Bulletin of the American Physical Society
83rd Annual Meeting of the APS Southeastern Section
Volume 61, Number 19
Thursday–Saturday, November 10–12, 2016; Charlottesville, Virginia
Session K1: Poster Session |
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Chair: Romulus Godang, University of South Alabama Room: Salon B |
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K1.00001: Fermi-LAT daily monitoring observations of the microquasar Cygnus X-1 Stephen Hood, Austin Waldron, Joshua O'Neill, Arash Bodaghee Detection of gamma-ray emission from microquasars is important for understanding particle acceleration in the jet, and for constraining leptonic/hadronic emission models. We present a continuation of a 1-d likelihood analysis on gamma-ray observations by \emph{Fermi}-LAT (0.1--10 GeV) of the accreting black hole candidate Cygnus X-1. Combining this gamma-ray data with available X-ray monitoring data from \emph{Swift} and \emph{MAXI} allowed us to reveal four days (in a two-year period) on which Cyg X-1 displayed low-significance (3--4$\sigma$) excesses, three of which were contemporaneous with apparent transitions in the X-rays. [Preview Abstract] |
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K1.00002: Illustris-Simulated Major Merger Galaxy Pairs at z$=$0 Alice Jacques, Spencer Shortt, Donovan Domingue The Illustris project is a publicly accessible set of large-scale cosmological simulations. In this work we focus on identifying major-merger galaxy pairs (mass ratio \textless 2.5) within the simulation; with the goal of comparing them to observations of SDSS-2MASS selected galaxy pairs. We apply position, mass, and relative velocity criteria to restrict visually identified galaxy sets presented in the Illustris Galaxy Observatory web-based search tool. Application of the criteria creates a sample of probable physical pairs at various stages of pre-merger galaxy interaction. The ultimate objective is to analyze the history of the simulated major-merger galaxies including star formation and merger rates with emphasis on morphological type dependencies. [Preview Abstract] |
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K1.00003: Effects of the passing of a caustic ring through the solar neighborhood Sankha Subhra Chakrabarty, Pierre Sikivie The caustic ring model is a proposal for the full phasespace distribution of dark matter particles in the halos of isolated disk galaxies such as our own Milky Way galaxy. Self-similar time evolution of the dark matter halo implies that the caustic rings lie in the galactic disk and slowly increase their radii, expanding on cosmological time scales. As the caustic rings pass through a particular location in the galactic disk, they disturb the orbits of the stars there. If the galactic disk is initially in a relaxed state, similar to thermal equilibrium, the average values of radial and vertical velocities for sufficiently large number of stars at a given position, would vanish. Recently, position-dependent bulk velocities of the stars have been observed in the extended solar neighborhood. We investigate if a passing caustic ring may cause such perturbations in the radial and vertical bulk velocities. [Preview Abstract] |
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K1.00004: Comparing the spatial distributions of HMXBs and star-forming regions in the Small Magellanic Cloud Ryan Agnew, Brenton Jackson, Arash Bodaghee, Zach Jordan, Eric Frechette, V. Antoniou, A. Zezas, J.A. Tomsick Initial results are presented comparing the spatial distribution of high- mass X-ray binaries (HMXBs) and massive stellar nurseries (OB associations) in the Small Magellanic Cloud (SMC). The analysis involves constructing the two-point cross-correlation function (Landy-Szalay) between pairs of 72 HMXBs and 234 OB associations with the latter being randomly reshuffled following a homogenous distribution, a Gaussian distribution, and exponential disk distribution, and a distribution that mimics the star-formation history of the SMC. We find a significant correlation between the observed HMXB and OB catalogs compared with a random catalog in which the OB associations are distributed homogeneously across the SMC field. On average, within a 0.5 kpc of a given HMXB, there are 4 OB associations from the observed catalog for every one from the randomized catalog. There is no significant difference when comparing the HMXBs with the observed catalog versus the random catalog in which the OB distribution traces the star-formation history. This suggests that HMXBs in the SMC have had less time to migrate away from their birthplaces (or, alternatively, that they have a lower average velocity) than HMXBs in the Milky Way. [Preview Abstract] |
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K1.00005: Characterization of an Extremophile Based Chlorophyll Raman Threshold Signal in Martian Regolith Simulant as a Potential Astrobiological Agent Keith Andrew, Kristopher Andrew, Melinda Thomas, Quentin Linebery, Alicia Pesterfield, Phillip Womble As NASA prepares for missions to Mars there is a need to determine the viability of the Martian regolith at proposed landing sites. Data from the Mars Curiosity Rover mission has produced direct sampling of the Martian surface allowing for the production of a bulk regolith simulant: JSC Mars-1. This material can be combined with other trace elements in a laboratory setting to develop threshold tests for potential interesting and novel measurements, including molecules that can be preserved on Mars in a shielded environment underground. In particular the Martian climate represents a potentially survivable environment for several Archaea based extremophiles that have been identified on Earth. A number of these species include cyanobacteria with chloroplasts that are found in eukaryotes and prokaryotes that carry versions of chlorophyll that could be left as a trace material. Following B\"{o}ttger we perform coupled Raman and NFOM measurements on samples with various concentrations of chlorophyll embedded in a five MPa compressed casing of JSC Mars-1 Martian regolith simulant to determine guidelines for the minimum threshold for detection. We compare lines identified in the spectra of the chlorophyll samples and find a threshold sigmoid near 181 ppb level of concentration. [Preview Abstract] |
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K1.00006: Linear Spectral Shift Determination of Hydrated Metallic Sulfates in Martian Regolith Simulant JSC Mars-1 Keith Andrew, Kristopher Andrew, Melinda Thomas, Alicia Pesterfield, Quentin Lineberry, Jon Paschal Recent data from the Curiosity and Opportunity Martian rovers coupled to the Mars THEMIS orbiter measurements have indicated that sulfur compounds play an important role in Martian meteorology. The unique identification and concentration of metallic sulfates in the Martian Regolith is critical to understanding the atmospheric and ground water dynamics on Mars. Metallic sulfates can form several hydrated states that can hold water in the Martian equatorial regions, can provide shielding from cosmic rays and solar radiation, can give rise to the development of an underground permafrost layer and can help form polar region ice. Following Sharma we combine Raman spectra of several hydrated sulfates that are imbedded in JSC-1 Martian regolith simulant at different concentrations and quantify the shift in peak values as a function of hydration. Different hydrated states have perturbed unit cell structures that cause the sulfate groups to oscillate with different symmetric and antisymmetric phonon mediated frequencies. Here we derive an explicit expression for the symmetric mode Raman iron based sulfate shift as a function of hydration and find the threshold detection level in the JSC-1 Martian Regolith. [Preview Abstract] |
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K1.00007: Analysis of Mass and Radius Sensitivity of a Crystalline Quark Star to a Strong Repulsive Equation of State. Keith Andrew, Rebecca Brown, Kristopher Andrew, Benjamin Thornberry, Seth Harper, Eric Steinfelds, Thad Roberts Recent data measuring the Quark-Gluon Plasma state from the Relativistic Heavy Ion Collider experiments have resulted in a more accurate determination of the QCD phase diagram. The high temperature results indicate that there exists a phase transition that gives rise to the deconfinement of quarks with the formation of the quark gluon plasma. Such a phase transition may play an important role in stable compact star core formation beyond the neutron star state but prior to reaching any black hole state. Here we numerically solve the Tolman-Openheimer-Volkov equations for a static spherically symmetric mass distribution with an effective crystalline quark cluster Equation of State with a phonon term following the method of Lai. The static multi-quark interaction potential is established for a specific crystalline lattice structure which gives rise to stable end states with higher masses and smaller radii than typical neutron stars. We determine mass, pressure, density and temperature radial profiles for these configurations. We then compare these states to the causality and general relativity bounds on stiff matter and determine the sensitivity to the exponent of the two body repulsive potential interaction for a stable crystalline quark star state. [Preview Abstract] |
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K1.00008: A QCD Model of the Chemical Potential Kaon Boundary Formation for a Compact Quark Star. Keith Andrew, Kristopher Andrew, Rebecca Brown, Benjamin Thornberry, Seth Harper, Eric Steinfelds, Thad Roberts A signature of the QCD phase transition from bound hadronic states to the quark gluon plasma is a change in sign of the chemical potential for the strange quark. The combined data from ALICE, RHIC, and CBM have been used to identify the energy regime where the sign change takes place. Following the work of Baym we use a QCD motivated equation of state to model the change in chemical potential associated with the three lightest quarks and fit the resulting temperature dependent chemical potentials to the accelerator data. These functions are then coupled to a quark star model to determine the interior pressure and temperature as functions of the compact core radius. When the interior pressure is high enough the strange quark chemical potential will shift below the up and down quark chemical potentials making strange quark production favorable. This results in the formation of a boundary layer in the star initially separating free up, down and strange quarks from up and down confined quarks. The strange quarks at the boundary will undergo weak interactions with a strong branching ratio for Kaon formation and thereby result in copious neutrino production. Here we develop a model to find the radial location of the Kaon boundary layer in a quark star. [Preview Abstract] |
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K1.00009: Medium's Properties Influence the Redshifting / Blushifting and Lensing Florentin Smarandache The longer is the medium corridor a wave passes through, the larger is the probability of the medium redshifting/blushifting and lensing of that wave. The wave may interfere or superposition with other medium's waves. Medium's Properties that play an important role: dynamicity of the medium; medium and wave interactivity; medium's electrostatic/magnetostatic/gravitational potentials at each point in the medium that the interest wave passes through; medium's degree of refractivity and degree of diffractivity; medium's selectivity (ability to discriminate against the wave of interest that has a different frequency); medium's energy density; medium's magnetic flux density and direction (permeability/reluctivity); medium's transmissivity (ability to transmit radiation); medium's diffusivity; medium's vibrations and oscillations; medium's sensitivity to waves and particles; the degree by which medium's solids and fluids mix with one another (diffusion); medium's distorticity; etc. The redshifting/blushifting and lensing are much more complex than the simple Doppler's apparent Effect or only the Gravitational Lensing (therefore, this questions Hubble's Law). Not all of these properties would have a much impact but some of them amplify the redshifts/blushifts and light bending. [Preview Abstract] |
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K1.00010: Georgia College Raspberry Busch Taylor O. Huffington, James D. Vogt, Jerome McKissic, Sharon L. Careccia, Ralph H France III The Georgia College Raspberry Busch (GCRB) is an inexpensive solution to our computational Astronomical needs. The Raspberry Pi 2B is a 35 dollar computer not much larger than a credit card. Each unit Pi has a 1 GHz quad core ARM CPU, 1GB RAM and a 32GB SD flash memory of wich 4.5GB is occupied by the operating system. Currently the GCRB is a cluster of 8 Raspberry Pis.To expand the system, simply flash a slave image onto a fresh SD card and assign a new IP address. We plan to present benchmarks.The GCRB will be used to process astronomical data. [Preview Abstract] |
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K1.00011: A Polarimetric Approach for Constraining the Dynamic Foreground Spectrum for the Cosmological Global 21-cm Measurement Bang Nhan, Richard Bradley, Jack Burns The cosmological global (sky-averaged) 21-cm signal is a powerful probe for the intergalactic medium (IGM) evolution in high-redshift Universe ($\sim 380,000 - 400$ million years after the Big Bang). The biggest observational challenge is to remove the much brighter foreground to reveal the 21-cm background spectrum. Conventional global 21-cm experiments rely on the spectral smoothness of the foreground synchrotron emission to separate it from the distinct 21-cm spectral structure in a total-power spectrum. However, frequency-dependent instrumental and observational effects are known to corrupt such smoothness and complicate the foreground subtraction process. We introduce a polarimetric approach to measure polarization induced by the projection of the anisotropic foreground onto a stationary dual-polarized radio antenna. Due to Earth rotation, by pointing the antenna at a celestial pole, the induced polarization is modulated as function of time by twice the sky rotation rate. By Fourier decomposing this dynamic signature at each observed frequency, we obtain a foreground spectrum independent from the isotropic background signal. This foreground spectrum helps to improve accuracy of constraining the global 21-cm signal and the associated astrophysical quantities. [Preview Abstract] |
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K1.00012: Cores in Clumps - An ALMA view of a forming massive cluster Yu Cheng, Jonathan Tan, Shuo Kong, Mengyao Liu The formation of stars in clusters is a central problem in the study of star formation and several fundamental questions are still debated, including the timescale and efficiency. The formation and early evolution of clusters involves the interplay of fragmentation from turbulent motions and gravity, dynamical motions of young stars, and the feedback from the young stars. Observationally, spatial, kinematic and mass distribution properties of cores in a protocluster can help constrain different theratical models. We map the massive protocluster G286.21$+$0.17 with ALMA in the 1.3 mm band to study its gas and dust structures. And here we present a preliminary analysis of the data, including a study of the core mass function within the cluster. [Preview Abstract] |
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K1.00013: Resolving the Mid-Infrared Population in Massive Protoclusters Allison Towner, Crystal Brogan, Todd Hunter, Claudia Cyganowski, Stella Offner, Remy Indebetouw Simultaneous outflows from multiple protostars likely play an important and perhaps crucial role in forming a cluster containing massive stars (a ``protocluster''). We have identified a sample of 20 typical Galactic protoclusters existing in a specific early evolutionary state in which outflows dominate their appearance in the IRAC bands. We have recently completed surveys of the circumprotostellar environment of these protoclusters at 1.3~cm and 1.3~mm. We recently observed 9 of these protoclusters with the SOFIA FORCAST instrument at 19.7 and 37.1 $\mu$m. Targets were selected based on evidence for 1.3~mm multiplicity in the 1.3~mm data and inadequate 24 $\mu$m observations. In this poster, we present first results from these new data. The high angular resolution and sensitivity of the SOFIA data offer a substantial improvement over existing data for these objects and is well-matched to our longer wavelength images. With these observations, in conjunction with our existing longer wavelength data, we plan to construct SEDs for the protoclusters. These SEDs will allow us to constrain the mass and temperature of the intermediate- to high-mass protostars within the observed 1.3~mm dust cores, as well as to constrain ancillary information such as extinction, accretion rate, etc. [Preview Abstract] |
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K1.00014: WISE Photometry of Major Merger Galaxy Pairs Joseph Ronca, Alice Jacques, Donovan Domingue A full understanding of the Spectral Energy Distribution(SED) of galaxies benefits from the inclusion of near- infrared(IR) to mid-IR data such as Wide Field Infrared Survey Explorer(WISE) data. Exploring the SED of galaxy pairs and corresponding control samples provides insight in to the evolution of star formation and dust composition in galaxy interactions. After investigating the validity of multiple WISE photometry methodologies, use of the unWISE photometry catalog was found to best characterize the objects of the study. Determination of the best WISE photometry allows us to conduct a preliminary search for Active Galactic Nuclei(AGN). We conclude that there is an insignificant population of WISE determined AGN in our sample of major merger (mass ratio less than 2.5) galaxy pair candidates. [Preview Abstract] |
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K1.00015: On the Modelling and Measurement of Dwarf Galaxy Tucana III Brandon Buncher Measurements of the mass distribution of the universe using a variety of independent techniques indicate that there exists a significant portion of mass that does not interact via light. There is mounting evidence that this missing mass, or ``dark matter,'' exists in high concentrations in ultra-faint dwarf galaxies. These galaxies, however, have remained hard to find due to difficulties with detecting them at high resolution. The Dark Energy Survey (DES) has revolutionized the study of dwarf galaxies by providing high resolution, deep-field images of these systems. In this project, we perform measurements on Tucana III, a tidally disrupted dwarf galaxy in the Tucana constellation orbiting the Milky Way, in order to improve our understanding of the dark matter distribution of the Milky Way. We isolated the galaxy using an isochrone selection algorithm, then performed measurements of the position angle, tail length, tail width, and tail offset. The results of this project will aid in future dark matter observational studies, as well as shed light on the behavior of dwarf galaxies and other Milky Way satellites. [Preview Abstract] |
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K1.00016: Group Halo Mass and Galactic Disk Evolution in the RESOLVE Survey Kate Kushner, Sheila Kannappan, Kathleen Eckert, David Stark, Jonathan Bennett Groups and clusters of galaxies are surrounded by dark matter halos whose masses may be related to disk formation in member galaxies. Using galaxies included in the RESOLVE survey, we examine the relationships between group halo mass and characteristics of the galaxies that serve as proxies for disk formation. Among these is the (g-r) color gradient, a measure of the blue centeredness of galaxies. The (g-r) color gradient indicates that a galaxy is bluer (redder) -centered when its center emits more blue (red) light than its edges. We find that group halo mass and the (g-r) color gradient display a correlation such that galaxies in higher halo masses are redder-centered than those found in lower halo masses. Since the majority of RESOLVE galaxies are more red-centered than blue-centered, the majority of these galaxies have a higher proportion of blue stars in their outer regions, which, in conjunction with blue absolute disk color, may suggest the presence of star-forming disks. Only at small halo masses does a minority of bluer-centered galaxies emerge, perhaps as a result of interactions between galaxies or fresh gas accretion. We find that the gas mass to stellar mass ratio displays a negative correlation with halo mass, indicating that galaxies found in groups with smaller halo masses (\textasciitilde 10\textasciicircum 11.5 solar masses) are more strongly gas-dominated and are likely to form disks. We discuss the possible implications of our (g-r) color gradient and gas mass to stellar mass ratio results for disk formation. [Preview Abstract] |
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K1.00017: Interstellar extinction in the direction of six open clusters Gregory Topasna Multi-wavelength polarization measurements of six open clusters is presented. For select stars in each cluster, the wavelength dependence of polarization due to selective extinction is determined. Using the wavelength of maximum polarization, the ratio of total-to-selective extinction is determined and an average value for each cluster is reported. [Preview Abstract] |
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K1.00018: Determining Vsin(i) of Young Planet-hosting Stars Jennifer Medina, Andrew Mann Constraining the spin-orbit alignment of close-in planets in young systems can provide insight on their migratory history. We can combine Vsin(i) with measurements of the stellar rotation period and radius to determine the star's orbital inclination, which we can compare to that of the planet as determined from the transit. Vsin(i) is determined from the rotational broadening on the star's spectral lines, so it is ideal to work with young, fast-rotating stars where broadening is more easily measured. We measure Vsin(i) of seven planet-hosting stars within the Praesepe star cluster by using high-resolution spectra from the Immersion Grating INfrared Spectrometer (IGRINS) in the K and H band filters. We develop a program to fit the model onto each order of the spectra using a set of optimized parameters which takes into account complicating factors such as instrumental broadening, stellar motion, and atmospheric turbulence. For our final result, we find that all planet hosts are spin-orbit aligned within measurement errors. [Preview Abstract] |
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K1.00019: Neutrosophic Magnetic Field Florentin Smarandache Let $\Psi $ be a magnetic pole or a conductor throughout which a current flows. The field of force surrounding $\Psi $, where does exist a magnetic flux, is actually a \textit{Neutrosophic Magnetic Field}, because it is formed by three main zones, as in neutrosophy \textbraceleft \textless $\Psi $\textgreater , \textless neut$\Psi $\textgreater , and \textless anti$\Psi $\textgreater \textbraceright : - magnetic field inner-zone, where the magnetic force generated by $\Psi $ acts completely \textbraceleft zone \textless $\Psi $\textgreater \textbraceright ; - magnetic field neutro-zone \textbraceleft neutral or indeterminate zone \textless neut$\Psi $\textgreater \textbraceright , which is a buffer zone between two opposites, where the magnetic force generated by $\Psi $ is vague, unclear; - and magnetic field outer-zone \textbraceleft opposite zone \textless anti$\Psi $\textgreater \textbraceright , where the magnetic force generated by $\Psi $ does not act at all. In general, it is not a steady frontier between the magnetic field inner zone, and magnetic field outer zone, but a buffer zone between these opposites. As a consequences, if $\Psi $ is a celestial object - for example the Earth, or any other planet, also the Sun, or any other star -, their gravitational field frontiers are not steady, but neutral / indeterminate magnetic field buffers. [Preview Abstract] |
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K1.00020: Preliminary Accelerated Aging Studies for the Mu2e Cosmic Ray Veto System Tyler Lam The Mu2e experiment will conduct a search for charged lepton flavor violation through observation of a neutrino-less muon to electron conversion. In order to prevent interference from cosmic ray muons, a cosmic ray veto shield (CRV) consisting of counters made from scintillating plastic will be read out by wavelength shifting fibers. To ensure cosmic rays are not mistakenly detected as false positive muon to electron conversions, the CRV must have a detection efficiency of 0.9999. Due to the long-term nature of this experiment, veto counters must continue to function efficiently for up to 10 years. Accelerated aging studies will measure the effects of aging on the light yield of scintillator and transmission of light through optical fibers. An oven will heat samples to simulate 10 years of aging in only 1 year, and studies on these samples will be conducted to measure the effect of aging. Tests include measuring the attenuation of light through the aged optical fiber using an LED flasher with a photodiode or spectrometer and measuring the response of aged counters to radioactive sources and cosmic rays. [Preview Abstract] |
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K1.00021: Measuring the top-Higgs coupling at CMS Evan Wolfe, Chris Neu With the discovery of the scalar boson in 2012~and measurements corresponding thus far to the standard model prediction of the Higgs, the future of experimental particle physics has become much more broad with respect to the search for new physics.~ Observations of the interaction between the Higgs boson and top quark are also needed to clearly identify the new boson's properties and allow its full classification in the standard model.~Theory predicts the Higgs to couple strongest to the top quark, allowing an excellent probe into the current understanding of the standard model by measuring ttH production at the CMS detector. Measuring ttH production is the only direct method for measuring the top-Higgs coupling which could provide both a reach into new physics and constrain extensions to the standard model such as Little Higgs, composite Higgs and Extra Dimensions. The direct probe of the top-Higgs coupling through ttH will be able to shed light on extensions to the SM by comparisons to theoretical cross-sections and the method of electroweak symmetry breaking with the most massive fermion found to date. In this talk I'll present results from Runs I and II and our current outlook as the LHC now moves into higher luminosities. [Preview Abstract] |
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K1.00022: Milliseconds~Difference between Recorded Arrival Signals by Detectors in LIGO as the Observable Factor for Time Fluxes which Arise by Momentum Hassan Gholibeigian, Abdolazim Amirshahkarami, Kazem Gholibeigian Different locations in two merged massive black holes including different large scales convection system\textbf{s }which produce different momentum and energy before, during, and after the event. Th\textbf{is} black hole, as a large scale convection system, produces gravitational waves which radiate away. On the other hand, the nature of time is wavy-like motion of the matter and magnitude of the time for an atom is momentum of its involved fundamental particles. So, gravitational waves which travel from black hole to us including different fluxes of time. As an observable factor, we can look at the 7 milliseconds difference of recorded at the time of arrival of the signals on September 14, 2015 by detector in Livingston before detector in Hanford. This difference of recorded time in LIGO cannot be due to warped space-time, because 3002 kilometers distance between two detectors with respect to the 1.3 billion light years (distance of black hole to detectors) is like zero! So, this difference of time's fluxes can be due to gravitational waves of different momentum which produced in different locations of the two merged black holes. [Preview Abstract] |
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K1.00023: Using Derivatives of Time's Flux with Respect to Space-time in Generalized Planck-Einstein Equation and de Broglie Wavelength Relations Hassan Gholibeigian, Abdolazim Amirshahkarami, Kazem Gholibeigian In our vision, the nature of time is wavy-like motion of the matter and nature of space is jerky-like motion of the matter. These two natures can be matched on wave-particle duality of elementary particles [Gholibeigian, et.al. APS April Meeting 2016, abstract {\#}1.032]. On the other hand, it seems that the variation of time's flux (time's dimensions) arises from different geometries of extra dimensions of string which are in face-front of the string's motion. So, we propose to use derivatives of time's flux, $R=f(mv,\sigma ,\tau )$, with respect to the space-time for modification of the Generalized Planck-Einstein equation and de Broglie wavelength relations as follows: n.t_{p} \frac{\partial R}{\partial \tau }+P^{\mu }=n.t_{p} \frac{\partial R}{\partial \sigma }+\frac{h}{2\pi }K^{\mu } In which $\sigma \& \tau $ are coordinates on the string world sheet, respectively space and time along the string, $m$ is string's mass$, \quad v$ is velocity of string's motion$, \quad n$ factor \quad depends on geometry of each extra dimension \quad which is in face-front of the motion, and $t_{p} $ is Planck's time. [Preview Abstract] |
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K1.00024: Polarization effects in $Z \gamma$ resonance searches with boosted jets Abasi Brown, Ayana Arce The ATLAS experiment at the Large Hadron Collider is searching for evidence of the production of particles not predicted by the Standard Model of particle physics. If such a particle were to be discovered, collision data would be used to determine its intrinsic properties, such as its rest mass, charge, and spin. This project investigates hypothetical particles produced in proton collisions that decay to a $Z$ boson and a photon, where the $Z$ boson decays to a quark-antiquark pair, using simulated $pp$ collisions at $\sqrt{s}=$ 13 TeV. By studying the decay angles of the quarks in the rest frame of the $Z$ bosons, what can we learn about the spin of the parent particle? Would assumptions regarding its spin affect our ability to discover it? [Preview Abstract] |
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K1.00025: QIE 11 Testing for the CMS Detector Shaun Hogan During a proton-proton collision in the Compact Muon Solenoid (CMS) at the Large Hadron Collider (LHC), final-state particles pass through different layers of the detector, and data about their characteristics is collected via a complex, multi-level processing system. One such layer in the detector is the hadronic calorimeter (HCAL), which is responsible for detecting hadrons. When hadrons are collected in the HCAL, they pass through scintillation material and emit light, which is then converted to pulses of current by silicon photomultipliers. Once these pulses are produced, they go to Charge Integration and Encoder chips (QIE chips), and are processed into a useable signal. As part of planned upgrades to the CMS detector, a new version of the QIE chips -- version 11 -- is set to be installed. In preparation for these upgrades, we looked at sets of twelve QIE 11 chips arranged onto cards, and performed quality-assurance tests on them to ensure that they are functional and safe to be implemented in the CMS detector. [Preview Abstract] |
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K1.00026: Characteristic Signal of Neutron-Antineutron Oscillation in Argon Nuclei at DUNE. Joshua Barrow, Yuri Kamyshkov, Ben Rybolt Babu et al. have recently proposed a model of post-sphaleron baryogenesis following the electroweak phase transition. Their theory naturally gives rise to a plausible baryon abundance and a $\Delta $B$=$2 six-quark operator which allows for the generation of nbar from n. Using n bound in Ar, DUNE currently plans to include n-nbar events in their nucleon decay searches. Using GENIE, modeling is underway on intranuclear interactions mimicking n-nbar annihilation in Ar nuclei. Eliminating atmospheric $\nu $ background from such events will be a challenge for liquid Ar TPCs at DUNE, so simulation work must be considered for $\nu $ interactions in Ar nuclei, which produce similar signals to n-nbar annihilation. Key to understanding possible experimental signals will be the integration of these two for a proper robust analysis, which will determine the viability of any detection of this process above background levels. [Preview Abstract] |
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K1.00027: Micro Penning Trap for Continuous Magnetic Field Monitoring in High Radiation Environments Javiera Latorre, Georg Bollen, Kerim Gulyuz, Ryan Ringle, Philippe Bado, Mark Dugan With new, high-power, facilities for rare isotope beams, like FRIB at MSU being built, there is a need for new instrumentation for monitoring the magnetic field in beam line magnets that can withstand high levels of radiation. Currently NMR probes, the instrument used extensively to monitor magnetic fields, do not have a sufficiently long lifespan in high-radiation environments. Therefore, a radiation-hard replacement is needed. We propose to use Penning trap mass spectrometry techniques in order to measure magnetic fields with high precision. Our Penning microtrap will be radiation resistant as all of the vital electronics will be at a safe distance and the trap itself will suffer very little degradation as the materials it is constructed from are not subject to radiation damage. Penning trap mass spectrometers can determine the magnetic field through a measurement of the cyclotron frequency of an ion with a known mass and charge. This principle is used on the Low Energy Beam Ion Trap (LEBIT) minitrap at NSCL which is the foundation for the microtrap. We have partnered with Translume, to develop a microtrap in fused-silica glass. A prototype microtrap has been installed in a test station at NSCL, and commissioning has begun. [Preview Abstract] |
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K1.00028: 3D Printing of Plastic Scintillators Emily Vanderwolf, Ralph H France III, Sharon L. Careccia There are many ways to manufacture scintillators, but unfortunately many of these methods involve the costly machining of crystal materials. We plan to reduce the cost by attempting to manufacture plastic scintillators using a 3D printer. The most difficult challenge has been making transparent prints. We have had success with PET, the same plastic used in soda bottles. Upon successful clear plastic prints, we intend to use recycled bottles to manufacture out own fiber. [Preview Abstract] |
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K1.00029: Electrical Characterization of CdZnTe-based Radiation Detectors at Extreme Temperatures. Stephen Babalola, Jonathan Lassiter, Robert Smith, Kristina Williams, Kalen Mumford Cadmium Zinc Telluride has emerged as a material of choice in optoelectronic applications requiring high band-gap and high-Z materials, and has been used in several applications from radio isotopic detection at portal stations for homeland security, imaging for medical research and high-energy radiation detection in astrophysics. For this reason, CZT semiconductor crystal properties have been studied extensively with a focus on correlations of native and induced defects to the radiation detector performance. Due to the wide variety of applications, especially those requiring operations at extreme temperatures such as in Astrophysics, it is important to understand the performance at such extreme temperatures. Previous works by many researchers have shown electrical properties of heat-treated CZT crystals, however, in-situ electrical properties characterization is needed to mimic real-life applications. In this work we studied the electrical properties of CZT detectors while operating at extreme temperatures. Current-voltage measurements were obtained while the detector, placed inside of a furnace, was heated at varying temperatures. The results of this effort are presented. [Preview Abstract] |
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K1.00030: Development of a Prototype Calorimeter for Hall D at JLab Joshua Crafts, Kevin Cosnahan Future forward calorimeter upgrade (FCAL-II) in Hall D at JLab will replace the existing lead glass counters in the central region of the calorimeter with high granularity, high resolution and radiation resistance PWO crystal counters. Two issues are important for this project. The first one is the magnetic shielding on the photo multipliers (PMT) since the FCAL-II will work in the fringe field of a superconducting magnet (at level of \textasciitilde 60 Gauss). The second issue is the high rate for the counters near a high intensity photon beam. As undergraduate students, we worked two months at JLab during summer 2016. We took major responsibility to study the magnetic effect on the Hamamatsu 4125 HA PMT and to develop a passive magnetic shielding with mu-metal. We also involved in developing a small prototype calorimeter for a beam test in the fall 2016. We will present the status and some results of these activities. [Preview Abstract] |
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K1.00031: Compton Effect Chace Covington, Nicholas Tomlinson, R. Seth Smith The Compton Effect experiment was performed with the Leybold Didactic Model 554801 X-Ray Apparatus with a Molybdenum anode. The Compton Effect was a critical experiment in the history of physics, because it provided striking evidence for the existence of photons. In the Compton Effect, high energy x-rays are scattered from free electrons, and the corresponding scattering angles can only be explained by treating the x-rays as photons (particles). In this experiment, the 17.4 keV x-rays are produced with a Molybdenum anode and are scattered from a plexiglass target. The results of this experiment and the performance of the x-ray apparatus will be presented. [Preview Abstract] |
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K1.00032: Broadband laser excitation of van der Waals polymers in a cold atomic gas. Jianing Han Van der Waals interactions are generally studied in physics, chemistry, biology, and other fields of science. Stable van der Waals Rydberg molecular states, all the atoms in the molecule are in excited states, have been studied. In this article, we study the molecular states excited from a broadband laser or few-photon excitations. It is shown that more molecular states are observed. In other words, broadband laser excitation will create more molecular states than a narrow band laser excitation, or the dipole-blockaded case. Dipole-blockade is promising for quantum information and has been studied intensively. Dipole-blockade can be avoided by a broadband laser excitation. In this article, three-body and four-body dipole blockade caused by van der Waals interactions will be investigated. The results can be used to test the feasibility of ultracold atoms as an alternative energy source. [Preview Abstract] |
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K1.00033: Fluorescence of Erbium Dopant in CsCl-Ga-Ge-S glasses for IR applications Jonathan Bunton, Oleh Shpotyuk, Laurent Calvez, Roman Golovchak Over the course of many investigations, CsCl modified Ga-containing germanium sulfide glasses and ceramics have proven to have one of the best host matrixes for rare-earth element doping, creating an ideal material for optical sensing, as active medium for lasers, or in optical amplifiers and broad band sources. This particular study investigates the room- and cryogenic-temperature (via liquid nitrogen) fluorescence of 65GeS$_{\mathrm{2}}$-25Ga$_{\mathrm{2}}$S$_{\mathrm{3}}$-10CsCl glasses doped with Er. The emission spectra were recorded in 1000-1700 nm wavelength range, using excitation wavelengths from 300-950 nm (using Horiba Fluorolog-3 spectrometer). At room temperature, strong emission lines at \textasciitilde 1.55 m corresponding with \textasciitilde 530 nm excitation wavelength were observed in Er-doped samples. At liquid nitrogen temperature, the excitation wavelength for this emission line gradually shifted towards lower values (\textasciitilde 400-450 nm). These observed emission lines agree well with known energy level transitions of Er$^{\mathrm{3+}}$ ions incorporated in the glass matrix. [Preview Abstract] |
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K1.00034: Reduction of four-wave mixing using Raman Absorption in Rubidium Vapor Nikunjkumar Prajapati, Irina Novikova Electromagnetically induced transparency (EIT) is a two-photon resonance, occurring during the interaction of two optical fields -- strong control and weak probe -- with resonant atomic levels in a Lambda configuration.~~A pivotal tool for next generation information technology, it allows for lossless propagation and group velocity manipulation of light. However, in an optically dense atomic vapor, EIT is accompanied by a four-wave mixing (FWM) that results in a generation of a third (Stokes) field and amplification of the probe. This in turn diminishes the fidelity of EIT-based quantum memory. In this presentation we will discuss the possibility to reduce the negative effects of FWM by absorption of the generated Stokes field using additional Raman absorption. We will report on the preliminary results. [Preview Abstract] |
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K1.00035: Tailorable Dispersion in a Ring-Laser Cavity Demetrious Kutzke, Eugeniy Mikhailov, Irina Novikova, Owen Wolfe We present progress toward achieving controllable dispersion in a ring-laser cavity with the goal of improving rotation sensitivity in ring-laser gyroscopes. Preliminary results show that we can tailor the intra-cavity dispersion's slope of our laser based on an N-level pumping scheme of 87Rb. We can tune the pulling factor (PF), i.e. the ratio of the laser frequency shift to the empty cavity frequency shift, of our laser by more than an order of magnitude by varying experimental parameters such as atomic density, pump power, and laser detunings. [Preview Abstract] |
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K1.00036: Enhancement of Second Harmonic Generation by Localized Surface Resonance Plasmons Alexander Allen, Andrew Traverso, Jonathan Bennett, Maiken Mikkelsen We introduce an improved method of manufacturing materials that produce large enhancements of second harmonic generation. This is a step towards achieving nanoscale optical switching for applications in computing and telecommunications. To do this we use a combination of ionically self-assembled monolayers (ISAM) and silver nanocubes atop a gold substrate. Within the ISAM layers, a compound with a high second-order electric susceptibility value is used to generate the second harmonic frequency. The silver nanocubes enhance the pump wavelength by forming localized surface resonance plasmons between themselves and the surface of the substrate. The plasmonic enhancement of the incident wave allows it to maximally generate second harmonic light waves possible from the pump wave. This configuration is tunable to resonate with incident light over a wide range of wavelengths. Our results show definitive production of strong second harmonic waves from our assembly. We will discuss example data comparing our assembly to traditionally used nonlinear crystals such as KDP, and similar previous attempts at second harmonic generation. [Preview Abstract] |
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K1.00037: Kinetics of Photo-Response of Arsenic Sulphide Thin Films Josh Allen, Jonathan Bunton, Maria White, Caity Thomas, Stanislav S, Miroslav Vlcek, Tetyana Ignatova, Andriy Kovalskiy Thin films of chalcogenide glasses are attractive materials for various optical applications due to their transparency in IR region, high refractive index and numerous photoinduced optical effects. In-situ kinetics of photodarkening in thermally deposited and spin coated thin films of different compositions within As(x)S(100-x) system have been studied in dependence on light energy and intensity. It was found that in thermally deposited films the high-energy UV irradiation causes much faster and more pronounced reversible optical changes comparatively to the bangap radiation of the same intensity. Additionally irreversible part is much longer for the bandgap light irradiated thin films too. It was established that decrease of As content results in increase of photoinduced response. At the same time, spin coated films revealed significant reversible photo induced effects when exposed to intense (\textasciitilde 200 mW) UV light and almost complete photostability to the bandgap light, Structure of freshly prepared and irradiated films was studied by Raman microscopy [Preview Abstract] |
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K1.00038: Building a Lock-in Amplifier for an Ionization Experiment Mason Ruby, Stefan Zigo, Brandin Davis, Brett DePaola, Carlos Trallero-Herrero A lock-in amplifier is a device used to recover information from an electric signal with a high signal-to-noise ratio. It achieves this using phase sensitive detection in which a periodic signal is multiplied by a reference signal with the same frequency. The result is then integrated, resulting in a DC signal proportional to the original signal without any influence from the noise. Our research focused on implementing this technique in an ionization experiment utilizing time-of-flight mass spectrometry so that we could dramatically increase the range of our detector. The experiment required that we keep the waveform of the signal intact which is usually impossible with a lock-in amplifier since the output is a DC signal. We developed a method in which the phase of the reference was incrementally changed, causing the output of the lock-in to change also. Taking the derivative of the output reproduced the original waveform. Thus, we were able to show that it is possible to retrieve temporal information from a lock-in amplifier, potentially allowing us to use it for this experiment as well as any other requiring a large detection range. [Preview Abstract] |
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K1.00039: Fluorescence of Pd-doped Ti:CMAS glass and glass-ceramics Laura Nichols, Roman Golovchak Room- and low (liquid nitrogen)-temperature fluorescence is measured for novel Pd-doped Ti-containing calcium magnesium aluminosilicate (Ti:CMAS) glasses and glass-ceramics prepared in air and forming gas atmospheres. A broad fluorescence peak at \textasciitilde 560 nm from F$+$ color centers, observed at 77 K in Pd-free and Pd-doped Ti:CMAS parent glasses under the excitation wavelengths of 300-320 nm, suggests the presence of significant concentration of oxygen defects in the vicinity of titanium ions. These defective titanium octahedra (TiOn, n\textless 6) are assumed to be found in close proximity in the structure of parent glasses. Glass-ceramics made in forming gas do not show any fluorescence at all, while the samples ceramized in air show blue emission at \textasciitilde 490 nm at the liquid nitrogen temperature under the excitation wavelengths of 260-280 nm. This fluorescence is associated with a UV-excited charge-transfer transition from the 2p orbits of the surrounding oxygen ion to the vacant outer 3d orbit of Ti4$+$, followed by the radiative annihilation. [Preview Abstract] |
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K1.00040: Investigations of Low-Cost, High-Precision Optical Measurements Steven Stetzler, E. Craig Dukes We describe an inexpensive platform used to make precise optical measurements of object dimensions using a standard desktop flatbed scanner. Recently, low-cost, high-resolution flatbed scanners have become available. With a resolution in excess of 1000 ppi, standard flatbed scanners rival the accuracy of traditional measurement devices such as calipers. We investigate the use of an inexpensive flatbed scanner for making rapid measurements of the dimensions of simple objects, and compare the measurements with reference measurements made with a high-caliber Optical Coordinate Measuring Machine, a device that is orders of magnitude more expensive. Using such a device will open up costly, labor intensive precision measurements to anyone. Initial results on components to be used in the Mu2e experiment promise measurements with an accuracy of $\pm 0.050$ mm and rapid turn around. [Preview Abstract] |
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K1.00041: Residual stress analysis with Opto-Acoustic Method. Fumiya Miura, Tomohiro Sasaki, Masaru Usui, Sanichiro Yoshida, Shuichi Sakamoto A nondestructive method to analyze welding-induced residual stresses is proposed. The proposed method consists of acoustic and optical techniques. The acoustic device (scanning acoustic microscope or contact acoustic probe) is used to measure the acoustic velocity of the specimen. According to acoustoelasticity, ~compressive/tensile residual stresses increase/decrease acoustic velocity. The optical device (Electronic Speckle-Pattern Interferometer, ESPI) detects acceleration due to a low-level tensile load (approximately a quarter of the yield stress) applied by a test machine. According to the theory of harmonic oscillation, masses have positive/negative acceleration when they move toward/from the equilibrium location. The acoustic and optical measurements have been performed on butt-welded aluminum alloy specimens (20 mm x 50 mm, 5 mm thick) on a point-by-point basis, and the acoustic and optical results are compared with each other. For most specimens, the acoustic and optical measurements appear consistent with each other. Our final goal is to make this method totally nondestructive and quantitative. [Preview Abstract] |
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K1.00042: Enhancement of $\beta $-phase in PVDF films embedded with ferromagnetic Gd$_{\mathrm{5}}$Si$_{\mathrm{4}}$ nanoparticles for piezoelectric energy harvesting Shane Harstad, Noel D'Souza, Navneet Soin, Ahmed El-Gendy, Shalabh Gupta, Vitalij Pecharsky, Tahir Shah, Elias Siores, Ravi Hadimani Self-polarized Gd5Si4-polyvinylidene fluoride (PVDF) nanocomposite films have been synthesized via a facile phase-inversion technique. For a 5 wt{\%} Gd5Si4-PVDF film, the enhancement of the piezoelectric $\beta $-phase from 49{\%} for pristine PVDF to 81{\%} for nanocomposite is confirmed using FTIR spectroscopy. The Gd5Si4 particles prepared using high-energy ball milling have a particle size of \textasciitilde 470 nm with a high magnetization of 11 emu/g. The analysis of the Gd5Si4-PVDF films revealed a change from diamagnetic behavior to enhanced ferromagnetism when pristine PVDF films are loaded with 2.5 wt{\%} and 5 wt{\%} Gd5Si4 nanoparticles. The increased $\beta $-phase fraction resulting from the addition of magnetic Gd5Si4 nanoparticles to membranes of PVDF paves the way for future efficient energy harvesting applications using a combination of magnetic and piezoelectric effects. [Preview Abstract] |
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K1.00043: Adhesion of of Au thin Films on PMMA and Other Substrates Yvonne Kinsella, Wm. Christopher Hughes, Luis Royo-Romero, Brian Augustine, Xiaofeng (Harry) Hu The adhesion of Au onto polymer surfaces has important applications in the aerospace and automotive industries, microelectronics, and the fabrication of microfluidic devices. Au is desirable for such applications due to its corrosion resistance as well as its excellent conductivity of heat and electricity. Unfortunately, the inertness of gold results in a poor adhesion to polymer surfaces such as PMMA. In previous work in our lab we have developed a method to quantify exactly how well Au adheres to PMMA. Thin layers (approx. 10-20nm) of Au are deposited onto 1in square pieces of PMMA and then polished with increasing amounts of pressure until the Au is removed. After each polishing step, the transparency of the Au film is determined by using a UV/Vis spectrophotometer or by counting the pixels after scanning a photo of the sample. In this study we have expanded to apply this method to Au thin films on glass, as well as Au/Cr thin films on glass. Testing glass is the first step towards testing other polymer substrates than PMMA, which will be equally as useful to the aforementioned applications. [Preview Abstract] |
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K1.00044: Ferro-lattice-distortions in Bismuth Sulfide Superconductors Anushika Athauda, Despina Louca, Christina Hoffman, Yang Ren, Xiangde Zhu, Saicharan Aswartham, Jasminka Terzic, Gang Cao, Yoshikazu Mizuguchi, Osuke Miura, Keita Deguchi, Yoshihiko Takano, Masanori Nagao ReO$_{\mathrm{1-x}}$F$_{\mathrm{x}}$BiS$_{\mathrm{2}}$ (Re $=$ La, Nd and Pr) is an electron-phonon coupled superconductor with the maximum transition temperature of 10.8 K in LaO$_{\mathrm{1-x}}$F$_{\mathrm{x}}$BiS$_{\mathrm{2}}$ at x $=$ 0.5. The parent phases, ReOBiS$_{\mathrm{2}}$ (Re $=$ La, Nd and Pr) compounds are either bad metals or insulators. The crystal structure of ReO$_{\mathrm{1-x}}$F$_{\mathrm{x}}$BiS$_{\mathrm{2}}$ is investigated using single crystal neutron and synchrotron X-ray diffraction experiments. In all compositions, a superlattice Bragg pattern was observed on hk0 plane. The Bragg patterns challenge the long-presumed nominal symmetry of BiS$_{\mathrm{2}}$ superconductors P4/nmm, and other theoretically suggested symmetries. The Bragg structure can be reproduced by a model involving coherent in-plane displacements of the sulfur in superconducting BiS$_{\mathrm{2}}$ planes. The sulfur displacements produce different Bi-S bond lengths in-plane giving rise to charge fluctuations. The lattice distortions that arise from unstable phonon modes can trap the charge carriers decreasing the number of pairing electrons. [Preview Abstract] |
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K1.00045: Functionality of Chloroform Treatment to Improve Adhesion of Deposited Au Thin Films on PMMA Luis Royo Romero, Yvonne Kinsella, Brian Augustine, Wm. Christopher Hughes The deposition of Au thin films onto polymer surfaces is a crucial step in the fabrication of a variety of microfabricated devices including displays, microelectronics, biomedical and microfluidic devices. Au is characterized by having high electrical and thermal conductivity making it a good choice for micro-electrodes. However, due to its relative chemical inertness, it is difficult to fabricate on polymeric substrates due to the low adhesion to polymer's surface. Previous experiments have studied various methods to improve the adhesion of vapor-deposited Au thin films onto poly (methylmethacrylate) (PMMA). In this study, we deposit 14 nm of Au onto 1.50 mm thick PMMA via magnetron sputter deposition and exposed the samples to a chloroform vapor in a chamber at 70\textdegree C using a hot plate. The force required to remove the Au thin film is quantified as a function of the polishing force and the transmittance acquired using UV-VIS spectroscopy. Conducive of data confirming the effectiveness of chloroform post-treatment, we conducted a study on selective pattering by isolating regions using PDMS masks and attaining quantitative data by pixel counting using a Matlab script. Both methods demonstrate a similar inverse relation, the reduction of Au on the PMMA as incremental of applied force, displaying the potency of chloroform exposure. [Preview Abstract] |
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K1.00046: Electronic Structure Calculations of Iron-doped Zinc Selenide Evan Garrison, Kyle Bentley, Ryoichi Kawai II-VI semiconductors doped with transition metal ions are good candidates for mid-infrared laser materials. Among them, iron-doped zinc selenide (Fe:ZnSe) appears to be one of the most promising. However, its detailed properties are still not well understood. We have investigated the electronic and geometric structures around the Fe ion dopant in ZnSe using density functional theory. The geometry around substitutional and interstitial dopants are fully optimized using a large supercell consisting of 217 atoms. First, we confirmed that Fe$^{2+}$ with quintet spin (S=2) is the most stable state. The lattice distortion around the dopant is found to be very small. We identified two electronic orbits inside the band gap which are used in the laser application. We found the excitation energy to be 0.329 eV, consistent with the experimental data. The upper state is very close to the conduction band, suggesting that the excited electron may go to the conduction band. [Preview Abstract] |
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K1.00047: Thickness dependence of weak localization in thin films of Ni/Cr alloy Kyle Vivian, Phillip Broussard In order to study the weak localization effect in thin films, Ni and Cr were simultaneously deposited using DC magnetron sputtering onto sapphire substrates at 573 K. These thin films ranged from $\approx$ 100 nm to 0.3 nm and contained $\approx$80/20 Ni/Cr by weight. The samples were then cooled from room temperature to $\approx$ 6 K in order to measure the sheet resistance (measured using the standard Van der Pauw technique) vs. the temperature of the sample. Normal metalic behavior during cool down is observed in thicker films. However, the films exhibitted a metal-insulator transition at a particular tempurature which increased as film thickness was decreased. This transition can be attributed to the electrons becoming weakly localizing as different scattering behaviors begin to dominate. [Preview Abstract] |
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K1.00048: Superlattice Formation and Charge Density Waves in TiSe$_{\mathrm{2-x}}$Te$_{\mathrm{x}}$ Aaron Wegner, Junjie Yang, Despina Louca Charge density waves (CDW) are spatial modulations of electron density that are accompanied by a periodic lattice distortion that creates a superlattice. CDWs are common in layered structures such as transition metal dichalcogenides such as TiSe2, which undergoes a prototypical CDW transition below 200K. The mechanism behind the phase transition has not yet been settled. Neutron scattering experiments were carried out at NOMAD at Oak Ridge National Lab to investigate the effect of tellurium doping on the CDW transition in TiSe$_{\mathrm{2-x}}$Te$_{\mathrm{x}}$. Data analyzed using real space pair distribution function analysis shows that the local structure cannot be adequately described using the average structure obtained by Rietveld refinement as peak splitting indicates ordering of the Se and Te atoms and a monoclinic unit cell (space group P2/m) that differs from the nominal hexagonal unit cell (P$\overline 3 $m1). Neutron diffraction experiments from BT-1 at the NIST Center for Neutron Research investigating the compositional and temperature dependence of the structure shows a superlattice structure in TiSe$_{\mathrm{2-x}}$Te$_{\mathrm{x}}$ for x $=$ 0.2, 0.25, and 0.5, indicating that superlattice formation is robust to Te doping. [Preview Abstract] |
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K1.00049: Sequence-Structure-Property Relationships in Polymeric Proteins: Thermo-optic Properties and Device Applications Chester Szwejkowski, Huihun Jung, Abdon Pena-Francesch, John Tomko, Benjamin Allen, Sahin Ozdemir, Patrick Hopkins, Melik Demirel Proteins are a natural source of building blocks for designing biological materials. Polymeric (i.e., repetitive) proteins are key to the creation of many designer materials with programmable flexibility, biocompatibility, superior optical properties, energy efficiency, and mechanical strength. We report the development of a novel technique to screen protein crystallinity quantitatively based on laser-probing. First, we show theoretically that the temperature dependence of the refractive index of a polymeric protein is correlated to its crystallinity. Then, we performed time-domain thermo-transmission experiments on purified semi-crystalline proteins, both native and recombinant (i.e., silk and squid ring teeth), and also on intact E. coli cells bearing overexpressed recombinant protein. Ultimately, this allows us to quantify rapidly the crystallinity of a protein sample using time-domain thermo-transmission spectroscopy by decoupling volumetric thermal expansion from its structural response at room temperature. Successful development of this technique for polymeric proteins will have a significant impact on multiple applications in various fields (e.g., materials science, agriculture, neurological diseases and medicine) and open new avenues of protein research. [Preview Abstract] |
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K1.00050: Undergraduate Research Experience: Electrical conductivity of novel amorphous Fe-Tb-Dy-O thin films. Alexandra Waters, Tatiana Allen, Humaira Taz, Ramki Kalyanaraman We studied electrical properties of novel amorphous ternary oxides of chemical composition (Me)$_{\mathrm{2}}$O$_{\mathrm{3}}$, where primary metal (Me) was iron, along with two lanthanides, terbium and dysprosium. The material was recently reported [1] to show a combination of very high optical transparency, electrical conductivity, and Hall mobility. The mobility values observed in this material are comparable to the best indium-based transparent conductive oxides, and considerably higher than mobility in amorphous silicon. The material may be very promising for electronic applications. We studied resistivity (by van-der-Pauw method) and the Hall mobility of the films deposited by electron beam co-evaporation. We also studied the evolution of electrical conductivity of the material with repeated thermal cycling between 290 and 700K. [1] Malasi A. \textit{et al}. Novel Iron-based ternary amorphous oxide semiconductor with very high transparency, electronic conductivity, and mobility. \textit{Sci. Rep.} \textbf{5}, 18157; doi:10.1038/srep18157(2015). [Preview Abstract] |
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K1.00051: In Situ Characterization of Optically Transparent Polymer and Dye pH Sensing Films Daniela Topasna, Scott Cox, Troy Emig We present the results from \textit{in situ} characterization of ionically self-assembled monolayers (ISAM) pH sensing films. These types of films have potential applications in the biomedical field and as optical pH sensors. The films are fabricated by alternate immersion of transparent substrates in aqueous solutions of poly(allylamine hydrochloride) and Direct Yellow 4. The absorption of the film changes when the pH of the surrounding medium changes. We describe the steps in creating the experimental set-up, the fabrication process of the optically transparent films, and the results of the pH dependent absorption measurements. [Preview Abstract] |
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K1.00052: Electric Field Effect on the Magnetic Order in Multiferroic LuMnO$_{\mathrm{3}}$ Chunruo Duan, Junjie Yang, Despina Louca, Leland Harriger Multiferroic materials have been intensively studied in recent years. The main focus lays on the coupling of the ferroelectric and magnetic orders. Among the varieties of the multiferroics is the rare-earth manganites LuMnO$_{\mathrm{3}}$, with a hexagonal P6$_{\mathrm{3}}$cm crystal structure. This structure consists a triangular layer of Mn$^{\mathrm{3+}}$ with S$=$2, surrounded by O$^{\mathrm{2-}}$ ions in a bipyramid local structure, and the rare-earth element goes in between the layers, making the intralayer spin-spin interaction stronger than the interlayer spin-spin interaction. Although geometrically frustrated, the spin on Mn ions can order antiferromagnetically at T$_{\mathrm{N}}$ \textasciitilde 90 K. The ferroelectric transition, on the other hand, happens at much higher temperature (T$_{\mathrm{E}}$ \textgreater 900 K) with the ion displacement in the c direction. Despite the fact that these two transition temperatures are well separated, our neutron scattering experiments on single crystal LuMnO$_{\mathrm{3}}$ carried at SPINS at NCNR demonstrate an electric field effect on magnetic peak intensity. This electric field effect on magnetic peaks can be explained by the coupling of ferroelectric domain walls and AFM walls, and a Monte Carlo simulation with the domain wall coupling is able to reproduce the observed effect. [Preview Abstract] |
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K1.00053: Entropy of Exciton Formation in 2D Atomic Layer Transition Metal Dichalcogenides Quinton Rice, Tikaram Neupane, Dulitha Jayakodige, Bagher Tabibi, Felix Seo The 2-dimensional atomic layer transition metal dichalcogenides (TMDCs, MX$_{\mathrm{2}}$; M$=$Mo or W; X$=$S, Se, or Te) are of special importance for optoelectronic applications because of the structural tunability of bandgaps in visible and near-infrared regions and the bandgap crossover from direct (monolayer) to indirect (bilayer or multilayer). The role of the acoustic phonon energy and electron-phonon coupling which is critical to the formation of excitons is investigated using the O'Donnell and Chen relation for temperature-dependent bandgaps of semiconductors. The change in entropy of exciton formation is given by the derivative of the O'Donnell and Chen relation when the bandgap energy is the standard Gibbs free energy. The analysis suggests the change in entropy of exciton formation with higher energy phonons (100 meV) is constant until 90 K while lower energy phonons (10 meV) approaches a constant value of $-2Sk_{B} $ between 250 K and 300 K where$S$is the strength of electron-phonon interaction and $k_{B} $is the Boltzmann constant. Increased scattering and spontaneous decay probabilities of higher energy phonons may result from the larger electron-phonon interaction of less energetic phonons. A \textasciitilde 3-fold increase in the change in entropy of exciton formation was observed while the electron-phonon coupling strength largely determines the bandgap energy compared to the average acoustic phonon energy. Acknowledgement: This work at HU is supported by ARO W911NF-15-1-0535, NSF HRD-1137747, and NASA NNX15AQ03A. [Preview Abstract] |
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K1.00054: Polarity Change of Nonlinear Absorption between Monolayer and Bilayer/Multilayer Tikaram Neupane, Quinton Rice, Dulitha Jayakodige, Bagher Tabibi, Felix Seo The monolayer of TMDC has a direct bandgap which is wider than the indirect bandgap of the bilayer/multilayer. The bandgap can be modified based on the number of layers and the temperature. The change of bandgap plays an important role in the nonlinear absorption process which can be illustrated through the Jablonski diagrams. Two-step absorption with one photon for each step, two-photon absorption to the real final state through a virtual intermediate state, and two-photon excitation to the virtual final state through a virtual intermediate state are all included in the nonlinear absorption process. The allowed electric dipole transition $\left| \right.i\left. \right\rangle \to \left| \right.f \left. \right\rangle $between the two states in the one-photon excitation is due to different parities. Saturable (negative) absorption (SA) occurs when the ground-state absorption cross-section is higher than the excited-state absorption cross-section, $\sigma_{g} >\sigma_{e} $. Alternatively, the allowed electric dipole transitions $\left| \right.i\left. \right\rangle \to \left| \right.m\left. \right\rangle $and $\left| \right.m\left. \right\rangle \to \left| \right.f \left. \right\rangle $between the initial and final states in the two-photon excitation are due to the same parities. The reverse saturable (positive) absorption (RSA) becomes dominant when the excited state absorption cross-section is higher than the ground-state absorption cross-section, $\sigma_{e} >\sigma_{g} $. Atomic layers that show SA are utilized for laser Q-switching and mode-locking, while the atomic layers which demonstrate RSA are utilized for optical power limiting. Acknowledgements: This work at HU is supported by NSF HRD-1137747, ARO W911NF-15-1-0535, and NASA NNX15AQ03A. [Preview Abstract] |
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K1.00055: Spin Coated Arsenic Selenide Thin Films: Preparation and Characterization. Maria White, Caity Thomas, Joshua Allen, Jonathan Bunton, Andriy Kovalskiy Chalcogenide glasses exhibit unique physical properties that make them favorable in many optical applications. High quality arsenic selenide chalcogenide glass thin films can be made by spin coating. This method is based on chemical dissolution of bulk arsenic selenide glasses in ethylenediamine. Such homogenous films have structure very similar to the bulk counterpart. As a result, it is expected that they should be photo-stable at the irradiation by visible light. Technological features of spin coating method for the arsenic selenide were studied. It was found that chemical environment plays an essential role in the process of preparation of the films of high optical quality. The best films have been obtained in inert gas environment with minimum contact with oxygen. Raman spectroscopy was used for structural characterization of the prepared samples. Photo-induced optical effects were studied by irradiating the thin chalcogenide film with light of different energies and intensities. [Preview Abstract] |
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K1.00056: Diffusive Phase Change Model of Twitter Information in the Context of a Cusp Catastrophe. Keith Andrew, Morgan Taylor, Karla Andrew, Phillip Womble For large sample populations social media information transmission can statistically obey patterns that can be modeled as diffusive wave phenomena. In particular Twitter messaging provides limited character range full searchable data sets with links provided by various hashtags and retweets. The complexity of the interconnectivity of the links can be expressed through a nodal graph and its equivalent matrix representation. Often the overall group Tweeting behavior in this representation is smooth and continuous over a large range of time scales, however some events can occur that lead to discontinuous changes in Tweet/Retweet behavior. Following Johnson we model this behavior as a phase change from one type of tweeting activity to another. We use the standard cusp catastrophe as an example of phase change behavior with two control dimensions. The potential function can exhibit first and second order phase transitions as described by a generalized Ginzburg-Landau motivated model. Here we identify the parameter space for a Tweet invoked phase transition corresponding to a sudden change in retweets. We identify the classical phase change critical curve and map this to the cusp catastrophe by taking the phase diagram as the projective base space of the cusp. . [Preview Abstract] |
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K1.00057: Diffusive Dynamics on a Network Madhurima Nath, Yihui Ren, Yasamin Khorramzadeh, Stephen Eubank The effect of the topology of a finite sized interacting system, modelled into a network, on its dynamics is an interesting question. Various methods have been proposed in the literature for building different equivalence classes or families of networks based on the structural aspects of the system. It is observed that similarities in the local statistics of two networks are not sufficient to predict the dynamics on them. We suggest a global statistic, the Moore and Shannon's network reliability polynomial that depends on both the structure and the dynamics to explore the behaviour of a diffusive process on a network. It gives the probability that a system composed of many different interacting components has a desired property. The computation of the reliability polynomial exactly is often NP-hard, but estimating it using Monte-Carlo simulation is feasible even for graphs with hundreds of millions of edges. The probabilistic nature of the polynomial allows the mapping of parameters of one network on to another using a simple transformation inspired by renormalization group approaches that keeps the dynamical phenomenon invariant. [Preview Abstract] |
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K1.00058: Optimizing MCMC Method for Reaction Cross Section Calculations Keiti Rueter, Ivan Novikov Monte Carlo methods are computational algorithms based on random sampling that return numerical results. This family of methods are used generally for drawing samples from predefined probability distributions, such methods are commonly used in finance, applied math, and computational physics. The Markov Chain Monte Carlo method rather than using statistically independent random samples like a general Monte Carlo method, uses correlated samples based on the previous point. Autocorrelation time and power spectra of the random number chain provide diagnostics that can be used to optimize the quality of the chain and minimize integration error. A chain of good quality will adequately cover the whole distribution reliably, returning results of numerical integration with maximum accuracy. In the presented work, we demonstrate how variation in quality of the random number sequence affects results of the reaction cross section calculations in the Glauber Model framework for various light nuclei with A less than 40. [Preview Abstract] |
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K1.00059: Ray optics method for tracking of hydrogel particles and its applications in erosion experiments Stella Wang, Yuchen Zhao, Robert Behringer The ray optics method is a technique that creates two-dimensional projections for three-dimensional transparent objects. When a transparent sphere is placed in a fluid with a slightly lower refractive index, the ray optics method implies that the sphere will project a circle with a dark outer ring. We investigate the potential application of the ray optics method in the study of three-dimensional granular systems and erosion. The experimental setup consists of a point source, a Plexiglas box filled with hydrogels and deionized water. We subject the hydrogels to a shear stress that is induced by stirring the top of the water. We verify that the ray optics method accurately displays the position of the hydrogels even when they are entrained in fluid flow. Our experiments demonstrate that ray optics can be used as an inexpensive method to find bed height and track particle positions and velocities over time. [Preview Abstract] |
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K1.00060: Feedback Loops in Ultrasensitive Cascades Syed Jibran Haider Understanding the flow of signals through stochastic bio-circuits of molecular interactions is important for both systems and synthetic biology. Here we analyze the stochastic signals produced by a bio-circuit that contains a feedback loop. The bio-circuit we study is a modification of the ultrasensitive mitogen-activated protein kinase (MAPK) cascade. The analysis is based on moment closure technique based on a novel procedure of splitting nonlinear nodes that represent product interactions in the bio-circuit's molecular diagram. [Preview Abstract] |
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K1.00061: Effect of Anatomical Variability in Brain on Transcranial Magnetic Stimulation Treatment Farheen Syeda, Hamzah Magsood, Erik Lee, Ahmed El-Gendy, David Jiles, Ravi Hadimani Transcranial Magnetic Stimulation is non-invasive clinical therapy for depression and migraine, and shows promise as treatment for Parkinson's disease, Alzheimer's disease, and other neurological disorders. However, it is yet unclear as to how anatomical differences may affect stimulation from this treatment. We use finite element analysis to model and analyze the results of Transcranial Magnetic Stimulation in various head models. A number of heterogeneous head models have been developed using MRI data of real patients, including healthy individuals as well as patients of Parkinson's disease. Simulations of Transcranial Magnetic Stimulation performed on 22 anatomically different models highlight the differences in induced stimulation. A standard Figure of 8 coil is used with frequency 2.5 kHz, placed 5 mm above the head. We compare cortical stimulation, volume of brain tissue stimulated, focality, and maximum E-field induced in the brain for models ranging from ages 20 to 60. Results show that stimulation varies drastically between patients of the same age and health status depending upon brain-scalp distance, which is not necessarily a linear progression with age. [Preview Abstract] |
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K1.00062: Room temperature ferromagnetic Gd$_{\mathrm{5}}$Si$_{\mathrm{4}}$ nanoparticles as T2 contrast agents for MRI. Ahmed El-Gendy, Shane Harstad, Shalabh Gupta, Vitalij Pecharsky, Vimalan Vijayaragavan, Jamal Zweit, Ravi Hadimani Room temperature ferromagnetic Gd$_{\mathrm{5}}$Si$_{\mathrm{4}}$ nanoparticles were synthesized using arc-melting and ball milling. We have demonstrated that these particles can be used as improved contrast agents for magnetic resonance imaging. The ball milled Gd$_{\mathrm{5}}$Si$_{\mathrm{4}}$ nanostructured material shows ferromagnetic to paramagnetic transition near 340 K revealing long range magnetic order of Gd$_{\mathrm{5}}$Si$_{\mathrm{4}}$ phase. The phase structure and the magnetic measurements yield orthorhombic Gd$_{\mathrm{5}}$Si$_{\mathrm{4}}$ with magnetization of 45 emu/g. Echo time was measured in a 7T MRI system showing significant reduction compared to the superparamagnetic iron oxide nanoparticles. Such results show the potential of Gd$_{\mathrm{5}}$Si$_{\mathrm{4}}$ ferromagnetic nanoparticles as T2 contrast agent for magnetic resonance imaging. However these particles did not show reduction in T1 times. [Preview Abstract] |
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K1.00063: Amino Acid Propensities for $\alpha $ to $\beta $ Secondary Structural Conversion Norma Peña Flores, Camila Uzcategui, Prem Chapagain, Bernard Gerstman Numerous proteins undergo an alpha-helix to beta-sheet conversion, which can then lead to the formation of toxic amyloid fibrils. The resulting fibrous protein aggregation is associated with the pathology of many debilitating illnesses and neurodegenerative disorders, such as type II diabetes, Alzheimer's disease, and Parkinson's disease. Many factors determine the preference that an amino acid has to assume an $\alpha $-helix versus $\beta $-strand secondary structure. We use Replica Exchange Molecular Dynamics computer simulations to study the amino acids that make up the small, engineered protein cc$\beta $ that undergoes similar structural transitions as amyloid proteins. We examine the propensities for the various pairs of amino acids in cc$\beta $ to form specific secondary structures as a function of temperature. [Preview Abstract] |
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K1.00064: Development of Brain Phantom for Neuromodulation and Neuroimaging Ciro Alcoba Serrate, Erik Lee, Ravi Hadimani We are developing a method to 3D print an anatomically/physically accurate human head phantom with same electrical properties of the human head. This Phantom is being developed for evaluating Transcranial Magnetic Stimulation procedures used in treatment of neurological disorders. Its development could have many applications in the medical field such as Deep Brain Stimulation training. The plan for fabricating this head phantom is to create shells for the brain parts. Today's 3D printing technologies we are limited to materials that have predefined electrical conductivity and magnetic. 3D printing technology has not been able to provide a printer that allow us to modify the electromagnetic properties of the materials. Shells of the parts of the head are being printed to fill these hollowed gaps in the shells with composite gels that mimic the electromagnetic properties of different parts of the brain. So far we have been able to print individually every single part of the brain in shells and half assemblies of some parts of brain. Shells are created from MRI images of brain scans and editing them using a mesh-mixer. This software will be used to assemble these parts of the brain to be printed that will enable use of phantom head for neuroimaging/neuromodulations applications. [Preview Abstract] |
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K1.00065: Scenario Theory (Simulated Reality Evidence) Ahmad Reza Estakhr Scenario theory is about a series of suspicious astrophysical events that (it seems) projected to occur by an unknown Scenarist. for example, All stars release Big Bang's energy which is stored at Hydrogen atom, It is really suspicious Astrophysicsl process, Why Hydrogen atom is so stable? It is proposed that our universe is simulated to follow the scenario and there are things that even its scenarist is unaware of them, and it is the mean reason why scenarist simulated our world. [Preview Abstract] |
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K1.00066: Catalytic Nanofusion and Relativized Minimality. Andi-Asri Arief,dr-SpKJ, Lukas Widjaja, SE Accompanies ``the Energy thus produced is enormous, and because deuterium is very cheap in the form of heavy water ( less than US {\$} 1/ gm ), the fuel cost for this process is very low indeed ( much less than 1 cent per KwH )''- L.C. Case, ScD: \textbf{``Catalytic Fusion of Deuterium to He-4''- }Salt LakeCiy, 1998 to Casey Stengels through Patria y Libertad and catalytic nanomotors as well as @ Rp. 500. 00 \textit{itik alis } Indonesian 1998 official stamp henceforth proposes ``\textbf{the catalytic NanoFusion'' }whereas inherently not yet exploitetated by PT. ADARO Energy, tbk of shale gas {\&} ``CoalBedMethane'' as unconventional gas. Occassionaly, from DjaluGurruwiwi of Grothendiek-Riemann-ROCH of I made Kaler/Arakelov geometry of Roessler/Rossby bifurcation-whistle we offers Luigi Rizzi:'' \textbf{Relativized Minimality'' } to the syntax of Relativization ever retrieved by HE. Mr. Rizal Adi Prima,PhD/Richard Di-PRIMA bindings with Richard Courant. [Preview Abstract] |
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K1.00067: Magnetic Field Table Approximations using Chebyshev Polynomials Paul Ellison, Michael Tiefenback At the Thomas Jefferson National Accelerator Facility (JLab) a pair of Linear Accelerators (LINACs) are in operation that are connected by two arcs in a racetrack design. The arcs of the accelerator beam line at JLab bend the electron beam using a set of dipole steering magnets. Measurements of magnetic field strength as a function of current were taken on these magnets and compiled into field tables in order to approximate the field intensity using a linear piece-wise interpolation, which is necessary for beam operation. The interpolation used to approximate the intensity introduces errors at currents where the field behaves non-linearly, and so the goal is to find physically reasonable supplementary points to fill in these tables to reduce the interpolation error, as well as to estimate the fit error of the approximation. This was done using a Chebyshev polynomial representation to make a smooth approximating function where the fit error could be easily estimated. The present error estimate is a work in progress and future work will include comparing the approximation to other interpolation methods, and taking into account hysteretic behavior at low operational currents. [Preview Abstract] |
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K1.00068: The JAM Derivative Matthew W. Pearson, S. Kyle Castleberry, Sharon L. Careccia, Hong Yue, Ralph H France III In Quantum Mechanics the derivative is an anti-hermitian operator in Hilbert Space. In this space this operator can be represented by an infinite dimensional matrix. Considering this, some questions were raised about what could be done with this matrix representation. Letting $D$ represent the derivative operator, we have that $DD=D^2$ represents the second order derivative operator, and thusly $D^n$ represents the $n$th order derivative operator. Non-integers orders have been considered since the beginning of Calculus. With these defined, it is interesting to consider non-constant orders of differentiation. Letting $f(x)$ be some function, it is interesting to consider the case $D^{f(x)}$, the case of an operator which acts as a derivative of order $f(x)$. Since Quantum Mechanics deals with state vecotrs in a complex space, we shall define this operator using fourier transforms on functions expanded into fourier series. We thus have an an operator from the set of complex functions to itself with utility for any periodic or bounded real or complex function. We notate this new operator $J^{\alpha_m}$, since within these parameters the operator acts as a multi-ordered variant of the integral operator. [Preview Abstract] |
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K1.00069: Optimized simulations of Olami-Feder-Christensen systems using parallel algorithms Eric Montag, Rachele Dominguez, Rance Necaise The sequential nature of the Olami-Feder-Christensen (OFC) model for earthquake simulations limits the benefits of parallel computing approaches because of the frequent communication required between processors. We developed a parallel version of the OFC algorithm for multi-core processors. Our data, even for relatively small system sizes and low numbers of processors, indicates that increasing the number of processors provides significantly faster simulations; producing more efficient results than previous attempts that used network-based Beowulf clusters. Our algorithm optimizes performance by exploiting the multi-core processor architecture, minimizing communication time in contrast to the networked Beowulf-cluster approaches. Our multi-core algorithm is the basis for a new algorithm using GPUs that will drastically increase the number of processors available. Previous studies incorporating realistic structural features of faults into OFC models have revealed spatial and temporal patterns observed in real earthquake systems. The computational advances presented here will allow for studying interacting networks of faults, rather than individual faults, further enhancing our understanding of the relationship between the earth's structure and the triggering process. [Preview Abstract] |
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K1.00070: Computation in Physics: Resources and Support Larry Engelhardt We will describe exciting new resources and support opportunities that have been developed by ``PICUP'' to help faculty to integrate computation into their physics courses. (``PICUP'' is the ``Partnership for Integration of Computation into Undergraduate Physics''). These resources include editable curricular materials that can be downloaded from the PICUP Collection of the ComPADRE Digital Library: www.compadre.org/PICUP. Support opportunities include week-long workshops during the summer and single-day workshops at national AAPT and APS meetings. [Preview Abstract] |
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K1.00071: X-Ray Diffraction: Geiger-M\"{u}ller Tube Experiments Nicholas Tomlinson, Chace Covington, Seth Smith X-ray experiments were performed with the Leybold Didactic Model 554801 X-Ray Apparatus with a Molybdenum anode. The experiments performed include Bragg's Law, the Duane-Hunt relation, Planck's Constant, and Moseley's Law and the Rydberg constant. X-ray filtering and the energy spectrum of an X-ray tube as a function of voltage and current were also observed. The results of these experiments and the performance of the x-ray apparatus will be presented. [Preview Abstract] |
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K1.00072: Scaffolding Interdisciplinary Classical Mechanics using Snack Foods and Household Liquids Chelsea Dandridge, Rebecca Skelton, Kenneth Pestka, II Scaffolding is an instructional technique that is used to move students progressively toward better understanding and greater independence in the learning process. A component of scaffolding is to present the conceptual ideas about a topic and then gradually increase difficulty and inter-connect physics concepts. The scaffolding technique was applied to the experiments presented here, which focused on maple seeds, various snack foods, and household liquids. For example, the Young's Moduli of Twizzlers, Cheetos Puffs, Cheetos Crunchy, and pretzel sticks were calculated using Euler beam theory and the cantilever method. In another experiment, the parallel axis theorem was used to calculate the moment of inertia of maple seeds, and a motion sensor and high-speed camera were used to analyze the kinematics and rotational motion of falling seeds. Experiments were conducted to measure the mass and density of different household liquids, as well as determine viscosity by measuring the terminal velocity of a marble dropped in each substance. In addition, the density and viscosity were used to calculate the Reynolds number for each fluid. All experiments included the use of video analysis in order to measure variables needed for calculations. One of the main goals of this research was to design experiments with common, everyday objects people are familiar with, in order to increase interest in learning physics and performing experiments. [Preview Abstract] |
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K1.00073: Scaffolding Laboratory Activities Utilizing Everyday Biological Materials, such as Eggs, Popcorn, and Common Liquids, to Demonstrate Classical Mechanics Concepts Rebecca Skelton, Chelsea Dandridge, Kenneth Pestka, II Using easily accessible biological objects such as eggs, popcorn, and common liquids, we designed and implemented laboratory experiments focusing on classical mechanics concepts, which included the conservation of momentum, conservation of energy, kinematics, sound intensity level and power. We also produced handouts and activities that were designed to coincide with the lab experiments. The handouts included instructions, a list of materials, and conceptual questions to help students internalize the new information. Our experiments used a scaffolding technique, by taking related concepts that students learned in previous labs and activities, and integrating them in subsequent labs. Activities were designed to help students stay focused on the lesson, and absorb and retain relevant content. In addition, the labs and activities were designed to be accessible to individuals with varying mathematical backgrounds. Our goal was to use common household materials in order to ignite a love for physics, and encourage students to discover the relevance of physics in daily life. [Preview Abstract] |
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K1.00074: A Study of Women's Self Defense Strikes Zachary Barnes, Christopher Barnett, Alexandra Waters, Robert Marlowe The need for, and appeal of, women's self-defense programs has rapidly become one of the more popular trends in America. Many of these courses are taught by different schools of thought and are based upon various methods, with so many different techniques being taught as absolutes a scientific viewpoint is paramount to our understanding of self-defense. This study will focus on testing the feasibility of 3 different strikes by using approximately 200 female volunteers with no prior experience in self-defense or martial arts. Our overall goal is to find the strike that is most effective after a single class (as most of these courses last a mere few weeks to only six months) and discover trends from various body-types and age-groups. The vertical punch, twist punch, and open-hand palm-strike will be taught to the participants during a course lasting 30-45 minutes, then each participant will have her strikes measured via a pad fitted with a pressure sensor. After all data has been collected, the instructors teaching each strike will be fitted with motion tracking suits and the techniques will be captured via a tracking program. A skeletal structure will be applied and the body mechanics will be examined from a classical (Newtonian) mechanics perspective. [Preview Abstract] |
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K1.00075: Silicon Photomultiplier Optimization and Performance Nina Mazzarelli As part of prototype testing for the Mu2e cosmic ray veto shield, the impact of silicon photomultiplier (SiPM) performance was studied over a range of experimental conditions. SiPMs were exposed to LED light pulses to determine response linearity as a function of exposed light intensity. Using the same light source, the dependence of photoelectron timing resolution on applied bias voltage was measured. The relationship between radiation exposure from a Cs-137 source and SiPM and electronic crosstalk levels was also measured. Other phenomena, including the contribution of after-pulsing and double peak resolution to readout resolution, were modeled as a function of time, amplitude, and over-voltage. [Preview Abstract] |
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K1.00076: Optical Properties of Plasmon-coupled CuInS$_{\mathrm{2}}$ and CuInS$_{\mathrm{2}}$/ZnS Quantum Dots Quinton Rice, Sangram Raut, Rahul Chib, Zygmunt Gryczynski, Ignacy Gryczynski, Wan-Joong Kim, Sung-Soo Jung, Bagher Tabibi, Felix Seo Plasmon-coupled CuInS$_{\mathrm{2}}$ (CIS) and CuInS$_{\mathrm{2}}$/ZnS (CIS/ZnS) quantum dots (QDs) exhibit broad emission spectra and large PL enhancement that provides a great opportunity for the development of hybrid white light-emitting-diodes (LEDs). Plasmon-coupled excitons at the surface-/interface-, shallow-, and deep-trapped states of CIS and CIS/ZnS revealed spontaneous emission enhancement. The enhancements of plasmon-coupled CIS QDs were 2.4-folds compared to CIS while plasmon-coupled CIS/ZnS QDs exhibited 27.3-folds compared to CIS/ZnS. Large PL enhancement signifies the reduction of non-radiative due to the strong local field of Au NPs and the competing plasmon-coupling decay rate. Plasmon-coupled CIS/ZnS exhibited larger PL enhancement compared to plasmon-coupled CIS due to the increased spontaneous emission enhancement resulting from the reduction of non-radiative decay. Plasmon-coupled CIS and CIS/ZnS are excellent candidates for hybrid white LEDs due to the increased radiative decay by the localized surface plasmon resonance, the broad PL from CIS and CIS/ZnS, and good spectral coupling of blue diode excitation. Acknowledgement: This work at HU is supported by NSF HRD-1137747, ARO W911NF-15-1-0535, and NASA NNX15AQ03A. [Preview Abstract] |
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K1.00077: Plasmon-coupled CdSe Quantum Dots for White LEDs Quinton Rice, Sangram Raut, Rahul Chib, Zygmunt Gryczynski, Ignacy Gryczynski, Wan-Joong Kim, Sung-Soo Jung, Bagher Tabibi, Felix Seo Plasmon-exciton coupling of Au nanoparticles CdSe quantum dots (QDs) are of great interest due to the many benefits and applications in optoelectronics including wide optical tunability, high color purity, and large PL enhancement in the vicinity of plasmonic nanoparticles. Exciton recombination in CdSe QDs originates from the Coulomb interaction while quantum confinement of carriers is responsible for discrete energy states and a blue-shift from the bulk bandgap (718 nm) when the size of the QDs near the bulk exciton Bohr radius (5.8 nm). The QDs strong confinement reveals a secondary emission site which is attributed to increased surface defects due to atomic vacancies and/or incomplete crystallization during synthesis. Photoluminescence (PL) enhancement and decreased exciton lifetime was observed for the bandedge transition with 2-3 fold enhancement and the surface-trapped state transition with 1.5-2 fold enhancement which is accredited to the modified internal quantum efficiency The strong presence of the broad surface-trapped state emission combined with PL enhancement through plasmon-coupling leads to the realization of hybrid white LEDs. Acknowledgement: This work at HU is supported by NSF HRD-1137747, ARO W911NF-15-1-0535, and NASA NNX15AQ03A. [Preview Abstract] |
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