Bulletin of the American Physical Society
Joint Fall 2017 Meeting of the Texas Section of the APS, Texas Section of the AAPT, and Zone 13 of the Society of Physics Students
Volume 62, Number 16
Friday–Saturday, October 20–21, 2017; The University of Texas at Dallas, Richardson, Texas
Session B5: Materials Science I |
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Chair: Kuei Sun, University of Texas at Dallas Room: DGAC 1.131 |
Friday, October 20, 2017 2:45PM - 2:57PM |
B5.00001: Composite reinforced metallic cylinder for high speed rotation Dr. Sahadev Pradhan The objective of the present study is to design and development of the composite reinforced thin metallic cylinder to increase the peripheral speed significantly and thereby improve the separation performance in a centrifugal gas separation processes through proper optimization of the internal parameters. According to Dirac equation (Cohen (1951)), the maximum separative work for a centrifugal gas separation process increase with 4th power of the peripheral speed. Therefore, it has been intended to reinforce the metallic cylinder with composites (carbon fibers: T-700 and T- 1000 grade with suitable epoxy resin) to increase the stiffness and hoop stress so that the peripheral speed can be increased significantly, and thereby enhance the separative output. Here, we have developed the mathematical model to investigate the elastic stresses of a laminated cylinder subjected to mechanical, thermal and thermo-mechanical loading. A detailed analysis is carried out to underline the basic hypothesis of each formulation. Further, we evaluate the steady state creep response of the rotating cylinder and analyze the stresses and strain rates in the cylinder. [Preview Abstract] |
Friday, October 20, 2017 2:57PM - 3:09PM |
B5.00002: Calculation of distributio of Temperature and potential on RRAM using finite element method Binod D.C., Wilhelmus Geerts, Aron Median Finite element calculations are being performed on resistive RAM (RRAM) devices to determine the electric potential and temperature distribution across the wafer. RRAM is a non-volatile memory technology that is currently being considered to replace Flash memory beyond 14 nm technology node. The calculations are performed using Comsol Multiphysics using the electric current and heat transfer in solids features. We used three Multiphysics nodes, i.e. Electromagnetic heat source, the boundary heat source and temperature coupling. The device was built from a plane geometry of substrate (fused quartz), bottom electrode (Pt), oxide (NiO), and top electrode (Pt) and then extruded each in the z-direction. A physics controlled normal mess was used for the calculations consisting of tetrahedral elements. Calculations were performed for a high and low resistive memory layer. In both cases the potential varies linearly along the electrodes. For the high resistive device, the temperature is highest in the center. For the low resistive device Joule heating mainly takes place along the electrodes and the temperature varies much less across the wafer. This work was supported by a DOD grant (HBCU/MI grant W911NF-15-1- 0394). [Preview Abstract] |
Friday, October 20, 2017 3:09PM - 3:21PM |
B5.00003: Synthesis and high thermal conductivity in cubic BAs and BP crystals Sheng Li, Qiye Zheng, Xiaoyuan Liu, Ryan Little, Evan Glaser, David Broido, David Cahill, Bing Lv The zinc blende cubic BAs and BP, due to their potential ultra-high thermal conductivity ($\kappa )$ calculated through first principle approach, have attracted significant research efforts in the past few years. In order to experimentally verify the predicted high $\kappa $ values, high quality defect-free single crystal growth is needed to eliminate phonon scattering caused by defects such as deficiency, anti-site defects, voids, impurities, twin/grain boundaries. Herein, we have carried out systematical studies to: 1) find out the suitable crystal growth techniques for BAs and BP despite many challenges ; 2) investigate the growth mechanism to optimatize the crystal growth; and 3) grow large size of BAs and BP crystals up to 1.5 mm size where a high $\kappa $ up to 600 W/m/K is obtained from time-domain thermoreflectance (TDTR) measurments. The obtained $\kappa $ value is much higher than that of AlN (\textasciitilde 400 W/m/K), and is only smaller than that of C-based diamond and nanotube/graphene. [Preview Abstract] |
Friday, October 20, 2017 3:21PM - 3:33PM |
B5.00004: Impact of physics-based parameters on diverse design architecture of perovskite solar cells Aditya Kumar Mishra, Deidra Hodges, Jason D. Slinker Solution processed organic--inorganic metal halide perovskite and its derivatives have emerged as one of the leading thin film photovoltaic technology due to their remarkable increase in power conversion efficiency in a very short period of time. In the context of increasing the efficiency and sustainability of perovskite solar cells (PSC) devices, we comprehensively analyzed the impact of doped and un-doped perovskite thin film in diverse design architectures of PSCs. Our method emphasized the~role of different charge carrier layers and its effect on interfacial recombination mechanism and charge extraction rate within PSC devices.~We also considered morphological control, crystallographic functionality, chemistry and charge transport properties of perovskite thin film for different architecture of PSC devices. We observed that photocurrent is~substantially influenced by interfacial recombination process and photovoltage has functional relationship with defect density of perovskite absorption layer. A new contour mapping method to understand the characteristics of current density--voltage ($J$--$V)$ curves for each device as a function of perovskite layer thickness provided an important insight about the distribution spectrum of photovoltaic properties. The Functional relationship of solar cell efficiency and fill factor with perovskite layer thickness are also discussed. [Preview Abstract] |
Friday, October 20, 2017 3:33PM - 3:45PM |
B5.00005: Electronic and optical properties of the CuAlO$_{2}$ and AgAlO$_{2}$ transparent conductor oxides: a first principles study James Shook, Luisa Scolfaro Transparent semiconductors are an exciting area of research due to their applicability in photovoltaic cells and flat panel displays. Many well-known n-type transparent conducting oxides (TCOs) have been documented, but the search for commercially viable p-type TCOs continues due to characteristically large hole effective masses and low hole mobility arising from the localized valence p-states of O. The delafossites, CuAlO$_{2}$ and AgAlO$_{2}$ (XAO), show promise as viable p-type TCOs because of the delocalization of valence states that results from hybridization of Cu/Ag d-states with O p-states. This work presents the electronic and optical properties of 2H-XAO using density functional theory as implemented in the VASP code. The exchange-correlation energy of the 8 atom 2H-XAO hexagonal primitive cell is treated using the generalized gradient approximation and the modified Becke-Johnson approximation with the use of a Hubbard energy correction for the Cu/Ag d-orbitals, in order to obtain values for the band gaps similar to experimental values. Optical properties are derived from the complex dielectric function, which is calculated using the charge density obtained from the self-consistent calculation. The presented work is scrutinized against available experimental results. [Preview Abstract] |
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