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 K8: General Physics II |
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Sponsoring Units: 10 21 2017 Chair: Bob Glosser, University of Texas at Dallas Room: JSOM 1.212 |
Saturday, October 21, 2017 10:30AM - 10:42AM |
K8.00001: Introducing the Light Guitar Russell Stoneback The traditional acoustic guitar uses the resonance of strings and instrument body to produce pleasing sounds. We present a variant upon this technique to create a new class of musical instruments, one that uses the resonance of electromagnetic fields (20 MHz- 20 GHz), rather than sound waves, to produce music. From a functional perspective each system in an acoustic musical instrument is replaced with an electromagnetic equivalent. Wooden instruments are replaced with conductive materials, resonant motions of acoustic instrument bodies are replaced with resonant surface currents, and resonances of instrument strings are replaced with the resonance of voltage and current along a coaxial cable. Waves produced by these new musical instruments are not directly visible or audible, but they are measurable, enabling the recording of waveforms and playback of these signals as music. An overview of these new musical instruments will be presented followed by a musical performance. [Preview Abstract] |
Saturday, October 21, 2017 10:42AM - 10:54AM |
K8.00002: Investigating the Applications of Chaotic Oscillators Paul Boulet Many distinct chaotic circuits were developed experimentally to create new, advanced, high-order chaotic systems. Inductor-capacitor (LC) transmission lines working in conjunction with a limiting factor (often a diode) were used to create higher-order differential waveforms in circuits. By lengthening the transmission lines, an easy and accessible way for creating higher-order systems was implemented. Chaos in these systems was observed through the use of analog oscilloscopes set to display the voltage waveform versus its derivative and also through digital oscilloscopes graphing the waveform. Most notably a generalized R\"{o}ssler system was expanded from a sixth-order chaotic system to a never before achieved twelfth-order system. In addition, a second-order solvable exact shift chaotic oscillator was experimentally developed and was nearly progressed to a third order system. This research may be beneficial in creating higher-order chaotic systems as well as serving as the basis for the development of communication systems, reservoir computers, random number generators, and more advanced and efficient radars. We report on the techniques implemented to achieve these higher order chaotic systems. [Preview Abstract] |
Saturday, October 21, 2017 10:54AM - 11:06AM |
K8.00003: Promoting Better Conclusions in Introductory Physics Laboratories Douglas Young Students writing lab reports for introductory physics labs often have difficulty drawing valid conclusions based on their experimental data. The terms accuracy and precision are also typically used incorrectly (i.e. interchangeably) by student in their conclusions. This presentation will describe various methods employed to improve the conclusions students draw from their experimental data. Particular attention will be focused on methods for helping students correctly use the terms precision and accuracy in conclusion statements. Attention will also be given to methods used to help students understand the role of experimental uncertainty in drawing conclusions from their data. [Preview Abstract] |
Saturday, October 21, 2017 11:06AM - 11:18AM |
K8.00004: Quantum corrections to the conductivity of epitaxial grown $SrTiO_{3} $ film on Si Dean Koehne, Ryan Cottier, Daniel Currie, John Miracle, Craig Swartz, Nikoleta Theodoropoulou We use low temperature magnetotransport measurements to study the electronic properties of strained, oxygen deficient $SrTiO_{3} $ (STO) thin films $\left( {d=8-20nm} \right)$ grown on semi-insulating p-Si(001) by Oxide Molecular Beam Epitaxy. The resistance is measured using the Van der Pauw technique and shows insulating behaviors. The resistance increases logarithmically from 50 K to 10 K and when a magnetic field is applied perpendicular to the plane the magnetoresistance (MR) is negative. Below 10 K, we observe Mott's Variable Range Hopping for $\left( {d<15nm} \right)$ and a nonmonotonic MR. The results are analyzed using the conventional theories of weak localization (quantum interference of backscattered electrons) and electron-electron interaction corrections to the conductivity in two dimensions providing evidence for quantum confinement. To more precisely measure the transport, we fabricated Hall-bar structures using photolithography and measured the carrier concentration along with the mobility for both configurations. We discuss the effect of strain due to the lattice mismatch between STO and Si (1.7{\%} compressive in-plane strain), oxygen vacancies and disorder on the electronic properties of this 2d system. [Preview Abstract] |
Saturday, October 21, 2017 11:18AM - 11:30AM |
K8.00005: Correlation of strain and quantum corrections to resistance in very thin films of $SrTiO_{3-\delta } $ on Si through X-ray diffraction measurements John Miracle, Dean Koehne, Ryan Cottier, Daniel Currie, Nikoleta Theodoropoulou Our group has shown that a 2-d electron gas forms in strained thin films of oxygen deficient $SrTiO_{3-\delta } $(STO) grown epitaxially on Si(001). Low temperature magnetotransport measurements show quantum corrections to the Drude conductivity due to both quantum interference and electron-electron interaction (EEI) effects, and insulating behavior with Mott-Variable Range Hopping. The EEI are observed only for low carrier concentrations of $4-9\ast 10^{-12}cm^{-2}$, and for thicknesses less than 15 nm. The coherent growth of STO on Si produces a compressive in-plane strain of 1.7{\%} and a tetragonal distortion. A Mott insulating phase is predicted for STO for large distortions of the crystal structure with Ti-O-Ti angles of $165^{\circ }$ compared to $180^{\circ }$ in the cubic phase and for a high doping level.[1] We use x-ray diffraction to investigate the effect of film strain on EEI and the Mott insulating behavior. Wide angle $\theta -2\theta $ scans along with phi scans of the Si\textbraceleft 202\textbraceright and STO\textbraceleft 202\textbraceright family of planes show coherent crystal growth with STO(002)\textbar \textbar Si(004) and a $45^{\circ }$ in-plane rotation of STO on Si. Rocking curve measurements of STO(002) and the STO\textbraceleft 202\textbraceright verify the tetragonal distortion $\left( {a=b\ne c;\alpha =\beta =\gamma =90^{\circ }} \right)$. We use X-ray reflectivity to measure the thickness of the films, the interface roughness, and composition. [Preview Abstract] |
Saturday, October 21, 2017 11:30AM - 11:42AM |
K8.00006: Negative Drag Coefficient in Electrostatic Pendulum Jose Hernandez, Karl Stephan This paper focuses on the force produced by corona, the electrohydrodynamic (EHD) effect (``ion wind''). In recent years, the EHD effect has been investigated for purposes of aerodynamic drag reduction. We present a simple experiment involving an electrostatic pendulum that demonstrates ``negative drag''. When a thin suspension wire of a ball-bearing pendulum is raised to a high enough DC potential to produce corona, positive feedback is established between the ion wind produced by the corona and the direction of air currents around the wire. This positive feedback produces an effective negative drag that adds mechanical energy to the system and causes the pendulum amplitude to increase approximately exponentially over a period as long as four minutes. In this paper we quantify the net negative drag on the system and propose a qualitative theory as to why negative drag is produced. [Preview Abstract] |
Saturday, October 21, 2017 11:42AM - 11:54AM |
K8.00007: Kepler K2 Observations and Modelling of Algol-type binary KIC201325017 John Jones, Richard Olenick, Arthur Sweeney We present results from long cadence \textit{Kepler} K2 observations covering 64 days of the new Algol-type variable KIC 201325107 also known as LINEAR 2882780. Using Peranso for time series analysis, we detect an orbital period of 0.07441 d and time varying maxima. We create a synthetic model of system using PHOEBE and find a mass ratio $q \quad =$ 0.3493, an orbital inclination $\theta \quad =$ 83.29$^{\mathrm{\thinspace o}}$, and temperatures of $T_{1} = $6204 K and T$_{\mathrm{2}} \quad =$ 3816 K for the primary and secondary stars, respectively.~ In addition, we find evidence for streaming of matter from the secondary to the primary. [Preview Abstract] |
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