BOOK of ABSTRACTS

BALKAN PHYSICAL UNION &

HELLENIC PHYSICAL SOCIETY

7th GENERAL CONFERENCE OF THE BALKAN PHYSICAL UNION Alexandroupolis 9-13 September 2009

BOOK of ABSTRACTS

With the cooperation of THE PHYSICS DEPARTMENTS OF THE UNIVERSITIES OF ATHENS,CRETE, IOANNINA,PATRAS, THESSALONIKI and the PERFECTURE OF EVROS, MUNICIPALITY OF ALEXANDROUPOLIS LOCAL UNION OF MUNICIPALITIES & COMMUNITIES OF EVROS

E.E.º.

BALKAN PHYSICAL UNION &

HELLENIC PHYSICAL SOCIETY

7th GENERAL CONFERENCE OF THE BALKAN PHYSICAL UNION Alexandroupolis 9-13 September 2009

BOOK of ABSTRACTS

With the cooperation of THE PHYSICS DEPARTMENTS OF THE UNIVERSITIES OF ATHENS, CRETE, IOANNINA, PATRAS, THESSALONIKI and the PERFECTURE OF EVROS, MUNICIPALITY OF ALEXANDROUPOLIS LOCAL UNION OF MUNICIPALITIES & COMMUNITIES OF EVROS

E.E.º.

2

Scientific Committee Metin Arik, Professor, President of BPU Baki Akkus, Professor, President of the Turkish Physical Society Turkey Yesim Oktem, Professor, Istanbul University Dr. Aleksandar Belic, President of Serbian Physical Society, Serbia Milan Damnjanovic, Professor, University of Belgrade, Serbia Angelos Angelopoulos, Associate professor, President of Hellenic Physical Society Kostas Chelmis, Associate professor, President of Physics Dpt of Athens University Ilias koutsikos, Greece Eleftherios Economou, Professor Emeritus, Physics Dpt of the University of Crete Panagiotis Sandilos, Professor, University of Athens Pellumb Berberi, Professor, President of Physical Society of Albania Fatos Ylli, Professor, Albania Matey Mateev, Professor, President of the Bulgarian Physical Society Alexander Petrov, Professor, Bulgaria Stergios Logothetidis, Professor, President of Physics Dpt. of Thessaloniki University, Greece Konstantinos Kosmidis, Professor, President of Physics Dpt. of Ioannina University, Greece Christoforos Krontiras, Associate professor, President of Physics Dpt of Patras University Yesim Oktem, Professor, Istanbul University Victor Ciupina, Professor, Romania

International organizing Committee Goran Djordjevic, Professor, University of Nis Dr. Darko Tanaskovic, Secretary of Serbian Physical Society Athanasios Labros, Executive secretary of BPU Martha Spyropoulou, Associate professor, Physics Dpt. University of Athens Stavros Ioannou, Cyprus Antoneta Deda, Prof., Albania Dritan Spahiu, Albania Panos Kokkas, Associate professor, Physics Dpt. University of Ioannina Konstantinos Chrysafis, Assistant professor, Physics Dpt. University of Thessaloniki Dimitris Karabourniotis, Associate professor, Physics Dpt. University of Crete Athanasios Argyriou, Assistant professor, Physics Dpt. University of Patras Ela Ganioglou, Istanbul University Alexandru Calboreanu, Prof., Romania

LOCAL Organizing Committee Nikolaos Rigopoulos Chrisa Aleksoudi Panagiotis Fildisis Nektaria Adaktylou Dimitris Angelidis Georgios Angelidis Melina Adamidou Kostas Koukoulas Panagiota Martini Niki Hagikiriakou Maria Lagou Georgios Zafirakidis

Antoniou Panagiotis Gemousakakis Triantafillos Zapartas Emmanouil Sitsanlis Ilias Deliakidis Panagiotis Xatzidis Anastasios Zapartas Panagiotis Tsoukala Aristea Mpantas Nikolaos Limperopoulou Georgia Pantidis Konstantinos Hagiioakimidis Anestis

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INVITED TALKS THE PHYSICS OF ENERGY TECHNOLOGIES F. Wagner Max-Planck Institut für Plasmaphysik Teilinstitut Greifswald, EURATOM Association Abstract: We are all aware that energy is gradually getting a rare commodity on one side and that the consequences of burning fossil fuels may lead to major changes of our climate. Physics plays a crucial role in the improvement of established energy technologies but also in the development of new sources. Electricity is the highest form of energy in a technical context and plays a specific role in the operation of our economies and societies. In my report, I will introduce with the electricity supply situation in Europe. I will try to elucidate the role physics can play in photo voltaic systems, in saving measures, in nuclear fission and in nuclear fusion. Photo voltaic systems develop toward higher efficiency, the use of lower-cost materials and the better integration in the existing periphery are major development steps. The application of microelectronic technology and the use of electricity allow saving energy in many areas, housing being possibly the most effective one. Fission develops the Generation IV systems with higher safety, other fuels like Thorium and with concepts to transmute fissile material. Fusion does the step now to the first fusion reactor, ITER, to be built in France.

THE GREENHOUSE GAS REGIONAL INVENTORY PROTOCOL Rainer Scheppelmann International Climate Cooperation In a 36-month project, 18 european metropolitan regions aim to devise strategies for achieving an 80% reduction of greenhouse gases emissions by the year 2050. Lead partner and Coordinator is the Metropolitan Region of Hamburg. Scientific monitoring is provided by the University of Manchester, which devised the GRIP model – the Greenhouse gas Regional Inventory Protocol. Project EUCO2 80/50 is a three-step mitigation project for Metropolitan Areas. After the production of regional greenhouse gas inventories, political and economic stakeholders come together in scenario/strategy workshops in order to find a consensual long term CO2 reduction strategy. Results will be disseminated to other metropolitan areas. The discussion on the reduction of greenhouse gases shows ever more clearly that it’s not a problem of lacking solutions. By higher energy-efficiency in production, by energy-saving in transport and buildings and by use of renewable energies, the reduction goals of the EU can be achieved. The main problem rather consists in implementing the measures that have been identified as good practices into tangible politics. Therefore we need a decision finding process that unshackles the issue from ideological dispute and guides the stakeholders of economy, politics, science and administration towards a consensual strategy. Exactly this is the task and goal of project EUCO2 80/50.

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CARBON BASED NANOSTRUCTURES SYNTHESIS AND CHARACTERIZATION V. CIUPINA University of Constanta, Mamaia Avenue 124, Constanta, 900527, ROMANIA ABSTRACT Carbon based nanostructures are of considerable interest for application in nanotechnologies related fields such as medicine, electronics, catalysis, environment, glasses etc. Typical carbon based nanostructures methodologies involving different routes are presented (thin films vapor deposition procedures, iron-carbon nanostructures laser pyrolysis, catalyzed iron carbon nanoparticles nanotubes, etc.). The characterization of carbon based nanostructures has been made by transmission electron microscopy and selected area diffraction procedures, X-ray analysis, Mossebaur spectroscopy, electron energy loss spectroscopy and Auger spectroscopy.

ENERGY AND ENVIRONMENT IN URBAN AREAS By Prof. D.N.Asimakopoulos Cities are increasingly expanding their boundaries and populations. From the climatological point of view, human history is the history of urbanization. Recent industrialization and urbanization have affected dramatically the number of the urban buildings with major effects on their energy consumption. It is expected that 700 million people will move to urban areas in the next decade. The number of urban dwellers has risen from 600 million in 1950 to 2 billion in 1986 and if this growth continues, more than one - half of the world’s population will live in cities by the end of this century, where 100 years ago, only 14 percent lived in cities and in 1950, less than 30 per cent of the world population was urban. Estimations show that urban populations will occupy 80 % of the total world population in 2100. Today, at least 170 cities support more than one million inhabitants each. As estimated, in the United States, 90 percent of the population is expected to be living in, or around, urban areas by the year 2010. Urbanization leads to a very high increase of energy use. An 1 % increase in the per capita GNP leads to an equal (1.03), increase in energy consumption. However, an increase of the urban population by 1 % increases the energy consumption by 2.2 %, i.e., the rate of change in energy use is twice the rate of change in urbanization. Comparison of the energy consumption per capita for the inner and outer parts of selected cities shows that the consumption in the inner part is considerably higher. As an example the inner London presents 30 % higher energy consumption per capita than the outer part of the city. What should be done to improve the urban environment and to reduce the energy consumption? ● Improve the quality of the construction of urban buildings ● Development of efficient codes and legislation for all constructions ● Introduction of energy efficiency technologies in retrofitting of buildings ● Appropriate solutions to decrease the penetration of air conditioning ● Improvement of the ambient microclimate in cities using more appropriate materials, green areas, cool sinks for heat dissipation, appropriate layout of urban canopies, etc., to counterbalance the effects of temperature increase. The existing knowledge is continuously improving, however a more scientific than empirical approach has to be employed. Future research actions are absolutely necessary and should focus on the better understanding of the urban climatology as well as on the development of appropriate materials - technologies and integration techniques for urban buildings.

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FRONTIERS OF R & D IN PHOTOVOLTAIC MATERIALS AND DEVICES Sener Oktik Mugla University Clean Energy Resources R&D Centre 48000 Mugla Turkey, [email protected], Tel: +90 252 223 92 67 The current total world installed power capacity for electricity production is around 4000GW. In recent years dramatic advances in PV technology combined with environmental concerns have resulted in a significant growth in manufacturing output in the PV value chain and consequently in the related markets. By the end of 2008 the accumulated global PV capacity has reached to 15GWp contributing less that 0.4% to the total world capacity. The opportunities for Photovoltaic Power Systems having a larger share in the world energy mix in the near future do exist if targets in R&D of PV materials and devices are met in time. In this work frontiers of basic, applied as well as industrial research and development activities in materials science and engineering for PV materials and devices together with processing technologies will be reviewed. Topics such as; siliconbased single-crystal and thin-film photovoltaic devices, organic-and hybrid-based photovoltaic structures, compoundsemiconductor-based photovoltaic devices, nano-structured photovoltaic devices, dye sensitized solar cells will be covered. Special emphasis will be given to the priority R&D areas listed by “The European Photovoltaic Technology Platform” in the “Strategic Research Agenda for Photovoltaic Solar Energy Conversion” and it’s “Implementation Plan”.

CC CALCULATIONS ON SOME NUCLEI WITH SRM N. T. Okumsoglu 1 , F. Korkmaz Gorur

1,R.

Keser 1, E. Sh. Soukhovitskii

1Department

2

and S. Chiba

3

of Physics, Faculty of Art and Science, Rize University, Rize, 53100, Turkey Institute for Energy and Nuclear Research, 220109, Minsk-Sosny, Belarus 3 Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195, Japan ABSTRACT Coupled-channels (CC) optical model is an effective and powerful method for prediction of nucleon-nuclear optical interaction cross sections, simultaneously providing transmission coefficients to enter statistical models for calculations of various inelastic and reaction cross sections. Furthermore nucleon wave functions to be used in calculations of matrix elements for quantum-mechanical models of nuclear reactions, e.g., for DWBA, are also supplied. Recent requests on evaluated nuclear data from various applications expanding list of nuclides and interacting nucleon energy can be only satisfied by utilizing coupled -channels optical model codes with realistic coupling and sophisticated optical model potential (OMP). Reliability of CC predictions, neglecting numerical accuracy of the computational algorithms, is determined by two issues: the coupling scheme and optical potential used. Standard CC options are based on rather simple coupling schemes like rigid rotator or axial vibrator nuclear models, while experimental low-lying collective levels show that nuclear excitations have more rich and complicated nature. Soft-rotator nuclear model (SRM) allows description of low-lying collective levels of different rotational-vibrational nature. It considers nucleus to be non-axially deformed and soft so that nuclear shapes oscillate around equilibrium deformations and non-axialities. Latest versions of the model take into account the non-axial quadrupole, octupole and hexadecapole deformations, and ‚ 2, ‚3 and Á-vibrations with account of nuclear volume conservation. The model accounts for the stretching of the soft nucleus while rotating due to centrifugal forces, so that equilibrium deformations for collective levels with higher spins are increased comparing with the ground states deformations and also the stretching increases. Softrotator nuclear Hamiltonian parameters and thus nuclear wave functions are determined analyzing the experimental collective level structure, which is available for most of the isotopes. Such Hamiltonian parameters expose systematic trend, which can be used in case when the detailed experimental level scheme is unavailable. Model allows rather accurate description of low-lying collective levels for the first four-five rotational bands, including negative parity band. Coupledchannels optical model with realistic and saturated coupling built on soft-rotator nuclear wave functions (contrary to simpler nuclear structure models) describes enough coupled levels, therefore the coupling of additional levels changes reaction cross-sections within experimental errors. In other words, the effect of unaccounted levels is negligible and our coupling is saturated. This method had been successfully applied to heavy rotational, light nuclei like ÅÇC and Ç8Si, and also to vibrational medium-mass nuclei such as 40Ar, 52Cr, 56Fe and 58Ni. The soft-rotator model also predicts E2, E3, E4 Átransition probabilities, in a self-consistent manner, which makes results of optical model analyses more reliable. Before we used standard energy-dependent polynomial functional to describe potential depths. Such OMP must be 2Joint

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derived as a result of best-fit description of all available regional experimental data, allowing reliable prediction of the data for isotopes measurements for which are unavailable or not reliable. It is clear that OMP with polynomial dependencies is not very good for interpolation and especially for the extrapolation of the result to different incident energy regions for which optical experimental data is unavailable or scarce. On the other side the OMP accounting for dispersive relationships between its imaginary and real part is expected to give more reliable results. Additionally, dispersive potentials have less adjustable parameters than conventional nondispersive potentials and those parameters are often energy-independent. Especially important is the possibility to derive energy-independent nuclear form-factor geometry. In this work, we propose dispersive Lane-consistent optical potential form and demonstrate its application to analyses of experimental optical data for nuclides from different A-mass regions. This activity is based on using coupled-channels optical model code OPTMAN, the new version of which already incorporates those new findings.

CRITICAL PHENOMENA AND FINITE-SIZE SCALING CRITICAL BEHAVIOR OF CONFINED SYSTEMS N. S. Tonchev Institute of Solid State Physics, Bulgarian Academy of Science, 1784 Sofia, Bulgaria ABSTRACT In experiment, samples are always of finite size and have confined geometry. In theory, critical behavior in its literal sense takes place for an infinite system at which the volume has become infinite at constant particle density in the bulk. Only in the infinite size limit critical point, which is a hallmark of systems undergoing phase transition, is characterized mathematically by singularities in the thermodynamic functions. To what extent an experimental sample can be regarded in the theory as bulk or finite size, depends on the ratio y = Í / L where Í is correlation length and L is the effective value of the linear extensions of the system. If y 30∞) angles to the planetary spin axis, and substantial magnetospheres with strong electron and ion intensities. Following the encounter with Neptune Voyager 2 was directed south of the ecliptic plane, also on escape trajectory. The Voyager Interstellar Mission continues to this day, and data from ~ 109 AU and ~ 90 AU from Voyager 1 and 2, respectively, are received daily. So far, Voyager 1 has crossed the heliospheric Termination Shock (TS) at ~ 94.0 AU on December 16, 2004, while Voyager 2 crossed the same TS but at southern latitudes at ~83.65 AU on August 28, 2007. The entry of both spacecraft into the heliosheath was marked by sharp increases in energetic ions (> 30 keV), modest increases in the strength of the interplanetary magnetic field (IMF) and sharp decreases in the velocity of the solar wind. However, the theoretically expected maximum of anomalous cosmic rays (ACR) at the TS did not materialize, and the diffusion-convection model of acceleration at the shock was discredited. Other surprises included the transfer of the directed energy of the solar wind to the acceleration of energetic particles rather than the heating of the plasma, as theory had predicted, and the observation of a nearly universal energy dependence of the particle spectrum in the form dj/dE= k E-1.5 . The near-equality of the heliosheath particle fluxes over the past several years at both Voyagers, even though they are separated by over 100 AU, and the anisotropy of the flow are principal characteristics of the medium that can be used to infer the width of this region and predict the entry of Voyager into true interstellar space.

NOVEL PROCESSES IN MATER-WAVE OPTICS Martial Ducloy Laboratoire de Physique des Lasers, CNRS and Institut Galilée Université Paris 13, 93430-Villetaneuse, France At the cross-over between several domains of science and technology, matter-wave optics is the field dealing with the generation and analysis of coherent matter waves. Owing to the recent development of atom cooling techniques and material nanostructure fabrication, this field, as well as atom interferometry and its applications, has quickly grown. Many of the functions previously operated in light optics have been realised in atom optics: atom diffraction and reflection, beam splitters, etc. The physical processes to implement those functions in matter-wave optics will be discussed, as well as their specific characteristics originating in the specific properties of the associated particle: nonzero mass, vacuum dispersion for the “de Broglie” wave, scalar character of the wave, internal atomic degrees of freedom, 10

intrinsic polarisability, etc. Along this viewpoint, novel concepts in the field of matter-wave optics will be described, including atom interferometry at the nano-scale, non-diffracting atom waves and negative-index media (“meta-materials”) for matter-wave optics. Their distinct properties (atom beam profile, group velocity characteristics, wave-packet dynamics, matter-wave’s propagation…) will be analysed, comparatively to the equivalent processes in photon optics. References: J. Grucker et al, “Schlieren imaging of nanoscale atom-surface inelastic transition using a Fresnel biprism atom interferometer”, Eur. Phys. J. D 47, 427 (2008) F. Perales et al, “Ultra thin coherent atom beam by Stern-Gerlach interferometry”, Europhys. Lett. 78, 60003 (2007) J. Baudon et al, “Negative-index media for matter-wave optics”, Phys. Rev. Lett. 102, 140403 (2009)

ENTROPY, A UNIFYING CONCER Constantinos Tsallis Centro Brasileiro de Pesquisas Fisicas, Brazil ABSTRACT Entropy, even more than energy, is a unifying concept. Energy constitutes a central concept in mechanical (classical, quantum, relativistic) systems, with important applications in physical, chemical, biological systems. The concept of entropy is even broader, since it concerns a vast class of phenomena, conservative or dissipative, in natural, artificial and social sciences. The current status of research in this area, focusing very especially on complex systems, will be briefly presented, as well as some interdisciplinary applications. Bibliography: (i) M. Gell-Mann and C. Tsallis, Nonextensive Entropy - Interdisciplinary Applications (Oxford University Press, New York, 2004); (ii) J.P. Boon and C. Tsallis, Nonextensive Statistical Mechanics - New Trends, New Perspectives, Europhysics News 36 (6) (European Physical Society, 2005); (iii) C. Tsallis, Introduction to Nonextensive Statistical Mechanics - Approaching a Complex World (Springer, New York, 2009); (iv) C. Tsallis, Entropy, Springer Encyclopedia of Complexity and Systems Science (2009); (v) http://tsallis.cat.cbpf.br/biblio.htm

INFLUENCE OF COLLISIONS WITH CHARGED PARTICLES ON ASTRONOMICAL SPECTRA Milan S. Dimitrijevié Astronomical Observatory, Volgina 7, 11060 Belgrade, Serbia ABSTRACT Broadening of spectral lines by collisions with charged particles - Stark broadening is considered and analyzed here, in particular from the aspect of stellar spectra analysis and synthesis. This line broadening mechanism is of interest e.g. for the research of white dwarfs and hot stars of A and B type, especially chemically peculiar stars. Even in cooler star atmospheres as e.g. Solar one, Stark broadening may be important. For example, the influence of Stark broadening within a spectral series increases with the increase of the principal quantum number of the upper level and consequently, Stark broadening contribution may become significant even for the Rydberg lines in the Solar spectrum. This broadening mechanism, influencing line shapes in astronomical spectra, is of significance also for the research of neutron stars and the investigation of radio recombination lines from molecular and ionized hydrogen clouds. Line shapes enter in the models of radiative envelopes by the estimation of the quantities such as absorption coefficient, Rosseland optical depth and the total opacity cross-section per atom, so that the corresponding Stark broadening parameters are needed for the determination of these quantities for stellar plasma conditions when this broadening mechanism cannot be neglected. Stark broadening parameters are needed as well for the determination of the chemical composition of stellar atmospheres i.e. for stellar elemental abundances determination from equivalent widths of absorption lines, estimation of the radiative transfer through the stellar plasmas, especially in subphotospheric layers, and for opacity calculations. radiative acceleration considerations, nucleosynthesis research and other astrophysical topics. For the estimation of radiative transfer through stellar plasmas, especially in subphotospheric layers as well as for the determination of chemical abundances of elements from equivalent widths of absorption lines, an as much as possible 11

complete set of Stark broadening data for an as much as possible larger number of spectral lines for different emitters is needed, since we do not know a priori the chemical composition of a star. Consequently, it is obvious that stellar spectroscopy depends on very extensive list of elements and line transitions with their atomic and line broadening parameters. Need for the broadening data for a large number of spectral lines for trace elements and their singly and multiply charged ions is additionally stimulated by the development of space astronomy, since with instruments like Goddard High Resolution Spectrograph (GHRS) on Hubble Space Telescope, an extensive amount of high quality spectroscopic information has been and will be collected, stimulating the spectral line shape research. Development of computers also stimulates the need for a large amount of atomic and spectroscopic data. Particularly large number of data is needed for example for opacity calculations and modeling of stellar atmospheres. For example, PHOENIX computer code for the stellar modeling includes a permanently growing database containing atomic and molecular data for several hundred millions transitions. Results of Stark broadening research are not interesting for modeling, analysis and investigation of stellar plasma, but also for diagnostics and research of laboratory plasma, as well as fusion, laser produced and technological plasmas. We will review and discuss also the results of Stark broadening study in Serbia, relevant to astrophysical problems. Particular attention will be paid to the results obtained within the semiclassical-perturbation and modified semiempirical methods as well as to the astrophysical aspects of research and the use in astrophysics of results and achievements in Stark broadening investigations of Serbian astronomers and physicists.

TURKISH ACCELERATOR CENTER (TAC) PROJECT STATUS AND REGIONAL IMPORTANCE Ö. Yava{* Ankara University, Fac. of Eng., Dept. of Eng. of Physics, 06100, Tandogan, Ankara, Turkey ABSTRACT Turkish Accelerator Center (TAC) Project has started in 1997 with support of State Planning Organization (SPO) of Turkey under coordination of Ankara University. After completing Feasibility Report (FR, 2000) and Conceptual Design Repot (CDR, 2005), third phase of project is started in 2006 as an inter-universities project with support of SPO. Third phase of project has two main scientific goals: to write Technical Design Report (TDR) of TAC and to establish an Infrared Free Electron Laser (IR FEL) facility as a first step. TAC collaboration include ten Turkish Universities: Ankara, Gazi, _stanbul, Bo_aziçi, Do_u_, Uluda_, Dumlup_nar, Ni_de, Erciyes and S. Demirel Universities. It is planned that the first facility will be an IR FEL & Bremsstrahlung facility based on 15-40 MeV electron linac and two optical cavities with 2.5 and 9 cm undulator magnets to scan 2-250 microns wavelength range. Main purpose of facility is to use IR FEL for research in material science, nonlinear optics, semiconductors, biotechnology, medicine and photochemical processes. In this study, aims, regional importance, main parts and main parameters of TAC and TAC IR FEL & Bremsstrahlung projects are explained. Road map of TAC project is given. National and international collaborations are explained. The first facility and TDR studies are planned to be completed in 2012. Construction phase of TAC will cower 2013-2023. *for TAC Collaboration (http://thm.ankara.edu.tr).

TITANIA NANOSTRUCTURES FROM FIRST-PRINCIPLES CALCULATIONS FOR PHOTOCATALYTIC AND PHOTOVOLTAIC APPLICATIONS Oñuz Gülseren Bilkent University, Department of Physics, Bilkent, 06800 Ankara, Turkey We have systematically investigated structural, electronic and magnetic properties of various TiO nanostructures such as small (TiO2)n (n=1-10) clusters, very thin TiOx (x=1,2) nanowires as well as bulk-like (110) rutile nanowires and anatase surfaces by using the first—principles plane wave pseudopotential calculations based on density functional theory. A large number of different possible structures have been searched via total energy calculations in order to find the ground state structures of these nanostructures. In general, ground state structures of TiO2 nanoclusters have at least one dangling or pendant O atom. Only lowest lying structure of n=10 cluster does not have any pendant O atom. In ground state structures, Ti atoms are at least 4—fold 12

coordinated for n > 4. Clusters prefer to form three dimensional and compact structures. Formation energy increases with the size of cluster. All clusters have singlet ground state. Interaction of ground state structure of each (TiO2)n clusters with H2O and various transition metal (TM) atoms like V, Co and Pt also have been investigated. All these elements interact with clusters forming strong chemisorption bonds, and permanent magnetic moment is induced upon the adsorption of Co or V atoms. Similarly, the stability of TiOx nanowires enhances with its increasing radius, thus reaching sufficient coordination number of Ti and O atoms. Three dimensional structures are more energetic than planar ones for both of the stoichiometries. All stoichiometric TiO2 nanowires studied exhibit semiconducting behavior and have nonmagnetic ground state. In TiO nanowires, both metallic and semiconductor nanowires are resulted. In this case, in addition to paramagnetic TiO nanowires, there are also ferromagnetic ones. In addition, there is a correlation between binding energy (Eb) and energy band gap (Eg) of TiO2 nanowires. In general, Eb increases with increasing Eg. We have also studied the structural and electronic properties of bulk-like rutile (110) nanowires. There is a crossover in terms of energetics, and bulk-like nanowires are more stable than the thin nanowires for larger radius wires after a critical diameter. These (110) rutile nanowires are all semiconductors. Last, we systematically investigated the interaction of perylenediimide (PDI)-based dye compounds (BrPDI, BrGly, and BrAsp) with both unreconstructed (UR) and reconstructed (RC) anatase TiO2 (001) surfaces. All dye molecules form strong chemical bonds with surface in the most favorable adsorption structures. In UR—BrGly, RC—BrGly and RC—BrAsp cases, we have observed that HOMO and LUMO levels of molecules appear within band gap and conduction band region, respectively. Moreover, we have obtained a gap narrowing upon adsorption of BrPDI on the RC surface. Because of the reduction in effective band gap of surface—dye system and possibly achieving the visible light activity, these results are valuable for photovoltaic and photocatalytic applications.

THERMOELECTRIC MATERIALS AND APPLICATIONS ON THE RECOVERY OF WASTE HEAT ENERGY Theodora Kyratsi Department of Mechanical and Manufacturing Engineering University of Cyprus, 1678 Nicosia, CYPRUS Email: [email protected] In almost every case during production, storage and utilization of energy, large amounts are lost as waste energy. Recovering this waste energy is nowadays a challenge when energy is one of the most important global problems that we need to face. Modern technology on thermoelectrics (TE) offers a solution based on the conversion of the heat back into useable electricity through Seebeck effect. In the last decades subjects related to this technology have attracted a great interest and the applications involve various systems mainly in transportation and industrial sector. The advantages of TE applications include, among others, features such as no moving parts, simple configuration and long-run unattended operation. Research on high temperature TE materials, 800K or above, include different systems such as chalcogenides, skutterudites, oxides, Si&Ge-based. Selected materials have ZT values up to 1, while research has, already, shown higher ZT values, of about 2, using nanostructured materials. Since, commercially-used TE modules are mostly Bi2Te3-based, which limits their temperature range at about 500-550K, the efforts are mainly focused on materials with high thermoelectric performance at higher temperatures. Our research focuses on chalcogenide compounds with promising TE properties. In alkali bismuth chalcogenide compounds, the alkali metals tend to create structural complexity in the crystal, which in turn can lead to complex electronic structure, high Seebeck coefficient and low thermal conductivity. Powder techniques, based on mechanical alloying and sintering process, are applied in order to prepare nanocrystalline materials of such complex chalcogenides as well as of PbTe-based systems. In both systems, such techniques are applied aiming to fabricate nanocomposite materials with improved properties.

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HISTORY OF PHYSICS - A CHALLENGE TO THE PHYSICS COMMYNITY Peter Maria Schuster Chair, History of Physics Group, European Physical Society The request to us physicists to become eventually conscious of ‘our‘ past is getting of a crucial importance. However, the heritage of our European physics does not only survive through scientific data and research reports, but also through the biography of the scientists, moreover, through historical scientific instruments. It is therefore essential that the physicists from every European nation eventually assume themselves the task to work up their national history of physics and that they help preserve the historical instruments, which once served their heroes of physics. The European Physical Society (EPS) is supporting these efforts and will open under the direction and administration by the Victor F. Hess Society a European Centre for History of Physics in Styria at Poellau Castle, in the heart of Austria. There, starting from May 2010, the EU member States ‘from the core and the fringe‘ will alternately expose the highlights of their national History of Physics.

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A NUCLEAR PHYSICS A COMPREHENSIVE STUDY ON NATURAL GAMMA RADIOACTIVITY LEVELS AND ASSOCIATED DOSE RATES FROM SANDS AND ROCKS IN RIZE, TURKEY R. KESER 1, N.T. OKUMUSOÒLU 1, I. ALP 2 and F.K. GÖRÜR 1 1 Department of Physics, Faculty of Arts and Sciences, Rize University, Rize, TURKEY 2 Department of Mining Engineering, Faculty of Engineering, Karadeniz Technical University, Trabzon, TURKEY

ABSTRACT A study was done to determine activity concentration levels and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K, in sand samples along the coast of Rize and some geologicalformations of Rize, by means of high-resolution gamma rayspectrometry. A total of 154 representative sand and 18 rock samples werecollected from all over the region. To assess the radiological hazard of the natural radioactivity, the radium equivalent activity, and the absorbed dose rate were calculated. Some parameters such as grain size and mineral content were also studied in connection with the distribution of 232Th, 238U and 40K in the region. The sand samples were cleaned with warm water, dried and subjected to light and heavy mineral separation using bromoform (tri-bromo-methan, Ú=2.89). The heavy mineral concentrates were then separated into different individual mineral fractions with a magnetic separator. In grain size study, samples were sieved after drying into five classes of particle size, namely 0.65) which happens rarely in common practice (e.g. for copper vapor lasers). Taking into account that the central peak energy is confined within a smaller spot area, the net impact of side energy spread diminishes furthermore. 7. 1. J. W. Goodman, Introduction to Fourier Optics, McGraw-Hill, 1996

DEPENDENCE OF RADIATION DAMPING ON THE FRACTION OF WATER IN H2O/D2O MIXTURE MEASURED BY 400MHz NMR Yaliknkiliç S and Yilmaz A Department of Physics, University of Dicle, 21280 Diyarbakir Turkey ABSTRACT All Inversion Recovery measurements on samples containing significant amounts of water protons suffer from the effect of radiation damping caused by a strong coupling between high proton magnetization and the RF coil. Determination of the dependence of the radiation damping on fraction of water may be useful for measuring relaiable relaxation times. In this work, H2O/D2O mixtures containing various fractions of water were prepared. The fraction of water in these samples were changed from 0.0 to 0.3. The experiments were carried out on a BRUKER AVANCE-NMR spectrometer operating at 400 MHz. .Successive recovery signals were obtained versus a set of delay times, while successive SE decays were obtained versus a set of echo times. Spin-lattice(T 1) and Spin-spin(T2) relaxation times of H2O/D2O mixtures were also measured by IR and GPMG methods. Data shows that the radiation damping increases as water fraction increases. The relaxation times of the mixtures containing fractions of 0.0, 0.05 and 0.1 are gradually influenced by radiation damping. The radiation damping dominates whole relaxation for the mixtures containing fractions of 0.2 and more water. The radiation damping decreases upon addition of protein. Present data suggest that the relaxation of samples containing water up to 10% can reliably be measured by IR and GPMG.

THIN DIELECTRIC FILMS CONTAINING Tb 3+ IONS FOR APPLICATION IN THIN FILM SOLAR CELLS M. Sendova-Vassileva 1, K. Baumgartner

2

O. Angelov 1 , D. Dimova-Malinovska 1, R. Carius

2

1CL

SENES, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia, Bulgaria; e-mail: [email protected] 2Institut für Energieforschung 5, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany ABSTRACT Thin transparent dielectric films containing Tb3+ are developed for application as spectral converters of the solar spectrum in thin film silicon solar cells. Solar cells with glass on the front side have e.g. a poor blue and UV response due to absorption in the glass and contact layers. These spectral converters with absorption bands situated between 200 and 400 nm shall be deposited on top of the glass. Their emission bands in the region 400 - 600 nm are well suited for the spectral 80

response of thin film silicon solar cells. Here, the results on the deposition and characterization of thin SiO2 and Al2O3 films containing Tb3+ ions are presented. The films are prepared by RF magnetron co-sputtering, a well established technique for large areas. Tb doped SiO 2 and Al2O3 films sputtered in Ar or Ar + O2 atmosphere were investigated in order to study the influence of the different optical properties of the host material on the conversion efficiency. Tb pieces of different areas were placed inside the erosion zone of the target. Silica and polished Si substrates were used which were not intentionally heated. The area of the Tb pieces (and the corresponding Tb concentration) and the O2 partial pressure in the plasma, PO2 (and corresponding environment of the Tb3+ ions in the host material) were varied. To study the optical properties of the thin films it is not necessary to excite the Tb3+ ions with UV light, because excitation of the Tb3+ ions resonantly from the ground state (7F6) into the 5D4 level (~ 488 nm) provides the required information. Photoluminescence (PL) was measured at room temperature, using the 488 nm line of an Ar laser and a nitrogen-cooled CCD camera attached to a monochromator. The dependence of the PL intensity at the maximum of the 542 nm band (5D4 – 7F5 transition) in the films on the deposition parameters and the concentration of the Tb ions in the film was studied in order to assess the suitability of these films for the down conversion and to optimize the deposition conditions. It was found that the intensity exhibits a maximum at about 1 at.% Tb in the film for both dielectric matrices. At higher Tb content concentration quenching sets in. In the case of SiO2:Tb the addition of oxygen in the sputtering atmosphere did not lead to an increase of the PL intensity. Annealing studies were performed on SiO2:Tb with two different methods to improve the PL intensity: (i) in vacuum for 30 minutes and (ii) by rapid thermal annealing (RTA) in nitrogen for 5 min in the temperature range of 500 - 900∞C. Vacuum annealing lead to an increase of the background PL unrelated to Tb. In both regimes of annealing, the best results for thin SiO 2:Tb films were obtained in the temperature range of 650 - 700∞C. After treatment at this temperature the Tb PL increased by 2.5 - 3 times.

ON A MODEL OF THE TYPICAL CELL FROM A SOLAR PANEL Minerva Cristea, Viorel Chiritoiu, Marius Costache, Ioan Zaharie, Ioan Luminosu Department of Physical Foundation of Engineering, University “Politehnica” of Timisoara, Bv. Vasile Pârvan No.2, 300223, Timisoara, Romania ABSTRACT This paper presents theoretical and experimental researches concerning of application a mathematical model for a photovoltaic panel. The panel has in his structure 36 Si cells in a serial circuit of ST40 type. The experimental characteristic I-U for the panel is given by the producer for different five insolations at one constant temperature. In order to know the behaviour of the panel and because of variation of insolation in a whole day is necessary an interpolation process who can approximate a panel which is made by an association of cells. Our model allows establishing the characteristic I-V for an average (typical) cell from serial circuit of the panel. The experimental characteristics of individual cells present a deviation from the modeled cell, but when we place the cells in a panel we obtain a statistical equalization. The simple mathematical model proposed in this paper describes the typically cell for our panel working at a constant temperature. A simple mathematical model is drawn from the equivalent electrical circuit with a single diode assuming the shunt resistance as infinite. This model allow us to determine the optimally working point for a typically cell and for a panel made by association of cells for different insolations. The results which we have obtained yield to a numerically simulation of photovoltaic panels made by one type cells in different naturally insolation conditions. Associated to this circuit, the following expression gives the current-voltage dependence:

where: I – the cell current, IL - light-generated current (photocurrent), IL = ·E for solar irradiance up to E= 1 kWm-2 , · – constant depending of cell type, I0 – diode reverse saturation-current, V – voltage of cell, q – elementary electrical charge, k –Boltzmann’s constant, n – diode ideality factor. For V = 0, the diode contribution is neglected and the short-circuit photocurrent Isc is proportional with solar irradiance. In our considerations we have taken into account the losses due to Rs , but we neglect the effects of Rsh. In this conditions the cell characteristic is in form:

81

The short-circuit current Isc (for V = 0) is just the light-generated current IL, that is Isc = ·E and is not strongly temperature-dependent. In order to construct the model, we have to extract the four parameters, ·, Rs, n and I0, involved in eq. (2). The series resistance, dependent on the illumination intensity, has a significant effect on the performance of a PV module, especially in the upper voltage part, where the power loss due to the series resistance is most significantly, and an accurate knowledge of the series resistance is important in computer modelling of a PV cell behavior. The series resistance was determined by the method of two characteristic curves and different analytical methods. A formula for the diode ideality factor is derived in this case. In order to find the n ideality factor we have considered the electrical maximum power point for the investigated cell: When V and I have values which optimize the electrical power V=Vmpp, I=Impp, from the condition of maximum electrical power (dP/dI)=0, or (dP/dV)=0. The power is maximum when , so dV/dI = -V/I, and solving by numerical methods the obtained transcendental equation, we established the next expression for ideality factor:

This simple model offers easily a possibility for simulation and prediction of the cell behavior in the different natural conditions. It was experimentally verified and we consider that it represents a useful tool for low power terrestrial utilizations.

COMBINED SOLAR AND WIND ENERGY SYSTEMS Y. Tripanagnostopoulos 1, M. Souliotis 2, Th. Makris

3

Department of Physics, University of Patras, Patras 26500, Greece, e-mail 1 : [email protected], e-mail 2: [email protected], e-mail 3 : [email protected] ABSTRACT Energy demand of buildings in electricity and heat corresponds to about one third of the total energy consumption in many countries. Renewable energy sources can be used to cover a great part of energy needs in the built sector, contributing to the conventional energy saving and also to the protection of the environment. Solar energy systems as thermal collectors and photovoltaics are installed on the roof or the façade of buildings to cover hot water and space heating/cooling needs and to provide electricity for lighting and operation of several electric devices. PVs convert a small part of the incoming solar radiation to electricity, with the greater part being converted into heat. This effect increases their temperature, resulting to its efficiency drop. The combination of the PV module with a water heat extraction unit constitutes the hybrid photovoltaic/thermal (PV/T) system, by which electrical and thermal output is simultaneously provided. In hybrid PV/T systems the extracted heat from PV cells increases the temperature of the heat removal fluid, which can be stored in a thermal storage tank. Wind energy is a very promising renewable energy source, estimating to cover the 20% of the global electrical energy demand in 2020. The integration of the usual medium or high power wind turbines (WT) on buildings is not practical and small size wind turbines are recommended. The facades and the horizontal or inclined roofs of several buildings are appropriate surfaces for the application of photovoltaic panels and thermal collectors, for the electricity and heat demand respectively. Apart of them small wind turbines (WTs) can be mounted on building roofs, mainly at locations with satisfactory wind velocity potential and are effective to both stand-alone and grid connected applications. Regarding building integrated wind turbines (BIWT) the dimensions and the weight of them are two important factors that must be taken into consideration and mainly small size systems are suitable. Small WTs must be of low cut-in wind speed and also aesthetically compatible with the building architecture. The produced electricity from PVs and small WTs can be transmitted to the electrical grid, but as solar and wind energies vary with time, energy storage could be used to adapt the time of energy conversion with the demand profile. In PV/T system applications and considering that the electricity is of priority, the operation of the PV modules at lower temperatures is necessary in order to keep PV cell electrical efficiency at a sufficiently higher level. This demand limits the operation range of PV/T system thermal unit in lower temperatures and the extracted heat can be mainly used for low temperature thermal needs (space heating and natural ventilation of buildings, air or water preheating, etc). In this paper we present the new concept of combined solar and wind energy systems for building application. Photovoltaics (PV) and small wind turbines (WT) can be installed on buildings, in case of sufficient wind potential, 82

providing the building with electricity. The PVs (or the PV/Ts) and WT subsystems can supplement each other to cover building electrical load. In case of using PV/T collectors, the surplus of electricity - if not used or stored in batteries - can increase the temperature of the thermal storage tank of the solar thermal unit. The description of the experimental set-up of the suggested PV/T/WT system and experimental results are presented. In PV/T/WT systems the output from the solar part depends on the sunshine time and the output of the wind turbine part depends on the wind speed and is obtained any time of day or night. Thus the PV/T and WT subsystems can supplement each other and achieve an optimal use of the solar and wind potential on a building. The use of the three subsystems can cover a great part of building energy load, contributing to conventional energy saving and environment protection. Hybrid photovoltaic-wind and/or Diesel systems can offer great abilities in the production of energy based on solar and wind energy. In regions where sunshine and wind conditions are good, like the Greek islands, the combined use of photovoltaics and wind turbines has great results for most of the day-night period and also for a very large period of a year, with the thermal collectors covering thermal needs all year round. The PV/T/WT systems are considered suitable in rural and remote areas with electricity supply from stand-alone units or minigrid connection. PV/T/WT systems can also be used in typical grid connected applications. For stand-alone PV and WT systems, diesel generators are used in case that solar and wind energies are not sufficient to cover the electrical load.

DESIGN AND PERFORMANCE OF A HYBRID PV/T SOLAR WATER HEATER Y. Tripanagnostopoulos, M. Souliotis, Th. Makris, P. Georgostathis, M. Sarris Department of Physics, University of Patras, Patras 26500, Greece, Tel: +30 2610 997472, e-mail: [email protected] ABSTRACT Flat Plate Thermosyphonic Units (FPTU) and Photovoltaic devices are well known solar systems that provide heat and electricity, respectively. The hybrid Photovoltaic/Thermal (PV/T) solar systems can simultaneously provide electricity and heat, achieving a higher conversion rate of the absorbed solar radiation than standard PV modules. When properly designed PV/T systems can extract heat from PV modules, heating water or air, aiming to reduce the operating temperature of PV modules and to keep the electrical efficiency at a sufficient level. In this paper we present design considerations and experimental results of a thermosyphonic hybrid PV/T solar system that is investigated at the University of Patras. The system is analyzed with respect to their design, electrical and thermal energy output for a pc-Si PV module type under the climatic conditions of Patras. The hybrid PV/T solar water heaters can be effectively used for domestic water and space heating and other applications, contributing also to the electrical consumption of the buildings. The investigated PVT/WATER models consist of silicon PV modules and the heat extraction unit is a metallic sheet with pipes for the water circulation, in order to avoid the direct contact of water with the PV rear surface. This heat exchanger element is in thermal contact with PV module rear surface and is thermally insulated to the ambient from the rear side and the panel edges. PV/T systems without additional glazing (PVT/UNGL), provide satisfactory electrical output (depending on the operating conditions), but the thermal efficiency is reduced for higher operating temperatures due to the increased thermal losses from the PV module front surface. The addition of glazing (PVT/GL) increases the thermal efficiency for a wider range of operating temperatures, but the additional optical losses reduce the electrical output of the PV modules. Hybrid PV/T systems can provide electrical and thermal energy, thus achieving a higher energy conversion rate of the absorbed solar radiation. We tested outdoors PV/T prototypes consisted of pc-Si PV modules and heat exchanger of copper sheet with copper pipes, for two system types (PVT/UNGL and PVT/GL). We used commercial PV modules, which give about 8%-15% efficiency, depending on the operating temperature and the use or not of additional glazing. During the experiments the generated electricity was transmitted to a load, simulating real system operation. The steady state tests were performed outdoors and the results for the collector obtained thermal efficiency are given. The glazed PV/T collector presents remarkably higher thermal output than the unglazed PV/T collector, but the electrical output of it is reduced due to additional optical losses. The design of the studied thermosyhonic hybrid PV/T solar system is mainly based on the necessity of producing electricity and hot water at the same time, effectively. This solar device consists of a PV panel, a heat exchanger and a storage tank of specific water volume. The ratio of the stored water volume per aperture area is determined by the electrical and heat energy needs. The solar device was experimentally tested outdoors in order to investigate so the water temperature rises as the temperature stratification of the stored water inside the storage tank. In addition we study the impact of the temperature on the electrical efficiency of the system. The mounting of a diffuse reflector in front of the PV/T collector can contribute to system performance improvement due to the higher rate of incoming solar radiation on PV surface. 83

The experimental results include variation of the water temperature in storage tank during daily and night operation of the system. Same results were taken for a sequence of 3 days in order to investigate the maximum of the water temperature rise. Variation diagrams of the mean daily efficiency and the coefficient of thermal losses during night are also presented. In addition, we present experimental results of the electrical efficiency versus the operating temperature of the system and we give I-V curves for several weather conditions and operating temperature, as well. The experimental study of the tested thermosyphonic hybrid PV/T solar device showed that can perform effectively during all year long, achieving at least 40 ÆC of hot water and producing electricity at a satisfactory level. The approach of combined solar devices producing electricity and heat at the same unit can be useful for the design and development of low cost solar devices with efficient electrical and thermal performance.

TEMPERATURE DEPENDENCE OF NMR T1 AND T2 RELAXATIONS OF CROWN ETHER DERIVATIVES ERTEKIN BINBAY, N. and YILMAZ, A Department of Physics, University of Dicle, 21280 Diyarbakir Turkey ABSTRACT The NMR studies of crown ethers are still of scientific interest due to their extensive use in chemistry, atomic and medical industry. A new study on the dynamical behaviour of these molecules in solution would therefore be useful. In this work, the proton spin-lattice (T 1) and spin-spin (T2) relaxation times of several peaks in 18-crown 6 ether derivatives were measured versus temperature by using Avance Bruker 400 MHz NMR spectrometer. The temperature of samples was changed from between 20 oC to 45 oC by steps of 5 oC. In addition, a computer simulation was used to find optimum conformation of each ligand in solution. The simulation exhibits thorus like appearance for optimum conformation of both ligands. The observed T1 increase nearly linearly with increasing temperature, while T2 decrease monotocally for both ligands. The temperature dependence of T1 data is consistent with dipolar relaxation, while that of T2 data is consistent with spin-rotation interaction. The range of correlation times, calculated from the relevant theories, was order of ns for T1 and ps for T2. The results are consitent with literature. The data and calculations suggest that T1 relaxation is caused by dipolar interaction, but T2 is caused by spin rotation interaction

THE OBSERVATION OF THE HOD TRIPLET IN H 2O/D2O CONTAINING ALBUMIN BY 400MHz NMR, AND THE DEMONSTRATION OF THE RADIATION DAMPING CAUSED BY STRONG COUPLING BETWEEN MAGNETIC FIELD AND RF COIL Yilmaz A 1, Zengin B 1 and Tez M 1Department 2Department

2

of Physics, University of Dicle, 21280 Diyarbakir-TURKEY of Mathematics, University of Marmara, Istanbul-TURKEY

ABSTRACT H2O/D2O mixtures are being used as solvent for proteins. Since NMR spectrum of the mixture show a single line, the studies involving such materials are mainly based on water signal. However, some recent studies have revealed an HOD triplet by indirect measurements. Exploring this triplet should be very important for solving difficulties in analyzing relaxation and j-coupling data obtained in H2O/D2O medium. On the other hand, the radiation damping due to strong coupling between high proton magnetization and RF coil causes a problem for measuring relaxation times at higher NMR frequencies. Demonstrating the radiation damping may be useful for getting reliable T1 and T 2. In this work, Inversion Recovery (IR) curves of residual water in the presence and absense of 0.2g albumin were acquired for a set of delay times with an incremental increase of 20ms. The similar experiments were repeated for a mixture of 0.1H2O and 0.9D2O containing various amounts of albumin. Since there is disproportionation reaction between H2O and D2O, the time dependence of the IR curves was studied for the delay times ranging from 3ms to 750ms by using a fixed increment of 3ms. The dependence of the IR curves on the value of the increment was also studied. The experiments were carried out on a BRUKER AVANCE-NMR spectrometer operating at 400 MHz. The IR pulse sequence (180 o-delay time-90o) was used to acquire IR curves. The data of the residual water containing 0.2g albumin shows a triplet on the tail of IR curve. This triplet was confirmed further through the data obtained from the mixture. The triplet was attributed to the splitting of H signal by D. The incremental step and time dependences of the triplet exhibit damped ossilations, which are attributed to the 84

radiation damping. Such a damping is completely over around 0.5ms. The present data suggest that the direct detection of the triplet may provide some valuable information for the nature of water-albumin interactions. The data also suggest that selecting a sutiable range of delay times provides a reliable T1 values by IR for certain H2O/D20 mixtures.

COMPUTER SIMULATIONS OF HUMAN INTERFERON GAMMA MUTATED FORMS E. Lilkova 1, L. Litov 1, P. Petkov 1, P. Petkov 2 , S. Markov 3 and N. Ilieva

4

1Department

of Atomic Physics, Faculty of Physics, University of Sofia, Bulgaria 2 Faculty of Chemistry, University of Sofia, Bulgaria 3Institute for Parallel Processing, Bulgarian Academy of Sciences, Bulgaria 4 Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Science, Sofia, Bulgaria ABSTRACT General introduction in the computer aided drug design is given. Basic elements of building computer models of biological molecules and description of their interactions are considered. The methods are illustrated on the example of investigation of human interferon-gamma (INF-g) and both its known ligands (its extracellular receptor and heparin derived oligosaccharides) binding. One of the principal tools in the theoretical study of biological molecules is the method of molecular dynamics simulations. Here, we present a study of 100 mutants of human interferon gamma with mutated residues 86-88 using MD simulations. The structural changes are investigated by comparing the lengths of the a-helices, in which these residues are included, in the native human interferon gamma molecule and the mutated forms. The results are also compared with the predictions of the hydrophobic-polar model. Some of the more intriguing cases are examined in more details.

HELIO-GEOMAGNETIC ACTIVITY AND THE TIME DISTRIBUTION OF MYOCARDIAL INFRACTIONS DURING THE SOLAR CYCLE 23 (1997-2007). A PRELIMINARY STUDY BASED ON A GREEK HOSPITAL DATA X. Moussas

(1),

P. Preka-Papadema

(1),

Th. Apostolou (2) , Ch. Katsavrias and Th. Papadima (3)

(1),

A. Theodoropoulou

(1)

Section of Astrophysics, Astronomy and Mechanism, Dept of Physics, University of Athens, Greece (2) General Hospital of the town of Nikea (Piraeus) ‘St. Panteleimon’, Greece (3) General Hospital of Athens ‘Evagelismos’, Greece ABSTRACT (1)

We present the time distribution of 7798 Myocardial Infractions (MI) recorded at the General Hospital of the town of Nikea (Piraeus) ‘St. Panteleimon’, during time interval 1997-2007. This data set consisted of 5160 NON-STEACS (non-ST) and 2638 STEACS (ST) infractions are examined along with the monthly numbers of solar flares and Coronal Mass Ejections (CMEs), solar wind parameters and the geomagnetic activity (Dst and Kp geomagnetic indices). The main monthly value of ST and non-ST events is 20 and 40 respectively. The maximum monthly value of non-ST events (72-73) is recorded in October 2002 and January 2003, as well as the one of ST events (32), until solar maximum, recorded in November 2002. This time interval characterized by magnetic storms from August 2002 peaked in October 2002 and ended in February 2003. It is noticeable that August 2002 corresponds to the solar maximum of CMEs and strong solar flares monthly values. The maximum monthly value of ST events (40) is recorded in November 2005 almost simultaneously with a sudden absence of solar flares (October 2005). Increased values have been recorded during a period of extreme solar events of October-November 2003 and January-March 2003. It seems from this extensive statistical study that there is an association between the monthly values of MI and of CMEs; the non-ST events show a better association with CMEs. Moreover, the MI yearly distribution is in accordance with the time distribution of magnetic storms (number and duration). The non-ST distribution is also affected by intense magnetic storms.

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ESTIMATION OF ANTOCYANIN CONTENT OF BERRIES BY NIR METHOD G. Zsivanovits, D. Ludneva, Angel Iliev Agricultural Academy of Bulgaria, Canning Research Institute, Plovdiv, 154 Blvd. Vasil Aprilov 4000 Plovdiv, Bulgaria, [email protected] ABSTRACT Anthocyanin contents of fruits were estimated by VIS spectrophotometer and compare with spectra measured by NIR spectrophotometer (600-1100 nm step 10 nm). The aim was to found relationship between NIR method and traditional spectrophotometric method. The testing protocol is easier, faster and non-destructive. NIR spectra were prepared in pairs, reflectance and transmittance. A modular spectrocomputer, realized on the basis of a monochromator and peripherals Bentham Instruments Ltd (GB) and a photometric camera created at Canning Research Institute, was used. An important feature of this camera is the possibility offered for a simultaneous measurement of both transmittance and reflectance with geometry patterns T0/180 and R0/45. The collected spectra were analyzed by CAMO Unscrambler 9.1 software, with PCA, PLS, PCR methods. Based on the analyzed spectra quality and quantity sensitive calibrations were prepared. The results showed that the NIR method allows measuring the total anthocyanin content in fresh berry fruits or processed products without destroying them.

CALCULATIONS OF THE HUMAN VITAMIN D EXPOSURE FROM UV SPECTRAL MEASUREMENTS AT THREE EUROPEAN STATIONS Melina Maria Zempila,

a

Andreas Kazantzidis, a Alkiviadis F. Bais, a Stelios Kazadzis, Outer, c Tapani Koskela b and Harry Slaper c

a, b

Peter N. den

Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, Thessaloniki ,Greece b Finnish Meteorological Institute (FMI), Helsinki, Finland. c Laboratory of Radiation Research, National Institute of Public Health and Environment (RIVM), Bilthoven, The Netherlands a

ABSTRACT The international countermeasures taken in the context of the Montreal protocol and its amendments are expected to lead to a slow total ozone recovery in the coming decades, and the onset of the ozone recovery has been detected. However, many uncertainties still exist regarding the future UV radiation levels, because ongoing climate change interacts with ozone changes and in addition climate change can also have important direct implications for the future UV climate, through changes in the cloudiness and atmospheric dynamics. Up to 2006 at least, the surface ultraviolet (UV) irradiance continues to increase at rates of a few percent per decade at most mid-latitude stations in the Northern Hemisphere. Excess UV irradiance levels now, are, for a stationary population, expected to lead to a peak of global incidences of skin cancers around the year 2050. Excess cases of skin cancer are then of the order of 200 per million per year, if compliance with Montreal protocol is fulfilled. It is also estimated, that up to 60,000 deaths per year worldwide were caused by the excessive exposure to UV radiation, which is related to skin cancer, DNA damages etc. In recent years however, the beneficial health effects due to UV exposure are being evaluated and discussed extensively. Skin pigmentation and age evidently affect the cutaneous production of vitamin D3. The influence of season and latitude on the cutaneous synthesis of vitamin D3 was initially described by Webb et al. They revealed that a minimum biologically effective UV dose rate is needed for the detection of provitamin D photo conversion to previtamin D. Based on their method results, a detection threshold value of 3.46 mW m-2 was proposed by Engelsen et al. According to their findings and in dependence with atmospheric conditions, the vitamin D production can be absent for latitudes higher than 50 degrees (“vitamin D winter”). In our study, we have calculated the vitamin D effective dose (VDED) from quality-checked spectral UV irradiance measurements at three European stations, Jokioinen (Finland), Bilthoven (The Netherlands) and Thessaloniki (Greece), representing different geographical and environmental conditions. All spectra are weighted with the previtamin D and the erythemal action spectra, in order to establish an empirical relationship between the two biological quantities. The days of year are examined where the VDED for local noon, 9 and 16 local times is higher than the detection threshold value of 3.46 mW/m2. We also indicate the minimum recommended exposure time to achieve a standard VDED for different skin types. In many published studies on this subject the action spectrum proposed by McLaughlin et al. was used, therefore we examine the differences in VDED levels due to the two different action spectra (McLaughlin and CIE), as derived from measurements. According to our results the maximum average daily VDED is measured during the second half of June thus 86

revealing the dominant effect of solar zenith angle and cloudiness. The average VDED rates at local noon did not exceed the detection threshold value for the cutaneous production of vitamin D 3 at Bilthoven from mid November to the end of January, while this time period is expanded by almost one month in Jokioinen. The proposed standard vitamin D dose (SDD) cannot be attained, for an exposure time of 60 minutes around local noon and for skin type I-III, under physiological atmospheric conditions even in Thessaloniki for almost 3 months. The daily VDED values, using the CIE action spectrum, are higher at all sites, compared with those derived by the action spectrum proposed by McLaughlin et al., but the differences lying within the uncertainties of the spectral measurements. Additionally, a polynomial fit is proposed for every site between the VDED and the erythemal dose rates (EDR). These quadratic equations can be used to any other site with similar atmospheric and geographical conditions, where UV and Ozone data are not available.

STUDY ON THE LIPID IMPREGNATED ULTRA-FILTERS BEHAVIOR: AN ELECTROCHEMICAL APPROACH TO THE DEVELOPMENT OF BIOMIMETIC MEMBRANE SYSTEMS Efstathios K. Matsaridis, Varban M. Savov Department of Atomic Physics, Sofia University ‘‘Kl. Ohridsky’’, 5 J.D. Bourchier, Sofia 1164, Bulgaria ABSTRACT Ultra-filters impregnated with lipids or/and their analogues turn out to be highly perspective in the development of new types biomimetic membranes (BMM). Some of their features such as stability, relatively large size, high impedance, ion selectivity etc. can be pointed out as beneficial for the construction of artificial analogues of natural membranes. On the one hand, these properties depend on the type of ultra-filter used - pore density, mean pore diameter and distribution, fiber material. On the other hand, impregnating substance and preparative techniques (impregnation procedure) are important as well. The experimental data about electrochemical characteristics of such systems obtained by impedance spectroscopy (IS) allow working-out of BMM physical model.

INVESTIGATING THE KINETICS OF CO 2 TRANSPORT THROUGH LIPIDIMPREGNATED POLYMER FILTERS Efstathios K. Matsaridis, Nellie Zheleva Department of Atomic Physics, Sofia University ‘‘Kl. Ohridsky’’, 5 J.D. Bourchier, Sofia 1164, Bulgaria ABSTRACT Due to their useful properties, polymer filters impregnated with lipids or their analogues are widely employed in numerous areas of Chemistry, Biology and Medicine. In this work we present a designated model system that allows the examination of some aspects of CO2 transport via natural liquid barriers in the organisms, e.g. alveolar surfactant, blood plasma etc. This system comprises of a specially designed electrochemical cell divided of two compartments, by properly impregnated porous filter. The features of the set-up were explored and analyzed from the viewpoint of its ability to render the transport of CO2 through different liquid phases, mimicking the conditions in vivo

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TIGHT BINDING PARAMETERS FOR CHARGE TRANSPORT IN DNA L. G. D. Hawke 1, G. Kalosakas 1, C. Simserides 1 2

2

Materials Science Department, University of Patras, GR-26504 Rio, Greece Institute of Materials Science, NCSR Demokritos, GR-15310 Athens, Greece

ABSTRACT

[1] L.G.D. Hawke, G. Kalosakas, C. Simserides, Mol. Phys. (2009) in press. (arXiv:0808.3984v2) [2] L.G.D. Hawke, C. Simserides, G. Kalosakas, Mater. Sci. Eng. B (2009) in press. doi:10.1016/j.mseb.2009.02.012 [3] L.G.D. Hawke, G. Kalosakas, C. Simserides, ‘Tight binding parameters for charge transfer along DNA’, preprint (2009). [4] R.G. Endres, D.L. Cox, R.R.P. Singh, Rev. Mod. Phys. 76, 195 (2004). [5] J.C. Slater, G.F. Koster, Phys. Rev. 94, 1498 (1954). [6] M. Menon, R.E. Allen, Phys. Rev. B 38, 6196 (1988). [7] N. Lathiotakis, A.N. Andriotis, Solid State Comm. 87, 871 (1993).

DEVELOPMENT OF A NOVEL PET IMAGING SYSTEM, BASED ON RESISTIVE PLATE CHAMBERS (RPC) N. Ilieva Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences V. Kozhuharov, I. Lesigyarska, L. Litov, B. Pavlov, P. Petkov, I. Tabanlijski Faculty of Physics, University of Sofia “St. Kl. Ohridski” ABSTRACT The RPC detectors are widely used in HEP experiments for detection of charged particles. They are known for their very good spatial and excellent time resolution. Transforming them into detectors for gamma rays, opens the way towards their application in the medical imaging, as a basic element of a hybrid imaging system, which combines Positron Emission Tomography (PET) with Magnetic Resonance Imaging (MRI). A novel PET system, based on gas-operated Resistive Plate Chambers (RPC), may provide significantly higher position resolution for the gamma quanta impact point 88

in the detector (100-150 mm) and time-of-flight measurement with accuracy better than 50 ps FWHM, compared to the scintillating crystals, traditionally used in PET devices. In turn, this will allow reconstruction of the image with precision better than 1 mm. Further advantage of the RPC is their ability to work in the presence of strong magnetic fields, making thus possible the combination of PET and MRI in a single device. We present the first results of the material investigations for photon-efficiency optimization of the detector.

MONITORING OF DOSE RATE FOR DIAGNOSTIC CLINICS STAFF USING TLD-100 CARDS (2003 - 2007) Luan QAFMOLLA, *Enver HOXHAJ Center of Applied Nuclear Physics (CANP), *University of Shkodra, Department of Physics ALBANIA ABSTRACT In our paper is described the monitoring of occupational staff that works in ionizing radiation field of dental clinics and diagnostic centers in Albania for 2003-2007 period. In our paper is analyzed and discussed the mean annual dose rate recorded for employees of the ionizing radiation fields. Dosimetric Service of the Department of Human & Environment Protection at the Center of Applied Nuclear Physics carried out the monitoring for about 350 employees for 2003-2007 periods. The monitoring is based in use of the TLD-100 dosimetric cards and the control is performed bimonthly for occupational staffs of the important regions like: Tirana, Durresi, Shkodra, Fieri, Vlora, Korça etj. Key - words: TLD dosimeter, staff monitoring, radiation dose

ANALYSIS OF CHANGES OF CARDIOLOGICAL PARAMETERS IN MIDDLE LATITUDE REGION IN RELATION TO GEOMAGNETIC DISTURBANCES AND COSMIC RAY VARIATIONS M. Papailiou1, S. Dimitrova 2, E. S. Babayev 3, H. Mavromichalaki

1

1Nuclear

and Particle Physics Section, Physics Department, University of Athens, 15771, Athens, Greece ([email protected]; [email protected]) 2Solar-Terrestrial Influences Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, Block 3, 1113 Sofia, Bulgaria ( [email protected]) 3 Shamakhy Astrophysical Observatory (ShAO) named after N. Tusi and Institute of Physics, Azerbaijan National Academy of Sciences; 10, Istiglaliyyat Street, Presidium of Academy, Baku, AZ-1001, The Republic of Azerbaijan ( [email protected]) ABSTRACT A number of recent studies show that the human physiological/cardio–health state can also be affected by such space weather changes like geomagnetic activity and cosmic ray intensity variations. Three collaborating scientific groups from Athens (Greece), Baku (Azerbaijan) and Sofia (Bulgaria) have worked on the subject of how geomagnetic field disturbances (including geomagnetic storms of various strengths) and cosmic ray intensity variations (well expressed also by Forbush decreases) may have an influence on human homeostasis, particularly, the cardio-health. Electrocardiograms (ECGs) of seven functionally healthy persons were digitally registered at the Laboratory of Heliobiology, the Medical Centre INAM, Baku on working days and Saturdays. Heart rate values, estimated from ECGs, were analysed in relation to daily values of cosmic ray intensity, as measured by the Neutron Monitor of the University of Athens (http://cosray.phys.uoa.gr) and daily variations of Dst and Ap geomagnetic indices. The preliminary study revealed quite interesting results; the heart rate increased on the days before, during and after geomagnetic storms with high intensities and on the days preceding, during and following cosmic ray intensity decreases. Researches were continued by the aforementioned groups using additional parameters estimated from the same ECGs. The data concern the same group of people and refer to the time period from 15th July 2006 until 31 st March 2008. In this study data of RR_minimum, RR_maximum and RR_average were analysed for different levels of geomagnetic field disturbances (estimated through variations of Dst and Ap indices) and cosmic ray activity (i.e., cosmic ray intensity variations, %); the RR interval is the time measurement between the R wave of one heartbeat and the R wave of the preceding heartbeat. RR intervals are normally regular, but may be irregular with sinus node disease and supraventricular arrhythmias. Results of these collaborative studies show that geomagnetic activity changes and cosmic ray intensity variations could be considered as one of regulating external factors in human homeostasis. 89

THE DETERMINATION OF THE QUANTUM YIELD IN THE FLUORESENCE SPECTRA OF PORPHYRINS Odeta Çati 1, Kejda Kristo 1, Marenglen Spiro 2, Emil Xhuvani 1, Fatbardha Babani 1 Tirana

1,

Dentila Tafa

3

University, Faculty of Natural Sciences, e-mail: [email protected] University, Tirana, 3 High School N. Frasheri, Durrres

2 Kristal

The porphyrins, natural macromolecules, and especially the glycosylated ones, are recently used in the photodynamic therapy of different kinds of tummor cells. The porphyrins are injected through intravenous way in the humman body. Under appropriate radiation of tummor zone with light in UV region, oxidation processes of the porphyrins ocourr through different mechanizms. As a result, inside the tummor, is producing oxygen in singlet state which is lethal for the tumor cells. The spectroscopic study of the porphyrins, both the absorbtion and the fluoresence spectroscopy, reveals some properties of the porphyrins which are ralated with their eventual aplication in the photodynamic therapy. So, from the value of the quantum yield, which is an important quantity that derives from the measurement of fluoresence of porphyrins, one can judge, through which mechanizm, the oxidation process does occours. This suggest how the porphyrin should be used in the therapy, as monomers or as agregates. The porphyrins are sinthetised in the Laboratory of Chemistry of Natural Compaunds, in the University of Limoges. The spectra has been taken by means of a photospectrometer, in the university of Tirana. The fluoresence spectra of the “protected”and “unprotected” porphyrins are studied. The determination of the quantum yield has been done through the comparison of porphyrins spectra, with them of Rodamine B, which has a large fluoresence, in the same region of spectrum where does ocourr the fluoresence of porphyrins. In order to do that, the calculations of the surface under the fluoresence spectra and under the Rhodamine one, is necessary. Also, the extintion of the fluoresence of some “protected” porphyrins, in polar solution, has been detected. These extintion of fluoresence has to do with the formation of agregates, of dimmers, which can be confirmed even from the absorbtion spectra.

QUANTUM CHEMICAL STUDIES ON TAUTOMERISATION AND PROTONATION BEHAVIOURS OF SOME NOVEL DRUG PRECURSOR 6ACYLBENZOTHIAZOLON DERIVATIVES Yadigar Gülseven 1 , Isa Sidir 1 , Erol Ta {al 1 , Cemil Ö ñretir 1 Eski {ehir 2Eski {ehir

1

Osmangazi University,Faculty of Arts & Sciences, Department of Physics, Eski Osmangazi University, Faculty of Arts & Sciences, Department of Chemistry, Eski

{ehir,Turkey {ehir, Turkey

ABSTRACT 2-Benzothiazolinone derivatives were reported as anti-inflammatory and analgesic activities agents in the literature [1,2]. In this study, the acidity constants, proton affinity, tautomeric equilibrium constants and relative stability of some new 6-achylbenzothiazolon derivatives were calculated by the semi-empirical molecular orbital (AM1, PM3 and PM5) theory. All the calculations were done by using CAChe work system proversion 6.1 software. 1-Oxo and 2-oxo protonation values of benzothiazol-2-one derivatives were obtained and it was observed that they are close to protonation values of 2-oxo benzimidazole of -2.24[3]. The results of AM1 calculation indicate that molecule 5 has more weakly acidity constant among the studied molecules.The calculated relative stability (RS) and tautomeric equilibrium values were indicated the stability of keto form over enol form.

90

Molecule No 5 6 7 8

R

R1

R2

CH3 CH2CH3 CH(CH3)2 CH2CH2CH2CH3

H H H H

COC6H5-4-CH3 COC6H5-4-CH3 COC6H5-4-CH3 COC6H5-4-CH3

Scheme. Possible tautomeric equilibria of investigation 6-acylbenzothiazolon derivatives [1]. Ferreira S.H., Lorenzetti B.B., Devissaguet M., Lesieur D., Tsouderos Y., Br. J. Pharmacol., 114, 303, 1995. [2]. Ünlü S., Önkol T., Dündar Y., Ökçelik B., Küpeli E., Ye_ilada E., Noyanalpan N., _ahin M. F., Arch. Pharm.Pharm. Med. Chem. 336, 353, 2003. [3]. Catalan J., Abboud J.L.M., Elguero S. Adv. Heterocyc. Chem. , 41, 248,1986. This work has been supported financially by Scientific and Technical Research Council of Turkey via Project number of 108T192.

DYNAMIC METHODS FOR INVESTIGATING THE CONFORMATIONAL CHANGES OF BIOLOGICAL MACROMOLECULES E. Vidolova-Angelova, Z. Peshev

c,

Z. Shaquiri b, D. Angelov a

Institute of Solid State Physics – Bulgademy of Sciences Fast conformational changes of biological macromolecules such as RNA folding and DNA – protein interactions play a crucial role in their biological functions. Conformational changes are supposed to take place in the tens of Ìs – seconds time range. The development of appropriate dynamic methods possessing both high space (1 nucleotide) and time resolution is of important interest. Two different approaches have been developed by us. The first one is based, from one side, on the absorption spectrum shift of the rare t-RNA base s4U enabling its selective excitation. From the other side, the approach is based on the measuring the triplet excited state lifetime of s4U that is sensitive to the 3D- conformation. Measuring the triplet excited state decay curves vs. the temperature and the ionic strength of the solution by laser transient absorption spectroscopy, we followed the equilibrium conformational changes induced by these agents. Only a single laser pulse was sufficient to accurately measure the whole decay curve which may be used in dynamical experiments. The second approach is based on the UV – laser induced photofootprinting of DNA – protein complexes. In this approach we exploited the DNA conformational sensitivity of the generation of nucleotide photomodification induced by a single high-intensity laser pulse. In contrast to the low-intensity UV photochemistry, UV laser-induced DNA photodamage proceeds via biphotonic absorption and generation of base radical cation by ionization. The very high DNA local conformational sensitivity of the photophysical process of generation of the guanine radical cation, involving energy migration and hole transport phenomena, as well as of its chemical reactivity allows a single UV laser pulse to be used as an agent for studying the interaction of proteins with DNA, i.e. to perform a “photofootprint”. Briefly, the distribution of the DNA damage spectrum changes drastically upon protein binding. By coupling and synchronizing the laser with a quenchflow device, millisecond DNA-protein interaction dynamic experiments at a nucleotide resolution have been realised. We found that the transcription factor NF-_B binds first to the center of the target DNA with fast rate limited by the diffusion, followed by a slow (1s) rearrangements towards the periphery. Mathematical modeling is under way.

SPECIAL RADIATION PROTECTION PRECAUTIONS IN THERAPEUTIC NUCLEAR MEDICINE A.P.Stefanoyiannis 1University

1,

J.Gerogiannis

2

General Hospital of Athens “Attikon”, Athens, Greece 2 Nicosia General Hospital, Nicosia, Cyprus

ABSTRACT Therapeutic Nuclear Medicine concerns the administration of appropriate amounts of radioactivity of certain isotopes, in order to achieve internal localised irradiation of neoplasmatic cells. Due to the increased level and the specific isotope characteristics of administered radioactivity, special Radiation Protection precautions must be taken, so as to minimise the radiation burden of people involved directly or indirectly in the procedure, without compromising the therapeutic effect. This study addresses such issues, based on national as well as international legislation and guidelines. 91

Application of the principle of optimisation is of outmost importance. The objective of optimisation is the absorption of the prescribed dose to the tissue or organ under treatment in order to reach a desirable biological effect, this fact necessitating individual dose planning. The decision about the release of Nuclear Medicine patients after therapy is determined on an individual basis, taking into account patients’ pattern of contact with other people, their age and that of persons in the home environment, in addition to other factors. Estimation of the absorbed dose given to the treated organ is based on uptake measurements and other biokinetic data, as well as on the mass of the treated tissue or organ. Concerning pregnant women, the rule of thumb is that they should not be treated, unless the radionuclide therapy is required to save their lives. In that case, the potential absorbed dose and risk to the fetus should be estimated and conveyed to the patient. Additionally, any therapeutic radiopharmaceutical administered orally, intravenously or arterially is potentially hazardous to the child, and breast feeding must cease. After radionuclide therapy, a female should be advised to avoid pregnancy for the period of time depending on the specific radionuclide. This is to ensure that the dose to a conceptus/foetus would probably not exceed 1mGy (the member of the public dose limit). The radiation risk for relatives and caregivers is small and unlikely to exceed 5 mSv during the period of the patient’s treatment. Solid waste from the patient’s stay in hospital is a different matter, and is normally incinerated at high temperature along with other biological waste (which does not pose a contamination problem), or held for a period until radioactive decay brings the activity to an acceptable level. The relatively short half lives of therapeutic radionuclides make this a manageable problem.

A PRELIMINARY STUDY ON THE EFFECTS OF ELF MAGNETIC FIELD ON ION CHANNEL CURRENTS Entele Gavoçi 1 , Maria Procopio 2, Dhurata Kuqi

3,

Ferdinando Bersani

2

1 Department

of Physics, University of Shkodra, Albania of Physics, University of Bologna. Italy 3Department of Physics, Polytechnic University of Tirana, Albania 2Department

ABSTRACT There are now many published reports of the interaction of extremely low frequency (ELF) electromagnetic fields (EM) with a variety of biological systems, but the physical mechanisms for the biochemical action of ELF are still unclear. A class of interesting, though controversial hypotheses are those often referred to as “ion resonance”(IR), starting from the “ion cyclotron hypothesis” (ICR), originally proposed by Liboff in 1985, further developed in a different form by Lednev [Lednev,1991] and Blanchard [Blanchard and Blackman, 1994]. Such hypotheses assume the biological effect be the consequence of the influence of an appropriate combination of static and oscillating magnetic fields, on the kinetic of ion critical for the cell physiology, like K+ or Ca++ etc. The aim of the present work is to verify such hypotheses using the whole-cell Patch Clamp technique, a sophisticated tool capable to investigate the electrophysiological activity at single cell level, studying the “whole cell” K+ currents, subjecting the cells to a combination of static and alternate magnetic fields according to the prediction of the so-called IR hypotheses. In order to perform these kind of experiments, we have designed and fabricated a magnetic field exposure system consisting of three large orthogonal pairs of square coils surrounding the patch clamp set up, connected to the signal generation unit, able to generate different combination of static and/or alternate magnetic field, reaching a good compromise between magnetic field homogeneity and accessibility to the biological sample under the microscope. Such system, that allows a control of the magnetic field components along the three perpendicular space directions was characterized in term of field distribution and uniformity through theoretical calculations and direct field measurements. According to our results, no statistically significant changes in the potassium ion currents through cell membrane were revealed when the cells were exposed to AC/DC magnetic field combination according to the afore mentioned IR hypothesis. REFERENCES Blanchard JP., Blackman CF., 1994. “Clarification and application of an ion parametric resonance model for magnetic field interactions with biological systems”. Bioelectromagnetics 15:217–238. Lednev VV., 1991. ”Possible mechanism for the influence of weak magnetic fields on biological systems”. Bioelectromagnetics 12:71–75.

92

PREGNANCY AND RADIATION PROTECTION J.Gerogiannis 1, A.P.Stefanoyiannis

2

1Nicosia

2University

General Hospital, Nicosia, Cyprus General Hospital of Athens “Attikon”, Athens, Greece

ABSTRACT Nowadays, there are several modalities for diagnosis and therapy in medicine using x-rays. In Diagnostic Radiology (radiography, mammography, digital radiography, CT, fluoroscopy), in interventional radiology (diagnostic fluoroscopy, therapeutic procedures), in Radiotherapy (brachytherapy, external beam therapy, endovascular brachytherapy), in interventional cardiology, in Nuclear Medicine and in other specialities and image modalities (dental radiology, dual energy x-ray absorptiometry, PET/CT, urology, orthopaedic and anaesthesiology) a case of great importance is the radiation protection of a pregnant woman being patient as well as being staff. Generally, termination of pregnancy at foetal doses of less than 100mGy is not justified, based on radiation risk. At foetal doses between 100 and 500mGy, the decision should be based on the individual circumstances. In Diagnostic Radiology, when a patient undergoes an abdomen CT before the pregnancy becomes known, the radiation dose to the fetus/conceptus should be estimated; however it is extremely rare for the dose to be high enough to warrant advising the patient to consider terminating the pregnancy. Radiographs of the chest or extremities can be safely done at any time during pregnancy, if the equipment is in proper working order. Commonly, the risk of not making the diagnosis is greater than the radiation risk involved. Radiation exposure in uterus from diagnostic radiological examinations is unlikely to result in any deleterious effect on the child, but the possibility of a radiation-induced effect can not be entirely ruled out. The effects of exposure to radiation on the conceptus depend on the time of exposure with respect to the date of conception and the amount of absorbed dose. Cardiac catheterization can be performed on a pregnant patient (if it is clinically justified) and the estimated foetal doses, for well performed procedures, are typically quite small, and well bellow the level of concern for radiation effects. Finally, a pregnant worker can continue working in an x-ray department, as long as there is reasonable assurance that the foetal dose can be kept below 1mGy during the pregnancy. Nuclear Medicine procedures can be permitted in pregnancy, in particular diagnostic ones involving short lived radionuclides, provided there are strong clinical justifications and effort has been made to explore alternatives involving non-ionizing radiation. Irradiation of the foetus results from placental transfer and distribution of radiopharmaceuticals in the foetal tissues, as well as from external irradiation from radioactivity in the mother’s organs and tissues. The physical, chemical, and biological properties of the radiopharmaceuticals are the critical factors in possible placental transfer. As a rule, a pregnant woman should not be treated with a radioactive substance unless the radionuclide therapy is required to save her life. In that extremely rare event, the potential absorbed dose and risk to the foetus should be estimated and conveyed to the patient and the referring physician. Considerations may include terminating the pregnancy. In radiotherapy, special care needs to be taken for patients during pregnancy. The patient, family members, treating oncologist and other team members should carefully discuss the decisions made. A pregnant woman can receive radiotherapy, but important factors must be considered such as the stage and aggressiveness of the tumour, the location of the tumour, the stage of pregnancy, various therapies and their length-efficacy-complications etc. If a pregnant patient has cancer and needs radiotherapy, the foetal dose can be reduced by following documented expert recommendations. But, if a pregnant patient in the first trimester has been diagnosed with cervical carcinoma and has to start radiotherapy treatment, then unfortunately it is likely that pregnancy will be terminated.

DLC COATING TECHNOLOGY FOR IMPLANTABLE MEDICAL DEVICES V. K. Gueorguiev a, G. B. Hadjichristov

a,

Tz. E. Ivanov a, V. G. Ivanov b, P. Stefanov

c

Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., BG-1784 Sofia, Bulgaria Faculty of Physics, Sofia University, 5 James Bourchier Blvd., BG-1164 Sofia, Bulgaria c Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, “Acad. Georgi Bonchev” str., Bld.11, BG-1113 Sofia, Bulgaria a

b

ABSTRACT Thin layers of diamond-like carbon (DLC) have found advanced biomedical applications, e.g. for coating of implantable medical devices, such as the stainless steel stents introduced in the arteries to allow the normal flow of blood and oxygen to the heart. The coating from DLC is a safe barrier against elution of heavy metal ions from stainless steel to surrounding tissues and blood. The high hardness, wear resistance and chemical inertness, flexibility and other physical 93

properties of the DLC layers are of great importance for the operation of the stent micro-devices. A specific and major requirement for their application in medicine is the uniform high-quality coating of the inner, lateral and outer surface of the stent metal struts. Here we report on an experimental study of thin DLC layers produced by pulsed magnetron deposition on both glass and stainless steel substrates. Original experimental set-up for effective uniform coating of stents was designed. Varying deposition conditions, such as partial pressure, substrate temperature, substrate bias, deposition time and power supply, series of homogeneous DLC layers are prepared. Experimental data for DLC structure modification are collected by microRaman, Auger depth, X-ray photoelectron spectroscopy (XPS) and electrical conductivity/capacitance measurements. To optimize the technology for deposition of DLC layers, the data obtained are linked to the structure formed in the DLC films. Particularly, the sp2:sp3 composition is indicative of the physical properties of the produced DLC layers, being of special interest for their biomedical applications.

EFFECT OF AMMONIA PLASMA TREATMENT ON THE BIOLOGICAL PERFORMANCE OF PLASMA DEPOSITED POLYHEXADIMETHYLSILOXANE N. Krasteva 1, K. Hristova 1 , E. Radeva 2 , E. Pecheva 2, R. Dimitrova 3, L. Pramatarova 1 Institute

2

2 Institute of Solid State of Biophysics, BAS, Acad. G. Bonchev Str., bl.21, 1113, Sofia, Bulgaria; Physics, BAS, 3Institute of Organic Chemistry with Centre of Phytochemistry BAS

ABSTRACT Polyhexadimethylsiloxane (PHMDS) is a polymer frequently considered for biomedical applications due to its ease fabrication, low cost and biocompatibility. The major drawback of using PHMDS in osteosubstitutive engineering however is its high hydrophobicity causing extremely low cellular interaction. We investigated three different modifications of PHMDS in respect to their initial interaction with osteoblasts. PHMDS substrates were prepared by plasma deposition of hexamethyldisiloxane (HMDS) on glass coverslips in vacuum chamber under different conditions. The IR spectra evidenced that chemical composition of the obtained polymer layers strongly depend on deposition conditions: one of the layers consists more Si, while the other consists more organic (CH3, CH2) groups inside. In order to improve the cellular interaction PHMDS substrata was further hydrophylized by vacuum treatment in NH3 atmosphere. Water contact angles (WCA) showed that both unmodified PHMDS samples possess similar surface wettability independently on the way of deposition, while ammonia modification result in an increased hydrophilicity of about 150 WCA. Cellular interaction was characterized by human osteoblast-like MG63 cell model, where overall cell morphology, the viability, proliferation and the alkaline phosphatase activity were measured after 1, 3, 7 and 10 days of cultivation. The results indicated that the osteoblast attached poorly on unmodified PHMDS while hydrophilization enhanced both the amount of attached cells and their main spreading area. Coating with FN, a key protein involved in the initial cellmaterials interaction, improved significantly osteoblast adhesion but diminished the differences between samples. Nevertheless, on plasma treated PDMS surface the cells spread a bit better. In long-term culture all materials represented comparable behavior in terms of the overall morphology and viability. NH3-treated surfaces however demonstrated significantly higher rate of cell proliferation and elevated ALP activity, compared to cells cultivated on both hydrophobic PHMDS materials. Thus, we concluded that ammonia-modified PHMDS seems to be an appropriate material for bone tissue engineering. Acknowledgements: This work was supported by two National projects: with the Bulgarian Ministry of Education and Science (TK-X-1708/2007) and the Agency of Innovation of Bulgaria (NIF 02-54/2007). NATO grant CBP.EAP.RIG. 982693 is also acknowledged.

94

THE EFFECT OF HELIO-GEOMAGNETIC ACTIVITY ON THE PROCEEDINGS IN THE EMERGENCY DEPARTMENT OF TWO GREEK HOSPITALS P. Preka-Papadema (1) , X. Moussas (1) , M. Noula (2), H. Katranitsa (2) , A. Theodoropoulou (1), Ch. Katsavrias (1), Ch. Vasiliou (2), E. Kontogeorgou (2), S-M. Tsaliki (2), K. Kailas (2), and Th. Papadima

(3)

(1)

Section of Astrophysics, Astronomy and Mechanism, Dept of Physics, University of Athens, Greece (2) Nursing Dept, Technological Institute of Lamia, Greece (3) General Hospital of Athens ‘Evagelismos’, Greece ABSTRACT Study of the solar and geomagnetic activity influence on the emergency proceedings in Greece, for selected months of solar cycle 23 and especially for the year 2005 is presented. We examined the time association between the magnetic storms (Dst geomagnetic index), solar wind velocity, daily numbers of solar flares and Coronal Mass Ejections (CMEs) with the emergency proceedings. The sample of about 30000 events from two Greek hospitals (The General Hospital of the town of Lamia and The General Hospital of the town of Veria) analyzed according to diagnoses. The cardiological, ogological, neurological, orthopedical and trauma-multitrauma patients as well as pathological/surgical patients showed an increase during periods of high helio-geomagnetic activity. In order to strengthen this result, more data need to be collected and analyzed.

A SMALL FIELD OF VIEW Á-CAMERA SYSTEM WITH HIGH RESOLUTION AND SENSITIVITY D. Thanasas a, M. Mikeli a, E. Georgiou b , D. Maintas c, A. Karabarbounis a,d , N. Giokaris Papanicolas a,d , L. Ragkousis a and E. Stiliaris a,d,* b Medical

a,d ,

C.N.

a Physics Department, National & Kapodistrian University of Athens Physics Department, Medical School, National & Kapodistrian University of Athens cInstitute of Isotopic Studies, Athens d Institute of Accelerating Systems & Applications (IASA)

ABSTRACT A small field, high resolution Á-Camera system dedicated to radiopharmaceutical research and other clinical SPECT (Single Photon Emission Computed Tomography) applications has been developed in our group. The system is equipped with a 3__ in diameter HAMAMATSU R2486 Position Sensitive PhotoMultiplier Tube (PSPMT) with a 16X+16Y crossed wire anode connected in a resistive chain technique, various pixelated and homogeneous scintillation crystals and a parallel (hexagonal) hole collimator, suitable for high resolution studies. The development of correction techniques for spatial distortions and non-uniformities in planar images, which are the most common problems in small field Á-Camera systems, are presented in this work. These distortions can be eliminated by using 2D interpolation techniques based on lookup tables, which include the coordinates of reference points, stored during the calibration phase of the system for a given crystal. In order to overcome the additional irregularities in the image reconstruction produced by the resistive chain technique due to the limitation of the accumulated charge at the periphery of the field of view, a new position reconstruction algorithm is also developed. According to this methodology, the transport of the optical photons inside the scintillation crystal is modeled and the resulting charge distribution at the anodic level of the photomultiplier tube is used to calculate the incident position of the Á-ray. All these correction methods and the new position reconstruction algorithm are applied to planar and tomographic images of various, small capillary phantoms filled with water solution of 99mTc. The achieved spatial resolution of the system in planar, as well as in tomographic level, is discussed.

95

PHOTOSYNTHETIC PIGMENTS OF ZOSTERA NOLTII AND RUPPIA CIRRHOSA IN SOME ALBANIAN LAGOONS Arjana Ylli, Fatbardha Babani, Iliriana Stamo and Alfred Mullaj Department of Biotechnology, University of Tirana, Tirana, Albania ABSTRACT In the coastal lagoons of Adriatic Sea Zostera noltii and Ruppia cirrhosa are plants with seeds and flowers, that colonizes the sandy bottom of lagoons. They are capable to produce oxygen in the absence of light. Characterization of photosynthetic pigments of plants Zostera noltii and Ruppia cirrhosa, were performed during the period 2002~2008 in the Adriatic lagoons: Vilun, Kune-Vaini, Patog, Karavasta and Narta. Dynamics of chlorophylls and carotenoids during the vegetation period of these plants were characterized. As a result, the chlorophyll content of Zoostera noltii taken from the Kune- Vain lagoon is higher than at plants collected from the other lagoons The photosynthetic pigment content of the Zostera noltii plants is higher than of Ruppia cirrhosa. The differences on the distribution of these species in the analyzed lagoons are represented in this presentation.

THE GC/MS SPECTRA IN THE IDENTIFICATION OF ILLICIT AMPHET AMINE S. Gosav 1, R. Dinica 2 1Physics

Department, University “Dunarea de Jos”, Galati, Domneasca St., 47, 800081, email:[email protected] 2 Chemistry Department, University “Dunarea de Jos”, Galati, Domneasca St., 47, 800081, Romania ABSTRACT Amphetamine-type stimulants (ATS) are a group of substances, mostly synthetic in origin, that generally stimulate the central nervous system. Chemical modification of their molecular structure results in a practically unlimited number of pharmacologically active compounds, some of which are more potent stimulants than others. In recent years, gas chromatography combined with mass spectrometry (GC/MS) has made a substantial contribution in the identification and quantitation of drugs abuse in clinical and forensic toxicology. The utility of mass spectroscopy arises from the fact that the ionization process generally produces a family of particles whose mass distribution is a characteristic of the parent species. n this paper, we have analyzed some of the most popular drugs of abuse (stimulant and hallucinogenic amphetamines) by the GC/MS technique, i.e. using the ionization by electronic impact. We have found that the most characteristic fragments ions for stimulant and hallucinogenic amphetamines are those with m/e =77, m/e=91, m/e =135.

THE TOXICOLOGICAL ACTIVITY IDENTIFICATION OF AMPHETAMINE ANALOGUES BY GAS CHROMATOGRAPHY COUPLED WITH FTIR SPECTROMETRY S. Gosav 1, D. Dorohoi 2 1 Physics

Department, University “Dunarea de Jos”, Galati, Domneasca St., 47, 800081, email:[email protected] 2Faculty of Physics, ”Al.I.Cuza” University, 11 Carol I Bdv, RO 700506, Ia {i, Romania

ABSTRACT The drugs of abuse, which affect human nature and cause numerous crimes, have become a serious problem throughout the world. There are hundreds of possible amphetamine analogues, consisting of various alterations of the basic amphetamine structure. Although they retain or slightly modify the stimulant/hallucinogenic effects of parent compound, their variety makes their identification quite difficult. A number of analytical procedures for the identification of amphetamines and their analogues have recently been reported. We are presenting an update on the different methods of identification of the illicit amphetamines and analogues, which have been analyzed by gas chromatography coupled with Fourier infrared spectrometry (GC/FTIR). Our spectroscopic results emphases the fact that the amphetamines can be identified according to their toxicological activity (stimulants or hallucinogens). In addition, the GC/FTIR technique allows us to characterize the isomers of these chemical compounds, and thus to distinguish between compounds with the same molecular structure, but with different biological activity. 96

QUANTITATIVE ANALYSIS OF EXPERIMENTAL DATA ON THE EFFECTS ACCOMPANYING THE PROPAGATION OF LASER RADIATION THROUGH BIOLOGICAL-TISSUE-LIKE TURBID MEDIA Ljuan L. Gurdev, Irina A. Bliznakova, Tanja N. Dreischuh, Orlin I. Vankov, Dimitar V. Stoyanov Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko shosse, Sofia 1784, Bulgaria ABSTRACT Optical tomography is an important hopeful investigation area that is expected to provide effective non-invasive methods and instruments for early diagnosis of serious human tissue diseases. The main advantage here is the absence of risks of ionizing radiation. The numerous variants of optical tomography being developed at present require the knowledge of the optical properties of tissues and the laws governing the radiative transfer within the investigated biological objects. The main optical characteristics of importance specifying the normal and abnormal tissues and conditioning the radiative transfer are the scattering , and reduced scattering Ìrs = Ìs(1-g) coefficients, the absorption coefficient Ìa, the scattering indicatrix, and the anisotropy factor g. For optical radiation with wavelength from 400 nm to 900 nm the biological tissues are turbid media characterized by strong scattering and considerably weaker absorption. Thus, the mean free path (MFP) of a photon in tissue will be determined in practice by Ìs, i.e., MFP ~ Ìs-1. The value of the MFP in this case is usually less than 1 mm, which means that the multiple scattering effects will be essential and the radiative transfer equation should be used for quantitative analysis. A purpose of the present study is to investigate the propagation of an optical (laser) beam through a homogeneous tissue-like medium and to determine the cross-sectional radial distribution of the detected light intensity at different depths along the beam axis. Another aim of the study is to attempt achieving an analytical description, for relatively large “optical depths”, of the radial intensity distribution and the in-depth profile of the axial intensity of the beam. The final intention here is by using the analytical expressions obtained to estimate the reduced scattering and the absorption coefficients of the medium and to reach a mutual validation between the experimental and analytical results. The experimental setup makes use as light sources of laser diodes emitting collimated optical beams of about 1 mm diameter and 27 mW light power, at wavelengths of 685 nm and 850 nm. The tissue-like turbid media of different optical properties are prepared by dilution of different amounts of 20 % Intralipid emulsion by water. Then a plexiglass container – parallelepiped, is filled by any of the mixtures obtained. The axis of the incident laser beam is perpendicular to the “frontal” wall of the container. The forward propagating light power inside the container is measured by using an optical fiber of wide numerical aperture and 0.1 mm core diameter introduced into the turbid medium. The fiber is connected with an optical radiometer (Laser precision corp., USA) with a RqP-546 silicon probe in external locking regime, 14bits ADC and a computer for appropriate data processing. By a transversal radial scan of the fiber at each stepwise varied depth of interest we obtain a set of data (distribution of the received light power) for any of the prepared turbid media. The analytical description of the intensity distribution is obtained by solving the radiative transfer equation under the assumption of sharply forward directed scattering indicatrix. The indicatrix is approximated by a Gaussian angular dependence. The transversal intensity distribution in the incident laser beam is also assumed to have a radial Gaussian shape. The detected signal (the received optical power) is evaluated, taking into account the small finite aperture size and the finite angle of acceptance of the receiving fiber. As a final result, for optical depths exceeding unity, we have obtained an analytical expression describing the spatial distribution of the detected light power within the turbid medium. The analysis of the experimental data shows that they are consistent in general with the analytical description obtained. That is, the transversal signal distribution has indeed a Gaussian shape whose width varies as z3. At the same time, the axial signal profile varies as z-3. Also, the estimated values of Ìrs seem to be quite reasonable. The investigations have been supported by the Bulgarian National Science Fund under the projects DO 02-112/08 and F1511/05

97

ATOMIC ABSORPTION ASSESSMENT OF MINERAL IRON QUANTITY IN FERRITIN M. Marinova 1 L. Vladimirova

2*

1 National

Diagnostic Veterinary Research Institute “Prof. Dr. Georgi Pavlov”, 15, Pencho Slaveykov Blvd., 1606 Sofia, Bulgaria; 2*Sofia University “St. Kliment Ohridski”, Faculty of Physics, Department of Atomic Physics, 5 James Boucher Blvd. 1164 Sofia, Bulgaria; tel: +359 2 81 61 317, fax: +359 2 96 25 276 e-mail: [email protected] ABSTRACT Possibilities for quantitative determination of the number of iron atoms in the mineral core of ferritin by atomic absorption spectroscopy (AAS) are investigated in the work.Different measurements with AAS show an iron content from 1000 up to 4500 atoms per molecule ferritin [1-5]. This motivated us to investigate the amount of iron in the Horse Spleen Ferritin with atomic absorption spectroscopy under application of the Bulgarian standard BDS EN 14082/2003 Foodstuffs Determination of trace elements - Determination of lead, cadmium, zinc, copper, iron and chromium by atomic absorption spectrometry (AAS) after dry ashing[6]. The obtained results give 1954 atoms per molecule Ferritin. It is in accordance with previous results, published by leading researchers [4,5]. The investigation of the iron content with AAS under the use of the Bulgarian standard is a good opportunity to study many other objects of biological interest. 1. J. McKnight, N. White and G. R. Moore, J. Chem. Soc., Dalton Trans.,4043-4045 (1997) 2. Kyung S. Kim et al., In.Ch. Acta, 298(1), 107-111 (2000) 3. J. L. Beard, J. W. Burton and E. C. Thiel, The J. of Nutrition, 154-160 (1996) 4. N.D. Chasteen and E. C. Theil, J. of Bio. Chem.,257(13), 7672-7677 (1982) 5. A. Treffry and P. 5. M. Harrison, Biochem. J.,171, , 313-320 (1978) 6.BDS EN 14082/2003 Foodstuffs - Determination of trace elements - Determination of lead, cadmium, zinc, copper, iron and chromium by atomic absorption spectrometry (AAS) after dry ashing.

ON ADSORPTION OF FERRITIN AND ALBUMIN ON GOLD SURFACE L. Vladimirova*, V. Savov University of Sofia “St. Kl. Ohridski” Dept. of Atomic Physics 5 J. Bourchier Blvd., 1164 Sofia, Bulgaria, [email protected] ABSTRACT The interaction of proteins with solid surface is a fundamental phenomenon with implication for biomaterials, biotechnological processes and nanotechnology. Quantification of adsorption and microstructural parameters of thin organic layers on planar surfaces is of high interest, especially in areas like biomaterials and surface-based biointeractions. The kinetics of adsorption of horse spleen ferritin and human serum albumin on gold (Au) surface was study with ellipsometry, electrochemical methods (impedance spectroscopy, cyclic voltammetry, redox titration), atomic absorption spectroscopy, atomic force microscopy etc. Received was the relation between parameters of adsorbed layer and pH, and protein concentration. The results suggest that the ferritin adsorption can be described as a multistage process while adsorption of albumin pass quickly during the first minutes, and measure up saturation. The data enable modelling of the protein adsorption on blood vessels and tissues in pathological processes.

POTENTIOMETRIC ASSESSMENT OF IRON RELEASE DURING THE FERRITIN REDUCTION BY EXOGENOUS AGENTS L. Vladimirova*, V. Kochev University of Sofia “St. Kl. Ohridski” Dept. of Atomic Physics 5 J. Bourchier Blvd., 1164 Sofia, [email protected] ABSTRACT Possibilities for quantitative determination of the iron mobilization connected with the ferritin reduction by ascorbic acid (Vitamin C) and sodium dithionite in vitro are investigated in the work. The iron-storage protein was incubated with 98

the excess of reductant in aerobic conditions without the presence of complexing agents in the medium. The release of Fe2+ was let to go to completion and the overall content of the Fe2+ in the solution was evaluated with the aid of potentiometric titration, using Ce4+ as an oxidizing titrant. The results suggest a moderate iron efflux under the action of the chosen reducing agents. While such a reduction of the protein mineral core by dihydroxyfumarate greatly contributes to the iron mobilization, the ferritin behavior to vitamin C and dithionite seems to be different. Although the redox properties of dihydroxyfumarate are determined by hydroxyl groups similar to these of the ascorbic acid, the two compounds differ significantly in structure, which could be the base for explanation of the specificities in their interaction with the ferritin. As revealed by the study, potentiometric titration is promising to be a reliable tool for the evaluation of the amount Fe2+ present in the solution as a result of the reduction of the ferritin’s mineral core.

ONE-COMPONENT NON-NECROTIC TUMOR. STATIONARY STATE AND LINEAR STABILITY ANALYSIS D. GRECU 1, A. S. CARSTEA 1, A. T. GRECU 1 1National

Institute of Physics and Nuclear Engineering “Horia Hulubei”, Bucharest, Romania

ABSTRACT The model proposed several years ago by Byrne and Chaplain (Math.Biosciences, vol 130, pag 151-181 (1995)) for a one-component non-necrotic tumor is extended in several ways. The stationary state is determined in the cases of spherical and ellipsoidal symmetric tumors. The linear stability of the stationary state is solved using usual mathematical methods, avoiding the complications of the full time dependend problem (a free boundary problem for a parabolic partial differential equation). Only the case of perturbations keeping the symmetry of the stationary state is discused.

HYDROGEN AND MATERIALS INFLUENCE OF THE HYDROGEN ENVIRONMENT ON THE METALLIC MATERIALS BEHAVIOUR Emil LAMANI, Patrice JOUINOT Polytechnic University of Tirana, Sheshi “Nënë TEREZA, Nr. 4, Tirana, Albania Supméca-LISMMA, Laboratoire de Physique des Matériaux, 3 rue Fernand Hainaut, F-93407, Saint Ouen, France ABSTRACT The embrittlement effect of the hydrogen on various materials is identified since a century, but criteria and methods for its characterization remain still object of intensive researches. The interest for such researches has increased recently, together with the safety increasing requests of the equipments and plants working in contact with gaseous hydrogen (pressure vessels, gas pipe-lines, pulse-jet engines etc.) and to the attempts for a larger use of this element as energetic vector. The materials sensitivity to hydrogen is studied and measured in this work using the disk pressure testing, introduced for the first time by the French nuclear centre (CEA). The disk testing principle is the comparison of the rupture parameters and the rupture surfaces obtained with metallic membranes tested similarly under helium and hydrogen. The specimen is an embedded disk (58 mm in diameter, 0.75-0.80 mm in thickness), loaded by a continuously increasing pressure of helium or hydrogen. The gas flow is regulated by pneumatic valves supervised by a PC-computer, allowing loading speeds from 10-2 to 2. 104 MPa/min. Macroscopic deformation is measured as the cupola deflection, side by side with the gas pressure, until the disk rupture. The disk and the loading cell can be heated up to 900o C with an annular furnace. The sensitivity to hydrogen is characterised by the embrittlement index, pHe/pH2, defined as the ratio of rupture pressures under helium and hydrogen. Such technique allows various studies and reveals parameters that remain not significant with less sensitive methods. This work presents an overview of numerous experimental results concerning the influence of different factors or parameters on the hydrogen embrittlement of ferrous and nonferrous alloys. These factors can be divided in two categories: the first one is related to the materials properties or attributes and includes the yield strength, the chemical composition, the mechanical and/or the heat treatments of the materials; the second one is related to the testing environment and includes the gas composition, the impurity content, the gas pressure and the temperature. There are some synergies between such 99

factors and the identification of various influences requires the interpretation of physical and metallurgical phenomena. On this basis practical consideration are made on the safety offered by different materials and on the criteria of their selection for applications including the hydrogen presence.

RADIOACTIVE AEROSOLS AS AN INDEX OF AIR POLLUTION IN THE CITY OF THESSALONIKI, GREECE A. Ioannidou* and C. Papastefanou *[email protected] Atomic and Nuclear Physics Laboratory, Physics Department, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece ABSTRACT Beryllium-7 is a cosmic-ray produced radionuclide with an important fraction of its production to take place in the upper troposphere. Once it is formed is rapidly associated with submicron aerosol particles and participates in the formation and growth of the accumulation mode aerosols, which is a major reservoir of pollutants in the atmosphere. Furthermore, the decay of 222Rn and 220Rn in the atmosphere produce low-vapor-pressure decay products that coagulate with other freshly produced nuclei or condense on accumulation-mode aerosols. This study summarizes results of an investigation done in order to find out how the radioactive aerosols could serve as indicators of air pollution conditions. Aerosol samplings, for measuring the activity concentrations of the short-lived 222Rn and 220Rn decay products, 214Pb (t1/2=26.8min) and 212Pb (t1/2=10.6h) respectively, were carried out every 3h in the open air (20 m above the ground, and 52 asl), at the Faculty of Science building in the centre of the city of Thessaloniki using a high volume air sampler. Comparison with the concentrations of cosmogenic 7Be (t1/2=53.3d) and gaseous air pollutants CO, NO, NOX, SO2 were made for relating diurnal variations of short-lived species with those of long-lived species that also participate in the aerosol dynamics. The aerodynamic size distribution of 7Be aerosols in different locations was obtained by using Andersen 1ACFM cascade impactor and the Activity Median Aerodynamic Diameter (AMAD) was determined. The concentrations of the short-lived radon decay products 214Pb and 212Pb in surface air during a day change considerably, with the higher values during the early morning, the lowest at noon and a slight increase in the afternoon. Comparison of 214Pb and 212Pb with gaseous air pollutants CO, NO, NOX, SO2 and total suspended particulate matter (TSP) revealed similar variations only with SO2 and TSP during the summer time probably reflecting the influence of the industrial pollution to the background of atmospheric air in the city of Thessaloniki. Thus, the atmospheric concentrations of radon decay products near the ground could be a useful index of air pollution potential conditions and transport processes in the boundary layer. Furthermore it is concluded that in the activity size distribution of ambient aerosols, 7Be changes to larger particle sizes in the presence of pollutants, since low AMADs of 7Be aerosols have been observed at low polluted locations.

A COMPARATIVE STUDY OF THREE SPATIAL INTERPOLATION METHODOLOGIES FOR THE ANALYSIS OF AIR POLLUTION CONCENTRATIONS IN ATHENS, GREECE Despina Deligiorgi, Kostas Philippopoulos, Lelouda Thanou and Georgios Karvounis National and Kapodistrian University of Athens, Department of Physics, Division of Environmental Physics - Meteorology ABSTRACT There are various methods available to perform spatial interpolation in estimating air pollutant concentrations at locations between monitoring stations. The most common methods include: Polygonal (Nearest Neighbor), Polynomial (Linear, Cubic), Splines (V4), Inverse Distance Weighted (IDW) and Kriging. The general theory behind spatial interpolation is the Tobler’s First Law of Geography — the closer together two points are in space the more likely those points are to be similar. The selection of the most appropriate method depends on the available data, the purpose of the analysis, and the intended use of the predicted surface. Knowledge about the data that are to be interpolated is critical to selecting an appropriate interpolation method and to understanding the results produced by the interpolation. In this paper, a detailed analysis of air pollutants concentration has been carried out with respect to spatial distribution of air pollutants concentrations monitored at seventeen stations scattered all over the city of Athens, Greece, for the period 2001 to 2005. These stations provide hourly data of six air pollutants: NO2, NOX, SO2, O3, CO and PM10. For the purpose of 100

this study the Polygonal (Nearest Neighbor), the Polynomial (Linear) and the Inverse Distance Weighted (IDW) methods were applied to these air pollution data. For the Polygonal (Nearest Neighbor) and Polynomial (Linear) methods the mean hourly concentrations of air pollutants were estimated and used, but for the Inverse Distance Weighted (IDW) method the mean monthly concentrations of air pollutants were estimated and used. The mean hourly concentrations of air pollutants were estimated for each site-station with the above three spatial interpolation’s methods and then the measured and estimated values of concentrations were compared. For each air pollutant, the time series of the measured and estimated concentrations, the relative scattered diagrams, the correlation coefficients and the statistical residuals were calculated for each method and they were compared. Finally, the ability and evaluation for all the methods to estimate urban, suburban and rural air pollution concentrations in broader area of Athens were analysed and discussed. The main conclusions for the Linear and Nearest Neighbor methods are: ➢ Linear method accomplished better estimation for each pollutant and station compared to the Nearest. ➢ Greater correlations coefficients occur for the pollutants NO2, NOx, O3, while smaller come for the case of SO2. ➢ For the stations located in the centre of Athens, the two methods give the same results for all the pollutants. ➢ For the stations located in the periphery of Athens, no one method can provide adequate results. ➢ For the PM10 and CO, the estimations are less adequate compared with the results for other pollutants. The main conclusions for the study of the mean monthly concentrations with the IDW method are: ➢ The models which achieve better fitting to the empirical variogram are the Gaussian, the Spherical and the Exponential. ➢ Greater R2 values appear for the NO2, NOx, SO2, O3 pollutants. ➢ The greatest R2 value for the IDW method shown for NO2. ➢ For the stations Liosia, Goudi, Pireas 1 and Nea Smirni the estimated values agree with the observed for more than one pollutant (NO2, NOX, SO2). For the stations Patision, Agia Paraskevi, Zografou and Thrakomakedones, there is not adequate estimation for more than half of the pollutants.The estimation of concentration is not adequate for the cases of PM10 and CO.

SEASONAL VARIATION OF INDOOR RADON IN ARTVIN-TURKEY Y.Ö. YE‹ILBAÒ, b. KÜÇÜKÖMERO ∏LU, A. KURNAZ, F. ÖZDERYA Erzincan University,Erzincan, Turkey, [email protected] Karadeniz Technical University,Trabzon, Turkey, [email protected] Karadeniz Technical University,Trabzon, Turkey, [email protected] Karadeniz Technical University,Trabzon, Turkey, [email protected] ABSTRACT Indoor radon studies have been conducted in Artvin, Eastern Black sea region of Turkey using SSNTD type nuclear track dedector (CR-39). Radon measurements were done for 4 seasons in 73 dwellings, selected as uniformly distributed as possible. The radon concentrations vary from 21 Bq m-3 to 321 Bq m-3 with the annual mean concentration of 132 Bq m-3 for Artvin. Seasonal variation indoor radon shows high in winter low values in summer. The resulting estimated annual effective dose-equivalent due to inhalation of radon for inhabitants is 3.32 mSv y-1 and the total annual effective dose lies in the range of the action level (3-10 mSv y-1) recommended by the ICRP.

SATELLITE REMOTE SENSING FOR SPATIO-TEMPORAL CHANGES ANALYSIS OF URBAN SURFACE BIOGEOPHYSICAL PARAMETERS Maria Zoran National Institute of R&D for Optoelectronics, Remote Sensing Dept., MG5 Bucharest-Magurele, 077125 Romania, ABSTRACT Early warnings of potential spatio-temporal changes in urban areas depend on key biogeophysical variables (such as land surface temperature, vegetation fraction, soil moisture, ground surface albedo, etc ) could enhance our ability to make better socio-economic decisions. The ability to translate current and projected variations in climatic and anthropogenic conditions of urbanized areas into ecosystem responses can provide valuable information to urban decision managers. The accuracy of such warnings depends on how well the past/present /future conditions of the ecosystem are characterized. 101

Recent advances in urban ecosystem modeling, internet based data delivery, and operational remote sensing products now allow us to simulate ecosystem processes in near-realtime. Spatio temporal changes in urban land cover (which is the biophysical attributes of the earth’s surface) and urban land use (the utilization of land for a given human purpose) have been reported to be the main driver of environmental change, while climatic change and climate variability may influence land-use preferences. Therefore accurate and up-to date information on urban land cover and the state of the environment is critical to urban environmental monitoring, management and planning. Remote sensing is a key application in global-change science for urban climatology and landuse/landcover changes analysis. Quantification of biophysical parameters is needed by terrestrial process modeling and other applications. Multispectral and multi-temporal satellite imagery (LANDSAT TM, ETM ; IKONOS,; MODIS ) over 1989 – 2008 period for Bucharest metropolitan area provide the most reliable monitoring technique of different urban structures regarding the net radiation and heat fluxes associated with urbanization at the regional scale. Bucharest City, the biggest industrial, commercial center in Romania experienced a rapid urban expansion during the last decades. A large amount of forest and agricultural land have been converted into housing, infrastructure and industrial estates. The resultant impervious urban surface alters the surface energy balance and surface runoff, which in turn could pose serious environmental problems for its inhabitants (e.g., urban waterlogged and thermal pollution).Investigation of radiation properties, energy balance and heat fluxes is based on satellite data from various satellite sensors and in-situ monitoring data , linked to numerical models and quantitative biophysical information extracted from spatially distributed data and net radiation. Based on satellite imagery data, this research developed an analytical procedure based upon a spectral unmixing model for characterizing and quantifying spatio-temporal changes in Bucharest metropolitan area, Romania, and for examining the environmental impact of such changes on urban biogeophysical parameters. The changes over the years of surface biophysical parameters are examined in association with landcover/landuse changes to illustrate how these parameters respond to rapid urban expansion in Bucharest and surrounding region. For detailed landuse classifications in a digital form these properties were analyzed in a statistical way .This study attempts to provide environmental awareness to urban planners in future urban development. The land cover information, properly classified, can provide a spatially and temporally explicit view of societal and environmental attributes and can be an important complement to in-situ measurements. Also, this information provides a perspective for understanding factors potentially mediating the interactions between urbanisation and variations of environmental quality. Keywords: Environmental physics, urbanization, satellite remote sensing, surface biophysical parameters, spatiotemporal changes, Bucharest.

ELECRTOMAGNETIC PRECIPITATORS Electromagnetic Precipitators for protection from chimney exhaust gases which pollute the atmospheric air By: Dimitrios Dellaportas Technology Mechanical Engineering, Pedagogic, Ms. of Physics, Principal of 1st EPAL (School ) of Pireas Greece, TEL: 210 – 4135689, 210 – 4824277, Mobile: 6974124184 email: [email protected] We will try to touch two cases of a central heating chimney. The first, it has circular profile and the second, with rectangular profile. Inside the chimney, on sharp points of electrodes, the electric field may become very high. Although, air is usually regarded as an nonconducting matter, it does contain ions produced by cosmic rays above and radioactivity from the earth below. So, a charged electrode with sharp point will attract ions of opposite polarity. The attractive force, F=e.E, (e=ion charge and E=field) accelerates the ions to velocities which may result in the production of more ions by collision (avalanche effect). These ions flowing between electrodes constitute and electric current (corona discharge phenomenon) with visible glow and an audible hissing sound. We can supply this current to electrodes by a photovoltaic panel that is placed near the chimney. This effort, will has important andvantages for the environmental protection, and economy related to electric current production. References Elliott R. S. “Electromagnetics” McGrow-Hill, N.Y. 1966 Halliday D. , Resnick R. “Physics” Wiley, N.Y. 1978 Joos G, Freeman Ira “Theoretical Physics” 3rd Edition , Dover Publication 1986 Serway R. “Physics” for Scientists and Engineers, 3rd Edition 1990

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AN OBSERVATIONAL STUDY OF THE URBAN HEAT ISLAND IN THE GREATER THESSALONIKI AREA Preliminary results and development of a forecasting service Giannaros 1 , T.M., Melas 1 , D., Kontogianni 1 , P. Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki ABSTRACT The city of Thessaloniki, located at the North-East part of the Thermaikos Gulf, is the second largest city of Greece with an estimated population of 800,000 habitants. The east part of the city is surrounded by the Hortiatis mountain, 1,200m high, while the western side of it, is an extended flat area where the industrial zone of Sindos is present. The city is influenced by the sea to the south. As a result of its complex topography, the city of Thesaloniki is subject to a rather complex micro-climate, experiencing significant variations in its ventilation patterns even over small distances. Such variations may lead to increased air temperatures in several areas of the urban agglomeration, in comparison with air temperatures observed at sub-urban areas around the city. This phenomenon, which is widely known as the “urban heat island” (UHI), is considered to be one of the most representative and well documented manifestation of urban climatic modification. The UHI is present in every town and city around the world and is the most obvious climatic indication of urbanization. Recently, the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki (LAP-AUTH) has installed a temperature monitoring network in the greater Thessaloniki area (GTA). The network consists of 9 HOBO-U23 data logging devices, which are used to measure air temperature and relative humidity in the urban canyons and other urban and sub-urban sites in the GTA. At each site, the logging devices have been placed in a white shield in order to protect the instruments from solar radiation and rain. One of the temperature and relative humidity sensors has been calibrated by the Hellenic Metrology Institute (HMI) and its calibration certificate has been used for inter-calibrating the rest of the sensors. The meteorological shelters have been placed 3-5m above the ground in suitably selected measurement locations, in and around the urban core of the city of Thessaloniki. The main purpose of the current paper is to present results from the operation of the LAP-AUTH temperature monitoring network in the GTA. Temperature readings referring to the Summer Period (July and August, 2008) and the Summer Transitive Period (June and September, 2008) are presented and discussed in combination with the application of various statistical tests. From this study, it is mainly observed that the centre of the city of Thessaloniki develops the heat island effect more intensively during the nighttime. Moreover, in order to account for the effect of the heat island on human comfort, we calculated the discomfort index (DI) for the above mentioned time periods. Finally, we introduce the development of a European UHI forecasting service, in the frame of the “Urban Heat Islands and Urban Thermography” project that is funded by the European Space Agency (ESA-21913/08/I-LG). In the frame of this project, LAP-AUTH has been delegated to develop a service that will operationally deliver UHI-related forecast products (i.e. air temperatures, discomfort indices etc), on a daily basis, to several end-users across Europe. The current paper presents the aspects of this service, along with some prototype products for the city of Athens.

OXOBIODEGRADABLE PLASTICS AS PACKAGING MATERIALS:A STEP TOWARDS SUSTAINABILITY Nikos Katsaros Institute of Physical Chemistry, NCSR “Demokritos”, 15310 Ag. Paraskevi, Athens Greece tel.: +302106503645, fax: +302106511766, e-mail: [email protected] Plastic is a familiar component of modern living, used in all sorts of packaging and household and commercial applications. Whilst the benefits of low cost, light weight, strength, imperviousness to gas and water, transparency, sealability, and printability are highly regarded, the very strength and durability which makes plastic such a useful and economic material becomes a major problem when disposal is required. Science has now found the answer to this problem. The most useful and economic of the new technologies produces plastic which degrades by a process of oxodegradation. This technology is based on a very small amount of a pro-degradant additive being introduced into the conventional manufacturing process, thereby changing the behavior of the plastic. The degradation of the plastic starts immediately after manufacture and will accelerate when exposed to heat, light or stress. It will be consumed by bacteria and fungi after the additive has reduced the molecular structure to a level which permits living 103

micro-organisms access to the carbon and hydrogen. It can therefore be properly described as “biodegradable”. The material has then ceased to be a plastic and has become a food source. This process continues until the material has biodegraded to nothing more than CO2, water, and humus. It does not leave fragments of petro-polymers in the soil. There is little or no additional cost involved in products made with this technology. The length of time it takes for oxobiodegradable plastic products to degrade can be programmed’ at the time of manufacture and can be as little as a few months or as much as a few years. They can be opaque vacuum-packed for delivery and will not degrade in the absence of air and light, until needed for use. Unlike PVC, the polymers from which oxobiodegradable plastics are made do not contain organo-chlorine. Nor do oxobiodegradable polymers emit methane or nitrous oxide under aerobic or anaerobic conditions. Policymakers need always to consider what happens to waste plastic products which escape the collection net and end up as litter. It is impossible for industry and government to ensure that they are all collected, and even if collected to ensure that they are all recycled or incinerated. They should all therefore be made from oxobiodegradable plastic, except for very long-life items. If collected they can be recycled, composted, or incinerated, and if not collected they will degrade and disappear, leaving no harmful residues. Products can be made in oxobiodegradable plastic using the same machinery as currently used for conventional plastic. There is therefore no need to reequip factories or retrain the workforce. As the labor, cost, and energy required to produce the raw material for oxobiodegradable plastics is going to be incurred anyway in the production of fuels, it cannot properly be attributed to oxobiodegradable plastics in a Life-cycle Assessment.

COMPARISON OF SATELLITE NO 2 OBSERVATIONS WITH HIGH RESOLUTION MODEL SIMULATIONS OVER THE BALKAN PENINSULA I. Zyrichidou 1, M. E. Koukouli 1, D. S. Balis 1*, E. Katragkou 1, A. Poupkou 1, I. Kioutsioukis 1, K. Markakis 1, D. Melas 1 , R. van der A 2, F. K. Boersma 2 and M. van Roozendael 3 Laboratory of Atmospheric Physics, Physics Department, Aristotle University of Thessaloniki, Thessaloniki, Greece 2 Royal Netherlands Meteorological Service, De Bilt, The Netherlands 3 Belgian Institute for Space Aeronomy, Brussels, Belgium ABSTRACT 1

High resolution model estimations (10x10km) of tropospheric NO2 column amounts from the Comprehensive Air Quality Model (CAMx) were simulated for the Balkan Peninsula and were compared with satellite data for a period of one year, in order to study the characteristics of the spatial and temporal variability of pollution in the area. The Balkan area is considered a crossroad of different pollution sources and therefore has been divided in urban, industrial and rural regions, aiming to investigate the consistency of satellite retrievals and model predictions at high spatial resolution. Satellite measurements of tropospheric NO2 are available daily at 13:30 LT since 2004 from OMI/Aura with a resolution of 13x24km. The anthropogenic emissions used in CAMx for the domain under study, was compiled employing bottom-up approaches (road transport sector, off-road machinery) as well as other national registries and international databases. High resolution GIS maps (road network, landuses, population) were also used in order to achieve high spatial resolution. In most of the cases the model reveals similar spatial patterns with the satellite data, while over certain areas discrepancies were found and investigated.

GEOENGINEERING AND THE GREENHOUSE EFFECT Nikos Katsaros Scietific collaborator NCSR “DEMOKRITOS” The National Academy of Sciences {USA}defined geoengineering as .Several geoengineering projects have been proposed.These projects either reflect the solar radiation thus reducing the temperature increase or traping the carbon dioxide with the same result. Solar radiation management projects include: 1.creating stratospheric sulfur aerosols 2.cool roof-using pale-coloured roofing and paving materials 104

3.cloud reflectivity enhacement –using fine sea water spray to whiten clouds and increase cloud reflectivity. 4.space sunshade-obstructing solar radiation with space-based mirrors or other structures(planetary dimming) Greenhouse gas remediation. Techniques in this category include: 1.iron fertilization of the oceans. 2. Trapping carbon dioxide by chemical means and storing it in terra preta. 3.carbon air capture to remove carbon dioxide from ambient air’ To date,no large scale geoengineering projects have been undertaken,nor has a consensus been reached that geoengineering is desirableThe scientific community suggests that geoengineering it threatens to reduce the political and popular pressure for emissions reduction.Some scientists suggest that geoengineering strategies is not an alternative to emissions control but rather an accompanying strategy.The geoengineering experiments may cause undesirable effects to the environment.The increase of carbon dioxide in the oceans will alter the pH of sea water with severe alteration of the marine eco-system.Managing solar radiation using aerosols or cloud cover will change the ratio between the direct and indirect solar radiation.This may affect plant life,and solar energy.Aerosols may affect formation of clouds,especially cirrus clouds. Weaponization of geoengineering techniques is generally prohibited by the Enviromental Modification Convention.However this does not eliminate the risk.Geoengineering techniques may be used as a weapon of mass destruction,creating droughts or famines designed to destroy or disable an enemy.

SUSTAINABLE DEVELOPMENT AND PROTECTION OF THE ENVIRONMENT: TWO MANAGEMENT STRATEGIES NOT ALWAYS COMPATIBLE Dr Artemios M. Athanassakis, ª.Sc., M.Ed. Department of Education in -Service Training, University of Athens ABSTRACT The definition of Sustainable Development has received intense criticism and contestations with the result, that International Union for the Conservation of Natural Resources (I.U.C.N.), and the World Wide Fund for Nature (W.W.F.) clarified that sustainable development means the improvement of life quality, inside the limits of clarified capacity of ecosystems. According to its critics, is considered as a general concept, indefinite and contradictory. Those disputes put the accent on the close relation between the Sustainable Development and the values of the today’s global market. This relationship transforms the Sustainable Development to an one dimensional economical growth with the “ecological ornaments” of sustainability and protection of environment. Therefore this paper looks for, whether the sustainable development consists one more device, focuses on the world financial system, or establishes one optimistic developmental perspective, which might harmonize the economical activities with the natural function of our planetic ecosystems. Keyword: Sustainable Development, Economical Growth, Natural Resources.

GROSS ALPHA BETA RADIOACTIVITY IN AIR FILTERS MEASURED BY ULTRA LOW LEVEL ·/‚ COUNTER INTERNATIONAL COMPARISON ORGANIZED BY IAEA 2008 Florinda Cfarku*. Elida Bylyku* & Antoneta Deda** *Centre of Nuclear and Applied Physics, Faculty of Natural Sciences, University of Tirana, Albania P. O. Box 85, “Qesarak” street, Tirana. ALBANIA. Tel.: & Fax: + + 355 42 362 596. ** Department of Physics, Faculty of Natural Sciences, University of Tirana, Albania E-mail: [email protected] ABSTRACT Study of radioactivity in air as very important for life is done regularly using different methods in every country. As a result of nuclear reactors, atomic centrals, institutions and laboratories, which use the radioactivity substances in open or closed sources, there are a lot radioactive wastes. Mixing of these wastes with rivers and lakes waters makes very important control of radioactivity. At the other side nuclear and radiological accidents are another source of the contamination of air and water. Due to their radio toxicity, especially those of Sr90, Pu239, etc. a contamination hazard for human begins exist 105

even at low concentration levels. Measurements of radioactivity in air have been performed in many parts of the world mostly for assessment of the doses and risk resulting from consuming air. In this study we present the results of international comparison organized by IAEA Vienna, Austria for the air filters spiked with unknown Alpha and Beta Activity. For the calibration of system we used the same filters spiked: a) with Pu-239 as alpha source; b) Sr-90 as beta source and also the blank filter. The measurements of air filter samples after calibration of the system are done with Ultra Low Level ·/‚ Counter (MPC 9604). The high sensitivity of the system for the determination of the total alpha and beta activity makes sure detection of low values activity of air filters. Our laboratory results are: A· = (0.19 ± 0.044) Bq/filter and A· (IAEA) = (0.17 ± 0.009) Bq/filter; A‚ = (0.33 ± 0.098) Bq/filter and A‚ (IAEA) = (0.29 ± 0.01) Bq/filter. As it seems our results are in good agreement with reference values given by IAEA (International Atomic Energy Agency).

OPTIMIZATION OF EOSINE SPECTRAL DETERMINATIONS IN WATER SAMPLES Liljana Kola Center of Applied Nuclear Physics; PO. Box 85, Tirana, Albania, [email protected] ABSTRACT The fluorescence ability of Eosine enables its using as artificial tracer in the water system studies. This fact is dealt with in relation to applying Eosine to trace and determine water movements within the karstic system and underground waters. The fluorescence intensity of fluorescent dyes in water samples depends on their physical and chemical properties, such as pH, temperature, presence of oxidants, UV radiation, etc. This paper presents the results from studying the influence of the properties mentioned above on Eosine fluorescence intensity, so it gives the experience of the Center of Applied Nuclear Physics, Tirana in this field. We have used for this study the standard solutions of Eosine. The synchronous scan and concentration methods we have elaborated to this purpose made it possible to optimize procedures we use to analyse water samples for the presence of Eosine and measure its content, even in trace levels, by the means of a Perkin Elmer LS 55 Luminiscence Spectrometer.

MONITORING OF THE DRINKING WATER QUALITY USING ALTERNATIVE ANALYTICAL TECHNIQUES G.V.Cimpoca1, C.Radulescu 2National

, I.D.Dulama 1 ,I.V.Popescu1, C.Stihi1, A.Gheboianu M.Cimpoca 2 , I.Cernica 2

1

1

, I.Bancuta 1, I.Ionita1

1Valahia State University of Targoviste, 130024 Targoviste, Romania Institute for Research and Development in Microtechnologies, 023573 Bucharest, Romania

ABSTRACT In this paper we study the drinking waters qualities with Quartz Crystal Microbalance (QCM), Atomic Absorption Spectrometry (AAS) and classical analytical methods (pH, conductivity/resistivity, TDS, salinity). Our studies present a new application of quartz crystal microbalance (QCM) for measure and identify trace quantities of metals and volatile organic compounds (VOCs) in water comparative with AAS and other methods. QCM was adapted for many different uses by developing coatings that respond to different target molecules. Also, to evaluate the utility of QCM sensors to detect a range of VOC contaminants, some compounds was tested: Polar VOCs - acetone, isopropanol, ethylene glycol and ethyl acetate; Nonpolar VOCs - xylene, toluene; Chlorinated hydrocarbons - trichloroethylene (TCE) and tetrachloroethylene (PCE). A typical experimental run use deionized (DI) water and a water sample contaminated with successively higher concentrations of impurities. The ability to provide real-time monitoring of chemical contaminants in water samples can be used for a variety of applications: on-line monitoring of contaminants in process, recycle, and waste water; groundwater quality monitoring; detection of contaminants in streams, lakes and water supplies; monitoring dumping in off-shore waterways.

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Keywords: Quartz Crystal Microbalance, Newtonian liquids, solid/fluid interfaces Dickert, Fl., Lieberzeit, P., Hayden, O., Analytical and Bioanalytical Chemistry, 377(3), 540-549, 2003. Marx, K.A., Biomacromolecules, 4(5), 1099-1120, 2003. Si, P., Mortensen, J, Komolov, A., Denborg, J., Moller, P.J., Analytica Chemica Acta, 597(2), 223-230, 2007. Consales, M., Campopiano, S., Cutolo, A., Penza, M., Aversa, P., Cassano, G., Giordano, M., Cusano, A., Sensors and Actuators B: Chemical, 118(1-2), 232-242, 2006. Auge, J., Hauptmann, P., Eichelbaum, F., Rosler, S., Sensor and Actuators, 18-19, 518-522, 1994. Rodriquez-Pardo, L., Farina, J., Gabrielli, C., Perrot, H., Brendel, R., IEEE Sensors Journal, 5(6), 1251-1257, 2005.

QCM REAL-TIME SENSOR FOR MONITORING OF POISONOUS CYANIDE FROM DRINKING WATER AND ENVIRONMENTAL G.V.Cimpoca 1, C.Radulescu1, I.D.Dulama 1 ,I.V.Popescu 1, A.Gheboianu, I.Bancuta 1, M.Cimpoca 2, I.Cernica 2, L.Staicu 2 2National

1Valahia State University of Targoviste, 130024 Targoviste, Romania Institute for Research and Development in Microtechnologies, 023573 Bucharest, Romania

ABSTRACT In this paper we study the waters qualities with Quartz Crystal Microbalance (QCM) from diverse mediums: drinking waters, industrial waters, mainstream and groundwater’s for to protect the population health and the environment. Our studies present QCM real-time sensor is for monitoring of poisonous cyanide at both drinking water standard and environmental regulatory concentrations. Through the use of a flow cell, aqueous samples containing cyanide are reacted with a gold electrode of a piezoelectric crystal to indirectly sense cyanide concentration by the dissolution of metallic gold. The quartz crystal is an AT-cut wafer, 5 MHz resonance frequency, 14 mm2 active areas, CrAu or TiAu electrode metallization. We use QCM with the liquid flow cell. The debits of liquid were varied between 0.1 ml/min. and 1 ml/min. The presence of cyanide in solution results in the selective formation of a soluble dicyano-gold complex according to the Elsner reaction [1]: 4Au + 8CN- + 2H2O + O → 4Au(CN)2 - + 4OH-. The resulting loss of gold from the electrode is detected by the piezoelectric crystal as a resonant frequency change f and resitivity change R. Since free cyanide is a weak acid (pKa 9.3), available protons compete for cyanide ligands. Therefore, increased sample pH provides higher sensitivity. The detection limits at pH 12 are about 50 ppb for analysis times of 10 min, and 10 ppb for analysis times of 1 h. The incorporation of the flow cell improves both analyze sensitivity and instrument precision, with an average signal intensity drift of only 5% over a 1h analysis. The calibrations show excellent linearity over a variety of cyanide concentrations ranging from low ppb to hundreds of ppm. The developed detection system provides rapid cyanide determinations with little sample preparation or instrument supervision.The ability to provide real-time monitoring of chemical contaminants in water samples can be used for a variety of applications: on-line monitoring of contaminants in process, recycle, and waste water; groundwater quality monitoring; detection of contaminants in streams, lakes and water supplies; monitoring dumping in off-shore waterways. Keywords: Quartz Crystal Microbalance, sensor, cyanides, environmental 2

Rodriquez-Pardo, L., Farina, J., Gabrielli, C., Perrot, H., Brendel, R., IEEE Sensors Journal, 5(6), 1251-1257, 2005. [12] Timofeyenko, Y.G., Rosentreter, J.J., Mayo, S., Anal. Chem., 79, 251-255, 2007. Nelson Nunalee, F., Shull, K. R., Lee B. P., Messersmith, P. B., Anal. Chem,. 78,1158-1166, 2006

INDOOR AND OUTDOOR GAMMA DOSE MEASUREMENTS FOR SPECIFIC COUNTIES OF TRABZON-TURKEY A. KURNAZ a, B. KÜÇÜKÖMERO ÒLUa and N.T. OKUMU }OÒLU b a Karadeniz

Technical University, Department of Physics,Trabzon, TURKEY University, Department of Physics,Rize, TURKEY

b Rize

ABSTRACT In this study, it was determined environmental gamma radiation dose rate for some counties of Trabzon-Turkey. A detailed ambient gamma dose measurement has been performed in the seven counties of Trabzon, using a portable 107

environmental survey meter (NaI detector, INSPECTOR 1000). The measurements were performed indoor and outdoor of buildings and also at each spot, a reading was taken at 1 m above ground level. The dose rates varied from 42.69 nGy/h and 140.91 nGy/h for indoor gamma dose and 27.84 nGy/h and 121.80 nGy/h for outdoor gamma dose . Average indoor and outdoor gamma dose rates were ascertained to be 71.05 nGy/h and 60.20 nGy/h, respectively. The annual effective doses were calculated from indoor and outdoor gamma doses to be 348.56 ÌSv/y and 73.83 ÌSv/y, respectively.

CORRELATION BETWEEN OPTIMAL SWELLING MODEL IDENTIFICATIONS AND STRUCTURAL – MINERALOGICAL DATA OF SOME PRE –ADRIATIC ALBANIAN DRILLING MUDS Marie DEDE 1, Fatmir SHEHU 2, Bashkim ÇELA 3, Bardhi GUDA

4

2 Construction materials_65 1Department of Physics, Faculty of Natural Sciences, University of Tirana, Company, Tirana, 3Faculty of Geology, University of Tirana, 4Department of Physics, Faculty of Natural Sciences, University of Tirana ABSTRACT

Identifying the swelling model of clays under the influence of the active phase of drilling fluids is important in determining their interaction with particular clay minerals which are exposed to the walls of the well. The necessary time of maximal swelling of an ingredient of drilling mud (clay, polymer, filler etc.) has a specific degree which is often relatively long. If the porous layer is introduced to a clay material which has not reached maximal swelling, it is understandable that in a rock, along with the continuing swelling of the introduced material, supplementary tensions are created which modify the tensioned condition of the rock. On the other hand, materials which have not completed the full swelling cycle, introduced to the productive layer of oil/gas well and retaining water, will act as “blocking” agents during the continuing swelling process; this will bring unsatisfactory consequences during the escape of industrial fluids from the layer in wells during the assimilating and consuming phase. The study argues that the drilling technology should take into account the clay structure of the well and the time it takes to achieve maximal swelling of particular clay in a particular environment. The swelling characteristics of some Tortonian formations of pre-Adriatic regions compared with smectite clays of Prrenjas region and are identified based on the kinetic laws of swelling. To predict the swelling model of compacted clay, equations for evaluating the content of swelling clay mineral in the compacted clays’ phase are used, as well as the computing the ion concentration of pore water which significantly influence the swelling characteristics. The tests were carried out under the influence of different reactive solutions (CaSO4, CaO, CaCl2, NaCl, KCl) which have simulated the filtration of drilling fluid used most often in the drilling technology. The swelling characteristics are confirmed by liquid and plastic limits. The swelling model depends on the clay structure of which the active solutions are prepared and with which the clay interacts. The analysis is supported by associations of chemical, rheological data (Bingam) CEC (~ 60 mgr.eq/100g) and the pore pressure gradient (~2.2-2.3 gr/cm3). The structural specifications by XRD, DTA and IR techniques are used for confronting the mineralogical data of used type of clays. The presence of the XRD peak of 14.4 A, an exothermic DTA peak of 830-890 oC and the IR band 930cm1 – 827cm-1 are among the indicators of the dioctahedral composition of the montmorillonite phase; the swelling affects also the frequencies of the Si -O absorption bands in the 1000-1100cm-1. The intensity of the band in the Si-O region of spectrum progressively increases with decrease in swelling. The overall decrease in the absorption bands in the Si-O region with swelling is expected due to the decrease in clay mineral content with increased hydration. The most confident swelling models are evaluated (exponential, B=0.550exp0.00093T; logarithmic (-9.8266+4.489lnT) and linear B=10.5251+0.288T) and the correlation coefficients models are made evident (respectively 0.981, 0.996, 0.743). According to the identified models, the swelling varies in relation to controlling cations of active fluids with which the clay interacts. The good influence had the presence of K-ion. It appears that some clays of pre-Adriatic region with a significant o quantity of dioctahedral montmorillonite phase (~ 35%, d 001 peak_14Ao,) and then kaolinite (22%, and chlorite (~15%, d 003 o o peak_4.7Ao, and d001 sharp peak about 1Ao, ) have a “zero” swelling time, which means that as soon as they come to contact with the reactive environment they swell instantaneously.

108

RESULTS OF THE NATIONAL SURVEY ON RADON INDOORS IN ALBANIA STUDY OF RADON LEVELS IN REPRESENTATIVE REGION K. Bode*, E. Bylyku*, F. Cfarku*, I. Mocollari*, M. Shyti* *Centre of Applied Nuclear Physics, Faculty of Natural Sciences, University of Tirana, Albania. P.O.Box 85, ’Qesarak” street, Tirana, Albania. Email: [email protected] ABSTRACT Radon in indoor air originates from trace concentrations of radium in substrate soil and the walls, floor and ceilings which are constructed of building materials. According to the assessments made by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), radon in the natural environment constitutes about 50% of the human exposure to natural radiation or 1,2 mSv/year. In this paper are given the results of the indoor radon concentration measurement of about 173 dwellings which involving 10 Albanian Regions performed by the Centre of Applied Nuclear Physics. For these measurements were used passive radon detector Radtrack, which provide the average values of indoor radon concentration for 90 days (3 months). Regional averages range from about 23 Bq/m 3 to about 278 Bq/m 3. However, the uncertainty of regional values can be relevant in case of small Regions, where a low number of small dwellings, although such uncertainties do not affect significantly national values. Based at the results of the measurements, the indoor radon concentrations in the majority of the dwellings were under reference levels (200-400 Bq/m3).

THE MEASUREMENT OF BACKGROUND IN THE SALT MINE PRAID WITH A TLD SYSTEM A.I.Stochioiu, M.C.Sahagia, I.L.Tudor “Horia Hulubei” National Institute of Physics and Nuclear Engineering (IFIN-HH), 407 Atomistilor Street, PO Box MG-6, Magurele, Ilfov County, RO-077125, Romania ABSTRACT This paper presents the results obtained in the monitoring of the low level background in a Romanian salt mine, proposed to be used as an underground accelerator lab [1] using a high sensitivity TLD system, as an extension of our previous monitoring of another mine [2], by using the same type of TLDs. The paper reports the experimental procedure, consisting from the choose of key points to be monitored and of the optimum period for continuous registration, as well as the processing of data . The values of the background level, expressed in terms of ambient dose equivalent rate (nSv h1), are reported. The correlation of this method results with those obtained by using the most elaborated gamma-ray spectrometry is satisfactory. This method is much more accessible and allows for the continuous monitoring of the area. [1] C.Bordeanu, C.Rolfs, R.Margineanu, F.Negoita, C.Simion. “Saltmine underground accelerator lab for nuclear astrophysics”. J.Phys. G:Nucl. Part. Phys. 35(2008)014011 [2] A.Stochioiu, M. Sahagia, F. Mihai, I.Tudor, H.Lupescu “Application of the thermoluminescent dosemeters for the measurement of low level background”, AIP Conf.Proc.899 ,2007, pp.413-414

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PARTITIONING GLOBAL SOLAR RADIANT FLUX INTO ITS SPECTRAL UVB AND UVA COMPONENTS UNDER VARIOUS ATMOSPHERIC CONDITIONS AT ATHALASSA, CYPRUS Chrysanthou A.S., Jacovides C.P., Asimakopoulos D.N. University of Athens, Department of Environmental Physics & Meteorology University Campus, Builds PHYS-V, Athens 15784, Greece ABSTRACT Elevated solar ultraviolet radiation associated with stratospheric ozone reduction may exert significant increases in the UV radiant flux reaching the ground surface mainly in the UVB (280-315 nm) spectral portion. This study aiming to explore the UV radiant flux levels in the eastern Mediterranean belt, hourly measurements of global UVB (Guvb), UVA (G uva) and broadband (G h) radiant fluxes collected at Athalassa, Cyprus (350N, 330E, 165 m above MSL) from 1 January 2004 to 31 December 2006, during a joint research project between the Athens University and the Meteorological Service of Cyprus, are employed. These data were used to determine temporal variability of the UV radiant components further addressing their dependence on sky conditions and several other atmospheric parameters. Further, in order to include the ozone column amount and solar zenith angle cycles, the experimental UV data were normalized to the 3-year (2004-06) monthly mean climatological values of both ozone and zenith angle. In this study, the simple linear relation Y=·X between the radiant fluxes was further engaged. The analyses of hourly spectral UVB and UVA values revealed significant diurnal variation of these radiant fluxes during daylight hours. The seasonal variation of the radiometric ratios obtained from hourly correlations, ranged from 0.0297±0.004 (winter) to 0.0315±0.003 (autumn) with an annual mean of 0.0308±0.003 for (G uva/Gh), and from 0.00158±0.0005 (winter) to 0.00167±0.0003 (autumn) with an annual mean of 0.00163±0.0004 for (Guvb/Gh). The hourly radiometric ratio (Guva/Gh) increased from 0.0304±0.003 to 0.0322±0.003 as sky conditions changed from clear to overcast skies; the hourly radiometric (Guvb/Gh) ratio also increased from 0.00161±0.0003 to 0.00172±0.0004, as sky conditions changed from clear to overcast skies.

ONLINE MONITORING AND DETERMINATION OF ENVIRONMENTAL DOSE RATE, USING RADIOLOGICAL NETWORK, IN ALBANIA Ervis Telhaj

1

and Antoneta Deda

2

1 Center 2

of Nuclear Physics, Faculty of Natural Sciences, University of Tirana, Albania Department of Physics, , Faculty of Natural Sciences, University of Tirana, Albania

ABSTRACT From May 2004, in the Center of Nuclear Physics in Tirana, in the framework of emergency monitoring. in Albania, .is installed Radiological Monitoring Network.. In this network, which is unique on-line monitoring system in our country. are included 5(five) monitoring stations, respectively in Tirane, Shkoder, Kukes, Korce and Vlora. The last four stations are near Albanian borders The network, performs measures of environmental dose rate. in a range from 5 nSv/h up to 10 Sv/h. Working detector of type VACUTEC 70045 A. are calibrated using standard radiation source Cs-137. This monitoring helps in information in real time in a case of radiological accidents of 5th degree (for example accidents in nuclear power plants, near Albanian territory, loss control, relation to powerful radiations, etc. ) In this paper are brought the data about national network of emergency, available detectors of dose rate, the technical concept, program of the work, measurements and their interpretations.

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ENVIRONMENTAL CHANGES ASSESSMENT OF COASTAL ZONES BY FUZZY SET THEORY Liviu Florin Zoran

1

, Carmen Ionescu Golovanov 1, Maria Zoran

2

1

University Politehnica of Bucharest, Electrical Engineering Faculty, Electrical Measurements Dept., Bucharest 77206, Romania; 2 National Institute of R&D for Optoelectronics , Remote Sensing Dept. , MG5 Bucharest Magurele, 077125 Romania. ABSTRACT Environmental changes and climate-induced changes at the land-sea interface (e.g., through more intense and higher frequency droughts, flooding events) may in turn feed back on the climate itself, for example, through changes in soil moisture, vegetation, radiative characteristics, and land –sea surface-atmosphere exchanges of water vapor. Fuzzy theory applied for the analysis of coastal areas analysis of changes , in which each pixel on the map is assigned a membership grade in all classes, are reasonable alternatives to traditional fixed classifications. Mixture modeling and subpixel spectral analysis is used for assessment of the percent cover of individual cover types within a pixel. These methods require a definition of spectral endmembers, which is difficult (and perhaps impossible) for complex and highly variable land cover units. Fuzzy classifications and mixture/subpixel models provide information on variations in spectral signature between pixels and not on differences in the on-the-ground content of mapped land cover. The coastal zone units are recognized on a ground truth map of an area using Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) as well as SAR ERS-1 imagery for North-Western Black Sea coastal zone ,Romania, over 1989-2008 period .For assessing spatial patterns of changes, has been applied change vector analysis . Keywords: environmental changes, fuzzy theory, Black Sea coastal zone, satellite data.

A PHENOMENON OF SECULAR AUTUMN TEMPERATURE DECREASE IN STARA ZAGORA, BULGARIA Nikolay Petrov Takuchev Trakia University, Stara Zagora, Bulgaria ABSTRACT A negative trend of the average autumn temperature in the region of Stara Zagora, Bulgaria for the last 109 years was found. The autumn temperature was calculated from data in ten-day average temperatures for the period of astronomical autumn - from the last ten-day period of September to the second ten-day period in December. There is literature confirmation that such decrease of autumn temperatures was found elsewhere in Bulgaria. Dependence between a series of average autumn temperature and several climatic indices was sought for an explanation of this phenomenon. Significant negative correlation of average autumn temperature with increasing branch of the cycles of solar activity over the same interval of time was found.

THE MOSS TECHNIQUES FOR AIR POLLUTION STUDY IN BULGARIA S. Marinova*, M. Frontasyeva**, L. Yurukova***, L. Strelkova**, A. Marinov* *Department of Physics, University of Plovdiv, 24 TzarAssen Str., 4000 Plovdiv, Bulgaria, [email protected] **Joint Institute for Nuclear Research, 6 Joliot Curie Str., 141980, Dubna, Russia ***Institute of Botany, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 23, 1113 Sofia, Bulgaria ABSTRACT The moss biomonitoring technique was used to study trace element atmospheric deposition in four areas of Bulgaria (the Western Thracian-Rhodope, the Eastern Thracian-Rhodope, the South-Eastern and the North-Central areas) during the European moss survey in 2005. A total of 41 elements (Na, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rd, Sr, Mo, Cd, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Tb, Dy, Tm, Yb, Hf, Ta, W, Au, Pb, Th, and U) were determined by instrumental epithermal neutron activation analysis and atomic absorption spectrometry in 99 moss samples. The dominant moss species was Hypnum cupressiforme. Principal component analysis (factor analysis) was used to identify and 111

characterize different pollution sources and to point out the most polluted areas The interpretation of the factor analysis findings points to natural crust, marine, and vegetation components as well as to anthropogenic sources: ferrous (Plovdiv, Haskovo) and non-ferrous industries (Plovdiv, Kardzhali, Burgas), oil refining (Burgas), and central heating stations (Plovdiv, Haskovo, Stara Zagora, Burgas). Comparison of the obtained levels of elemental concentrations in two sequential moss surveys in 2000 and 2005 showed that the median values of concentrations of such elements as Cr, Co, Se, and W increased, that reflects a clearly marked trend for increase of the industrial activity in Bulgaria since 2000. Comparison of the medians of the elemental concentrations in moss samples collected in Bulgaria with those in the Balkan and other European countries revealed the geochemical peculiarities of the Balkans for such elements as As, Cr, Fe, V, Zn, and Cu.

VERTICAL PROFILING OF ATMOSPHERIC BACKSCATTER WITH A RAMAN-AEROSOL LIDAR Atanaska D. Deleva a, Zahary Y. Peshev a, Alexander S. Slesar

b

, Sergey Denisov b, Lachezar A. Avramov

a

a Institute

of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria, b B.I.Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68 Nezavisimosti Ave., 220072 Minsk, Belarus ABSTRACT Results of experimental monitoring of tropospheric aerosol fields are presented. Investigations are carried out with a combined Raman-aerosol lidar. Advantages of atmospheric particle measurements with the combined lidar technique are discussed. The Raman-aerosol lidar is based on a powerful Q-switched frequency-doubled Nd:YAG laser. A simple and efficient three channel lidar receiving system is developed, based on novel photo-receiving modules with a very compact design and reliable operation. The lidar’s acquisition system is provided with a specialized software, allowing performing of comfortable detection, conversion, and processing of lidar data. The Raman-aerosol lidar is used for conducting regular remote sensing of desert dust and cloud layers and for determination of their backscattering properties. Vertical profiles of range corrected lidar signals are shown and discussed. Colormaps of experimentally obtained results are also presented, illustrating the temporal evolution of atmospheric aerosol fields.

TWO-WAVELENGTH LIDAR OBSERVATIONS OF SOME CASES OF AEROSOL LOADING OVER SOFIA, BULGARIA Atanaska D. Deleva a, Zahary Y. Peshev a, Alexander S. Slesar b, Sergey Denisov b, Lachezar A. Avramov a , and Dimitar V. Stoyanov a a Institute

of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria b B.I.Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68 Nezavisimosti Ave., 220072 Minsk, Belarus ABSTRACT Aerosols have a strong impact on the planet’s thermal balance, air quality, and a variety of atmospheric processes and phenomena. In this work we present some results from a long term lidar observations of tropospheric aerosols over the city of Sofia, Bulgaria within the framework of the European project “EARLINET-ASSOS”. Vertical profiles of range corrected lidar signals are processed and analyzed. The temporal evolution and the spatial distribution of atmospheric aerosol fields are illustrated by 2D-colormaps in height-time coordinates. We investigated several cases of aerosol loading such as: transport of Saharan dust (at altitudes from 3 km to 5 km), highly situated layers (from 9 km to 15 km), and anthropogenic smog (up to 2 km). All measurements were performed by using the two aerosol spectral channels of a combined Ramanaerosol lidar developed in the Laser Radar Lab, Institute of Electronics, Bulgarian Academy of Sciences. It is based on a Qswitched powerful frequency-doubled Nd:YAG laser (output pulse power: up to 1 J at 1064 nm; up to 100 mJ at 532 nm; pulse duration 15 ns FWHM; repetition rate 2 Hz). A Cassegrain telescope (35 cm diameter, 200 cm focal length) collects the backscattered radiation. The lidar receiving system is based on novel high sensitive photo-receiving modules. The acquisition system provides signal registration with spatial resolution of 15 m (100 MHz 14-bit ADC). It allows performing of detection, storage, and processing of large volume lidar data. Our observations are in good agreement with the forecasts 112

of Barcelona Supercomputing Center, concerning Saharan dust transport. Results obtained display the lidar’s ability for reliable sensitive detection of desert dust and high level aerosol layers in both the troposphere and tropopause.

LIDAR STUDY OF AEROSOL LAYERS OVER SOFIA IN THE FRAME OF EARLINET-ASOS PROJECT Ivan Grigorov, Georgi Kolarov and Dimitar Stoyanov Institute of Electronics, Bulgarian Academy of Sciences 72 Tzarigradsko Shose Blvd., 1784-Sofia, Bulgaria ABSTRACT In this work we present some results of lidar remote sensing of aerosol layers in the atmosphere in Sofia region. They are based on the observations by lidar system equipped with a CuBr-vapor laser with high pulse repetition of 13 kHz and receiver in photon counting mode. The measurements are made in frame of the project European Aerosol Research Lidar Network - Advanced Sustainable Observation System (EARLINET - ASOS). For some of presented results a conclusion about atmospheric aerosol’s origins was made upon analyses of the information about the weather condition during the lidar measurements. Such information was obtained by the weather-forecast maps provided by the Atmospheric Modeling and Weather Forecasting Group of NTUA and the Forecast system of Barcelona Supercomputing Centre and accessible via Internet. Additional information is provided by calculations of the backward air mass trajectories, using online software of NOAA about HYSPLIT model (HYbrid Single-Particle Lagrangian Integrated Trajectory). A common database that automatically collects the data products provided by the individual lidar stations is build and makes data of measurements available to the scientific community.

LIDAR MEASUREMENTS OF ATMOSPHERIC DYNAMICS OVER HIGH MOUNTAINOUS TERRAIN Zahary Y. Peshev , Atanaska D. Deleva , Tanja N. Dreischuh, and Dimitar V. Stoyanov Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria ABSTRACT Conditions in the low atmosphere can be strongly influenced by mountain‘s relief, which causes formation of turbulent zones and air flows resulting in specific behavior of atmospheric parameters. In some cases, mountainous terrain provokes appearance of orographic waves. Therefore, detailed investigations of the atmospheric dynamics at different time scales near mountain’s surface are important for better understanding atmospheric behavior in such regions. In this work, results of lidar measurements on the dynamics of atmospheric layers over the ridge and North-East slope of Vitosha Mountain, close to Sofia, Bulgaria, are reported. Measurements are carried out at 1064 nm wavelength by using one of the aerosol channels of a combined Raman-aerosol lidar based on a powerful frequency-doubled Nd:YAG laser (output pulse energy: up to 1J at 1064 nm, pulse duration: 15 ns FWHM; repetition rate: 2 Hz). The acquisition system provides signal registration with a lidar range resolution of 15 m (100MHz 14-bit ADC). The data collecting time period is February – May, 2009, covering a variety of weather conditions. The investigated mountainous area, situated from 6 km to 10 km away from the lidar station, is scanned reiteratively within 7o-12o slope-angle range. In order to follow the short-term air dynamics, multiple series of 4-pulse-averaged lidar profiles are registered. Range corrected lidar signals (RCLS) are stored and further processed statistically. The resulting normalized standard deviation calculated over 1000 laser shots is used as a characteristic of the atmospheric dynamics. Range profiles of the RCLS standard deviation are built, corresponding to heights of up to 2 km. Colormap plots are presented, illustrating the temporal evolution of the atmospheric aerosol distribution over the mountainous area. Intense dynamics of atmospheric inhomogeneities above the mountain is revealed, exceeding considerably the one over the plane zone. Indications for presence of terrain-following air flows are also analyzed and discussed.

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CONTRIBUTION TO THE STUDY OF RAINFALL REGIME IN THRACE A.S. Vlassi

(1)

and T. A. Mavroudakis

(2)

National & Kapodistrian University of Athens, Dept. of Geology and Geoenvironment, Laboratory of Climatology, Ph.D. Candidate 2)National & Kapodistrian University of Athens, Dept. of Philosophy and History of Science, Lecturer ABSTRACT 1)

A time-consuming validation of rainfall records in Thrace, an area of great ecological interest area in North-eastern Greece, for a period of 30 years in the second half of the 20th century enable new climatological studies for the region, the first results of which are here presented. In this paper the daily, monthly and annual rainfall data collected in eight representative stations for a period of 30 years in the second half of the 20th century are analysed in detail. Multidimensional statistical analysis is used in order to detect the specific characteristics as well as any possible changes and trends in the rainfall regime of the area leading to a better insight. Moreover emphasis is put on the non-rainy days intervals in an attempt to further examine potential changes in the dry periods. The Standardised Precipitation Index (SPI) is also used in order to assess the climate of the region and identify the drought events in a temporal basis. Finally, findings are compared to results of similar studies for nearby regions so as similarities and differences to be hence pronounced.

EFFECTS OF SALINITY ON THE LEAF SPECTRAL REFLECTANCE AND BIOCHEMICAL PARAMETERS OF NITROGEN FIXED SOYBEAN PLANTS (Glycine max L.) D. Krezhova 1, E. Kirova 2, T. Yanev 1, I. Iliev 1 1

Solar-Terrestrial Influences Institute, Bulgarian Academy of Sciences 2 Institute of Plant Physiology, Bulgarian Academy of Sciences

ABSTRACT High salinity in soil or irrigation water is a common environmental problem influencing plant growth and productivity by provoking osmotic stress and ion toxicity together with induction of oxidative stress. Salinity affects almost every aspect of the physiology and biochemistry of plants and significantly reduces yield. High exogenous salt concentrations affect seed germination, water deficit, cause ion imbalance of the cellular ions. The soil nitrogen content is one of the most important factors that limit plant growth. In sustained agronomic systems, both the biological nitrogen fixation and an adequate management of the organic matter, play important roles. On the other hand, symbiotic nitrogen fixation by rhizobia replaces expensive nitrogen fertilizers. Biotic and abiotic factors affect indigenous and introduced rhizobia populations. Abiotic factors such as low water availability in soil, salinity, extreme pHs and agrochemicals may limit the symbiotic process affecting survival and proliferation of the microorganism in soil and rhizosphere. Remote sensing techniques have been used to monitor crops throughout their growing period to help in making decisions for good agricultural practices. Hyperspectral reflectance data have been widely used to assess changes in various biophysical and ecological properties of plants, crops, and ecosystems in response to the changes in the environment. In this study in order to evaluate the effects of the salinity on the nitrogen fixed soybean plants (Glycine max L., cultivar Pavlikeni) a comparative analysis was performed between the changes of the leaf spectral reflectance data and the stress markers such as phenols, malondialdehid, thiol groups, proline and hydrogen peroxide and pigments (chlorophyll a and b), estimated by biochemical methods. The soybean plants were grown under controlled conditions as water cultures on Helrigel nutrient solution. Three day’s seedlings were inoculated with suspension of Bradyrhizobium japonicum strain 273. Salinity was performed at the stage of 2nd - 4th trifoliate expanded leaves by adding of NaCl in the nutrient solution in concentrations 40 mM and 80 mM. Measurements of fresh detached leaves were performed on the 14th day after the treatment. The leaf spectral reflectance was obtained by optical measurements with a USB2000 fibre optic spectrometer in the visible and near infrared spectral ranges (450-850 nm). The data were subjected to statistical analysis involving Student’s t criterion and discriminant analysis. The leaf reflectance of the control and treated plants at eight wavelengths in the red, green, red-edge and the near infrared ranges of the spectrum were used in the analysis. Statistically significant differences were found through the Student’s t-criterion between the spectral reflectance of the 114

leaves of control and treated plants at the two NaCl concentrations in all of the ranges examined with the exception of the near infrared range at 40 mM NaCl concentration. Similar results were obtained through discriminant analysis in one dimensional spaces utilizing data in the same eight wavelengths in the investigated spectral ranges. Some of the investigated biochemical parameters (phenols and MDA) and the content of chlorophyll a and b were found to decrease with both NaCl concentrations. Their values were changed approximately twofold at 80 mM NaCl salinity. In the spectral reflectance characteristics this effect is manifested by decreasing of the values in the green and red ranges. Proline, hydrogen peroxide and thiol groups turned out to be most informative stress markers whose values increased with the increase of the NaCl concentrations. At 80 mM NaCl the values of the three markers showed about twofold increase giving evidence that the soybean plants were stressed in comparison with the control. This finding is in agreement with the results from the spectral reflectance analysis.

EFFECTS OF SALINITY ON THE CHLOROPHYLL FLUORESCENCE OF NITROGEN FIXED SOYBEAN PLANTS (Glycine max L.) I. Iliev 1 , D. Krezhova 1 , T. Yanev 1 , E. Kirova 2 1

Solar-Terrestrial Influences Institute, Bulgarian Academy of Sciences 2 Institute of Plant Physiology, Bulgarian Academy of Science

ABSTRACT Salinity and drought are two major environmental factors determining plant productivity and plant distribution. Understanding plant responses and plant tolerance to salinity and water deficit is therefore of fundamental importance and forms one of the major research topics. Plants can perceive abiotic stresses and bring forth appropriate responses with altered metabolism, growth and development. Biological nitrogen fixation is dramatically affected by environmental constraints such as water and salinity stresses. These stresses induce the over-production of reactive oxygen species and, in turn, oxidative stress that may be responsible for the biological nitrogen fixation decline at the molecular level. Oxidative stress, occurring under different environmental stresses, has been strongly related to physiological damage. However, a direct relationship between oxidative stress and the decline of biological nitrogen fixation, independently from any other cellular damage resulting from adverse environmental situations, has yet to be demonstrated. Chlorophyll fluorescence is a sensitive indicator of photosynthetic energy conversion that occurs during the light reaction and it is very useful to study the effects of photosynthesis. Chlorophyll fluorescence can be modified by any factor affecting the light reaction pathway of photosynthesis, including many environmental stresses. Various stress conditions may reduce the rate of photosynthesis, and disturb the light-driven photosynthetic electron transport via heat emission and chlorophyll fluorescence. The objective of this study was to evaluate the effects of NaCl salinity on chlorophyll fluorescence of nitrogen fixed soybean plants (Glycine max L., cultivar Pavlikeni). The results were compared with the effects of NaCl salinity on the leaf spectral reflectance on the same soybean plants. The plants were grown under controlled conditions as water cultures on nutrient solution of Helrigel. Three day’s seedlings were inoculated with suspension of Bradyrhizobium japonicum strain 273. Salinity was performed at the stage of 2th - 4th trifoliate expanded leaves by adding of NaCl in the nutrient solution in concentrations 40 mM and 80 mM. The chlorophyll fluorescence was registered by an Ocean Optics USB2000 spectrometer in the spectral range 600-850 nm. As a source of actinic light a light emitting diode with the maximum of the light output at 470 nm was used. The fluorescence spectra were registered in time acquisition mode every 2 seconds. At least 40 spectra from each soybean leaf were obtained, the leaves being taken from 20 control and 20 plants treated with the two NaCl concentrations. The spectral reflectance data were collected in the visible and near infrared spectral ranges (450-850 nm) by the same spectrometer operating in reflectance mode. All measurements were performed on the 14th day after the treatment. The course of the fluorescence spectra and the slow transient fluorescence kinetics were investigated. The Student tcriterion, and discriminant analysis were applied to estimate the changes between leaf fluorescence spectra of control and treated soybean plants in five characteristic wavelengths in the spectral range 600-850 nm (in the middle of the leading edge, first maximum, between first and second maximum, second maximum and the middle of the trailing edge). Statistically significant differences were established by the t-criterion at p2B, C+A->2C, to emulate a computer network with e-mail viruses. Different topologies of the network are considered. When the parameters of the network are varied, it is observed that very high clustering coefficients are necessary for a pandemics to happen. The differences between the networks of computer users, e-mail networks, and social networks, as well as their role in determining the nature of epidemics are also discussed.

THE NEURAL NETWORK APPROACHING FOR NON-LINEAR HEAT TRANSFER PROCESSES Gabriel Murariu, M. Praisler, L. Georgescu, M. Voiculescu, Faculty of Sciences, University Dunarea de Jos, Galati, Romania ABSTRACT The mass and heat transfer processes are, in the last period, important subjects in the cooling and freezing industrial procedures domain. A study of the past years literature reveals an increasing interest for controlling and freezing front propagation in cooling processes. The main reason for this revise is due to the imperative energy preservation request. Using a set of experimental data sets from macrobiotic cooling and freezing process, it was researched a model to succeed in evaluating the temperature dynamics, the heat transfer magnitude and, in some hypothesis, the freezing front propagation. In the first stage were considered identification system methods in order to find out the fitting mathematical model. For restricted temperature domains, could be used these first order models with satisfactory approximation. Basing on them, in the second level, is considered a merged representation which could describe the temperature evolution for these systems. On the third stage, after short presentations of our derived models using specific neural networks, was developed a comparison in order to succeed in temperature evolution assessment. In the last segment is presented the heat transfer coefficients’ evaluation and the temperature evolution. Reference [1]. V. Dorodnitsyn, R. Koslov, A heat transfer with a source: the complete set of invariant difference Scheme, (2006), [1]. D. BATALU, H. GUOQIU, A. ALOMAN, L. XIAOSHAN, Z. ZHIHUA, J.O.A.M. Vol. 8, No. 2, 2006, p. 694 - 698 [2] E. G. CRAVALHO, C. L. TIEN, R. P. CAREN, J. Heat, Transfer 89, 351 (1967). [3] S. WIGGINS, “Introduction to applied nonlinear dynamical systems and chaos”, Springer N. Y.,1990. [4]. A.GARRIGA and F.RITORT, Zeitschrift für Physik B Condensed Matter, Vol. 21, No 1, 115-120, (1975) [5]. G. BIMONTE, Phys. Rev. Lett 96, 160401 (2006) [6] V. DORODNITSYN, R. KOZLOV, Journal of Nonlinear Mathematical Physics Volume 10, N0. 1 (2003), [7] G. MURARIU, D. TOMA, arXiv:physics/0505053v1 [8]. C. P. CRISTESCU, B. MEREU, M. DIESTELHORST, Phys. Rev. E 66, 016602 (2002). [9] M. IZHIKEVICH, F. C. HOPPENSTEADT, SIAM J. Appl. Math. 63, 1935 (2003) [10]. GABRIEL MURARIU, MIHAELA CHIRILA, MIMI DOBREA, “Software approaching for heat transfer coefficients’ evaluation”, Revue de Physics, in press [11]. D.V. CHUROCHKIN, S. SAHLING, V.A. OSIPOV, Phys. Rev. B 72, 014116 (2005) [13] D. TOMA G. MURARIU, Heat and Molecular Physics, Ed. Fundatiei Universitare, (2003)

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NONLINEAR FLOOD ASSESSMENT WITH NEURAL NETWORK APPROACHING Gabriel Murariu

1,

Gh. Puscasu

2

1

Physics Department, Faculty of Sciences, University “Dunarea de Jos”, 47 Domneasca Street, 800008, Galati, Romania 2 Faculty of Computer Science, “Dun årea de Jos” University of Gala †i ABSTRACT In our days, theoretical investigations are used in a huge variety of research fields. An important aim in most such works is to obtain the mathematical model for the considered system or process. The common approach is therefore to start from measurements of the behavior of the system and the external influences (inputs) and try to determine a mathematical relation between them without going into the details of what is actually happening inside the system. Accepting this, there could be investigated the climatic phenomenon in a very sensitive area of the Lower Danube zone where, in the past years, a series of climatic problems have been happening. In these conditions, the climatic risk factors’ management is a necessity. In a regular way, there could be considered and designed a nonlinear model for the climatic factors’ analysis by using a huge historical evidence data archive. In a series of previous paper, was considered different procedures for mathematical model building by employing Data-Based Mechanistic (DBM) modeling [1], neural networks [2-3], Kalman filter design [4] or nonlinear time series analysis [5, 6], in order to succeed in reaching a good correlation between the gauging points’ recorded data. In this paper is exposed a comparative study between a numerical advance basing on Navier-Stokes equations and a neural network approach, based on internal recurrent neural networks (IRNN). The use of neural networks for water flood systems was not a novelty [3]. A series of recent works in this area reveals a consistent achievement and a great success for such all approaching method [7]. However, the congregate computational complexity of neural identification can be greatly reduced if the whole system is decomposed into subsystems. Such all approach is presented considering the internal state estimation when no measurements coming from the sensors are available for system states. A modified backpropagation algorithm is introduced in order to train the IRNN for nonlinear system identification. In order to succeed in applying this idea, a particular case study is provided to show the performance of the proposed design approaching by comparing with a common computational fluid dynamics numerical evaluation. It is applied to the specific case of the Siret River which presented a series of water flood episodes in the last years. This result is the first step toward a DSS - Decision Support System in the area. The relationship between the simulated results and the registered data allows considering our particular method to be useful for considered water flood assessment. Reference [1]. K. Gabrovska, Software modeling of stochastic climatic processes, International Conference on Computer Systems and Technologies - CompSysTech’07 [2]. Gh. Puscasu, V.Palade, Al. Stancu, _. a. “Classical and Smart process leading systems”, Bucuresti, MATRIX ROM, (2000) [3] [4] R. J. Romanowicz, P. C. Young, K. J. Beven, F. Pappenberger, Advances in Water Resources 31, 1048–1056, (2008) [5] G. Gioia, F. A. Bombardelli, Phys. Rev. Letters, 88, 1, 1-4, (2002) [6]. F. Lafont, J.-F. Balmat , Fuzzy logic to the identification and the command of the multidimensional systems,(INVITED PAPER) International Journal of Computational Cognition Volume 2, Number 3, Pages 21–47, September 2004 [7] R. Goncalves, A. A. Pinto, arhiv:0807.2988 (2008) [8] G. Murariu, M. Praisler, “Numerical analysis of the rain falls assessment”, The fourth Antional Conference of ap [9] V.P Singh, Elementary Hydrology, Prentice-Hall Publishing Company, Inglewood, New Jersey, pp.614. (1992) [10]. Jennifer Meyer, COMPARATIVE ANALYSIS BETWEEN DIFFERENT FLOOD ASSESSMENT TECHNOLOGIES IN HAZUS-MH, pp.11. (2002) [11] P. J. Mizgalewicz, Water Balance of the 1993 Midwest Flood, pp.4-6, (2003)

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“RECORDING AND CALCULATING GUNSHOT SOUND” Change of the Volume in Reference to the Distance TSIATIS E. NIKOLAOS Undergraduate student in the Physics Department of the University of Athens, Ballistics Expert Captain of Hellenic Police, Criminal Investigations Division, Forensic Science Labs, Firearms and Tool marks Laboratory, Athens, GREECE KEYWORDS: gunshot sound, firearm, measurement, decibel, distance, volume ABSTRACT An experiment was conducted in an open practice ground (shooting range) regarding the recording of the sound of gunshots. Shots were fired using various types of firearms (seven pistols, five revolvers, two submachine guns, one rifle, and one shotgun) in different calibers, from several various distances with reference to the recording sources. Both, a conventional sound level meter (device) and a measurement microphone were used, having been placed in a fixed point behind the shooting line. The sound of each shot was recorded (from the device). At the same time the signal received by the microphone was transferred to a connected computer through an appropriate audio interface with a pre-amplifier. Each sound wave was stored and depicted as a wave function. After the physic-mathematical analysis of these depictions, the volume was calculated in the accepted engineering units (Decibels or dB) of Sound Pressure Level (SPL). The distances from the recording sources were 9.60 meters, 14.40 m, 19.20 m, and 38.40 m. For the experiment the following devices/instruments were used: a) Sound level meter (SLM), model “CEL-440”, with the “CEL-250” microphone, b) Measurement microphone, model “ECM800”/BERINGER, c) Audio interface, with pre-amplifier “MOTU Ultralite”, d) Lap top, e) the soft wares: “Audacity - win - 1.2.6” & “Pratt5032-winsit”, f) Digital Altimeter, model “CNS-DC2 Explorer” / CANYON (for the environmental conditions), g) Range finder, model “LEICA GEOVID 7 X 42 BDA”. The experiment was carried out by using the following calibers: .22LR, 6.35 mm (.25 AUTO), 7.62 mm Tokarev (7,62X25), 7.65 mm (.32 AUTO), 9 mm Parabellum (9X19), 9 mm Short (9X17), 9 mm Makarov (9X18), .45 AUTO, .32 S&W, .38 S&W, .38 SPECIAL, .357 Magnum, 7,62 mm Kalashnikov (7,62X39) and 12 GA. Tables are given for the environmental conditions (temperature, humidity, altitude & barometric pressure), the length of the barrel of each gun, technical characteristics of the used ammunition, as well as for the volume taken from the SLM. The data for the sound intensity were collected after 168 gunshots (158 single shot & 10 bursts). According to the results, a decreasing of the volume, equivalent to the increasing of the distance, was remarked, as it was expected. Values seem to follow the Inverse square Law. For every doubling of the distance from the sound source, the sound intensity diminishes by 5.9904±0.2325 decibels (on average). In addition, we have the chance of determining the volume of the gunshot sound coming from a certain type of weapon. A further application could be the calculation of the distance from a shooting firearm if one is aware of a recorded volume. References 1. R. F. Powell & M. R. Forrest., “Noise in the Military Environment”, Brassey`s Defence Publishers, U.K., 1988. 2. Philip H. Dater, MD, “Sound Measurements – Firearm Sound Level Measurements: Techniques and Equipment”, ATI Star Press-Antares Technologies, Inc., Boise, Idaho, U.S.A., 2000. 3. Lucien C. Haag, Forensic Science Services, “The Sound of Bullets”, AFTE Journal – Volume 34 – Page 255, Sum. 2002. 4. Philip H. Dater, MD, “Firearm Sound Levels and Hearing Damage”, Antares Technologies, Inc., Boise, ID, U.S.A., 2002, 04.

METHODOLOGY OF ASSESSMENT OF SYSTEM LEVEL SUSCEPTIBILITY AND PROTECTION GUIDELINES FOR SYSTEMS AND DISTRIBUTED INFRASTRUCTURE, FROM HEMP AND HPEM Tsatalas Stylianos, BSc Physics/MSc Electronics, INTRACOM Telecom Damoulos Dimitrios, BSc Physics/MSc Electronics, 7th Vocational School of Athens ABSTRACT HEMP (High Energy Electromagnetic Pulse) occurs as a result of a high-altitude nuclear explosion and can cover several millions of square kilometres with electric field strengths of up to tens of kV/m. HPEM (High Power Electromagnetic) is the collective name given to a set of high power radio frequency (RF) sources that are capable of generating high levels of RF at ranges 0.q>0, and the variable x: 0 ≤ x ≤ 1. Analogous procedure is used at the approximation of histograms for the time intervals between the couples of earthquakes. The analytical mode of the used curve is:

. The success of all attempts for studying the fortuity of a series of main events depends on the ability the aftershocks to be identified and their removal from the catalogue. The development of the studies of the spatial distribution of the earthquakes under the so-called “methods of the moments” – from second or higher order seem to be suitable for distinction of the aftershock series, too, as Reasenberg does for example. For determining the statistic independence between the studied couples of events the preliminary filtration of aftershock events is applied where the Reasenberg’s spatial-time window, realized in the program Zmap is used. On the catalogues of the studied seismic zones additional filtration is made, in order series of relatively big events in each zone to be distinguished. Lower magnitude threshold Mmin = 4.0 is chosen, and some zones have also a second series with Mmin = 5.0. The proposed methodology for study of the distributions of distances and time intervals between consecutive big earthquakes from different seismogenic zones shows that there are mathematical functions suitable for such descriptions. The received results confirm that the used approximating functions show differences in the spatial distribution of the events from the different seismogenic zones. The methodology allows a qualitative evaluation of the quality of the received parameters to be given. There is a real perspective, received as a result of the carried-out studies, the proposed methodology to be applied for formal recognition of earthquakes from different seismogenic zones, as well as for qualitative evaluation of the reliability of this recognition.

VERIFYING THE DEPENDENCE OF FRACTAL COEFFICIENTS ON DIFFERENT SPATIAL DISTRIBUTIONS Dragomir Gospodinov* ,**, Elisaveta Marekova*, Alexader Marinov* * Plovdiv University “Paisii Hilendarski”, Bulgaria ** Geophysical Institute of Bulgarian Academy of Sciences ABSTRACT A fractal distribution requires that the number of objects larger than a specific size r has a power-law dependence on the size N(r)=C/r1) µ r -1) where D is the fractal dimension. Usually the correlation integral is calculated to estimate the correlation fractal dimension of epicentres. A ‘box-counting’ procedure could also be applied giving the ‘capacity’ fractal dimension. The fractal dimension can be an integer and then it is equivalent to a Euclidean dimension (it is zero of a point, one of a segment, of a square is two and of a cube is three). In general the fractal dimension is not an integer but a fractional dimension and there comes the origin of the term ‘fractal’. The use of a power-law to statistically describe a set of events or phenomena reveals the lack of a characteristic length scale, that is fractal objects are scale invariant. Scaling invariance and chaotic behavior constitute the base of a lot of natural hazards phenomena. Many studies of earthquakes reveal that their occurrence exhibits scale-invariant properties, so the fractal dimension can characterize them. It has first been confirmed that both aftershock rate decay in time and earthquake size distribution follow a power law. 134

Recently many other earthquake distributions have been found to be scale-invariant. The spatial distribution of both regional seismicity and aftershocks show some fractal features. Earthquake spatial distributions are considered fractal, but indirectly. There are two possible models, which result in fractal earthquake distributions. The first model considers that a fractal distribution of faults leads to a fractal distribution of earthquakes, because each earthquake is characteristic of the fault on which it occurs. The second assumes that each fault has a fractal distribution of earthquakes. Observations strongly favour the first hypothesis. The fractal coefficients analysis provides some important advantages in examining earthquake spatial distribution, which are: - simple way to quantify scale-invariant distributions of complex objects or phenomena by a small number of parameters. - it is becoming evident that the applicability of fractal distributions to geological problems could have a more fundamental basis. Chaotic behaviour could underlay the geotectonic processes and the applicable statistics could often be fractal. The application of fractal distribution analysis has, however, some specific aspects. It is usually difficult to present an adequate interpretation of the obtained values of fractal coefficients for earthquake epicenter or hypocenter distributions. That is why in this paper we aimed at other goals – to verify how a fractal coefficient depends on different spatial distributions. We simulated earthquake spatial data by generating randomly points first in a 3D space - cube, then in a parallelepiped, diminishing one of its sides. We then continued this procedure in a 2D and 1D space. For each simulated data set we calculated the points’ fractal coefficient (both correlation fractal dimension and ‘capacity’ fractal dimension of epicentres) and then checked for correlation between the coefficients values and the type of spatial distribution. In that way one can obtain a set of standard fractal coefficients’ values for varying spatial distributions. These then can be used when real earthquake data is analyzed by comparing the real data coefficients values to the standard fractal coefficients. Such an approach can help in interpreting the fractal analysis results through different types of spatial distributions.

SEISMICITY, STRESS AND STRAIN IN THE CENTRAL PART OF BALKAN REGION AS A RESULT OF EARTHQUAKE AND GPS MONITORING Emil Botev 1 , Dimitar Dimitrov 2 , Ivan Georgiev

2

1Geophysical 2 Central

Institute, Bulgarian Academy of Sciences, 1113 Sofia, Acad. G. Bonchev Str., Bl. 3. Laboratory of Geodesy, Bulgarian Academy of Sciences, 1113 Sofia, Acad. G. Bonchev Str., Bl. 1

ABSTRACT In this report an attempt to elucidate the geodynamic situation in Bulgarian territory and the very adjacent lands from seismological, geological and geodetic view points is proposed. For this purpose a short analysis of the historical and nowadays seismicity is made. The fault plate solutions of about two hundred earthquakes and corresponding stresses are also analysed. For the purposes of the quantitative stress and strain modelling some seismic zoning is discussed and the main seismological and focal mechanisms characteristics for each zone are presented. The mean stress tensors for the most zones are calculated by means of an inversion of the focal mechanisms data using the technique of Gephart. The released strain is computed from the moment tensors of the focal mechanisms according to the relation of Kostrov. In general, the obtain mean strain tensors of deformation show some agreement with the calculated mean stresses. Several local misfits and the whole geodynamic situation are analysed under the lights of some present tectonic hypothesis. On the base of the analysis of the nowadays seismicity, stress and strain in the territory of Bulgaria some speculations about the ongoing geodynamic processes in the central Balkans are drawn. In Bulgaria and the very adjacent lands, the focal mechanisms and stress tensor inversion show that the present acting state of stress is strictly connected to the complex geodynamics of the Central Balkan area. The prevailing normal extensional stresses obtained from the seismological data could be explained by the above discussed two main regional processes. The first one is the post-collisional extensional collapse of the Central Balkan orogens under influence of the paleosubduction in the Vardar paleobasin and the present days pushing of the Adriatic plate towards ENE. The second process is the complex influence of the existing SW horizontal movements along the North Anatolian fault while passing through the Aegean Sea; it causes extension of the eastern parts of Srednogorie zone and formation of an extensional province to the North from the North Aegean Trough The GPS-measurements of the present state of crustal deformation in the Eastern Mediterranean indicate that the biggest movements (around 30-40 mm/y) are observed towards SSW in the central and southern parts of the Aegean plate. At the same time, a few measurements in northern Greece reveal much more smaller movements in the south direction (around 5-6 mm/y). 135

The observed great difference determines existence of an extensional province in Northern Greece. According to some authors, the SW zone of Bulgaria is characterised by NE movements with velocity around 3-4 mm/y. According to the same authors some places in Northern Bulgaria are characterised by NNE oriented movements with almost the same velocity. These different orientations of the present crustal movements in northern Greece, western and northern Bulgaria can explain the predominance of extensional subhorizontal stresses in the central Balkans. In the same picture, the Middle Mesta Fault Lineament (MMFL) is the margin between the north Aegean and the central Balkan region. The extensional regime in the north Aegean area and the influence of the Anatolian plate have caused one additional opening of the southeastern part of the Srednogorie structural province. The NNE-ward recent crustal movements (scarcely documented) in north Bulgaria can be associated to the general NE-ward pushing of the Adriatic plate and the westward movements of the Anatolian plate and Bulgarian north Black sea area.

STUDY OF MUNELLA ORES (Puka Region, Albania) Engjell Liçaj, Jorgo Mandili, Boran Tabaku, Niko Thomo Institutes: University “Ismail Qemali”, Vlora ABSTRACT The study of Munella ores is based on four analyses (A, B, C and cores). They represent different types of minerals in the Munella area. The geologist of Puka Geological Enterprise took cores. A Core: It represents an ore with pyrite and chalcopyrite where copper and sulfur contents are 0.77 and 8.2 % respectively. B Core: This core represents an ore with spharelites and pyrite where zinc content is 1.5 % and 2.9 % sulfur one. C Core: It is a chalcopyrite ore, massive in nature, where copper content is 2.01 % and 36 % sulfur one. D Core: It also represents copper- zinc - sulfur ore where their content is 0.66, 1.00 and 4.28 % respectively. Each core is studied individually by selective schema to have copper, zinc and pyrite concentrates. Copper and pyrite concentrates will be the first material for pyro- metallurgical industry.

SYNTHESIS AND THERMOELECTRIC PROPERTIES OF BI Ch. Iona (1), E. Hatzikraniotis

(2),

K.M. Paraskevopoulos

(2)

2SE 3-XS 3

and Th. Kyratsi

SERIES

(1,*)

(1)Department

of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, Cyprus (2)Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece In the last decades there has been a great interest on the field of thermoelectrics. The main thermoelectric applications concern cooling modules and power generation. Some of the more significant features of thermoelectric modules include the ability to heat and cool with the same module, the ability to generate electrical power from “waste” energy, precise temperature control, spot cooling, friendliness and sensitivity to the environment, small size and weight and having no moving parts. Good thermoelectric materials have high Seebeck coefficient, high electric conductivity and low thermal conductivity. These three parameters are incorporated in the “figure-of-merit”, Z, which is given by ZT=S2TÛ/Î where S is the Seebeck coefficient, Û is the electrical conductivity and Î is the thermal conductivity at certain temperature. Thermoelectric materials are investigated aiming to maximize power factor (S2Û) and minimize the thermal conductivity in order to increase the thermoelectric figure of merit ZT. The best thermoelectric materials are found to be heavily doped semiconductors since insulators have poor electrical conductivity and metals have poor Seebeck coefficient. B2Q3 (M: Bi, Sb and Q: Te, Se) compounds have been extensively studied since they have very good thermoelectric properties that exceed ZT of 1 at room temperature and find application on the commercial modules. Bi2Se3-xSx compounds appear that have not attracted much attention even though the few studies on such system show interesting physical properties. In this work, Bi2Se3-xSx solid solutions, with low x values, are synthesized from melt. The solid solutions with different x values were studied in terms of purity using powder X-ray diffraction (PXRD) while the lattice parameters were calculated based on the PXRD showing the reduced unit cell as the x value was increased. The SEM images used to study the morphology of the Bi2Se3-xSx members. The thermoelectric properties (Seebeck coefficient and electrical conductivity) were studied showing increase on the doping level of the initial material. The carrier concentration is estimated by IR reflectivity analysis based on Drude model.

136

RESTRICTIONS ON MEASUREMENT OF ROUGHNESS OF TEXTILE FABRICS BY LASER TRIANGULATION: A PHENOMENOLOGICAL APPROACH Pellumb Berberi*, Burhan Tabaku* Deartment of Engineering Physics Faculty of Mathematic and Physics Engineering, Polytechnic University of Tirana, Albania ABSTRACT Laser triangulation method is one of the methods used for contactless measurement of roughness of textile fabrics. Method is based on measurement of distance between the sensor and the object by imaging the scattered light from the surface. However, experimental results, especially for high values of roughness, show a strong dependence on duration of exposure time to laser pulses. Use of very short exposure times and long exposures times cause appearance on the surface of the scanned textile of pixels with fictive peak heights. The number of fictive peaks increases with decrease of exposure time down to 0.1 ms, and increases with increase of exposure time up to 100 ms. Appearance of fictive peaks leads to nonrealistic increase of roughness of the surface both for short exposure times and long exposure times reaching a minimum somewhere in the region of medium exposure times, 1 to 2 ms. The above effect suggests a careful analysis of experimental data and, also, becomes an important restriction to the method. In this paper we attempt to make a phenomenological approach to the mechanisms leading to these effects. We suppose that effect is related both to scattering properties of scanned surface and to physical parameters of CCD sensors. The first factor becomes more important in the region of long exposure times, while second factor becomes more important in the region of short exposure times.

CHARACTERIZATION OF A XENON GAS JET INTO VACUUM BY MEANS OF INTERFEROMETRIC TECHNIQUE ILIR VULLKAJ Polytechnic University, Tirana, Albania Arqile Done University “Eqrem ABSTRACT

Çabej”, Gjirokastra, Albania

The experimental density distribution of a xenon-gas jet into vacuum through a nozzle, has been studied by means of an interferometric method using an interferometer of Michelson. Such results are shown in this contribution. The xenon-gas jet is produced from a supersonic nozzle. It has been studied for its usability as a EUV lithography light source. The conversion efficiency of EUV (Extreme Ultra Violet) plasma radiation sources (induced by laser) depends on cluster density arising from the gas jet efflux. Its characterization is very important. The intention to find varied sources of EUV radiations from the interaction laser-gascluster, has pushed us to study the throw of the xenon gas in empty, and the formation of the clusters. The purpose of the present research is that to optimize the characteristics of the gaseous target and then to individualize the fittest zone, where the above mentioned interaction will be realized. In our work the gas-injection nozzle is a convergent-divergent type with conic profile. We can find the gas-injection zone with higher density, (on which the laser spot will be focused) using a interferometric method. Though gas efflux inside the vacuum chamber is characterized by a high Mach number, the duration of the laser primary pulses, which generate plasma, is really shorter by orders of magnitude, so to assure efficient interactions with high-density quasi-stable gaseous volumes. The comparison of the experimental data from our interferometric method with a fluid-dynamics numerical method (using a appropriate software) seems to be good. The results of the two methods for the study of the gas density, are convergent.

DEVELOPMENT OF PROTON EXCHANGE TECHNOLOGY IN THE ISSP – OPTICAL WAVEGUIDES IN ELECTRO-OPTICAL CRYSTALS PROTON-EXCHANGED OPTICAL WAVEGUIDES Mariana Kuneva Institute of Solid State Physics – Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd, Sofia 1784, Bulgaria ABSTRACT The contribution of the team working in the field of integrated optics in the Institute of Solid State Physics to the development of proton exchange technology is discussed. Some modifications of its parameters (new protonating sources) 137

and steps (two-step exchange separated by annealing, for example) are pointed out in respect of their effect on the waveguiding properties of proton-exchanged layers. The spectroscopic methods used for phase content characterization of waveguides obtained are also described. These include infrared absorption and reflection spectrometry, X-ray photoelectron spectroscopy, mode spectroscopy and micro & waveguiding Raman spectroscopy.

DEVELOPMENT IN ISSP OF INTEGRATED-OPTICAL ELEMENTS AND DEVICES IN LiNbO 3 INTEGRATED OPTICS IN ISSP Mariana Kuneva and Svetlen Tonchev Institute of Solid State Physics - Bulgarian Academy of Sciences 72 Tzarigradsko Chaussee Blvd, Sofia 1784, Bulgaria ABSTRACT The article presented is a review of the main results on integrated-optical elements and devices developed in the Institute of Solid State Physics. Optical waveguiding structures were obtained by titanium in-diffusion and proton exchange using standard photolithography methods for device patterning. electro-optical-prism, electro-optical-Bragg-modulator, electrically induced strip waveguides, integrated-optical Y-switches, total-internal-reflection-modulator, Mach-Zehnder modulators of classic and new constructions etc. are discussed concerning their parameters and describing their fabrication as well. The emphasis is put on the novelties, advantages and disadvantages of each of them and on the specific problems of their fabrication.

DIFFRACTION OF ACOUSTIC WAVE THROUGH A SLIT WITH A FINITE THICKNESS Burova M., Burov J. and Andreeva A. Sofia University, Faculty of Physics, Department of Physics of Semiconductors, 5 James Bourchier Blvd., Sofia BG-1164, Bulgaria ABSTRACT The acoustic field, transmitted through parallelepiped from fused silica (immersed in water) is registered, which parallelepiped acts the part of slit with a finite thickness. It is shown, that the finite thickness leads to a change of the acoustic wavelength and the distance up to a registration plane. The distance increases, if the acoustic velocity in the material is higher than that in water, independently of actual distance between the slit and data plane. It is shown, if the slit with finite thickness is placed, the Fresnel zone may be changed in comparison with that observed at the diffraction trough infinite thin slit at the same distance (up to a registration plane) for given wavelength. Program module is created by Matlab program for simulation of the diffraction field trough an infinite slit. The experimental results are compared with the theoretical ones, obtained from the simulation. The simulation results shown, that at diffraction trough a slit with finite thickness, the registration distance of the far-field diffraction increases, i.e. the Fraunhofer zone may be drawn forward. The image of the object may be obtained in this case directly by inverse Fourier transformation from the registered data in the Fraunhofer zone.

DETERMINING LIFE OF HIGH POWER LIGHT EMITTING DIODES USING HIGHLY ACCELERATED LIFE TESTING A. Softi ¶, H. Smailhod ¢i¶ University of Tuzla, Bosnia and Herzegovina ABSTRACT The improvements in luminous efficiency, prolonged useful life, low–maintenance, and lowering of costs have enabled high power light emitting diodes (HP LED) to be used in more lighting applications. The increased use of LEDs as a primary light source means the demand for LED performance tests and reliability assertions is also increasing. For long life light sources, such as LEDs, evaluation and performance testing at nominal values is not a practical approach, since it can take years to determine the life. Thus developing methods of accelerated life testing is necessary. Here presented is a 138

method of accelerating life testing of LED using highly increased ambient temperature as a stress parameter. Data collected between 1,000 and 6,000 operating hours are used to extrapolate life beyond 6,000 hours.

OPTICAL AND HOLOGRAPHIC CHARACTERISTICS OF As-S-Se THIN FILMS K. Petkov 1, I. Vlaeva 2, I. Taseva 1, T. Yovcheva 3 and S. Sainov

2

Central Laboratory of Photoprocesses, Bulgarian Academy of Sciences, bl. 109 Acad. G. Bonchev Str., 1113 Sofia, Bulgaria 2 Central Laboratory of Optical Storage and Processing of Information, Bulgarian Academy of Sciences, bl. 101 Acad. G. Bonchev Str., 1113 Sofia, Bulgaria 3 Department of Experimental Physics, University of Plovdiv, 24 Tzar Assen Str., 4000 Plovdiv, Bulgaria ABSTRACT 1

The photo-induced changes in As-S-Se ternary glasses offer the possibility of using amorphous chalcogenide layers for high-density information storage, high-resolution display devices and fabrication of diffractive optical elements. In this paper we report results of the photo-induced changes in the optical properties of optically uniform thin As40S60-xSex films. The optical constants (n, k) and thickness, d as well as the optical band-gap, Egopt were determined by spectrophotometric measurements. Linear dependence on n and Egopt on the Se-content were observed. The influence of light on the dispersion parameters of thin chalcogenide films was demonstrated. The holographic properties of As40S30Se30 layers with different thickness were investigated applying a symmetrical two-beam scheme. As a light source a semiconductor laser (LeadLight Technol., Inc.) was used generated at 532 nm. The two beams were S-polarizated. The total intensity after spatial filtering and beam expanding was 10 mW/cm2. The diffraction efficiency kinetic was monitored with a 1.5 mW semiconductor laser 635 nm operated at Bragg reconstructed angle condition. Two different gratings were recorded with grating steps 0.5 Ìm and 1.5 Ìm, respectively. The observed diffraction efficiency was not very high, but signal – to – noise ratio was better than 100:1.

MULTILAYER COATINGS FOR UV SPECTRAL RANGE Ilko MILOUSHEV, Tihomir TENEV, Rumiana PEYEVA and Krassimir PANAJOTOV Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia 1784, Bulgaria ABSTRACT The coatings for UV spectral range currently play sufficient roles in the modern optical devices. At all the research of the multilayer coatings is extensive and one goal is to reduce their manufacturing coast. In this communication we will present our results on the preparation of reflective UV coatings. The used layers are from magnesium fluoride and lanthanum fluoride. The coatings with different layers number between 20 and 50 are experimentally investigated. The technology is thermal evaporation in high vacuum conditions. The obtained results for coatings spectral characteristics are compared with the numerical ones.

CORRECTION OF EMISSION SPECTRA OF LIGHT EMITTED ELECTROLUMINESCENT STRUCTURE FOR EMISSION QUENCHING Nikolay Petrov Takuchev Trakia University, Stara Zagora, Bulgaria ABSTRACT Brightness of the emission of electroluminescent light sources reduces over time of its exploitation. In connection with the assignment connected with an electroluminescent structure emission a large number of emission spectra had to be corrected for emission quenching. The spectra were obtained at different combinations of parameters of the alternate supply voltage – frequency and amplitude (electroluminescence of pre-puncture type). This work describes the method used to adjust the spectra to eliminate the impact of the quenching to the brightness of the emitting electroluminescent structure. 139

LASER EMISSION CONTROL BY MEANS OF RESONANT GRATINGS RESONANT DIFFRACTION GRATINGS S. Tonchev, A.V. Tishchenko

#,

O. Parriaux

#

Institute of Solid State Physics of the Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria #Laboratoire Hubert Curien UMR CNRS 5516, Saint-Etienne Université, France ABSTRACT Thanks to the development of integrated optics in the early seventies and of the microstructuring technologies in microelectronics it has become possible to generate new diffractive optical elements of the resonant type. The resonant character of the elements results from the association of a surface corrugation with an optical resonator in the form of a slab waveguide whose surface is corrugated or whose refractive index is periodically modulated. The optical resonator does not have to be a dielectric waveguide, it can also be a single dielectric-metal interface propagating a surface plasmon wave, the main requirement being that there are means provided to concentrate the field of a surface wave in the neighbourhood of the corrugation. As a result, the resonant corrugation (or index modulation) diffracts an incident free space wave more efficiently than a conventional corrugation and, more importantly, exhibits selectivity features in angle, wavelength and polarization which are absent in a conventional grating. Such resonant element is therefore a diffractive element which can advantageously be used as a multifunction filter in light processing. These functions are particularly useful in lasers where their selectivity characteristics can be used for the control of the emission. A practically attractive feature of such elements is that they are planar, therefore they can be associated monolithically with the laser mirror, and can be fabricated by low cost and highly reproducible batch planar microstructuring technologies.

PREPARATION AND EVALUATION OF CARRAGEENAN/CHITOSAN MULTILAYER BEADS M. Marudova-Zsivanovits a, G. Zsivanovits

b

a Department

of Experimental Physics, University of Plovdiv, 24 Tzar Assen Str. 4000, Plovdiv, Bulgaria, [email protected] b Agricultural Academy of Bulgaria, Canning Research Institute, Plovdiv, 154 Blvd. Vasil Aprilov 4000 Plovdiv, Bulgaria, [email protected] ABSTRACT Polyelectrolyte complexes (PEC) of chitosan and carrageenan were used for preparation of microbeads. The optimal conditions of complex formation – pH, ionic strength and molar ratio between the polyelectrolyte partners, were preliminary investigated by turbidimetry and viscometry. It was found that the yield of the complex is the highest at pH values where both of the partners were charged. Both chitosan and carrageenan were used as core of the beads and multilayers were deposited by layer-by-layer technique. The core of the beads was formed by capillary extrusion of chitosan solutions with polymer concentrations in the range 0.5-2 wt% in precipitation bath, containing NaOH. The size of the core beads were evaluated as a function of polymer concentration and respectively viscosity of the polymer solution. The viscosity of the solutions for bead forming was measured by rotational viscometer, cylinder in cylinder technique on concentration series. The diameter of the dry beads was investigated by digital micrometer. It depended on the number of adsorbed layers and on the viscosity of the solutions. Swelling behaviour and stability of the beads was investigated in dependence on the environmental changes – pH and ionic strength. The minimum values of the equilibrium degree of swelling were at the same pH where the complexation was maximal. The swelling behaviour was associated with the impact of the effective charged in polyelectrolyte network, exposed in solution. Rheological properties (hardness, elasticity) of dry and swelled beads were evaluated by Stable Micro Systems table penetrometer, with flat-plate compression test. These tests were carried out with low deformation speed, until the full rupture. The diameter of measure cylinder was chosen for much bigger then the diameter of beads. The different swellings caused differences in diameter, and elastic properties.

140

IONIC CONDUCTIVITY STUDY ON POLYCRYSTALLINe LiFeVO A. Kazakopoulos

1,

K. Chissafis

2

and O. Kalogirou

4

2

1 Department

of Electronics, T.E.I. of Thessaloniki, 57 400 Thessaloniki Greece 2 Department of Physics, Aristotle University of Thessaloniki, 54 124 Thessaloniki Greece Since the early 1960 research has been focused on LiMVO4 materials where M=Cu, Ni, Co, Zn, Cd, Mg and Be for uses related with ‘rocking chair’ batteries and humidity sensors. LiNiVO4 and LiCoVO4 which have been shown to have an inverse spinel structure have been patented as potential cathode materials for lithium cells. The synthesis of a novel polycrystalline layered ceramic oxide LiFeVO4 has been reported recently and a basic impedance study has been done at temperatures between 25 and 250 oC [1]. An electrical relaxation study in the compound LiFeVO4 has been done in [2]. The material was prepared with solid state reaction as proposed in [1,2].

X-ray diffraction study was carried out to confirm material formation. SEM photographs were taken and the average size of the grains was estimated to be 30 Ìm.TGA measurements revealed a 1.2 wt% weight loss in the temperature range between 25 and 125 oC. This weight loss was attributed to humidity desorption. A decrease in the material conductivity in the above temperature range from 25 to 125 oC was attributed to the loss of humidity. Impedance spectroscopy measurements were carried out on pellets of polycrystalline LiFeVO4 at temperatures from 25 to 500 oC at 25 o C steps at frequencies from 42 Hz to 1 MHz. Pellets of two different widths were used in order to isolate the conductivity phenomena associated with the material-metal contacts of the pellets. Equivalent circuits were drawn using the program EQUIVCRT.PAS [3] to fit the results of the measurements at each temperature level. Parts of the equivalent circuits were assigned to grain boundary (gb) conductivity and bulk conductivity using time constant arguments. From the equivalent circuits the Arrhenius plots are drawn and the activation energies associated with grain boundary and bulk phenomena are calculated. The impedance measurements of the material revealed that it displays clearly ionic conductivity over the temperature of 125 oC. The conductivity of the material below the 125 oC presents a decrease in conductivity as it is heated up to 125 oC. This decrease in conductivity is associated with the humidity desorption mechanism revealed in the TGA measurements. References [1] [2] [3]

M. Ram, R.N.P. Choudhary and A.K. Thakour, Advances in Applied Ceramics, 105 (2006) No3doi: 10.1179/174367606X104168 M. Ram, Materials Chemistry and Physics, doi: 10.1016/j.matchemphys.2007.12.020 Equivalent Circuit (EQUIVCR.PAS) Bernard A. Boukamp, University of Twente.

THE MICROSTRUCTURE AND HARDNESS OF HOT DIP GALVANIZED STEEL DURING WIRE DRAWING Shukri Klinaku

1,

Teuta Dilo 2, Naim Syla

1

1 University 2University

of Prishtina, Kosovo of Tirana, Albania

ABSTRACT The steel wire samples are hot-dip-galvanized. The zinc coating is preformed using the standard method. To recognize the behavior of the zinc coated steel wire during the submission to deformation, the wire samples are drawn on a machine designed for this aim and then investigated. In this research is represented the phase structure of the zinc coated samples. Afterwards the thickness of the layer and the hardness of the hot-dip galvanized steel depending on the drawing is represented.

141

ANALYTICAL INVESTIGATION OF BYZANTINE GLAZED CERAMIC OBJECTS FROM DURR ËS, ALBANIA PRELIMINARY RESULTS N. CIVICI * 1, T. DILO 2, F. STAMATI 3, A. HOTI 4 Centre of Applied Nuclear Physics, Faculty of Natural Sciences, University of Tirana, P.O.Box 85, Tirana, Albania, [email protected]; [email protected] 2 Department of Physics, Faculty of Natural Sciences, University of Tirana, Bul. Zogu I, Tirana, Albania 3 Institute of Folk Culture, Centre of Albanological Studies, Tirana, Albania 4 Institute of Archaeology, Centre of Albanological Studies, Tirana, Albania ABSTRACT 1

The excavations performed in the area of Durres have revealed a big number of glazed ceramic objects which are preserved at the archaeological museum. The objects covering a wide period from 11 to 17 century belong to different periods and types. The group belonging to the Byzantine period is composed mainly of wares of different sizes, shapes and decorations. The archaeological studies support the thesis that most of the objects are imported from different foreign centers but there are also indications for the existence of a local production activity. Although the glazed ceramic objects of Durres were widely studied from the archaeological point of view the present study represents the first attempt to investigate the materials used for their manufacture. The objective of this study was the characterization of the materials used for the ceramic body, the glaze and the identification of the pigments used for the colored decorations. Shreds from 22 glazed ceramic objects from the archaeological museum in Durres were collected. Most of the shreds (12 pieces) belong to the objects from the Byzantine period (12 – 14 cent.) with glazes of different colors and some of them decorated with the zgraphito technique. The other shreds represent protomajolica and majolica wares that according to the archaeologists belong to 13 – 17th centuries’ imports from Italy. In the group are also included 14 pellets prepared from fired clays collected in the area of Durres. The optical microscopy results indicate that most of the Byzantine objects were made of medium coarse clays and in some of them mineral inclusions were observed. The thickness of the glaze varies between 0.1 and 0.4 mm. In most of the cases the glaze is applied directly on the ceramic body but there are some shreds in which the glaze is applied on a white layer. The elemental analysis of the glaze material and ceramic body were performed by Energy - dispersive X-ray Fluorescence Spectrometry (EDXRF). The results indicate lead as a major constituent of the glaze material (Pb - 26 ÷ 31 %) and the presence of tin is observed in some objects. The increased presence of Fe in red, brown, yellow and black colored glazes can be an indication that Fe compounds have been used as pigments while Cu compounds should have been used in green colored glazes. The elemental analyses indicate that Ca rich clays were generally used for the preparation of the ceramic body. The application of Hierarchical Cluster Analysis on the concentration data of the shreds shows the existence of two different groups. The first includes mainly clays collected in the area of Durres while the shreds from the objects of Italian origin form the second group. The Byzantine glazed ceramics are distributed between these two main groups. On one side, these preliminary results can support the thesis for the existence of local production activity in Durres and on the other side can indicate that the imports of glazed ceramic objects were coming mainly from Italy.

APPLICATION OF ARTIFICIAL NEURAL NETWORK IN DIFFERENTIAL THERMAL ANALYSIS OF ORGANIC AND INORGANIC COMPOUNDS Özlem Ilgün

a

, Murat Beken

b

, Vilayet Alekberov

c

, Ye{im Özcanli

d

a Applied

Mathematics Department, Halic University, Findikzade, Istanbul, Turkey Mathematics Department, Halic University, Findikzade, Istanbul, Turkey c Physics Department, Yildiz Technical University, Davutpa {a, Istanbul, Turkey d Physics Department, Yildiz Technical University, Davutpa {a, Istanbul, Turkey

b Applied

ABSTRACT Thermal decomposition of organic and inorganic compounds are analysed by simultaneous differential thermal analysis (DTA) method. Also phase transitions and critical points are investigated. Additionally a computer model based on backpropagation multilayer feedforward artificial neural networks (ANN) are used for the stimulation and prediction of critical points and phase transitions of organic and inorganic compounds. Experimental data values and output values of artificial neural networks are compared. ANN predictions showed a considerably good result due to some unjustified data values and ANN predictions concured with each other. 142

PHOTOINDUCED CHANGES IN OPTICAL AND MECHANICAL PROPERTIES OF THIN Ge-S-AgI FILMS B. Monchev 1, V. Boev1 , P. Petkov 2, T. Petkova 1 1 Institute 2Department

of Electrochemistry and Energy Systems, BAS, Acad. G. Bonchev bl.10, 1113 Sofia, Bulgaria of Physics, University of Chemical Technology and Metallurgy, 8 Kl. Ohridski blvd., 1756 Sofia, Bulgaria

ABSTRACT Bulk materials from Ge-S-AgI system with various ratio of S/Ge = 1,2; 1,5; 2; 3 and AgI in amount up to 20 mol.% have been synthesized. The non-crystalline nature of the obtained samples has been verified by X-ray diffraction analysis. The glasses were further processed in form amorphous thin films by means of vacuum thermal evaporation technique. Basic physical properties of the films like microhardness and transmission have been studied. The layers were illuminated by an argon ion laser with energy (hn = 2.54 eV) greater than the band gap of the materials. Photoinduced changes observed in the chalcogenide films are due to rearrangement in the amorphous structure that affects the glass behaviors and largely the physical properties. The microhardness has been estimated across the layer thickness to define the film composition homogeneity. The optical parameters like refractive index, reflection coefficient of the glassy films have been established from the transmission spectra. Optical band gap has been calculated by means of two independent methods: from the Tauc plot _hÓ=B(EgTauc – hÓ)2 and by determination of Eg04 – the energy at the absorption coefficient _ =104 cm-1, obtained from _ vs (hÓ) plot. The composition dependence of the optical gap has been discussed in terms of Davis&Mot’s theory. Discussion about the structural transformation after illumination has been made in view of the previously reported FTIR data.

CALCIUM PHOSPHATE REINFORCED COATINGS WITH INCORPORATED DETONATIONALLY GENERATED NANODIAMONDS L. Pramatarova

a* ,

E. Pecheva a , E. Iacob b, L. Vanzetti b, P. Montgomery c, J.-P. Stoquert c , L. Jacomine d , T. Hikov a, D. Fingarova a, D. Mitev e

Institute of Solid State Physics, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria, *[email protected] b Materials and Microsystems, Fondazione Bruno Kessler, 38100 Povo-Trento, Italy c Institut d’Electronique du Solide et des Systèmes (InESS), ULP-CNRS, 67037 Strasbourg, France d Institut National des Sciences Appliquees de Strasbourg, 67084 Strasbourg, France e Space Research Institute, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria ABSTRACT a

During the past century, synthetic materials and devices have been developed to the point at which they can be used successfully to replace and/or restore function to diseased or damaged tissues. Calcium phosphate (CaP) ceramic materials, such as hydroxyapatite (HA), have been shown to enhance bone apposition to orthopedic implants; they do not form fibrous tissues, but instead an extremely thin, epitaxial bonding layer with existing bone. Many studies have focused on the production of HA as bulk material or as coating. On the other hand detonation - generated nanodiamond (DND; grain size of 4-6 nm) has become an attractive candidate for fundamental research studies since it is the hardest known material, it is biologically compatible, chemically inert, and resistant to chemical corrosion and wear. Inclusion of DND in a ceramic matrix is expected to produce composites possessing high stiffness and improved mechanical properties compared to the single-phase ceramic material. In the present study, DND reinforced CaP composite coatings have been successfully fabricated by biomimetic approach at physiological conditions, i.e. immersion in a mixture of simulated body fluid (SBF) and DND particles at 370C and pH 7.4. The morphology, elemental composition and structure of the composite coatings have been studied using SEM/EDX, coherence probe microscopy, XRD and RBS. Additionally, measurement of the elastic modulus and hardness of the composite coatings by nanoindentation test indicated that the mechanical properties are affected by the DND in the starting precursor material of SBF solution. Therefore, DND reinforced CaP composites are promising coating materials for loadbearing implants. Acknowledgements: This work was supported by two National projects: with the Bulgarian Ministry of Education and Science (TK-X-1708/2007) and the Agency of Innovation of Bulgaria (NIF 02-54/2007). NATO grant CBP.EAP.RIG.982693 and ANNA project (No 026134(RI3), Research Infrastructure Action under the FP6 “European Integrated Activity of Excellence and Networking for Nano and Micro-Electronics Analysis”) are also acknowledged. 143

EFFECTS of THE METAL ELECTRODE on DIELECTRIC CONSTANT of MgO NANOPARTICLES Fatih Dumluda ñ*, Didem Bakay, Ahmet Altindal Marmara University, Faculty of Science and Letter, Department of Physics, 34722, Göztepe, Kadiköy, Istanbul, TURKEY ABSTRACT Nanocrystalline MgO is a very important scientific and commercial material. Nano sized MgO powder is widely used as a catalyst in chemical industries and MgO thin films are used as buffer layers for superconducting and ferroelectric thin films. Because of this investigation of electrical properties of the MgO nanoparticles is important. In this study, effects of the metal electrode on dielectric properties of MgO nanoparticles were investigated. MgCl2.6H2O were dissolved in ethanol and aged for a long time under stirring. The particles were obtained by precipitation method. Crystal structure of particles was investigated using X-ray diffraction. In order to determine the electrical properties of the MgO nanoparticles, metal electrodes were deposited onto both sides of the MgO pellets using thermal evaporation method in high vacuum ( 0.005 are relatively dense in contrast to the ones deposited at lower R. For films with R = 0.005 the annealing process leads to ~6 % decrease of the initial thickness, while for those with R = 0.0003 the thickness change is about 25 %. XPS spectroscopy and Spectroscopic ellipsometry show that in a wide range of R (between 1 and 0.005) the deposited layers have a composition close to the stoichiometric one. Nevertheless, at smaller R an enrichment of the films with Si is observed. XPS spectroscopy reveals a difference between the annealed and controlled silicon rich SiOx samples. Both types of films show a splitting of the Si 2p XPS line, but in the control samples a substantial part of the excess Si is bonded to oxygen atoms forming a suboxide, while in the annealed sample a clearly separated peak corresponding to a second phase in a SiO2 matrix is observed. The as-deposited and the annealed layers were used as gate dielectrics in test MOS structures on n-type crystalline silicon. The C/G-V results demonstrate that the electrical properties of the SiOx films, regarding defect density in the bulk and at the oxide/c-Si interface, degrade with the decrease of R. For films with composition close to the stoichiometric one the annealing at 1000oC strongly improves the dielectric properties of all films regarding leakage current and defects at the SiO2/c-Si interface. The measured parallel conductance in such films is reduced upon annealing to values typical for high quality thermal SiO2. The obtained results demonstrate that there is a wide range of partial pressures for deposition of SiO2 films, which have excellent dielectric properties after thermal annealing. On the other the possibility to deposit SiOx films enriched with Si, which can be used as a starting material to grow silicon nanocrystals in a SiO2 matrix is also shown.

FREEZE OUT PHENOMENON ON PECVD GROWN BORON NITRIDE FILM IN MIS STRUCTURE Orhan ÖZDEMIR *, Bora BOZKURT, Deneb YILMAZER, Pinar GÖKDEMIR, Kubilay KUTLU Yildiz Techical University, Department of Physics, 34210 Esenler-Istanbul/TURKEY ABSTRACT Boron nitride (BN) is constituted by boron (a 3-A) and nitrogen (a 5-A) elements which are the nearest neighbors to carbon on either side in the periodic table. Some features of BN films are alike with carbon; one of them is its phase, namely hexagonal (h) and cubic (c). h-BN phase is similar to graphite as both are very soft and have a layered structure, but, unlike graphite, it has a very high electrical resistivity (along both a and c axes) and it is transparent for visible light. The other phase is cubic BN (c-BN) which is similar in bonding structure to diamond. However, h-BN is relatively easier to deposit in thin film form on large area with reduced cost by plasma enhanced chemical vapor deposition (PECVD) system as electronic material [1-2]. Owing to having high optical gap in the range of 5.0-6.0 eV [1-2], h-BN film is candidate for 159

optoelectronic applications as a UV-source or UV-detector. Moreover, it may be used in applications like photodetectors and cold cathode emitters because of the negative electron affinity. Additionally, high breakdown field (3-7)_106 V/cm and resistivity propose that h-BN film can serve as an insulating layer in thin film transistor structure. In this work, dielectric properties of PECVD grown BN film was investigated with admittance spectroscopy due to its charge sensitive properties by producing metal (Aluminum)/BN/p-type crystalline Silicon (MIS) structure. The ac admittance of MIS structures was measured in the frequency range of 1-1000 kHz. For each applied bias (from accumulating to inverting biases), the temperature (T) dependence of both capacitance (C) and conductance (G/ˆ) was determined to investigate majority/minority carrier behavior under the various frequencies (kHz-MHz) as parameters in the C (G/ˆ)-T-ˆ measurements [3]. Experimental analyses reveal that observed capacitance step and corresponding conductance peak is related to traps residing at the interface of insulator/semiconductor structure. On the other hand, surface band bending of silicon and activation energy (EA) deduced from the Arrhenius plot of the frequency vs. reciprocal temperature as a function of gate bias (VG) seem linearly dependent, implying that EA reflects the surface band bending variation. References: [1] Orhan Özdemir, Tamila Aliyeva-Anutgan, Mustafa Anutgan, _smail At_lgan, Bayram Kat_rc_o_lu, “Effect of heat treatment on stress and structure evolution in plasma deposited boron nitride thin films”, Surface and Coating Technology, 202(13) 3058-3066, 2008. [2] Orhan ÖZDEM_R, Mustafa ANUTGAN, Tamila AL_YEVA-ANUTGAN, _smail ATILGAN and Bayram KATIRCIO_LU, “Annealing Improvement on the Localized States of Plasma grown Boron nitride film Assessed Through Admittance Measurements”, Journal of Alloys and Compounds, 475, pp.794-803, 2009. [3] Orhan Özdemir, _smail At_lgan, Bayram Kat_rc_o_lu, “Similar admittance behavior of amorphous silicon carbide and nitride dielectrics within the MIS structure”, Vacuum, 82 issue 6, pp. 566-573, 2008. * Presenting Author

STUDY OF ORGANOSILICON PLASMA POLYMER USED IN COMPOSITE LAYERS WITH BIOMEDICAL APPLICATION E. Radeva a*, L. Pramatarova a, E. Pecheva a, T. Hikov a, E. Iacob b, L. Vanzetti b , R. Dimitrova c, N. Krasteva d , T. Spassov e , D. Fingarova a Institute of Solid State Physics, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria, *[email protected] b Materials and Microsystems, Fondazione Bruno Kessler, 38100 Povo-Trento, Italy c Institute Of Organic Chemistry with Centre Of Phytochemistry, 1113 Sofia, Bulgaria d Institute of Biophysics, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria e Sofia University, Faculty of Chemistry, Bulgaria ABSTRACT a

The ability of plasma polymer films obtained from hexamethyldisiloxane (PPHMDS) on stainless steel (SS) to induce composite layers from a mixture of simulated body fluid and detonation nanodiamond (DND) by biomimetic process was investigated. For this purpose, the growth of calcium phosphate (CaP) from the mixture on the polymer film was carried out. The FTIR spectra of the plasma polymers indicated a long chain branched polysiloxane structure depending on the different plasma conditions. Formation of CaP layers was also detected by FTIR after the immersion of the PPHMDS/SS in the mixture. In addition, XPS showed that the layers were carbon rich, which probably inhibited the transformation of CaP to hydroxyapatite. The topography of PPHMDS/SS coated with the composite layers was studied by AFM. The analysis revealed that their surface was rougher than that of the non-coated polymer. The DND suspension used in the experiment was tested for cytotoxicity by incubation of MG63 osteoblastic cells for 24 hours. It was observed that the cell morphology did not change significantly with the increase of DND concentration. In summary, the results showed that the polymer structure can be tailored by varying the plasma deposition conditions in order to use them in biomedical applications. Keywords : plasma polymer, detonation nanodiamond, calcium phosphate, biomimetic approach Acknowledgements This work was supported by two National projects: with the Bulgarian Ministry of Education and Science (TK-X1708/2007) and the Agency of Innovation of Bulgaria (NIF 02-54/2007). NATO grant CBP.EAP.RIG.982693 and ANNA project (_ 026134(RI3), Research Infrastructure Action under the FP6 “European Integrated Activity of Excellence and Networking for Nano and Micro-Electronics Analysis”) are also acknowledged.

160

INVESTIGATION OF THE RELAXATION TRANSITIONS IN POLYAMIDES V.G.Nikolskii, H. T. Polizov Institute of Chemical Physics, Academy of Sciences-Russia Plovdiv University “Paisii Hilendarskii” Department of Physics-Plovdiv, Bulgaria ABSTRACT The peaks in the relaxation region (intervals) for gamma-, beta- and alpha-transitions in polyamides PA-6 (VIDLON – BULGARIA), PA-11 (RILSAN – FRANCE) AND PA-12 (RUSSIA) using the method of the radio thermoluminescence (RTL) and the method of dynamic-mechanical losses- TAN DELTA MECHANICAL at the working frequency V = 1 Hz are obtained. The maxima due to the gamma-transition is the most intensive on the glow curves . The activation energies for each relaxation transitions are calculated using many Different methods for interpretation of the RTL-data.

INTRAGRANULAR CRITICAL CURRENT DENSITY IN YBCO SUBSTITUTED WITH Pr AND Ca A. Zahariev 1, 2 , E. Nazarova

1, 2 ,

K. Nenkov 2, 3 , T. Mydlarz

2

and V. Kovachev

1

1Institute

of Solid State Physics, BAS, 72 Tzarigradsko Chaussee blvd., 1784 Sofia, Bulgaria Laboratory of High Magnetic Fields and Low Temperatures, 95 Gajowicka, 53-529 Wroclaw, Poland 3IFW, Leibniz Institute for Solid State and Materials Research, 20 Helmholtzstrasse, D-01171 Dresden, Germany ABSTRACT 2International

The effect of magnetic (Pr) and non magnetic (Ca) chemical substitutions on the intragranular critical current, J intra, c , in polycrystalline Y 1-x-yPrxCayBa2Cu3O7-‰ samples is investigated. In principle two factors limit the Jintra, c: decoupling critical current density J0 ~ Hc/Ï (H c –thermodynamical critical field, Ï-London penetration depth) and pinning force. It is shown that at 4.2 K and low concentration (x=0.05, y=0 and x=0, y=0.025) both substitutions are almost equally effective and lead to Jintra, c higher than that for non substituted sample. This is a result of generated nanometric substitutional defects, which increased the pinning in both cases. The non magnetic, low valence Ca2+ substitution increases the carriers and leads to small overdoping, while magnetic (Pr3+) substitution only slightly deteriorates decoupling current. At high concentrations (x=0.20, y=0 and x=0, y=0.25) Jintra,c decreases in comparison with non substituted sample due to decoupling current suppression in both cases. It is established also that low Pr concentration gives the highest Jintra, c when the temperature is raised to 20 K.

INTEGRATING LIVING CELLS WITH POLYCRYSTALLINE SILICON: A BIOCOMPATIBILITY ASSAY E. Pecheva 1*, P. Laquerriere 2, D. Fingarova 1#, L. Pramatarova 1, T. Hikov 1 , D. Dimova-Malinovska 3, P. Montgomery 4 Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria; *[email protected]; presenting author 2 INSERM, ERM 0203 (labo des biomatériaux), IFR53, Reims, France 3 Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, Sofia, Bulgaria 4 Institut d’Electronique du Solide et des Systèmes, CNRS, Strasbourg, France ABSTRACT 1

#

Polycrystalline silicon (poly-Si) layers were bioactivated through the growth of hydroxyapatite (HA) - an inorganic material that is chemically similar to the mineral component of bones, teeth and hard tissues in mammals. Due to its excellent bioactivity and biocompatibility properties, HA is used as a coating of hard tissue implants (orthopedic, dental) in the human body, bone fillers, for drug delivery, and etc. The HA layer was grown on the poly-Si layers from a solution, resembling the human blood plasma, i.e. from a simulated body fluid. MG-63 osteoblast-like cells were then cultured on both HA-coated and non-coated poly-Si surfaces 161

for 1, 3, 5 and 7 days. Toxicity test showed that the cells survived on both groups of samples and their viability was over 95%. A permanent increase in the cell number with the time was observed, with more cells growing and proliferating on the HA-coated poly-Si. After 7 days of cell culturing this group of samples showed higher cell number, in agreement with the morphology results where the cells looked more compact. The electron microscopy images revealed also a lower cell adhesion on the poly-Si surfaces in the short term cell cultures (3 days). After 7 days of culturing, there were at least two monolayers of cells growing on the two groups of samples. This work revealed that the poly-Si layers were bioactive and biocompatible with the osteoblast-like cells. Nevertheless, the subsequent HA growth improved the cell interactions with the poly-Si surfaces based on the cell affinity to the specific chemical composition of the bone-like HA. Acknowledgements: This work was supported by grant TK-X-1708/2007 with the Bulgarian Ministry of Education and Science and NIF 02-54/2007 project with the Agency of Innovation of Bulgaria.

EFFECT OF COBALT SUBSTITUTION ON THE MAGNETIC PROPERTIES OF Ni – Cu FERRITE G. GOEV*, V. MASHEVA* L. ILKOV**, D. NIHTIANOVA*** *Faculty of Physics, “St. Kl. Ohridski”Univ. of Sofia, 1164-Sofia, Bulgaria, [email protected] **University of Technology, Sofia, Bulgaria, ***Central Laboratory of Mineralogy, BAS, Sofia, Bulgaria ABSTRACT Single-phase polycrystalline Ni0.85-yCu0.15CoxFe2O4 (x = 0, 0.02, 0.04 and 0.06) were synthesized by a standard ceramic technology. The mean particle sizes, obtained by SEM, vary between 2 and 8 mm. The main magnetic parameters such as saturation magnetization, remanence and coercivity were obtained from the entire hysteresis loops plotted in AC (2 kHz) magnetic field at room temperature. Hysteresis losses were evaluated from the same curves by using the Fourier decomposition. The initial permeabilities were obtained from the minor hysteresis loops, plotted in low enough magnetic fields. The remanence decreases almost linear with increasing Co-concentration. Both saturation magnetization and initial permeability have maxima at x = 0.02, but the coercivity and hysteresis losses have minima at the same Co-concentration. All the magnetic parameters, obtained at x = 0.02 are better than those of the starting composition with x = 0. The influence of the Co-substitution on the magnetic parameters is discussed.

PREPARATION AND CHARACTERIZATION OF HEXAKIS[2-METHOXY4-(2,3-DIMETHYLPHENYLIMINO)PHENYLATO]CYCLOTRIPHOSPHAZENE YASEMIN TÜMER A, BEKIR BAT_A ,HÜMEYRA BATI A, NEZIHE ÇALI}KANB AND ÇI∏DEM YÜKSEKTEPE B a Department

of Chemistry, Faculty of Arts and Sciences, Ondokuz Mayis University, 55139 Kurupelit, Samsun, Turkey bDepartment of Physics, Faculty of Arts and Sciences, Ondokuz Mayis University, 55139 Kurupelit, Samsun, Turkey ABSTRACT Hexakis[2-methoxy-4-(2,3-dimethylphenylimino)phenylato]cyclotriphosphazene was prepared by the reaction of hexakis[2-methoxy-4-formylphenoxy]cyclotriphosphazene and 3,4-dimethylaniline. The structure of new cyclotriphosphazene derivative was determined by, elemental analysis, IR, 1H-NMR, 13C-NMR spectra, thermal analysis and X-ray diffraction.

162

OPTICAL PHONONS OF NdBaCo 2O5+x : LATTICE DYNAMICS CALCULATIONS N. D. Todorov 1, M. V. Abrashev 1, V. G. Ivanov 1, E. Vlakhov 2 2

1 Faculty of Physics, University of Sofia, 1164 Sofia, Bulgaria Institute of Solid State Physics, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria

ABSTRACT → Optical phonons (k ≈ 0) of the double perovskite NdBaCo2O5+x are calculated in the cases of, x = 0, 1 (tetragonal P4/mmm, · = b = ·p, c ≈ 2·p) and x = 0,5 (orthorhombic Pmmm, · = ·p, b = ·p, c ≈ 2 ·p ) using the shell model. The calculated modes in the three crystal structures are classified according to their symmetry and frequency. By analyzing the eigenvectors for different modes the most intense bands in the Raman spectra of the complex compound NdBaCo2O5.5 are predicted. The results of the calculations are compared with the available experimental data.

THE COMPARISON OF STRESS OF (As 2S 3)1-x (AgI) x THIN FILMS PREPARED BY VACUUM THERMAL EVAPORATION (VTE) AND PULSED LASER DEPOSITION (PLD) K.Kolev1, T.Petkova 1, C.Popov 2, I.Mihailescu

3

Institute of Electrochemistry and Energy Systems (IEES), Bulgarian Academy of Sciences Institute of Nanostructure Technologies and Analytics (INA), University of Kassel, Germany 3 National Institute for Lasers and Radiation Physics, Buchares-Magurele, Romania

1 2

ABSTRACT The preparation of thin films with a good quality and desired composition can be a challenge in terms of their easy production and reproducibility. The preparation techniques of thin chalcogenide films can strongly influence structure, surface and physico-chemical properties of obtained films. The differences in prepared thin films can limit or on the other hand support their possible applicability. The film stress appears during the deposition process as a result of different thermal expansion coefficients of the film and the substrate, intrinsic residual thermal strains and structural rigidity. High stress values can cause a number of negative consequences, e.g., bending of the film-substrate interface, peeling, cracking, etc. Thin films from the (As2S3)1-x (AgI)x system have been prepared by vacuum thermal evaporation (VTE) and pulsed laser deposition (PLD) from the corresponding bulk glasses. The film structure and surface morphology have been studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The investigated chalcogenide films are amorphous as revealed by XRD, featureless and with smooth surfaces viewed from the AFM pictures. The stress measurements of the thin films deposited on special silicon cantilevers have been carried out by cantilever bending technique. The obtained results have been discussed with respect to the film composition and structure. Different behavior depending on the deposition technique occurred in the pure As2S3 samples, showing compressive stress for PLD and tensile for VTE. The addition of AgI leads to versatility of the changes in VTE and PLD films. The tensile stress is reduced and turned it to compressive for higher AgI concentrations by VTE while the PLD films possess compressive stress, which increases with addition of AgI. Very well expressed relaxation in PLD films occur while for the VTE films the tensile stress is slightly lower in the compressive region after 3 months.

THERMAL STUDIES OF Ge-Te-Ga GLASSES P. Petkov 1 , P. Ilchev 2, V. Ilcheva 3. T. Petkova 3 1 Department

of Physics, University of Chemical Technology and Metallurgy, 1756 Sofia, Bulgaria 2Central Laboratory of Photoprocesses, BAS, 1113 Sofia, Bulgaria 3Institute of Electrochemistry and Energy Systems, BAS, 1113 Sofia, Bulgaria

ABSTRACT Bulk glasses of (GeTe4)1-xGax and (GeTe5)1-xGax (x = 0, 5, 10, 15 mol. %) systems have been prepared by melt-quenched technique. Differential Scanning Calorimetry (DSC) analysis has been performed to study the thermal stability of the glasses. The values of the glass transition temperature (Tg), the crystallization onset temperature (Tc, onset), the 163

crystallization peak temperature (Tc) and the melting temperature (Tm) have been determined. The thermal stability of synthesized glasses has been evaluated by some criteria. The estimated values of these criteria show an improvement of the glass forming tendency and the thermal stability of the glasses with the introduction of gallium up to 15 mol.%. Consequently, the positively influence of the gallium as network modifier over the thermal characteristics has been proved. The thermograms of the samples illustrate an increased Tg of the glasses as gallium content increases. As a rule this identifies an increased stability of the glasses. The distance Tg-Tcr as definition of the glass stability is found to be almost constant and the distance between Tm and Tcr is found to decrease and thus the strength of the Ge-Te-Ga glasses is confirmed. The crystallization peaks of most of the samples are broad and suggest that at temperatures higher than 500 K probably more than one compound is crystallized. In the binary glasses the crystallization temperature registered about 500 K reveals the crystallization of the metastable GeTe2 phase as reported by several authors. This phase melts with decomposition seen by presence of shoulder of the melting peak. The broadening of the crystallization peak in the ternary glasses notifies co-crystallization of a number of phases. The melting peaks are for the most of the samples more than one and they presume the melting of the various crystallized phases. As can be noticed the melting points are very close in values and the first peak can be attributed to the one and same phase. Thermo-induced crystallization of the synthesized bulk materials of Ge-Te-Ga system has been carried out and X-ray diffraction measurement has been performed to elucidate the phases attained after heating up to 573 K. The introduction of gallium is related to appearance of new stable phase of Ge2Te3 however no ternary phases are visible in the crystallized samples. A second phase of Ga2Te5 appears additionally to the Ga2Te3 phase when the gallium content grows and reaches 20 mol.%. In the GeTe 5 system in some cases unknown peak has been observed. We presume the unknown peak could belong to the remnants of metastable GeTe2. This peak is seen also in samples without gallium and with small amount of gallium however it diminishes in the sample with 20 % . The existence of metastable phase of GeTe2 has been reported by many authors. When the temperature increases up to 523 K, GeTe2 decomposes in GeTe and Te. The described changes of the characterization temperatures could be explained with structural transformation as a result of the addition of gallium to the chalcogenide matrix. The introduction of third component Ga, probably improves the stability of the Ge-Te system. The increase of the average coordination of the system by means of formation of new structural fragments, leads to increase of Tg, which is directly proportional to the average bond energy , that is measure of the glass stability. Thermocristallization experiment shows, that the chalcogenide glassy materials from the both systems GeTe4 and GeTe5 are composed of identical crystallized phases, together with amorphous phase.

BACTERIAL BIOSYNTHESIS OF HYDROXYAPATITE ON METALLIC AND POLYMERIC SUBSTRATA R. L. Sammons a, L. Pramatarova b, A. Wang c, A. Wright d , W. Palin a, J. Wilson a, L. Macaskie e , P. Yong e, E. Pecheva b, E. Radeva b and T. Spassov f a School of Dentistry , University of Birmingham, Birmingham B4 6NN, UK Institute of Solid State Physics, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria c School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT d School of Chemistry, University of Birmingham, Birmingham B15 2TT e School of Biosciences, University of Birmingham, Birmingham B15 2TT f Faculty of Chemistry, University of Sofia, Bulgaria b

ABSTRACT The bacterium Serratia NCIMB 40259 is capable of forming hydroxyapatite on substrata on which it grows as a biofilm. The production of calcium phosphate is driven by an acid phosphatase enzyme located in the bacterial cell wall, on fimbriae and within the bacterial extracellular polymeric matrix. CaP may be obtained by two methods: In the first, crystals of CaP are formed extracellularly within the pre-formed bacterial biofilm grown on the substrata. In the second method, planktonic bacteria catalyse the formation of CaP in suspension and on solid substrata placed in the same container. In this work we report the use of both methods to form CaP on a variety of substrata including pure titanium and titanium and zirconium alloys and polymers, with and without detonation-generated nanodiamonds. The morphology and characterisation of the CaP layers and precipitates by SEM, FTIR and XRD are described. Acknowledgements: This work was supported by the Bulgarian Ministry of Education and Science (TK-X1708/2007) the Agency of Innovation of Bulgaria (NIF 02-54/2007). NATO grant CBP.EAP.RIG.982693, ANNA project (NÔ 026134(RI3), and a UK Royal Society International Travel Grant (BIR002).

164

PHYSICAL BEHAVIOURS IN GE-SE- IN GLASSY CHALCOGENIDES A.Stoilova 1 , P. Petkov 1, T. Petkova 2 1 Thin

Films Technology Lab,Department of Physics, University of Chemical Technology and Metallurgy, 8 Kl. Ohridski blvd., 1756 Sofia, Bulgaria 2 Institute of Electrochemistry and Energy Systems, BAS, Acad. G. Bonchev bl.10, 1113 Sofia, Bulgaria ABSTRACT Chalcogenide glasses of (GeSe4)1-xInx, (GeSe 5)1-xInx and (GeSe 6)1-xInx, with 5,10,15,20 mol % In have been investigated. Basic physical characteristics have been obtained: density (r), compactness (d), molar volume (Vm). Heaver In atoms decrease the interatomic distances and hence of the glass connectivity increases. When indium reaches 10 mol. % the raise in the density curve stops, in some cases the density values decrease as obtained in the (GeSe5)1-xInx system. The changes in V correspond to changes in the measured density of these glasses. The strength of the chemical bond is associated with the compactness of the material and the compactness depends on the density of the defects in the sample. Transitions in the behaviors according to the theory could expect in the range of Z numbers 2,4-2,46. In the GeSe4 system maximum in density and minimum in the molar volume values has been obtained in the composition with 10 mol.% In which corresponds to coordination number 2,46. In the GeSe5 and GeSe6 extreme values in both behaviors are seen at lower coordination number – 2,4 and 2,36 respectively. The trend in the behaviours depends on transitions in the structure and rearrangement. In chalcogenide glasses atoms have preference to combine predominantly with atoms of different kinds than with the same kind and this condition is equivalent to assuming the maximum amount of possible chemical ordering. Bonds are formed in the sequence of decreasing bond energies until all available valences for the atoms are saturated. In GeSe4 system bonds are realized by the tetrahedral formations and In atoms are supposed to link to the Se atoms from the tetrahedrons. In GeSe5 and GeSe6 bonds in tetrahedrons are formed and there are still unsatisfied Se valences that create Se- Se bonds. The addition of In decreases the number of homopolar Se bonds, i.e. increases the stability of the system however these bonds are longer compared to the Se-In bonds from the tetrahedrons. The experimental obtained parameters, density, molar volume are included in the calculations of the free volume in the samples. The correlation between free volume percentage (FVP) and mean coordination number (Z) has been discussed. For the system GeSe4 and GeSe5 the FVP shows minimum at 2,46 in the GeSe4 system and GeSe5 – at 2,4. The correlations between the composition and properties of the glasses are discussed with the view of glass structure.

ASSESSMENT OF ELECTRICAL BEHAVIOR OF NON-WOVEN TEXTILE MATERIALS Dragana D. Cerovic, Jablan R. Dojcilovic*, Koviljka A. Asanovic**, Tatjana V. Mihailovic**, Tatjana A. Mihajlidi** The College of Textile Design, Technology and Management, Starine Novaka 24, Belgrade, *Faculty of Physics, University of Belgrade, Studentski trg 12, Belgrade, **Faculty of Technology and Metallurgy , University of Belgrade, Karnegijeva 4, Belgrade ABSTRACT Non-woven textile materials have been increasingly used for a variety of applications in industry and daily life. This imposes a need for the investigation of electrical properties in different conditions of their usage. In the scope of this investigation, electrical conductivity and dielectric properties such as relative dielectric permeability and dielectric loss tangent of various polyester non-woven textile materials were determined. Experimental values of frequency were in the limits of 80 kHz to 2 MHz at relative environmental humidity of 30%. In addition, aimed at discovering the behaviour of investigated material from the aspect of electrical conductivity in various conditions of environmental humidity, the electrical conductance was measured both at 30% and 80% of relative environmental humidity in the electric periodic field at the frequency of 1 MHz. All measurements were realised at the temperature of 30ÆC. Obtained results showed that with the increase of freqency of electric periodic field electrical conductivity of tested samples increases, while the values of dielectric properties decrease. Furthermore, it was found that the increase of relative environmental humidity provokes the increase of electrical conductivity of tested non-woven samples.

165

THE BYZANTINE CHURCH OF “40 HOLY MARTYRS” IN VELIKOTURNOVO, BULGARIA: PIGMENTS AND TECHNIQUE E. Sakellariou 1, T. Zorba 1, E. Pavlidou 1,S. Angelova 2, K.M. Paraskevopoulos 1 Physics

1

Dept. Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece 2Dept. of Archeology, Univ. of Sofia, Sofia, Bulgaria

ABSTRACT The “St. 40 Martyrs” church is the most famous medieval building in Veliko Turnovo, Bulgaria. It is located in Assenova mahala, just next to Tsarevets. It was built and its walls were painted during the reign of Bulgarian king Ivan Assen II after the victory against Epyrus despot Theodor Comninos (1230 AD). It consists of two buildings - a six-column basyllic and another, smaller building on its western wall, which was built later. During the presence of the Ottoman Turks, maybe until the first half of the 18th century, the church remained christian. When it was converted to a mosque, all the christian symbols in it were destroyed. The archeological researches on site were initiated in 1969. As it is clear the 40 Martyrs church, is a historical monument of culture with great significance. The church had murals, from the earlier period, but in the following years and especially during the Ottoman period, the church has suffered many and different destructions. Nevertheless, the very few pieces of murals that are rescued till nowadays provide important information for the technique and the pigments that were used on its wall paintings. In the present work, twelve series of samples from the wall paintings were studied in order to characterize the materials and the technique used for church iconography. The study was based on the micro-analytical techniques of the Fourier Transform Infrared micro-spectroscopy (Ìs-FTIR), the Optical Microscopy and the Scanning Electron Microscopy (SEM) coupled to an Energy Dispersive X-ray Spectrometer (EDS). In the FTIR spectra of all pigments the characteristic peaks of calcite were detected, confirming the use of fresco technique for the creation of murals. The combination of FTIR spectroscopy and SEM-EDS analysis, reveal the existence of lapis-lazuli for the blue color, green earth for the green color, cinnabar for the red color, calcite for the white color and carbon black for the black color. Moreover, in other chromatic layers, the presence of iron oxides (hematite and limonite) indicating the use of ochre for the yellow and red pigments, is identified. Finally, the surface of some samples was covered by a transparent and tensile material. This material was characterized by Ìs-FTIR spectroscopy as an organic substance, probably a natural resin that was used to protect the murals in the early ages.

SYNTHESIS, CRYSTAL STRUCTURE PROPERTIES OF (Z)-N’-((E)-2(HYDROXYIMINO)-1-PHENYLETHYLIDENE)ISONICOTINOHYDRAZIDE AY}IN ZÜLFIKARO ∏LU A, HÜMEYRA BATIA, ÇIŒDEM YÜKSEKTEPE B, NEZIHE ÇALI}KANB, AND ORHAN BÜYÜKGÜNGÖR B a Department

of Chemistry, Faculty of Arts and Sciences, Ondokuz Mayis University, 55139 Kurupelit, Samsun, Turkey b Department of Physics, Faculty of Arts and Sciences, Ondokuz Mayis University, 55139 Kurupelit, Samsun, Turkey ABSTRACT Compound (I) contains three moieties, namely pyridine, monoxime and hydrazone and a non-merohedral twin crystal with two reciprocal lattice differently oriented giving rise to double diffraction spot sets with the 0.5:0.5 ratio of the twin components. The hydrazone and oxime units are approximately planar. The dihedral angles between this plane and the planes of the pyridine and phenyl units are 30.79(19)Æ and 18.43(13)Æ, respectively. Both the oxime and hydrazone units in (I) have an E configuration. The organic molecules of (I) are linked via C_H...O and O_H...N hydrogen bonds forming a three-dimensional framework. The structure of compound characterized by means of, IR, 1H NMR, spectra, elemental analyses and X–ray diffraction techniques.

166

CRYSTALLOGRAPHIC FEATURES OF THE MARTENSITIC TRANSFORMATION IN PbTiO 3 COMPOUND N. Navruz Department of Physics, Faculty of Sciences, Ankara University, Tandogan, 06100 Ankara, Turkey ABSTRACT Martensitic transformations are displacive in nature and occur in the solid state in a wide variety of metallic and non metallic materials. Although the occurrence of martensitic transformations in inorganic and ceramic compounds has been well recognized for many years, it is only in the last decade that they have achieved prominence. An important group of materials in which Martensitic transformations play a significant role in determining microstructure and thus properties are the perovskitetype oxides such as PbTiO3. In this study, emphasis is given to the crystallography of the paraelectric cubic to ferroelectric tetragonal phase transformation in PbTiO3 compound. A detailed crystallographic analysis is performed in Lead Titanate (PbTiO3) and the crystallographic parameters are calculated. The predictions of the crystallographic analysis are compared with the experimental results available and good agreement is found between calculated results and experimental observations.

THE STUDY ON AC SUSCEPTIBILITY GRAINED MODEL FOR THE HIGH-TC SUPERCONDUCTOR Bi-2223 O. Ozogul Department of Physics, Faculty of Sciences, Ankara University, Tandogan, 06100 Ankara, Turkey ABSTRACT The magnetic properties and the current transport of High-Tc ceramics are governed not only by the nature of diamagnetic grains but also by their interconnections which constitute the superconducting matrix. Such a sintered High-Tc Superconductor has two effects. One is intrinsic to the superconducting grains and the other is characteristic of the coupling between grains. These phenomena have been widely studied in order to understand the mechanisms governing the flux lines dynamic within critical-state models. While the original Bean model of the critical-state only predict single characteristic in the imaginary part of the fundamental susceptibilities, grained Bean model, where the superconducting grains are immersed in weak superconducting matrix, predicts the typical double peak appear in the imaginary part and double transitions in the real part. The predictions of the grained Bean model for the field and temperature dependencies of the ac magnetic susceptibilities are compared with experimental results.

MODEL SIMULATION OF DEFECT DIAMOND INDENTATION IN CLUSTER APPROACH O.V. Khavryuchenko 1, V.D. Khavryuchenko 2 , V.V. Lisnyak

1

2Institute

of Sorption and Problem of Endoecology, National Academy of Sciences of Ukraine, 13 General Naumov Str., 03164 Kiev, Ukraine; e–mail: [email protected] 1 Kyiv National Taras Shevchenko University, 64 Volodymyrska Str., 01033, Kyiv, Ukraine. Tel: (044) 2393306; Emails: [email protected], [email protected] ABSTRACT Theoretical prediction of mechanical properties of solids, particularly of stress moduli, is a great challenge. Convenient methods of simulation, including molecular mechanics or molecular dynamics and infinite solid state approaches, lack some crucial points, which allow anticipation of local chemical processes, occurring upon external mechanical stress. However, some of these disadvantages can be overcome within quantum chemical (QC) methods in cluster approach. In this work a model simulation of nanoindentation process has been performed in the framework of PM3 [1] QC method (“QuChem” program set [2,3]). The indentation of hydrogen-saturated diamond cluster C190H110 and a set of defective clusters C189H110 with smaller C84H60 diamond cluster has been simulated in order to find structural changes and to evaluate energetic profile of mechanical interaction of nanoclusters. The work is illustrated with simulation animations. 167

[1] J.J.P. Stewart, J. Comp. Chem. 10 (1989) 209. [2] V. Khavryutchenko, Eurasian ChemTech. J. 6 (2004) 157. [3] V.D. Khavryuchenko, Y.A. Tarasenko, V.V. Strelko, O.V. Khavryuchenko, V.V. Lisnyak, Int. J. Modern Phys. B 21 (2007) 4507.

LOW-DIMENSIONAL POSITIVE ELECTRODE MATERIALS V.V. Lisnyak Kyiv National Taras Shevchenko University, 64 Volodymyrska Str., 01033, Kyiv, Ukraine. Tel: (044) 2581241; E-mail: [email protected] ABSTRACT Some of low dimensional compounds can exhibit electronic instabilities towards charge density wave (CDW) states. One of the most investigated classes of such CDW-conductors is a family of transition metal oxides, which includes phosphate bronzoides. Layered crystal structure and confinement of d-electrons in the middle of the layers make these bronzes quasi two-dimensional conductors. This anisotropy, associated with the presence of a large nesting of the Fermi surface and a strong electron-phonon coupling leads to the CDW instabilities. Among quasi two-dimensional conductors monophosphate and diphosphate bronzes (Mx(PO2)4(TO3)2m and Mx(P2O4)2(TO3)2m, where m ≤ 16, T = W, Nb and x is variable x ≥ 0) are a particular challenge due to the unpredictability of the ground states of correlated electron systems, and the bronzes frequently occurring sensitivity to small changes in chemical composition and physical conditions. In this work the main results obtained during the electrochemical and chemical lithium- (sodium-)insertion in the family of phosphate tungsten and niobium bronzes Mx(PO2)4(TO3)2m and Mx(P2O4)2(TO3)2m, where 2 ≤ m ≤ 10, M = vacancy or mono, divalent metals, T = W, Nb and x is variable x ≥ 0) has been reviewed. This family of complex oxides is a prospective model to study the relation between the electrochemical properties and processes observed in the course of lithium, sodium insertion and the changes of bronzes structures. Structural changes in the bronzes were observed as insertion proceeded. The nature of inserted phases has been elucidated by means of X-ray diffraction experiments and a correlation with the reversible/irreversible processes observed during the electrochemical insertion has been determined. The electrical properties of the Li- and Na-inserted phases were measured and a relation with the amount of lithium or sodium inserted and m was found. The different processes which take place at the cathode during the discharge of the cell were comprehensively analyzed using potentiostatic intermittent technique. Electrochemical lithium and sodium insertion into bronzes between 7.4 and 0.5 V vs. Li+/Li0 and 5.6 and 0.1 V vs Na+/Na0, has allowed the determination of several phases. Measurements of resistivity show that the metallic phosphate tungsten and niobium bronzes become insulating upon lithium or sodium insertion at high loads. Electrochemical systems reach high specific capacity of the cell up to 700 A⋅h/kg at the first cycle, but the through the following cycles the specific capacity drastically decreases down to 175–250 A⋅h/kg due to irreversible processes.

ELECTRICAL CHARACTERISTICS OF Al/SiO 2/s-Si/Si 1-x Ge x MOS STRUCTURES AS A FUNCTION OF STRAINED-Si OVERLAYER N.Kelaidis a ,V.Ioannou – Sougleridis a, D.Skarlatos b, K.Papagelis c J.Parthenios, d S.N.Georga b, C.A.Krontiras b,*, Ph.Komninou e, C.Tsamis a, B. Kellerman f and M. Seacrist f a) Institute of Microelectronics, NCSR “Demokritos”, 153 10 Aghia Paraskevi, Athens, Greece b) Department of Physics, University of Partas, GR-265 04 Partas, Greece c) Department of Materials Science, University of Partas, GR-265 04 Partas, Greece d) Foundation of Research and Technology Hellas, Institute of Chemical Engineering and High Temperature Processes, GR-265 04 Patras, Greece e) Department of Physics, Aristotle University of Thessaloniki, 541 24 Thessaloniki Greece f) MEMC Electronics Materials, Inc, 501 Pearl Drive (City of O’Fallon) St. Peters Missouri 63376, USA * corresponding author : [email protected] ABSTRACT Conventional scaling, the core of semiconductor technology evolution, has lately become increasingly challenging, as devices are approaching atomic dimensions. In order to maintain the pace of Moore’s Law, research is focused towards the use of alternative materials of higher mobility than Si, as a way of increasing device performance without further decrease of the device dimensions. Such a material, is strained-Silicon (s-Si),which already replaced Si from the 90 nm CMOS technology node. The study of the structural and electrical properties of s-Si MOS (Metal-Oxide-Semiconductor) structures with ultrathin 168

gate dielectrics is of critical importance especially as a function of the strained –Si overlayer, where a variety of phenomena remains under investigation. This is the main target of the present work. For this purpose ultrathin oxides formed in 100% N2O ambient will be used as gate dielectrics. Si oxynitridation in N 2O ambient leads to the formation of ultrathin oxides at high temperatures, thus enabling a parallel study under high thermal budget conditions. The strained- Si structures used in the present study consist of a 27.5 or 13 nm thin Si overlayer epitaxially grown on relaxed constant composition Si0.9Ge0.1 and Si0.78Ge0..22 substrates respectively. Prior to oxynitridation part of samples from both structures were chemically etched in order to obtain a variety of s-Si overlayers . Oxynitridation has been performed at 800 oC – 9000C for various time intervals. Ramman spectroscopy and Transmition Electron Microscopy (TEM) have been used in order to study strain preservation and the remaining s-Si overlayer after the etching and oxidation processes. SIMS analysis was performed for the study of Ge out diffusion from Si1-xGex towards the SiO2/Si interface. The electrical properties of the structures have been studied by the formation of MOS capacitors with Al as gate metal. Combination of the above mentioned measurements indicate that as the s- Si overlayer decreases, the two existing interfaces, the SiO2/s-Si and the s-Si/Si1-xGex, of the structures contribute in parallel to the electrical characteristics of the dielectrics. This contribution seems to be affected also by the thermal budget of the oxynitridation process.

CREEP OF A SOLDER ALLOY Sn-Ag-Cu E. Duka 1, H.Oettel 2, T. Dilo 3 2-

1-Universitety ‘’ A. Moisiu’’ Durres Albania [email protected], Technical University Bergakademie, Freiberg, Germany, [email protected] 3-University of Tirana, Albania [email protected];

ABSTRACT To describe the creep behaviour of metallic materials mainly a power law firstly given by Norton like dÂ/dt = A Ûn exp(Q/R T) is used (Â - creep strain; Û - applied stress, A – scaling parameter; Q – activation enthalpy). The creep theory shows us, that the exponent n depends on the mechanism of creep (dislocation creep, Coble – creep or Nabarro – Herring – creep). For a soldering alloy Sn-Ag-Cu (95.5% Sn, 3.8% Ag, 0.7% Cu) these parameters were determined by an impression creep test. As confirmed by x-ray diffraction the microstructure is characterized mainly by a Sn-solid solution and an intermetallic Sn - Ag - compound. According to the liquidus temperature of these phases we can conclude, that creep takes place mainly in the Sn-solid solution. The values of n we have found from our creep experiments amounts between 1.8 and 2.9. Based on the experimental values of n we can conclude that the main mechanisms of creep are dislocation mechanisms. The activation energies experimentally founded are in the range between Q/R=2363 and Q/R=5761. The A-parameter increases with the increase of the contact area, with the decrease of Q-activation energy and with the decrease of nexponent creep stress. It is shown in the creep experiments that the results depend slightly on the impression body diameter.

SIMULATIONS OF STRAIN ON THE ELECTRONIC PROPERTIES OF SEMICONDUCTING SWCNTs: ORDER N, PARALLEL, TIGHT-BINDING MOLECULAR DYNAMICS TECHNIQUE Gülay Dereli*, Necati Vardar and Önder Eyecio

ñlu

Department of Physics, Yildiz Technical University, Istanbul 34210, Turkey ABSTRACT Single Wall Carbon Nanotubes (SWCNTs) have attracted wide attention for application to nano-devices due to their unique mechanical and electronic properties. What is so special about SWCNTs is that their electronic, thermal and structural properties can change with diameter, length, and chirality (1-3). The conductivity of Single Walled Carbon Nanotubes (SWCNT) is mostly determined by the chirality of the tubes. Depending on their chirality, they could be metal or semiconductor. Electrical conductivity of SWCNTs may also change due to deformations such as uniaxial strain. In this study, we will report on the electronic properties of the zig-zag single-walled carbon nanotubes (SWCNTs) with 1.5nm diameter under uniaxial strain. During our simulations we used the parallel, Order N Tight-Binding Molecular 169

Dynamics technique which is improved and successfully applied to SWCNT simulations by Dereli and co-workers(3-6). Deformations such as uniaxial compressive or tensile strain modifies the band gap of the nanotubes. Under such deformations zig-zag single-walled carbon nanotubes undergo semiconductor-metal-semiconductor transitions. Our studies also show that such transitions depends on the geometry of the zig-zag SWCNTs. The research reported here is supported through the Yildiz Technical University Research Fund Project No: 24-01-0104. The simulations are performed at the Carbon Nanotubes Simulation Laboratory at the Department of Physics, Yildiz Technical University, Istanbul, Turkey(7). [1]B.Onat, M.Konuk, S.Durukanoñlu and G. Dereli , Nanotechnology 20 ,075707, (2009). [2]G. Dereli , B.Süngü, Phys. Rev. B 75, 184104, (2007). [3]G. Dereli , B.Süngü, C. Özdoñan,, Nanotechnology 18 , 245704, (2007). [4]G. Dereli , C. Özdoñan, Phys. Rev. B 67 , 0354416, (2003). [5]G. Dereli , C. Özdoñan, Phys. Rev. B 67 , 0354415, (2003). [6]C. Özdoñan, G. Dereli , T. Çañin, Comp. Phys. Comm. , 148, 188-205, (2002). [7]http://www.yildiz.edu.tr/~gdereli/lab_homepage/index.htm

THERMAL DEGRADATION KINETICS OF PBSu/SiO Antoniadis G.

1,

Paraskevopoulos K.M.

1,

Bikiaris D.N.

2 2,

NANOCOMPOSITES

Chrissafis K.

1

1Department 2Department

of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.

ABSTRACT A series of nanocomposites that consisted of poly(butylene succinate) (PBSu) and fumed silica nanoparticles (SiO2) were prepared by in situ polymerization. Thermal degradation of these nanocomposites was studied following their mass loss during heating. Thermogravimetric measurements were performed with a SET∞RAM SETSYS TG-DTA 16/18 system. The mass loss curves of all studied samples at a heating rate of 10oC/min are presented in Fig. 1. It can be seen that PBSu and PBSu/SiO 2 nanocomposites present a relative good thermostability since the maximum mass loss that occurred until 275oC is smaller than 0.5%. At this temperature, only for in the sample PBSu with 5wt% SiO2, can be identified a slight increase of the observed mass loss (0.7%) instead of 0.5% in the other samples. For the determination of the activation energy (E) the Ozawa–Flynn–Wall (OFW) and Friedman isoconversional methods are used, and the results of the two methods are shown in Fig. 2 for the studied PBSu/SiO2 nanocomposites. From the plots it can be seen that although the shape of the curves is almost the same, significant differences can be recognized at the activation energy values for the same value of partial mass loss. The differences in the values of E calculated by the OFW and Friedman methods, for the same sample, can be explained by a systematic error due to improper integration. It is clear from the plots that the mean values of the activation energy of PBSu are different from those of its nanocomposites. From the variations of activation energies calculated from thermogravimetric curves it is clear that the nanocomposites containing 1wt% SiO2, presents higher activation energy compared with neat PBSu, which is an indication that the addition of nanoparticles can increase slightly the thermal stability of PBSu matrix. However, in PBSu/SiO2 nanocomposites with 5 wt% SiO2 content, the activation energy is smaller. This phenomenon can attributed to the existence of extended branched and crosslinked macromolecules, which reduce the thermal stability of PBSu, rather than the silica addition.

170

Figure 2. Dependenceof the Activation Energy (E) on the degree of the partial mass loss (·), as calculated with Friedman and OFW methods for PBSu (1, 2), PBSu/SiO2 1wt% (3,4) and PBSu/SiO2 5wt% (5,6) nanocomposited

Figure 1. Mass loss (%) versus temperature with heating rate ‚=10 oC/min for all the studied samples. 1: PBSu, 2: PBSu+ 0.5 wt% SiO2, 3: PBSu+ 1 wt% SiO2, 4: PBSu+ 2.5 wt% SiO2, 5: PBSu+ 5 wt% SiO2

For the determination of the conversion function f(·) a model fitting method is used. The decomposition of PBSu can be attributed to two mechanisms. When more than one set of data from different heating rates are used, the reaction models Fn and Cn give an almost accepted fit. Only small divergences can be followed for a small first area of mass loss and especially for the lower heating rate. In order to improve the quality of the fitting, mainly for PBSu nanocomposites two reaction mechanisms must be used. The first one is taking place at low mass loss while the second one at higher conversions. In PBSu nanocomposites, combinations i) Cn-Cn, ii) Fn-Cn and iii) Fn-Bna gave essentially the same identification.

DETECTION AND ANALYSIS OF LOW-FREQUENCY ELECTROACOUSTIC SIGNALS IN ELECTROLYTES N. Zografov, N. Tankovsky, M. Vankov University of Sofia, Faculty of Physics, Blvd. James Bourchier 5, Sofia-1164, Bulgaria ABSTRACT A new experimental method is developed, based on the detection of electroacoustic signals, generated by the electrostatic forces at the interface of a polarizable, mobile electrode immersed in electrolyte solution. The electrolytic cell is cylindrically shaped with two parallel plate electrodes, about 8 mm apart, to minimize direct inter-electrode interactions. A massive aluminum electrode is electrically isolated by electrochemically deposited Al2O3 layer, and a mobile thin-foil electrode is fixed over a stretched latex membrane, providing both freedom of displacement and electrical isolation from the electrolyte. The displacements of the mobile electrode, driven by external ac electric field, produce small variations of the pressure in the solution, detected by a piezo-resistive sensor. A dc voltage is applied additionally to polarize the electrodes, separating the anions and cations, which allows one to examine their contribution to the signal separately. The frequency dependence of the obtained signals reveals some characteristic resonances, which have been analyzed in relation with ion content and ion dynamics of the electrolyte solution. Electroacoustic spectra, obtained in simple electrolytes, KCl, LiI and KH2PO4, in the low frequency range (10-1000Hz), have been compared and analyzed.

ANGULAR SYMMETRIC CIRCULAR SONIC CRYSTAL LENSES FOR ACOUSTIC WAVE FOCUSING O.A. Kaya 1 , A. Çiçek 2* and B. Ulu ñ2 1-

Dept. of Computer Education Technologies, Faculty of Education, Inönü University, 44280, Malatya/Turkey 2- Dept. of Physics, F. of Arts & Sciences, Akdeniz University, Campus 07058, Antalya/Turkey *[email protected] ABSTRACT Focusing and imaging properties of a modified hexagonal sonic crystal in which each column of corresponding planar structure lies on concentric arcs is investigated by means of Finite Difference Time Domain simulations. Steady-state solutions for sound pressure level are obtained using Finite Element Method. Focusing and imaging properties of the proposed lens named angular symmetric circular sonic crystal (ASCSC) lens due to its design, are compared with those of its planar counterpart and found to exhibit superior focusing and imaging properties. Wavelength-order confinement of the incident plane-wave around the focal point of ASCSC lens are achieved both in lateral and transverse directions. Dependence of focal length and spot size to the minimum radius of curvature of ASCSC lens reveals that no significant correlation exists between such parameters obeying a formulation, such as the lensmaker’s formula. ASCSC lens is found to display negative dispersion so that waves with longer wavelengths are focused closer. Finite Element Method results indicate existence of several frequency bands in which effective focusing is achieved for each minimum radius of curvature. These bands become broader and closer as the minimum radius of curvature of ASCSC lens increases. The proposed structure has various implementations, such as ultrasonic imaging in medical sciences due to their large numerical aperture, independence of the incidence angle, large confinement factor, small side lobes and observation of a sharp peak at the focal point. 171

MAGNETIC AND TRANSPORT PROPERTIES OF Co/Cu/Ni JUNCTION P. Vlaic University of Medicine and Pharmacy “Iuliu Hatieganu” Physics and Biophysics Department, 400023 ClujNapoca, Romania ABSTRACT Ferromagnetic/Non-Ferromagnetic/Ferromagnetic (FM/NM/FM) trilayer structures are basic elements in any application taking advantage of the giant magnetoresistance effect (GMR). Beside symmetric FM/NM/FM structures, a challenging prototype system is represented by the trilayer configuration consisting of two different magnetic slabs separated by a non-magnetic metallic spacer (FM1/NM/FM2). In the present work the electronic structures of fcc Co/Cu/Ni (001) trilayer systems are studied by means of a selfconsistent principal layer Green’s function technique based on the tight-binding linear muffin-tin orbital method (TBLMTO) in the atomic sphere approximation (ASA) in conjunction with the coherent potential approximation (CPA) in order to describe the interdiffusion at the Co(Ni)/Cu interfaces [1]. Layer decomposed charge transfer and magnetic profile of 5Co/5Cu/5Ni system are presented in Fig. 1. A charge transfer as well as the formation of a small dipole layer with a short spatial distribution is evidenced at the Co/Cu interface. The magnetic moment of interface Co atoms remains comparable with the corresponding bulk value while the Ni magnetic moment is reduced, in agreement with previous data reported for Co/Cu/Co, Ni/Cu/Ni and respectively Co/Cu/Ni systems [2, 3]. Different magnetic behavior of interface Co and Ni atoms is explained in terms of a competition effect between narrowing the density of states (DOS) at Fermi level due to the low coordination number at interfaces and respectively, the hybridization between Co(Ni) and Cu states. Transport properties in the current-perpendicular-to-plane geometry (CPP) have been studied by means of the transmission matrix formulation of the Kubo-Landauer formalism [4]. In either anti- or ferromagnetic states the main contribution to the conductance is given by the majority-spin electrons whose contribution to the transmission amplitude is higher due to the difference in the electronic structure at the Co(Ni)/Cu interfaces. Oscillations of GMR ratio with increasing Cu spacer thickness are observed (Fig. 2). They originate mainly from the oscillation of minority-spin conductance in the FM state.

Fig.1 Layer decomposed charge transfer and magnetic profile for 5Co/5Cu/5Ni system

Fig.2 GMR ratio for some Co/Cu/Ni systems

References [1] I. Turek, V. Drchal, J. Kudrnovsky, M. Sob, and P. Weinberger in Electronic Structure of Disordered Alloys, Surfaces and Interfaces (Kluwer Academic Publishers, 1997). [2] P. Vlaic, M. Alouani, H. Dreyssé, O. Bengone, I. Turek, J. Appl. Phys. 96 (2004) 4352. [3] E. I. Isaev, L. V. Pourovskii, A. M. N. Niklasson, Yu. Kh. Vekliov, B. Johansson and I. A. Abrikosov, Phys. Rev B 65 (2001) 024435 [4] J. Kudrnovsky, V. Drchal, C. Blaas, P. Weinberger, I. Turek, and P. Bruno, Phys. Rev. B 62 (2000) 15084.

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PHOTOELECTROCHEMICAL CHARACTERIZATION OF POLYCRYSTALLINE CdSe, CdTe, AND CuInSe 2 SEMICONDUCTOR FILMS R. Koutsikou*, M. Bouroushian General Chemistry Laboratory, School of Chemical Engineering, National Technical University of Athens, Greece. *[email protected] Semiconductors of the II-VI family such as CdSe, and CdTe, as well as the isovalent I-III-VI compound CuInSe2 are quite attractive for thin film solar cell applications as having direct energy band gaps (ca. 1.7, 1.5 and 1 eV, respectively) and consequently high absorption coefficients. In this work, the use of photoelectrochemical techniques of general applicability in determining useful parameters of the optical and electronic behaviour of these semiconductors is demonstrated. Polycrystalline thin films (1-2 Ìm thick) of CdSe, CdTe, and CuInSe2 were electroplated at constant potential from acid aqueous solutions of the metal salts and selenite or tellurite, on suitably prepared Ti or Ni substrates. Photoelectrochemical cells with different red-ox electrolytes in either two-electrode or three-electrode configuration were used to characterize the as-prepared semiconductors. In particular, flat band potentials were estimated by the photocurrent onset method, by means of linear sweep voltammetry under illumination by a 250W tungsten-halogen (ELC) lamp of controllable intensity (Vis–IR spectral continuum with a color temperature 2700K), and optical band gap widths were measured from the absorption limit of photocurrentspectroscopy curves recorded in a two-electrode (Pt counter) micro-cell, illuminated through a Carl-Zeiss monochromator by a 150 W discharge metal-halides source (color temperature 4200 K). The theory underlying the measuring procedure as well as corrosion-related aspects of the semiconductor electrodes in the photoelectrochemical environment are discussed.

ARCHAEOMETALLURGICAL CHARACTERISATION OF SOME ANCIENT COPPER AND BRONZ ARTEFACTS FROM ALBANIA T. Dilo * 1 N. Civici 2, F. Stamati

3,

O.Cakaj 1

Department of Physics, Faculty of Natural Sciences, University of Tirana, Bul. Zogu I, Tirana, Albania, [email protected] 2 Centre of Applied Nuclear Physics, Faculty of Natural Sciences, University of Tirana, P.O.Box 85, Tirana, Albania, 3 Institute of Folk Culture, Centre of Albanological Studies, Tirana, Albania ABSTRACT 1

Ancient copper and bronz artefacts from different Albanian territories have been analyzed by X-ray-fluorescence analysis to determine the type of alloy and elemental composition. Three bronz coins from Dyrrahu, dating to the IIIrd –IInd century B.C, are composed from copper-tin-lead. A nail exavated at Dyrrahu, dating to IVrth –IIIrd century B.C, is composed from copper. Also, another nail dating to VIth –IVrth century B.C exavated inside an amphora in a ancient ship at Saranda, is composed from copper. The microstructure of those ancient objects is performed using light metallographic microscope to identify how they are made.

RAMAN-BASED EVIDENCE FOR THE PRECIPITATION OF ELEMENTAL SELENIUM OR TELLURIUM AS AN ALTERNATIVE TO FORMATION OF CdS 1–x Se x OR CdSe 1–x Tex NANOCRYSTALS IN BOROSILICATE GLASS Yu.M.Azhniuk 1, A.V.Gomonnai 1, Yu.I.Hutych 1, V.V.Lopushansky 1, M.V.Prymak 1, D.R.T.Zahn 2 1 Institute

of Electron Physics, Ukr. Nat. Acad. Sci., Universytetska Str. 21, Uzhhorod 88017, Ukraine University of Technology, Semiconductor Physics, Reichenhainer Str. 70, D-09107 Chemnitz, Germany

2 Chemnitz

ABSTRACT Diffusion-limited growth is a well-elaborated technique to obtain II-VI semiconductor nanocrystals dispersed in a borosilicate glass matrix. The obtained nanocrystal size is known to depend on the growth conditions (heat treatment temperature and duration). In the case of ternary II-VI nanocrystals, the heat treatment parameters can also somewhat affect the nanocrystal composition. Here we present Raman-based evidence for an alternative process, precipitation of elemental selenium or tellurium in the glass matrix, which is also possible at certain growth conditions. 173

CdS1–xSex and CdSe 1–xTex nanocrystals in borosilicate glass were obtained from commercially available semiconductordoped glasses by a two-step heat treatment procedure – annealing at 1000∞C for 1 h resulting in the glass decolouring (dissolution of the existing nanocrystals) and a subsequent heat treatment at lower temperatures (620–700∞C, 2–12 h). The size and chemical composition of the nanocrystals obtained were determined by optical absorption and Raman scattering spectroscopy. Optical absorption spectra were measured using a LOMO MDR-23 monochromator. Raman measurements were carried out using a Dilor XY800 spectrometer, the excitation was provided by an Ar+ (488.0 and 514.5 nm) or a Kr+ (647.1 and 676.4 nm) laser. All measurements were performed at room temperature. In the Raman spectra of the glass-embedded CdS1–xSex and CdSe 1–xTex nanocrystals, which are characterized by a twomode compositional behaviour, LO1 and LO2 phonon bands, corresponding to the two sublattices of the mixed nanocrystals, are observed. Their frequencies enable the nanocrystal composition to be determined. Meanwhile, for the samples with selenium-rich CdS1–xSex (x>0.75) and CdSe1–xTex (x1). This suggests the presence of a surface diffusion-controlled mechanism, which is confirmed by the experimental data. Contrary to experimental data, simulations lead to the conclusion that the stage which determines the rate of precipitation is that of crystal growth. This means that the precipitation process is associated with nucleus agglomeration.

CONFORMATIONAL TRANSITION IN ELASTIN POLYPEPTIDE WITH DIFFERENT RESIDUE LENGTH Mustafa Bilsel, Handan Arkin Department of Physics Engineering, Ankara University, Dögol Caddesi 06100 Tando ñan, Ankara, Turkey ABSTRACT Elastin-like poly peptides (ELPs) are a family of polypeptides derived from a portion of the primary sequence of elastin, VPGXG, where V:valine, P:proline, G:glycine, and X: any aminoacid except proline. Several ELPs and their derivatives have been used for a number of applications, including drug delivery, protein purification, and tissue engineering. For example, Chilkoti and co-workers have evaluated temperature-responsive ELPs for potential applications in cancer therapy [1,2]. VPGVG is the most abundant repeating peptide in elastin. The most abundant repeating elastin-like sequence Val-Pro-Gly-Val-Gly with different residue lengths are simulated in different aqeous solutions by using multicanonical algorithm[3,4]. In our work, the physical basis of elastin’ s conformational properties and mostly associated physical terms; transition temperature, total energy, heat capacity, radius of gyration and end-to-end distance are investigated. Variation of thermodynamical parameters with respect to temperature have been calculated. On the other hand, Ramachandran plots which provide the distributions of the dihedral angles and allow to distinguish different types of secondary structures have been prepared. As a result, strong dependency of the thermodynamical quantities on both residue number and the details of aqeous solution have been observed.

MATRIX OF EVOLUTION FOR NON-DISSIPATIVE AND TACHYON-LIKE PROCESSES Goran S. Djordjevic Department of Physics, University of Nis, P.O.Box 224, Nis, Serbia ABSTRACT We consider some new and general properties of quantum mechanics, defined on local and nonlocal spaces. In particular, we discuss a connection between classical and quantum dynamics on real and generalized – adelic spaces. This approach has been motivated by the hypothesis of non-archimedean, and nonlocal, nature of space-time at the very short distances. Adelic quantum mechanics has been successfully applied in quantum cosmology and we discuss it in the frame of an inflationary scenario. In particular, connection between elements of the classical evolution matrix for the exactly solvable systems and the conditions of adelicity is presented. We extend our earlier developed method, which has been valid for a class of autonomous and nonautonomous systems, and compare similarities and differences between non-dissipative and dissipative processes.

185

NUMERICAL SIMULATION ON DELAYED COALESCENCE OF DROPLETS IN CONFINED GEOMETRIES Rodica Borcia and Michael Bestehorn Department of Statistical Physics and Nonlinear Dynamics Brandenburg University of Technology, Erich-Weinert-Str. 1, 03046-Cottbus, GERMANY Email: [email protected] ABSTRACT We report on computer simulations for coalescence of droplets with perfectly miscible liquids. This application is motivated by recent experimental observations showing that sessile droplets of completely miscible liquids do not instantaneously coalesce after their lateral contact if their contact angles are sufficiently small. Instead, a microscopically thin liquid bridge connects the droplets and delays the droplet fusion. The drops exchange liquid through this film, but they remain separated. After some time (up to minutes) the droplets finally merge into a single droplet and the fluid comes to rest [1]. The coalescence dynamics is obviously influenced by surface forces and qualitatively depends on the contact angles. The theoretical framework is based on a phase field model previously developed for sessile drops in a vapor atmosphere on a horizontal solid substrate [2]. In the present paper one needs two order parameters: one characterizes the phase of the system (liquid or vapor state), and the second one characterizes the relative liquid composition (liquid 1 or liquid 2). The drops dynamics is described by the Navier-Stokes equation with extra phase field terms (including the contribution of capillary forces at the droplets interface) and the continuity equations for the mass and concentration field. 2D numerical simulations are performed for closed systems (confined geometries) with different ratios between the surface and viscous forces. Depending on this ratio, different behaviors of delayed coalescence are observed from “chasing droplets” to “droplets repulsion”.

FIG 1: Time evolution of non-temporary coalescence of two drops consisting of different perfectly miscible liquids [1] H. Riegler, P. Lazar, Langmuir 24, 6395 (2008) [2] R. Borcia, I.D. Borcia, M. Bestehorn, Phys. Rev. E 78, 066307 (2008)

THEORETICAL CALCULATIONS OF EXCHANGE AND ANISOTROPY OF TCNE-BASED ROOM-TEMPERATURE MOLECULAR MAGNETS Fanica Cimpoesu 1 , Bogdan Frecu {2, Corneliu I. Oprea 2, and Mihai A. Gîr †u 2* 1 Institute 2Department

of Physical-Chemistry, Splaiul Independen †ei 202, Bucharest 060021, Romania of Physics, Ovidius University of Constan †a, Bd. Mamaia 124, Constan †a 900527, Romania

ABSTRACT We report here quantum chemical calculations providing the optimized geometry, the electronic structure, the Heisenberg exchange coupling constant, and the magnetic single-ion anisotropy of the M[TCNE]2 family of molecular magnets (TCNE = tetracyanoethylene, M = V, Mn). The M[TCNE]x y(solvent) family (M = V, Fe, Mn, Ni, Co, whereas solvent = dichloromethane, acetonitrile, tetrahydrofuran) has been one of the most extensively studied due to the large critical temperature of these compounds. For instance, V[TCNE]xy(CH2Cl2) is the first room-temperature molecular 186

magnet and the only one with an active organic component (with a net spin on TCNE). Despite detailed magnetic, spectroscopic and conductivity studies the mechanism for the strong exchange coupling in the family M[TCNE]x y(solvent) has remained an open question, the difficulty being related to the absence of structural data for these amorphous compounds. Starting from a new structural model that we propose for these systems we report the results of Density Functional Theory (DFT) calculations providing the optimized geometry of a periodic lattice. Based on these results we further discuss the possible origin of the structural disorder leading to the various degrees of amorphousness of the powders synthesized chemically or the films obtained by physical vapor deposition. With a combination of DFT and multiconfiguration ab initio methods we further explore the major common magnetostructural feature of a wide variety of TCNE-based species, such as the series of Mn(porphyrin)-TCNE or the M[TCNE] xy(solvent) materials, which is the strong antiferomagnetic coupling between the metal ion and the radical anion TCNE.- ligand and the long range magnetic ordering determined by it. The exchange coupling is sensitive to the coordination geometry and the electronic configuration of the metal ion (J/kB of about 300 K for M = V and less than 100 K for M = Mn), in good agreement with the experimental data. Another important feature, also strongly dependent upon the configuration and coordination effect is the magnetic anisotropy, also rationalized within the frame of the magnetostructural correlations presented. References: J. M. Manriquez, G. T. Yee, R. S. Mclean, A. J. Epstein and J. S. Miller, Science 252, 1415 (1991); C. M. Wynn, M. A. Gîr_u, J. Zhang, Joel S. Miller, A. J. Epstein, Phys. Rev. B 58, 8508 (1998); M. A. Gîr_u, C. M. Wynn, J. Zhang, Joel S. Miller, A. J. Epstein, Phys. Rev. B 61, 492 (2000); C.I. Oprea, A. Damian, M.A. Gîr_u, AIPConference Proceedings 899,. 716 (2007); F. Cimpoesu, B. Frecu_, C.I. Oprea, M.A. Gîr_u, to be published. Funded by CNCSIS, the Romanian National University Research Council, grant PN2-Idei number 174/2007. *E-mail: [email protected]

NONLINEAR TIME-SERIES ANALYSIS METHODS FOR THE EVALUATION AND STUDY OF DYNAMICAL PHENOMENA IN ATOMIC FORCE MICROSCOPY Prediction of chaotic motion Georgakaki D. 1, Mitsas Ch. 2, Polatoglou H.M. 1Physics 2Laboratory

1

Department, Solid State Physics Section, AUTH., 54124 of Mechanical Measurements, ∂.π.ª., Thessaloniki, 57022

ABSTRACT Atomic Force Microscopy (AFM) is a widely used tool for nanoscale surface analysis. Basic AFM operational modes measure the topography of a sample as well as its electrical, mechanical, and chemical properties. In a typical AFM system there exist three different open-loop modes: i) contact mode, ii) tapping or intermittent mode and iii) non-contact mode. Dynamic atomic force microscopy (tapping or non-contact mode) consists of a vibrating microcantilever with a nanoscale tip that interacts with a sample surface via short - and long-range intermolecular forces. Due to the need of high precision measurements, the interaction forces between the nanotip and the specimen must be carefully examined and analyzed in order to best evaluate the nonlinear dynamical response of the AFM system. Though widely practiced, the dynamic AFM modes exhibit the potential for unwanted dynamic phenomena such as phase jumps, period doublings or even chaotic behavior in the cantilever tip displacement, thus rendering erroneous topographical information and causing instabilities that reduce the quality of the image. As a result, recent research on AFM systems has focused on detailed numerical analysis such that this chaotic behavior region can be well defined and ideally avoided. In this paper, nonlinear time-series analysis methods (TSA) are applied to analyze signals generated by a numerical single-degree-of-freedom lumped-model of a tapping-mode AFM. The signal characteristics will provide useful insight of the nonlinear system response leading to the evaluation of deterministic uncertainty in real-time AFM measurements that is being introduced because of these phenomena. The confirmation of chaos existence and the prediction of the regions where chaotic motion is possible remain crucial for the quality of AFM images. The methods used for the system analysis include the Autocorrelation Function, the Power Spectral Density Analysis, the Poincare Maps, the Liapunov Exponents and the estimation of the Embedding Dimension. Last two methods are very crucial for the prediction of chaotic regimes that can add unwanted noise in AFM images. All the above computational techniques can then be applied to experimental AFM data in order to find system parameters and regimes, which ensure stable motions across the sample surface scanning process. 187

SIMULATION OF PATTERN MORPHOLOGY IN BINARY LIQUID MIXTURES Ion Dan Borcia and Michael Bestehorn Brandenburg University of Technology, Department of Theoretical Physics II Erich-Weinert-Strasse 1, 03046-Cottbus, Germany E-mail: [email protected] ABSTRACT We performed simulations using a model based on long wave approximation [1] for the case of liquid thin layer consisting on binary mixtures. The surface tension depends on both temperature and concentration. The pattern morphology is investigated for the cases of monotonic (Fig. 1) and oscillatory instabilities. Contrary to the simplified model [2] one considers convective terms and vertical variation of temperature and concentration. The liquid velocity of the mixture is assumed to be a quadratic function of the liquid height. Other numerical methods involving time-depending boundaries imply the calculation of the integration grid using spline algorithms (boundary-fitted coordinate solving method [1]). In our case the film height h(x,y,t) gives directly the integration grid for the 3D concentration equation. Firstly, the case of periodic lateral boundary conditions is studied. Then the influence of rigid, no-flux boundary conditions on pattern morphology is investigated.

Fig. 1 Time series for the evolution of a binary mixture in the case of monotonic instability [1] Oron A., Davis S.H., Bankoff S.G., Long-scale evolution of thin liquid films, Rev. Mod. Phys., Vol. 69 pp 931-980 (1997). [2] Borcia I.D., Borcia R., Bestehorn M., Soret effect in thin liquid films: Localized running drops, holes and stripes, Eur. Phys. Lett., Vol. 75 pp. 112-118 (2006). [3] J.F. Thompson et al., Boundary-fitted coordinate systems for numerical solution of partial differential equations – a review, J. Comput. Phys. Vol. 47 pp.1-108 (1982).

GENERALIZED EVOLUTIONARY EQUATIONS WITH IMPOSED SYMMETRIES R. Constantinescu, R. Cimpoiasu Abstract: The paper intends to propose an algorithm which could identify a general class of pdes describing dynamical systems with similar symmetries. The way that will be followed starts from a given group of symmetries, the determination of the invariants and, then, of the compatible equations of evolution. The algorithm will be exemplified with an equation generalizing the Fokker-Planck evolutionary process.

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BOUNDED COULOMB POTENTIAL E. Ateser * and H. Ciftci

**

* Aksaray University (ASÜ) Faculty of Science and Arts Physics department, Aksaray/Turkey **Gazi University Faculty of Science and Arts Physics department, Teknikokullar, Ankara/Turkey ABSTRACT In this work, we have studied a bounded Coulomb Potential which may be used to explain quarkonium. For this potential, energy Eigen values of Schrödinger equation have been calculated by the Asymptotic Iteration Method AIM).

EVOLUTION OF ENTANGLEMENT IN OPEN QUANTUM SYSTEMS GENERATION AND SUDDEN DEATH OF ENTANGLEMENT FOR A TWO-OSCILLATOR SYSTEM IN A THERMAL BATH Aurelian Isar Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania ABSTRACT The physics of quantum entangled states, an interdisciplinary field of research involving quantum optics, physics of quantum information and foundations of quantum theory, has been intensively exploited over the last years in connection with quantum information processing, quantum communication and quantum computing. The use of entangled states opens new horizons in such practical fields like cryptography, computing, information transmission, quantum imaging and precision measurements. Essential progress has also been achieved in the area of photon squeezing, generation of nonclassical states, including Schrödinger cats, trapped ions, Bose–Einstein condensates, cavity quantum electrodynamics, Casimir effect. In the framework of the theory of open systems based on completely positive quantum dynamical semigroups [1,2], we study the continuous variable entanglement for a system consisting of two independent harmonic oscillators interacting with a general environment. We solve the Markovian master equation for the time evolution of the considered system and, by using Peres–Simon necessary and sufficient criterion for separability of two-mode Gaussian states [3,4], we describe the generation and evolution of entanglement in terms of the covariance matrix, for a Gaussian initial state. We show that for certain values of diffusion and dissipation coefficients describing the environment, the state keeps for all times its initial type: separable or entangled. In other cases, entanglement generation, entanglement sudden death or a periodic collapse and revival of entanglement take place [5]. In particular, we describe the dynamics of entanglement in terms of the squeezing coefficient of the initial Gaussian state and the temperature of the thermal bath. We analyze also the time evolution of the logarithmic negativity, which characterizes the degree of entanglement of the quantum state [6]. [1] G. Lindblad, Commun. Math. Phys. 48, 119 (1976) [2] A. Isar, A. Sandulescu, H. Scutaru, E. Stefanescu, W. Scheid, Int. J. Mod. Phys. E 3, 635 (1994) [3] A. Peres, Phys. Rev. Lett. 77, 1413 (1996) [4] R. Simon, Phys. Rev. Lett. 84, 2726 (2000) [5] A. Isar, Int. J. Quantum Information 6, 689 (2008) [6] A. Isar, Open Sys. Information Dyn. 16, No. 2-3 (2009)

COHOMOLOGY METHODS IN CAUSAL PERTURBATION THEORY Dan Radu GRIGORE Dept. Theoretical Physics, Institute for Physics and Nuclear Engineering “Horia Hulubei” ABSTRACT Various problems in perturbation theory of (quantum) gauge models can be rephrased in the language of cohomology theory. This was already noticed in the functional formulation of perturbative gauge theories. Causal perturbation theory is a fully quantum approach: is works only with the chronological products which are defined as operator-valued distributions in the Fock space of the model. The use of causal perturbation theory leads to similar cohomology problems; the main difference with respect to the functional methods comes from the fact that the gauge transformation of the causal approach is, essentially, the linear part of the non-linear BRST transformation. 189

Using these methods it is possible to give a nice determination of the interaction Lagrangians for gauge models (YangMills and gravitation in the linear approximation); one obtains with tis method the unicity of the interaction Lagrangian up to trivial terms. The case of quantum gravity is highly non-trivial and can be generalized with this method to the massive graviton case. Going to higher orders of perturbation theory one finds quantum anomalies. Again the cohomological methods can be used to determine the generic form of these anomalies. Finally, one can investigate the arbitrariness of the chronological products in higher orders and reduce this problem to cohomology methods also.

ORTOGONAL POLYNOMIAL FITTING METHOD APPLIED TO CONTACT ANGLE DATA VARIATIONS Nina Bogdanova, Stefan Todorov Institute of Nuclear Research & Nuclear Energy, BAS, Bulgaria Email: [email protected], [email protected] ABSTRACT We discuss our method of constructing orthogonal polynomials (orthonormal polynomial expansion method -OPEM) for fitting experimental data. The method is in use to fit a set of data of a dependent variable if both the dependent and independent variables are measured with errors. We review its main principles and analyze the stability of the coefficients of the approximating polynomial with respect of small perturbations of the data. The fitting method is applied to the variations of the wetting angle of a liquid drop. It is situated on the substrate in the process of its evaporation in the air. The wet ability properties of liquids are at present a high interest for research due to applications to still unsolved topics in the theory of wetting . References: 1. Bogdanova N., Todorov St., IJMPC, 12, No.1(2001 )pp.117-127. 2. Bonn D., D. Ross, Wetting transitions, Rep. Progr. Phys. ,64 (2001) 1085.

MATHEMATICAL DESCRIPTION OF ADDITIONAL LOW TEMPERATURE COMPONENTS OF THE SPECIFIC HEAT FOR TWO FLUOROPOLYMERS, PTFE AND PCTFE Nina Bogdanova 1 and Bonka Terziyska 1

2

Institute of Nuclear Research and Nuclear Energy, Email: [email protected] 2 Institute of Solid State Physics, Email: [email protected]

ABSTRACT Our orthonormal polynomial expansion method (OPEM) is used here for describing the additional low temperature specific heat components of Polytetrafluoroethylen (PTFE) and Polychlorotrifluoroethylene (PCTFE). The temperature dependencies of the excess specific heat for the both semi-crystalline polymers are described mathematically up to 7-8 K in the present work. The peculiarity established earlier in Cp/T3 vs. T of the PTFE and PCTFE manifested by a maximum appearing around 5 K for both fluoroplasts is hardly to be explained with the Debye model. This hump analyzed in our previous work was related to the additional low-frequency vibration modes (soft modes), localized together with lattice vibrations (sound waves) as it is postulated in the Soft Potential Model (SPM). The estimated excess specific heat data and approximating curves determined by the usual polynomial coefficients obtained by orthonormal ones in our OPEM approach, are presented too. References: 1. Terziyska B., H.Madge, Some special features of the low-temperature specific heat of PTFE and PCTFE analyzed within the SPM, to be published. 2. Bogdanova N., Terziyska B. , http://arXiv.org e-Print archive, E-print No.0811.1683v[physics.comp-ph],2008.

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ANALYTICAL EVALUATION OF BOYS INTEGRAL Mehmet Kara 1 , Ay{e Nalçaci 2, Telhat Özdo ñan 2* 1Department

of Physics, Faculty of Arts and Sciences, Abant Izzet Baysal University, Bolu-TURKEY of Physics, Faculty of Arts and Sciences, Rize University, Rize-TURKEY *e-mail: [email protected]

2Department

ABSTRACT An analytical procedure have been presented for the evaluation of Boys integrals by dividing the integral region [0,1] into several parts. The obtained formula includes well-known binomial coefficients and a well known auxiliary function that converges very well. A computer program has been constructed in Maple symbolic programming language for comparing our results with literature. It is seen that the procedure we presented agree well with the numerical results obtained by Maple and available literature.

A MAPLE PACKAGE FOR ENERGY – MOMENTUM TENSOR ASSESSMENT IN CURVED SPACE - TIME Gabriel MURARIU 1

1

Faculty of Sciences, Physics Department, University “Dun

årea de Jos” Gala †i, Romania

ABSTRACT One of the most interesting problems which remains unsolved, since the birth of General Theory of Relativity (GR), is the energy-momentum localization. All our considerations are within the Lagrange formalism of field theory. The concept of the energy-momentum tensor for gravitational interactions has a long history. To find a generally accepted expression, there have been different attempts. This paper is devoted to the investigation of the energy-momentum problem in the General Relativity theory. We use Einstein [1], Landau-Lifshitz [2], Bergmann-Thomson [3] and Moller’s [4] prescriptions to evaluate energy-momentum distribution. In order to cover the huge volume of computation and, bearing in mind to make a general approaching for different space-time configurations, was built a MAPLE application to succeed in studying the energy momentum tensor. In the second part of the paper were presented for two space-time configuration, the comparative results. Reference: [1]. M. Sharif , Kanwal Nazir, , arXiv:0801.1882v1 [2]. C. Dariescu, M. Dariescu, Phys.Lett.B566:19-26,2003 [3] S.V. Babak, L.P. Grishchuk, arXiv:gr-qc/9907027v2 [4] Walter Wyss, arXiv:math-ph/9912022v1. [5] M.A. Dariescu, C. Dariescu Phys.Lett.B548:24-28,2002. [6] M. Visinescu, Killing-Yano tensors on manifolds admitting ‘hidden’ symmetries.- Prepared for International Symposium on Advances in Nuclear Physics, Bucharest, Romania, 9-10 Dec 1999. [7] C. Dariescu M. Dariescu, , Ph. Letters B, (2003), 566 [8] C. Dariescu, M. Aura Dariescu, I. Gottlieb , Teoria cuantic_ a câmpului, Ia_i, (2000) [9] Ion I. Cotaescu e-Print: arXiv:0708.0734 [gr-qc]

DFT STUDY OF OPTICAL PROPERTIES OF Pt-BASED COMPLEXES Corneliu I. Oprea 1, Anca Dumbrav ø1, Florin Moscalu, 1Ovidius

1

Athanassios Nicolaides

2,

and Mihai A. Gîr †u 1*

University of Constan †a, Bd. Mamaia 124, Constan øa 900527, Romania of Chemistry, University of Cyprus, Nicosia 1678, Cyprus

2Department

ABSTRACT We report Density Functional Theory (DFT) calculations providing the geometrical and electronic structures, as well as the optical properties of the homologous series of pyramidalized olefins [(CH2)n-(C8H10)-Pt-L2]2+ and [(CH 2)n-(C8H10)-PtL’2]2+, where L=PPh3, L’=PH3 and n=0,1,2,3. In these compounds, the lowest unoccupied molecular orbital depends strongly on the number n of methylene groups in the bridge of olefin, which allows for the fine-tuning of their optical 191

properties in a systematic way. All Pt complexes were geometry optimized for the singlet ground state in vacuum using Density Functional Theory with B3LYP exchange-correlation functional and the Effective Core Potential LANL2DZ basis set, within the frame of Gaussian03 quantum chemistry package. We found the coordination geometry of Pt to be distorted square planar. In the case of complexes containing the PPh3 ligands the dihedral angle is about 50o, while for the simpler complexes with PH 3 ligands, the dihedral ranges from 0o to 8 o. Electronic transitions were calculated at the same level of theory by means of TDDFT. In all cases the first absorption band is attributed to HOMO to LUMO transitions. For the large systems, the HOMO is localized on the phenyl rings, while in the case of the PH3 ligands it has strong dz2 character. This important difference leads to larger absorption intensities while using PPh3 instead of PH 3 as ligands. In all cases the LUMO is localized on the olefin. The first band for n=0 peaks at 1.9 eV and the spectra shift towards IR upon increase of number of methyl groups in the bridge of olefin. The relevance of the Pt-based compounds as possible pigments for dyesensitized solar cells is discussed. References: M.K. Nazeeruddin, F. De Angelis, S. Fantacci, A. Selloni, G. Viscardi, P. Liska, S. Ito, B. Takeru, M. Grätzel, J. Am. Chem. Soc . 127, 16835 (2005); D.P. Hagberg, J.-H. Yum, H.J. Lee, F. De Angelis, T. Marinado, K. Martin Karlsson, R. HumphryBaker, L. Sun, A. Hagfeldt, Michael Grätzel, M.K. Nazeeruddin, J. Am. Chem. Soc. 130, 6259 (2008); T.H. Dunning Jr. and P.J. Hay, In Modern Theoretical Chemistry; H.F. Schaefer III, Ed.; Plenum: New York, 1976; Vol. 3; C.I. Oprea, B. Frecus, P. Panait, F. Moscalu, A. Dumbrava, B.F. Minaev and M.A. Gîr_u, to be published. Funded by ANCS, the Romanian Authority for Scientific Research, grant PN2-Capacitati-M3 number 128/2009. *E-mail: [email protected]

FIRST PRINCIPLES STUDY OF ELECTRONIC AND CRYSTALLOGRAPHIC STRUCTURE AND ELASTIC PROPERTIES OF RbNiF 3 V. Antonov* K. Krezhov* N.Trendafilova** *Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia, Bulgaria **Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. Georgi Bonchev, build. 11, 1113 Sofia, Bulgaria ABSTRACT First principles calculations, based on density functional theory (DFT) with ultra-soft pseudo potentials were performed to simulate the electronic, magnetic and crystallographic structure and elastic properties of RbNiF3, a candidate for magneto optical applications. The transparent magnetodielectric RbNiF3 is of interest because in contrast to the majority of other ABF3 compounds which are orthorhombic perovskites it is a representative of a much smaller group of chalcogenides with hexagonal crystal symmetry. In fact, this is the structural phase at normal pressure and it is isomorphous with the hexagonal modification of BaTiO3. The compound becomes ferrimagnetically ordered below a Néel temperature reported o as 135 K. Synthesis at elevated temperature and pressure yields another phase that is a cubic perovskite (a = 4.074 Ao,), reported as antiferromagnetic. Simulations were performed using the generalized gradient approximation exchangecorrelation functional with included Hubbard correction term; (GGA+U) approach. The relative stabilities of the hexagonal and cubic phases versus applied pressure were investigated. The stability of different magnetic structures available from theoretical calculations and experimental results has been studied. Via the constrained magnetization technique the exchange integrals have been calculated. The elastic constants have been evaluated via the Birch-Murnaghan equation of state. According to the DFT calculations RbNiF3 is an insulator in both phase structures. The present results for calculated electronic band structure, magnetic structures, lattice parameters, atomic positions and elastic constants can reproduce reasonably well the available own and literature data. An alternative metastable magnetic structure with reduced symmetry of RbNiF3 in hexagonal crystal structure was predicted. For the cubic phase G type antiferromagnetic ordering with magnetization collinear to axis was predicted.

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FIRST PRINCIPLES STUDY OF ELECTRONIC AND CRYSTALLOGRAPHIC STRUCTURE AND ELASTIC PROPERTIES OF CHROMIUM NITRIDE V. Antonov* and I. Iordanova* *Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria. **Department of Solid State Physics and Microelectronics, Faculty of Physics, University of Sofia, 5 blvd. J. Bouchier, 1164 Sofia, Bulgaria. ABSTRACT Chromium nitride (CrN) has extreme hardness and corrosion resistance. It is applied as thin surface coatings on treated details. For the characterization of the properties of the deposited films the elastic constants of the CrN are required. At room temperature it is paramagnetic and crystallizes in face cantered cubic crystal structure of NaCl type, however below the Neel temperature the structure undergoes orthorhombic distortion and becomes antiferromagnet with fourth type of magnetic ordering. The first principles calculations, based on density functional theory with ultra-soft pseudo potentials were performed to investigate the electronic and crystallographic structure and elastic properties of chromium nitride. Simulations were performed using generalized gradient approximation exchange-correlation functional. Assumed were non-magnetic, ferromagnetic and antiferromagnetic AFM1[110] and AFM2[110] orderings. For the nonmagnetic and ferromagnetic cases the crystallographic structure of CrN remains cubic. For the experimentally observed AFM2[110] structure orthorhombic distortion is evident, while for the AFM1[110] there is a tendency for a small tetragonal distortion from cubic structure. The calculated band and magnetic structures, lattice parameters, atomic postitions and elastic constants were compared with the available experimental and theoretical results. The most stable structure is the experimentally observed at low temperatures AFM2[110], however the results for the elastic constants of AFM1[110] compare well with the experiment.

A 3-DIMENSIONAL MODEL FOR A PHOTOVOLTAIC CELL Romeo NEGREA 1 , Ioan ZAHARIE

2

1 Departament

of Mathematics, “Politehnica” University Timi {oara, Victoriei Place No.2,300006, Timi {oara, Romania 2Departament of Physics, “Politehnica” University Timi {oara, Vasile Pârvan Blvd, No.2, 300223, Timi {oara, Romania contact : 1 [email protected], 2 [email protected], [email protected] ABSTRACT The first approach in modelling the behaviour of the electrons in a photovoltaic cell was a hydrodynamic model. The hydrodynamic model treats the propagation of electrons in a semiconductor as a flow of the electric charge in an electric field. Semiconductor models based on classical or semi-classical mechanics (like drift-diffusion equation, hydrodynamic models and the semi-classical solid state physics Boltzmann equation) cannot be used to reasonable describe the performance of ultra-integrated devices, which are based on quantum effects. In the last years the so-called quantum hydrodynamic model (QHD) has been introduced [1]. The quantum hydrodynamic model has the advantage of dealing with macroscopic fluid-type unknowns and it is able to describe quantum phenomena, such as negative differential resistance in a resonant tunneling diode. Mathematically, the QHD system is a dispersive regularization of the hydrodynamic equations. The starting point of our investigation is the Schrödinger equation for a QHD model which describes the electrons evolution in a semiconductor medium adding the Bohm quantum corrections. The solving of the Schrödinger equation in the above form concerned many mathematicians from different domains: ordinary differential equations, partial differential equations, complex analysis, operator theory, differential geometry, numerical analysis, computational geometry, etc. Different approaches to solve this variant of the Schrödinger equation have been proposed. An elegant and interesting method is based on the Madelung’s transform

193

FISHER INFORMATION AND SHANNON ENTROPY IN CONFINED 1D HARMONIC OSCILLATOR Ljiljana Stevanovi ¶ Department of Physics, Faculty of Sciences and Mathematics, University of Ni ABSTRACT

£, 18000 Ni £, Serbia

Study of the linear harmonic oscillator confined in the square well with impenetrable walls is of great interest since its application for modeling parabolic quantum well semiconductor heterostructures. Fisher information and Shannon entropy, as a complexity measure for its ground and some excited energy levels are reported here.

STATISTICAL APPROACH OF MODULATIONAL INSTABILITY FOR CYLINDRICAL AND SPHERICAL NLS EQUATIONS A. T. GRECU 1 , S. DeNICOLA 2, R. FEDELE 3, D. GRECU 1, A. VISINESCU

1

Department of Theoretical Physics, “Horia Hulubei” National Institute of Physics and Nuclear Engineering, Atomistilor str., 407, RO-077125, Bucharest, Romania 2 Istituto di Cibernetica del C. N. R. “Eduardo Caianiello”, Viale Campi Flegrei, 34, I-80078, Pozzuoli, Italy 3 Dipartimento di Scienze Fisiche, Università Federico II and INFN Sezione di Napoli, Complesso Universitario di M. S. Angelo, Via Cintia, I-80126, Napoli, Italy ABSTRACT 1

The statistical approach of the modulational instability (SAMI) for cylindrical and spherical NLS equations is developed starting from the equation of motion for a two-point correlation function, written in a Gaussian approximation. From a linear stability analysis an integral stability/instability equation is obtained. This is solved for different initial distributions (delta-function, Lorentzian, Gaussian) and the corresponding instability domains are found. Unlike the other NLS equations in these cases the instability regions depend on time.

CONFORMATIONAL AND VIBRATIONAL STUDIES OF TRICLOSAN Semran SA ¤LAM 1, Haci OZI }IK2 and S. Haman BAYARI 3, 1 Gazi

University, Ankara, Turkey, [email protected] University, Aksaray, Turkey, [email protected] 3Hacettepe University, Ankara, Turkey, [email protected] 2Aksaray

ABSTRACT 5-Chloro-2-(20,40-dichlorophenoxy)-phenol (TCS), known as triclosan. It is a potent wide-spectrum antibacterial and antifungal agent. It is found in soaps, deodorants, toothpastes. The biological functions of flexible bio-molecules depend on the conformation that the molecules can adopt. A systematic conformational search for triclosan has been performed by varying dihedral angles as shown in (Fig. 1). The optimized geometries and relative energies of the possible conformers of triclosan have been calculated using density functional theory (DFT/ B3LYP/6-311++G(d,p)) method. The quantum chemical calculations were carried out within the Gaussian 03 program on the Workstation at the Gazi University. The IR spectrum of triclosan was measured in the 4000-400 cm-1 region. We calculated the harmonic frequencies and intensities of the most stable conformers in order to assist in the assignment of the vibrational bands in the experimental spectrum. The fundamental vibrational modes were characterised depending on their total energy distribution (TED%) using scaled quantum mechanical (SQM) force field method. The calculated vibrational spectra were interpreted and band assignments were reported.

194

Figure 1. Triscolan molecule and scanned dihedral angels for conformational analysis.

SYMMETRY OF REFERENCE, BASE TO GENERAL LORENTZ TRANSFORMATIONS M. Petre, M. Dima, C. Petre National Institute for Nuclear Physics and Engineering, P.O.Box MG-6, RO-077125 Bucharest-Magurele, Romania, E-mail: [email protected] ABSTRACT Starting with the 1905 paper [1] of A. Einstein in Ann. Phys. the Lorentz Transformation has been traditionally derived based on the Principle of Relativity and light-speed universality. Various studies [2] have shown that light-speed universality is not needed - the first such publication (1906) being owed to H. Poincar_e [3]. Group theory expresses the transitivity property of relativity (C relative to A, if A to B and B to C) in the form of the group closure relation, respectively the product of two group elements being another element of the group. Pure relativity transformations however, cannot form a group on their own, needing rotations to "close" the group. Therefore it is not possible - without more information, to specify the group to which relativity transformations belong to, meaning that the full group is not immediate just from the Principle of Relativity. Traditionally the transformations were specified as belonging to a group that invaries the metric, LÖGL = G, where L are the transformations and G the metric. This however is an over-specification of the physical problem, exceeding the Principle of Relativity. Further more, entering the Lorentz group - i.e. specifying a particular metric (in this case Mikowsky), is equivalent in the end with admitting light speed invariance. In this sense the Principle of Relativity and (indirectly) light speed invariance are core to the Lorentz Transformation [4]. The present contribution shows however, that neither statement is necessary and that the Lorentz transformation stems from the simpler (weaker) Principle of Symmetry of reference systems, respectively defining the transformations with the aid of a group is not needed (less so a particular group, say the Lorentz group). This approach shows that the Minkowsky metric is not unique in defining relativity. It will be shown that in fact there are two possible classes of transformations, one invarying the Minkowsky and the other the Euclidian metric. [1] Einstein, A.: Ann. Phys. 17, 891 (1905) [2] Levy-Leblond, J.M.: Am. J. Phys. 44, 271 (1976) [3] Poincaré, H.: Rend. Circ. Mat. Palermo 21, 129 (1906) [4] Berzi, V., Gorini, V.: J. Math. Phys. 44, 271 (1976)

195

G EDUCATION, HISTORY OF PHYSICS & PHYSICS and ARTS TEACHING ENERGY AS A SINGLE ENTITY OF MULTIPLE FORMS AND CHARACTERISTICSV Despina M. Garyfallidou M.Sc. The Science Laboratory, University or Patras ABSTRACT The present study represents a small part of a much broader project involving the design of a new curriculum approach to teach the energy concept in its entirety. Subsequently, an original piece of educational software was designed and developed to teach the energy concept using this curriculum approach. To test both the new curriculum as well as the educational software, a dual testing technique was followed. The novel curriculum was implemented in class using conventional teaching techniques (103 students). Separately, the new educational software was also tested in a classroom environment (109 students), while all these were compared to a control group of ordinary school leavers (231 students). The data-taking and data-analysis preformed have been extensive. A small part of the final results of this dual educational trial are presented herein, in which some educational observations are also presented, and conclusions reached are briefly discussed.

HIGH SCHOOL CLASS FOR GIFTED PUPILS IN PHYSICS AND SCIENCES AND PUPILS’ SKILLS MEASURED BY STANDARD AND PISA TEST G. S. Djordjevic and D. Pavlovic-Babic *

*

Department of Physics, University of Nis, P.O.Box 224, Nis, Serbia Institute for Psychology, Faculty of Philosophy, Cika Ljubina 18-20, Belgrade, Serbia

ABSTRACT The high school class for students with special abilities in physics was founded in Nis, Serbia (www.pmf.ni.ac.yu/f_odeljenje) in 2003. The basic aim of this project has been introducing of a broadened curriculum of physics, mathematics, computer science, as well as chemistry and biology. Now, six years after establishing of this specialized class, and 3 years after the previous report, we present analyses of the pupils` skills in solving rather problem oriented test, as PISA test, and compare their results with result of pupils who study under standard curricula. More precisely results are compared to the progress results of the pupils in a standard Grammar School and the corresponding classes of the Mathematical Gymnasiums in Nis. Analysis of achievement data should clarify what are benefits of introducing in school system track for gifted students. Additionally, item analysis helps in understanding and improvement of learning strategies’ efficacy. We make some conclusions and remarks, may be useful for the future work that aims to increase pupils` intrinsic and instrumental motivation for physics and sciences, as well as to increase the efficacy of teaching physics and science.

196

THE EUGENIDES FOUNDATION INTERACTIVE EXHIBITION OF SCIENCE AND TECHNOLOGY I. Kontogiannis Eugenides Foundation 387, Syngrou Ave., 175 64 Paleo Faliro, Athend, Greece ABSTRACT In late 2006, Eugenides Foundation opened the Interactive Science and Technology Exhibition, a pioneering site that combines learning and entertainment. It comprises of 65 interactive exhibits grouped in three thematic collections: Matter and Materials, Light and Sound and Biotechnology. It was designed and developed by the ‘‘Cite des Sciences et de l’ Industrie’’ (Paris, France) and is installed in an area of 1200 m2 at the Eugenides Foundation Science Center, (Athens, Greece). The main goal of this interactive exhibition is to stimulate the visitors’ mind and test their knowledge, imagination and resourcefulness. Various extra activities take place inside the exhibition during weekends, such as live science demonstrations, performed by young scientists. Extra material such as short news, science comics, portraits, exhibition guides and treasure-hunting based games, all available online as well, are prepared on a monthly basis and are available to the visitors. Inside the Interactive Science and Technology Exhibition, scientific facts are made simple and easy to comprehend, using modern presentation tools. This paper presents details on how this exhibition can complement the science education at school, thus being a highly valuable educational tool.

SOME LIVE ISSUES OF THE PHYSICS TEACHING IN ALL THE SCHOOL LEVELS Author: Dr. Silvana Mico Co: Dr. Jorgo Mandili Physics Department, Vlora University, Albania Abstract In many countries the levels of social and economic development are also the determinants of education policies. During the last 10 years Albania had new developments in social and economic environment , but the education policies has remain the same or have been almost insignificantly enhanced. It isn’t our intention discussing these policies, but just expressing some considerations according to the most recent experience and our vision. These considerations regard the teaching physics quality in all the school levels. It’s truth that students have serious difficulty in understanding physics. We have tried to understand why and how we can help them? We have investigated how learn physics concepts the students that attending introductory physics course at Vlora University (VU) and the pupils of the some elite secondary schools. Keywords: physics education research (PER), missconceptions, critical reasoning , learner -centered environment , interactive lectures .

TEACHING PHYSICS: UTILIZATION OF SCRATCHBOARD IN LABORATORYIES ACTIVITIES T. Pierratos, E. Koltsakis, H. Polatoglou Physics Department, Aristotle University of Thessaloniki ABSTRACT The progress of ICT provides tools for improving the quality and the ease of access to education and training. On science teaching, data acquisition systems provide a powerful tool for measuring and presenting online various physical quantities in school science laboratories. But these systems are in general quite expensive and sophisticated for students’ use. An alternative system is the combination of Scratchboard and Scratch. Both of them have been developed in MIT Media Labs; Scratch Board is a sensor board that comes with several sensors embedded: a light sensor, sound sensor, touch sensor, and slider. It also has four ports where you can plug in other resistance-based sensors. Scratch is a new programming environment, freeware , which and can be used by kids to create their own animated stories, video game and interactive art 197

and share their creations with one another across the Internet. In this work we present two teaching modules, which are designed and realized using Scratchboard and Scratch. The two modules concern the measurementing of the speed of sound in the air, by wave interference, and the consideration of oscillation’s phenomena. Both of the modules have been implemented in the school laboratory providing reliable measurements and getting engaging the students in a higher level than the usual one. We are in the process of preparing a new set of activities on subjects like optics, heat and electric circuits.

OUTCLASSROOM INSTALLATIONS FOR LEARNING PHYSICS LEARNING ENVIRONMENT Mirjana Bo ¢i¶1, Marko Popovi ¶1 and Ilija Savic

2

1. Institute of Physics, Pregrevica 118, 11080 Belgrade, Serbia, [email protected] 2. Physical Society of Serbia, Pregrevica 118, 11080 Belgrade, Serbia ABSTRACT The necessity to utilise wider school space for physics and science education has been identified during last decades by many educators. Authors of articles in Deck the Halls columns in Physics Teacher, published from 1972 to 2001 and collected by Pizzo [1], proposed many devices for demonstrations along the hallway. European Physical Society published posters of biographies of famous European physicists to be used in laboratories and halls [2]. A set of cognitive installations and patterns suitable for spreading the physics laboratory throughout the school building and its courtyard was described in [3-5]. The set includes a globe in the school yard having the same orientation in space as the Earth [5], a dome for recording annual motion of the Sun on the celestial sphere [3], a column for pendulum experiment with essential geographical data and symbols [3], two dimensional patterns for teaching geometry and basics of infinitesimal calculus [4], three dimensional patterns inspired by crystal structures, fountain for teaching the laws of hydrodynamics [4] etc. From their side, architects initiated and cordially have been carrying out innovative school design, as well as improvement of learning environment as a whole [6]. Good learning environments facilitate, enrich and refine learning and creative thinking [1,2]. The concept of an experimental zone for developing the human senses, proposed by Hugo Kukelhaus, writer, sociologist, architect, philosopher and artist, lead to creation of Play Stations for Developing the Senses [7]. Because of anthropomorphic structure of physics, many of these play stations are very useful for physics education [ 7]. Aesthetic appearance of play stations make them useful for art education, as well. Designers of NUS school for mathematics and sciences, erected in 2005 in Singapore, accepted hole-heartedly the concept of a school as a 3D lecture book of science [8]. In this work we propose and elaborate, along the lines presented above, more devices and installations: globe sundial as a successor of spherical sundial; platform for teaching the law of conservation of angular momentum; a cone with characteristic sections for teaching classification of orbits in the gravitational field, weather recorder - a sphere collecting sunrays to burn a plate; moving rainbows maker consisting of: a photocell, electromagnet, gear mechanism and a transparent multi face crystal. Schools possessing such installations and educative devices could have new function and role in the community by creating a network of school based science canters – a kind of a distributed science museum.

MODERNIZATION OF EXPERIMENTAL PHYSICS IS A NECESSITY. IT PLAYS AN IMPORTANT ROLE IN CREATING STANDING COMCEPTS IN THE SCIENCE OF PHYSICS How important is Experimental Physics in teaching and learning Physics. Some aspects that we need to consider. Violeta Halilaj “Kristal” University, Tirana , Albania ABSTRACT “The test of all knowledge is experiment. .Experiment is the sole judge of scientific ‘truth’. ” Richard Feynman In an oral presentation I want to speak and to emphasize the role of experiments in both teaching and learning the laws of Physics. Demonstrative experiments and laboratory courses are at disposal of both teachers and students and they have to use them efficaciously to reach the goals. The laboratory courses are very different from lecture courses. The students explore, usually working together in groups of two, some of the consequences of the physics concepts and principles 198

developed in the concurrent lecture courses. The laboratory experience is simple and direct, consistent with the need to make measurements, as well as to acquire and analyze quantitative data. The idea is that this exploration by the students leads to a much deepened understanding of the laws of physics. The experiments contribute to achieving this objective. Updating the experiments, in technology and concepts, is usually a continuous task. During the last several years computers are installed in our laboratory classrooms. There are some ways we can use them in experiment. The need for modernization consists in: ● The use and value of informatics’ tools, such as: 1. real time experiments display tools. Students work collaboratively to collect and display data from real experiments graphically and numerically in real time and to analyze data and develop mathematical models. 2. and simulation software, an easy-to-use method, which includes state-of-the-art pedagogy, a perfect complement to traditional physical instructions, a powerful tool for modern learning.. ● Data analysis 1. Error Analysis 2. Graphing Data 3. The use of spreadsheet software for data taking, data recording and data analysis. Some questions in looking at ways tools are incorporated : What are the fits or gaps between the intended or expected use of the tools and the way they are actually used in practice? What is identified as more successful and less successful examples of uses of the tools, and what are the reasons for identifying them as such? I think that a discussion about the teaching experience and development of the laboratory experiments, experiment integrated in our teaching, cooperation among universities would be very helpful.

EVALUATING A PHYSICS TEXTBOOK Analysis of the new school textbook of physics used in 9th grade of the Greek schools Georgios Kountouriotis Secondary Education, 4

th

Lyceum of Kavala

ABSTRACT In this paper we try to analyze a part of the new school textbook of physics used in the 9th grade of the Greek compulsory education. The use of the new textbook in Greek schools was a result of the implementation of the new Cross Thematic Curriculum Framework for Compulsory Education. The new Curriculum Framework for Science in the level of declaration is cross – thematic and constructivist. However, the implementation in the analytic studies program is not really cross – thematic since the organization of Science in disciplines (Physics, Chemistry, Biology and Geography) remains and the only novelty that justifies the term cross – thematic is that some central notions such as system, interaction, change, energy etc are encountered and taught in almost all disciplines. Furthermore, the characterization constructivist for this Curriculum cannot adequately be justified. (Kokkotas, 2004) (Blachos, 2005) The new learning material consists of a student’s book, a laboratory guide, a workbook and a teacher’s book. The part of the student’s book “Physics C Gymnasiou” (Antoniou, N., Dimitriadis, P., Kampouris, K., Papamichalis, K., Papatsimpa, L., 2007) we analyzed is the unit on Electricity pages 9 to 86. The framework for the analysis we used is described by Koulaidis, B., Dimopoulos, K., Sklaveniti S., Xristidou B. in their book “The texts of Technology and Science in Public areas” Ed. 2007. According to these authors school knowledge is a selective transformation of scientific knowledge. This transformation can be studied in the following dimensions: the relation of scientific knowledge to everyday knowledge using the notion of classification, the processing of the language and visual codes using the notion of formality and the control of the pedagogical relations using the notion of framing. Classification defines the degree of the distinction between the boundaries of categories. (Bernstein, 1991) Strong classification means that the distinction between categories is clear and unambiguous. Weak classification means that the boundaries between categories are vague. In analyzing the textbook, we investigate the way the distinction of scientific and everyday knowledge is presented in the textbook. In case the distinction is clear then classification is strong and the text is scientifically specialized else classification is weak and the text is not scientifically specialized. The formality of the language code is high when it can allow an almost one to one relationship between signifier and signified. The use of scientific language, the use of the symbolic mathematics code and processed rules of grammar and 199

syntax are indications of high formality. Framing refers to the control of the pedagogic rules between the teacher and the learner. (Bernstein, 1991) These rules can be distinguished in rules of hierarchy and didactic rules. Framing is strong, when the locus of control lies with the transmitter (teacher) and framing is weak when the locus of control lies with the acquirer (learner). The texts in any science textbook differ in the language style and structure and can be characterized as reports, experiments or historical accounts. (Koulaidis, et al.) The units of analysis we used were the units in which the authors of the book divided the text. We found 100 units of analysis (excluding questions and exercises) in the unit of Electricity of the textbook. We classified 82 of them as reports, 12 as experiments and 6 as historical accounts. The texts in most reports were classified as having high scientific specialization and medium formality. The pedagogic relations that the textbook imposes viewed as relations of power were in most cases weakly framed. The conditions of partnership of the student to the learning process varied and were either strong, medium or weak.

EXTRA CURICULAR ASTRONOMY EDUCATION OF MOTIVATED PUPILS AT ELEMENTARY SCHOOL LEVEL AS AN ACTIVITY OF CELEBRATING THE IYA 2009 IN THE SARAJEVO CANTON Zalkida Hadzibegovic Univfersity of Sarajevo, Faculty of Science, Sarajevo, Bosnia and Herzegovina ABSTRACT Education in astronomy is not included in current official elementary school curricula. This paper shows how a small group of physicists attracts both pupils and their teachers to participate in extra-curricular activities and informal teaching methods in order to learn astronomy. Pupils and their teachers who participated in seminar activities that were organized during the celebration of the International Year of astronomy 2009 (IYA 2009) in Sarajevo gained important knowledge in astronomy and methodology that will help in wider popularization of astronomy in our country.

DERIVING ACCESSIBLE SCIENCE BOOKS FOR THE BLIND STUDENTS OF PHYSICS Georgios Kouroupetroglou and Hernisa Kaccori National and Kapodistrian University of Athens, Department of Informatics and Telecommunications, Accessibility Unit for Students with Disabilities ABSTRACT The field of physics, and more general science and mathematics, have traditionally been inaccessible for the blind students. The education on those disciplines is highly based on visually-presented concepts and information. The lack of both proper access to educational resources and widespread availability of books in accessible formats in these domains comes with very difficult to read, write and learn physics and mathematics for blind persons. On the other hand, recent studies showed that blind and visually impaired students have the same range of cognitive abilities as sighted students and with proper inclusion and accessibility accommodations they can master higher-order science concepts as well as sighted students. This problem starts in the primary school and gets progressively worse as pupils move towards higher education. Maths get more complicated and necessitate much more sophisticated and technology-based ways to be represented for people with total or partial visual loss. Essentially, access to science information, and most important to the relative educational books, has become the bottleneck which embarrasses the entrance of blind students in physics studies. Thus, only rarely blind students choose to attain a high level of competence in physics and mathematics. Making physics books accessible is a significant challenge, mainly due to the fact that, on one hand mathematics encompass a 2-dimensional and even a spatial nature and on the other hand both the Braille code and the synthetic speech, which are their common renditions, comprise inherently a linear nature. Furthermore, science books contain graphics, diagrams, drawings, pictures and photographs which have also to be delivered in an accessible tactile or acoustical format. Recently, significant progress has been made on the computer based assistive technology that facilitates the production of accessible science books. In this work we present a novel, based on the principles of Universal Design or Design-for-All, multilingual, and 200

integrated methodology for the design, development and production of accessible physics and science books, that supports: ❖ Static Accessibility: the physics and science content is statically converted into a format that is reproducible either on computer based Braille embossers and other tactile devices, or on real time assistive devices, such as refreshable Braille displays and kinaesthetic assistive devices. In this approach, the document is rather viewed as a passive entity, like a printed document presented to a sighted user, while the active component is represented by the blind or visually impaired student, who uses an appropriate assistive device to browse the document, move around it and read its content. ❖ Dynamic Accessibility: the physics and science content is presented in a dynamic, interactive mode using synthetic speech or other sounds (including auditory icons, earcons or other sonification rendering). These approaches require a conversion process which allows the user to navigate through the mathematical content in accordance with its mathematical structure. In this case, the document itself becomes an active component; by performing intelligent transformation of the document, its semantic structure is exposed and information overload on the user is reduced. ❖ Hybrid Accessibility: essentially is a combination of the static and the dynamic accessibility. The above methodology supports the available international standards, like: MathML (Mathematical Markup Language), Math/Science Notation Braille Codes (Nemeth, Marbourg, Stuttgart, Unified English/UEBC), DAISY (Digital Accessible Information System) / ANSI/NISO Z39.86 and the Universal Design for Learning (UDL) Guidelines. It can produce Embossed (or Tactile Books), Digital Talking Books (or Digital Audio Books) as well as Acoustic-Tactile Books not only for the blind and visually impaired students but for all the print-disabled students of science departments. This methodology has been successfully applied in the case of blind students of Physics, Mathematics and Informatics in the University of Athens.

INTERACTIVE VERSUS TRADITIONAL EDUCATION IN TWO GROUPS OF SECONDARY SCHOOL STUDENTS IN SARAJEVO Zalkida Hadzibegovic University of Sarajevo, Faculty of Science, Sarajevo, Bosnia and Herzegovina ABSTRACT How successfully are we educating our students is the key question in the actual process of reforming both educational system and teaching methodology. This study presented representative examples of educational research on three different but important aspects: conceptual understanding of photoelectric effect, basic understanding of the photon model of light and transfer information. Research was carried out within two groups of secondary school students in Sarajevo. One group of students had traditional lectures, whereas the other participated in interactive teaching and learning with a PhET computer simulation. Both groups of students were tested immediately after the session and “interactive group” scored significantly better. This shows the importance of continuous reform and development of teaching methodology in physics based on physics education research.

INTERNATIONAL CLUB LISE FOR ATTRACTING GIRLS TO PHYSICS Zalkida Hadzibegovic Department of Physics, University of Sarajevo, Bosnia and Herzegovina

Tanja Tajmel Department of Physics Education, Humboldt-Universität zu Berlin, Germany ABSTRACT International Club Lise (CL) is a working group of female high school students grade 10-13 on scientific topics. CL was established as part of the EU funded project PROMISE (Promotion of Migrants in Science Education) at universities in Berlin, Sarajevo, Vienna and Istanbul. CL is supposed to act as a promotion of female students, especially of those with background of migration. The regular Club Lise meetings give the opportunities to meet female university students, teachers, scientists and researchers, to work together on scientific topics and to strengthen the competencies and interests of the female highschool students in science. Additionally to the regular monthly meetings annual international meetings took place. These International Club Lise Conferences were organized in 2006 by the Department of Physics Education at Humboldt-Universität 201

Berlin and in 2007 by the Department of Physics at the University of Sarajevo. CL activities include work at laboratories, attending lectures, workshops and international cooperation of all CLs on selected topics of science but mostly on physics. A comparative analysis on the percentage of women working in the field of physics in Germany and Bosnia-Herzegovina (BiH) pointed out the gender gap in physics is remarkably lower in BiH than in Germany. We were investigating possible reasons for this finding and started a survey among female German and Bosnian students on interests and on the views on science as well as on the intentions to study physics. It appeared that physics is the favorite subject and first choice for studies for Bosnian female students, contrary to German female students, where the interest in physics is very low. In this article we provide an overview of CL objectives and activities as well as first outcomes of our research. Furthermore the extension of International Club Lise and the establishment of new Clubs Lise in other countries at the universities around the world shall be discussed.

A EUROPEAN PROJECT on MATERIAL SCIENCE THE CASE OF THERMAL CONDUCTIVITY TEACHING-LEARNING SEQUENCE A. Molohides

(1),

E. Hatzikraniotis

(2) ,

M. Kallery (3), D. Psillos

(3)

Teachers Academy of Thessaloniki Department of Physics, Aristotle University of Thessaloniki, GREECE (3) Department of Primary Education, Aristotle University of Thessaloniki, GREECE (1)

(2)

ABSTRACT The European Project on Material Science aims at enhancing secondary students’ understanding of scientific inquiry, increasing their interest in science and stimulating their appreciation of relevance of science and the relation between science and technology. Research groups in five different countries are developing and implementing research-based teaching/learning sequences in educational contexts. A characteristic of this endeavor is its focus on investigating partnerships between university researchers and schoolteachers and on innovative approaches towards introducing aspects of Material Science at different levels in compulsory education. The Aristotle University of Thessaloniki group focuses on developing and investigating a Teaching Learning sequence on the thermal properties of materials and specifically thermal conductivity for the lower grades of secondary school. Thermal phenomena, heating, cooling, and related scientific concepts, models and theories, are a topic area that educators and researchers consider challenging for years now, and age appropriate for primary and secondary education. Research based innovative approaches in the topic of Heat and Temperature focus on helping students construct their understanding of the concepts of heat and temperature and their differentiation; other researchers focus on helping students understand Thermal Equilibrium as a central organizing concept in this topic, or focus on students’ integration of experiential and scientific concepts by employing a macroscopic Heat Flow model. In most of these studies, in addition to usual (hands on) experiments, ICT based materials have been used, such as simulated microscopic models, which have opened up new learning opportunities for the students. Less is known about a comprehensive understanding of thermal conduction. Thermal conduction refers normally to heat transfer in solids without mass movement. A comprehensive treatment of thermal conductivity requires some understanding of the basic concepts of in the topic of heat as well as of factors and mechanisms involved in conduction. It is usually beyond the foci of compulsory education curricula. However, from the point of view of introductory Material Science, thermal conductivity is an essential property of natural materials and advanced technology artifacts. The field of application of this process is widespread and involves ceramics and polymers, metals and alloys composites and relevant natural or synthetic materials, artifacts and applications such as glasses, cooking devices, jackets, ceramic ovens, insulating Styrofoam, to name only a few materials whose conductivity affects everyday experiences. From a social point of view, students and adults experience almost everyday phenomena related to conduction in situations like cooking, take decisions about using artifacts such as their jackets or come to familiarize themselves with several newly developed materials which, for example, affect heat losses in their house, school or work. In the context of the European Project on Material Science we have developed a Teaching Learning Sequence (TLS), which is composed by units for teaching thermal conductivity in depth to students. The scientific content has been adapted to students’ conceptions taking into account research results. Units follow the Predict-Observe-Explain strategy and students conduct guided investigations using an enriched learning environment, which consists of extensive use of ICT based tools. Didactically transformed microscopic models depict thermal interactions in iconic, graphic and symbolic forms. Students working in groups, solve problems, explore models and are engaged in classroom discussion on the problem under study, constructing links between evidence and explanations. In this paper the structure of such innovative units will be presented and results showing students’ development in scientific understanding will be reported. 202

EXPLORING “SCIENCE AS CULTURE” THROUGH THE EUROPEAN SCIENCE MUSEUMS Astronomy and Museum Education Dimitra Lelingou, Hellenic Physical Society,Greece Benedek Varga, Katalin Czàr Semmelweis Museum Library and archives of the History of Medicine, Hungary

Seema Sircar, Allan Paterson, Lilian Lindsay, Andy Watson, Christopher Croly Aberdeen City Council Strategic Leadership, United Kingdom ABSTRACT The Hellenic Physical Society is a scientific association with an intensive action in the field of education, which is governed by the philosophy that the relationship between science and society must be interactive. For this reason the Hellenic Physical Society is a partner of the European Grundtvig Lifelong Learning Project/ Learning Partnerships, tilted: Exploring “Science as Culture” through the European Science Museums. The program numbered 07-GRCO1-GR04-000251 constitutes an educational collaboration between the Semmelweis Museum Library and archives of the History of Medicine of Hungary, which is the co-ordinator of the project, the Hellenic Physical Society (Greece) and the Aberdeen City Council Strategic Leadership of United Kingdom. During the first year that the european project was conducted, the Physics Museum of the greek aegean island of Chios, in collaboration with the Second Chance School of Chios, also took part. During the academic year 2008-2009, the Second Chance School of the Koridallos Prison of Athens is also taking part. The basic ideas, the design axes and the first results of the Grundtvig project will be developed in this presentation. This european partnership creates an educational programme consisting of science-related activities (such as seminars, lectures, presentations and in situ experimental activities), and prepares appropriate educational material for lifelong science learning, using innovative teaching methodologies and the European science museums’ exhibits participating in this project, by making them centres of significant cultural contribution to science and society. Using the integrated approach of astronomy teaching as the central design axe in this programme, we highlight the cultural aspects of science education. From our educational intervention we develop educational tools for astronomy suitable for distance learning and making use of new technologies. The partnership is addressed to different age groups: museum visitors, museum educators, teachers involved in adult education, adult school students, financially and socially inferior groups, the general public. It aims at promoting innovative didactic lifelong procedures of informal forms of science education, through the proper utilization of the artifacts on display of the european science museums taking part, to the utilization of teaching procedures with the use of new technologies as didactic tools, to the forming of a cultural network of collaboration and to the creation of life-long learning teaching tools, so as to furhter promote the cultural dimension of scientific knowledge. In this paper a particular reference will be done to the development of a museum educational project of astronomy at the Adults Prisoners of the Second Chance School of Koridallos Prison of Athens and to the way that we try to insert elements of museum education inside the prison’s school. Our main objective is to vivify the science museums. At the same time, we intend to share our experiences and relate our various fields of educational activity, so as to participating in this project. Finally, we intend to cultivate the cultural ideals and perceptions of European citizens, through the exploration of our common cultural past, to raise the awareness in our scientific-cultural heritage and to use this heritage as a powerful unifying field for us all.

ASPECTS OF MICROSCOPIC MODELS IN THE TEACHING OF PHYSICS THE CASE OF POLARIZATION AND THERMAL CONDUCTIVITY E. Petridou (1)

(1)

, E. Hatzikraniotis

(2)

, A. Molohides

(3)

, D. Psillos

(1)

Department of Primary Education, Aristotle University of Thessaloniki, GREECE (2) Department of Physics, Aristotle University of Thessaloniki, GREECE (3) Teacher’s Academy of Thessaloniki, GREECE

ABSTRACT ∆here is high international research interest in modeling and use of models in education with the researches to point out the significance of models as didactic tools and their ability to contribute to students’ cognitive evolution and to effective learning (Hestenes, 1997; Justi, 2005). Models and the process of scientific modeling are core components of scientific inquiry. Instructional approaches that are grounded on the premises of modeling-based learning engage students in the 203

authentic practice of using models as tools for visualization, explanation or prediction. When a model is used for visualization contains characteristics of the object that represents, it looks and/or functions like it, when a model is used for explanation contains the essential characteristics that helps the understanding of the phenomenon and when it is used for prediction helps the user to check his hypothesis and predict the phenomenon. It is known that microscopic model-simulations can help students to build mental models on physical systems, and, in addition, they can help students make sense of translations between different representations of physical phenomena. Regarding models and modeling, research is still going on, addressing the long-standing problem of an effective use of microscopic models by teachers and students to explain and predict physical phenomena in school topics. Students and student-teachers face difficulties in providing explanations and predictions by using of microscopic models and employ these at different levels of understanding as for example in the case of electrostatic interactions (Barbas & Psillos, 2003). In this work we examine some aspects of using of microscopic models-simulations in the teaching of Physics. We examine two case studies, namely, the case of electric polarization and the case of thermal conductivity. In either case, microscopic models have been developed as Flash simulations. In the case of electrostatic polarization, we are addressing the problem of the conceptual difficulties that even university students come across in understanding the rearrangement of the charge in a body. We have developed 3 adapted to students interactive representations of a simulated model of electric polarization in order to gradually introduce students from the “atom” to the “dipole” and finally to the “insulator”. In the case of thermal conductivity we have developed an adapted to students series of microscopic models-simulations, where we address the concept of heat transfer in a solid, the role of electrons in heat transfer in metals (as opposed to ceramics), the case of material’s density, and the heat transfer in crystalline vs. amorphous materials. In both cases students are involved in model exploration rather than in model construction, however in electric polarization the “predictive” use of models has been adopted while in the case of thermal conductivity the approach emphasized “visualization - explanation”. The simulations and their use will be presented in the conference. REFERENCES Barbas A. and Psillos D. (2003) Evolution of Students’ Reasoning about Microscopic Processes in Electrostatics under the Influence of Interactive Simulations Teaching and Learning in the Science Laboratory ed D Psillos and H Niedderer (Kluwer Academic Pub)

pp 243-54 Hestenes D. (1997) Modeling methodology for physics teachers Proceedings of International Conference on Undergraduate Physics Education ed. E.F. Redish and J.S. Rigden (The American Institute of Physics NY) pp 935-57 Justi S.R. and Van Driel J.H. (2005) The development of science teachers’ knowledge on models and modelling: promoting, characterizing and understanding the process. Int. J. Sci. Educ. 27 549-73

EDUCATION AND RESEARCH IN THE SEENET-MTP REGIONAL FRAMEWORK FOR HIGHER EDUCATION IN PHYSICS R. Constantinescu and G. S. Djordjevic

*

Department of Theoretical Physics, University of Craiova, 13 A. I. Cuza Str., Craiova 200585 Craiova Romania * Department of Physics, University of Nis, P.O.Box 224, Nis, Serbia Southeastern European countries undergo significant changes in the demand/supply ratio on the labour market and in the structure of professional competences that are necessary for undertaking a professional activity. In addition, brain-drain process and decrease of interest for a career in basic sciences put many challenges for our community. Consequently, based on the activity of the Southeastern European Network in Mathematical and Theoretical Physics (SEENET MTP Network) in connecting groups and persons working in mathematics and theoretical physics, we investigate specific qualifications recognized in these fields in all the countries from the region, and the related competences necessary for practising the respective occupations. A list of new possible occupations will be promoted for inclusion in the National Qualifications Register for Higher Education. Finally, we analyze the vision existing in this region on the higher education qualifications against the European vision and experience, in particular in training of Master students, PhD students, and senior teaching and research staff through the Network, i.e. multilateral and bilateral programs.

204

SOME REFLECTIONS ON THE ORIGIN, MEANING AND IMPORTANCE OF THE FIRST RATIONAL EXPLANATION OF THE WORLD GIVEN BY THE MILESIAN PHILOSOPHERS S. Sakkopoulos

*

and E. Vitoratos

Department of Physics, University of Patras, 265 00 Patras, Greece ABSTRACT It is generally believed that the birth of Greek Philosophy took place in Miletus in the first half of the 6th century B.C. There, began to take shape in human mind the conviction that behind the extreme perplexity of events, which according to religious myths were due to the actions of powerful, capricious and morally imperfect deities, there must be an underlying order, the product of impersonal eternal forces. Moreover, human reason was considered by those first philosophers Thales, Anaximander and Anaximenes, probably each one of them pupil of the former, the sole and sufficient instrument for the search of natural phenomena. They considered as the basic substance of everything, i.e. the most basic material element, from which all things emerge and to which ultimately return, the water (Thales 624 – 546 B.C.), an unobservable, undefined element, the boundless (Anaximander 610 – 546 B.C.) and the air (Anaximenes 570 – 525 B.C.). Although their cosmologies were different, their cosmogonies were evolutionary, not creative involving a god standing apart from the basic substance. The basic substance had the property of change, life and growth, without any influence from outside (hylozoism) [1]. This well known story gives rise to a series of questions, i.e. how sudden was such a big step in human thought, what was the cause of it, what was the economical and sociological situation in Miletus at that time, which elements of religious myths had been incorporated in the new world vision and how were considered the opinions of each of these philosophers by the next one of them. Ancient sources of information about the beginning of philosophy, do not give us any report of a gradual transformation of myths into rational theories. Undoubtedly, any intellectual change has its cause and it is more or less gradual. The lack of information gives rise for much speculation. Miletus was a commercial centre and the economically upper class of merchants, in which most probably belonged the three philosophers, had the opportunity to get in contact with ideas from all over the Middle East and Egypt. A common element in Babylonian, Egyptian, even Greek mythologies (Hesiod) was that everything emerged from an undifferentiated and amorphous substance, usually in the form of a watery cloud. Usually and quite justifiably, it is considered that philosophy and science is a “leisure” activity practiced in times of peace and ease. However, long before the 6 th century B.C. Miletus had to defend herself to the Lydians, had been involved in disputes with neighbouring Greek colonies, had to face the not always peaceful succession of “tyrants” as its governors and during the life of the three philosophers Miletus was harassed by a social conflict between the social classes of the rich citizens (ÏÔ˘Ù›˜) on the one hand and the manual workers (¯ÂÈڈ̿¯·) on the other [2]. The abandonment of religious myths may express the belief that only human reason and not divine intervention could solve problems. Moreover, the difference of the basic substances postulated by the three Milesians reveals another remarkable characteristic of these ancient philosophers. Each ones theory was proposed as a product of human mind susceptible to criticism and change and not as a divine dogma [3]. [1] W.K.C. Guthrie, “A History of Greek Philosophy I. The earlier Presocratics and the Pythagoreans”, 1985, Cambridge University Press. [2] History of the Greek Nation, 2nd Volume, Archaic Hellenism, Ekdotiki Athinon, 1971, pp 245-247 (in Greek). [3] D. Furley “The Greek Cosmologists”, Vol. 1, 1987, Cambridge University Press. * [email protected]

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MODELLING ACTIVITIES IN KINEMATICS Understanding quantitative relations with the contribution of qualitative reasoning Dr. Stelios Orfanos Executive Secondary School Education, [email protected] ABSTRACT In Greek traditional teaching a lot of significant concepts are introduced with a sequence that does not provide the students with all the necessary information required to comprehend. We consider that understanding concepts and the relations among them is greatly facilitated by the use of modelling tools, taking into account that the modelling process forces students to change their vague, imprecise ideas into explicit causal relationships. It is not uncommon to find students who are able to solve problems by using complicated relations without getting a qualitative and in-depth grip on them. Researchers have already shown that students often have a formal mathematical and physical knowledge without a qualitative understanding of basic concepts and relations”. The aim of this communication is to present some of the results of our investigation into modelling activities related to kinematical concepts. For this purpose, we have used ModellingSpace, an environment that was especially designed to allow students from eleven to seventeen years old to express their ideas and gradually develop them. The ModellingSpace enables students to build their own models and offers the choice of observing directly simulations of real objects and/or all the other alternative forms of representations (tables of values, graphic representations and bar-charts). The students -in order to answer the questions- formulate hypotheses, they create models, they compare their hypotheses with the representations of their models and they modify or create other models when their hypotheses did not agree with the representations. In traditional ways of teaching, students are educated to utilize formulas as the most important strategy. Several times the students recall formulas in order to utilize them, without getting an in-depth understanding on them. Students commonly use the quantitative type of reasoning, since it is primarily used in teaching, although it may not be fully understood by them. By modeling activities, we tried to achieve the development of qualitative and semi-quantitave premise and then express magnitude relationships in a quantitative manner. It was observed that students practise semi-quantitative relations, easily can create models and make use of semiquantitave reasoning in an accessible and comprehensible way. They developed a strategy to simplify the situation, by creating simple models containing few relationships contrarily to their original custom to create complex patterns without having fully understood their function.

LEARNING TO EMBRACE NUCLEAR PHYSICS THROUGH EDUCATION Camelia Avadanei “Horia Hulubei” National Institute of Physics and Nuclear Engineering, Nuclear Training Center ABSTRACT Due to its achievements, nuclear physics is more and more present in life of every member of the society. Its applications in the medical field and in nuclear energy, as well as the advanced research, always pushing the limits of science towards micro cosmos and macro cosmos, are subjects frequently presented in the media. In addition to their invaluable benefits, these achievements involve also particular rules to prevent potential risks. These risks are also underlined by the media, often being presented in an unfriendly manner. Specialists in nuclear physics are familiar with these problems complying with the specific rules in order to reduce risks at insignificant levels. The development of a specific field (“Radiation protection”) defining norms and requirements for “assuring the radiological safety of the workers, population and environment”, and its dynamics represent a proof of a responsible attitude regarding nuclear safety. Dedicated international bodies and experts analyze and rigorously evaluate risks in order to draw the right ways of managing activity in the field. The improvement of the formal and informal education of public regarding the real risks of nuclear applications is very important in order to understand and better assimilate some general rules concerning the use of these techniques, as well as for their correct perception, leading to an increase of interest towards nuclear physics. This educational update can be started even from elementary school and continued in each stage of formal education in adapted forms. The task of informing general public is to be carried out mainly by specialists who, unlike 30-40 years ago, can rely on a much more efficient generation of communications’ means. Taking into account the lack of interest for nuclear, an attractive way of presenting the achievements and future 206

possibilities of nuclear physics would contribute to youth orientation towards specific universities in order to become next generation of specialists in the field. Facing new challenges, society becomes aware of the fact that education represents the real solution to escalade them. Nuclear physics plays an important role in ensuring energetic resources for the near future and in reducing greenhouse effects. On the other hand, especially nuclear physics will permit to solve the enigma of universe birth. As in any other field, development involves continuous education and knowledge upgrading for all categories carrying out nuclear activities. For radiation protection workers and specialists, periodically refreshment courses are mandatory, in compliance with the national and international specific requirements.

TEACHING PHYSICS EXPERIMENTS IN PRE-SERVICE PHYSICS EDUCATION: CHALLENGES AND DILEMMAS EXPERIENCED BY PHYSICS STUDENTS Olga Gioka Physics Department, University of Ioannina ABSTRACT This study builds upon literature on physics teacher education and its current concern about the preparation of future physics teachers to teach in secondary education. According to McDermott and her colleagues (2000), teachers tend to teach the same way they were taught in school. Consequently, if we want our future teachers to teach in a different or better way, we have to teach them that way in undergraduate physics classes. In addition, we build on principles and implications by the curriculum development of ‘Advancing Physics’ designed by the Institute of Physics in the UK (Ogborn, 2002) and a series of professional development programmes in the Institute of Weizman (Hofstein et al, 2004) in Israel. In our Department, an initiative has been taken to teach students how to teach physics experiments in secondary education with the goal to develop ‘concepts of evidence’ in pupils (Gott and Duggan, 2003). By the term of ‘concepts of evidence’ we refer to the notion of quality of obtained evidence, the quality of graph construction, interpretation and use, and the quality of the analysis of evidence and the evaluation of the whole experiment. Gott and Duggan underlined that the teaching of ‘concepts of evidence’ has to be explicit to pupils in the laboratory work in high school. To put it simply, how we uld teach pupils how to draw a graph, how to interpret it, to use it in the analysis of evidence and the evaluation of the experiment. After a detailed development of the module “Teaching physics experiments to pupils in high schools” we have proceeded to the teaching itself to the physics students and prospective secondary teachers in our Department. The module belongs to the pre-service teacher education of our Undergraduate programme of Study and it addresses important issues closely related to the role of the teacher. For instance, how much freedom the teacher can give to pupils for them to make the planning of the experiment, how much help and support when they carry it out, how he organizes the teams in the laboratory. We ask students to operate and think like teachers and, consequently we expect them to plan and discuss how they will teach specific physics experiments by giving them enough freedom and choice in contrast to the experiment in the type of recipe (Etkina et al, 2002). Although the school experiments are relatively easy compared to the ones that students are involved during their overall study in Physics, our physics students have difficulties in planning an experiment without help. It may be the case that they carry out experiments in the lab with full description. The main research question is about the difficulties and needs of physics students in relation to their preparation to teach physics experiments to high school pupils. The research methodology includes lesson observations, individual interviews with the participants and collection of their portfolios (Lunetta, Hofstein and Clough, 2007) over a period of an academic year. Our aim has been to systematically explore students’ concerns, needs and difficulties when they prepare their class for an experiment and guide their pupils to plan it, make a hypothesis, support them in the actual data collection, graph construction and analysis of evidence. Particular attention has been given to the research ethics and the associated issues (anonymity of the participants, the role of the researcher). The reliability of the analysis is based on the triangulation of the three methods of data collection and analysis.

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TIME FOR EDUCATION: ONTOLOGY, EPISTEMOLOGY AND DISCURSIVENESS IN TEACHING FUNDAMENTAL SCIENTIFIC TOPICS Katerina Plakitsi*, Vasilis Kokkotas**, * Assistant Professor, University of Ioannina, Greece, **PhD, University of Athens, Greece ABSTRACT Science has the character of construction of explicative normative models, whose semantic value is assessed instrumentally, through the quantified corroboration of predictions, or their compliance with the facts, constituting a separate world. But we oppose to its approach as a “logistic” activity, depraved of any ontological substantiation, since, this would ignore the meditative or interpretive features salient in it. The ontological appropriation of the world is a multidisciplinary task, which cannot be integrated without a form that combines argumentation with a meaningful discourse, open to culture. The view of learning science as culture acquisition affords an intuitive, holistic, and rich appreciation of students’ experiences in a science classroom. Common cultural mediators in science education are narratives. McClosky and Bruner have been long-time advocates of the use of narrative in education. As a case study, we applied a both cultural and ontological approach to the teaching of time in primary education.

ON THE PREEXISTING KNOWLEDGE LEVEL OF FUTURE SCIENCE TEACHERS’ ABOUT BASIC ASTRONOMY CONCEPTS Olcay TÜRKO ¤LU 1, Murat GÖKDERE 2, Nevin SÜLEYMANO ¤LU 1, Metin ORBAY 2* 1 Department

of Science Education, Faculty of Education, Ondokuz Mayis University, 55100 Samsun-TURKEY of Science Education, Faculty of Education, Amasya University, 05189 Amasya-TURKEY *e-mail: [email protected]

2Department

ABSTRACT A curriculum to train teacher candidates is very important factor to develop teacher candidates’ conceptual understanding of scientific concepts because they have a dramatic impact on students’ ability to understand and construct new knowledge of scientific concepts. The aim of this study was to determine the preconceptions and misconceptions of teacher candidates about basic astronomy concepts, by using validated diagnostic questions in the last version of the Astronomy Diagnostic Test 2.0 [1] to 113 teacher candidates in school of education in Amasya University, Turkey. The findings indicated that teacher candidates held a series of misconceptions on several basic astronomy concepts. After common misconceptions were identified, a constructivist-inquiry approach to teach basic astronomy concepts in the astronomy curriculum for pre-service teachers was proposed. [1] Adams, J., Lindell, R., Brick, C., et. al.,(1999) Astronomy Diagnostic Test (ADT) Version 2.0, http://solar.physics.montana.edu./aae/adt/ADTv2.0.PDF

SCIENTIFIC METHOD IN TEACHING PHYSICS IN LANGUAGES AND SOCIAL SCIENCES DEPARTMENT OF HIGH - SCHOOLS Mirko G. Nagl 1, Du £anka ›. Obadovi ¶2, Maja Stojanovi ¶2 1 ‹abac High School, ‹abac, Masarikova 13, [email protected], Serbia 2

Department of Physics, Faculty of Sciences, University of Novi Sad, Trg D. Obradovi ¶a 4, [email protected], Serbia

ABSTRACT The expansion of scientific materials in the last few decades, demands that the contemporary educational system should select and develop methods of effective learning in the process of acquiring skills and knowledge usable and feasible for a longer period of time. High-schools (gymnasium) as general educational institutions possess all that is necessary for the development of new teaching methods and fitting into contemporary social tendencies. In the languages and social sciences department in high schools (gymnasium) physics is the only natural sciences subject present during all four years. The 208

classical approach to teaching is tiring as such and creates aversion towards learning physic when it deals with pupils oriented towards social sciences. The introduction of scientific methods raises the motivation to a substantial level and when applied both the teacher and pupils forget when the class starts or ends. The assignment has shown the analysis of initial knowledge of physics of the pupils attending the first grade of languages and social sciences department of the high school (gymnasium) as a preparation for the introduction of the scientific method, the analysis of the initial test with the topic of gravitation, as well as the analysis of the final test after applying the scientific method through the topic of gravitation. The introduction of the scientific method has duly justified the expectations and resulted in increasing the level of achievement among the pupils in the experimental class.

THE PROBLEM SOLVING METHOD IN TEACHING PHYSICS IN ELEMENTARY SCHOOL G. Hajdukovi ¶ Jandri ¶1, D.‹. Obadovi ¶2, M. M. Stojanovi ¶2 1 Primary

School “Miroslav Anti ¶”, Futog, Rade Kon ™ara 2 of Sciences, Department of Physics, Novi Sad, Trg Dositeja Obardovi ¶a 4, [email protected]

2Faculty

ABSTRACT The majority of the teachers ask if there is a “best” known way to teach. The most effective teaching method depends on the specific goals of the course and the needs of the students. An investigation has been carried out to compare the effect of teaching selected physics topics using problem-solving method on the overall achievements of the acquired knowledge and teaching the same material by traditional teaching method. The investigation was performed as a pedagogical experiment of the type of parallel groups with randomly chosen sample of students attending grades eight of the Village Primary School “Miroslav Anti_“ in Futog. The control and experimental groups were equalized in the relevant pedagogical parameters. The obtained results were treated statistically. A comparison was made of the results of the experimental group, in which physics topics were taught using problem-solving method and control group, taught by traditional teaching method, in respect of the quantity and quality of knowledge and efficiency of the applied methods. The obtained results were treated statistically. The comparison showed a significant difference in respect of the speed of acquiring knowledge, the problemsolving teaching being advantageous over traditional method. The students especially pointed out the importance of independent active participation in the teaching process. The main shortcoming in the application of this method represent the individual differences among the students in the speed of solving the given problem, as well as the shortage of the appropriate teaching software which would support this form of teaching.

PRESENTATION OF BASIC THERMODYNAMICS LAWS BY SIMPLE EXPERIMENTS APPLYING PROBLEM-SOLVING TEACHING METHODOLOGY Danijela Radlovi ¶ ¤ubrilo 1 , Du£anka Obadovi ¶2, Davor ¤ubrilo 1 2

1 Technical School Kikinda, Serbia Department of Physics, Faculty of Sciences, University of Novi Sad, Trg D. Obradovi ¶a 4, [email protected], Serbia

ABSTRACT This paper presents several simple experiments in thermodynamics that enable students to accept and understand the basic thermodynamics laws and their practical application in an obvious way, through active learning by solving problems. The experiments described in the paper represent a complete research work that allows students to be gradually introduced to this field of physics. For the experiments, besides the basic laboratory equipment, simple devices (such as plastic syringe, thermocouple and digital voltmeter) are used. It is suggested to work in small groups of students (with teacher coordinating their work) using handouts containing the problems, directions for the experimental work and questions guiding students to problem solving. The final stage of the work involves analysis of the groups’ results through a discussion and mutual reaching the conclusion including teacher’s cooperation. The emphasis is put on active learning which places a student in the position of a subject thus enabling development of his/her total psychological and physical potentials.

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SCIENTIFIC KNOWLEDGE OF THE 18 TH CENTURY THROUGH MARKIDES – POULIOU BROS PUBLICATIONS Author names Kalliopi Bonta Tel: 2465047075, [email protected] Anastasia Chatzizisi T el: 2465047075, [email protected] Stergios Antoniadis Tel: 2465047075, [email protected] Panagiotis Perpesas Tel: 2465047075, [email protected] Konstantinos Tilaveridis Tel: 2465047075, [email protected] Institute Environmental Centre of Siatista ABSTRACT The first saved Greek newspaper, “EFIMERIS” was published by the brothers Markides – Pouliou, in 1790, in Vienna. Aim of this newspaper, according to the publishers - journalists, was the information of its readers about the world events. Simultaneously with “EFIMERIS”, the publishers show great publishing activity and their publications are distributed all through the Balkans. Their Greek publications are sometimes signed with the name Baumeister and other times with the name of Markides – Pouliou, while publications exist with no sign of a printer, and are said to belong to the two brothers. Many of their publications, along with most of the “EFIMERIS” issues were found in libraries in Greece and other Balkan countries, while latent publications exist, also. Through these publications the scientific knowledge of the 18th century was spread in the Balkan countries. The Environmental Group of the Environmental Centre of Siatista, participating in the program “EFIMERIS – Press and Environment”, studies the newspaper “EFIMERIS”, along with other publications of the same printers, in an effort not only to show their role in the presentation and solution of that period’s problems, but also, the role of today’s press and media in the presentation and solution of contemporary problems. Tracing lost friends of “EFIMERIS” and other publications would greatly help us in obtaining a more complete knowledge. That is the reason why we call for the help of colleagues from other Balkan countries, searching libraries and old stores. If any relevant documents are traced, we would be most thankful, if you contacted the Environmental Group of the Centre in the following mail: [email protected] [email protected]

COMPARISON OF ELECTRICAL AND SPECTRAL CHARACTERISTICS OF INTEGRATED FLUORESCENCE LAMP AND COMMON LIGHT BULB Atanas Tanu £evski a and Stojan Rendevski

b

a Institute

of Physics, Faculty of Natural Sciences and Mathematics, University “St. Cyril and Methodius”, Gazi Baba, bb. 1000 Skopje, [email protected], FYR Macedonia b Faculty of Electrical Engineering, Goce Delcev University, Krste Misirkov bb. P.O. Box 201 Stip, [email protected], FYR Macedonia

ABSTRACT For the purpose of acquainting the students of applied physics and students of teaching physics with the electrical and spectral characteristics of two widely used lamps – integrated fluorescence lamp and common light bulb, characterization of the lamps were done by measuring the spectral irradiance and constructing the voltage-current characteristics. Breaking voltage, electric resistance, energy efficiency, energy consumption and intensity spectral distribution, were determined. Also, the quantity of mercury present in the fluorescence lamp was determined by analysis of the spectral characteristics. The advantage of the fluorescence lamp over the common light bulb was shown through comparison of the examined parameters of the two lamps.

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KEY ASPECTS OF THE IMPLEMENTATION OF OPTIONAL SUBJECT “HANDS ON – DISCOVERING OF THE WORLD ” IN TEACHING PRACTICE OF THE WEST - BA ¤KA DISTRICT IN SERBIA Marija Bo £njak and Du £anka ›. Obadovi ¶* Faculty of Education, Sombor, University of Novi Sad, Serbia, [email protected] *Faculty of Sciences,University of Novi Sad, Serbia, [email protected] ABSTRACT All over the world a number of initiatives have been started which offer new models for improving the quality of science teaching. One of the leading initiatives is “Hands on” which in 2003, included the introduction of the optional subject “Hands on” – discovering of the world into the first four grades of primary schools in Serbia. Five years after it had been introduced in our educational system, the analysis was carried out in order to determine the extent and the way this subject was taught in primary schools of the West - Ba_ka District. The specially designed questionnaire was conducted on the sample of 137 teachers from 16 schools. The analysis shows that this subject is not present enough in teaching practice. This is the case because parents and pupils are poorly informed and mostly uninterested but also because of the widespread mistake that the subject requires special equipment and laboratories. When we analyzed the experience of teachers, we discovered that they were not familiar enough either with its basic principles or with recommended way of realization mainly because of the fact that most teachers did not attend science seminars nor they used appropriate professional literature. In order to increase the presence of this optional subject in teaching practice and to educate teachers for its more quality presentation, it is necessary for teachers to attend seminars about science teaching and to actively cooperate with science teachers at their schools as well as at related colleges.

WORK WITH ADVANCED STUDENTS IN PHYSICS (PRIMARY SCHOOL) Ljiljana Jankovic (1), Dragoljub A. Cucic (2) Primary School “Branko Radi

™evi¶”, Pan ™evo, Serbia (1), Regional Center for Talents “Mihajlo Pupin”, Pan ™evo, Serbia (2)

ABSTRACT Work with the pupils who have special needs is a work that requires special engagement and skills of those who perform it. Work with the gifted children requires outstanding knowledge of a teacher and above all the teachers should be very well informed on the subject they teach, Physics in our case. This work also requires great pedagogical and psychological skills so that these talented pupils would be approached in a suitable way. In this paper we will present to you our methods of teaching Physics to these talented children (13 years old), in the Regional Center for Talents “Mihajlo Pupin” in Pancevo.

SOME APPLICATIONS OF THE LAMBERT W-FUNCTION TO THEORETICAL PHYSICS EDUCATION SOME PROBLEMS IN THEORETICAL PHYSICS EDUCATION SOLVED BY THE LAMBERT W-FUNCTION S. G. Kazakova and E. S. Pisanova Department of Theoretical Physics, University of Plovdiv, 4000 Plovdiv, Bulgaria ABSTRACT The basic properties of the Lambert W-function, which has recently been very popular with its applications to physics, have been presented. Some applications of this function, which can be used in theoretical physics education have been cited and described while others have only been cited. In addition, new examples of the applications of the Lambert W-function in theoretical mechanics and statistical physics have been offered.

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BROWNIAN MOTION, FRACTAL STRUCTURE AND EINSTEIN’S FORMULA VERIFICATION 1Dragisa 1High

School Pirot, 18300 Pirot, Serbia and

Nikolic and

2Ljubisa

2Department

Nesic

of Physics, University of Nis, 18000 Nis, Serbia

ABSTRACT A presentation of experimental verification of Einstein Smoluhowski equation for, Brownian motion is presented in this article.A solution of latex in water and glycerol in alcohol is used while observing and recording is done with binocular optical microscope and with a digital camera.Video materiel is saved in separate files which are set up on the Internet and can be download and used in demonstrative purposes or for further threatment on a computer.

ENROLLING IN SCIENCE AND ENGINEERING ACADEMIC PROGRAMS – – MOTIVATING AND DETERRING FACTORS Valentina Pomazan, Doina Mihalascu, Lucian C. Petcu, and Mihai A. Gîr Ovidius University of Constan

†u*

†a, Bd. Mamaia 124, Constan †a 900527, Romania

ABSTRACT We report the results of correlation analyses performed on the student responses to a survey aiming to determine the factors motivating or deterring the young generation in choosing a career in science and technology. The goal of the study is twofold: i) to identify the motives that determine students to enroll in university programs in science and technology and to engage in applied science and engineering careers, and ii) to discover the barriers that manifest at different age levels, preventing students from making such choices. The study was conducted at the Ovidius University and the “Energetic” Technical High School, both in Constanta, Romania, with samples of 257 and 106 students respectively, based on a 38 item online questionnaire (available at http://www.dentomis.ro/sondaj/) and an estimated error of about 5%. The samples selected from the student population are relevant and allow for a wide range of analyses with respect to gender, family and educational background, field of study, etc. The two variants of the questionnaire were set up in order to fit both target groups sampled: the freshman and sophomore students enrolled at Ovidius University of Constanta (Physics, Biosciences, Engineering and Technology majors) and the seniors students registered in the “Energetic” Technical High-School. Based on the correlation analyses performed we discuss the role of the raw models, parents, educators, of the self-evaluation of the personal skills. We also comment on the opinions of the students regarding the role of inquiry, practical activities, group projects, etc. in science education. The message to educators is simple: to make the science classes more attractive, with more illustrative applications. Moreover, the comparison between physics and other sciences, such as mathematics, chemistry, biology, computer science, social sciences and humanities allows us to draw conclusions regarding ways to improve the perception of the former. Funded by the Sixth Framework Programme for Research and Technological Development of the European Community, grant SAS6-CT-2006-042941-UPDATE. *E-mail: [email protected]

ADVANTAGES AND DIASADVANTAGES OF THE TEST METHOD FOR CHECKING AND EVALUATING OF THE KNOWLEDGE, THE SKILLS AND THE HABITS OF STUDENTS E. Y. Halova and R. G. Kobilarov Department of Applied Physics, Technical University, Sofia E-mail: [email protected] ABSTRACT The following report stresses on the advantages and disadvantages of the test method for checking and evaluating the knowledge and the skills of students. The tests are one of the newest and most suitable methods for checking and evaluating – they provide broader scope and higher objectivity; they allow the typical mistakes and difficulties of the students to be 212

discovered; they present the opportunity for self-study and self-evaluation; they allow the student programs and methods of teaching to be improved and much more. On the other hand, the test method has disadvantages: they show the final answer, omitting the mind process of the students that led to this solution; the personal abilities and attitudes of every student cannot become evident from the test alone since the test stresses only on certain characteristics. From the short overview of the advantages and disadvantages of the popular test method in the recent years, we can conclude that this process is suitable for checking and evaluating of the knowledge and the skills of the students on every level of competency only if combined with other methods of evaluation.

ELECTRIC FIELD PRESURE AND ITS APPLICATION IN MATERIAL SCIENCE R. G. Kobilarov and E. Y. Halova Department of Applied Physics, Technical University, Sofia E-mail: [email protected] ABSTRACT In the paper are presented two energy methods that determine the electric field pressure on a conductor. These methods are more understandable for mechanical faculty students, which is why for them it is easier to comprehend the material. It is shown that molecular electric fields of the order of 107 V/m create huge tension (~ 1011 Pa) and they are responsible for the strength of the solids. In this way we introduce electrical picture in determining the strength of the solid and show one of the applications of physics in material science and strength of materials classes.

RESEARCH AND COMPARISON OF VARIOUS NATURAL MINERAL WATER BRANDS Aristotelis Bizopoulos 1 tel: 2310791632, email: [email protected] Athanasios Gousiopoulos 2 tel: 2310309616, email: [email protected] Sotiris Kopatsaris 1 2310664392, email: [email protected] Stylianos Kasampalis 1 tel: 2310246797, email: [email protected] Vassilios Economou 3 tel: 2310211536, email: [email protected] Pashalis Bizopoulos 4 tel: 2310434226, email: [email protected] Anastasios Mandos 5 tel: 2651041695, email: [email protected] George Tsitsias 5 tel: 2310927549, email: [email protected] Phillipas Tsiopoulos 5 tel: 2310462175, email: [email protected] 1. Physicist Radio/Electricians 2. Electrical and Computer Engineering 3. Electronic Engineering 4. Undergraduate student of Electrical Engineering Department in A.U.TH. 5. Undergraduate student of Electronic Engineering Department in A.T.E.I. Department of Electronics Alexander Technological Educational Institute of Thessaloniki, Sindos, 57400 Thessaloniki, Macedonia, GREECE ABSTRACT This project was performed by the electrical measurements laboratory in order that students comprehend the methods of data collection and data processing using spreadsheets. It is going on for a period of two years and is involving labels from natural mineral water brands from Greece as well as from other countries. In the present report, various Balkan natural mineral water brands are compared. A detailed chemical analysis, and extensive comparison results are presented.

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APPLICATION OF INNOVATIVE METHODS TO OPTIMIZE THE LEARNING PROCESS IN PHYSICS FOR STUDENTS OF MEDICINE G. Zlateva, E. Tsankova Faculty of Medicine, University of Sofia “St. Kliment Ohridski” ABSTRACT Unlike chemistry and biology courses in the high schools which occupy the attention and interest of students as they need to achieve maximum results of examinations for admission in higher medical schools, physics remains remain away from their interest. Striving for awakening the interest of students to classes and diversification of the learning process requires the continuous search of new forms of organization of this process in order to fulfill the main task of education: optimal development of each student, creating conditions for creative work with the highest possible productivity. Using innovations in teaching physics, aimed at the purpose of training in non-traditional way and establish the level of utilization of knowledge to the students. This allows rapid identification and compensat of gaps in the knowledge, which in turn leads to a rationalization and a more complete and lasting control of educational content. The aim of the study is analysis and evaluation of the effectiveness of the implementation of innovative educational methods to increase motivation and the quality of teaching physics to students of medicine. The discussion is based on the opinions expressed in surveys of students and results of various forms of feedback.

TRAINING HIGH SCHOOL STUDENTS FOR LEARNING SPECIAL RELATIVITY C.M. Niculae 1 and Marcela Niculae {2 1University

of Bucharest, Faculty of Physics, Bucharest, PO Box MG 11, 077125 Romania, 2 ION BARBU Theoretical High-School, Bucharest

ABSTRACT The Romanian School’s 12th grade Physics Curriculum includes Basic Concepts of Special Theory of Relativity. The present work describes a couple of scripts written in Scilab that could be useful in training high school students for learning this difficult topic. Besides time dilatation and length contraction, by integrating the 3D relativistic set of equations of a charged particle moving in constant electric and magnetic fields the students will learn, for instance, about E cross B drift or the relativistic form of Larmor radius formula. The present script does not take into account the Cyclotron radiation.

ACQUIRING KNOWLEDGE OF PHYSICS BY A HANDS-ON APPROACH IN ROMANIAN PRIMARY SCHOOL Marcela Niculae ION BARBU Theoretical High-School, Nabucului 18, Bucharest, Romania ABSTRACT The present work discusses results of a test concerning the progress of learning Natural Science at the end of the primary cycle in the context of current curriculum in Romania. The test is focused on acquiring knowledge of physics. The test is structured into four items: The first one proposes a virtual experiment for establishing the level of mathematics knowledge of students. As the second and third items the test focuses on the degree of learning through experiments described in the student book. The fourth item tests the acquired knowledge by experiments carried out directly by students. All items have two requirements: a) What happens in the experiment? and b) Explain why. Test was applied to a sample of 120 students from grade IV. The test shows the imperative need to use a Hands-On approach for Assessing Natural Sciences in primary classes.

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COMPLEMENTARY TEACHING OF PHYSICS AND ARTS Dragana Mili ¶evi¶1 LjubÈ £a Ne‰i¶2, 2

1 High School of Kru £evac, 37000 Kru £evac, Serbia, [email protected] Department of Physics, University of Nis, 18000 Nis, Serbia, [email protected]

ABSTRACT ●

Requirements of modern education, interest and understanding of students, the application of knowledge in various fields of physics, changed teacher-student relations impose the need for better understanding of scientific notions and their connections. One of the ways is cooperative learning physics-Fine Arts, which goal is students learning through the interaction which comes with the base of knowledge gained from these areas to become active constructors of new knowledge. The aim of research presented in this paper is to establish the effects of cooperative learning of these two areas and their connections with the topic from the physics and corresponding contents of the art. In this way it is an integral and thematic approach is provided to teaching the same contents from these areas.

GEOMETRICAL OPTICS THROUGH INTERESTING AND SIMPLE EXPERIMENTS 1Tatjana 1Primary

Misic,

2Marina

Najdanovic-Lukic and

3 Ljubisa

Nesic

2 Primary School “Desanka Maksimovic”18000 Cokot, School “Cegar”, Skolska bb, 18000 Nis, Serbia, Serbia and 3 Department of Physics, University of Nis, 18000 Nis, Serbia

ABSTRACT The imperative of today’s education in the field of physics and natural sciences is to overcome the conventional form of teaching which is mostly reduced to students’ repetition of the appropriate lessons. Having that in mind, we are more concentrated on involvement of students in the teaching process through stimulation of their individual way of thinking and the use of knowledge gained through their own experience. The paper describes in detail three geometrical optics experiments that can be explained on the basis of knowledge about the linear propagation, reflection, refraction and total reflection of light. These experiments, although simple to perform, are of problem-solving character because they lead to the paradox between the acquired knowledge and the already experienced one. The results of the experiments attract the students’ attention and make them more interested in the acquisition of knowledge.

POSSIBILITIES FOR ACTIVATING TEACHING OF THE COURSE “METHODS AND TECHNIQUE OF THE SCHOOL PHYSICS EXPERIMENT” Radost Ivanova Vassileva South-West University, Blagoevgrad, Bulgaria ABSTRACT In this paper, a non-conventional approach is proposed for organizing the cognitive activity of students– future teachers, in acquiring methods and technique of the school physics experiment. The purpose is to ensure a specific educational environment in which students have positive attitude to work, show willingness for cooperation and mutual aid, and they actively take part in joint activities regardless of their knowledge, abilities and interests. In the paper, some of distinctive characteristics of the organization of cognitive activity in this case are followed and analyzed: work in small groups; implementation of group tasks, in which, problems with entertaining matter are added to the experimental tasks; discussions within a group as well as among the groups; introducing an element of competition among the groups, etc. Conclusions are drawn about advantages of such an interactive approach for increasing effectiveness of education.

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PHYSICS IN AN INTERDISCIPLINARY APPROACH Drd . Mirela Bulgariu University of Bucharest -Faculty of Physics, Bucharest - Magurele, 077125, Romania Educational Physics Organizing information in a rigid system does not fit the necessity of shaping a general culture with the pupils de declared objective of any educational system. The contribution of each school subject is expressed not by what is specific to it, but by what it shares with other school subjects, what is generalized and transferable. It is on the basis of this general culture that we can achieve profound specializations with efficient and lasting results for the spiritual and material life of the individual and of the society which supports and integrates hem. A first situation which must be solved theoretically is to specify the objective and to define interdisciplinary. According to the dictionary of pedagogy, interdisciplinary is “a report of interpretation (cooperation- coordination) among the school subjects, among the structures of the educational content corresponding to the modern organization of the type of institute of education”. Interdisciplinary does not mean only dealing with a phenomenon simultaneously from the points of view of several ,but also a integrated and integral approach of this each science bringing its own conceptual system, way of thinking and specific methods of research and representation. In order to achieve a good interdisciplinary some exigencies have to be observed: ❖ the teacher should have a thorough general cultural ❖ the teacher should know the methodology of his particular discipline well but also the methodology of the other subjects in the curriculum area ❖ the pupils should be aware of the existence of interdisciplinary of the school subjects ❖ the achieving of some programs with themes of an interdisciplinary character. CONCLUSIONS ● Education should train young people for life ● The process of learning should be pleasant and efficient at the same time ● The contents of tomorrow’s education will admit and incorporate new dimensions and components imposed upon it by the evolution of the society and the problems of the contemporary world. The multidimensional content (physics, chemistry, biology in our case)should be put in order so as to prevent dispersion and overloading. An interdisciplinary approach supposes analysis and selection, team work and perspective orientation.

A COSMIC RAY TELESCOPE FOR EDUCATIONAL PURPOSES S. Kazanas Department of Physics, National & Kapodistrian University of Athens, Greece ABSTRACT Cosmic ray detectors are widely used, for educational purposes, in order to motivate students to the physics of elementary particles and astrophysics. Using a “telescope” of scintillation counters, the directional characteristics, diurnal variation, correlation with solar activity, can be determined, and conclusions about the composition, origin and interaction of elementary particles with the magnetic field of earth can be inferred. A telescope was built from two rectangular scintillator panels with dimensions: 91.6x1.9x3.7cm3. The scintillators are placed on top of each other, separated by a fixed distance of 34.6cm. They are supported by a wooden frame which can be rotated around a horizontal axis. Direction is determined by the coincidence of the signals of the two PMTs. Standard NIM modules are used for readout. The overall acceptance of the detector is calculated using Monte Carlo simulation. This device is to be used in the undergraduate nuclear and particle physics laboratory. The design and construction of the telescope as well as some preliminary results are presented.

216

TRADITIONS AND REFORMS IN BULGARIAN PHYSICS MILKO BORISSOV (1921 – 1998) Ganka Kamisheva Institute of Solid State Physics, 72 Tsarigradsko choussee, 1784 Sofia, Bulgaria, [email protected] ABSTRACT Physics has 120 years history in Bulgaria. University education and research on physics began in Sofia, when the Faculty of Physics and Mathematics established. Experimental physics is the oldest chair in physics at the Sofia University. Emanuil Ivanow initiated first university course on physics at the Faculty of Physics and Mathematics (1889–1890). The base of experimental physics chair built Professor Porphiry Bachmetjew (16 years, from 1890 to 1906), Professor Alexander Christow (30 years from 1909 to 1937) and Professor Georgi Nadjakov (35 years up to 1962). Milko Borissov succeeded to the experimental physics chair (1963–1980), changed the name “solid-state physics”, and preserved tradition in its work. He was born in Sofia on February 18, 1921, studied physics in Bulgaria (1939–1943), specialized crystal growth in Germany (1955) and nuclear physics in Russia (1956/7). Faculty of Physics and Mathematics, situated on the Moskovska Street (1889–1960), had six chairs on Physics (experimental physics, astronomy, meteorology, theoretical physics, nuclear physics and technical physics). When Milko Borissov studied physics, there are two physical Institutes – Astronomical Observatory in the King’s garden and Institute of Physics (experimental physics laboratories; dark room for spectral investigations; electro technical laboratories; meteorological station in the University garden; and a nuclear physics laboratory in a house, situated near – 14 Shipka Street). Milko Borissov took his University degree here and after that, he was Professor Georgi Nadjakov’s assistant (1945–1948) and associate Professor (1957–1963). Later on, he initiated an innovative series of lectures and courses on solid-state physics, acoustical-electronics and acoustical-optics and wrote high school and university textbooks. Because Physics, Mathematics and Chemistry were scattered in the buildings against ecclesiastical school, Losenets district, Milko Borissov read lectures in the Chemistry Campus from 1960 up to the new Faculty of Physics Campus built (1990). Independent Faculty of Physics detached from the old Faculty of Physics and Mathematics in 1963 at the time, when Milko Borissov was dean. In the some years (started from 1948), Milko Borissov organized his research in a new Institute of Physics, created by Bulgarian Academy of Sciences. He investigated many physical problems with one hundred co-authors and made 403 publications in 30 different areas. His research model has cyclic direction between articles, patented inventions, and manufactured technologies. He invented new methods, technologies, and apparatuses, investigated photo dielectric effect, ionic vibrations and waves in gas and solid plasma, phonon spectrums and elastic properties of the semiconductor crystalline. He calculated temperature waves and suggested model for high temperature superconductivity. Reading Bulgarian old church books and manuscripts, he proved that Renascence started in Bulgaria earlier before its appearance in Europe. Professor Milko Borissov became a Corresponding member (1967), and a full member of Bulgarian Academy of Sciences (1984). He was vice-director of the Institute of Physics (1959–1961) and the first director of the Institute of Solid State Physics (1973– 1991). Sections of the Bulgarian Academy of Sciences, reorganized by the low since 21 April 21, 1972, became United Centers. All units (University and Academic Institutes and Laboratories) on the field of physics became part of the Centre of Physics. Milko Borissov was a director of the Centre of Physics (1973–1988). Bulgarian Academy of Sciences put him on the old age pension since March 19, 1991. Now there are ten years from his death on 5 November 1998. The memorial session was hold in 2003, and the book about him published in 2008. The aim of this work is to estimate Milko Borissov’s reforms in all branches of physics in Bulgaria.

217

HEAT STUDIES WITHIN DISCIPLINARY BOUNDARIES: DRAWING AN ANALOGY BETWEEN FRANKLIN’S ELECTRICAL THEORY AND BLACK’S DISCOVERY OF LATENT HEAT Kyriakoula Sakorrafou Part time Academic Staff, Hellenic Open University There are heterogeneous elements of the scientific culture that shaped 18th century Scottish chemist Joseph Black’s (1728-1799) experimental practice on heat in chemical phenomena, and articulated the theory of latent heat. William Cullen, Black’s teacher at the University of Glasgow, taught him the chemical knowledge and experimentation, introducing him to the Newtonian tradition of natural philosophy. In the existing historiographical interpretations the discovery of latent heat is either in accordance to Cullen’s earlier chemical interest or to his later one in an ethereal explanation of chemical phenomena; the latter not being thoroughly investigated. This paper suggests that Black could legitimately speculate and even conduct experiments on an analogy from electricity, following Cullen’s analogy from Benjamin Franklin’s electrical theory. Isaac Newton’s and Herman Boerhaave’s experimental practice and theories in chemistry came under critical scrutiny in the 1740’s and 1750’s at the hands of Black’s immediate Scottish predecessors in the study of heat. This critical stance partly derived from the critical epistemological culture established by David Hume and Adam Smith. This culture was positive to science, favoured experimentation, and created a valid space for analogical, hypothetical thinking within the disciplinary boundaries of the established natural philosophy and the gradually independent science of chemistry. It was this epistemic disposition that might have allowed and encouraged the analogical adaptation of the experimental and theoretical work of Franklin for the science of heat.

HISTORY OF PHYSICS IN SOUTHEASTERN EUROPE DURING THE 18 19 TH CENTURIES. A reappraisal

TH

AN

George N. Vlahakis Institute for Neohellenic Research / National Hellenic Research Foundation Our presentation presents the course of Physics development in the wider cultural area of the Balkans during the 18th and 19 th centuries. Our aim is to show that besides that physics played a critical role in the efforts to make the Balkans an active part of the intellectual and scientific activities in Europe it was also a connecting ring between the different nations of the area. This special role of Physics lasted until the end of the nineteenth century when, due to political and social reasons the map of the Balkans changed dramatically, but still we have the chance to think of science in general and physics in particular as a bridge which unite nations with otherwise different characteristics and strengthens the friendship between people.

PARADOXES OF THERMODYNAMICS Dragoljub A. Cuci ¶ Regional centre for talents “Mihajlo Pupin”, Pan

™evo, Serbia

ABSTRACT The paradoxes of thermodynamics are unavoidable in the study of physical paradoxes because of their importance at the time they came to be as well as the frequency of their appearance in historical studies of physics. In this work paradoxes are presented together with the historical studies of their creation, their solutions are given and they are analysed according to a number of characteristics: is it an exparadox, is it of theoretic or experimental nature, is it a thought experiment and the type of paradox it belongs to.

218

TECHNOLOGICAL TRANSFER FROM RESEARCH NUCLEAR REACTORS TO NEW GENERATION NUCLEAR POWER REACTORS Laura RADULESCU 1, Margarit PAVELESCU 1 “Horia

2

Hulubei” National Institute of Nuclear Physics and Engineering, PO BOX MG-6, Bucharest 077125, Romania 2. Academy of Romanian Scientists, Bucharest, Romania

The goal of this paper is the presentation of the technological transfer role in the nuclear field, this implication being sustained by historical arguments. In this frame, it is very instructive to remind some achievements from the first systems having natural uranium as fuel and heavy water as moderator, and follow the steps during the history to arrive to New Generation Nuclear Power Reactors. Starting with ’40, the accelerated development of the industry has implied the increase of global demand for energy. In this regard, the nuclear energy could play an important role, as it is an essentially unlimited source of energy. However, the nuclear option faces the challenges of increasingly demanding safety requirements, economic competitiveness and public acceptance. Worldwide, a significant amount of experience has been accumulated during development, licensing, construction, and operation of nuclear power reactors. This experience forms a sound basis for further improvements. Nuclear programs in many countries are addressing the development of advanced reactors, which are intended to have better economics, higher reliability, improved safety, and proliferation-resistant characteristics in order to overcome the current concerns about nuclear power. Advanced reactors, now being developed, could help to meet the demand for power in developed and developing countries, not only for electricity generation, but also for district heating, desalination and for process heat. The paper presents some historical examples referring to the steps pursued from first research nuclear reactor to present power reactors, underlining that this progress doesn’t exist if the great discoveries wouldn’t be delivered from nuclear scientists using the technological transfer.

MUSEUM AS A SOURCE FOR HISTORICAL RESEARCH IN PHYSICS IN BULGARIA Ganka Kamisheva Institute of Solid State Physics, 72 Tsarigradsko choussee, 1784 Sofia, Bulgaria,

[email protected]

ABSTRACT Georgi Nadjakov Museum was created by the Institute of Solid State Physics after his death (1981). Physical apparatuses, documents and photographs were preserved in the Museum at first. Vladimir Kusev and Alexander Vavrek charged as museum curators consecutively. The collection of documents of academician George Nadjakov is largest in the museum. They come from his daughter Elka Nadjakova and his daughter-in-law Krasimira Marinova. Academician George Nadjakov sources covered documents from the end of XIX century to the year of his death. Nature of sources is personal. Physical instruments came from the laboratories of academician George Nadjakov at the Sofia University and the Institute of solid state physics. Part of them, are made in physical workshop. We have many imported abroad apparatuses. The oldest artefacts were made in the first half of XX century. Collection of physical books of academician Georgy Nadjakov did not preserve now unfortunately. The family of his daughter Elka Nadjakova bestowed part of his personal physical books on the museum in 2006. The family Elka Nadjakova and Nikola Nikolov supported reconstruction of academician George Nadjakov exhibition hall. New line of history of physics research started in the some time under Professor Milko Borissov leadership. He supervised studiesof research group for historical investigations. The sources, preserved in Bulgarian state archives and libraries and private collections are investigated. Two books and many articles published after that by the group. Statute of museum was changed (2000), and the museum extended collection of documents and sources for other Bulgarian physicists. Artefacts of Razum Andrejchin (2001), Konstantin Stamenov (2003), Alexander Vavrek (2003), Dimitar Stojanov (2005), Emil Nadjakov (2005), Petar Peykov (2006) Josif Rangelov (2008), Antonia Peeva (2008), Svetla Pakeva (2009), Evgeni Learovski (2008) Nikolai Pashov (2009) got in the museum after that. Purpose of this work is to prove Museum as a place with sources for history of physics investigations.

219

KVANTIZACIJA FIZIKALNE VELI ¤INE OD ARHIMEDOVE VODENE VAGE DO AL-HAZINIJEVE “VAGE MUDROSTI” Hrustem Smailhod ¢i¶, Ahmo ¤oli¶ University of Tuzla, Bosnia and Herzegovina ABSTRACT

LEONICO TOMEO – FIRST INTERPRETER AND TRANSLATOR OF ARISTOTLE FROM ORIGINAL GREEK Tatjana Mulaj 1 , Zenun Mulaj 1 Polytechnic

2

University of Tirana, Faculty of Physics and Mathematics Engineering, Department of Physics 2 University of Tirana, Faculty of Natural Sciences, Department of Physics

ABSTRACT In the middle of XIV century, in European Renaissance, it was necessary to study the Aristotle in original Greek, because translations from Arab in Latin had caused considerable alterations in the meaning of original texts. This task in the beginning was trusted to Leonico Tomeo, which, not only opened the way for the studying of the Aristotle in original, but himself made important interpretations about philosophic and social problems and gave his arguments about concepts of natural sciences, as for motion, atoms etc. He translated some works of Plato, Aristotle, Ptolemy etc, from the Greek to Latin. The work of Tomeo gave revolutionary results and prepared the way for the scientific method of Galileo, which from Padua, where worked and lived Tomeo and later, Galileo, propagates in all European universities.

PHYSICS AND TECHNOLOGICAL TRAINING IN BULGARIAN FORGE CRAFT Petya N. Petkova, Keranka G. Velcheva Konstantin Preslavsky University, Shumen, Bulgaria ABSTRACT The contemporary world regenerates and preserves the traditions of decorative – applied art and the national crafts. This brings up young generation and helps them to uncover the sources of national culture. In the commonly educational system the technological training realizes succession of new methods for national and applied art. The aim is examination of the national crafts as technological processes for cultivation of different metal constructions. There are enforced physical laws here. Seven basic groups of forging methods consider in Bulgarian tradition craft as heat treatment, plastic deformation and applying of different tensions. This gives information about morphology of construction after applying of stress, enlarging or decreasing of the linear sizes, structure change and the change of physical and mechanical properties.

220

STIMULATING STUDENT INTEREST IN SCIENCE BY USING NOVEL PRACTICAL APPLICATIONS OF RENEWABLE ENERGY SOURCES AND MODERN SEMICONDUCTOR DEVICES A. P. Skountzos 1,3, P. Yannakopoulos 1, P. A. Skountzos 1 , P. Palla 3 N. Kolivas 2 , N. Nikas 2, N. Pylihos 2, G. Souriadakis 2, 1

2

TEI of Piraeus TEI of Piraeus (Students) 3

Secondary Education

ABSTRACT On one hand, the fact that today everybody is depending in electronic devices to do everyday things, in combination with the fact that our dependence from energy has rise exponentially, on the other hand, energy becomes day by day more expensive. Fortunately technology is progressing fast and gives us the opportunity to develop applications that will help us conserve energy and facilitate our life. This presentation, presents a way to exploit the above mentioned facts, in order to stimulate the interest of students of secondary education as well as of T.E.I. in science by using novel practical applications of renewable energy sources and modern semiconductor devices, two examples of which have been developed in T.E.I. of Piraeus. The first is a novel completely solar powered charger for low consumption electronic devices (mobile phones, MP3 players etc…) and the second is a portable peltier driven and solar powered cooler or heater. Both of these applications work amazingly and their components are visible and so the students can see them. We have observe students of various stages of education to develop an genuine interest in science as they can see firsthand that complex scientific effects can today be easily implemented in practical applications that can be very useful and moreover with a simple guidance of a teacher manufactured by them.

ENVIRONMENT AND ITS REPERCUSSIONS ON HEALTH Maria Sotirakou Primary Education Department, University of Athens As it is well-known for the last decades and more specifically after the World Health Organisation Conference of Health in Ottawa, Canada in 1986, a new holistic framework of perceptions and attitudes towards health has been shaped. This framework does not only specify the absence of illness but the complete physical, intellectual mental and social well-being of the individual which also includes the quality of human relationships, as well as the relationship of the person with his/her natural and social environment. The concept of the quality and the protection of environment is strongly associated with the quality of life and health, in other words with the human dignity. However, the interaction between the environment and the human health is very complex and it is difficult to be appreciated. The interrelation between environmental pollution and the negative repercussions for health-both in a direct and long lasting way- is scientifically proven, even though the cause and effect mechanisms have yet to become completely comprehensible. The change of climate, the destruction of the ozone layer, the declining course of biodiversity and the degradation of soil are some of the reasons which can lead to many serious health problems The search of the impact that the natural environment can bear on a person’s health is not something new. Hippocrates, in his work "On Airs, Waters and Places" defines health as a harmonious balance between the soul, the body and the environment. Plato in his work of "Timaeus" suggests that ‘health is the complete harmony with the universe.’ Alcmaeon of Croton, the leading doctor of the eminent medical school of Croton, defines health and disease as ‘the equality (isonomia) of the opposing powers which make up the body (e.g., the wet, the dry, the hot, the cold, the sweet, the bitter etc.) preserve health, whereas the monarchy of any one of them produces disease.’ Centuries later, scientific research and the theories of those pioneer doctors continue to be current and the human community has realised that healthy individuals develop only in healthy environments. Consequently a holistic approach towards the social and environmental degradation is imperative.

221

SEVERAL EXPERIMENTS FROM THE EDUCATION FOR SUSTAINABLE DEVELOPMENT Natasa Ralic 1, Dragana Milicevic 1

Technical school of Krusevac, Serbia,

2

2

Grammar School of Krusevac, Serbia

ABSTRACT In this work we are going to present some experiments by which we have raised the pupils’ awareness about the problems of sustainable development and turn their attention to some of the main ecological, health and social threats of 21st century: climate changes and effects the Sun radiation has on our health. Educational system has an important role in the problem of sustainable development, and our experience proves that pupils can understand the mechanisms of climate changes which are caused by natural phenomena or by human activities, and it develops their awareness about the importance of protecting human environment in our everyday activities.

222

∏ PLASMA PHYSICS HYDRODYNAMIC MODEL OF SPATIO-TEMPORAL EVOLUTION OF TWOPLASMON DECAY D. R. Dimitrijevi ¶ and A. A. Maluckov Department of Physics, Faculty of Sciences and Mathematics, University of Ni_, P. O. Box 224, 18001 Ni £, Serbia ABSTRACT A hydrodynamic model of two-plasmon decay in a homogeneous plasma slab near the quarter-critical density is constructed in order to gain better insight into the spatio-temporal evolution of the daughter electron plasma waves in plasma in the course of the instability. The influence of laser and plasma parameters on the evolution of the amplitudes of the participating waves is discussed. The secondary coupling of two daughter electron plasma waves with an ion-acoustic wave is assumed to be the principal mechanism of saturation of the instability. The impact of the inherently nonresonant nature of this secondary coupling on the development of TPD is investigated and it is shown to significantly influence the electron plasma wave dynamics. Its inclusion leads to nonuniformity of the spatial profile of the instability and causes the burst-like pattern of the instability development, which should result in the burst-like hot-electron production in homogeneous plasma.

DETECTION OF GROUP OF SUPER FAST ELECTRONS IN HYDROGEN PLASMA FROM THE RATIO OF THE INTENSITY Of H 2 FULCHER · AND H SPECTRAL LINES

·

S.R.Mijovic, M.J.Vuceljic University of Montenegro, Faculty of Natural Science, Podgorica [email protected] ABSTRACT Spectroscopic method for the detection of fast electrons in weak ionized plasma, at low pressure, from the ratio of the intensity H2 Fulcher and H· spectral lines was proposed. Influence of the electron energy distribution functions with different electron groups to the intensity of the molecular and atomic hydrogen spectra were analyzed. First step at this processes is a calculation a ratio IH2/IH· dependence to the electron temperature Te for Maxwellian electron energy distribution function. Group of fast electrons was added to Maxwellian distribution according to experimental results. Influence on intensity ratio was analyzed in this situation. In next step group of super fast electron was added too. Both group of fast electrons at electron energy distribution function contributed a great deal to those ratios. On that way a sophisticated method of measurements electron energy distribution function by electrostatic probe is avoided.

223

STARK WIDTHS AND SHIFTS DEPENDENCE ON THE REST CORE CHARGE OF THE EMITTERS WITHIN ns-np TRANSITION ARRAYS Mara ‹éepanovi ¶1 and Jago £ Puri ¶2 1Faculty

of Natural Sciences, University of Montenegro, POB 211, 81000 Podgorica, Montenegro, 2Faculty of Physics, University of Belgrade, POB 368, 11001 Belgrade, Serbia

ABSTRACT Stark width and shift simultaneous dependence on the upper level ionization potential and rest core charge of the emitter has been evaluated and discussed. It has been verified that the found relations, connecting Stark broadening parameters with upper level ionization potential and rest core charge of the emitters for particular electron temperature and density, can be used for prediction of Stark line width and shift data in case of ions for which observed data, or more detailed calculations, are not yet available. Stark widths and shifts published data are used to demonstrate the existence of other kinds of regularities within similar spectra of different elements and their ionization stages. The emphasis is on the Stark parameter dependence on the upper level ionization potential and on the rest core charge for the lines from similar spectra of multiply charged ions. The found relations connecting Stark widths and shift parameters with upper level ionization potential, rest core charge and electron temperature were used for a prediction of new Stark broadening data, thus avoiding much more complicated procedures.

THE ANALYSIS OF BREAKDOWN VOLTAGE DISTRIBUTIONS IN NITROGEN AT 4 mbar J. R. ›ivkovi ¶-Andrejev #, J.P. Karamarkovi ¶*, M. K. Radovi ¶¨, ¤. A. Maluckov _ Faculty of Mechanical Engineering, University of Ni £, A. Medvedeva 14, 18000 Ni £, Serbia, of Civil Engineering and Architecture, University of Ni £, A. Medvedeva 14, 18000 Ni £, Serbia, ¨Faculty of Sciences and Mathematics, University of Ni £, PO Box 224 18001 Ni £, Serbia, _Technical Faculty in Bor, University of Belgrade, Vojske Jugoslavije 24, 19210 Bor, Serbia ABSTRACT *Faculty

The analysis of the breakdown voltage density distributions of the diode filled with nitrogen at 4 mbar pressure is presented in this paper. The tube has spherical iron electrodes of 10 mm diameter at a distance of 3 mm. A diode tube is made of molybdenum glass with inner diameter 5 cm and tube length 15 cm. The distributions are determined experimentally with the linearly rising voltage applied to the gas diode. The voltage increasing rate is determined in range of 1 up to 100 V/s. Every particular distribution is established on the base of the 1000 successive and independent measurements of the breakdown voltage under the identical experimentally conditions. These distributions are studied using the statistical instruments of reliability theory. The complement of cumulative distribution function is plotted and it is found that breakdown voltage obeys Weibull distribution. The density distribution functions obtained in fitting procedure are compared with experimentally obtained histograms. The dependence of the shape parameter of Weibull distribution on the voltage increasing rate is analyzed.

MONTE-CARLO ANALYSIS OF THE ACCURACY OF A NOVEL THOMSON SCATTERING LIDAR APPROACH TO MEASURING THE ELECTRON TEMPERATURE IN FUSION PLASMAS Tanja N. Dreischuh, Ljuan L. Gurdev, Dimitar V. Stoyanov Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko shosse, Sofia 1784, Bulgaria ABSTRACT The knowledge of the electron temperature Te and density ne profiles in the tokamak plasma is very important for understanding, characterizing and controlling the plasma processes. Therefore, these parameters need to be measured with a good spatial and temporal resolution. Because of the high characteristic temperatures in thermonuclear plasmas, from about 200 eV (~2x106 K) near the edge of the torus to 10-40 keV (1-4 x10 8 K) in the center, the only effective methods for sensing them turn out to be the contactless passive and active optical or microwave ones. Among these, the Thomson224

scattering-based lidar-type methods [1] are especially appropriate for simultaneous determination of Te and ne profiles in fusion plasmas. This diagnostic is in operation at JET now and is intended to be used in ITER. The approach used so far for electron temperature and pressure determination is based on log-linear or non-linear fit of the experimentally-obtained, relativistically-thermally-broadened lidar-return spectra to the corresponding theoretical expression. Recently we proposed and developed two novel approaches for determination of Te on the basis of an analysis of the relativistic Thomson scattering (TS) spectrum [2]. One of them is based on the unambiguous dependence of the “center-of-mass wavelength” of the lidar-return spectrum on Te while the second one uses the unambiguous temperature dependence of the ratio of the signal powers of two spectral regions. The potential accuracy of the proposed methods is estimated on the basis of the derived analytical expressions of the corresponding rms relative errors in the determination of Te [2]. The main aim of the present work is to analyze in detail the error in the determination of the electron temperature in tokamak plasmas by the approach based on the ratio of the signals from two wide spectral intervals, depending on the temperature itself and the signal-to-noise ratio (SNR) achieved. For this purpose Monte Carlo simulations of the temperature measurement process have been performed taking into account the photon flux measurement specificity, the bremsstrahlung contribution to the plasma light background and the Poisson noise effects. The characteristic parameters of the plasma and the TS lidar system used in the simulations are chosen to be close to those of JET tokamak and JET TS core lidar system. As a result we have obtained the authentic rms temperature-measurement error as a function of the electron temperature and the energy in the sensing laser pulse, conditioning the SNR. The results obtained confirm the analytical expressions in their region of validity, where the SNR is well above unity. The analysis of the results shows that at pulse energy of 0.6 J and sensing radiation wavelength of 694 nm the relative rms error is below 10% for Te between 2 keV and 12 keV; in this case, the mean SNR achieved is about 15-20. At higher pulse energy, of e.g. 6 J, the relative rms error is below 10% for temperatures between 1 keV and 40 keV. It is even below 5% for Te between 2 keV and 25 keV. Note that the relative rms error of the considered “power ratio” approach is comparable with the errors intrinsic to the “center-of-mass” approach and the fitting approach. So, this approach may be advantageous due to the possibility of using essentially simpler hardware consisting of only two receiving spectral channels. This work was funded jointly by the EURATOM/INRNE Fusion Association and by the Bulgarian National Science Fund under the project F-1511. References: [1] H. Salzmann et al., “The LIDAR Thomson scattering diagnostic on JET”, Rev. Sci. Instrum. 59, 1451 (1988). [2] Ljuan L. Gurdev, Tanja N. Dreischuh, Dimitar V. Stoyanov, Proceedings of SPIE 7027, 702711 (2008).

THE ANALYSIS OF BREAKDOWN VOLTAGE DISTRIBUTIONS IN NITROGEN AT 4 mbar J. R. ›ivkovi ¶-Andrejev #, J.P. Karamarkovi ¶*, M. K. Radovi ¶¨, ¤. A. Maluckov _ Faculty of Mechanical Engineering, University of Ni £, A. Medvedeva 14, 18000 Ni £, Serbia, of Civil Engineering and Architecture, University of Ni £, A. Medvedeva 14, 18000 Ni £, Serbia, ¨Faculty of Sciences and Mathematics, University of Ni £, PO Box 224 18001 Ni £, Serbia, _Technical Faculty in Bor, University of Belgrade, Vojske Jugoslavije 24, 19210 Bor, Serbia ABSTRACT *Faculty

The analysis of the breakdown voltage density distributions of the diode filled with nitrogen at 4 mbar pressure is presented in this paper. The tube has spherical iron electrodes of 10 mm diameter at a distance of 3 mm. A diode tube is made of molybdenum glass with inner diameter 5 cm and tube length 15 cm. The distributions are determined experimentally with the linearly rising voltage applied to the gas diode. The voltage increasing rate is determined in range of 1 up to 100 V/s. Every particular distribution is established on the base of the 1000 successive and independent measurements of the breakdown voltage under the identical experimentally conditions. These distributions are studied using the statistical instruments of reliability theory. The complement of cumulative distribution function is plotted and it is found that breakdown voltage obeys Weibull distribution. The density distribution functions obtained in fitting procedure are compared with experimentally obtained histograms. The dependence of the shape parameter of Weibull distribution on the voltage increasing rate is analyzed.

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CONTENTS

INVITED TALKS – THE PHYSICS OF ENERGY TECHNOLOGIES .........................................................................................................................................5 – THE GREENHOUSE GAS REGIONAL INVENTORY PROTOCOL .........................................................................................................5 – CARBON BASED NANOSTRUCTURES SYNTHESIS AND CHARACTERIZATION...........................................................................6 – ENERGY AND ENVIRONMENT IN URBAN AREAS................................................................................................................................6 – FRONTIERS OF R & D IN PHOTOVOLTAIC MATERIALS AND DEVICES.........................................................................................7 – CC CALCULATIONS ON SOME NUCLEI WITH SRM..............................................................................................................................7 – CRITICAL PHENOMENA AND FINITE-SIZE SCALING,CRITICAL BEHAVIOR OF CONFINED SYSTEMS ................................8 – LHC – EXPECTATIONS AND REALITY.....................................................................................................................................................9 – THE STRAGE FRIENDSHIP OF PAULI AND JUNG, WHEN PHYSICS MET PSYCHOLOGY .........................................................9 – PHYSICAL PROPERTIES OF La-Pb-Mn PEROVSKITES ........................................................................................................................9 – THE VOYAGER INTERSTELLAR MISSION: CROSSINGS OF THE HELIOSPHERIC TERMINATION SHOCK IN 2004 (V1) AND 2007 (V2) ........................................................................................................................................................10 – NOVEL PROCESSES IN MATER-WAVE OPTICS....................................................................................................................................10 – ENTROPY, A UNIFYING CONCER............................................................................................................................................................11 – INFLUENCE OF COLLISIONS WITH CHARGED PARTICLES ON ASTRONOMICAL SPECTRA ..................................................11 – TURKISH ACCELERATOR CENTER (TAC) PROJECT...........................................................................................................................12 – TITANIA NANOSTRUCTURES FROM FIRST-PRINCIPLES CALCULATIONS FOR PHOTOCATALYTIC AND PHOTOVOLTAIC APPLICATIONS ....................................................................................................12 – THERMOELECTRIC MATERIALS AND APPLICATIONS ON THE RECOVERY OF WASTE HEAT ENERGY ............................13 – HISTORY OF PHYSICS - A CHALLENGE TO THE PHYSICS COMMYNITY...................................................................................14

A NUCLEAR PHYSICS – A COMPREHENSIVE STUDY ON NATURAL GAMMA RADIOACTIVITY LEVELS AND ASSOCIATED DOSE RATES FROM SANDS AND ROCKS IN RIZE, TURKEY ........................................................................15 – CRITICALITY CALCULATIONS ON A CYLONDER FISSION REACTOR FUELLED WITH URANIUM .......................................16 – DESCRIPSTION OF MIXED-MODE DYNAMICS WITH SYMPLECTIE INTERACTING VECTOR BOSON MODEL ...........................................................................................................................................................................16 – SIMULTANEOUS DESCRIPTION OF EVEN-EVEN, ODD-MASS AND ODD-ODD NUCLEAR SPEECTRA ..................................17 – GIANT DIPOLE RESPONCE FUNCTION OF NEUTRON RICH NUCLEI .............................................................................................17 – ON THE NUCLEAR TWO-NEUTRINO DECAY MODE..........................................................................................................................17 – MICRO-SR-XRF STUDIES FOR ARCHAEOLOGICAL GOLD IDENTIFICATION – THE CASE OF CARPATHIAN GOLD AND OF DACIAN BRACELETS ...............................................................................................17 – SOME APPLICATIONS OF X-RAY BASED ELEMENTAL ANALYSIS METHODS FOR ROMANIAN GOLD MINERALS STUDIES .......................................................................................................................................19 – MESUREMENT OF TEMPERATURE IN SPALLATION REACTION ....................................................................................................19 – ELECTRIC DIPOLE MIXING IN PHOTON INDUSED INNER-SHELL MAGNETIC QUADRUPOLE TRANSITIONS ...................................................................................................................................................................20 – THE INVESTIGATION OF 115 IN NUCLEUS AT CLIC-LHC BASED FEL NUCLEUS COLLIDER .................................................20 – A DECONVOLUTION TECHNIQUE FOR MEASURING LOW-ENERGY BETA ACTIVITY IN SAMPLES CONTAMINATED WITH HIGH-ENERGY BETA IMPURITIES .............................................................................................................................................20 – IN-SITU GAMMA SPECTROMETRY AND DOSE RATE MEASUREMENTS IN EMERGENCY SITUATIONS - THE RESULTS OF THE INR-PITESTI TO AN INTERNATIONAL INTERCOMPARISON EXERCISE .......................................................................21 – DETECTION OF LANDMINES BY NEUTRON BACKSCATTERING ...................................................................................................21 – DETERMINATION OF NATURAL RADIOACTIVITIES AROUND THE SALT LAKE IN TURKEY................................................22 – CONTRIBUTIONS REGARDING THE AIRCRAFT NUCLEAR PROPULSION ....................................................................................22 – CHARACTERIZATION STUDIES OF A RADIOACTIVE WASTE DRUM USING HIGH RESOLUTION GAMMA SPECTROMETRIC SYSTEMS .....................................................................................................................................................................22

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B PARTICLE PHYSICS – USE OF ONE-RANGE ADDITION THEOREMS IN CALCULATION OF MULTICENTER NUCLEAR ATTRACTION INTEGRALS OVER SLATER TYPE ORBITALS .......................................................................................................................................23 – USE OF SYMMETRICAL ONE-RANGE ADDITION THEOREMS IN CALCULATION OF ONE-ELECTRON MULTICENTER INTEGRALS OF SLATER TYPE ORBITALS AND COULOMB-YUKAWA LIKE CORRELATED INTERACTION POTENTIALS WITH INTEGER AND NONINTEGER INDICES ...................................................23 – GROUND STATE OF INTERACTING MANY BOSON SYSTEMS: AN APPROACH BASED ON NATURAL ORBITALS ...............................................................................................................................24 – ANOTHER EVALUATION OF THE S-PARAMETER FOR WALKING TECHNICOLOR...................................................................24 – SINGLE TOP PRODUCTION, NLO QCD CORRECTIONS FOR t-CHANNEL SINGLE TOP PRODUCTION..................................25 – MEASUREMENT OF THE PROTON STRUCTURE FUNCTION FL(x,Q2) WITH THE H1 EXPERIMENT......................................25 – MEASUREMENT OF PROTON STRUCTURE AND PARTON DENSITY FUNCTIONS FROM HERA .............................................25 – THE CMS RPC SYSTEM OVERVIEW .......................................................................................................................................................26 – FORWARD REGION STUDIES FOR ILC. ..................................................................................................................................................26 – DISTRIBUTED DATA ACQUISITION AND CONTROL SYSTEM FOR THE CMS PRESHOWER DETECTOR.............................26 – COSMIC RADIATION INTENSITY MEASUREMENTS USING TL DOSIMETERS AT VARIOUS MOUNTAIN ALTITUDES ....................................................................................................................................................26 – HEAVY FLAVOR IDENTIFICATION USING MULTIVARIATE ANALYSIS AT H1...................................................................................27 – RARE KAON DECAYS AT CERN SPS .......................................................................................................................................................27 –THE ALICE EXPERIMENT AT CERN .......................................................................................................................................................27 – MEASUREMENT OF THE PT SPECTRA OF DELTA BARYON RESONANCES IN C+C COLLISIONS AT 4.2 GeV/c PER NUCLEON ................................................................................................................................28 – MEASUREMENT OF THE NEUTRAL CURRENT DEEP INELASTIC SCATTERING CROSS SECTION AT LOW AND MEDIUM Q2 USING H1 DATA .........................................................................................................................................28

C ASTRONOMY & ASTROPHYSICS – CHAOTIC ORBITS IN A 3D BL-LACERTAE OBJECT............................................................................................................................29 – A STUDY ON INTERSTELLAR COMMUNICATION: THE PREREQUISITE FOR INTERSTELLAR EXPANSION ...........................................................................................................................................................29 – STUDY OF THE SOLAR WIND PARAMETERSDURING THE 23RD SOLAR CIRCLE ........................................................................30 – A SIGHT ON THE VARIATION OF SPECTRAL PARAMETERS IN GRB IS THE SLOPE VARIATION AN EFFECT OF OBSERVATION BANDS? .............................................................................................30 – PRIMARY ENERGY SPEECTRUM AS RECONSTRUCTED BY KASCADE-GRANDE FROM S(500) MEASURMENTS .............31 – TYPE III RADIO BURSTS OBSERVED WITH RADIO SPECTROGRAPH h ARTEMIS IV WITHIN THE INTENSE ACTIVE PERIOD OCTOBER - NOVEBER 2003 ...........................................................................................31 – THE ANTIKYTHERA MECHANISM, AN ANCIENT ASTRONOMICAL INSTRUMENT AND COMPUTER.................................32 – THE CONTRIBUTION OF THE ABSORPTION PROCESS TO THE OPACITY OF DB WHITE DWART ATMOSPHERES IN UV AND VUN REGIONS...........................................................................................................................................32 – UNDERSTANDING KAPPA DISTRIBUTIONS IN SPACE PLASMAS USING TSALLIS STATISTICAL MECHANICS ..........................................................................................................................................33 – DYNAMIC OF STATIONARY STATES OUT OF EQUILIBRIUM IN SPACE PLASMAS ....................................................................33 – CMES MAIN PROPERTIES VARIATION DURING THE DIFFERENT PHASES OF THE SOLAR CYCLE 23 ...............................33 – THE ANTIKYTHERA MECHANISM: AN EDUCATIONAL TOOL TO ATTRACT THE GENERAL PUBLIC INTO SCIENCE AND TECHNOLOGY ..........................................................................................................34 – TRANSFORMATIONS OF CONSTANTLY ACCELERATING REFERENCE FRAME AND INERTIAL REFERENCE FRAMES 35

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D SOLID STATE PHYSICS – QUANTUM HALL EFFECT FROM Von KLITZING to QUANTUM COMPUTERS ...........................................................................36 – CHARGE TRANSFER MECHANISM ALONG THE DNA DOUBLE HELIX .......................................................................................37 – THE INVESTIGATION OF STRUCTURAL, OPTICAL AND ELECTRICAL PROPERTIES OF CDO THIN FILMS GROWN BY SILAR METHOD AND DEVICE PARAMETERS OF CD/CDO/N-SI/AU-SB STRUCTURE.................................................................37 – DEFORMATION BEHAVIOR OF NANOCRYSTALLINE Al ALLOY, PROCESSED BY SEVERE PLASTIC DEFORMATION .........................................................................................................................38 – ELEMENTARY EXCITATIONS IN FERROMAGNETIC SEMICONDUCTOR SUPERLATTICE IN THE NARROW-BAND LIMIT ................................................................................................................................................................39 – MAGNETIC PROPERTIES FexPt1-x ALLOYS..........................................................................................................................................39 – THE TEMPERATURE DEPENDENCE OF CURRENT –VOLTAGE CHARAACTERISTICS OF Zn/ZnSe/n-Si/AuSb STRUCTURE ...........................................................................................................................................................40 – MIXING OF FRENKEL AND CHARGE-TRANSFER EXCITIONS IN ONE-COMPONENT MOLECULAR CRYSTALS..................................................................................................................................40 – FLEXOELECTRIC PROPERTIES OF BANANA-LIKE NEMATIC LIQUID CRYSTALS...................................................................41 – QUARTZ CRYSTAL MICROBALANCE (QCM): AN ALTERNATIVE ANALYTICAL METOD FOR INVESTIGATION IN REALTIME OF LIQUID PROPERTIES .................................................................................................................................................................41 – CORRELATION BETWEEN THICKNESS, CONDUCTIVITY AND THERMAL DEGRADATION MECHANISMS OF PEDOT:PSS FILMS .......................................................................................................................42 – ELECTRON-PHONON INTERACTION IN GRAPHENE ........................................................................................................................43 – LASER PHOTOTHERMAL ANALYSIS OF MAGNETOELECTRIC MATERIALS..............................................................................43 – TEMPERATURE DEPENDENT DIELECTRIC PROPERTIES OF Au/ POLYVINYL ALCOHOL (Co, Ni-Doped)/n-Si SCHOTTKY DIODES ................................................................................................................................................44 – TEMPERATURE DEPENDENT CURRENT-VOLTAGE (I-V) CHARACTERISTICS of Au/n-Si (111) SCHOTTKY BARRIER DIODES (SBDs) WITH POLYVINYL ALCOHOL (PVA) INTEFACIAL LAYER................................................................................44 – DIELECTRIC PROPERTIES AND ELECTRICAL CONDUCTIVITY OFAu/ POLYVINYL ALCHOOL (Co, Ni-Doped)/n-Si SCHOTTKY DIODES .................................................................................................................................................44 – NEUTRON DIFFRACTION INVESTIGATION OF Pb0.5La0.5FeO3 ........................................................................................................45 – VIBRATIONAL PPROPERTIES OF SILVER-DOPED ARSENIC CHALCOGENIDE BULK GLASSES ...........................................46 – MODELING OF INDENTATION OF FIBER REINFORCED MATERIALS USING SPHERICAL INDENTERS............................46 – ADSORPTION, DESORPTION AND DIFFUSION OF k-mers ON A ONE-DIMENSIONAL LATTICE.............................................47 – LOW-DIMENSIONAL CARRIERS UNDER MAGNETIC FIELD: NOVEL PHENOMENA.................................................................47 – PHONONS IN MULTI-WALL MS2 (M=MO,W) NANOTUBES ...............................................................................................................48 – DERIVING WANNIER-STARK LADDERS OF RESONANCES FOR ELECTRONS ON COUPLED CHAINS ..................................48 – STRUCTURAL INVESTIGATION OF Tm3+ DOPED (1-x)TeO2-(x)ZnO-5TiO2 OPTICAL GLASSES ...............................................48 – DIFFRACTION FROM QUASI ONE-DIMENSIONAL CRYSTALS AND NANOTUBES......................................................................49 – INVESTIGATION OF THE DEBYE-WALLER FACTOR OF CRYSTALS USING BINOMIAL COEFFICIENTS AND INCOMPLETE GAMMA FUNCTIONS ...............................................................................................................49 – PREPARATION OF Co, Mn, Nd DOPED SiO2 THIN FILMS AND INVESTIGATING THE MICROSTRUCTURAL PROPOERTIES ...................................................................................................50 – STRUCTURE AND PROPERTIES INVESTIGATION OF MIXED OXIDES YCr1-xFexO3 (0