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Article Citation - WoS: 4Citation - Scopus: 5Thermoluminescence Properties of Tl2ga2< Layered Single Crystals(Amer inst Physics, 2013) Delice, S.; Isik, M.; Bulur, E.; Gasanly, N. M.The trap center(s) in Tl2Ga2S3Se single crystals has been investigated from thermoluminescence (TL) measurements in the temperature range of 10-300 K. Curve fitting, initial rise, and peak shape methods were applied to observed TL glow curve to evaluate the activation energy, capture cross section, and attempt-to-escape frequency of the trap center. One trapping center has been revealed with activation energy of 16 meV. Moreover, the characteristics of trap distribution have been studied using an experimental technique based on different illumination temperature. An increase of activation energy from 16 to 58 meV was revealed for the applied illumination temperature range of 10-25K. (C) 2013 AIP Publishing LLC.Conference Object Citation - WoS: 6Discrete calculus of variations(Amer inst Physics, 2004) Guseinov, GSThe continuous calculus of variations is concerned mainly with the determination of minima or maxima of certain definite integrals involving unknown functions. In this paper, a discrete calculus of variations for sums is treated, including the discrete Euler-Lagrange equation.Article Citation - WoS: 24Citation - Scopus: 24Symplectic and multisymplectic Lobatto methods for the "good" Boussinesq equation(Amer inst Physics, 2008) Aydin, A.; Karasoezen, B.In this paper, we construct second order symplectic and multisymplectic integrators for the "good" Boussineq equation using the two-stage Lobatto IIIA-IIIB partitioned Runge-Kutta method, which yield an explicit scheme and is equivalent to the classical central difference approximation to the second order spatial derivative. Numerical dispersion properties and the stability of both integrators are investigated. Numerical results for different solitary wave solutions confirm the excellent long time behavior of symplectic and multisymplectic integrators by preservink local and global energy and momentum. (C) 2008 American Institute of Physics.Conference Object Citation - WoS: 1Operator Splitting of the Kdv-Burgers Type Equation With Fast and Slow Dynamics(Amer inst Physics, 2010) Aydin, A.; Karasozen, B.The Korteweg de Vries-Burgers (KdV-Burgers) type equation arising from the discretization of the viscous Burgers equation with fast dispersion and slow diffusion is solved using operator splitting. The dispersive and diffusive parts are discretized in space by second order conservative finite differences. The resulting system of ordinary differential equations are composed using the time reversible Strang splitting. The numerical results reveal that the periodicity of the solutions and the invariants of the KdV-Burgers equation are well preserved.Article Citation - WoS: 3Citation - Scopus: 4Hall Mobility and Photoconductivity in Tlgases Crystals(Amer inst Physics, 2013) Qasrawi, A. F.; Gasanly, N. M.In this work, the fundamental properties of the TlGaSeS single crystals are investigated by means of temperature dependent electrical resistivity and Hall mobility. The crystal photo-responsibility as function of illumination intensity and temperature is also tested in the temperature range of 350-160 K. The study allowed the determination of acceptor centers as 230 and 450 meV below and above 260 K, and recombination centers as 181, 363, and 10 meV at low, moderate, and high temperatures, respectively. While the temperature-dependent Hall mobility behaved abnormally, the photoconductivity analysis reflected an illumination intensity dependent recombination center. Namely, the recombination center increased from 10 to 90 meV as the light intensity increased from 27.9 to 76.7 mW cm(-2), respectively. That strange behavior was attributed to the temporary shift in Fermi level caused by photoexcitation. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4775577]Article Citation - WoS: 17Citation - Scopus: 16Multisymplectic Box Schemes for the Complex Modified Korteweg-De Vries Equation(Amer inst Physics, 2010) Aydin, A.; Karasozen, B.In this paper, two multisymplectic integrators, an eight-point Preissman box scheme and a narrow box scheme, are considered for numerical integration of the complex modified Korteweg-de Vries equation. Energy and momentum preservation of both schemes and their dispersive properties are investigated. The performance of both methods is demonstrated through numerical tests on several solitary wave solutions. (C) 2010 American Institute of Physics. [doi:10.1063/1.3456068]Article Citation - WoS: 19Citation - Scopus: 19Temperature-Dependent Band Gap Characteristics of Bi12sio20< Single Crystals(Amer inst Physics, 2019) Isik, M.; Delice, S.; Gasanly, N. M.; Darvishov, N. H.; Bagiev, V. E.Bi12SiO20 single crystals have attracted interest due to their remarkable photorefractive characteristics. Since bandgap and refractive index are related theoretically to each other, it takes much attention to investigate temperature dependency of bandgap energy to understand the behavior of photorefractive crystals. The present study aims at investigating structural and optical characteristics of photorefractive Bi12SiO20 single crystals grown by the Czochralski method. The structural characterization methods indicated that atomic composition ratios of constituent elements were well-matched with the chemical compound Bi12SiO20, and grown crystals have a cubic crystalline structure. Optical properties of crystals were investigated by room temperature Raman spectroscopy and temperature-dependent transmission measurements between 10 and 300 K. The analyses of transmittance spectra by absorption coefficient and derivative spectrophotometry techniques resulted in energy bandgaps decreasing from 2.61 to 2.48 eV and 2.64 to 2.53 eV as temperature was increased from 10 to 300 K. The Varshni model was applied to analyze temperature-bandgap energy dependency.Conference Object Renewability and Sustainability Aspects of Nuclear Energy(Amer inst Physics, 2014) Sahin, SumerRenewability and sustainability aspects of nuclear energy have been presented on the basis of two different technologies: (1) Conventional nuclear technology; CANDU reactors. (2) Emerging nuclear technology; fusion/fission (hybrid) reactors. Reactor grade (RG) plutonium, U-233 fuels and heavy water moderator have given a good combination with respect to neutron economy so that mixed fuel made of (ThO2/RG-PuO2) or (ThC/RG-PuC) has lead to very high burn up grades. Five different mixed fuel have been selected for CANDU reactors composed of 4 % RG-PuO2 + 96 % ThO2; 6 % RG-PuO2 + 94 % ThO2; 10 % RG-PuO2 + 90 % ThO2; 20 % RG-PuO2 + 80 % ThO2; 30 % RG-PuO2 + 70 % ThO2, uniformly taken in each fuel rod in a fuel channel. Corresponding operation lifetimes have been found as similar to 0.65, 1.1, 1.9, 3.5, and 4.8 years and with burn ups of similar to 30 000, 60 000, 100 000, 200 000 and 290 000 MW.d/ton, respectively. Increase of RG-PuO2 fraction in radial direction for the purpose of power flattening in the CANDU fuel bundle has driven the burn up grade to 580 000 MW. d/ton level. A laser fusion driver power of 500 MWth has been investigated to burn the minor actinides (MA) out of the nuclear waste of LWRs. MA have been homogenously dispersed as carbide fuel in form of TRISO particles with volume fractions of 0, 2, 3, 4 and 5 % in the Flibe coolant zone in the blanket surrounding the fusion chamber. Tritium breeding for a continuous operation of the fusion reactor is calculated as TBR = 1.134, 1.286, 1.387, 1.52 and 1.67, respectively. Fission reactions in the MA fuel under high energetic fusion neutrons have lead to the multiplication of the fusion energy by a factor of M = 3.3, 4.6, 6.15 and 8.1 with 2, 3, 4 and 5 % TRISO volume fraction at start up, respectively. Alternatively with thorium, the same fusion driver would produce similar to 160 kg U-233 per year in addition to fission energy production in situ, multiplying the fusion energy by a factor of similar to 1.3.Conference Object The Prospect of Nuclear Energy in Turkiye Especially After Fukushima Accident(Amer inst Physics, 2014) Sahin, SumerTurkiye considers since mid-50's to use nuclear electricity, but Government and bureaucracy have continuously postponed reactor construction. However, since 2010 the case has gained a real shape. Official agreement has been signed for the construction of 4 units of Russian VVER type reactors with installed power of 4x1200 MWel. It is expected that they will begin to deliver electricity early 20's. Further negotiations are being conducted with Japanese Mitsubashi and French AREVA. The target is to have nuclear electricity by 2023 at the 100th anniversary of Turkish Republic.Conference Object Citation - WoS: 1Multisymplectic Schemes for the Complex Modified Korteweg-De Vries Equation(Amer inst Physics, 2008) Aydin, A.; Karasoezen, B.In this paper, the multisymplectic formulation of the CMKdV(complex modified Korteweg-de Vries equation) is derived. Based on the multisymplectic formulation, the eight-point multisymplectic Preissman scheme and a linear-nonlinear multisymplectic splitting scheme are developed. Both methods are compared numerically with respect to the conservation of local and global quantities of the CMKdV equation.
