Bulletin of the American Physical Society
Joint Spring 2012 Meeting of the Texas Sections of the APS and AAPT and Zone 13 of the SPS
Volume 57, Number 2
Thursday–Saturday, March 22–24, 2012; San Angelo, Texas
Session B1: Poster Session |
Hide Abstracts |
Room: Houston Harte University Center UC 205 (WTC Gallery) |
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B1.00001: Compression of Cake Sarah Nason, Brittany Houghton, Timothy Renfro The fall university physics class, at McMurry University, created a compression modulus experiment that even high school students could do. The class came up with this idea after a Young's modulus experiment which involved stretching wire. A question was raised of what would happen if we compressed something else? We created our own Young's modulus experiment, but in a more entertaining way. The experiment involves measuring the height of a cake both before and after a weight has been applied to the cake. We worked to derive the compression modulus by applying weight to a cake. In the end, we had our experimental cake and, ate it too! [Preview Abstract] |
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B1.00002: Numerical Solution of the Boundary Problem for 2D Laplace Equation for Electrostatic Potential in Given Geometry Jared Land, Jeremy Land, Sheharyar Khan This work has been performed as a student project for the upper division Electricity {\&} Magnetism course. The objective was to numerically model the potential grid and the electric field of 2-dimensional capacitors of various geometries and compare them to the experimental data. This has been accomplished by the implementation of finite difference Gauss-Seidel iteration method through the use of the C programming language. Numeric results were then compared to experimental data. The expectations for this project were to successfully simulate the mapping of the experimental potential grid and electric field through the program code. The final results were satisfying since they closely resemble measured potentials. [Preview Abstract] |
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B1.00003: Electromagnetic Accelerator Jared Land The objective of this senior physics student research project was to design a functional electromagnetic accelerator (i.e. railgun), with considerations for size, portability, modularity, and weight. This has been accomplished through practical design application of electromagnetic principles and streamlined construction to study effects of various rail geometries/bore profiles, and projectile design. The railgun has been tested and its efficiency has been studied. [Preview Abstract] |
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B1.00004: Christmas Light Display Arthur Ross, Timothy Renfro The Digital Electronics class at McMurry University created a Christmas light display that toggles the power of different strands of lights, according to what frequencies are played in a song, as an example of an analog to digital circuit. This was accomplished using a BA3830S IC six-band audio filter and six solid-state relays. [Preview Abstract] |
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B1.00005: Explorations in Chaos Physics Armando Maldonado, David Bixler Chaos Theory is an interesting and important branch of physics. Many physical systems, such as weather or fluid flow, exhibit chaotic behavior. Experiments in simple mechanical or electrical systems, as well as simple simulations can be used as methods of studying chaos. Using a mechanical method, we connected a speaker and to a frequency modulator to bounce a table tennis ball. We recorded the ball's motion at different frequencies using a video camera. Using Tracker software we observed it's position versus it's velocity in order to analyze its chaotic behavior. For a simple simulation, we used the visual-based programming in LabView to examine chaotic behavior produced by some non-linear differential equations. Results from both the mechanical system and the simulations will be discussed. For future work, we plan to continue to explore some chaotic simulations and perform a sequence of experiments with an electrical system. Exploring these nonlinear chaotic systems can help us to better understand and model many phenomena found in nature. [Preview Abstract] |
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B1.00006: Angular distribution of bremsstrahlung produced by electrons with initial energies in the range from 10 to 20 keV incident on thick Ag Daniel Gonzales, Brandon Cavness, Scott Williams Experimental results are presented comparing the intensities of the thick-target bremsstrahlung produced by electrons with initial energies ranging from 10 to 20 keV incident on Ag, measured at forward angles in the range of 0 to 55 degrees. When the data are corrected for attenuation due to photon absorption within the target, the results indicate that the detected radiation is distributed anisotropically only at photon energies $k $that are approximately equal to the initial energy of the incident electrons $E_{0}$. The results of our experiments suggest that, as $k/E_{0} \to 0$, the detected radiation essentially becomes isotropic due primarily to the scattering of electrons within the target. Comparison to the theory of Kissel \textit{et al.} [At. Data Nucl. Data Tables \textbf{28}, 381 (1983)] suggests that the angular distribution of bremsstrahlung emitted by electrons incident on thick targets is similar to the angular distribution of bremsstrahlung emitted by electrons incident on free-atom targets only when $k/E_{0} \approx 1$. The experimental data also are in approximate agreement with the angular distribution predictions of the Monte Carlo program PENELOPE. [Preview Abstract] |
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B1.00007: Effects of hydrogen and amorphous carbon on the microwave absorption of carbon nanotubes C.R. Sayavedra, D. Gonzales, B.S. Cavness, S. Williams Plans for experiments studying the effects of hydrogen on the microwave absorption of carbon nanotubes are described, including details concerning the construction of experimental apparatus. Previous studies have shown that carbon nanotubes emit infrared, visible, and ultraviolet radiation under microwave fields. Theoretical studies of this phenomenon have suggested that either vibrational resonances or interactions of the microwaves with metal catalysts are responsible for the observed radiation emission. Our plans involve comparing the emission spectra for unpurified carbon nanotubes synthesized via arc-discharge using nickel and cobalt catalysts with single-walled carbon nanotubes synthesized via chemical vapor deposition using iron catalyst. Additionally, the emission spectra of samples that have undergone hydrogen absorption will be compared to samples that have not as part of an effort to help understand the mechanism(s) responsible for the exothermic reactions observed when nanotubes are irradiated with microwaves. [Preview Abstract] |
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B1.00008: Monitoring metal catalyst content of carbon nanotubes during purification using X-ray fluorescence Brandon Cavness, Joshua Heimbecker, Joe Velasquez, Scott Williams There have been many studies that suggest that catalyst metals in carbon nanotubes (CNTs) may pose a health threat. As there are several potential applications of CNTs in medicine, it is important to be able to quantitatively determine the amount of catalyst contained in a CNT sample. The relative catalyst content of carbon nanotube samples synthesized via arc-discharge has been determined at various stages of the purification process using X-ray fluorescence (XRF) analysis. Purification was achieved by immersing samples in heated nitric acid. The intensities of the nickel K$\alpha $ X-rays were studied to determine the relative catalyst content in the samples. Scanning electron microscopy (SEM) images of purified nanotubes have been compared to the images of a sample that has been irradiated by 0--15keV bremsstrahlung in order to determine if the XRF analysis of the nanotubes is in any way destructive. No obvious structural defects were observed as the result of irradiation. [Preview Abstract] |
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B1.00009: Design of an experiment to study optically-active centers in diamond nanoparticles Ankit Singh, Kunal Tiwari, Suresh Sharma The silicon-vacancy (SiV) and nitrogen-vacancy (NV) complexes in diamond nanoparticles (NPs) are optically active centers, which produce single photon events. These centers may be formed when a silicon atom from the silicon substrate often used in CVD growth or nitrogen from impurities in the feed gas ends up next to a vacancy in the diamond lattice. Because of their stability and high quantum efficiency, SiV and NV centers in diamond NPs are attractive for applications in quantum computing, optics, biotechnology, and medicine. We briefly review our recently published results on diamond NPs, describe the design of an experimental system for carrying out \textit{in-situ} optical spectroscopy and time-correlation measurements, and show preliminary photoluminescence data. [Preview Abstract] |
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B1.00010: Variable Star Search Using ROTSE3 Data Farley Ferrante, Robert Kehoe I present results of a variable star search using data from the Robotic Optical Transient Search Experiment 3 (ROTSE3) telescopes. Variable stars vary in magnitude as seen from Earth due either to changes in the star's luminosity or to changes in the amount of the star's light that reaches Earth. My research is focused on analysis of the time variation of optical light output as recorded in ROTSE 3 images. Specifically, I am attempting to identify short-period variable candidates such as delta Scuti stars, eclipsing binary stars, and contact binary stars. Amplitude variations for these classes of variables are on the order of one magnitude or less with periods on the order of two to five hours. The ROTSE3 telescope sensitivity holds the promise of significantly extending our reach to dimmer objects than previous searches. [Preview Abstract] |
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B1.00011: X-Ray Emission From SN Ia 1885A \& 1986G Melody Packard, E.M. Schlegel, D. Patnaude, S. Katsuda, R. Petre X-ray emission is expected from the explosion and subsequent evolution of a Type Ia supernova. The outgoing shock will run into circumstellar material from early phases of the progenitor's evolution and generate X-ray emission from the interaction. To date, Type Ia supernovae have not been convincingly detected as X-ray sources. A number of remnants in the Milky Way are X-ray sources (eg, SN1006, Tycho). The question of when Type Ia supernovae become X-ray-emitting remnants remains open. We analyze and discuss the available Chandra X-ray Observatory data on two old Type Ia supernovae, SN1885A in M31 and SN1986G in NGC 5128 (= Cen A). [Preview Abstract] |
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B1.00012: Comparison of polar cap potential from AMIE and DMSP Phu Nguyen, Jamie Sterrett, Kevin Pham, Ramon Lopez There exists a voltage across the polar cap due to the electric field generated from the interaction of the solar wind and Earth's magnetic field, known as the cross polar cap potential (CPCP). As satellites fly across the Earth's polar cap, they can indirectly measure the CPCP. The CPCP can also be estimated from measurements of magnetic perturbations on the ground due to electric currents in the ionosphere. We will present a comparison between the CPCP measured from the F13 satellite of the Defense Meteorological Satellite Program (DMSP) and the CPCP calculated from the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) model. The comparisons will be binned into various solar wind conditions to determine the conditions under which the space-based DMSP measurement agrees with the ground-based AMIE model and when they differ. [Preview Abstract] |
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B1.00013: Comparing the ionospheric cross-polar cap potential from an assimilative model to a semi-empirical equation Cezanne Narcisse, Joseph Schinco, Kyle Van Zuiden, Robert Bruntz, Ramon Lopez The cross-polar cap potential (CPCP) in Earth's ionosphere is often used as an indicator of the level of interaction between the solar wind and Earth's magnetic field. Measuring the CPCP directly is often difficult, requiring other approaches. One way of obtaining the CPCP is to combine data from various sources, such as is done with the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) model. Another method is to run computer simulations with real solar wind measurements as input. Recent research indicates that the Weimer (2005) empirical model's CPCP values hit a minimum ``floor'' value for certain solar wind conditions, while the Lyon-Fedder-Mobarry (LFM) simulation finds that the CPCP can continue to drop below that value. We are comparing data from the AMIE model to the Bruntz et al. (2012) formula for the viscous interaction between the solar wind and Earth's magnetosphere, to see whether AMIE also has a floor value, like the Weimer (2005) model, or whether the AMIE CPCP can continue to drop, as is seen in LFM. [Preview Abstract] |
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B1.00014: Study on the KCl Fluorescent X-rays for the MicroX Imaging Rocket Jose A. Rodriguez Lopez, Enectali Figueroa-Feliciano, Steven W. Leman, Steven Kissel The Micro-X High Resolution Microcalorimeter X-ray Imaging Rocket (Micro-X) is an experiment that combines transition-edge-sensors (TES) with a conical imaging mirror, to obtain high-spectral-resolution images of extended X-ray sources. An Fe-55 source will be set on-board to fluoresce a KCl ring to provide calibration lines of 2.62, 2.81, 3.31 and 3.58 keV, these lines will not interfere with the energy band that Micro-X intends to observe, which is from 0.3 to 2.5 keV. An extensive study has been conducted on how the event rate varies when filters of different materials are put in front of the KCl ring. This study was conducted using charge-coupled-devices (CCD), which are commonly used to detect X-ray events with different energies. The study showed that the source plus a single layer of aluminized mylar (thickness 0.01 mm) will provide enough counts of the desired Cl$\alpha$, Cl$\beta$, K$\alpha$, and K$\beta$ lines with little to no events in the 0 to 2 keV energy band. [Preview Abstract] |
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B1.00015: An optimized theory for charged macroions immersed in a molecular electrolyte Damien Villarreal, Zaven Ovanesyan, Marcelo Marucho Widespread work in theory, experiment, and computation has been carried out to gain a fundamental understanding of the rich, yet sometimes counterintuitive, behavior of charged macroions immersed in a molecular electrolyte. Due to strong interactions with the macroion surface and with each other, screening Z-ions are not positioned randomly in 3D space, but form a strongly correlated liquid on the surface of the macroion. Hence, a detailed knowledge of the structural arrangement g(r) of ions and water molecules in the vicinity of a macroion is of crucial importance to get a microscopic understanding of polyelectrolyte systems. To achieve this, novel computational methods are required to treat the solvent effects on macroions at the atomic level. In this poster, we present an approximation optimized for integral equation theories to compute g(r) for molecular fluids. It is especially designed to take advantage and eliminate deficiencies present in old, but still used approximations, including HNC and PY. As a preliminary test, we calculate correlation functions g(r) for spherical nanoparticles immersed in an aqueous electrolyte, achieving a compromise between accuracy and computational cost without suffering the limitations demanded by full atomistic simulation calculations. [Preview Abstract] |
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B1.00016: Nano-mechanics of prostate cancer cells on nano-scaffolds Lyndon Bastatas, James Matthews, Jood Hashem, Souad Sennoune, Raul Zanguillan-Martinez, Soyeun Park We investigated the nano-mechanics of lowly metastatic (LNCaP) and highly metastatic (CL-1) prostate cancer cells cultured on nano-scaffolds by performing AFM indenting experiments. The functionalized nano-scaffolds allowed us to control the cell-to-substrate adhesion, hence the focal adhesion. We measured the elastic moduli at the center of the cell at different adhesion sizes of the nano-arrays. The obtained mechanical signature indicates that smaller focal adhesion could elicit apoptosis. This study, in general, demonstrates that nano-scaffolds could be used as a tool for adhesion assay and as a~metastatic indicator. [Preview Abstract] |
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B1.00017: Absorbance Differentiation of Burned and Normal Tissue by the Addition of Glycerol Chuan-I. Chang, Hector de Pedro, Faranak Zarnani, Ahamed Idris, R. Glosser Minimizing the removal of healthy/recoverable tissue would significantly increase the chances of the patients' survival. The purpose is to be able to optically differentiate between burned and normal tissue with the addition of glycerol. Under normal conditions (without glycerol), the absorption coefficient is large, which means there is a large amount of absorption in the tissue. Glycerol decreases the absorption coefficient by reducing the cell size as well as providing a more uniform index of refraction in the interstitial environment. A lower overall absorption will reveal absorption peaks specific to the differentiation of the tissue. Results will be presented on the day of the conference. [Preview Abstract] |
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B1.00018: Absolute Theory of Relativity Florentin Smarandache We redo Einstein's thought experiment with atomic clocks from the Special Theory of Relativity. Herein we consider an absolute time and an absolute space but no ultimate speed, and we call it Absolute Theory of Relativity (ATR). Our ATR is free from time dilation, space contraction, relative simultaneity, and relativistic paradoxes. [Preview Abstract] |
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B1.00019: ABSTRACT WITHDRAWN |
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B1.00020: Pressure induced structural transitions in Lead Chalcogenides and its influence on thermoelectric properties John Petersen, Michael Spinks, Pablo Borges, Luisa Scolfaro Lead chalcogenides, most notably PbTe and PbSe, have become an active area of research due to their thermoelectric (TE) properties. The high figure of merit (ZT) of these materials has brought much attention to them, due to their ability to convert waste heat into electricity, with a possible application being in engine exhaust. Here, we examine the effects of altering the lattice parameter on total ground state energy and the band gap using first principles calculations performed within Density Functional Theory and the Projector Augmented Wave approach and the Vienna Ab-initio Simulation Package (VASP-PAW) code. Both PbTe and PbSe, in NaCl, orthorhombic, and CsCl structures are considered. It is found that altering the lattice parameter, which is analogous to applying external pressure on the material experimentally, has notable effects on both ground state energy and the band gap. The implications of this behavior in the TE properties of these materials are analyzed. [Preview Abstract] |
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B1.00021: ABSTRACT WITHDRAWN |
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B1.00022: ABSTRACT WITHDRAWN |
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B1.00023: First-Principles Study of Properties of the Oxidized Cu(110) and Cu(111) Surfaces Antoine Olenga, N.G. Fazleev The study of adsorption of oxygen on transition metal surfaces is important for the understanding of oxidation, heterogeneous catalysis, and metal corrosion. In this work we have studied from first principles the changes of electronic properties of the Cu(110) and Cu(111) surfaces due to oxygen adsorption. Especially, we have focused on studies of changes in the work function, electronic density, interlayer spacing, density of states and band structure with oxygen coverage. Calculations of electronic properties from first principles have been also performed for the (110) and (111) surfaces of Cu2O to use for comparison. The first-principles calculations in this work have been performed on the basis of the Density Functional Theory and using DMOl3 code. The obtained theoretical results have been compared with available experimental data. [Preview Abstract] |
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B1.00024: ABSTRACT WITHDRAWN |
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B1.00025: QMSA Measurements of III-V Heterostructures on Silicon Thiess Cunningham, Richard Hill, Man Hoi Wong, Ravi Droopad There is widespread consensus that high mobility III-V channel materials will enable increased performance and reduced power consumption at scaled geometries [1]. The industry is currently targeting the 11 nm technology node for their introduction. One of the most significant challenges is the heterointegration of III-V channel materials on Si substrates, which is essential to access large diameter cost effective silicon substrates. We compare carrier transport of MBE grown InGaAs/InAlAs HEMTs on InP and Si substrates using Quantitative Mobility Spectrum Analysis (QMSA). Measurements were taken to determine the effect of epitaxial defects on channel transport and buffer leakage. The continued scaling of Si CMOS devices has reached the point where, alternative solutions to the conventional MOSFET device need to be found. One solution being considered is the use of III-V compound semiconductors as the channel materials. However, the requirement is that these materials need to be epitaxially integrated onto silicon and be able to withstand the thermal budget in the various CMOS processing modules. In this presentation, we will present the electrical characterization of MBE grown III-V InGaAs/InAlAs heterostructures on silicon. Transport measurements at various temperatures ranging from 10k-room temperature in magnetic fields from 0-10T. From these measurements, QMSA of the data is carried out to the densities and mobilities of the conducting and buffer layers. [Preview Abstract] |
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B1.00026: Hydroelectric Generator Daniel Zipprian The idea behind a hydro electric generator is to have a large potential well of water that you can be controlled to be able to convert into kinetic energy. The kinetic energy is from the flow of water which is directed towards some kind of turbine. In turn the kinetic energy is turned into mechanical energy. The turning of the turbine rotates the rotor part of the generator, and the stator remains stationary. Induction is caused when the rotor is rotating around the stator. This is caused when a magnetic field interacts with a wire causing the electrons inside the wire to face in the same direction. Once the magnetic field begins to move the electrons start to flow through the wire creating current. For this to work the direction of the magnetic field has to be perpendicular to the direction of the coils of wires. For my design I plan to funnel the flow of water into a nozzle which will be aimed towards my turbine. The turbine with be connected to a shaft that will be connected to my rotor. The rotor I designed uses a brake router for the surface to hold me magnets. The system will be vertical, with the rotor as the highest part on the generator and the turbine at the bottom. The magnets will be facing downwards with the magnetic field going in a vertical direction. The stator of my generator will be the coils which will sit on top of a metal ring that have the ability to rise or low to match the height of the brake router. [Preview Abstract] |
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B1.00027: Comparing MRT scores of introductory STEM classes with a higher-level physics class Elijah Murphy, Thad Loftis, Ximena Cid, Ramon Lopez Science, technology, engineering, and math (STEM) classes require students to use mental spatial skills and reasoning. We can objectively measure a student's mental spatial skills with a Mental Rotation Test (MRT). We compared MRT scores for students in introductory chemistry, math, and physics classes against scores for students in an upper level physics course and found that the upper level physics students scored better on the MRT on average than the introductory students. We have also found a small correlation between students' performance in the upper lever class, as measured by final grades, and the students' MRT scores. [Preview Abstract] |
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B1.00028: The Influence of Photolysis Rate Constants in Ozone Production for the Paso del Norte Region Fernando Becerra, Rosa Fitzgerald In this research work we are focusing on understanding the relationship between photolysis rates and the photochemical ozone changes observed in the Paso del Norte region. The city of El Paso, Texas together with Ciudad Juarez, Mexico, forms the largest contiguous bi-national metropolitan area. This region suffers year-round ozone pollution events, and a better understanding is needed to mitigate them. Previous studies have found that ambient ozone concentrations tend to be higher on weekends rather than on weekdays, this phenomenon being referred to, as the ``weekend effect.'' If the ozone standard is exceeded more frequently on weekends, then this phenomenon must be considered in the design of ozone control strategies. In this work we investigate some of the most representative weekend ozone episodes at El Paso, TX, during the years 2009, 2010 and 2011 using the ozone photolysis rates. In this research the TUV radiative-transfer model is used to calculate the local photolysis rates and a UV MFRSR instrument is used to obtain experimental parameters. Seasonal variations and the weekday-weekend effect is studied. The results of this research will help to understand the underlying behavior of the photolysis rate constants when different atmospheric conditions are present. [Preview Abstract] |
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