tested in these studies were substandard, and of low compressive strength. Thus, the blocks produced commercially by block moulding industries in Nigeria do not meet the standard specification of 2.1 N/mm2 compressive strength specified by Federal Ministry of Works and Hosing (FMWH)(7) and the Nigeria Industrial Standards (NIS)(3). Furthermore, the vibration time used in compacting these blocks is found to be between 10 seconds and 18 seconds. This is inadequate resulting in low density and strength(2). Usually, for the sandcrete blocks to have good properties and strength their cement content should be about 15% and vibration time should be between 20 to 30 seconds. This has been found not to be so. Indeed, the commercially produce blocks in Nigeria have cement content between 6% and 9%(8). Despite the fact that these blocks are of low compressive strength, yet they are not cheap. There is therefore need to improve upon the strength and characteristics of blocks produced commercially in Nigeria by block moulding industries, and where possible, without having to increase the cement content. As a step towards the enhancement of the strength of sandcrete blocks produce commercially, Omorogie and Alutu(1) had used a combinational approach. They have used some percentage of well-graded pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1578 Innovations (15th – 17th April 2008), Benin City, Nigeria fine aggregates to blend the poorly graded ones and found that the grading parameters of the blend improved tremendously with the compressive strength of ;the sandcrete blocks made with the blended sand increasing by up to 103% in some cases. They showed that for a minimum production cost increment of 8% to 11%, a very high compressive strength of 99% to 103% could be achieved. There is therefore the need to search further for ways to improve on the compressive strength of sandcrete blocks. As earlier, the vibration time during compaction of blocks of 15 secs on the average used in the blocks industries at present is definitely inadequate for production of strong and dense blocks. The purpose of this study is to see if varying the vibration time from 10 to 30 seconds during the compaction of blocks in the mould would affect the strength of the blocks significantly. It also seeks to determine satisfactory value of the vibration time needed for economic production of the blocks. The contribution to strength gain by sand type will also be investigated. Methodology The following methods were adopted in the preparation of the materials and the moulding and testing of the blocks: Sampling of the fine aggregates The method adopted for sampling the fine aggregates is the riffler method as described in BS 812: Part 1.(9); Naville(10). Each sand sample is discharged into the riffler over its full width, and the two halves are collected in two boxes at the bottom of the chute of each side, one half is discarded and the riffling of the other half is repeated until the sample is reduced to the desired size. The samples were spread in the laboratory to ensure they were dry before being used. Sieve Analysis The sieve analysis was carried out by shaking the sample through a stack of wire screens with openings of known sizes in accordance with BS 812: Part 1(9): 1975, and as described in Naville and Brooks(11). The sample of the sand required (about 100gm) was weighed and oven dried for twenty-four hours at 110oC. The sieves were arranged in order of decreasing diameter and a pan was placed after the smallest sieve. The sand was sieved through the rest of the sieves by a mechanical shaker. This process was repeated for the various sands. The percentage passing each sieve was determined to enable the grading curve to be plotted. Moulding of Blocks A block moulding machine was used for this purpose. This machine effects compaction by vibration combined with compaction. The vibration was timed for five sets of blocks: 10 seconds, 15 seconds, 20 seconds, 25 seconds and 30 seconds before compaction. For each of the five periods, sandcrete blocks comprising of 315 blocks for 225mm and 315 blocks for 150mm blocks were produced. A total of 630 blocks samples were moulded. Demoulding of the blocks was archived by means of a guided mechanical device. The moulding of freshly made blocks was carefully done in order to avoid distortion and edge breaking. Freshly made blocks were carried in pallet racks to location where they were temporarily kept before curing commenced. The sandcrete blocks were produced under very controlled conditions. The mix ratio adopted was cement-to-sand ratio of 1:6. The water/cement ratio of 0.8 was used and the water added was the difference between the optimum moisture content of the sand earlier determined and the actual moisture content of the sand. All batching was carried out by weight. Curing: After the setting, the blocks were kept moist by wetting until sufficient strength was gained. The freshly made blocks were place under a covered place to avoid the hot, dry weather and possible heavy rain. Sprinkling of water, morning and evening, was carried out until 28 days when sufficient strength was expected to have been gained. When the specimen was sufficiently dried, compressive strength was tested. Compressive Strength Test The compressive strength test was carried out on the blocks to BS 6073: Part 2.(12) after 7, 14 and 28 days curing. The test method employed was the use of the electro-hydraulic machine of capacity 2500 KN. A pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1579 Innovations (15th – 17th April 2008), Benin City, Nigeria total of 630 blocks samples (150mm and 225mm) at 3 blocks at 7 days and 28 days crushing periods were tested respectively for the seven types of sands under investigation and for 10, 15, 20, 25 and 30 seconds vibration times. Results: The result of the compressive strength test for various sand types subjected to 10,15,20, and 25 seconds vibration are given in Table 1 for 225mm sandcrete blocks. The result of compressive strength test for 150mm for various sand types and 10,15,20,25 and 30 seconds vibration time are given in Table 2. The gain in strength of 225mm and 150mm sandcrete blocks arising from the raising of vibration time from 15 to 25 seconds is shown in Table 3. The gain in strength of 225mm and 150mm sandcrete blocks arising from the raising of vibration time from 15 seconds to 30 seconds is also shown in Table 4. The graphs of compressive strength of 150mm sandcrete blocks for various sand types against vibration time is given in Fig. 1 while that of 255mm blocks is shown in Fig. 2. Graph of compressive strength of 150mm blocks against sand types for 25 seconds vibration time are shown in Fig. 4. while that of 225mm blocks are given in Fig. 5. The particle sizes distribution curves for the various sand types are shown in Fig 3.

Table 1 – Compressive strength of 255mm sandcrete blocks for various sand types for 10, 15, 20, 25 and 30 seconds vibration times. Vibration time 10 seconds 15 seconds 20 seconds 25 seconds 30 seconds Sand Type 7 14 28 7 14 28 7 14 28 7 14 28 7 14 28 da da da da da da da da da da da da da da da ys ys ys ys ys ys ys ys ys ys ys ys ys ys ys Okohro flood sand 0.6 0.8 1.1 0.9 1.2 1.6 1.2 1.6 2.0 1.5 2.0 2.4 1.9 2.4 2.9 (OES) 4 4 5 2 3 0 2 7 0 2 5 Ikpoba Erosion sand 1.0 1.1 1.5 1.4 1.4 1.7 1.5 1.7 2.0 1.7 2.0 2.5 2.0 2.3 2.7 (IES) 6 4 2 8 5 0 9 9 7 2 1 0 Granite dust (GD) 1.2 1.2 1.3 1.8 1.9 1.8 2.3 2.4 2.4 2.9 3.0 3.0 3.4 3.5 3.6 3 7 0 5 3 4 7 0 5 5 5 Ovia Erosion sand 1.3 1.7 1.9 1.9 2.8 3.0 2.5 3.9 4.0 3.1 4.8 5.0 3.8 5.9 6.0 (OVES) 2 5 4 0 5 0 1 8 8 2 0 0 4 Okuahia Erosion sand 1.3 1.4 1.4 2.0 2.7 2.7 2.7 3.9 3.9 3.3 5.1 5.2 4.0 6.3 6.5 (OKES) 6 4 9 0 1 0 3 6 4 4 8 5 2 Ovia River sand 1.3 1.4 1.5 2.0 2.8 2.8 2.8 4.0 4.1 3.5 5.3 5.5 4.2 6.6 6.8 (OVRS) 0 7 6 5 5 6 6 9 3 2 0 0 Okuahia River sand 1.3 2.2 2.3 2.1 3.3 3.4 2.8 4.3 4.5 3.6 5.5 5.5 4.4 6.6 6.8 (OKRS) 8 2 6 0 5 7 3 4 3 9 0 2 2

Table 2 – Compressive strength of 150mm sandcrete blocks made with various sand types for 10, 15, 20, 25 and 30 seconds vibration times Vibration Time (Secs) Sand

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2nd International Conference On Engineering Research & Development: 1580 Innovations (15th – 17th April 2008), Benin City, Nigeria Type

OES IFS GD OVES OKES OVRS OKRS

10 secs 7 14 28 days days days

15 secs 7 14 28 days days days

20 secs 7 14 28 days days days

25 secs 7 14 28 days days days

7 days

30 secs 14 28 days days

0.65 0.67 0.88 1.34 1.28 1.41 1.51

0.96 1.00 1.30 2.0 1.9 2.15 2.30

1.3 1.39 1.74 2.68 2.56 2.9 3.02

1.66 1.73 2.18 3.38 3.23 3.6 3.75

2.02 2.10 2.65 4.03 3.90 4.35 4.50

2.22 2.25 3.10 4.50 4.39 4.75 5.044

0.74 0.8 1.20 1.51 1.43 1.61 1.7

0.91 0.94 1.19 1.85 1.78 2.04 2.05

1.1 1.2 1.65 2.25 2.20 2.40 2.55

1.36 1.40 1.80 2.75 2.65 3.0 3.05

1.47 1.58 2.11 2.99 2.88 3.17 3.4

1.81 1.87 2.38 3.67 3.55 4.03 4.1

1.86 1.94 2.6 3.78 3.61 4.01 4.2

2.26 2.35 2.98 4.58 4.44 5.04 5.11

Table 3: 28days Gain in strength of 225mm and150mm hollow blocks arising from raising vibration time from 15 to 25 seconds. Types of sand

Gain in strength of 225 blocks N/mm2 0.87(54%) 0.92(52%) 1.25(69%) 2.0%(67%) 2.57(95%) 2.68(94%) 2.19(65%)

OES IFS GD OVES OKES OVRS OKRS

Gain in strength of 150mm blocks N/mm2 0.9(66%) 0.95(68%) 1.18(66%) 1.83(67%) 1.79(68%) 2.04(68%) 2.06(68%)

Table 4: 28days Gain in strength of 225mm and 150mm hollow blocks arising from raising vibration time from 15-30 seconds Types of sand

OES IFS GD OVES OKES OVRS OKRS

Gain in strength of 225mm hollow blocks N/mm2

1.35 (100%) 1.42 (101%) 1.80 (100%) 3.05 (1401%) 3.81 (141%) 3.95 (139%) 3.42 (101%)

Gain in strength of 150mm hallow blocks N/mm2 1.36 (100%) 1.42 (100%) 1.77 (100%) 2.75(100%) 2.65 (100%) 3.0 (100%) 3.05 (100%)

Compressive strength N/mm2

6 5 4 3 2 1 0 10 secs

15 secs

20 secs

25 secs

30 secs

Vibration time in secs Fig. 1. Graphs of compre ssive strength of 150mm sandcre te blocks made with various local sand types against vibration time

7 days (OES) 14 days (OES) 28 days (OES) 7 days (IFS) 14 days (IFS) 28 days (IFS) 7 days (GD) 14 days (GD) 28 days (GD) 7 days (OVES) 14 days (OVES) 28 days (OVES) 7 days (OKES) 14 days (OKES) 28 days (OKES) 7 days (OVRS) days (OVRS) 28 days PDF (OVRS)files with ease! pdfMachine - is a pdf writer14that produces quality 7 days (OKRS) 14 days (OKRS) 28 days (OKRS)

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2.27 2.82 3.60 5.50 5.30 6.00 6.10

Compressive strength N/mm2

2nd International Conference On Engineering Research & Development: 1581 Innovations (15th – 17th April 2008), Benin City, Nigeria

8 7 6 5 4 3 2 1 0 10 secs

15 secs

20 secs

25 secs

30 secs

Vibration time (se cs ). Fig. 2. Graphs of compre s s ive s tre ngth of 225mm s andcre te blocks made with various local s ands against vibration time . 7 d ay s 7 d ay s 7 d ay s 7 d ay s 7 d ay s 7 d ay s 7 d ay s

(OES) (IFS) (GD) (OVES) (OKES) (OVRS) (OKRS)

14 d ay s 14 d ay s 14 d ay s 14 d ay s 14 d ay s 14 d ay s 14 d ay s

(OES) (IFS) (GD) (OVES) (OKES) (OVRS) (OKRS)

28 days 28 days 28 days 28 days 28 days 28 days 28 days

(OES) (IFS) (GD) (OVES) (OKES) (OVRS) (OKRS)

120

Percentage Passing (%)

100 80 60 40 20 0 0.01

0.1

1

10

100

Particle Size (mm) Fig. 3: Particle Size Distribution Curve For the Local Sands

OES

IES

GD

OVES

OKES

OVRS

OKRS

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2nd International Conference On Engineering Research & Development: 1582 Innovations (15th – 17th April 2008), Benin City, Nigeria From Figs 1 and 2, it can be seen that the graphs of compressive strength of sandcrete blocks made with various sand samples against vibration time are linear up to the vibration time 30 seconds considered in this study. Thus, over this range, the more the vibration the more the strength gain. However, the graph is not expected to continue to be linear well beyond 30 secs vibration time but becomes asymptotic to a particular compressive strength which will be parallel to the vibration time axis well beyond 30 seconds vibration time if a full range of vibration time is considered. The determining this asymptotic point is outside the scope of this study. A survey carried out in southern Nigeria by Alutu(2) revealed that 70% of block manufacturing industries studied compact their blocks for vibration time which is below 15 seconds and 30% vibrate their blocks between 15 and 18 seconds. This means that the average vibration time used by block manufacturing industries in southern Nigeria is about 15 seconds. This yields blocks that are of low density and strength. From Table 3, it can be seen that 52-95% increase in compressive strength of 225mm sandcrete blocks can be achieved by increasing the vibration time of the blocks from 15 seconds to 25 seconds; while 66-68% increase in strength can be achieved for 150mm blocks depending on the type of sand used. For most commonly used sand with the exception of Okhoro and Ikpoba erosion sands (poorly graded sands), at least 65% increase in strength can be achieved by raising vibration time from 15 to 25 secs. The additional fuel cost for additional vibration time of 10 seconds is virtually insignificant compared with a gain in strength of 65%. Ideally, all blocks should be vibrated for at least 25 seconds to take advantage of the 65% increase in strength. From Table 4, it can be seen that between 100% increase in compressive strength of 225mm and 150mm sandcrete hollow blocks can be achieved by increasing the vibration time of the blocks from 15 to 30 seconds. The addition fuel cost for the additional vibration time of 15 seconds is again very insignificant compared to gain in strength of up to 100%. From Figs. 4 and 5, it can be seen that the strength gain by the blocks depended also on the type of sand used. Okhuahia River sand (OKRS) gave the highest compressive strength after 7, 14 and 28 days curing. This was followed by Ovia River sand (OVRS), Okhuahia Erosion sand (OKES) and Ovia Erosion sand (OVES). Others, such as granite dust (GD), Ikpoba flood sand and Okhoro erosion sand (OES) have much lower compressive strengths. Okhoro erosion sand gave the least compressive strength. From the Sieve Analysis result (Fig. 3) granite dust was the coarsest fine aggregate among the seven sand types and the one that seem to have minimum silt content among the others, yet the granite-dust blocks had low compressive strength. This poor performance of granite dust in block production can be attributed to the presence of mica in it. Mica is a shinning powdery substance that links one of its particles to another in chains under the influence of any mechanical vibration or contact with water. Due to its weight, gravitational pull makes mica practically impossible to be taken for silt. Mica chain linkage of one particle to another creates shears in the sandcrete blocks. This shear created by mica was responsible for the poor performance of granite dust as block making fine aggregate.

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compressive strength in N/mm2

2nd International Conference On Engineering Research & Development: 1583 Innovations (15th – 17th April 2008), Benin City, Nigeria 6 4 2 0 OES

IFS

GD

OVES

OKES

OVRS

OKRS

S and type Fig. 4: Graph of com pre s sive s tre ngth of 150 s andcre te block s again st variou s local san d type s for 25 s e cs vibration tim e . 7 d ay s

14 d ay s

28 d ay s

6

Compressive strength (N/mm2 )

5 4 3 2 1 0 OES

IFS

GD

OVES

OKES

OVRS

OKRS

S and type. Fig. 5. Graph of compressive strength of 225mm sandcrete blocks against various local sand types for 25 secs vibration time.

7 days

14 days

28 days

Recommendations From the results of this study the following recommendations are made: 1) Okhoro erosion sand and Ikpoba flood erosion sand (poorly graded) should be blended using Okhuahia or Ovia river sand for best performance(1). 2) Vibration time of blocks made in Nigeria should be between 25 and 30 seconds. This will enhance the strength of blocks by at least 65% for most sands. 3) Okhuahia erosion and Ovia erosion and river sands are recommended for block making on their own merit without blending(1). Conclusions From the findings of this study the following conclusions can be drawn: i) Compressive strength of blocks is directly related to its vibration time for vibration time upto 30seconds. ii) Vibration time of 15 seconds in use in the block industries at present is inadequate. iii) 2-95% increase in compressive strength of 225mm sandcrete blocks can be achieved by raising the vibration time from 15 to 25 seconds.

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2nd International Conference On Engineering Research & Development: 1584 Innovations (15th – 17th April 2008), Benin City, Nigeria iv)

v) vi) vii) viii) ix)

At least 65% increase in compressive strength of sandcrete blocks (150 or 225mm) can be achieved by raising vibration time from 15 to 25 seconds with the exception of Okhoro and Ikpoba erosion sands. 100% strength enhancement could be achieved by vibrating all blocks up to 30 seconds. Blocks made with Okhuahia river sand gave the highest compressive strength at 7, 14 and 28 days. Blocks made with Okhoro erosion sand gave the lowest compressive strength. Blocks made with granite dust gave low strength due to the presence of mica flex in granite dust. Sand type did affect the strength of the blocks in that the finer the sands the more water/cement ratios and hence the lower the strength of blocks.

References (1)

O.E Alutu and A. Omorogie “The influence of fine aggregate combinations on particle size distribution, grading parameters on compressive strength of sandcrete blocks”. Canadian Journal of Civil Engineering. Vol 33 No. 10. 2006.

(2)

O.E Alutu “The state-of-the-art of sandcrete block industries in Southern Nigeria”. Knowledge Review. 11 (1) 2005 pp. 50-57.

(3)

Nigerian Institution Standard (NIS). “Draft code of practices for sandcrete blocks Federal Ministry of Industries”, Lagos. 1972.

(4)

C. Akakgu and K. Okolie “Quality control in building delivery process”. Nigeria Institute of Architects. Vol. 3 Enugu State. 1995.

(5)

A.J. Florek “Quality of sandcrete hollow blocks manufactured in Nigeria”. Proceedings of the 17th annual conferece on material control and research, Lagos.

(6)

O.E. and M.F. Asein, Strength and Density of Ready-made sandcrete blocks produced in Nigeria: Implication for design of masonry walls. Nigeria Academic Forum Vol. 10. No.1 pp. 26-33, 2006.

(7)

Federal Ministry of Works and Housing ‘Item. 61’-Review Committees Comments. Federal Ministry of Works Proceedings of annual Conference, Oct. 1979, Kano.

(8)

O.E Alutu and A.E Oghenejobo “Strength, durability and effectiveness of cement-stabilized laterite hollow blocks”. Quarterly Journal of Engineering Geology and Hydrogeology 39,6572 UK. 2006.

(9)

British Standard Institution BS812: Part 1: Sampling, shape, size and classification. London. 1975 BSI

10)

A.M. Naville “Properties of concrete”. Forth Edition. ELBS/Longman. Singapore. 1988.

(11)

A.M. Naville and J.J. Brooks “Concrete Technology”. ELBS Edition. Longmans Singapore Publishers (Pte) Ltd. 1994.

(12)

British Standard Institution BS 6073: Part 2: “Method of specifying precast masonry Unit” BSI. London 1981.

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2nd International Conference On Engineering Research & Development: 1585 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08187) The Quality of Concrete made with Typical Benin City Silty Sand. O.E Alutu FNIStructE(1)a). and E. N. Ejike, FNIStruct(2) (1,2)

Civil Engineering Department University of Benin, Benin City; (a)Phone No: 08055860042; (a) E-Mail: [email protected]

Abstract The purpose of this study is to carry out tests on concrete made with a typical Benin City silty sand and determine the major concrete quality indicators such as pulse velocity, water/cement ratio and compressive strength in order to justify the continued utilization of such sands in concrete production in and around Benin City. To do this, concrete made with the selected sand were designed using DOE mix design method and test cubes were cast in three batches. Two cubes were cast for each of the sixteen consecutive tests carried out and averages taken for each design grade strength of 10,20,30,40 and 50N/mm2. Also, pulse velocity and rebound hammer tests were carried out on the cubes before testing the cubes destructively. The results show that concrete produced with the Benin City silty sands are of good quality in all respect but generally characterized by low 28th day – characteristic strength. The sands should therefore be used in construction provided that the mean strength aimed at during design is sufficiently higher than the characteristic strength from structural point of view to enable every part of the structure have adequate strength. Key words: Sand, Utilization concrete, quality. INTRODUCTION: The principle behind the ultrasonic pulse velocity test is that the velocity of sound in a solid material, V, is a function of the square root of the product of acceleration due to gravity, g, and the ratio of its modulus of elasticity, E, to its density,  . This relationship can be used for the determination of the modulus of elasticity of concrete if the poison’s ratio is known and hence a means of checking the quality of concrete. Whitehurst(1) classified concrete interms of quality on basis of pulse velocity test on the concrete. He specified that concrete with longitudinal pulse velocity greater than 4.5, between 3.5 and 4.5, between 3.0 and 3.5, between 2.0 and 3.0 and less than 2.0km/sec can be adjudged as excellent, good, doubtful, poor and very poor respectively. Jones and Gatfield(2), however set the lower limit for good quality concrete as between 4.10 and 4.7km/sec pulse velocity value. Pulse velocity test can easily detect lack of compaction and change in water-cement ratio, in concrete. However, the pulse velocity can not be used as a general quality indicator of compressive strength because the type of coarse aggregate and its content in concrete greatly influence the relation between pulse velocity and strength(3). Thus compressive strength will have to be determined by other methods. Concrete is a variable quantity and the sources of variability are many: variations in mix ingredients, changes in concrete making and

placing, and also, with respect to test results, the variations in the sampling procedure and testing. It is important to minimize this variability by quality control measures. Since strength is a variable

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2nd International Conference On Engineering Research & Development: 1586 Innovations (15th – 17th April 2008), Benin City, Nigeria quantity, a mean strength higher than the minimum required from structural standpoint is targeted when designing concrete mix so that every part of the structure will be expected to be made of concrete of adequate strength. This mean strength, fm, is given as the sum of the minimum required or characteristic strength, fmin and a margin equal to the product of the probability factor, k, and the standard deviations, of cube test results. Thus when the probability factor, k is chosen as 1.64, it means that there is a probability that 1 in 20 or 5% of the strength values will fall below the minimum strength. According to BS5328(4), acceptance and compliance with the characteristic strength is based on groups of consecutive test results, as well as single test results. Each result is the average of at least two cubes, made in the specified manner from concrete which is sampled at a prescribed rate and normally tested at 28 days. According to BS5328: Part 4.(4), compliance requirement for compressive strength is achieved if the minimum value by which the mean strength of the group of test results should exceed the grade strength is 2N/mm2. This is determined from first three consecutive test results for characteristic strength greater than 20N/mm2. For characteristic strength less than 20N/mm2 the value is 1N/mm2. In addition, the maximum value by which any individual test result falls short of the grade strength should be 3N/mm2 for characteristic strength greater than 20N/mm2 and 2N/mm2 when less. Since most of the properties of concrete improved with increasing strength and for this reason the quality of concrete is often judged by its strength. Thus, the option left is direct strength measurements involving destructive tests on cubes. Schmidt hammer test is also useful as a measure of uniformity and relative quality of concrete on a structure or in the manufacture of a number of similar precast members but not as an acceptance test. There is no unique relationship between hardness of concrete but experimental relations can be determined for a given concrete; the relationship is dependent upon factors affecting the concrete surface, such as degree of saturation and carbonation. In Benin City, there are different types of fine aggregates which are found in large quantities and used in construction either dredged from river or occurring naturally as underground deposits that are sometimes exposed to the surface(5). These are Okhoro erosion sand (OES), Ikpoba erosion sand (IES), Ovia erosion sand (OVES), Okhuahia erosion sand (OKES), Ikpoba river sand (IRS), Ovia River sand (OVRS) and Okhuahia river sand (OKRS). Okhoro, Ikpoba and Ovia river sands are sands in zone 3 whereas Okhuahia erosion, Ikpoba, Ovia and Okhuahia river sands are sands in zone 2.(5) The findings from a study by Omoregie and Alutu(6) has revealed that Okhoro, Ikpoba flood and Ovia erosion sands contain 2.39%, 2.26% and 1.63% silt respectively. Thus, the typical Benin City silty sand is any of Ikpoba, Ovia and Okhoro erosion sands. The sand used in this study is Ikpoba erosion sand. These sands are cheaper than river sands and therefore are preferred by private builders. British Standards BS882(7) defined sands in zone 3 as medium to fine sand with percentage passing sieve No. 25, or 600ìm equal to 60-79%. Omoregie and Alutu had concluded in their study of block strengths in Benin city that the sandcrete block failures and low strength of blocks are attributed to the sands with finer grading and higher silt content such as Okhoro, Ikpoba and Ovia erosion sands resulting in higher water/cement ratio requirement which reduces strength. This finding could also be applicable to concrete made with these silty sands. The purpose of this study is to carry out tests on concrete made with a typical Benin City silty sand (Ikpoba erosion sand) and measure the major quality indicators such as pulse velocity, water/cement ratio, compressive strength etc. in order to justify the continued utilization of such sands in concrete making in and around Benin City.

METHODOLOGY Sieve analysis: The method adopted for sieve analysis is the method described in BS812: Part 103:(8) and Neville and Brooks(9). This was carried out by mechanically screening the sand and weighing the sand retained on each sieve, expressing the weight retained as a percentage of the total sample. The aggregates were first sampled using the riffler method described in BS112:Part 1(10); (3) Neville and Jackson and Dhir(11) and subsequently spread in the laboratory to dry before being used. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1587 Innovations (15th – 17th April 2008), Benin City, Nigeria Cube tests on concrete: The method used for making test cubes was the one described in BS 1881: Part 108(12). Coarse and fine aggregate were batched under laboratory conditions using results of mix design computation (to DOE mix Design method). The required quantities of fine and coarse aggregates, water and cement were mixed thoroughly in the pan mixer. The compressive test cubes (150mm x 150mm x 150mm) were then cast and cured in water for the 28 days required before the test. Pulse velocity test on concrete cubes: Pulse velocity test on the concrete cubes was carried out to BS1881: Part 203(13). In this test, two electro-accoustical transducers were placed on the opposite faces of a concrete cube. The pulse produced by one of the transducers passing through the concrete is picked up by the other. The time taken by the pulse to travel through the concrete was measured by electrical timing unit to nearest 0.1ìs and the pulse velocity is calculated as u = L/t m/sec, where L is the length of the path (m) and t is time taken in secs. Schmidt hammer tests: Rebound hammer tests were carried out on concrete cubes to BS1881:Part 202(14). In this test, a spring-loaded mass had a fixed amount of energy imparted to it by extending a spring to a fixed position. This was achieved by pressing the plunger against the surface of the concrete under test. Upon release, the mass rebounded with the plunger still in contact with the concrete surface. The distance travelled by the mass expressed as a percentage of the initial extension of the spring called the rebound number was indicated by a rider moving along a graduated scale. This rebound number gave a measure of the hardness of the surface of the concrete cubes. Forty-eight readings over the area to be tested were taken and average found since the test is sensitive to the presence of aggregate and of voids immediately under heath the plunger. Compressive strength test: The method used for the compressive strength test was the one described in BS1881: Part 116(15). Twelve concrete cubes of the same trial proportion were cast for each of grades 10,20,30,40 and 50 for the age to be investigated. They were then tested using universal testing machine with load capacity of 1000KN and the average strengths noted. RESULTS The results of compressive strengths, pulse velocity, rebound hammer, slump, water-cement ratio; slump and density measurements are given in Table 1 for groups 1, 2 and 3 tests. Also the result of individual compressive strength for various grade strengths are given in Table 2. The average compressive strength, characteristic strength and standard deviation values from the three groups of tests for various grades of concrete are given in Table 3. A summary of constituent materials per m3 of the fresh concrete is given in Table 4. Particle size classification for the typical silty sand and the coarse aggregates used for the concrete are give in tables 5 sand 6 respectively. Table 1: Compressive strength, pulse velocity, rebound hammer, slump and density of concrete of various grades. Design cube strength N/mm2 Group 1 10 20

Density kg/m3

2577.78 2577.78

Slump (mm)

26 19

Mean pulse velocity (ìsec)

Actual pulse velocity km/s

41.15 36.75

3.645 4.082

Mean rebound number (No.) 11 12

Mean compressive N/mm2

8.15 19.70

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2nd International Conference On Engineering Research & Development: 1588 Innovations (15th – 17th April 2008), Benin City, Nigeria 30 40 50 Group 2 10 20 30 40 50 Group 3 10 20 30 40 50

2587.65 2857.65 2567.90

13 8 3

35.08 34.28 33.35

4.276 4.375 4.498

17 22 25

32.89 43.19 53.19

2553.69 2565.93 2554.07 2577.78 2596

27 22 16 11 5

38.83 35.45 34.94 34.57 33.27

3.88 4.23 4.29 4.32 4.51

11 14 17 22 26

9.6 21.2 30.09 40.89 48.8

2529.63 2548.15 2560.49 2559.26 255.55

27 21 15 12 3.0

36.51 35.69 34.88 34.30 32.57

4.11 4.20 4.30 4.37 4.60

11 13 18 23 25

11.0 21.19 30.6 41.39 47.36

Individual compressive strength values for sixteen consective tests on various standard design grade strengths. grade

Table 2: Table 3: Average compressive strength, characteristic compressive strength and deviation from the three groups of tests for strength of 10,20,30,40 and 50N/mm2. fm = fmin

+ks Individua l test marks Group 1 1. 2. 3. Group 2 1. 2. 3. 4. 5. Group 3 1. 2. 3. 4. 5. 6. 7. 8.

Grade strength of concrete (N/mm2) 10 20 30 40 50 8.22 8.13 8.08

20.0 19.55 19.55

32.0 33.33 33.33

42.44 42.67 44.44

50.22 56.44 52.88

10.00 10.15 9.40 12.0 10.67

20.89 20.44 20.89 21.78 22.0

30.00 30.67 29.78 29.78 30.22

41.56 40.22 40.00 41.33 41.33

49.33 49.33 49.00 50.67 50.67

11.77 12.18 10.71 9.33 10.67 12.0 10.67 10.67

20.0 20.22 22.22 22.22 23.33 20.31 20.00 22.0

33.33 29.78 32.88 30.22 29.33 31.55 32.00 30.22

42.22 40.89 40.00 40.44 42.22 43.78 42.67 38.88

42.22 48.88 43.22 46.44 48.88 50.44 48.22 50.00

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2nd International Conference On Engineering Research & Development: 1589 Innovations (15th – 17th April 2008), Benin City, Nigeria

Design Mean Standard strength (average of deviations N/mm2 16 results N/mm2 compressive strength fmN/mm2 10 10.3 1.37 20 20.96 1.41 30 30.96 1.36 40 41.57 1.46 50 49.2 3.3

Minimum compressive strength = fmin = fm-ks N/mm2 8.05 18.65 28.73 39.17 43.79

Summary of Quantities of constituent materials per m3 of fresh concrete.

Table 4: Mix design strength (N/mm2)

Free-water Cement content content kg/m3 kg/m3

10 20 30 40 50

190 190 190 190 170

225 380 455 530 550

Fine aggregate content kg/m3 630 515 475 435 425

Table 5: Particle Size Classification for the classification typical silty sand. Sieve size (mm) (ìm) 2.40mm 1.30mm 600 ìm 300 ìm 150 ìm 75 ìm

Weight Percentage Percentage retained retained passing % (gm) % 41.90 122.90 491.68 1135.89 619.27 73.01

1.68 4.92 19.67 45.44 24.77 2.92

98.32 93.40 73.73 28.29 3.52 0.60

Coarse aggregate content kg/m3 1365 1365 1320 1285 1315 Table 6:

Free water/cemen t ratio 0.74 0.50 0.42 0.36 0.31 Particle size

for the granite (coarse aggregate). Sieve Weight Percentage size retained retained % (mm) (gm) 19.05 629.70 12.59 13.20 2738.30 54.77 10.00 938.30 18.77 8.00 211.25 4.23 5.00 237.70 4.75 Maximum size = 19mm

Percentage passing % 87.41 32.64 13.87 9.64 4.89

Sample conforms to BS 882 Grading zone 3.

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2nd International Conference On Engineering Research & Development: 1590 Innovations (15th – 17th April 2008), Benin City, Nigeria DISCUSSIONS The results of the tests on fresh concrete and cured cubes are shown in Tables 1- 4. Normal aggregates are suitable for most purposes and produce concrete with density in the range 2300 to 2500kg/m3. The aggregates used in the tests can therefore be considered normal, producing concrete of mean density of 2577kg/m3. From Tables 1, it can be seen that the pulse velocity measured in the whole tests lie between 3.645 and 4.57km/sec. This agrees with Whitehurst’s classification of quality concrete on the basis of pulse velocity tests. This classification which stipulates that concrete with pulse velocity between 3.5 and 4.5 km/sec is considered to be in good quality class. However, Jones and Gatfield(2) set the limit for good quality concrete as one having pulse velocity between 4.1 and 4.7km/sec. Only the results of pulse velocity test on grade 10 concrete did not conform to this. Pulse velocity tests on other grades conformed to this. The other concrete quality indicator is the characteristic strength. According to BS8110(16) characteristic strength, fcu is that strength below which not more that 5% of the test results must fall i.e., the probability that 1 in 20 of the strength values of the tests will fall below the minimum strength. From Table 3, it can be seen that all the calculated minimum strengths or the characteristic strengths for the five grade strengths used in this study fell below the design strength. It was expected that the values of fmin of 8.05,18.65, 28.73, 39.17 and 43.79N/mm2 should be higher than 10, 20, 30, 40 and 50N/mm2 respectively. This result corroborates with the study by Alutu and Ifejika(5) that Ikpoba, Ovia and Okhoro erosion sands which are sands in zone 3 with fine to medium sized particles, higher silt content and lower strength. The result also agrees with the study by Alutu and Omoregie (2006) that the low strength of blocks, and failure of blocks during transportation of the blocks to sites are attributed to sands with fine to medium particles and higher silt content such as found in Ikpoba, Ovia and Okhoro erosion sands. These sands are finer and hence demand more water resulting in the lowering of compressive strength of concrete or block. According to BS5328: Part 4(4) compliance requirements for compressive strength is achieved if the minimum value by which the mean strength of the test results should exceed the design grade strength is 2N/mm2. This is determined from the first two, three, or four consecutive test results when characteristic strength is greater than 20N/mm2 and 1N/mm2 when characteristic strength less than 20N/mm2. From Table 2, it is clear that there is no first three consecutive test results that exceeded the characteristic strengths by 2N/mm2. Therefore, the compliance for compressive strength is not achieved, except in group 1 tests results where the first three consecutive test results exceeded the design grade strengths of 30 and 40N/mm2 by up to 2N/mm2. In addition, for the strength compliance and acceptance requirement to be achieved, the maximum value by which any individual test results will fall short of the design grade strength should be 3N/mm2 for characteristic strength greater than 20N.mm2. This gives minimum strength for design grade strengths of 10, 20, 30 and 40N/mm2 as 7, 17, 27, and 37N/mm2 respectively. This rule is achieved for grade strengths of 10,20,30 and 40N/mm2. However, this rule was not achieve for concrete with design strength of 50N/mm2 (Table 2) since the minimum strength in this case is 47N/mm2 and there are strength values of 43.22 and 43.56, 46.44N/mm2 in Table 2 Group 3 under Grade 50 concrete. Compliance interms of maximum or minimum cement content is achieved if the cement content is not less than 95% of the specified minimum or more than 105 percent of the specified maximum. To ensure durability under mild exposure, BS8110:Part 1(16) specified a minimum cement content of 275kg/m3, 325kg/m3 and 400KN/m3 for grades 30,40 and 50 concretes respectively. From Table 4, it can be seen that 455, 530, 550KN/m3 were provided. These are therefore satisfactory. Also BS8110:Part 1(16) imposed maximum free water/cement ratio of 0.65, 0.55 and 0.45 for grades 30, 40, and 50 concretes respectively. Also from Table 4, the water cement ratios of 0.45, 0.36 and 0.31 were provided respectively. Hence, the water cement ratio is satisfactory. In addition, for the strength compliance and acceptance requirement to be pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1591 Innovations (15th – 17th April 2008), Benin City, Nigeria achieved, the maximum value by which any individual test results will fall short of the design grade strength should be 3N/mm2 for characteristic strength greater than 20N/mm2. Thus, the concrete produced from the typical Benin City sitly sands in zone 3 (Ikpoba, Ovia and Okhora erosion sands) produce concrete that are of good quality in all respects, but the concrete is characterized by low compressive strength.

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2nd International Conference On Engineering Research & Development: 1592 Innovations (15th – 17th April 2008), Benin City, Nigeria

Conclusion From the findings of this study, the following conclusions are drawn.  The concrete made with Benin City silty sand could develop strength up to the design compressive grade strength but may not be able to develop the strength margin to justify the probability that not more than 5% of the test results will fall below the mean strength.  The concrete produced from the typical Benin City silty sand are of good quality in all respect but are generally characterized by lower compressive strength.  The concrete produced with these sands can be used in construction but care must be taken provided that the mean strength aimed at, must be higher than the minimum from structural standpoint so that every part of the structure be made of concrete of adequate strength. REFERENCES (2)

R. Jones, and E.N. Gatfield, “Testing concrete by Ultrasonic Pulse Technique” D.S.I.R Road Research Technical Paper No. 34. HMSO. London. 1955.

(3)

A.M. Neville, “Properties of concrete” Third Edition. ELBS/Longmans, Singaporc. 1981.

(4)

British Standard Institution BS5328:Part 4 “Specification for procedures to be used in Sampling, Testing and Assessing compliance of concrete”. BSI, London. 1990.

(5)

O.E Alutu, and B.K. Ifejika, “Strength study of concrete made with various local sands in Benin City, Nigeria”. Advanced Materials Research Vols. 18-19, pp. 21-26. On line at:http://www.scientific.net@2007. Trans Tech Publications Switzerland.

(6)

A. Omoregie and O.E. Alutu “The influence of fine aggregates combinations on particle size distribution, grading parameters and compressive strength of sandcrete blocks.” Canadian Journal of Civil Engineering. Vol. 33, No. 10. pp. 1271-1278. 2006.

(7)

British standard institution. BS882, “Aggregates from Natural sources for concrete”. BSI. London. 1992.

(8)

British Standard Institution, BS812: Part 103, “Method for determination of particle size distribution” BSI. London. 1985.

9)

A.M Nevile and J.J. Brooks “Concrete Technology”. ELBS Edition. Longmans Singaporc Publishers Ltd. 1994.

(10)

E.A Whilehurst, “Soniscope tests on concrete structure” Journal of American Concrete Institute, 47, 1951. pp. 433-444.

(10)

British Standard Institution BS 112: Part 1, “Sampling, shape, size and classification”. BSI. London. 1975.

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2nd International Conference On Engineering Research & Development: 1593 Innovations (15th – 17th April 2008), Benin City, Nigeria (11)

N. Jackson and R. Dhir “Civil Engineering Materials Macmillan”. Press Ltd. London. 1996.

(12)

British Standard Institution, BS 1881: Part 108 (1983), “Methods of making test cubes from fresh concrete.” BSI. London.

(13)

British Standard Institutions, BS 1881:Part 203 “Measurement of the velocity of ultrasonic pulse in concrete”. BSI. London. (1986)

(14)

British Standard Institutions, BS 1881: Part 202, “Recommendation for surface Hardness Testing by Rebound Hammer”. BSI. London. 1986.

(15)

British Standard Institution, BS 1881: Part 116, “Methods for determination of compressive strength of concrete cubes.” BSI. London. 1983.

(16)

British Standard Institution BS110:Part 1 Construction” BSI London. 1985.

“Code of Practice for Design and

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2nd International Conference On Engineering Research & Development: 1594 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08216) DESIGN AND CONSTRUCTION OF A TROLLEY CRANE

Edokpia, R.O. and Omoigui, J.E. DEPARTMENT OF PRODUCTION ENGINEERING UNIVERSITY OF BENIN, BENIN CITY APRIL, 2008 ABSTRACT Lifting and its associated problems are prevalent in most engineering and manufacturing firms. This problem usually hinders the output of such firms. Although attempts have been made to curb this problem, like the invention of the trolley and later the invention of more complex and complicated machines like the pail loader, fork lift, hoists etc. Still this problem persists in small scale manufacturing firms that are not able to hire or purchase such sophisticated machines. Also in large firms, there are portions of the factory floors where these machines (fork lift, pail loaders etc) cannot fit into, for example, narrow gangways. The trolley crane was constructed to reduce and if possible eliminate the above problems. It is actually an evolution of the conventional trolley available in the market and it has special features which enable it to lift objects unto itself and unto other trolleys. It is also an effective machine that will aid road side vehicle technicians commonly called “MECHANICS” in solving the problem of dropping down of engines for repair. Its limitation is the maximum load to be lifted by the machine which is 2460N (246kg). This implication being that most operatives may not be able to quantify very heavy rigid loads to ascertain if they are more than the machines capacity. Even with the limitation, its purpose and design still proves to be a very marketable machine. Experimental results performed with the trolley crane shows that it has an efficiency of 98.2%. Keywords: Trolley Crane, Forklift, Bending moment, Load, Member, deflection 1.

INTRODUCTION Solving existing problems efficiently at the lowest possible cost is the ultimate objective of an engineer and the biggest challenge to Nigerian engineer is the search for the cheapest alternative product due to the persistent increase in the cost of engineering and technological products. Before the introduction of trolleys, loads were conveyed around the factory floor manually or by pulling the load placed on flat boards with a rope or even dragging it on the ground to desired destinations. Technology soon corrected these problems with the invention of industrial trolleys and power trolley as means of conveyance. The two wheel dual carriage was first made mainly for transfer of loads from one place to another. (Andrew, S.H. 1873), introduced the trolley which was used in Sam Francisco while the first street overhead trolley lines were already in use in Germany in 1884. Faustin Potain (1932), introduced the crane “Jib tower” but before then United Railway Electric (1913), later known as Baltimare Company had made a crane called 3715. In the mid-1920s, a competitor crane emerged with a greatly advanced design made by the Differential Steel Company, later known as “Dif Co”. This was an all electric crane. It was the First World War that made the fork lift truck popular mainly due to the shortage of labour. After the war, the truck designers decided that putting loads on top each other would be rather a good idea and so a high version of the platform truck which was already in use since the 1800s was produced. Clark company are credited with producing the forerunner of seated counter balance truck in 1917, but it was Yale company that in 1925, produced the first electric truck that had raising forks and elevating mast. After the First pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1595 Innovations (15th – 17th April 2008), Benin City, Nigeria World War, British industry started importing trucks from the USA and they were used mainly for outside applications but then in 1946 the first truly British Company, Conventry Climax, produced the first lift truck. The invention of these complicated machines (forklifts, hoists, cranes etc) have aided in the transportation of materials and material handing, still, they have their limitations. The forklifts, pail loaders and lift trucks and hoists cannot fit into narrow gangways on the factory floor and in the event that there is a break down of these machines on the factory floor, the manufacturing process usually come to a stand still. Since there may be no substitute machines, operatives still face the risk of ‘lifting and its associated problems’. Also, small scale businesses may not be able to purchase or hire such machines; still they need to lift loads within their factory floor. This is one of the reasons why back ache, a lifting problem, still plagues the manufacturing floors of most small scale firms. Jagboro, Akpoduado and Orido,O(2003) modified the manual four wheel trolley by introducing a hand break which was used to stop the trolley while in motion. Torakan Thomas (2002) made a good model of the four wheel trolley, Ikpama , (2002) of Production Engineering Department, University of benin designed a model of a manual lift truck by using gears and pulleys as its working principle for lifting. The limitation of the trolley available in the market shown in fig 1.0 below is that it cannot lift loads. This means that manual labour must be employed to put loads unto them.

Fig. 1. 1 Conventional Four Wheel Trolley The above sketch of the conventional four wheel trolley is the model on which improvement was made to obtain the trolley crane. The improvement was done so as to try as much as possible to eliminate the ergonomic problem of lifting, help to conserve the operative’s energy in the process, using mechanical principles of moments. 2. DESIGN PRINCIPLES The trolley crane works with the mechanical principle of moments as seen below where R1 is the reaction at the front wheels of the truck and serving as the pivot. PRINCIPLE OF OPERATION

W

x5 W1

x1

A R

Fig.2.1.

x2

x3 WT x4

B W2

Front Elevation of Trolley Crane

WT = Trolley crane weight W1 = Maximum load W2 = Counter load X! = distance of maximum load from pivot R1 X4 = Counter load distance from pivot R1 X2 = trolley crane weight centre of gravity position from pivot R1

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2nd International Conference On Engineering Research & Development: 1596 Innovations (15th – 17th April 2008), Benin City, Nigeria W1 

W2 X 4   WT X 2  ……………………………………………………………………… X1

…………… (1) The principle of moments is the main basis of this work. This is the effect of a dead load (W2) with a distance (X2) greater than that of the load to be lifted by the chain block (X1). For the machine to be able to lift the load (W1), the anticlockwise moment (W2. X4) must be less than the anticlockwise moment (W1. X1). 2.1

DESIGN DRAWINGS

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2nd International Conference On Engineering Research & Development: 1597 Innovations (15th – 17th April 2008), Benin City, Nigeria

2.2DESIGN ANALYSIS The intended trolley crane must have a rigid support for it to be able to lift objects without failure. For this reason, a base frame made of U-channel bar was selected with a mass per length of 7.58 X 10-3 kg/mm. The design of the base is as shown below: 2.2.1 CENTRE OF GRAVITY OF BASE600 4

80

3

80

500

1400 550 Fig2. 2.1: Plan of Base Frame 6 5

Recall

that

2

467.5 …………………………………………….(2) 350 y Where A = Area of member = Length (L) X Breadth (B) 1 = Co-ordinate of the centre of gravity.80 y x 0 MEMBER AREA 80 Y 80 1. 35200 700-46 660 2. 35200 700-350 350 3. 35200 900-700 200 4. 35200 1360-799 660 Where Area = 440 X 80 for all the members above

Y

y

80

Ay A

= = = =

Ay A

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2nd International Conference On Engineering Research & Development: 1598 Innovations (15th – 17th April 2008), Benin City, Nigeria 2.2.2

CENTRE OF GRAVITY OF THE TROLLEY CRANE Considering fig. 3.2 below:, member 4 being the rigid base whose centre of gravity has been determined above, the centre of gravity of the entire figure is calculated below: 358

x

x

1 492.

y

1980

y

40

2

Fig. 2.2.2: Front Elevation of Trolley Crane (Excluding Wheels) 8 FOR MEMBER 1, A = 14320 6 4 y  874.1 83.60

3

6 2

4

x  639.75

467.5

1400

FOR MEMBER 2, A = 77600 y  19.64

1637.5 4

 1940sin280    363.36 x  818.75 -  2  

FOR MEMBER 3, A = 34460  860cos 6.40    466.78 y  894.1 -  2    860 sin 6.40    770.8 x  818.75 -  2  

FOR MEMBER 4, A = 60 × 1400 = 84000 x  818.75 - 467.5  351.25 y  874.1

Ax A x  443.98  X  444mm x

Y

103522808 210320

Y  492.2mm

2.3

DETERMINATION OF RATED LOAD OF THE SYSTEM Consider the figure below:

WL

Fig. 2.2. 3:

620

Trolley Crane with Counter Load R

WT

WL = Live load = Weight of load + Weight of chain block WT = Dead load = Weight of Trolley Crane = 650N WC = Estimated counter load = 600N R = Position of front wheels serving as pivot. The free body diagram of the above is 38 A

156

Wc

150

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2nd International Conference On Engineering Research & Development: 1599 Innovations (15th – 17th April 2008), Benin City, Nigeria

1200 of Trolley Crane Fig 2.2.4: FBD Taking moment about point B, WL.285.5 = (650 x 156.5) + (1200 x 600) WL = 2878.2N. But the chain block weights 333N. Let W = Maximum load to be lifted. WL = W + Weight of chain block 2878.2 = W + 333 W = 2545.2 N. This means that the maximum load to be lifted by the system is 2500N. 2.4 DETERMINATION OF STRENGTH OF THE SYSTEM To determine the strength of the base members considering figure 3.1, Members 1, 2, 3, and 4 are the same and will experience the same uniform load. Also members 5 and 6 are also the same. For this reason, we shall only consider members 1 and 6. 2.4.1 Shear Force and Bending Moment of Member 1 Member 1 as seen in fig.2.2.1 will experience a uniformly distributed load along its W(N/mm) length as seen below:

A

B C (N) WL

WL 2

WL 2

L

Fig. 2.2.5. Front View and Free Body Diagram of Member 1 For the Fig. 2.2.5 above,

R A  RS 

WL  0.5WL Shear 2

force at any section X at a

distance x from A, Fx = RA – Wx = 0.5 WL-Wx Shear force at point A RA = 0.5WL where x = 0 also RB = –0.5WL where x = L Taking moments about B,  Mx  R A .X - W

x 2 WLx WLx 2   2 2 2

Maximum bending moment will occur at the midpoint where X = L which is at the point C 2

on the diagram above. Mc 

WL2 8

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2nd International Conference On Engineering Research & Development: 1600 Innovations (15th – 17th April 2008), Benin City, Nigeria

X B

A

C X

L

A +ve 0.5WL

C

B 0.5WL S.F.

WC2 8

Mx

–ve 1

+ve

Fig.

B.M .

2. A

B

C

2.4.2

1.6.

Bending Moment and Shear Force Diagrams of Member 1 Equation of deflection of Member 1 Recall from double integration method of obtaining deflection of members, EI

d2y  Mx dx 2

From the above diagram, Slope

dy 1  WLx 2 Wx 3      dx EI  4 6 

and its deflection, y, is y

1  WLx 3 Wx 4  ……………………………………………………………………    EI  12 24 

…………..(3) The selected member has the following parameters. Length = 440mm Thickness = 5mm U-channel width = 80mm U-channel height = 40mm Mass/Length W2=7.58 x 10–3kg/mm = 7.58 X 10–2 N/mm. Mass/Length of proof load, W1=proof load/span of support. =2500/440 = 5.68N/mm young modulus E = 2.1 x 105 N/mm2. The U-channel bar has its cross section area as shown below: Reference Axis 1

5

2

70

Neutral Axis

3

5

Fig. 2. 2.7: Cross Section of U-Channel Bar Using Transfer of Axis Theorem, pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1601 Innovations (15th – 17th April 2008), Benin City, Nigeria Ixx (1) 

40 x 5 3  40  37.5 2 12

Ixx (1)  281.66  10 3 mm 3

Ixx (2) 

bd 3 since member 2 coincides with the neutral Axis. 12

Where b = breath and d = depth 

5  70 3  142.9  10 3 mm 4 12

Ixx (3) 

40  53  40  37.5 12

= 281.66 × 103 mm4 Ixx  Ixx (1)  Ixx (2)  Ixx (3)

 706220 mm 4

From Fig. 2.1.6 WL2 . But W = W + W 1 2 8  W  7.58 10-2  5.68 N / mm Mc 





W  5.7558 N/mm 5.7558  4402 Mc  8

Mc=139.290 KNmm 2.4.3 DETERMINATION OF STRESS ANALYSIS OF MEMBER 1 According to the provisions made in clause 19C of B.S449 Part 2:1969, the allowable bending stress of grade 43 (Ikpama, 2002). Mild Steel has Pbc  165N/mm2

But maximum bending stress on Member 1 is  max 

MC I xx

…………………………………………………………………….(4)  3.94 N / mm 2

C = Distance from the centroid to the outer surface of the member (fig 3.6) by symmetry.

Since  max  Pbc , Member 1 is adequately strong enough. 2.4.4 DEFLECTION OF MEMBER 1 According to the provisions made in B.S 449, deflection is limited to L of the span. 360 L  y unit  360 440  360m

= 1.22mm From the equation of deflection, Maximum deflection will occur at x  y max 

L from fig. 2.1.6. But 2

I  WLx 3 Wx 4  …………………(4)    EIxx  12 24 



I  WL4 Wx 4     EIxx  96 384 

y max 

WL4 128 EI

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2nd International Conference On Engineering Research & Development: 1602 Innovations (15th – 17th April 2008), Benin City, Nigeria y max  0.011mm. Since ymax < yunit, it implies that the length of member 1is adequate for deflection.

2.4.5

DESIGN OF MEMBER 6 The bending moment, equations of deflection and shear force diagrams of member six are alike and the same. Their only difference is that of their lengths. 2.4.6 STRESS ANALYSIS OF MEMBER 6 Length = 1400mm Mass/Length = W  7.58 x 10 -2 N / mm 2

Mass/length of proof load, W1 = proof load/span of support = 2500/1400 = 1.79mm W = W1 + W2 = (7.58 x 10-2 + 1.79) = 1.86 N / mm Ixx is same as that of member 1 = 706 220mm4. C = 20 2

Mc 

WL2 4.24 x 1400  8 8

Mc  303800N/MM Mc  303.8KN/mm

Ixx and C are same as that of member 1. Ixx = 706220mm4 C = 20. Recall that Pbc  165N/mm 2 which is the allowable bending stress of grade 43 mild steel according to BS449, Part 2:1969. Maximum bending stress on member 1  max 

MC I xx

303800 x 20 706220  max 8.6 N / mm2

 max

Since  max  Pbc , therefore member 6 is strong enough to withstand the load. 2.4.7 DEFLECTION OF MEMBER 6 Recall y  L unit

360

1400  360

=3.889mm. From equation of deflection 4

ymax 

WL4 1.86 x 1400  128EI 128 x 2.1 x 105 x 706220

ymax = 0.376mm. Since ymas < yunit, the chosen length of the bar is sufficient enough for maximum deflection to occur and not be exceeded. 2.5 DESIGN OF THE CRANE Consider the rigid support below: B C

C

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620

2nd International Conference On Engineering Research & Development: 1603 Innovations (15th – 17th April 2008), Benin City, Nigeria

AB= L

Fig. 2.2.8: Front Elevation of Crane L1=L cos 620 + BC ABC is assumed to be straight and the free body diagram is shown below: C

B

W

L

A

620 D

L X

X W WL1

W

A

D

A

D

1

WL

Wx

Fig. 2.2.9.

Shear Force and Bending Moment Diagrams of Crane Stand

For the above, Fx = – W and bending moment at this section is: Mx = – W.x ……………………………………………………………………….…(5) At point D, bending moment is Zero since x = 0 at this point, also at point A, bending moment is M A   W L

(hogging)

Since x  L

2.5.1

EQUATION OF DEFLECTION OF THE CRANE STAND Mx = – Wx from double integration method of obtaining deflection of members, EI

d2y  Mx dx 2

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2nd International Conference On Engineering Research & Development: 1604 Innovations (15th – 17th April 2008), Benin City, Nigeria EI

d2 y  Wx dx2

y 

- Wx 3 6EI

The selected member has the following parameters. Actual length = L  1980 cos 620  358 = 1287.56mm Mass/Length W2 = 7.58 X 10-3 = 7.58 X 10-2 N/mm Mass/Length of proof load = W1 W1 

2500 1287 .56

W1 = 1.94 W = W1 + W2 = 1.94 + 7.58 X 10-2

 2.02N / mm W  2.02 N / mm

2.5.2

Moment of inertia of member is same as that of members 1 and 6. Ix=706220 mm4 also C = 20 STRESS ANALYSIS OF CRANE Recall that for adequate design, Pbc  165N/mm 2

But maximum bending stress of crane is  max 

Mc Ixx

but M  - WL

= -2.02 X 1287.56 = -25830.87 Nmm –ve meaning it hogs downwards.   max 

25830.87 x 20 706220

 max  0.73

2.5.3

 max  Pbc . This means that the crane is strong enough to withstand the load. DEFLECTION OF CRANE MEMBER Recall that y unit  L  L 360

360

=3.57mm But

y max 

 WX3 WX  Ei6 6EI

Maximum deflection will occur when x = L  y max 

 WL3 6EI

ymax=0.005mm Since ymax < ylimit  the length of the crane is adequate. 2.6 DESIGN OF CHAIN BLOCK The chain block made from mild steel and weighting 333N with a capacity of 8012N was purchased. Since the capacity of the block (8012N) is greater than maximum capacity of the system (2878.1N) the chain block is satisfactory. 2.7 DESIGN OF WHEELS FOR THE TROLLEY CRANE

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2nd International Conference On Engineering Research & Development: 1605 Innovations (15th – 17th April 2008), Benin City, Nigeria

WL

RB

WT

RE WL

Fig. 2. 2.10. Front Elevation of Trolley Crane From the above diagram the Reactions RB and RE signify the points where the wheels are located.

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2nd International Conference On Engineering Research & Development: 1606 Innovations (15th – 17th April 2008), Benin City, Nigeria WL

156.5

385 A B

WL

C

RB

WT 1200

E

D

F

RE 12500

Fig. 2.2.11 FBD of Trolley Crane WL=2878.2N WT=650N WC=600N Considering y = 0 at equilibrium, +ve –WL+RA–WT–WC+RB = 0 R B + R E = WL + WT + WC RB + RE = 2878.2 + 650 + 600 RB + RE = 4128.2…………………………………………………………………….………(6) Taking moment about point B, MB = 0 -385WL + 156.5 WT + 1200WC-1250 RE = 0 -385(2878.2) + 156.5(650) + 1200(600) = 1250RE -1108107 + 101725 + 720000 = 1250RE -286382 = 1250RE RE = – 229.1056 N From equation 6, RB = 4128.2 – (- 229.1056) RB = 4357.3N Since there are two wheels in front and two at the back, the reaction per wheel at: (a) the front wheels 

(b)

R B 4357.3   2178.6 N 2 2

the rear wheels R E 229.1   114.55 N 2 2

Four stationary castors of carrying capacity of 250kg were chosen. The wheels have diameters of 100mm and a width of 27mm. 2.8 DESIGN OF BOLT FOR THE ATTACHMENT OF THE CRANE FRAME TO THE BASE OF THE TROLLEY Four bolts are employed for this purpose. Each is expected to carry load Q as expressed below: Shear load/bolt; Q= total load carried/no. of bolts Q 

2878.2  719.55N 4 I

Q Q

Fig. 2.2.12.

Cross Section of Bolt System

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2nd International Conference On Engineering Research & Development: 1607 Innovations (15th – 17th April 2008), Benin City, Nigeria The bolts are subjected to shear stresses as a result of the forces acting on them. The allowable shear stress for bolt connection as stated in clause 50 of B.S. 449:1969 is  au  80 N / mm 2 But   Q where A = Area au

A = d

2

min

/4

Thus  au 

A

where dmin = diameter of bolt. 4Q d 2 min

Thus d min  4719.55 /  80   11.452

dmin= 3.38mm. This means that a safety design will involve using bolts of nominal diameter greater than 3.38mm. Therefore any bolt which has its normal diameter greater than 4mm can be used to hold the frame to the trolley base. 3.0 COST ANALYSIS AND OPTIMIZATION The cost of this project is grouped into the following categories for easy analysis. These are 3.1 Material Cost This is the cost of items, components, or parts used in the fabrication of the trolley crane. A general analysis of the materials/cost is given below. S/N Description of material Total price 1. Mild steel U channel bar N5,000 2. Chain block. N12,000 3. 4 Rollers. N1,000 4. Wood platform N500 5. Medium carbon steel rod N80 6. Bolts and nuts. N200 7. Concrete aggregates N500 Total N19,280 3.2 Fabrication Cost The fabrication of this trolley crane was done locally. Therefore cost given here was obtained from price billing of technicians, the price breakdown is shown below. 3.3 Miscellaneous Cost JOB DESCRIPTION CUTTING WELDING AND DRILLING

COST(N) 1,800

ASSEMBLY MACHINING/FINISHING/PAINTING TOTAL

200 500 2,500

This cost is cost incurred due to transportation/materials carriage which we summed up to be N1800. Finally the total cost therefore calculated is Material cost N19280 Fabrication cost N2500 Miscellaneous cost N5000 Total N23,580 3.4 MANUFACTURING PROCEDURE The sequence of the manufacturing process is tabulated below: PROCUREMENT OF Materials were locally sourced. MATERIALS MARKING OUT This was done with the use of scriber, tape rule, steel rule pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1608 Innovations (15th – 17th April 2008), Benin City, Nigeria

CUTTING OPERATION BORING OPERATION WELDING OPERATION ASSEMBLING OF PARTS FINISHING

PAINTING

and centre punch. The U-channel bars were cut to size after marking out using Hack saw and bench vice to hold in position. Drilling machine was used in boring holes for nuts and bolts unto the marked out base frame and wooden platform. Arc welding machine was used to weld the base frame components and crane components in position. The parts were assembled using the appropriate size of spanners to bolt the parts in position. The finishing operation was done using the hand grinding machine to remove sharp edges, smoothen surfaces and dress welded joints. Painting was done using an antirust paint prevent rusting.

4.0

PERFORMANCE EVALUATION PROCEDURE: Use the hook of the crane to pickup loads of 1000, 1200, 1400, 1600, 1800 to 2000 N respectively. Determine the effort needed to pull the chain and lift the loads to know and record the distances moved by both loads and effort. Calculate the Mechanical Advantage (M.A.), Velocity Ratio (V.R.) and efficiency of the system. l =Distance the load moves, h = distance the effort moves Table 4.6.1

Readings of Experimental Results

Load (N)

Effort (N)

l(mm)

h(mm)

1000 1200 1400 1600 1800 2000

90 90 90 90 90 90

98.0 100.0 24.0 7.0 49.0 45.0

1114.0 1336.0 389.0 127.0 998.0 1008.0

Average Efficiency 

M.A 

Load Effort

11.11 13.33 15.56 17.78 20.00 22.00

V.R. 

h l

11.37 13.36 16.21 18.14 20.36 22.4 Total

Efficiency 

M.A. V.R 0.978 0.998 0.960 0.980 0.982 0.992 5.89

5.89  0.982 . This shows that the efficiency of the machine is about 6

98.2%. 5.0 SUMMARY The trolley crane was designed and built with locally sourced materials and components. However the chain block is imported and it is readily available. However the material outline and frame work were locally sourced and some were fabricated. The existing product in the market which is the four wheel trolley cart was examined and improvement was based on its features. Firstly, it takes 6 hours to produce a unit of the trolley crane and 9 hours to say the least. The limitation of this machine is that the maximum capacity it should lift is 2500N. This means that it should not be used to raise any load that weighs more than 250Kg because the machine will fail above this loading limit. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1609 Innovations (15th – 17th April 2008), Benin City, Nigeria Whereas the four wheeled trolley can only be used to transport loads, trolley crane can selfload and also load other trolleys as well as serve as the four-wheel-trolley. 6.0 CONCLUSION Based on the foregoing results and dimensions, the following optimal can be expressed: i. The trolley crane is capable of lifting and loading loads up to 2500N and can also be used to “drop” the engine of light vehicles with sedan or coupe models. ii. The trolley crane has great potentials for commercial production, in the sense that existing machines doing the same services are too costly for small scale engineering entrepreneurs and firms. Therefore, the trolley crane is technically and commercially viable. iii. Energy consumption is low and there is also time saving in batch production. iv. It is very durable because the major components that are involved were treated after finishing and then material selection was carefully considered. 7.0 RECOMMENDATIONS This project was aimed at reducing and if possible eliminating lifting problems. The trolley crane is manually operated and therefore material handling is a problem with this process. Thus, it is therefore recommended for further works that the system should be automated to minimize the problem of handling thereby improving on the quality.

REFERENCES Brown, H.B. and Bryan A.J. (1937), “Engineering Science” 1st edition, published by Macmillan and Co. Ltd, London. Colin, C. (1998), “Kent’s Mechanical Engineers Handbook” 72nd edition, by John Wiley and Sons Inc., New York, U.S.A. Constrado(1983), “Steel Designers’ Manual”, 4th edition (revised), by Granada publishing Ltd, London, P. 812, 816-821. Creamer H. R.(1984), “Machine Design” 3rd edition, by Addison – Wesly Publishing Company, Inc, California, U.S.A. p. 326, 401. Darford K., Morris T, Elaine L(1989), “The New Illustrated Science and Invention Encyclopaedia”, vol. 25, H.S. Stuttman Inc., WestPoint, Connecticut, USA, P. 3436, 3437. Ejiofor, G. C.(1984)“Design of a Bridge Crane with a Capacity of three tones” B.Eng project report, Department of Production Engineering, University of Benin, Benin City, Nigeria. George S. B., Henry R.(1991) “Material Handbook” 13th edition, published by McGraw-Hill, Inc, New York, USA. Hall A.S. Holowenko A.R. and Laughlin H.G.(1980), “Machine Design” SI (metric) edition, published by Schaum’s outline series of McGraw-Hill book company, New York, USA, P. 133, 114, 156-162, 178-183, 205, 206, 222-229. Ian McNeil,(1990)“An Encyclopaedia of the History of Technology” 1st edition, Rutledge Publisher, London. P. 1, 2, 16, 17. Ibhadode A.O.A.(1998) “Introduction to Manufacturing engineering”, 1st edition, by Abik Press, Benin City, Nigeria. p. 95. Ikpama E.J. (2002),“Design and Construction of a Manual Lift Truck”, B.Eng project report, Department of Production Engineering, University of Benin. Jagboro, A. Akpoduado, and Orido, O.(2003), “Construction of a two wheel dual carriage hand trolley”,hnd project report, Department of Mechanical Engineering, Petroleum Training Institute, Effurun. Cooke J.(2004) “Multimedia Handbook for Engineering Design”, University of Bristol, http://www.dig.bris.ac.uk/hbook. Kempe’s engineering year book, 82nd edition, vol. 1 by Morgan-Grampian Polishers Ltd, London. Khurmi R.S.(2002), “A Textbook of Engineering Mechanics” S. Changd and Company Ltd. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1610 Innovations (15th – 17th April 2008), Benin City, Nigeria Khurmi R.S.(2004), “Strength of Materials” S. Chand and Company Ltd. Manutan Industrial Equipment Catalogue, 32 Bis boulevard, Paris, France. Matthias N. F (1974), “The Rail Road Car Builder’s Pictorial Dictionary” dover publications, inc, Canada. Michael F. A, and David R.H(1986) “Engineering Materials” 1st edition, by Pregamon press, Headington Hill hall, Great Britain. P. 258, 255. Parrish A, “Mechanical Engineering Reference Book”, 11th edition, Butterworth and Co. (publishers) Ltd, London 1973, P. 12-16. Plant Engineering Magazine(1974), “A look back at lift vehicles”, p. 74. Tony S (2004) “A puffed History of Forklift Trucks” A.E.S. Training Services. http://ask.com/aes training services Torakan, T. (2002), “Construction of Trolley”hnd project report, Petroleum Training Institute, Effurun.

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2nd International Conference On Engineering Research & Development: 1611 Innovations (15th – 17th April 2008), Benin City, Nigeria (ICERD 08242) EFFECTS OF LINEAR ALKYL BENZENE SULFONATE DETERGENT ON THE ACTIVITY OF CASSAVA FERMENTING ENZYME E. T. AISIEN, E. R. ELAHO and *F. A. AISIEN *Department of Chemical Engineering, University of Benin, Benin City. [email protected]

Abstract The effect of linear alkyl benzene sulfonate (LAS) detergent on the activity of cassava fermenting enzymes was investigated for 72 hrs. Enzymatic assay methods were used to determine the activity of cassava fermenting enzymes: cellulase, á-amylase, pectin methyl esterase and phosphorylase. The cassava fermenting media were made up of LAS detergent concentration of between 1g/L to 5g/L. The results show that the LAS detergent of 2g/L and 3g/L gave optimum enzyme activity. The order of enzyme activity was pectin methyl esterase > á-amylase > phosphorylase > cellulase. Keywords: Detergent, fermenting cassava, enzyme activity, cellulase, media 1. Introduction Nigeria is presently the world largest producer of cassava (Manihot esculenta Crantz), with the current production rate of about 47 million metric ton per year. Okafor and Ejiofor [1] reported that cassava is an important dietary staple and the cheapest source of calories for over 50 million peoples in the tropical developing countries of the world. Traditionally, cassava fermentation is a practice that leads to either reduction or complete elimination of poisonous cynogenic glucosides (linamarine and lotaustraline) present in cassava [1, 2]. Aisien and Aisien and Aisien [3] reported that some lactic acid bacteria (Leunconostoc messenteriods, Lactobacillus plantarum, Corynebacterium Manihot, Bacillus subtilis, Pseudomonas alcoligens, Pseudomonas aeruginosa and Citrobacter fruedii) have been implication in the fermentation of cassava. Aisien and Aisien [3] reported the use of detergent to enhanced cassava fermentation in Southern Nigeria. Detergents have been reported to have marked germicidal properties and causes protein denaturation and enzyme inhibition [4] Also, Reese and Maguire [5,6] reported that surfactants/ detergents enhanced enzyme production by microorganisms. In an earlier study on the effects of detergent on cassava fermentation, the centre focus was on its effects on fermenting microorganisms present. However, in this present study, emphasis is on the effects of detergent on the activities of cell wall degrading enzymes (cellulase, á-amylase, pectin methyl esterase polygalacturonase, phosphorylase and xylanase). Previously, not much is known about the biochemical changes that bring about the process of tissue softening, however, cell-degrading enzymes have been implicated in the past [7]. Therefore, the aims of this study is to determine the effects of anionic detergents, linear alkyl benzene sulfonate (LAS) detergent on the activity of cassava cell wall degrading enzymes (cellulase, á-amylase, phosphorylase and pectin methyl esterase). 2. Materials and Methods 2.1 Material collection Freshly harvested cassava tubers of cassava sweet variety were obtained from a farm in University of Benin, Benin city. The tubers were about 16months old. A non- enzyme washing detergent, anionic detergent ([C12H25SO3]+Na+) (linear alkyl benzene sulfonate) was purchased from Oba market, Benin City. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1612 Innovations (15th – 17th April 2008), Benin City, Nigeria 2.2 Preparation of test fermentation media The fermentation study was carried out using 5- litre plastic bowls A, B, C, D, E and F. Mature cassava tubers were peeled, washed with clean tap water and their sizes were reduced to small pieces (10g per piece) using a sharp knife. 250g of this cassava tuber pieces were transferred into each plastic bowl containing 1 litre clean tap water. Detergents was added to bowls A, B, C, D and E such that the fermenting media were made up of detergent solution of concentrations 1g/l, 2g/l, 3g/l, 4g/l and 5g/l respectively. Bowl F was the control without detergent. All the bowls were allowed to ferment for 72hrs. The fermenting cassava tuber pieces were removed from the fermenting water every 24hrs interval for enzyme assay.

2.3

Biochemical analysis

Enzyme assays Cellulase and á-amylase activities were assayed Nelson-Somogyi method [8]. Pectin- methyl esterase and phosphorylase activities were assayed using the methods of Awad and Young [9] and Crabtree and Newsholme [10]. 3. Results and discussion Figure 1 shows the effect of LAS detergent concentration on cellulase activity. The activity of cellulase in 1g/l, 2g/l and 3g/l cassava fermenting media increased steadily within the first 48hrs. Cellulase activity then increased sharply between 48hrs. and 72hrs. Also, the results show that the order of cellulase activity was 3g/l > 2g/l > 1g/l. The increase in activity of cellulase is an indication that at low LAS detergent concentration (1g/l – 3g/l) has a marked stimulating effect on cassava fermentation. However, at high concentrations (4g/l and 5g/l) there was gradual decrease in cellulase activity with time. It shows that at higher LAS detergent concentration, the enzyme experienced an inhibitory effect. These results agreed with that reported by Horton et al, 1992 and Razin and Barash, [4] reported that small amounts of surfactant increased enzymes apparent activity, while large amounts cause general cell disruption and enzyme denaturnation. Besides, it was observed that in the control fermenting media (without LAS detergent), the cellulase activity was between that of high detergent concentrations and that of low detergent concentrations. This was however, supported by Reese and Maguire, [6] that low detergent concentrate facilitate access of substrate to enzyme, hence increased enzymes activity while high amounts, alter the permeability of the enzymes and in some cases destroys its selectivity.

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2nd International Conference On Engineering Research & Development: 1613 Innovations (15th – 17th April 2008), Benin City, Nigeria

Cellulase activity (ìmol/min/ml)

0.06 Control 2g/L 4g/L

0.05

1g/L 3g/L 5g/L

0.04

0.03

0.02

0.01

0 0

12

24

36

48

60

72

Fermentation time (Hr.) Figure 1: Effect of LAS concentration on cellulase activity

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2nd International Conference On Engineering Research & Development: 1614 Innovations (15th – 17th April 2008), Benin City, Nigeria

0.08

á-amylase activity (ìmol/min/ml)

0.07 0.06 0.05 0.04 0.03 0.02 Control 2g/L 4g/L

0.01

1g/L 3g/L 5g/L

0 0

12

24

36

48

60

72

Fermentation time (Hr.) Figure 2: Effect of LAS concentration on amylase activity

The control medium experienced cellulase activity in between that of higher detergent concentrations and that of low detergent concentrations. The decrease in enzyme activity with fermentation time in the control medium suggests that leaching from the cassava occurred, therefore reducing the concentration of endogenous enzymes in the cassava media. Figure 2 shows the effect of LAS detergent concentration on pectin methyl esterase activity. The pectin methyl esterase activity was higher than that of cellulase activity. However, the trend observed in pectin methyl esterase activity was similar to that of the cellulase activity with maximal activity at 3g/l. The same explanations and reasons for the variation of cellulase activity with LAS detergent concentration are applicable to that of pectin methyl esterase activity. At the beginning of the fermentation that is at zero hour, there was little difference in enzyme of activity obtained for both the control and the test media. This indicated the presence of endogenous cell wall degrading enzymes present in the cassava. Figure 3 shows the effect of LAS detergent concentration on phosphorylase activity. The phosporylase activity for all the test media (1g/l, 2g/l, 3g/l, 4g/l and 5g/l) increased in the first 24hrs. This was followed by decrease in activity with increase LAS detergent concentration. These results agreed with that reported by Okolie and Ugochukwu, [7]. They reported that “á – amylase and phosphorylase do not seem to play any significant part in the fermentation of cassava”. Figure 4 shows the effect of LAS detergent concentration on á– amylase activity. There was no particular pattern for the variation of

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2nd International Conference On Engineering Research & Development: 1615 Innovations (15th – 17th April 2008), Benin City, Nigeria

Phophorylase activity (ìmol/min/ml)

0.06

0.05

0.04

0.03

0.02

0.01

Control 2g/L 4g/L

1g/L 3g/L 5g/L

0 0

12

24

36

48

60

72

Fermentation time (Hr.) Figure 4: Effect of LAS concentration on phophorylase activity

Pectin m ethy l esterase activity (ìm ol/m in/m l)

0.4 0.35 0.3 0.25 0.2 0.15 0.1

Control 2g/L 4g/L

0.05

1g/L 3g/L 5g/L

0 0

12

24

36

48

60

72

Fermentation time (Hr.) Figure 3: Effect of LAS concentration pectin methyl esterase activity

on

á– amylase activity with fermentation time. However, the trend seem to be opposite of that observed in cellulase and pectin methyl esterase. These results not only agreed with that reported by Okolie and Ugochukwu [7], it supports the facts that á – amylase and phosphorylase are not actually cell wall degrading enzymes associated with cassava fermentation. 4.

Conclusions

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2nd International Conference On Engineering Research & Development: 1616 Innovations (15th – 17th April 2008), Benin City, Nigeria The following conclusions can be drawn from this study:  the presence of LAS detergent in the fermenting media either has an inhibitory or stimulating effect on cassava fermentation depending on its concentration.  low LAS detergent concentration (1g/l, 2g/l, and 3g/l) increased the activity of celllulase and pectin methyl esterase,  high LAS detergent concentration (4g/l and 5g/l) decreased the activity of cellulase and pectin methyl esterase,  the order of activity of cellulase and pectin methyl esterase in presence of LAS detergent is 1g/l > 2g/l > 3g/l >control > 4g/l > 5g/l.  the effect of LAS detergent concentration on á – amylase and phosphorylase activities was quite opposite to that of cellulase and pectin methyl esterase,  cellulase and pectin methyl esterase are the main cell wall degrading enzymes involved in cassava fermentation. References [1] N. Okafor and M.A.N. Ejiofor. “The microbial breakdown of linamarine in fermenting pulp of cassava (Manihot esculenta Crantz)” Mircen J. 2: 327338, (1986). [2] S. C. Kobawila, D. Louembe, S. Keleke, J. Hounhouigan and C. Gamba. “Reduction of the cyanide content during fermentation of cassava roots and leaves to produce bikedi and ntoba mbodi, two food products from Congo” African J. Biotec. Vol. 4 (7) pp 689-696, (2005).

[3] E. T. Aisien and F. A. Aisien. “The effects of detergent on the microbiological changes of fermenting cassava for Fufu production” Adv. Mat. Res. vols 18-19, pp145-150, (2007). [4] S. Razin, and V. Barash “Solubilization of Mycoplasma membrane by the non-ionic detergent Triton X-100”. Appl.Microbiol pp 5255. (1968). [5] E.T. Reese, and A. Maguire. “Increase in yields by the addition of surfactant in Trichoderma viride”. Appl.Microbiol.17,pp 17- 20 (1969). [6] E. T. Reese, and A. Maguire “Surfactants as stimulants of enzyme production by microorganisms” Appl.Microbiol pp17, 242 (1969). [7] P. N. Okolie and E. N. Ugochukwu “Changes in activities of cell wall degrading enzymes during fermentation of cassava (Manihot esculenta Crantz) with Citrobacter freundii” J. Sci. Food Agric. 44: 51-61, (1988). [8] N. Nelson “A photometric adaptation of the Somogyi method for the determination of glucose”. J.Biol.Chem 153:375-380. (1944) [9] M. Awad and R. E. Young.

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2nd International Conference On Engineering Research & Development: 1617 Innovations (15th – 17th April 2008), Benin City, Nigeria “Post-harvest variation in cellulose, polygalacturonase and methyl esterase in avocado (Pesea americana Mill.cv.Fuerte) fruit in respiration and ethylene production” Plant physiol. 64, pp 306-308. (1979) [10] B. Crabtree, and E. A. Newshole “The activities of phosphorylase, hexokinase, phosphofructokinase, lactate dehydrogenase, and the glycerol-3-phosphate dehyrogenase in muscles of vertebrates and invertebrate” Biochem. J. 126 49-58. (1972).

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2nd International Conference On Engineering Research & Development: 1618 Innovations (15th – 17th April 2008), Benin City, Nigeria

(ICERD 08239) BATCH TREATMENT OF PALM OIL MILL EFFLUENT AISIEN, F. A., OJARIKRE, A. A. and AISIEN, E. T. Department of Chemical Engineering, University of Benin, Benin City.

ABSTRACT Batch treatment of palm oil mill effluent (POME) was investigated using physical, chemical and biological methods. Physiochemical parameters such as pH, sulphate (SO42-), total dissolved solids (TDS), total suspended solid (TSS), total solid (TS), chloride ion (Cl-), and biological oxygen demand (BOD), chemical oxygen demand (COD) and metals (Fe2+, Zn2+, Ca2+ and Mg2+) concentrations were determined using American Public Health Association (APHA) methods. The results revealed that treatment was achieved at each stage. However, the biological method proved to be the best with percentage reduction of 45.6%, 97.6%, 71,0%, 50.1%, 80.4%, 93.8%, 72.0%, 85.4%, 93.2%,77.7%, 86.2% and 85.7% for pH, SO42-, TS, TDS, TSS, Cl-, BOD, COD, Fe2+, Zn2+, Ca2+ and Mg2+ respectively. The results conformed to the FEPA and WHO recommended acceptable limit standard. Keywords: Batch treatment, heavy metals, biological method, BOD, COD and POME

1. Introduction Nigeria is the third largest producer of palm oil in the world. The palm oil mill is one of the most important agro industries in Southern Nigeria. It is useful for the survival of Nigerian economy, as sources of basic raw materials for most industrial processes [1]. An enormous amount of palm oil effluent (POME) is generated from oil palm production. Ahmad el at [2] reported that 2.5 – 3.5 tons of POME is generated for every ton of crude palm oil produced. They stated that the fresh POME is a colloidal suspension containing 95 – 96% water, 0.6 – 0.7% oil and 4 – 5% total solids including 2 – 4% suspended solids that are mainly debris from the palm oil fruit mesocarp [2]. POME contains some fertilizing compounds which are useful to the soil. These include nitrogen (N), phosphorus (P), potassium (K) and Magnesium (Mg). However, utilization of raw POME could lead to soil deterioration because of its high concentrations of oil, grease, organic acids and nitrogen compounds [3] (Environmental Management Guid, 1997). Also, untreated POME contains a high concentration of free fatty acids, sodium salts, glycerin, crude oil solids, starches, proteins and plant tissues [4] [BorjaPadilla and Banks, 1993]. It has a high BOD making it a hundred times more polluting than domestic sewage [5] [Maheswaran and Singam, 1997]. Hence the discharge of POME without proper treatment into the environment causes serious environmental pollution. This is include, destruction of terrestrial and aquatic lives, poor water quality for both surface and underground water, oxygen depletion and other related effects, Green house effect and foul smell in and around the industry [6] [Puetpaiboon & Hanasak, 2001]. Various methods have been employed in the treatment of POME; this includes natural evaporation at reservoirs, production of bioenergy such as hydrogen, methane and ABE (acetone, butanol and ethanol), production of single cell protein for animal feeds and biological treatment using anaerobic and aerobic system [7]. The drawbacks of these methods have necessitated this present research that combines physical, chemical and biological treatment methods to achieve a better and a more environmental friendly and acceptable POME. Therefore, the aim of this study is the treatment of POME to the minimum acceptable FEPA [8] and WHO [9] standard.

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2nd International Conference On Engineering Research & Development: 1619 Innovations (15th – 17th April 2008), Benin City, Nigeria 2.

Materials and methods

2.1 Samples collection 20 litre plastic container was used to collect the POME from Nigeria Institute of oil palm research (NIFOR) NIFOR – Benin, Nigeria. Pure culture of Pseudomonas spp. and Flavobacteria were obtained from Microbiology laboratory, University of Benin, Benin City. All the reagents used were of analytical grade, were obtained from Chemical Engineering laboratory store, University of Benin, Benin City. 2.2 Methods The research was designed in as batch process made up of four stages. Stage 1: filtration after boiling, stage 2: sedimentation using aluminum sulphate (alum), stage 3: clarification using hydrogen peroxide and stage 4: biological treatment (anaerobic) using pseudomonas spp. and Flavobacteria. In the first stage, 4 – litres of POME was transferred into a stainless bowl and boiled for 30mins. The boiled sample was cooled to laboratory temperature (30 ± 2oC) and filtered into conical flask using a buckner funnel with a suction pump. 20g of ground aluminum sulphate was added to 3litres of POME in the second stage. The aluminum sulphate – POME solution was left for 2hrs to sediment. The fairly clear solution from stage 2 was furtherly clarified in stage 3 by adding 15cm3 hydrogen peroxide and left for another 1hr. In the fourth stage, the clear POME solution was transferred into a digestion flask. Pure culture of Pseudomonas spp. and Flavobacteria were inoculated into the flask and left in an anaerobic condition at laboratory temperature for 7days. The concentrations of the physiochemical properties such as: pH, BOD, COD, TSS, TDS, SO42-, Cl-, Fe2+, Ca2+, Mg2+ and Zn2+ for the treated POME from each stage and the untreated POME were carried out using APHA [10 ] standard methods of analysis. The metals concentration was determined using atomic absorption spectrophotometer. 3.

Results and discussion

The results of physio-chemical properties (pH, BOD, COD, TSS, TDS, SO42-, Cl-, Fe2+, Ca2+, Mg2+ and Zn2+) of treated POME from each stage and the percentage reduction of the various parameters are shown in Tables 1 and 2 respectively. The variation of pH at different stages revealed that there was a gradual reduction in pH from the untreated POME (12.5) to the fourth (last) stage treated POME (6.78). The percentage reduction in pH was 45.6% at the last stage. The pH value was within the acceptable range of 6.5-8.0 given by FEPA [9] and WHO [10]. This was as a result of the combination of various treatment methods. The variation of the sulphate (SO42-) and chloride (Cl-) concentrations were 84.20mg/l and 130mg/l respectively for the untreated POME. The SO42- and Cl- concentrations decreased to 2g/l and 8g/l and the percentage reductions were 97.6% and 93.8% respectively in the last treatment stage. The concentrations of SO42- and Cl- were lower than the acceptable minimum FEPA [9] and WHO [10]. BOD and COD for the untreated POME were 32.2mg/l and 85.4mg/l respectively. The high BOD and COD is an indication of the presence of large amount of organic and inorganic materials in the untreated POME. The results show that there was a gradual reduction in BOD and COD from stage1 to stage 4. The percentage reduction in stage 4 for BOD and COD were 72% and 85.4% respectively. The significance of the reduced BOD and COD can not be overemphasized, for it will prevent the problem associated with the competition for oxygen within the aquatic environment and hence loss of aquatic life is prevented. The BOD and COD of the treated POME from the last stage were within the minimum acceptable limit by FEPA and WHO. The concentrations of Fe2+, Zn2+, Ca2+ and Mg2+ for the untreated POME were 62.3mg/l, 9.2mg/l, 16.3mg/l and 12.2mg/l respectively. There was drastic reduction in Fe2+ from stage 1 to stage 4. The

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2nd International Conference On Engineering Research & Development: 1620 Innovations (15th – 17th April 2008), Benin City, Nigeria percentage reduction of Fe2+ in stage 4 was 93.2%. However, the reduction in Zn2+, Ca2+ and Mg2+ were gradual from stage 1 to stage 4. The percentage reductions of Zn2+, Ca2+ and Mg2+ in the last stage were 77.7%, 86.2% and 85.7% respectively. The concentrations of metals were within the acceptable limit FEPA and WHO. The concentrations of TSS, TDS and TS for the untreated POME were 42.2mg/l, 18.5mg/l and 60.7mg/l respectively. The results show that the concentrations of TSS, TDS and TS decreased gradually from stage 1 to stage 4 and the percentage reductions in stage 4 were 80.4%, 50.1% and 71% respectively. It was observed that the values were within FEPA and WHO acceptable limit. 4.

Conclusions

The following conclusions can be drawn from this study:  The POME can be treated to acceptable level for discharge into the environment by the combination of simple physical, chemical and biological treatment methods.  The biological treatment method gave the best results that is, highest percentage reduction.  The concentration of the physiochemical properties at the fourth stage of treatment process were within the recommended FEPA and WHO limits.

Table 1: Physio-chemical properties of palm oil effluent water Parameters pH SO42-(mg/l) TS (mg/l) TDS (mg/l) TSS (mg/l) Cl- (mg/l) BOD (mg/l) COD (mg/l) Fe2+ (mg/l) Zn2+ (mg/l) Ca2+ (mg/l) Mg2+ (mg/l)

0 12.50 84.20 64.24 20.00 44.24 130.0 52.09

1 10.00 42.00 35.42 14.99 20.43 62.50 27.09

Stage 2 9.20 18.00 28.68 13.00 15.68 32.00 25.00

3 8.00 12.00 26.22 11.99 14.23 13.00 19.77

4 6.80 2.00 18.62 9.99 8.63 8.00 14.58

90.69

63.20

49.61

37.92

13.27

73.63 12.30 14.47 14.57

43.75 10.11 10.49 12.35

20.00 8.13 6.24 9.01

13.13 6.59 5.24 4.94

5.00 2.74 1.99 2.09

References

Ahmad A.L, Ismail S. and Bhatia S. (2005) “Membrane Treatment for Palm Oil Mill Effluent: Effect of Trans membrane Pressure and cross flow velocity”, Journal on Desalination, 179, pp. 245-255. Ahmad A.L, Ismail S. and Bhatia S. (2003) “Water Recycling of Palm Oil Mill Effluent using MembraneTechnology”, Journal on Desalination, 157, pp.87-95.

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2nd International Conference On Engineering Research & Development: 1621 Innovations (15th – 17th April 2008), Benin City, Nigeria Borja R.,(1996),“Anaerobic treatment of palm oil mill effluent in a two-stage up-flow anaerobic sludge blanket system”, Biotechnology, 45, pp. 125-135. Table 2: Percentage reduction of physiochemical properties of palm oil effluent

Friends of the Earth, “Greasy palms – palm oil, the environment and big business” (www.foe.co.uk/resource/reports/greasy_palms_impacts.pd f) http://www.uga.edu/fruit/oilpalm.htm Ma A.N., (2000), “Palm Oil Developments”, Journal on Palm Oil Processes, 30, 1 – 10. Metcalf and Eddy, (2004), “Wastewater Engineering: Treatment, Disposal and Reuse”, 4th edition, McGraw-Hill, Singapore. Puetpaiboon U. and Chotwattanasak J.,(2001)“Anaerobic treatment of palm oil mill wastewater under mesophilic condition”, pp. 2 – 8.

Parameter s pH SO42(mg/l) TS (mg/l) TDS (mg/l) TSS (mg/l) Cl- (mg/l) BOD (mg/l) COD (mg/l) Fe2+ (mg/l) Zn2+ (mg/l) Ca2+ (mg/l) Mg2+ (mg/l)

1 20.0 50.1

Stage 2 3 26.4 36.0 78.6 85.7

4 45.6 97.6

47.1 25.1

55.4 35.0

59.2 40.1

71.0 50.1

53.6

64.4

69.7

80.4

51.9 47.9

75.4 52.0

90.0 62.0

93.8 72.0

30.3

45.3

58.2

85.4

40.6

72.8

82.2

93.2

17.8

34.0

46.4

77.7

17.5

56.9

63.8

86.2

15.2

38.2

66.1

85.7

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2nd International Conference On Engineering Research & Development: 1622 Innovations (15th – 17th April 2008), Benin City, Nigeria BIO-TREATMENT OF BREWERY EFFLUENTS USING ENZYMES

F. A. AISIEN, G. A. OYKHIOLOMEN and E. T. AISIEN *Department of Chemical Engineering, University of Benin, Benin City.

[email protected]

ABSTRACT The feasibility of treating brewery effluent using bio-catalysts (enzymes) was investigated. Carbohydrase, lipase, protease and a mixture enzyme made of carbohydrate and lipase were used. Brewery wastewater samples were collected and analyzed for 96 hrs, at 12 hrs. intervals. The physiochemical properties (biological oxygen demand BOD, chemical oxygen demand COD, total suspended solid TSS, total dissolved solid TDS, pH, phosphorus (PO4), ammonium nitrogen (NH4-N), Total Hydrocarbon (THC)) were determined using APHA standard method of analysis. The concentrations of the physiochemical properties of the brewery effluent decreased with increasing biodegradation time, for the various enzymes used. However, the different enzymes gave different percentage reductions of each of the physiochemical properties. The order of percentage reduction for the enzyme systems is mixed enzyme > carbohydrase > lipase > protease > control. Hence, the mixed enzyme gave the best results of 90%, 90%, 50%, 100%, 91.6% and 100% reductions for COD, BOD, TSS, NH4-N, PO4 and THC, respectively after 96hrs. of biotreatment. However, the control gave the least percentage reductions of 6.9%, 5.3%, 16.4%, 7.1%, 5.8% and 50.0% for COD, BOD5, TSS, PO4, NH4-N, and THC respectively. Keywords: Brewery effluent, enzyme, biodegradation time, BOD5, total suspended sold.

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2nd International Conference On Engineering Research & Development: 1623 Innovations (15th – 17th April 2008), Benin City, Nigeria 1.

Introduction

The growth and expansion of brewery industry in Nigeria have resulted in the generation of enormous volume of brewery effluent or brewery waste water. Proper management of brewery effluent is a critical and practical problem among most brewery industries in Nigeria. This is as a result of poor local environmental legislation in the country; hence brewery effluents are indiscriminately discharged into the surrounding surface water bodies (rivers, streams, lakes, seas etc.) without any appropriate treatment. It has been reported that brewery effluents are generated from brewery processes such as raw material handling, wort preparation, fermentation, filtration, CIP, packing etc [1]. Also it was reported that brewery effluent contains organic components which are biodegradable (sugar, soluble, starch, ethanol, volatile fatty acids etc.), solid components (spent grains, kieselghur, waste yeast and trub), nitrogen and phosphorus [2]. It is due to the composition of brewery effluent that when it is discharged without proper treatment causes serious environmental pollution of both surface and underground water bodies. The associated problems include algae bloom, reduction in dissolved oxygen concentration, loss of aquatic lives and destruction of vegetation. However, brewery effluent is useful in following areas:  spent grains, which can serve as animal feeds and other agricultural uses and energy generation [3,4].  Brewery sludge as a fertilizer, which aid vegetation growth [5,6].  Brewery biomass as a biosorbents for the removal of heavy metal ions (Pb2+, Cu2+, Cd2+) from aqueous solution. In order to address the problem of improper treatment of brewery effluent, biological and technical treatments have previously been employed. However, the microbial treatment systems have advantage of being simple and low in cost [7]. Also, anaerobic digestion process treat brewery effluent without producing biological sludge and reduce COD, BOD, and TSS in the effluent with low hydraulic retention time [8]. The application of enzymes in the treatment of industrial waste water has been reported. The results show that there was large reduction in COD, BOD and TSS. This research is aimed at using enzymes such as carbohydrase, lipase, protease and mixed enzymes in the treatment of brewery effluent. 2.

Materials and methods

2.1 Sample collection 25-litre of brewery waste water was collected from a brewery in Benin City using plastic container. The enzymes (carbohydrase, lipase, and protease) were purchase from Sigma (Germany). All other chemicals used were of analytical grade and were obtained from the Chemical Engineering Laboratory store, University of Benin, Benin City. 2.2 Sample preparation Three litre of the brewery waste water was transferred each into 5-litre digestion flask. Solutions of 2.5g of carbohydrase, 2.5g of lipase, 2.5g of protease and 2.5g of mixed enzyme (1.25g carbohydrase and 1.25g lipase) was prepared and added to digestion flask 1, 2, 3 and 4 respectively. The control contains no enzyme but 2.5cm3 of distilled water. The test as well as the control were mixed and allowed for 96hrs. anaerobic fermentation period. Sample was taken from each digestion flask at an interval of 12hrs for physiochemical properties (COD, BOD, TSS, TDS, pH PO4 NH4 -N and THC) analysis. 2.3 Analysis of samples The physiochemical properties were analysed using APHA, [9] standard methods of analysis. 2.4 Statistical analysis The result of this study was analysed using analysis of variance (AOVA). 3.

Results and discussion

Figure 1 represents the variation of percentage reduction of COD with biodegradation time, in the presence of lipase, carbohydrase, protease, mixed enzyme (lipase + carbohydrase) and absence of enzyme (control). The results show that as the biodegradation time increased from zero to 96hrs., the percentage reduction of COD in the brewery wastewater increased from 1.2 – 72.0%, 20.1- 88.2%, 2.2 – 62.0%, 14.1- 90.0% and 0.6 – 6.9% for lipase, carbohydrase, protease, mixed enzyme and control respectively. These results correlate with that reported by World Bank, [8] Driessen and Vereijken [10] and Brito et al [11]. According to these researchers, the reduction of COD in the presence of enzymes is due to the fact that organic components present in the brewery wastewater are generally easily biodegraded by enzymes. However, the order of percentage reduction of COD for the enzyme systems is mixed enzyme > carbohydrase > lipase > protease. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1624 Innovations (15th – 17th April 2008), Benin City, Nigeria

Percentage reduction of COD (%)

100

80

60

40

20

0

0

20

40

60

80

100

Biodegradation time (hr) Lipase Protease Control

Carbohydrase Carhy. + Lipase

Fig 1: Variation of percentage reduction in COD with biodegradation time

Furthermore, it was observed that the enzyme free system (control) gave the lowest range of percentage reduction after 96hrs biodegradation period. This indicates that all the enzymes used in this work enhanced the rate of biodegradation of the materials (inorganic and organic) present in the brewery wastewater. Figure 2 shows the variation in the percentage reduction of BOD5 with biodegradation time, in the presence of lipase, carbohydrase, protease, mixed enzyme and control. The results show that the percentage reduction of BOD5 for lipase, carbohydrase, protease, mixed enzyme and control were in the range of 0.0 – 71.2%, 11.4 – 87.7%, 0.0 – 60.8%, 5.0 – 90% and 0.0 – 5.3% respectively. These results were similar to that reported by Driessen and Vereijken [10] and Brito et al [11]. The reason for this is the same as COD. The trend was also similar to that of COD. Moreover, as the biodegradation time increased, the percentage reductions for all the enzymes

Percentage reduction of BOD5 (%)

100 80 60 40 20 0 0

20

40

60

80

100

Biodegradation time (hr) Lipase Protease Control

Carbohydrase Carhy. + Lipase

Fig 2: Variation of percentage reduction in BOD5 with biodegradation time

systems increased rapidly, while the percentage reductions for the control show gradual increase. It is worthy to note that after 96hrs. biodegradation period, the mixed enzyme shows the highest enzyme activity in term of reduction of BOD5 in the brewery effluent, while the control gave the least percentage reduction. This is an indication that the substrate present in the brewery wastewater is composed mainly of lipid and carbohydrate materials as earlier reported pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1625 Innovations (15th – 17th April 2008), Benin City, Nigeria [10,11]. Hence the biodegradation rate of brewery wastewater was more enhanced by the presence of mixed enzyme (lipase and carbohydrase). Moreover, the order of percentage reduction of BOD5 was similar to that obtained for COD. Similar results were obtained for TSS, PO42-, NH4-N and THC as represented in Figures 3, 4, 5 and 6 respectively. The trends of these results agreed with that of BOD5 and COD. Hence the same explanation is applicable. However, the order of percentage reduction of the different physiochemical properties is THC > NH4-N > PO42- > COD > BOD > TSS.

Percentage reduction of TSS (%)

60 50 40 30 20 10 0 0

20

40

60

80

100

Biodegradation time (hr) Lipase Protease Control

Carbohydrase Carhy. + Lipase

Fig 3: Variation of percentage reduction in TSS with biodegradation time

Percentage reduction of PO4 (%)

100

80

60

40

20

0 0

20

40

60

80

100

Biodegradation time (hr) Lipase Protease Control

Carbohydrase Carhy. + Lipase

Fig 4: Variation of percentage reduction in PO4 with biodegradation time

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2nd International Conference On Engineering Research & Development: 1626 Innovations (15th – 17th April 2008), Benin City, Nigeria

Percentage reduction of NH4-N (%)

100

80

60

40

20

0 0

20

40

60

80

100

Biodegradation time (hr) Lipase Protease Control

Carbohydrase Carhy. + Lipase

Fig 5: Variation of percentage reduction in NH4-N with biodegradation time

This indicates that brewery wastewater contains large amount of organic compounds and little amount of suspended solids. Also the results obtained for all the physiochemical properties after 96hrs. enzyme treatment falls within the acceptable limit standard reported by FEPA [12] and WHO [13]. However, the results for enzyme free system (control) were above these limits. This indicates that only the enzyme treated brewery wastewater can be discharge into the surrounding environment after 96hrs of treatment. However, the results of the variation of percentage reduction of NH4–N with biodegradation time were slightly different as shown in Figure 6. As a result, the order of percentage reduction of NH4-N was mixed enzyme > lipase > protease > carbohydrase > control. This change in order is consistent with the affinity each enzyme has for NH4-N [14].

Percentage reduction of THC (%)

100

80

60

40

20

0 0

20

40

60

80

100

Biodegradation time (hr) Lipase Protease Control

Carbohydrase Carhy. + Lipase

Fig 6: Variation of percentage reduction in THC with biodegradation time

4.

Conclusions pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1627 Innovations (15th – 17th April 2008), Benin City, Nigeria The following conclusions can be drawn from this study:  the brewery effluent is composed mainly of organic materials that are biodegradable,  bio-catalyst (enzyme) such as carbohydrase, protease, lipase and mixed enzyme can suitably be used in the bio-treatment of brewery wastewater,  the enzymatic treatment of brewery effluent gave satisfactory results, in that the values of the concentration of the physiochemical properties were all within the FEPA’S and WHO’S acceptable limit standard and meet discharge requirements,  the order of enzyme activity on the physiochemical parameters was mixed enzyme > carbohydrase > lipase > protease > control,  The enzyme free system (control) produced treated brewery effluent with the concentrations of the physiochemical properties above the minimum acceptable limit of FEPA and WHO standard after 96hrs of biodegradation.

References [1] C. Genner “Treatment and disposal of brewery effluents” Brewers Guardian, (1988), 25-17. [2] R. Mulder and P. M. J. Bruijn Treatment of brewery waste water in a (denitrifying) CIRCOX airlift reactor proceeding of the 2nd IWA International specialized Conference on Biofilm reactors, Paris, France, (1993). [3] K. Kanagachandran. “Biogas generation from brewery wastes”. Demonstration at a laboratory scale. Tech. Q. Master Brew. Assoc. Am., (2004), 41(4), 394-397. [4] K. Kanagachandran. “Optimisation of spent grain slurry for energy generation”. Tech. Q. Master Brew. Assoc. Am., 42(4), 324-328 (2005). [5] O. Luque, O. Bracho and T. W. Maier. “Utilization of brewery waste water sludge for soil improvement. Tech. Q. Master Brew. Assoc. Am., 27 (1), 5-9, (1990). [6] C. Stocks, A. J. Barker and S. Guy “The composting of brewery sludge”. J. Inst. Brew., 108(4), 452-458, (2002). [7] G. R. Zoutberg and R. Franklin, “Anaerobic Treatment of Chemical and Brewery Wastewater with a new type of anaerobic reactor; the biobed EGSB Reactor”. Waterscience and Technology 34(5-6) 375-381. (1996) [8] World bank “Industrial pollution prevention and abatement: Breweries, Draft Technical background document. Environment Department, Washington D.C. (1998) [9] APHA Standard methods for the examination of water and wastewater. American Public Health Association. 19th Edition. (1995). [10] W. Driessen and T. Verijken. “Recent development in biological treatment of brewery effluent”, The Ins. and guild of brewery convention, Zambia, (2003). [11] A. G. Brito, A. C. Rodrigues and L. F. Melo “Feasibility of a pulsed sequencing batch reactor with anaerobic aggregated biomass for the treatment of low strength wastewaters, Water Sci. Technol. 35(1): 193 (1997). [12] Federal Environmental Protection Agency (FEPA) “Guidelines and 87-95.

standard for Environmental Impact Assessment in Nigeria” (1997), pp

[13] World Health Organization (WHO) “Guidelines for drinking water quality”, 2nd Edition, Vol. 2. Criteria and other supporting information. Geneva. (1984) , pp. 121-131. pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA

2nd International Conference On Engineering Research & Development: 1628 Innovations (15th – 17th April 2008), Benin City, Nigeria

pdfMachine - is a pdf writer that produces quality PDF files with ease! Get yours now! “Thank you very much! I can use Acrobat Distiller or the Acrobat PDFWriter but I consider your product a lot easier to use and much preferable to Adobe's" A.Sarras - USA