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2017

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Articles 10801 - 10830 of 11102

Full-Text Articles in Physical Sciences and Mathematics

Perturbative Construction Of The Two-Dimensional O(N) Nonlinear Sigma Model With Erg, Beki̇r Can Lütfüoğlu, Hidenori Sonoda Jan 2017

Perturbative Construction Of The Two-Dimensional O(N) Nonlinear Sigma Model With Erg, Beki̇r Can Lütfüoğlu, Hidenori Sonoda

Turkish Journal of Physics

We use the exact renormalization group (ERG) perturbatively to construct the Wilson action for the two-dimensional O(N) nonlinear sigma model (NLSM). The construction amounts to regularization of a nonlinear symmetry with a momentum cutoff. We find out that the model is parameterized by three functions. We show how to tune them by imposing the Ward--Takahashi (WT) identity. We construct two composite operators that generate infinitesimal change of the coupling constant and the renormalization of the scalar fields. Finally we show how the beta functions and the anomalous dimensions arise in the model up to 1-loop.

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Decomposition Of The Absorbed Dose By Let In Tissue-Equivalent Materials Within The Shield-Hit Transport Code, Nikolai Sobolevsky, Alexander Botvina, Ni̇hal Büyükçi̇zmeci̇, Ayşegül Kaya, Ludmila Latysheva, Riza Oğul Jan 2017

Decomposition Of The Absorbed Dose By Let In Tissue-Equivalent Materials Within The Shield-Hit Transport Code, Nikolai Sobolevsky, Alexander Botvina, Ni̇hal Büyükçi̇zmeci̇, Ayşegül Kaya, Ludmila Latysheva, Riza Oğul

Turkish Journal of Physics

The SHIELD-HIT transport code, in several versions, has been used for modeling the interaction of therapeutic beams of light nuclei with tissue-equivalent materials for a long time. All versions of the code include the useful option of decomposition of the absorbed dose by the linear energy transfer (LET), but this option has not been described and published to date. In this work the procedure of decomposition of the absorbed dose by LET is described and illustrated by using the decomposition of the Bragg curve in a water phantom, irradiated by beams of protons, alpha particles, and ions of lithium and …

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Investigation Of Binary Co$_{2}$X (X = In, Si, Sb, Sn, Ga) Half-Heusler Alloys, Adewumi Isaac Popoola Jan 2017

Investigation Of Binary Co$_{2}$X (X = In, Si, Sb, Sn, Ga) Half-Heusler Alloys, Adewumi Isaac Popoola

Turkish Journal of Physics

The electronic structure and mechanical properties of some cobalt-based binary half-Heusler alloys Co$_{2}$X (X = In, Si, Sb, Sn, Ga) have been investigated using the density functional theory approach. The site preference by cobalt and X is similar to the traditional half-Heusler structure. The results showed that Co$_{2}$Si is not a half-metal but rather an n-type degenerate semiconductor. The compounds Co$_{2}$Ga, Co$_{2}$Sb, and Co$_{2}$Sn are thermodynamically unstable and Co$_{2}$In is elastically unstable. With much care given to the lattice size, half metallicity is readily predicted in Co$_{2}$In, Co$_{2}$Ga, Co$_{2}$Sn, and Co$_{2}$Sb. All the compounds showed directional bonding and they should …

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Higher-Dimensional Dust Collapse In F(R) Gravity, Zahid Ahmad, Muhammad Shoaib Khan Jan 2017

Higher-Dimensional Dust Collapse In F(R) Gravity, Zahid Ahmad, Muhammad Shoaib Khan

Turkish Journal of Physics

The $n+2$-dimensional gravitational collapse of pressureless fluid is investigated in metric $f(R)$ gravity. Matching conditions are derived by taking the $n+2$-dimensional Friedmann-Robertson-Walker (FRW) metric as interior spacetime and the $n+2$-dimensional Schwarzschild metric as exterior spacetime. In the analysis of the solution of field equations, the scalar curvature is assumed to be a constant. It is observed that the scalar curvature constant term $f(R_{0})$ slows the collapse.

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Effect Of Pu Content On Uncertainty In Reactor Parameters Due To Use Of No Temperature Gradient In (U-Pu)O$_{2}$ Fuels, Mehmet Türkmen Jan 2017

Effect Of Pu Content On Uncertainty In Reactor Parameters Due To Use Of No Temperature Gradient In (U-Pu)O$_{2}$ Fuels, Mehmet Türkmen

Turkish Journal of Physics

Radial temperature distribution in a fuel rod is a parabolic function. Neutronics calculations are in general performed over a volume-averaged temperature by ignoring this distribution. Such an assumption results in an uncertainty in reactor design parameters. In this study, the magnitude of this uncertainty is estimated by solving the heat equation with a temperature-dependent conductivity coefficient coupled with a reactor physics code. The effect of radial fuel temperature distribution is investigated by representing the fuel region as multiregional. Uncertainty is investigated for various Pu contents of (U-Pu)O$_{2}$ fuel, a mix of depleted U and reactor-grade Pu. The effect of Pu …

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Comparison Of Structural Properties Of Some Liquid Crystals, Emi̇ne Mi̇ne Çapar Jan 2017

Comparison Of Structural Properties Of Some Liquid Crystals, Emi̇ne Mi̇ne Çapar

Turkish Journal of Physics

Molecular dynamics simulations were performed for three liquid crystalline molecules, 4-cyano-4$'$-octyloxybip- henyl (8OCB), n-p-cyanobenzylidene-p-octyloxyaniline (CBOOA), and p-n-hexyloxybenzylidene-p$'$-aminobenzonitrile (HBAB). Simulation data were obtained for three liquid crystals in the nematic and isotropic phases to analyze their structural properties. The imine spacer group in the Schiff bases induces a stepped core structure in which the linearity is maintained. The distributions of the angles between some defined vectors imply that the core segments of CBOOA and HBAB are more floppy than the 8OCB core. The biaxialities, molecular dimensions, and molecular anisotropies were calculated. The results were compared for three mesogens in the nematic …

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Promising Features Of In$_{0.5}$Ga$_{0.5}$N/Al$_{0.2}$Ga$_{0.8}$N Quantum Dot Lasers, Halima Bouchenafa, Badra Bouabdallah, Boucif Benichou Jan 2017

Promising Features Of In$_{0.5}$Ga$_{0.5}$N/Al$_{0.2}$Ga$_{0.8}$N Quantum Dot Lasers, Halima Bouchenafa, Badra Bouabdallah, Boucif Benichou

Turkish Journal of Physics

The group-III nitrides, InN, GaN, and AlN, and their alloys have emerged as one of the most important material classes for optoelectronic devices. The incorporation of quantum dots (QDs) as active material improves the performance of conventional optoelectronic devices, such as laser diodes. In this study, we present a theoretical analysis of the gain characteristics of In$_{x}$Ga$_{1-x}$N/Al$_{0.2}$Ga$_{0.8}$N three-dimensional quantum box lasers, based on the density matrix theory of semiconductor lasers with relaxation broadening. The study is done on three samples of QDs: GaN/Al$_{0.2}$Ga$_{0.8}$N, In$_{0.3}$Ga$_{0.7}$N/Al$_{0.2}$Ga$_{0.8}$N, and In$_{0.5}$Ga$_{0.5}$N/Al$_{0.2}$Ga$_{0.8}$N. A comparative study of the gain spectra of GaN/Al$_{0.2}$Ga$_{0.8}$N-based quantum-well and QD lasers is …

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Lightest And Heaviest Two-Neutron Halo Nuclei, $^{6}$He And $^{22}$C, Waleed Hwash Jan 2017

Lightest And Heaviest Two-Neutron Halo Nuclei, $^{6}$He And $^{22}$C, Waleed Hwash

Turkish Journal of Physics

The microscopic cluster model approach has been performed to study the nuclear structure of the lightest and heaviest two-neutron halo nuclei, $^{6}$He and $^{22}$C, respectively. The matter radius and binding energy for the $^{6}$He and $^{22}$C nuclei are calculated and the effect of the core deformation ($^{20}$C) on the properties of $^{22}$C nuclei is also discussed. Calculations have shown that the microscopic cluster model provides a good description of binding energy as well as matter radius in comparison to experimental data. The fittings of some parameters such as central potential depth (V$_{o})$, empirical constant (r$_{o})$, and surface diffuseness value (a) …

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Role Of Mg Doping In The Structural, Optical, And Electrical Characteristics Of Zno-Based Dsscs, İsmai̇l Polat, Sali̇h Yilmaz, Murat Tomaki̇n, Emi̇n Bacaksiz Jan 2017

Role Of Mg Doping In The Structural, Optical, And Electrical Characteristics Of Zno-Based Dsscs, İsmai̇l Polat, Sali̇h Yilmaz, Murat Tomaki̇n, Emi̇n Bacaksiz

Turkish Journal of Physics

ZnO- and Mg-doped ZnO samples are prepared by spray pyrolysis on conducting glass substrates to fabricate ZnO-based dye-sensitized solar cells (DSSCs). Influences of Mg-doping content on the power conversion efficiencies of ZnO-based DSSCs are investigated. X-ray diffraction results show that all the samples exhibit a hexagonal wurtzite structure. Scanning electron microscopy data indicate that the ZnO sample has uniform rods with 1 $\mu $m diameter. With respect to ZnO, the band gap value of 4 at.% Mg-doped ZnO samples improves to the value of 3.27 eV and a further increase in Mg level up to 6 at.% gives rise to …

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Design Of Turkish Accelerator And Radiation Laboratory In Ankara (Tarla) Facility Injector Magnets, Avni̇ Aksoy Jan 2017

Design Of Turkish Accelerator And Radiation Laboratory In Ankara (Tarla) Facility Injector Magnets, Avni̇ Aksoy

Turkish Journal of Physics

The installation of a high current thermionic gun-based injector capable to accelerate a maximum 1.5 mA electron beam at 250 keV and continuous wave (CW) for various bunch repetition rates has been continuing at the Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) since 2014. The injector, which is based on totally normal conducting technology, will mainly consist of a thermionic DC electron gun, two stage bunch compressor cavities operating at 260 MHz and 1.3 GHz, one dipole magnet, five solenoid lenses and an additional one dipole magnet that is going to be used as spectrometer, and several steerer magnets. …

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Bound States Of The Duffin-Kemmer-Petiau Equation For Square Potential Well With Position-Dependent Mass, Zoulikha Hammoud, Lyazid Chetouani Jan 2017

Bound States Of The Duffin-Kemmer-Petiau Equation For Square Potential Well With Position-Dependent Mass, Zoulikha Hammoud, Lyazid Chetouani

Turkish Journal of Physics

The effective mass Duffin-Kemmer-Petiau equation for spin 0 and spin 1 with a potential well is considered, and transcendental equations are derived for the energy eigenvalues. Numerical results are reported graphically, and the variations of the energy of the bound states are computed as a function of the well width and mass.

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Field-Free Molecular Alignment Control Of Filamentation, Necati̇ Kaya Jan 2017

Field-Free Molecular Alignment Control Of Filamentation, Necati̇ Kaya

Turkish Journal of Physics

With an approach of controlling the nonlinearity of medium rather than the light field, the effect of field-free molecular alignment on filamentation and resulting white-light generation is studied. This is done by measuring the rotational wavepacket evolution of nitrogen molecules after passing of a femtosecond laser pump pulse by observing the nonlinear propagation dynamics of a variably delayed filament-producing probe pulse.

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Phenomenological Potential Calculations For Cluster Decays, Asim Soylu Jan 2017

Phenomenological Potential Calculations For Cluster Decays, Asim Soylu

Turkish Journal of Physics

The half-lives of cluster decays from various nuclei having experimentally measured values have been calculated by using the Wentzel-Kramers-Brillouin method together with the Bohr-Sommerfeld quantization condition for three different types of phenomenological nuclear interactions: Woods-Saxon (WS), squared Woods-Saxon (WS-2), and mixed Woods-Saxon (mWS) potentials. By comparing the results with experimental values, rms values have been calculated. The half-lives of $^{14}$C, $^{15}$N, $^{16}$O, $^{17}$O, $^{18}$O, $^{20}$O, $^{22}$O, $^{23}$F, $^{22}$Ne, $^{24}$Ne, $^{25}$Ne, $^{26}$Ne, $^{28}$Mg, $^{30}$Mg, and $^{34}$Si decays from various isotopes whose experimental half-lives are unknown have also been calculated by using the WS, WS-2, and mWS potentials. The obtained results have …

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Bound-Free Pair Production With A Correction Term In Relativistic Heavy-Ion Collisions, Melek Yilmaz Şengül Jan 2017

Bound-Free Pair Production With A Correction Term In Relativistic Heavy-Ion Collisions, Melek Yilmaz Şengül

Turkish Journal of Physics

In our previous work, we calculated bound-free electron-positron pair production cross section without a correction term. In this work, bound-free electron-positron pair production with a correction term is considered to calculate the cross section for peripheral relativistic heavy ion collisions. The Dirac wave functions have been used for the leptons and first order corrections are included. It is seen that the results for the production cross sections are considerably smaller than those of the previous calculations. We applied the same method for the calculations of the antihydrogen production cross sections as well.

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A Dft Study On The Electronic Structure Of Tungsten Trioxide Polymorphs, Masoud Mansouri, Tahereh Mahmoodi Jan 2017

A Dft Study On The Electronic Structure Of Tungsten Trioxide Polymorphs, Masoud Mansouri, Tahereh Mahmoodi

Turkish Journal of Physics

Tungsten trioxide ($WO_{3})$ is an intermediate product in the recovery of tungsten from its minerals. Recently, it has attracted increasing attention due to its exclusive structural properties and its high potential in electronic applications. The crystal lattice of tungsten trioxide is highly dependent on temperature. In this paper we investigated the equilibrium structure of tungsten trioxide in four crystal systems, i.e. monoclinic system, tetragonal system, orthorhombic system, and cubic system. We did our first principle calculations using a pseudopotential model based on the spin dependent density functional theory and implementing generalized gradient approximation for exchange correlation energy. In each case, …

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Identification Of The Hadronic Interaction Layer In A Highly Granular Calorimeter By Multivariate Techniques, Burak Bi̇lki̇ Jan 2017

Identification Of The Hadronic Interaction Layer In A Highly Granular Calorimeter By Multivariate Techniques, Burak Bi̇lki̇

Turkish Journal of Physics

Calorimetry in future and upgrade collider detectors has a clear overall trend towards high granularity, both laterally and longitudinally. This trend is a requirement for the full exploitation of particle flow algorithms, which reconstruct individual particles using the subdetector that provides the best resolution for this specific particle. The increased level of detail in the event topologies due to higher segmentation of the calorimeter provides additional handles for several calorimetric measurements, such as the identification of the hadronic interaction layer, which is not possible for calorimeters with traditional tower geometry. Here, the power of using multivariate statistical techniques in the …

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Design Studies For The Beam Position Monitor (Bpm) Front-End Electronics Of The Turkish Accelerator And Radiation Laboratory In Ankara (Tarla), Ayhan Aydin, Ergün Kasap Jan 2017

Design Studies For The Beam Position Monitor (Bpm) Front-End Electronics Of The Turkish Accelerator And Radiation Laboratory In Ankara (Tarla), Ayhan Aydin, Ergün Kasap

Turkish Journal of Physics

A beam diagnostics system is vitally important to operate all accelerator-based facilities. The system provides information about beam characteristics and enables requested beam parameters to be achieved. The main parameters, such as beam energy, current, emittance, and beam position, must be diagnosed and controlled during the operation of an accelerator. Beam position monitors (BPMs) are an essential tool for diagnosing a system of accelerators. They are used to define the position of the beam traversing through the beam pipe at relativistic speed. These tools can be used to achieve the required beam quality as well as protecting the entire system …

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On The Contribution Of The 6.7 Kev Line Emission Of The Algol Binary System To The 6.7 Kev Line Emission From The Galactic Ridge, Ambrose Chukwudi Eze, Romanus Nwachukwu Chijioke Eze, Sudum Esaenwi Jan 2017

On The Contribution Of The 6.7 Kev Line Emission Of The Algol Binary System To The 6.7 Kev Line Emission From The Galactic Ridge, Ambrose Chukwudi Eze, Romanus Nwachukwu Chijioke Eze, Sudum Esaenwi

Turkish Journal of Physics

We carried out spectroscopic analysis of the extracted stellar flare of the Algol binary system observed using the Suzaku satellite (OBSID: 401093010), and resolved a strong 6.7 keV line emission. The 6.7 keV line emission of the Algol binary system is similar to the 6.7 keV line of the galactic ridge X-ray emission (GRXE). The equivalent width (EW) compared favorably with the EW of the 6.7 keV emission line obtained from different galactic ridge regions. In the galaxy, we have a reasonable number of Algol binary systems and many other stars as strong coronal X-ray emitters characterized by frequent quiescent …

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The Milne Problem Using The P$_{N}$ Method For A Nonabsorbing Medium With Linearly Anisotropic Scattering, Mustafa Çeti̇n Güleçyüz, Ahmet Ersoy Jan 2017

The Milne Problem Using The P$_{N}$ Method For A Nonabsorbing Medium With Linearly Anisotropic Scattering, Mustafa Çeti̇n Güleçyüz, Ahmet Ersoy

Turkish Journal of Physics

The Milne problem, known as one of the classical problems of radiative transfer and neutron transport theory, is solved using the P$_{N}$ method for a nonabsorbing medium (c = 1) with a linearly anisotropic scattering kernel. Specular and diffuse reflection boundary conditions are taken into account. The numerical results are listed for different selected parameters. Some results are also compared with the literature.

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A Theoretical Study Of Radio Wave Attenuation Through A Polycrystalline Silicon Solar Cell, Adama Ouedraogo, Vinci De Dieu Bokoyo Barandja, Issa Zerbo, Martial Zoungrana, Emmanuel Wendsongre Ramde, Dieudonne Joseph Bathiebo Jan 2017

A Theoretical Study Of Radio Wave Attenuation Through A Polycrystalline Silicon Solar Cell, Adama Ouedraogo, Vinci De Dieu Bokoyo Barandja, Issa Zerbo, Martial Zoungrana, Emmanuel Wendsongre Ramde, Dieudonne Joseph Bathiebo

Turkish Journal of Physics

One-dimensional study of both electronic and electrical parameters of a silicon solar cell in the presence or not of an electric field, a magnetic field, or an electromagnetic field does not take into account the grain size and the grain boundary recombination velocity. A three-dimensional study, on the contrary, takes those factors into account. However, the three-dimensional study poses the problem of the attenuation of the wave in the grain of the polycrystalline solar cell as well as the issue of finding the expressions of its components. This study aimed to solve these issues by considering radio waves, which are …

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Remarks On The Treatments Of Nonsolvable Potentials, Bülent Gönül, Yücel Cançeli̇k Jan 2017

Remarks On The Treatments Of Nonsolvable Potentials, Bülent Gönül, Yücel Cançeli̇k

Turkish Journal of Physics

A recently introduced scheme is extended to propose an algebraic nonperturbative approach for the analytical treatment of Schrödinger equations with nonsolvable potentials involving an exactly solvable potential form together with an additional potential term. As an illustration the procedure is successfully applied to the Cornell potential by means of very simple algebraic manipulations. However, instead of providing numerical eigenvalues for the only consideration of the small strength of the related linear potential as in the previous reports, the present model puts forward a clean route to interpret related experimental or precise numerical results involving a wide range of the linear …

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Enhanced Electro-Optic Modulation Of Linbo$_{3}$-Based Photonic Crystal Cavities With Dual Mode And Polarization Operation, Fulya Bağci, Gökhan Kurt, Bariş Akaoğlu, Ekmel Özbay Jan 2017

Enhanced Electro-Optic Modulation Of Linbo$_{3}$-Based Photonic Crystal Cavities With Dual Mode And Polarization Operation, Fulya Bağci, Gökhan Kurt, Bariş Akaoğlu, Ekmel Özbay

Turkish Journal of Physics

A high output transmission and high quality factor, compact LiNbO$_{3}$-based Fabry-Perot-type photonic crystal cavity is reported that can be used in electro-optical modulators at optical communication wavelengths. The electro-optic effect is 123 times enhanced as compared to the bulk material as a result of the slow light effect. The transmission wavelength is found to depend linearly on the applied voltage with 1.2 nm/V modulation sensitivity. Moreover, an externally switchable dual mode regime with high quality factors and transmissions is realized. High transmissions and high quality factors are also obtained for both transverse-electric and transverse-magnetic polarizations simultaneously.

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Achieving Carrier And Photon Confinement In Ga(Nasp)/Algap/Gap Qws On Si Substrates, Ömer Lütfi̇ Ünsal, Beşi̇re Gönül Jan 2017

Achieving Carrier And Photon Confinement In Ga(Nasp)/Algap/Gap Qws On Si Substrates, Ömer Lütfi̇ Ünsal, Beşi̇re Gönül

Turkish Journal of Physics

A detailed comparative theoretical analysis on both carrier and photon confinement of dilute nitride direct bandgap GaN$_{x}$As$_{1-x-y}$P$_{y}$ with that of GaAs$_{1-y}$P$_{y}$ on Si substrates is presented. Model calculations indicate that optical confinement factor of GaAs$_{1-y}$P$_{y}$/GaP is greater than that of GaN$_{x}$As$_{1-x-y}$P$_{y}$/GaP for all concentrations. We have demonstrated that one can improve the optical confinement factor of GaN$_{x}$As$_{1-x-y}$P$_{y}$/GaP by using an Al$_{z}$Ga$_{1-z}$P cladding layer.

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Possible Variations In Sunspot Groups Before Flaring Activity During Solar Cycles 23 And 24, Ali̇ Kilçik, Seray Şahi̇n Jan 2017

Possible Variations In Sunspot Groups Before Flaring Activity During Solar Cycles 23 And 24, Ali̇ Kilçik, Seray Şahi̇n

Turkish Journal of Physics

We investigated the possible morphological variations observed in sunspot groups on the day before flaring activity occurred between January 1996 and November 2014. We found that 77% of all flaring sunspot groups were large and complex (D, E, and F modified Zurich classes). In addition, the Zurich classification of A, B, and C class sunspot groups changed more than 50%, while the remaining groups (D, E, F, and H) did not change considerably before the flare activity. Results showed that there was a remarkable increase in the sunspot areas of groups D, E, and F; in contrast, the sunspot areas …

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Lime: Semiautomated Line Measurement And Identification From Stellar Spectra, Ti̇mur Şahi̇n Jan 2017

Lime: Semiautomated Line Measurement And Identification From Stellar Spectra, Ti̇mur Şahi̇n

Turkish Journal of Physics

We present LIME (Line Measurements from ECHELLE Spectra), an IDL-based code, as a powerful tool for semiautomated stellar line measurement and identification. Interactively selected line positions (i.e. wavelengths) are compared with a master line list of the user's selections. Each unknown line that the user interactively chooses is displayed with potential identifications provided by the code in the vicinity of the selected line. The best identification is evaluated on the basis of several criteria (e.g., atomic/molecular line information, wavelength displacement, and theoretical equivalent width for solar atmospheric values). We examined the identifications by LIME in the spectra of post-red supergiant …

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Influence Of Silicon Dioxide Medium On The Structural And Electrical Properties Of Nickel Zinc Ferrite, Jacob George, Abraham Kutticheril Eapen Jan 2017

Influence Of Silicon Dioxide Medium On The Structural And Electrical Properties Of Nickel Zinc Ferrite, Jacob George, Abraham Kutticheril Eapen

Turkish Journal of Physics

Nickel zinc ferrite [(Ni$_{0.65}$Zn$_{0.35}$Fe$_{2}$O$_{4}) _{x}$ / (SiO$_{2}) _{1-x}$ where, x = 1.0, 0.85, 0.65, 0.50, 0.35, and 0.15] is synthesized using the glyoxylate precursor method. The synthesis, characterization, and electrical study of nickel zinc ferrites/SiO$_{2}$ powder with low dielectric constant, very low conductivity, and loss tangent with low frequency dispersion, suitable for good insulators, is reported here. X-ray diffraction, TGA, and FT-IR studies are employed for identifying crystalline phases and structure. Crystallite size is calculated by the Scherrer formula and Williamson--Hall equation and found to fall in the range of 4.9--25 nm. TEM of the samples shows spherical particles of …

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Effect Of Uv And Gamma Rays On Bulk Etching Of The Pokalon Track Detector, Madhusoodanan Pdmajam Gangadathan, Venkidasubramanian Sankar, Nishanth Pothiyodathu, Krishna Muraleedhara Varier Jan 2017

Effect Of Uv And Gamma Rays On Bulk Etching Of The Pokalon Track Detector, Madhusoodanan Pdmajam Gangadathan, Venkidasubramanian Sankar, Nishanth Pothiyodathu, Krishna Muraleedhara Varier

Turkish Journal of Physics

Solid-state nuclear track detectors (SSNTDs) find applications in many fields of science and technology. Polycarbonates like CR-39 or Lexan are most widely used for such applications. Pokalon is a relatively new member of the polycarbonate family of SSNTDs. It has the same monomer as that of Makrofol. In the present work we have studied the bulk etching characteristics of Pokalon at different temperatures and normalities of NaOH etchant with and without magnetic stirring. The effect of UV and gamma irradiation on the bulk etch rate has also been studied. From the bulk etch rate values at different temperatures, we have …

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Investigation Of A Novel Temperature-Sensing Mechanism Based On Strain-Induced Optical Path-Length Difference In A Multicore Optical Fiber, Belkis Gökbulut, Sema Güvenç, Mehmet Naci̇ İnci̇ Jan 2017

Investigation Of A Novel Temperature-Sensing Mechanism Based On Strain-Induced Optical Path-Length Difference In A Multicore Optical Fiber, Belkis Gökbulut, Sema Güvenç, Mehmet Naci̇ İnci̇

Turkish Journal of Physics

A four-core optical fiber is employed to investigate a novel temperature-sensing mechanism, which is based on the strain-induced optical path-length difference between the fiber core pairs. A short segment of a four-core fiber is wound around a solid stainless steel cylinder to form a tight circular loop, which is exposed to temperatures of up to 100 $^{\circ}$C. Temperature-induced radial expansion of the stainless steel cylinder causes a shear strain in the fiber and introduces an optical path-length difference between the fiber core pairs. This results in a total phase shift of about 20.40 $\pm $ 0.29 rad in the interference …

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Proton--Proton And Proton--Antiproton Differential Elastic Cross Sections Modeling At High And Ultra-High Energies Using A Hybrid Computing Paradigm, Elsayed Eldahshan Jan 2017

Proton--Proton And Proton--Antiproton Differential Elastic Cross Sections Modeling At High And Ultra-High Energies Using A Hybrid Computing Paradigm, Elsayed Eldahshan

Turkish Journal of Physics

This work presents a hybrid computing technique for modeling the differential elastic cross section of both proton--proton ``pp'' and proton--antiproton ``pp(bar)'' collisions from high to ultra-high energy regions (from 13.9 GeV to 14 TeV) as a function of the center-of-mass energy ``s'' squared and four momentum transfer squared ``t''. We proposed a genetic algorithm (GA) and support vector regression (SVR) hybrid techniques to calculate and predict the ``differential elastic cross section'' of both ``pp'' and ``pp(bar)''. Our proposed GA-SVR hybrid model shows a good match to the available experimental data, as well as predicting the latest and future ``TOTEM'' experiments …

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Marder Type Universe With Bulk Viscous String Cosmological Model In $F(R,T)$ Gravity, Sezgi̇n Aygün Jan 2017

Marder Type Universe With Bulk Viscous String Cosmological Model In $F(R,T)$ Gravity, Sezgi̇n Aygün

Turkish Journal of Physics

In this study, we have investigated homogeneous and anisotropic Marder space-time with bulk viscous string matter distribution in $f(R,T)$ gravity. For this aim we have used the anisotropy feature $(\frac{\sigma_{x}^{x} }{\theta })$ of Marder space-time and a deceleration parameter in two different $f(R,T)$ models. We have obtained bulk viscous matter distribution solutions in $f(R,T)$ gravity. Finally, some kinematical and physical properties are discussed.

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