Pub Date : 2015-01-01DOI: 10.13189/UJPA.2015.090301
Sorry Abdissa, G. Meheretu, S. Gebremichael
We studied the interfacial layer effects on the enhancement factor of local field and the optical induced bistability for small spherical metal/dielectric in linear host matrices. It is calculated the interfacial layer effect analytically and numerically on the enhancement factor of local field and the cubic equation of the optical induced bistability of the composite material. We have shown the parameters of the interfacial layer and calculated. We take positive, zero, and negative values which represents dielectric like, no interfacial, and metal like, respectively for the pure metal case. In the case of metal/dielectric for which we consider the interfacial layer particle the above mentioned properties are reversed so that it will be positive to realize the metal like properties of the interfacial layer. The analytical and numerical results show that the enhancement factor of local field is extremely enhanced and the optical induced bistability increased its domain.
{"title":"Interfacial Layer Effects on the Enhancement Factor of Local Field and Optical Induced Bistability in Small Spherical Metal/Dielectric Composites","authors":"Sorry Abdissa, G. Meheretu, S. Gebremichael","doi":"10.13189/UJPA.2015.090301","DOIUrl":"https://doi.org/10.13189/UJPA.2015.090301","url":null,"abstract":"We studied the interfacial layer effects on the enhancement factor of local field and the optical induced bistability for small spherical metal/dielectric in linear host matrices. It is calculated the interfacial layer effect analytically and numerically on the enhancement factor of local field and the cubic equation of the optical induced bistability of the composite material. We have shown the parameters of the interfacial layer and calculated. We take positive, zero, and negative values which represents dielectric like, no interfacial, and metal like, respectively for the pure metal case. In the case of metal/dielectric for which we consider the interfacial layer particle the above mentioned properties are reversed so that it will be positive to realize the metal like properties of the interfacial layer. The analytical and numerical results show that the enhancement factor of local field is extremely enhanced and the optical induced bistability increased its domain.","PeriodicalId":23443,"journal":{"name":"Universal Journal of Physics and Application","volume":"66 1","pages":"135-140"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90174399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.13189/UJPA.2015.090602
Maifi Lyes, Kerbache Tahar, Hioual Ouided
Hybrid thermal/photovoltaic systems associating a solar concentrator with a heat exchanger are an effective way to improve solar energy conversion yield. We present here an analysis of the effect of the mass flow rates in such a collector. A numerical simulation of the performance of the thermal/photovoltaic sensor with a heat exchanger including fins attached to the absorber and using air as a coolant is presented. A thorough analysis of the influence of the mass flow rate on the efficiency and the working of a thermal/photovoltaic collector is presented. The analysis is made using the equations of the components of heat transfer cascade into a matrix of four unknown's which are the glass , cells, fluid and insulation plate temperature. This matrix is solved by the fixed point method and Gauss-Seidel, at the permanent regime. Results show that the overall conversion efficiency of the system is increasing from 27% to 65%, and the cell temperatures decreasing from 345°K to 335°K when mass flow rates varies from 0.02 kg/s to 0.1 kg/s.
{"title":"Study of the Mass Flow Rates on the Efficiency of Hybrid Thermal / Photvoltaique Sensor","authors":"Maifi Lyes, Kerbache Tahar, Hioual Ouided","doi":"10.13189/UJPA.2015.090602","DOIUrl":"https://doi.org/10.13189/UJPA.2015.090602","url":null,"abstract":"Hybrid thermal/photovoltaic systems associating a solar concentrator with a heat exchanger are an effective way to improve solar energy conversion yield. We present here an analysis of the effect of the mass flow rates in such a collector. A numerical simulation of the performance of the thermal/photovoltaic sensor with a heat exchanger including fins attached to the absorber and using air as a coolant is presented. A thorough analysis of the influence of the mass flow rate on the efficiency and the working of a thermal/photovoltaic collector is presented. The analysis is made using the equations of the components of heat transfer cascade into a matrix of four unknown's which are the glass , cells, fluid and insulation plate temperature. This matrix is solved by the fixed point method and Gauss-Seidel, at the permanent regime. Results show that the overall conversion efficiency of the system is increasing from 27% to 65%, and the cell temperatures decreasing from 345°K to 335°K when mass flow rates varies from 0.02 kg/s to 0.1 kg/s.","PeriodicalId":23443,"journal":{"name":"Universal Journal of Physics and Application","volume":"1 1","pages":"244-250"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86413161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.13189/UJPA.2015.090202
L. K. Abhilashi, P. Sharma, R. Vaish, P. Sharma
Sn13Se87-xSbx (x = 0, 3, 6, 9, 12) glassy system is synthesized by melt quench technique. This glassy system has been studied for various physical parameters viz. coordination number, lone pair of electrons, number of constraints, bond energy, heat of atomization, glass transition temperature, cohesive energy, band gap and mean bond energy. From the physical analysis it is generalized that the average number of constraints, average heat of atomization, mean bond energy, glass transition temperature and cohesive energy are found to increase whereas numbers of lone pair of electrons calculated are found to decrease with the increase in the antimony content in the composition of the alloy. The increase in glass transition temperature has been explicated on the basis of accumulation of antimony atoms in selenium chain.
{"title":"Effect of Compositional Dependence on the Physical Properties of Sn-Se-Sb Chalcogenide Glasses","authors":"L. K. Abhilashi, P. Sharma, R. Vaish, P. Sharma","doi":"10.13189/UJPA.2015.090202","DOIUrl":"https://doi.org/10.13189/UJPA.2015.090202","url":null,"abstract":"Sn13Se87-xSbx (x = 0, 3, 6, 9, 12) glassy system is synthesized by melt quench technique. This glassy system has been studied for various physical parameters viz. coordination number, lone pair of electrons, number of constraints, bond energy, heat of atomization, glass transition temperature, cohesive energy, band gap and mean bond energy. From the physical analysis it is generalized that the average number of constraints, average heat of atomization, mean bond energy, glass transition temperature and cohesive energy are found to increase whereas numbers of lone pair of electrons calculated are found to decrease with the increase in the antimony content in the composition of the alloy. The increase in glass transition temperature has been explicated on the basis of accumulation of antimony atoms in selenium chain.","PeriodicalId":23443,"journal":{"name":"Universal Journal of Physics and Application","volume":"26 1","pages":"58-63"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84666207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.13189/ujpa.2015.090502
Yan Rongxin, Qi Lei
The leaks are very dangerous for astronauts on orbit spacecraft. So the techniques of leak testing have been developed with acoustics method. The produce of pneumatic sound source of the leak and the gas leak detection technology based on acoustic sensor array are studied. The detection distance and direction of array are verified by the experiments. In the leak, the sound power of the gas jet is related to the diameter and length of the leak. When the measuring distance is constant, the average error of the experiment is relative to angle between leak and sensor array. When the relative angle is constant, with the increase of the distance, orientation error increases slightly, but is less than ±5°.
{"title":"A Gas Leak and Structural Damage Detector for Spacecraft on-orbit Based on Two-staged Acoustic Sensors Array","authors":"Yan Rongxin, Qi Lei","doi":"10.13189/ujpa.2015.090502","DOIUrl":"https://doi.org/10.13189/ujpa.2015.090502","url":null,"abstract":"The leaks are very dangerous for astronauts on orbit spacecraft. So the techniques of leak testing have been developed with acoustics method. The produce of pneumatic sound source of the leak and the gas leak detection technology based on acoustic sensor array are studied. The detection distance and direction of array are verified by the experiments. In the leak, the sound power of the gas jet is related to the diameter and length of the leak. When the measuring distance is constant, the average error of the experiment is relative to angle between leak and sensor array. When the relative angle is constant, with the increase of the distance, orientation error increases slightly, but is less than ±5°.","PeriodicalId":23443,"journal":{"name":"Universal Journal of Physics and Application","volume":"1 1","pages":"212-215"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89367418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.13189/UJPA.2015.090304
L. Deleidi, M. Greselin
In this paper we analyze the formal and conceptual steps made by Ettore Majorana in a wide set of unpublished (handwritten) manuscripts (Quaderni, Fascicoli, Volumetti) written in later 20's and earlier 30's where, starting from the Dirac equation for spin-1/2 particles, he developed quantum relativistic wave equations for different (integer and half-integer) spins. In such a way Majorana obtained a Dirac-like equation for the photon and an infinite component quantum field theory for particles of any spin, thus anticipating the modern supersymmetry and string theories.
{"title":"About Majorana's Unpublished Manuscripts on Relativistic Quantum Theory for Particles of Any Spin","authors":"L. Deleidi, M. Greselin","doi":"10.13189/UJPA.2015.090304","DOIUrl":"https://doi.org/10.13189/UJPA.2015.090304","url":null,"abstract":"In this paper we analyze the formal and conceptual steps made by Ettore Majorana in a wide set of unpublished (handwritten) manuscripts (Quaderni, Fascicoli, Volumetti) written in later 20's and earlier 30's where, starting from the Dirac equation for spin-1/2 particles, he developed quantum relativistic wave equations for different (integer and half-integer) spins. In such a way Majorana obtained a Dirac-like equation for the photon and an infinite component quantum field theory for particles of any spin, thus anticipating the modern supersymmetry and string theories.","PeriodicalId":23443,"journal":{"name":"Universal Journal of Physics and Application","volume":"15 12 1","pages":"168-171"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86965163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.13189/UJPA.2015.090405
D. Morozov, S. Vafin, A. A. Mavrin
The problem of the thermal equilibrium and density limit in tokamak-reactor are analyzed. The empirical Greenwald criterion determining the critical plasma density may be exceeded in tokamaks with auxiliary heating. One may expect that the fusion power may increase the critical plasma density. The thermal balance in tokamak-reactors is discussed. The critical density is defined by the equality of heating (auxiliary plus fusion) power and radiation losses at the plasma edge. The influence of fusion power input as well as auxiliary heating on the critical density is studied. The analytic model is based on some simplifying assumptions. The auxiliary heating as well as the thermonuclear one is assumed to be localized at the center of the plasma column. The slab geometry is assumed for simplicity. It is shown that the critical density rises up increasing the fusion output drastically using the feedback control.
{"title":"Thermal Equilibrium and Density Limit in Tokamak-Reactor","authors":"D. Morozov, S. Vafin, A. A. Mavrin","doi":"10.13189/UJPA.2015.090405","DOIUrl":"https://doi.org/10.13189/UJPA.2015.090405","url":null,"abstract":"The problem of the thermal equilibrium and density limit in tokamak-reactor are analyzed. The empirical Greenwald criterion determining the critical plasma density may be exceeded in tokamaks with auxiliary heating. One may expect that the fusion power may increase the critical plasma density. The thermal balance in tokamak-reactors is discussed. The critical density is defined by the equality of heating (auxiliary plus fusion) power and radiation losses at the plasma edge. The influence of fusion power input as well as auxiliary heating on the critical density is studied. The analytic model is based on some simplifying assumptions. The auxiliary heating as well as the thermonuclear one is assumed to be localized at the center of the plasma column. The slab geometry is assumed for simplicity. It is shown that the critical density rises up increasing the fusion output drastically using the feedback control.","PeriodicalId":23443,"journal":{"name":"Universal Journal of Physics and Application","volume":"46 1","pages":"201-205"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72851068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.13189/UJPA.2015.090504
V. Belyi, N. Kazak, P. A. Khilo, E. Petrova, N. Khilo
The peculiarities have been studied of acoustooptic (AO) diffraction of quasi- nondiffracting vector Bessel light beams (BLB) on the ultrasound waves in optical gyrotropic cubic crystals. The system of coupled equations describing the process of acoustooptic interaction is solved, diffraction efficiency has been calculated. The mathematical description of AO interaction, which differs from the similar description for the plane optical waves means of two types of synchronism, is conducted. It is shown that besides the usual longitudinal synchronism realized at the equality of phase velocities transmitted and diffracted waves, for Bessel beams it is also necessary to perform the so-called transverse synchronism. It is related with the fact, that Bessel beams with differing cone angles have different spatial structure and, consequently, various values of overlap integral with the input beam. The possibility has been investigated of transformation of the order of phase dislocation of Bessel beams wave front due to AO diffraction. It is proposed to use the process of acoustooptic diffraction in gyrotropic cubic crystals as a method for dynamic manipulation of polarization state of output Bessel beam, particularly for transformation of left- to right (and vice versa) polarization states.
{"title":"Peculiarities of Acoustooptic Transformation of Bessel Light Beams in Gyrotropic Crystals (","authors":"V. Belyi, N. Kazak, P. A. Khilo, E. Petrova, N. Khilo","doi":"10.13189/UJPA.2015.090504","DOIUrl":"https://doi.org/10.13189/UJPA.2015.090504","url":null,"abstract":"The peculiarities have been studied of acoustooptic (AO) diffraction of quasi- nondiffracting vector Bessel light beams (BLB) on the ultrasound waves in optical gyrotropic cubic crystals. The system of coupled equations describing the process of acoustooptic interaction is solved, diffraction efficiency has been calculated. The mathematical description of AO interaction, which differs from the similar description for the plane optical waves means of two types of synchronism, is conducted. It is shown that besides the usual longitudinal synchronism realized at the equality of phase velocities transmitted and diffracted waves, for Bessel beams it is also necessary to perform the so-called transverse synchronism. It is related with the fact, that Bessel beams with differing cone angles have different spatial structure and, consequently, various values of overlap integral with the input beam. The possibility has been investigated of transformation of the order of phase dislocation of Bessel beams wave front due to AO diffraction. It is proposed to use the process of acoustooptic diffraction in gyrotropic cubic crystals as a method for dynamic manipulation of polarization state of output Bessel beam, particularly for transformation of left- to right (and vice versa) polarization states.","PeriodicalId":23443,"journal":{"name":"Universal Journal of Physics and Application","volume":"34 1","pages":"226-230"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84079591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.13189/UJPA.2015.090603
Giménez Lorente Araceli
The attractor-repeller pairs are binary systems which are stable systems in termo-dynamic equilibrium, and one of the leaders we have in Nature to understand Tornadoes. A mathematical model of a tornado is presented, within a model of chaos theory, where two complementary fractals are combined to understand this natural phenomenon. It is a thermodynamic state where the wind formed by warm air rises (the repeller) while the swirling cold (attractor) wind descends joining together and creating a tornado, which is an equilibrium system. The mathematical modeling we present here is based on algorithms and it has been performed with Matlab code.
{"title":"Simulation of a Tornadoes as a Particular Case of an Attractor-repeller Pairs","authors":"Giménez Lorente Araceli","doi":"10.13189/UJPA.2015.090603","DOIUrl":"https://doi.org/10.13189/UJPA.2015.090603","url":null,"abstract":"The attractor-repeller pairs are binary systems which are stable systems in termo-dynamic equilibrium, and one of the leaders we have in Nature to understand Tornadoes. A mathematical model of a tornado is presented, within a model of chaos theory, where two complementary fractals are combined to understand this natural phenomenon. It is a thermodynamic state where the wind formed by warm air rises (the repeller) while the swirling cold (attractor) wind descends joining together and creating a tornado, which is an equilibrium system. The mathematical modeling we present here is based on algorithms and it has been performed with Matlab code.","PeriodicalId":23443,"journal":{"name":"Universal Journal of Physics and Application","volume":"37 1","pages":"251-257"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72631083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.13189/UJPA.2015.090402
V. Fedirko
The paper reports on theoretical estimation for electron spectra of free-standing graphene monolayer in presence of a rectangular quantum well. We have shown that 1D quasi-localized states localized mainly in the quantum well may exist, forming a peculiar quantum "rod" in a grapheme monolayer. Conventional hole tunneling through the quantum well is also described in addition to Klein tunneling usually considered in such structure.
{"title":"Graphene Electron States in a Quantum Well","authors":"V. Fedirko","doi":"10.13189/UJPA.2015.090402","DOIUrl":"https://doi.org/10.13189/UJPA.2015.090402","url":null,"abstract":"The paper reports on theoretical estimation for electron spectra of free-standing graphene monolayer in presence of a rectangular quantum well. We have shown that 1D quasi-localized states localized mainly in the quantum well may exist, forming a peculiar quantum \"rod\" in a grapheme monolayer. Conventional hole tunneling through the quantum well is also described in addition to Klein tunneling usually considered in such structure.","PeriodicalId":23443,"journal":{"name":"Universal Journal of Physics and Application","volume":"4 3 1","pages":"175-181"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78397338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.13189/UJPA.2015.090501
V. Fedirko
The paper reports on theoretical study of electron states for a quantum dot in a graphene monolayer. Discrete energy spectrum of quasiparticles inside the quantum dot is found. Energy levels and corresponding quasiparticle resonant wave functions are obtained, which allow calculating the local density of states inside the quantum dot. Some experimental results recently released are referred.
{"title":"Quantum Dots in Graphene","authors":"V. Fedirko","doi":"10.13189/UJPA.2015.090501","DOIUrl":"https://doi.org/10.13189/UJPA.2015.090501","url":null,"abstract":"The paper reports on theoretical study of electron states for a quantum dot in a graphene monolayer. Discrete energy spectrum of quasiparticles inside the quantum dot is found. Energy levels and corresponding quasiparticle resonant wave functions are obtained, which allow calculating the local density of states inside the quantum dot. Some experimental results recently released are referred.","PeriodicalId":23443,"journal":{"name":"Universal Journal of Physics and Application","volume":"5 1","pages":"207-211"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79133926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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