Bulletin of the American Physical Society
Joint Fall 2012 Meeting of the Texas Sections of the APS, AAPT, and Zone 13 of the SPS
Volume 57, Number 10
Thursday–Saturday, October 25–27, 2012; Lubbock, Texas
Session B1: Invited & Contributed Papers: Industrial & Applied Physics |
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Chair: Roger L. Lichti, Texas Tech University Room: Holiday Inn Towers University A |
Friday, October 26, 2012 10:30AM - 11:05AM |
B1.00001: The Important Role of Physics in Industry and Economic Development Invited Speaker: Igor Alvarado Good Physics requires good education. Good education translates into good Physics professionals. The process starts early with Science, Technology, Engineering and Mathematics (STEM) education programs for Middle and High-School students. Then it continues with competitive higher education programs (2 years and 4 years) at colleges and universities designed to satisfy the needs of industry and academia. The research work conducted by graduate students in Physics (and Engineering Physics) frequently translates into new discoveries and innovations that have direct impact in society (e.g. Proton Cancer Therapy). Some of the major and largest scientific experiments in the world today are physics-centered (e.g. Large Hadron Collider-LHC) that generate employment and business opportunities for thousands of scientists, academic research groups and companies from around the world. New superconducting magnets and advanced materials that have resulted from previous research in physics are commonly used in these extreme experiments. But not all physicists will end up working at these large high-energy physics experiments, universities or National Laboratories (e.g. Fermilab); industry requires new generations of (industrial) physicists in such sectors as semiconductor, energy, space, life sciences, defense and advanced manufacturing. This work presents an industry perspective about the role of Physics in economic development and the need for a collaborative Academic-Industry approach for a more effective translational research. A series of examples will be presented with emphasis in the measurement, control, diagnostics and computing capabilities needed to translate the science (physics) into innovations and practical solutions that can benefit society as a whole. [Preview Abstract] |
Friday, October 26, 2012 11:05AM - 11:17AM |
B1.00002: NMR/MRI blood flow magnetization equation in the rotating frame of reference- Part I Dilip De This paper describes thoroughly the need and the method of deriving the first of its kind the NMR/MRI blood flow magnetization (y component) equation in the rotating frame when rf B$_{1}$ field is applied along laboratory X direction. The equation is expected to serve as the mother equation for accurate non invasive blood flow quantification through all NMR/MRI experiments. It is shown how Awojyogbe's equation of blood flow magnetization can be obtained from above equation under assumption of constant $B_{1}$ field and $v_{y}$ = 0. The method of deriving the equation can be applied to modify Bloch Torey Diffusion MRI equation to include relaxation times and flow and also to derive the NMR/MRI spin flow magnetization equation in the laboratory frame of reference. The derivation of the corresponding flow equation for longitudinal component of magnetization will be discussed in a separate paper. [Preview Abstract] |
Friday, October 26, 2012 11:17AM - 11:29AM |
B1.00003: Plasma Relaxation Parameters From High Power Microwave Excitation Sterling Beeson, George Laity, Andreas Neuber The recombination/relaxation physics of plasma generated from a 3 MW, 3$\mu$s pulse-width, high power microwave (HPM) pulse is investigated. This pulse is incident on a microwave transparent dielectric window which separates the source (vacuum) environment from the atmospheric test chamber (pressure and gas type are user controlled). During the pulse, the value of E/p (normalized electric field value with pressure) are sufficiently large such that plasma is formed on a time scale of 100 ns after which the plasma begins to absorb and reflect a significant amount of the power. The electron densities are on the order of 10$^{13}$-10$^{14}$ cm$^{-3}$ for pressures of 10 to 400 torr in air, N$_{2}$ and argon environments. At these densities, the plasma attenuates the pulse on the order of -40 to -10 dB during peak electric fields. With the use of multi-standard waveguide couplers, a CW low power (a few watts) probing signal is injected into the waveguide structure. Utilizing a 1D plasma model and the transmitted power levels, the temporal evolution of the electron density after the HPM pulse is determined for many microseconds after the pulse. The technique was confirmed by benchmarking with known attachment rates in an air environment along with the 2-body recombination rate of N$_{2}$. This research helps facilitate the understanding of which molecular/atomic species exist during plasma formation from HPM excitation. [Preview Abstract] |
Friday, October 26, 2012 11:29AM - 11:41AM |
B1.00004: Energy Efficient Tunnel Transistors Using Dielectric-Gated Band Engineered Tunnel Junctions Jung Woo, Iman Rezanejad, Rusty Harris Low stand-by power in transistors can be improved with steep sub-threshold tunnel transistors. This work outlines the impact of band-to-band tunneling behavior in InGaAs/Ge that is modulated by HfO$_{2}$ gate on the thin InGaAs side. Numerical simulation of InGaAs/Ge Esaki tunneling heterojunction are modified with dielectric-gating to enhance electrostatic control of the junction while providing gated electrical isolation. The energy band of such structure is simulated for n-type InGaAs in conjunction with p-type germanium. Electrical and band simulation are performed for various thicknesses and doping concentrations. Peak-to-valley current ratio (PVCR) and peak current density (J$_{\mathrm{max}})$ are obtained and compared with other tunneling heterojunctions. Finally, various compositions of InGaAs, which are epitaxially compatible are simulated to maximize the PVCR and J$_{\mathrm{max}}$. [Preview Abstract] |
Friday, October 26, 2012 11:41AM - 11:53AM |
B1.00005: Diffusion MRI/NMR magnetization equations with relaxation times Dilip De, Simon Daniel Bloch-Torrey diffusion magnetization equation ignores relaxation effects of magnetization. Relaxation times are important in any diffusion magnetization studies of perfusion in tissues(Brain and heart specially). Bloch-Torrey equation cannot therefore describe diffusion magnetization in a real-life situation where relaxation effects play a key role, characteristics of tissues under examination. This paper describes derivations of two equations for each of the y and z component diffusion NMR/MRI magnetization (separately) in a rotating frame of reference, where rf B$_{1}$ field is applied along x direction and bias magnetic field(B$_{\mathrm{o}})$ is along z direction. The two equations are expected to further advance the science {\&} technology of Diffusion MRI(DMRI) and diffusion functional MRI(DFMRI). These two techniques are becoming increasingly important in the study and treatment of neurological disorders, especially for the management of patients with acute stroke. It is rapidly becoming a standard for white matter disorders, as diffusion tensor imaging (DTI) can reveal abnormalities in white matter fibre structure and provide models of brain connectivity. [Preview Abstract] |
Friday, October 26, 2012 11:53AM - 12:05PM |
B1.00006: Modification of Richardson-Dushman Equation, variation of thermionic emission constants, temperature variation of workfunction in metals Dilip De, Mathias Ajaeroh Ikechukwu For proper modeling of the thermionic converters and evaluation of efficiency and power output (from given input energy flux) it is necessary to estimate accurately the thermionic currents from the hot emitter surface. In this paper we derive the expression for the work function of a metal as a function of temperature considering thermal expansion and constant number of free electrons. We then modify the Richardson-Dushman equation for thermionic emission and explain the variation of the Thermionic emission constant from metal to metal. This theory of modification of Richarson-Dushman thermionic equation is quite different from that of Seely (1941) and explains better the observed temperature rate of change of work function of tungsten and the variation of thermionic emission constants from metal to metal. [Preview Abstract] |
Friday, October 26, 2012 12:05PM - 12:17PM |
B1.00007: An Innovative Technique of Liquid Purity Analysis and Its Application to Analysis of Water Concentration in Alcohol-Water Mixtures and Studies on Change of Activation Energies of the Mixtures Dilip De, Abdul Aziz Dikko The activation energy of a liquid molecule and hence its viscosity coefficient changes with addition of contaminants to the original liquid. This forms the basis of a new technology for analysis of purity of the liquid. We discovered that concentration of certain contaminants such as water in alcohol or vice versa can be uniquely and accurately determined in a short time (about 10-15 minutes) using a simple and yet innovative technique that only requires measurement of time of flow of the impure liquid (say, water-alcohol mixture) and distilled water through a simple viscometer designed and constructed for this purpose. We find that the viscosity coefficient $\mu $ of alcohol increased almost linearly with water concentration at a rate that depends on the type of alcohol and water concentration. We determined the increase of activation energy of alcohol molecules with increase of water concentration. This increase also depends on type of alcohol. Our detailed investigation on alcohol-water mixtures for both ethyl and methyl alcohol along with discussion on possible future potential application of such a simple, yet very reliable inexpensive technique for liquid purity analysis is presented. A comparison is made of our present method with other methods on the accuracies, problems and reliability of impurity analysis in liquids. A part of the quantum theory of viscosity of liquid mixtures that is in the developmental stage in order to explain some of the observed properties is presented. [Preview Abstract] |
Friday, October 26, 2012 12:17PM - 12:29PM |
B1.00008: A Simple Technique of Liquid Purity Analysis and Its Application to Analysis of Water Concentration in Alcohol-Water Mixtures Dilip De, Abdul Aziz De The change of activation energy of a liquid molecule and hence its viscosity coefficient with addition of contaminants to the original liquid gives rise to a new technology for analysis of purity of the liquid. We discovered that concentration of certain contaminants such as water in alcohol or vice versa can be uniquely and accurately determined in a short time (about 10-15 minutes) using a simple and yet innovative technique that only requires measurement of time of flow of the impure liquid (say, water-alcohol mixture) and distilled water through a simple viscometer. We determined the increase of activation energy of alcohol molecules with increase of water concentration for ethyl and methyl alcohol. Our detailed investigation on the alcohol-water mixtures along with discussion on possible future potential application of the simple and very reliable inexpensive technique for liquid purity analysis is presented. We compared our present method with other methods on the accuracies, problems and reliability of impurity analysis in liquids. We also discuss a part of the quantum theory of viscosity of liquid mixtures that is in the developmental stage. [Preview Abstract] |
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