Bulletin of the American Physical Society
APS April Meeting 2011
Volume 56, Number 4
Saturday–Tuesday, April 30–May 3 2011; Anaheim, California
Session D1: Poster Session I (2:00-5:00PM) |
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Sponsoring Units: APS Room: Imperial/Regal Rooms |
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D1.00001: UNDERGRADUATE RESEARCH |
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D1.00002: Intonation and compensation of fretted string instruments Gabriele Varieschi, Christina Gower We discuss theoretical and physical models that are useful for analyzing the intonation of musical instruments such as guitars and mandolins and can be used to improve the tuning on these instruments. The placement of frets on the fingerboard is designed according to mathematical rules and the assumption of an ideal string. The analysis becomes more complicated when we include the effects of deformation of the string and inharmonicity due to other string characteristics. As a consequence, perfect intonation of all the notes on the instrument cannot be achieved, but complex compensation procedures can be introduced to minimize the problem. To test the validity of these procedures, we performed extensive measurements using standard monochord sonometers and other acoustical devices, confirming the correctness of our theoretical models. These experimental activities can be integrated into acoustics courses and laboratories and can become a more advanced version of basic experiments with monochords and sonometers. [Preview Abstract] |
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D1.00003: Proportional-Integral-Derivative (PID) Temperature Control and Data Acquisition System for Faraday Filter based Sodium Spectrometer Vardan Semerjyan, Tao Yuan Sodium (Na) Faraday filters based spectrometer is a relatively new instrument to study sodium nightglow as well as sodium and oxygen chemistry in the mesopause region. Successful spectrometer measurement demands highly accurate control of filter temperature. The ideal, long-term operation site for the Na spectrometer is an isolated location with minimum nocturnal sky background. Thus, the remote control of the filter temperature is a requirement for such operation, whereas current temperature controllers can only be operated manually. The proposed approach is aimed to not only enhance the temperature control, but also achieve spectrometer's remote and autonomous operation. In the meantime, the redesign should relief the burden of the cost for multi temperature controllers. The program will give to the operator flexibility in setting the operation temperatures of the Faraday filters, monitoring the temperature variations, and logging the data during the operation. Research will make diligent efforts to attach preliminary data analysis subroutine to the main control program. The real-time observation results will be posted online after the observation is completed. This approach also can be a good substitute for the temperature control system currently used to run the Lidar system at Utah State University(USU). [Preview Abstract] |
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D1.00004: Optical Properties of Aqueous Solutions Present in Planetary Atmospheres Determined from Laboratory Attenuated Total Reflection (ATR) Measurements Bhuwan Ghimire, Kent F. Palmer, Besjana Nikoci, Kristen Thurman Liquid aqueous solutions (e.g. sulfuric acid solutions) appear as droplets in the Earth's atmosphere and in other planetary atmospheres. Their presence affects the transfer of radiation within the atmosphere and has the potential to alter a planet's climate. We present the infrared optical constants of several aqueous solutions obtained from ATR intensity measurements using a Fourier transform infrared spectrometer (FTIR). We discuss the experimental procedures used to reduce errors caused by the partial polarization of the spectrometer beam due to mirror reflections. [Preview Abstract] |
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D1.00005: Raman Study of the Verwey Transition in Magnetite (Fe$_{3}$O$_{4})$ at High Pressure and Low Temperature: Effect of Aluminum Doping Zhanna Shirshikova, Lev Gasparov, V. Struzhkin, A. Gavriliuk, H. Berger Raman spectra of pure and doped magnetite provide a set of markers allowing one to study how the Verwey transition in magnetite changes with the change of pressure. At ambient pressure Verwey transition temperature, T$_{v}$, of the single crystals of magnetite, Fe$_{3}$O$_{4}$, is determined to be 123K. High-pressure experiment indicates strong dependence of the change of pressure vs. change in the Verwey transition temperature$_{ }$on the amount of impurities: for pure Fe$_{3}$O$_{4}$ the change is -0.2 GPa/K; for doped iron, Fe$_{2.98}$Al$_{0.02}$O$_{4}$, the change is -0.09 GPa/K. Aluminum-doped magnetite (Fe$_{2.98}$Al$_{0.02}$O$_{4})$ where Al substitutes Fe$^{+2}$ and Fe$^{+3}$ atoms, represents a 2{\%} aluminum doping, which shifts the Verwey transition temperature to T$_{v}$=118.5K. The rate with which the Verwey temperature decreases with pressure is further discussed based on the molar specific heat measurements. [Preview Abstract] |
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D1.00006: Investigation of Anisotropic Magnetic Properties in (BIPB)$_{2}$SR$_{2}$CACU$_{2}$O$_{8}$ Superconducting Crystals Rodolfo Lopez, Jr., Steven Lee, Gregorio Franco, Jr., Josh Casara, Lu Zhang High quality single crystals of (BiPb)$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8}$ were grown by a self flux method. The superconducting transition temperatures are 92-96K with transition widths of 2-4K. Hysteresis loops and rates of magnetic relaxation were measured at different field orientations to study the critical state behavior and thermally activated flux creep. The large magnetic relaxation exhibits a logarithmic time-dependence indicative of substantial flux creep due to thermally-induced flux motion. Critical current densities were analyzed using the extended 2-dimensional Bean's Model at high field remanence. These results demonstrate a relatively strong anisotropy in this material. The extended flux creep model was employed to interpret the field dependent relaxation rates. The thermally activated energy barriers indicate that the flux creep is parallel to the ab plane in both H$\vert \vert $c and H$\bot $c configurations. [Preview Abstract] |
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D1.00007: How perfect is a neutron fluid? Dan Fu, Aram Mekjian A perfect fluid has the lowest shear viscosity allowed by the uncertainty principle which also involves a study of the entropy density. Kinetic theory based on the Chapman-Enskog approach is used to obtain both the classical and quantum values of the viscosity of a neutron fluid. The interaction potential used in the study is an attractive square well with an inner hard core. The classical scattering angle and the phase shifts are calculated for this potential. The entropy density is based on the Sakur-Tetrode law plus corrections coming from two particle interactions obtained from a Beth-Ulhenbeck expression. Using these results for the viscosity and entropy density, the perfect fluid aspects of a neutron fluid are addressed. The viscosity to number density is also proportional to Planck's constant. The proportionality constant, called alpha, is found to be of the order of 1 in a quantum description of a neutron fluid. The value of the viscosity for a neutron fluid is near its unitary limit. For air at STP alpha is 7500, for water alpha is 300. The results for neutron matter suggest a near perfect fluid behavior. [Preview Abstract] |
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D1.00008: A Computational Study of Parabolic Encounters of Black Holes and Neutron Stars Linda Holyoke, Erik Schnetter There is still uncertainty regarding the progenitors of Short Gamma-Ray Bursts (SGRB). One of the many proposed models is based on parabolic encounters between black holes and compact stars (such as neutron stars) within globular clusters. A recent Newtonian computational study supports this SGRB mechanism (Lee et al., ApJ 720, 953 (2010)). With the motivation that accuracy will increase when general relativity is taken into account, we present a study where we perform fully relativistic simulations. We compare results to the Newtonian study and assess the validity of the proposed mechanism. Our current results indicate a potential SGRB production; we observe formation of a neutron star accretion disk with a mass and estimated lifetime not inconsistent with the requirements for an SGRB. Future work will improve our initial setup generation, will follow the simulated system for a longer time, and will explore a larger set of initial parameters such as masses and spins to be able to estimate event rates. [Preview Abstract] |
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D1.00009: Pressure Dependence Studies on UTA GEM Based Digital Hadron Calorimeter Edwin Baldelomar The University of Texas at Arlington High Energy Physics group has been developing a Digital Hadron Calorimeter (DHCAL) for the future Linear Collider (LC) using the Gas Electron Multiplier (GEM) technology. The group has built several prototype chambers of various dimensions up to 30cmx30cm. The prototypes have been successful in measuring charges deposited traversing incident particles from cosmic rays and radioactive sources. The data was taken using the 13bit kPIX ASIC chips. This presentation includes the pressure dependence of the GEM chamber gain and corresponding correction factors for chamber responses to cosmic rayds and Fe 55 data. The pressure dependence will be compared against monte carlo simulations using the GEANT. In addition, the significance of the results to the future GEM DHCAL for use in the future linear collider experiments and other purposes, such as medical imaging and home land security, will be presented. [Preview Abstract] |
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D1.00010: PHYSICS EDUCATION |
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D1.00011: Partners in Physics with Colorado School of Mines' Society of Physics Students Shirley Moore, Matthew Stilwell, Zach Boerner The Colorado School of Mines (CSM) Society of Physics Students (SPS) revitalized in 2008 and has since blown up with outreach activity, incorporating all age levels into our programs. In Spring 2010, CSM SPS launched a new program called Partners in Physics. Students from Golden High School came to CSM where they had a college-level lesson on standing waves and their applications. These students then joined volunteers from CSM in teaching local elementary school students about standing waves beginning with a science show. The CSM and high school students then helped the children to build make-and-take demonstrations incorporating waves. This year, rockets are the theme for Partners in Physics and we began with demonstrations with local middle school students. In Spring 2011, CSM SPS will be teaching elementary school students about projectile motion and model rockets along with these middle school students. [Preview Abstract] |
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D1.00012: Post PhysTEC at Arkansas, Graduation Numbers Stable, Student Enthusiasm High Gay Stewart At the University of Arkansas in Fayetteville, active learning in the content coursework has been key to the recruitment of MAJORS and TEACHERS. We have supported the process through the use of apprentice teachers, one learning assistant model. Master teachers have also aided in the recruitment, and true partnerships with local schools have allowed us to provide improved support to our graduates through the induction years. The topics of this talk will be how did we create these programs and how did we institutionalize them? [Preview Abstract] |
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D1.00013: Electricity and Magnetism Self-Testing and Test Construction Tool Gay Stewart, John Stewart This talk presents an online resource for teaching and evaluating introductory electricity and magnetism classes. The resource contains a library of highly characterized, multiple-choice, conceptual and quantitative electricity and magnetism problems and solutions all linked to a free online textbook. The library contains over 1000 classroom tested problems. Each problem is characterized by the complexity of its solution and by the fundamental intellectual steps found in the solution. Exam construction, administration, and analysis tools are provided through the resource's website. Problems may be downloaded for use in exams or as clicker questions. Instructors may also design and administer assignments online. A self-testing tool is provided for students or instructors, an excellent tool for brushing up on conceptual electricity and magnetism. Conceptual inventory scores produced by the site are normed against the Conceptual Survey in Electricity and Magnetism. There is no cost associated with using any of the facilities of the site and you can begin to use the site immediately. Supported by NSF - DUE 0535928. Site address http://physinfo.uark.edu/physicsonline. [Preview Abstract] |
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D1.00014: PLASMA PHYSICS |
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D1.00015: Emission Structures and Bursty Events in WIRX D. Craig, C. Adams, D. Blasing, M. McMillan We report on observations and analysis of ICCD images taken in the Wheaton Impulsive Reconnection Experiment (WIRX). The experiment is composed of two parallel electrodes, linked by a magnetic arcade generated by a coil surrounding the electrodes. Images reveal a plasma ball which expands from the arcade and an elongated emission feature connected to one end of the arcade. These are interpreted using magnetic field line tracing and an ad hoc model of the plasma current. Under some driving conditions, bursty events appear which are similar in some ways to reconnection events in other plasmas. Work is ongoing to determine if these events involve reconnection. ICCD camera images suggest a bursty emission of plasma from the arcade during these events. Photodiode cameras and magnetic probes are under development to better characterize the evolution of the arcade in time and space and to look for signatures of reconnection. Work supported by U.S.D.O.E. grant DE-FG02-08ER55002. [Preview Abstract] |
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D1.00016: Proton Beam Fast Ignition Fusion: Synergy of Weibel and Rayleigh-Taylor Instabilities V. Alexander Stefan The proton beam generation and focusing in fast ignition\footnote{ M. Roth et al , Phys. Rev. Lett. 86, 436 (2001); M. Tabak et al, Phys. Plasmas 1 (5), 1626 (1994). } inertial confinement fusion\footnote{ K. .A. Brueckner and V. Stefan, \textit{Possibility of Anomalous Plasma Effects in~Heavy-Ion Beam Fusion},~Bul. Am. Phys. Soc., 27, 8 (1982).} is studied. The spatial and energy spread of the proton beam generated in a laser-solid interaction is increased due to the synergy of Weibel and Rayleigh-Taylor instabilities.\footnote{ V. Alexander Stefan, \textit{Nonlinear Electromagnetic Radiation Plasma Interactions}, (S-U-Press, 2008)} The focal spot radius can reach 100$\mu $m, which is nearly an order of magnitude larger than the optimal value. The energy spread decreases the beam deposition energy in the focal spot. Under these conditions, ignition of a precompressed DT fuel is achieved with the beam powers much higher than the values presently in consideration. [Preview Abstract] |
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D1.00017: Compression of a stationary FRC plasma by an imploding Xenon plasma liner George Votroubek, John Slough The Plasma Liner Compression (PLC) Experiment is designed to explore the creation of a magnetized high energy density (HED) plasma via plasma liner compression of a magnetized plasmoid. The magnetized plasmoid employed in this experiment is the Field Reversed Configuration (FRC) plasma, a simply connected, high-beta, compact torriod. The closed poloidal field of the FRC inhibits thermal losses as the object is compressed, which in turn reduces the compression required to reach fusion conditions. In the PLC experiment, a stationary FRC target is created by merging two theta-pinch FRCs formed on opposite sides of a cylindrical chamber and accelerated toward the center. The center of the experiment is comprised of a larger cylindrical chamber where a Xenon plasma liner is formed within a few centimeters of the vacuum wall. The source FRCs collide, merge and become stationary in the high vacuum region interior to the Xenon liner. The plasma liner is then imploded via high voltage theta-pinch coils, compressing and heating the magnetized plasmoid. Dynamics of liner formation, FRC target formation, and liner-on-FRC compression results will be discussed. [Preview Abstract] |
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D1.00018: ITER Plasma at Electron Cyclotron Frequency Domain: Stimulated Raman Scattering off Gould-Trivelpiece Modes and Generation of Suprathermal Electrons and Energetic Ions V. Alexander Stefan Stimulated Raman scattering in the electron cyclotron frequency range\footnote{R. Prater et. al., APS-DPP-2009, (BAPS.2009.DPP.NO4.11).} of the X-Mode and O-Mode driver with the ITER plasma leads to the ``tail heating'' via the generation of suprathermal electrons and energetic ions. The scattering off Trivelpiece-Gould (T-G) modes is studied for the gyrotron frequency of 170GHz; X-Mode and O-Mode power of 24 MW CW; on-axis B-field of 10T. The synergy between the two-plasmon decay\footnote{ V. Alexander STEFAN, APS-DPP-2009, (K1.00028); APS-DPP-2010, (DPP10-2010-000167).} and Raman scattering is analyzed in reference to the bulk plasma heating.\footnote{ V. Alexander STEFAN, \textit{Nonlinear Electromagnetic Radiation Plasma Interactions}, (S-U-Press, 2008).} [Preview Abstract] |
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D1.00019: Study of electron acceleration in the reconnection current sheet via TS-4 particle trajectory calculations Patrick Copinger, Michiaki Inomoto, Yasushi Ono Particle acceleration during reconnection has remained a challenging problem in the study of solar flares in part due to a lack of direct measurements. The TS-4 (Tokyo University Spherical Torus) device, however, allows for in depth reconnection study through the merging of two plasma tori. Measurements of particle acceleration phenomena such as energy analysis in the TS-4 are difficult compared to measurements of the 2-D magnetic probe array on the R-Z plane. Hence, particle trajectories are simulated using magnetic probe data to provide a preliminary examination of particle acceleration during reconnection. Electron acceleration in the reconnection current sheet is found for a number of configurations. Last, future experimental direction is discussed. [Preview Abstract] |
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D1.00020: Plasma and gas dynamics in microplasmas: influence of secondary emission Manish Jugroot Understanding small spaces is highly interesting as the complexity of micro-technology systems increases. A self-consistent model of plasma and gas dynamics is applied to microplasmas. Fluid equations of the fully self-consistent model are described with emphasis on the close coupling among the plasma, the fluid and the electric field. The microplasmas are studied from an initial cloud and the momentum and energy transfer are investigated for these discharges. Due to the proximity of walls and electrodes, secondary emission appears as a critical parameter and several characteristic values are parameterized. Gas heating and depletion initiation are observed, highlighting the close interaction between: the fluid and the ionized gas (volume effects) and secondary emission (surface effects) in governing the evolution of microplasmas. [Preview Abstract] |
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D1.00021: Plasma Outages in Pulsed, High-Power RF Hydrogen Ion Sources Martin Stockli, Baoxi Han, Syd Murray, Terry Pennisi, Chip Piller, Manuel Santana, Robert Welton Pulsed, high-power RF ion sources are needed to produce copious amounts of negative H- ions for high-power accelerators with charge-changing injection schemes. When increasing the RF power, the plasma inductance changes the RF resonance, which drifts away from the low-power resonance. When the RF circuit is tuned to maximize the (pulsed) plasma power, the (off- resonance) power at the beginning of the pulse is reduced. If the induced electric fields fall below the breakdown strength of the hydrogen gas, the plasma fails to develop. This can be avoided with a compromise tune and/or by increasing the inductance of the resonant circuit. However, the breakdown strength of the hydrogen gas increases with time due to the gradual decrease of the electron-rich plasma impurities, which causes plasma outages after weeks of reliable operation. In this paper we discuss the success of different mitigations that were tested and implemented to overcome this fundamental problem of pulsed, high-power RF hydrogen ion sources. [Preview Abstract] |
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D1.00022: Numerical study of dominant transport channels in the pedestal region of H-mode tokamak plasmas A. Pankin, J. Cary, A. Hakim, S. Kruger, A. Pletzer, S. Shasharina, S. Vadlamani, R. Groebner, J. Callen, R. Cohen, T. Rognlien The confinement of H-mode plasmas strongly depends on the the H- mode pedestal structure. The pedestal provides the boundary conditions for the hot core tokamak region and determines the stability properties of the plasma edge. The structure of H-mode pedestal depends on many factors such heating of the plasma core, neutral fueling, recycling and particle and thermal transport. It is important to elucidate the primary mechanisms that are responsible for the pedestal structure in order to optimize the tokamak performance, avoid disruptions and large scale instabilities such as NTM and ELMs. In this study, the FACETS code is used to test several models for anomalous, paleoclassical and neoclassical transport in the plasma edge of tokamaks. The FACETS code is a new whole-device integrated modeling code that advances plasma profiles in time using a selection of transport models and models for heating and particle sources. The simulation results are compared with experimental measurements from major US tokamaks such DIII-D. These validation efforts allows to discriminate between different models for transport in the different regions of the H-mode pedestal.\newline $\ ^*$ This research is supported by US Department of Energy. [Preview Abstract] |
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D1.00023: TESTS OF PHYSICAL LAWS |
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D1.00024: On the Critical Analysis of Classical Electrodynamics Temur Z. Kalanov Critical analysis of classical electrodynamics within the correct methodological basis - unity of formal logic and of rational dialectics - is proposed. The main result of analysis is as follows: 1) quantitative (mathematical) relations proposed by Faraday, Maxwell, Lorentz, and others have following qualitative determinacy: \textit{(field) = (source of field)}; 2) from the formal-logical point of view, the left-hand and right-hand parts of these quantitative relations must belong to one and only one of the following qualitative determinacy: \textit{(field) = (field)} or \textit{(source of field) = (source of field)} expressing the law of the identity of the object; 3) Faraday's, Maxwell's, and Lorentz's quantitative relations did not belong to the qualitative relations \textit{(field) = (field)} or \textit{(source of field) = (source of field)}. Consequently, Faraday's, Maxwell's, and Lorentz's relations contradict the logical law of identity. Thus, classical electrodynamics is an erroneous theory, and it should be replaced by a correct theory. [Preview Abstract] |
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D1.00025: Element No.155 - an Equal Member of the Periodic Table of Elements Albert Khazan Properties of the elements of the Periodic Table of Elements were studied on the basis of experimental and theoretical data with use of the parameters of a suggested element No.155. The dependency ``atomic mass - number in the Table'' showed that the calculated equations of the intervals of elements No.1-54, No.55-118, and No.119-155 have a very high probability of 0.99-1.0, as well as the calculated line of the trend in No.1-118. Additionally, the other dependencies were studied for the intervals No.1-155 and No.1-104 (R$^{2}$=0.9997; 0.999): the nucleus' radius -- the number of the nucleons; the electrons' critical energy -- the number of the protons; the nucleus' coupling energy -- the mass number; the number of the neutrons -- the nucleus' charge; the ionization potential of the atom -- the nucleus' charge. The region of the ultimate high coupling energy of the nuclei in the Table (behind which the nuclei become instable) was calculated with use of the parameters of element No.155. The obtained results manifest: element No.155 should be considered as an equal member of the Periodic Table (Khazan A. Upper Limit in Mendeleev's Periodic Table -- Element No.155. Svenska fysikarkivet, Stockholm, 2010). [Preview Abstract] |
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D1.00026: Scalar Potential Model of photon diffraction John Hodge Some observations of light are inconsistent with a wave--like model. Other observations of light are inconsistent with a traditional particle--like model. A single model of light has remained a mystery. Newton's speculations, Democritus's speculations, the Bohm interpretation, and the fractal philosophy are combined with the cosmological Scalar Potential Model (SPM). The resulting model of photon structure and dynamics is tested by a toy computer experiment. The simulations included light from a distance and Young's experiment. The patterns on the screens showed diffraction wave patterns fit by the Fresnel equation. The model is consistent with the Afshar experiment and with the concepts of Bohmian mechanics. [Preview Abstract] |
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D1.00027: Entanglement Disproved Jeffrey Boyd The double slit and Innsbruck experiments are thought to be the premier experiments establishing the need for the idea of ``non-locality'' in quantum mechanics. In the Innsbruck experiments it is said that two photons at a distance are ``entangled'' without there being any means of communication between them. But the interpretation of these experiments are based on the incorrect idea of wave particle duality. According to the Theory of Elementary Waves (TEW) waves are independent of particles. Waves are ubiquitous in nature. In the Innsbruck experiments two waves traveling at the speed of light in opposite directions impinge on the photon source from the two fiberoptic cables. The waves pass through the source. Wave interference is spread over a wide distance: from one polarizer to the other. This stimulates the emission of a photon pair such that, when detected at a polarizer at angle $\theta $1 and another polarizer at angle $\theta $2, the probability density is sin$^2$($\theta $1 -- $\theta $2). This is true for any $\theta $1 and $\theta $2, and it doesn't matter when the polarizers are rotated. Thus local wave interference accounts for the experimental results, without any need for the exotic theory of ``entanglement.'' See http://Elwave.org [Preview Abstract] |
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D1.00028: Electron Impact Ionization of the K-shell Atoms: a comparative study Bidhan Saha The electron impact ionization (EII) is of fundamental importance in understanding the physics of the collision process involving a many-electron systems involving neutral and ionic targets. EII cross sections (EIICS) are needed in many fields such as astrophysics, atomic, biological, chemical, molecular and plasma physics etc. for various targets over a wide range of projectile energies. Using various models such as the MBELL, XCVTS, GKLV and MUIBED models [1], the predictions of these models are compared with the available EIICS data as well as other theoretical results. For the $K-$shell ionization, the calculated cross sections agree very nicely with the experimental findings. Details will be presented on the conference. \\[4pt] [1] A. K. F. Haque, M. A. Uddin, M. Shahjahan, M. R. Talukder, A. K. Basak, B. C. Saha, in Advances in Quantum Chemistry, Vol 61, 2011 (in press). [Preview Abstract] |
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D1.00029: An experimental search for the electron Electric Dipole Moment in Gadolinium Gallium Garnet Young Jin Kim, Chen-Yu Liu A discovery of a permanent electric dipole moment of the electron (eEDM) would provide crucial information about the nature of T-violation and imply new sources of CP-violation beyond the Standard Model. While the leading experimental technique used to measure EDM is based on the nuclear magnetic resonance, we are pursuing research that would improve the present experimental limit of the eEDM using a new technique in solid-state systems at low temperatures. The experiment uses a paramagnetic insulator Gadolinium Gallium Garnet with a large magnetic response. The presence of the eEDM leads to a finite magnetization when the garnet sample is subjected to a strong electric field. The resulting magnetization can be measured using the Superconducting Quantum Interference Device (SQUID) as a sensitive magnetometer. In this talk, we will discuss the progress to control the systematic effects and improve the sensitivity. The major efforts include the design and implementation of a 24-bit data acquisition system with ultra-low level of channel crosstalk, and the control of the high voltage drift from the supply. With these considerable progresses, we report our first background-free experimental limit of the eEDM on the order of 10$^{-24}$ e.cm . [Preview Abstract] |
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D1.00030: Calculating the Photon Polarization Tensor Without Renormalizing Kenneth Brand In this presentation, the Quantum Electrodynamics photon polarization tensor is evaluated in momentum space using new techniques. The resulting polarization tensor is automatically gauge invariant. No divergent quantities are encountered; there is no need to renormalize. Our tensor agrees with the standard renormalized QED tensor. The key innovations in these calculations are: 1)Reducing the number of integration variables at a stage farther into the calculations than is usual, 2) Separating the scalar propagator into real and imaginary parts, and 3)Regularizing some integrals by employing weighting functions that are the fourier transforms of support based delta functions. [Preview Abstract] |
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D1.00031: New laboratory tests of relativistic gravity using dipole waves Franklin Felber The most advanced gravity gradiometers and resonant transducers are now becoming capable of measuring dipole gravity waves produced by the most advanced periodic mass quadrupoles, like high-energy-density flywheels and teravolt-scale colliders. Laboratory tests of general relativity at relativistic speeds through measurements of dipole gravity waves in the source region are proposed.\footnote{F. Felber, http://arxiv.org/abs/1002.0351 (2010).} A NASA G2 flywheel module with a modified rotor can produce a post-Newtonian dc bias signal at a gradiometer up to 1 mE. At peak luminosity, the repulsive dipole impulses of proton bunches at the LHC can produce an rms velocity of a high-$Q$ transducer surface up to 4 $\mu $m/s at 31.6 MHz. The LHC test can be performed offline, without interfering with normal operations, and could provide the first evidence of repulsive gravity at relativistic speeds. [Preview Abstract] |
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D1.00032: A null experiment shows that preferred frame effects do not exist for tunneling photons with superluminal group velocity George Soli An experimental method, for demonstrating that superluminal group velocity, associated with tunneling photons, is not superluminal energy propagation, is presented. The method measures possible preferred frame effects that would exist for superluminal energy propagation. In Lorentz invariant theories, causal superluminal energy propagation in one reference frame is acausal in other frames. But Lorentz-violating theories have a preferred frame in which causal evolution is defined and superluminal propagation becomes causal in all reference frames. Null measurements show that preferred frame effects do not exist relative to the Cosmic Microwave Background rest frame for tunneling photons with superluminal group velocity. [Preview Abstract] |
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D1.00033: A Galilean Transformation Consistent with Special Relativity Frank Tangherlini As shown earlier [1], a linear transformation with the same form for the spatial coordinates as the Lorentz transformation (LT) that keeps simultaneity invariant and allows for time dilation, predicts the same results as the LT for the out-and- back speed of light, as well as numerous other tests of special relativity. Using this transformation, which is now interpreted as involving external synchronization, rather than the superluminal synchronization discussed previously [1], it will be shown that two frames moving uniformly with speed $v$, but in opposite directions relative to an inertial frame, can be related to one another by a Galilean transformation with a relative velocity $V=2v/(1-(v/c)^2$, when their clocks are synchronized externally to that frame. This entails a predicted aberration of $\arctan(V/c)$, which agrees with the aberration predicted by the LT using the relativistic relative velocity $2v/(1+(v/c)^2)$.\\[4pt] [1] F.R. Tangherlini, ``The Velocity of Light in Uniformly Moving Frames,'' Ph.D. Thesis, Stanford (1958). Publ. in the Abraham Zelmanov Jour.2,44(2009), includes 2009 preface. See http://Zelmanov.ptep-online.com/papers/zj-2009 [Preview Abstract] |
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D1.00034: GENERAL PHYSICS |
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D1.00035: Schools should not be run as businesses Robert Jones Schools, prisons, hospitals, governments and the like should not be run as businesses or following business principles. The reason is simple, most businesses fail in 3 to 5 years and 90\% fail in 10 years. Business methodology more often than not leads to failure. Society should instead prefer and follow the methods of science, engineering and democracy. The scientific method is superior to markets. It has been known for 100 years that groups can produce better decisions than individuals. We should not have chairs, and deans and presidents. Rather, decisions should be taken by workers councils. [Preview Abstract] |
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D1.00036: John Mather public policy internship: Perspectives on science policy as an intern at Scientists and Engineers for America (SEA) and Congressman Bill Foster's office Alexander Tuna In the summer of 2010, I participated in the John Mather public policy internship through AIP and SPS. I spent six weeks as an intern at Scientists and Engineers for America (SEA), a nonprofit, nonpartisan organization that encourages technically-trained citizens to become more engaged in US politics and the policy-making process, and six weeks as an intern for Congressman Bill Foster (D-Il 14) in the House of Representatives. These internships offered two distinct perspectives on how American science policy is crafted and showed me many ways in which scientists can be engaged in the political process. [Preview Abstract] |
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D1.00037: A Time Traveler's History of Physics Robert Close The history of science is often presented as a logical progression of better and better theories to explain increasingly accurate data. However, the reality is that misconceptions can persist long after better explanations are proposed or contrary evidence is available. Many advances in science have been subject to Planck's principle that new scientific truths do not triumph by convincing opponents, but rather because opponents eventually die off. Nobel Laureate Paul Lauterbur recently commented that one could write the entire history of science in the last 50 years in terms of rejected papers. Is it possible to identify misconceptions in the present without waiting for historical judgment? One way to test the robustness of our ideas is to imagine how they would change if historical events had occurred in a different order. For example, if de Broglie's hypothesis of the wave nature of matter had preceded the Michelson-Morley experiment, then aether-drift experiments might have been regarded as tests of the wave nature of matter rather than as tests for the existence of an aether. We incorporate recent work and attempt to construct a logical rather than temporal history of physics. This procedure suggests that many common beliefs about modern physics are subject to reinterpretation. [Preview Abstract] |
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D1.00038: Biopolymers for Medical Applications: Polyglycerol Sebacate (PGS) doped Hydroxyapatite (HA) Maria Teruel, Narayanan Kuthirummal, Nicole Levi In the investigation to engineer the ideal scaffolding device for cleft palate repair, polyglycerol sebacate (PGS) doped with hydroxyapatite (HA) were chosen for their elastomeric and biodegradable properties, as well as their cost- effective synthesis. Hydroxyapatite was integrated into the PGS to form a composite with high porosity and improved mechanical properties yielding a good substrate for cell attachment during the repair process. FT-IR scans were performed to characterize the composite polymer. Differential Scanning Calorimetry (DSC) was utilized to identify an acceptable glass transition temperature (T$_{g}$), between -18 and -21 $^{\circ}$C. At this T$_{g}$, it was determined that the material was sufficiently polymerized to a point where it was durable yet pliable enough to use for cleft palate devices. In the synthesis of PGS 3\% and 5\% HA, a T$_{g}$ of -20.10 $^{\circ}$C and -21.72 $^{\circ}$C, respectively, was achieved and further analytical tests were then performed on the polymers. Methods of analysis included X- Ray Diffraction and Tensile Strength Testing. [Preview Abstract] |
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D1.00039: First Principles Study of Optical Losses in Transition Metals and Alloys A.V. Gavrilenko, C. Gonder, D. Baker, C.S. McKinney, V.I. Gavrilenko Detailed understanding of the physics of optical losses in transition metals is a hot area of modern fundamental science with variety of applications in nano-physics, nano-photonics and nano-plasmonics. The first principles density functional theory is applied to study effects of molecular adsorption on silver (111) oriented nano-films and the alloying effects of Ag$_{1-x}$Cd$_{x}$, and Ag$_{1-x}$In$_{x }$based nanostructures on their optical losses. Optical functions are calculated within the Random Phase Approximation approach. Optical absorption spectra corresponding to the plasmon and band-to-band transitions of alloys show opposite trends in spectral shifts caused by a variation of the content, $x$. With increase of $x$, the electronic energies of band-to-band transitions associated with optical excitations of $d-$electrons indicate well pronounced red shifts. The predicted variations of optical absorption spectra of transition metals alloys agree with experimental data measured on Ag-In and Ag-Cd alloys. [Preview Abstract] |
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D1.00040: Characterization of the Resistive Micromegas Muon Detectors Alexandra Moskaleva The MICRO-MEsh-GAseous Structure (Micromegas) is a particle detector that is a candidate for the ATLAS muon system upgrade. It is a gaseous particle detector that makes use of printed circuit boards for micron-sized readout strips. This creates the potential for high spatial resolution, high rate capability, large sensitive area, operational stability, and radiation hardness. While the MicroMegas detector is being researched in many laboratories, the CERN MicroMegas team has developed a novel resistive design that alleviates many problems associated with the detector such as high spark rate. Several resistive MicroMegas designs were tested to determine their gain and transparency. With the resistive chambers, we observed high gains and transparency, with a minimal spark rate. [Preview Abstract] |
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D1.00041: Neutron Activation Analysis, A Titanium Material Study Charles Dresser In order to obtain faster and more accurate measurements of radioactive contaminates within a sample of titanium we expose it to a neutron flux. This flux will activate the stable and quasi stable (those with extremely long half lives) isotopes into resultant daughter cells that are unstable which will result in shorter half lives on the order of minutes to days. We measured the resulting decays in the Germanium Crystal Detector and obtained a complex gamma spectrum. A mathematical model was used to recreate the production of the measured isotopes in the neutron flux and the resultant decays. Using this model we calculated the mass percent of the contaminate isotopes inside our titanium sample. Our mathematical model accounted for two types of neutron activation, fast or thermal activation, since this would determine which contaminate was the source of our signals. By looking at the percent abundances, neutron absorption cross-sections and the resulting mass percents of each contaminate we are able to determine the exact source of our measured signals. Additionally we implemented a unique ratio method to cross check the mathematical model. Our results have verified that for fast neutron activation and thermal neutron activation the method is accurate. [Preview Abstract] |
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