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Öğe DFT study for the mechanical and electronic properties of Mg3BHx (x=l,4,7) compounds for hydrogen storage applications(American Institute of Physics Inc., 2019) Gencer, Ayşenur; Sürücü, G.The electronic devices such as cell phones, laptops etc. are a necessary part of our daily life that requires portable power sources. Hydrogen being the most abundant element on the Earth, is an excellent energy carrier with high energy capacity that enable to use hydrogen storage methods in portable power sources. In addition, hydrogen storage could be essential to store the energy obtained from the renewable energy sources. The solid state hydrogen storage is an encouraging method for hydrogen storage applications. In this study, Mg3BHx (x=1,4,7) compounds have been studied using Density Functional Theory (DFT) with the Vienna Ab-initio Simulation Package (VASP). The elastic constants have been obtained for the optimized structures. In addition, the band structures have been determined with the corresponding density of states. The gravimetric storage capacities have been determined for these compounds. Mg3BHx compounds with mechanical stability could be promising compounds for hydrogen storage applications. © 2019 Author(s).Öğe Effect of hydrogen doping to mgtih3 perovskite type hydride to enhance hydrogen storage properties(Institute of Electrical and Electronics Engineers Inc., 2019) Gencer, Ayşenur; Sürücü, G.MgTiH3 perovskite type hydride has been investigated for the hydrogen doping effect using the first principles calculation with the Vienna Ab-initio Simulation Package. The hydrogen doping positions have been determined and the hydrogen atoms doped to the optimized MgTiH3 compound. The structural optimizations show that the hydrogen doping results with MgTiH3x (x=3, 6, 8) compounds that are thermodynamically stable. The electronic properties have been studied for MgTiH3 and hydrogen doped MgTiH3x (x=3, 6, 8) compounds. The calculated band structures show that these compounds have metallic character. In addition, the hydrogen storage properties of MgTiH3 and MgTiH3x (x=3, 6, 8) compounds have been investigated and the hydrogen doping to MgTiH3 enhances the hydrogen storage capacity and the hydrogen desorption temperature. This study is the first investigation for hydrogen doping to MgTiH3 perovskite type hydride as known up to date and could be a leading study for the future considerations. © 2019 IEEE.Öğe Evaluation of mechanical properties of Bi12SiO20 sillenite using first principles and nanoindentation(Taylor & Francis Ltd, 2021) Işık, Mehmet; Sürücü, G.; Gencer, Ayşenur; Gasanly, N. M.The mechanical and anisotropic elastic properties of Bi12SiO20 (BSO) were investigated using density functional theory (DFT) calculations and nanoindentation. The calculated and experimentally observed XRD patterns of the compound were reported and the crystal structure of the BSO was determined to be cubic with the lattice constant of a = 1.025 nm. The second-order elastic constants and related polycrystalline elastic moduli (e.g. shear modulus, Young’s modulus, Poisson’s ratio, linear compressibility and hardness) were calculated. The calculated elastic constants indicated that BSO is mechanically stable and exhibits anisotropic characteristics. Moreover, the directional dependencies of sound wave velocities were investigated in three dimensions. Pressure-dependent bulk modulus was plotted at temperatures between 0 and 800 K. Hardness and Young’s modulus were also determined by performing nanoindentation experiments on (222) and (631) planes of the BSO single crystal. The analyses of the experimental nanoindentation data resulted in hardness and Young’s modulus values of 7.2 and 97.0 GPa, respectively. The results of DFT and nanoindentation were discussed throughout the paper. The results of the present paper would provide valuable information on the mechanical behaviours of the BSO for the optoelectronic device applications.Öğe First principles study of the vibrational and thermo-elastic properties of BaScO3 perovskite oxide(American Institute of Physics Inc., 2019) Gencer, Ayşenur; Sürücü, G.The vibrational and thermo-elastic properties of BaScO3 compound have been investigated using Density Functional Theory (DFT) with Vienna Ab initio Simulation Package (VASP). Perovskite materials could crystallize in five possible crystal structures: orthorhombic, tetragonal, rhombohedral, hexagonal, and cubic. Therefore, BaScO3 has been investigated for these five possible crystal structures and the most stable phase has been determined as the orthorhombic phase. Then, the vibrational properties have been calculated and dynamical stability of the most stable phase of BaScO3 has been determined. In addition, thermo-elastic properties have been studied in the temperature range between 0 to 1000 K and pressure range between 0 to 20 GPa. As we know up to date, this is the first investigation of the vibrational and thermo-elastic properties of BaScO3 compound that could direct the future studies. © 2019 Author(s).
