Bulletin of the American Physical Society
84th Annual Meeting of the APS Southeastern Section
Volume 62, Number 13
Thursday–Saturday, November 16–18, 2017; Milledgeville, Georgia
Session W1: Poster Session |
Hide Abstracts |
Chair: Nadia Fomin, University of Tennessee Room: Health Science 314 |
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W1.00001: Myoelectrically Controlled, 3D Printed Prosthetics Katherine Crosby, Andrew Rhodes, Eli Owens For this project, we developed a low-cost prosthetic hand using surface mounted myoelectric sensors and 3D printing. The loss of a limb can be a traumatic experience for a person, but prosthetics can restore the functionality of the limb, and confidence to the user. However, insurance often does not cover the cost of prosthetics, and entry-level prosthetics can cost over \$10,000. This motivates the need for low-cost prosthetics. We have designed and built a low-cost, highly-functional, myoelectricly controlled, 3D printed prosthetic. We use surface electrodes paired with a signal processing circuit of our design to sense healthy muscle contractions. We then use the electrical signal from the healthy muscles to naturally control the prosthetic hand. The circuit uses multiple electrodes to differentially measure independent muscle contractions. The muscle contraction signals are compared to a reference point on the elbow where little to no muscle movement is made. We use machine learning to help the controller modify the movement based on user input during a startup routine. This startup routine learns the user’s muscle habits and modifies variables in the code to make the muscular profile unique to the user. [Preview Abstract] |
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W1.00002: Mid-IR Spectroscopy of Dried Serum Samples: An Application for Colitis Prescreening Hemendra Ghimire, Kelum Perera, A. G. Unil Perera At present, colonoscopy/ileoscopy and small bowel follow through are considered as gold standard for IBD tests. Despite their unequivocal benefit for the IBD tests, compliance rates of eligible population for prescreening is very small due to discomfort, expense, and risk of complications. Developing a minimally invasive and cost-effective prescreen strategy is thus critical. We present ATR-FTIR spectroscopy of serum with appropriate data handling frameworks can be used for reliably screen experimental colitis. The study on experimental colitis models: interleukin 10 knockout mouse, and dextran sodium sulfate-induced of colitis mouse while employing collagen-induced arthritis models, TLR-5 knockout models of metabolic diseases as control, emphasizes the diagnostic potential of this technique for the prescreening. Absorbance values of the different spectral bands, hierarchical clustering and integral values of the component bands by curve fitting, show significant differences (p-value \textless 0.05) between spectra representing control and colitis mice. The preliminary result hints us the potential application of technique while diagnosing ulcerative colitis and Crohn's Disease and to monitor during treatment. [Preview Abstract] |
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W1.00003: 3D Registration in a Virtual Reality Simulator for Neurosurgical Instruction Ted Dorfeuille, Richard Rowe, Andrew Pounds Virtual Reality and computer graphics techniques have been used since their inception in numerous medical professions and it has long been thought that the technology would be ideal for training simulations. A recent review article noted that simulators for neurosurgery containing completely immersive environments and realistic touch response were particularly lacking. This project attempts to utilize commercial gaming headsets with a mechanical haptic feedback device to simulate surgery in an immersive environment with touch feedback. The focus of the current research is the use of 3D registration techniques and basis set transformations to map the space of the 3D models in the VR environment to the physical models and surgical instruments that might be in the hands of the operator. [Preview Abstract] |
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W1.00004: Thermodynamical and Biochemical Analysis of Antipyretics Used for Fever Reducing Agents Seojin Park, Richard Kyung Antipyretics are substances used in fever reducing agents. In this paper, thermodynamical and stereochemical aspects of several types of antipyretics that can be used as a fever reducing agent are studied. This research uses computational chemistry to calculate the thermodynamic stability of various fever reducing agents in order to identify whether the ingredients are of safe use for pharmaceutic products. The research uses the chemical software to find the optimized molecular geometry and calculate theoretical enthalpy of each compound models. The computer program uses DFT(Density Functional Theory) and UFF(Universal Force Field), which are used to optimize each model. The optimization configuration energy of all the molecules is collected in order to examine the relative stability of each chemical compound. It is known that the less thermodynamic enthalpy needed to stabilize the compound, the more stable the compound is. Calculations show that enthalpies of some compounds converge fast with significantly less thermodynamic enthalpy, indicating that they are relatively stable and are suitable to use as a biochemical compound in fever reducing agents. [Preview Abstract] |
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W1.00005: Molecular sensitivity and selectivity of metal nanoparticles decorated graphene as `smart' surface-enhanced Raman scattering (SERS) platforms. Sanju Gupta, A. Banaszak, T. Smith Graphene-mediated surface-enhanced Raman scattering (G-SERS) is a recent phenomenon that produces clean and reproducible Raman signals of chemical molecules with significantly enhanced intensity. Since G-SERS relies on a chemical mechanism and therefore it shows molecular sensitivity and selectivity. We developed graphene-family nanomaterials, GFNs, decorated with coinage silver and gold nanoparticles for detection of methylene blue (MB) and rhodamine 6G (Rh6G) probes in view of optical and biological importance. The results illustrate that silver and gold nanoparticles immobilized on GFNs enhanced the Raman signal, in general, and as cascaded amplification of on multilayer architecture, larger than those on the metal nanoparticles without graphene. Additionally, the sensitivity can be tuned by controlling the size of nanoparticles. Moreover, highly-sensitive graphene-nanoparticle sensors are capable of molecular detection over 10 pM to 100 microM concentration. The G-SERS enhancement is discussed in terms of graphene-metal nanoparticle interactions leading to local interfacial hybridization and polarization, 2. molecular conformation of analyte on nanoparticle-graphene functionalities, and 3. charge transfer and exchange or sharing of charges between analyte and nanoparticles decorated graphene supports, experiencing chemical enhancement. Optimized metal nanoparticle-graphene electronic properties are determined from density functional theory (DFT) calculations. [Preview Abstract] |
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W1.00006: Observation of a Stable Optical Spring Without a Cavity Benjamin Lane, Jonathan Cripe, Baylee Danz, Thomas Corbitt The current generation of gravitational wave detectors utilize high power lasers to reduce the shot noise within an interferometer. This high power creates a significant radiation pressure that couples the laser fields and the mechanical motion of the test masses opto-mechanically. This opto-mechanical coupling gives rise to an optical spring that changes the resonance of the interferometer, and thus should be studied. In this experiment, we present the observation of a stable optical spring without the use of an optical cavity. We use a Michelson-Sagnac interferometer with a GaAs microresonator as a common/end mirror. Our measurements were done using input powers of 50 mW, 100 mW, 200 mW, and 363 mW and show that the shift of the optical spring frequency as a function of input power is in excellent agreement with theoretical predictions. We also show that the optical spring can keep the interferometer stable and locked without the use of external feedback. [Preview Abstract] |
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W1.00007: High Energy Follow-up Study of Gravitational Wave Transients Brandon Barker As second-generation gravitational wave interferometers, such as Advanced Virgo and Advanced LIGO, reach their design sensitivities, a new lens into our universe will become available. Many of the most violent and energetic events in the cosmos, in particular the merger of compact objects and core collapse supernovae, are sources of gravitational waves and are also believed to be connected with Gamma Ray Bursts. Joint observations of electromagnetic and gravitational wave signals will provide an ideal opportunity to study the physics of these transient events and their progenitors. In particular, gamma ray observatories such as Fermi, coupled with precise sky localization, will be crucial to observe the high energy electromagnetic counterparts to gravitational wave signals. We constructed joint binary neutron star and gamma ray burst detection rate estimates using an analysis pipeline and report on the results of this analysis. [Preview Abstract] |
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W1.00008: Obtaining Force Uncertainties via Entropic Gravity and Generalized Uncertainty Principle Andrew Dye, Jeffery Secrest In quantum mechanics the notion of force tends to not be considered. However, utilizing various forms of the generalized uncertainty principle and the framework of entropic gravity, a force-position uncertainty relationship has been obtained. This allows for the investigation into the quantum nature of gravitational phenomena in both relativistic and non-relativistic contexts. [Preview Abstract] |
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W1.00009: Examination of Five Dimensional Bianchi Type-I FLRW Models Andrew Goetz, Jeffery Secrest Einstein's field equations for a five dimensional Bianchi type-I cosmological model were considered. The fifth dimension was a compactified dimension inserted into our model as described by Kaluza-Klein theory. Time dependent gravitational and cosmological constants were used for this model. The five dimensional universe was modeled on the equation of state of a perfect fluid, this equation of state being p = $\rho \, \omega$ where $0 \leq \omega \leq 1$. Various forms of the cosmological constant were examined. From this a variety of solutions were obtained and the physical significance of each solution was discussed. [Preview Abstract] |
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W1.00010: Highlights from the INTEGRAL Spiral Arms Monitoring Program Sean Antosiak, Quinton Dzurny, Arash Bodaghee We describe the scientific objectives and highlights from 4 years of high-cadence monitoring of the inner spiral arms of the Galaxy in X-rays (3-100 keV). The INTEGRAL Spiral Arms (ISA) program (12.8 ks per observation for a total of 1.2 Ms per year) complements the successful Galactic Bulge (GB) program by extending the monitored regions to the Inner Perseus/Norma Arm tangents on one side of the GB, and the Scutum/Sagittarius Arms on the other. These fields feature a high density of obscured high-mass X-ray binaries (HMXBs), including Supergiant Fast X-ray Transients (SFXTs), as well as other hard X-ray emitting sources (e.g. microquasars, low-mass X-ray binaries, and magnetars) that INTEGRAL is well-suited to finding thanks to its large field of view and angular resolution at high energies even in crowded regions of the sky. Mosaic images and source light curves in 2 energy bands for ISGRI and JEM-X are provided to the community at isa.gcsu.edu permitting rapid dissemination of results which enable prompt follow-up of interesting events. The ISA project represents the cornerstone of our ongoing study of transient and variable hard X-ray populations in the Milky Way. [Preview Abstract] |
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W1.00011: Photometry of High-Redshift Gravitationally Lensed Type Ia Supernovae~ Annastasia Haynie Out of more than 1100 well-identified Type Ia Supernovae, only roughly 10 of them are at z\textgreater 1.5. High redshift supernovae are hard to detect but this is made easier by taking advantage of the effects of gravitational lensing, which magnifies objects in the background field of massive galaxy clusters. Supernova Nebra (z$=$ \textasciitilde 1.8), among others, was discovered during observations taken as part of the RELICS survey, which focused on fields of view that experience strong gravitational lensing effects. SN Nebra, which sits behind galaxy cluster Abell 1763, is magnified and therefore appears closer and easier to see than with HST alone. Studying high-redshift supernovae like SN Nebra is an important step towards creating cosmological models that accurately describe the behavior of dark energy in the early Universe. Recent efforts have been focused on improving photometry and the building and fitting of preliminary light curves. [Preview Abstract] |
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W1.00012: Stability and Concurrence of an Entangled Theta State Qubit in a Reissner -Nordstrom Spacetime Keith Andrew, Benjamin Thornberry, Eric Steinfelds We consider the construction of an X state density matrix for an open Dirac system in a curved spacetime manifold with geodesic structure given by the Reissner-Nordstrom metric. Using an asymptotic Minkowski Hadamard-CNot gate configuration we construct a maximally entangled Bell state density matrix. This system is generalized using a Theta State Qubit representation and coupled to an environmental thermal background given by the cosmic microwave background distribution and located in a Reissner-Nordstrom (RN) space-time. The RN spacetime corresponds to a static spherically symmetric charged mass distribution with an outer Event Horizon and an inner Cauchy Horizon. The metric structure of the horizons is a function of the mass and charge distribution of the system. By applying a Bogoliubov transformation in Kruskal coordinates to the entangled state and a filter, which undergo a weak measurement in a region near the horizon while being exposed to the RN Hawking radiation, we can express the qubit density matrix as a function of temperature. We plot the Concurrence as functions of mass and charge to determine the parameter range that lead to the decay and eventual destruction of the entanglement of the qubit state [Preview Abstract] |
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W1.00013: Comparing the spatial distributions of HMXBs and star-forming regions in the Small Magellanic Cloud Ryan Agnew, Quinton Dzurny, Arash Bodaghee The Small Magellanic Cloud (SMC) is a satellite galaxy of the Milky Way. Thanks to its relative proximity, 234 massive stellar clusters are easily resolved with modern telescopes as are 72 byproducts of these nurseries: so-called high-mass X-ray binaries (HMXBs) which are systems comprising a massive star paired with a collapsed star such as a neutron star or black hole. However, a direct link between an HMXB and its parent cluster is not immediately clear except in rare cases. The purpose of this study is to determine the proximity of these two related populations by performing a statistical analysis of their spatial distributions as observed in the SMC. Our study represents the first ever application of the two-point correlation function to the populations of another galaxy. A significant correlation has been found, and these results provide clues to the evolution of massive stars such as the magnitude of the natal kick received by the HMXB during the supernova, and the time that elapses between the supernova and accretion phases of the HMXB. [Preview Abstract] |
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W1.00014: An Atmospheric Column Model Coupled to Surface Adsorption for Martian Methane Production in Gale Crater Using JSC-1 Martian Simulant with Metallic Sulfates Keith Andrew, Eric Steinfelds, Kristopher Andrew, Melinda Thomas, Alicia Pesterfield, Quentin Lineberry We consider an atmospheric column model with solar UV forcing and competitive Langmuir, Freundlich, and BET adsorption based reactions at the atmosphere-surface interface to investigate methanogenesis on Mars. By combining Curiosity rover data, with the Mars Climate Database 5.2 and lab measurements of JSC-1 Martian Regolith Simulant we model the near surface adsorption reaction pathways linked to methane production. The effects of freezing point depression from metallic hydrated sulfates and a Clausius-Clapeyron mixed state phase give rise to subsurface liquid interactions that add to the Bloom model of deliquescence and biogenetic sources for methane. We numerically solve an integro-differential equation for methane production that can be cast as a Volterra Equation Column Model yielding subsurface production of methane that is moderated by the local daily and seasonal variations of solar radiation. We find that there are reasonable values for the geochemical reaction rates as functions of local temperature, solar radiation, humidity, partial pressure, and soil granularity to produce methane levels that compete with biogenic extremophile based sources. [Preview Abstract] |
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W1.00015: Pre-Merger History of Illustris-Simulated Galaxy Pairs Alice Jacques, Spencer Shortt, Kiernan Reising, Donovan Domingue In this work, we analyze the history of 24 simulated major-merger galaxies including star formation and mass growth with emphasis on morphological type dependencies. Pairs were identified as major-merger galaxy candidates (mass ratio \textless 2.5) within the Illustris simulation; with the goal of comparing them to observations of SDSS-2MASS selected galaxy pairs and visually classifying their morphology. Approximately 7000 total galaxies fit within our mass range with 356 candidate pairs reduced by separation, mass, and relative velocity criteria to a final sample of 24 simulated physical pairs at various stages of pre-merger galaxy interaction. Illustris masses and star formation are presented across the simulation snapshots in an effort to understand the pre-paired history of observationally selected analogs. [Preview Abstract] |
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W1.00016: Constraining Extinction due to Dust in Distant Galaxies Alexander Kirby, Varsha Kulkarni Extinction due to interstellar dust is a ubiquitous phenomenon that dims and reddens the light of background objects. As such, it is essential to apply extinction corrections to observations of distant objects in order to deduce their properties. Since the discovery of interstellar extinction in 1930, astronomers have developed a fairly detailed understanding of the interstellar dust in the Milky Way and other Local Group galaxies, especially the Magellanic Clouds. However, studies of extinction by dust in galaxies beyond the Local Group have been limited. In this work, we seek to generate better constraints on dust extinction in other galaxies in order to improve corrections for observations of objects that lie beyond them. As such, we are constructing spectral energy distributions (SEDs) for quasars/active galactic nuclei whose lines of sight go through foreground galaxies at lower redshifts. We will describe our compilation of archival optical, UV, and IR spectroscopic and photometric data from various observatories. Using the SEDs compiled from these data, and fitting the underlying continuum of the background quasar/AGN, we will estimate dust extinction curves for each foreground galaxy, and compare those with extinction curves in the Milky Way and the Magellanic Clouds. [Preview Abstract] |
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W1.00017: Fermi-LAT daily monitoring observations of the microquasar Cygnus X-1 Stephen Hood, Austin Waldron, Arash Bodaghee A microquasar is an accreting compact object (such as a neutron star or a black hole) with relativistic jets. These are much smaller versions of quasars which are supermassive black holes occupying the centers of large galaxies. Their smaller size enables them to vary on short timescales of hours to days, compared with months to years for quasars. Therefore, microquasars are important tools for studying the physics of matter in extreme electromagnetic and gravitational fields. While they are expected to emit across the electromagnetic spectrum, only a handful of microquasars have ever been detected in gamma-rays and these detections are rare and short-lived. In this study, we analyzed over eight years of gamma-ray observations of a well-known microquasar called Cygnus X-1 as gathered by the Fermi space telescope. Our study continues the daily monitoring previously introduced in Bodaghee et al. (2013) with new data extending from 2012 to 2016. The purpose of the study is to confirm previous gamma-ray outbursts of Cygnus X-1, and to detect new candidate outbursts (a dozen of which were found). Detection of gamma-ray emission from microquasars is important for understanding particle acceleration in the jet, and for constraining leptonic/hadronic emission models. [Preview Abstract] |
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W1.00018: Determining the 3D Orientation of High Velocity Clouds by Monte Carlo Modeling Kristy Sakano The star formation history of the Galaxy suggests continual gas accretion. Some of this star formation fuel appears in the form of high velocity clouds (HVCs). The origin of HVCs is still debated. One crucial ingredient in this puzzle is the generally unavailable trajectory information. Yet, many of the compact HVCs show clear signs of interaction with the background halo medium. We present a method to determine the 3D velocity vector of compact HVCs. The method is based on a HVC's morphology and kinematics. We calibrate the method using analytical and numerical model HVCs. We present an efficient algorithm to determine the 3D orientation of observed compact HVCs. With this method, Galactic halo gas dynamics as traced by compact HVCs can be mapped. [Preview Abstract] |
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W1.00019: Applications of Neutrosophic Quadruple Algebraic Structures Florentin Smarandache, A. A. A. Agboola, B. Davvaz A Neutrosophic Quadruple Number is a number of the form: NQ $=$ a$+$bT$+$cI$+$dF, where a, b, c, d are real or complex numbers, while T $=$ truth, I $=$ indeterminacy, and F $=$ falsehood. For each NQ, a is called the determinate part of NQ, while bT$+$cI$+$dE the indeterminate part of NQ. A Preference Law, with respect to T, I, F, we may define on the set of neutrosophic quadruple numbers. For example, let's say T \textless I \textless F. With respect to this preference law, we define the Absorbance Law for the multiplications of T, I, and F, in the sense that the bigger one absorbs the smaller one (or the big fish eats the small fish); for example: TT $=$ T (T absorbs itself), TI $=$ I (because I is bigger), FT $=$ F (because F is bigger), and so on. The addition and subtraction of neutrosophic quadruple numbers are defined as: (a$_{\mathrm{1}}+$b$_{\mathrm{1}}$T$+$c$_{\mathrm{1}}$I$+$d$_{\mathrm{1}}$F) $+$ (a$_{\mathrm{2}}+$b$_{\mathrm{2}}$T$+$c$_{\mathrm{2}}$I$+$d$_{\mathrm{2}}$F) $=$ (a$_{\mathrm{1}}+$a$_{\mathrm{2}}) \quad +$ (b$_{\mathrm{1}}+$b$_{\mathrm{2}})$T$+$(c$_{\mathrm{1}}+$c$_{\mathrm{2)}}$I$+$(d$_{\mathrm{1}}+$d$_{\mathrm{2}})$F; (a$_{\mathrm{1}}+$b$_{\mathrm{1}}$T$+$c$_{\mathrm{1}}$I$+$d$_{\mathrm{1}}$F) - (a$_{\mathrm{2}}+$b$_{\mathrm{2}}$T$+$c$_{\mathrm{2}}$I$+$d$_{\mathrm{2}}$F) $=$ (a$_{\mathrm{1}}$-a$_{\mathrm{2}}) \quad +$ (b$_{\mathrm{1}}$-b$_{\mathrm{2}})$T$+$(c$_{\mathrm{1}}$-c$_{\mathrm{2)}}$I$+$(d$_{\mathrm{1}}$-d$_{\mathrm{2}})$F. While multiplication (a$_{\mathrm{1}}+$b$_{\mathrm{1}}$T$+$c$_{\mathrm{1}}$I$+$d$_{\mathrm{1}}$F)(a$_{\mathrm{2}}+$b$_{\mathrm{2}}$T$+$c$_{\mathrm{2}}$I$+$d$_{\mathrm{2}}$F) is defined as in classical multiplication of polynomials, but taking into consideration the above absorbance law when multiplying the T, I, F among themselves. Various neutrosophic quadruple algebraic structures and their applications are studied on the set of NQs. [Preview Abstract] |
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W1.00020: Linear Dependencies in Friction Stir Welding Conditions Jeremiah P Simmons, William R Longhurst Friction stir welding is a solid-state process that joins materials using heat generation to soften the material to a state of plasticization, and mechanically inter-mixing the materials. The process generates a lower threshold of heat across the weld, therefore attaining a stronger weld through plasticizing rather than melting the materials together. In this study we observed conditions during the welding process including: position, heat distribution, current input, and torque across the tool-bit. Three specific revolutions per minute (rpm) of the tool-bit were observed: 1400, 1600, and 1800 rpm. Linear relationships were identified and analyzed between torque and current input, as well as heat distribution and current input. Post-weld analysis revealed linear slopes as small as -.0135 Amps per Newton meters across the duration of the weld for torque-current relationships, and as small as .0014 Amps per degree Celsius for the duration of the weld for heat-current relationships. These linear strategies could be effective control methods for future welds to procedurally detect the creation of weld defects. [Preview Abstract] |
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W1.00021: Plasma Characterization in Magnetron Sputtering Spencer Lovelady, Kendal McDonald Magnetron sputtering is a technique used for semiconductor thin film deposition. A plasma is generated during the sputtering process. Study of the plasma is important in order to understand the deposition process and to have a better reproducibility of thin film deposition. We used optical emission spectroscopy as the primary plasma diagnostic tool. Ocean Optics HR 4000 high resolution spectrometer was used within the wavelength range of 200 nm to 1100 nm. The intensity ratio of Argon 750 nm and Argon 751 nm lines were further investigated to determine the effects of different deposition parameters such as deposition pressure and deposition power. Trends in the excitation temperature corresponding to the deposition power and deposition pressure will also be discussed. [Preview Abstract] |
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W1.00022: The Development of a Retina Controlled Prosthetic Device for Human Augmentation Brian Skoglind, Jacob Brewer, Hauke Busch We are using LabVIEW to design and build a retina controlled prosthetic limb that can be used to help augment individuals with disability. Due to the recent wars, there has been an increase in injured veterans returning with the need of a prosthetic limb. Traditionally, prosthetic limbs have been passive devices; our design would make it an active device. The immediate objective of this research project is to understand the capabilities of LabVIEW and construct an original artificial limb. Currently we are in the process of 3D printing a prosthetic hand and testing different materials to find a material strong yet flexible enough to act as joints. We are also working on taking visual input from the camera into LabView. The prototype will be controlled through Virtual Instruments (VIs) and a National Instruments device called, MyRIO. Other applications of this research can be implemented into wheel chair operations with individuals with more severe disabilities. [Preview Abstract] |
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W1.00023: Supercavitation Capabilities On a Submarine Zachary Galberd, Joseph Cummings, Luke Walsh, Kenneth Adamas, Hani Alsharif, Hauke Busch Throughout history submarines have shaped the way wars have been fought and changed our understanding of fluid dynamics. In the past, an idea has been used to increase the velocity of torpedoes in Chinese and Russian Submarines, called supercavitation. An example of this is the Russian VA-111~\textit{Shkval} torpedo. The idea being that if your submarine is traveling at a certain velocity underwater, and you are expelling a gas out of the nose cone region, thus creating a boundary layer, you will be ``flying'' in that new medium. This allows a torpedo to travel at faster speeds making any evasive actions of the targeted submarine or surface vessel extremely difficult. The purpose of our project is to explore the benefits and limitations of supercavitation. This information will then be implemented into a submarine to hopefully decrease its drag and increase its speed and efficiency. The obstacles we are facing include, finding ways to effectively create a boundary layer in the nose cone region suitable for submarine designs to travel through water. We are currently creating a rail and arm system to test different nose cone sections for use in a drag water tank. [Preview Abstract] |
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W1.00024: Electrical and Optical Properties of Sputtered Aluminum-doped Zinc Oxide Daniel Sexton Transparent conducting oxides (TCO) are used in opto-electronic devices. This study investigates properties of Aluminum doped Zinc Oxide (AZO) as a possible TCO candidate for solar cells. AZO thin films were deposited using RF magnetron sputtering in the presence of argon and oxygen. The properties of AZO films deposited under different deposition parameters including pressure, power and temperature were characterized using UV/Vis spectroscopy, Hall-Effect measurement and four point probe measurements. Further, optical emission spectroscopy was used to correlate the properties of the deposited thin films to the behavior of the plasma during sputtering. Trends in transmittance, mobility, band gap, resistivity, and carrier density under different deposition parameters will be presented along with the correlation of these properties to the plasma behavior. [Preview Abstract] |
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W1.00025: The Real Valued J$\alpha$m Derivative S. Kyle Castleberry, Bennet Haller, Sharon Careccia, Ralph H France III In continuation of the work presented by Pearson et al. at SESAPS 2016, we have made progress on the J$\alpha$m Derivative. Previously, we had used Wolfram Alpha to graphically analyze the derivative, but its results were incomplete. The natural logarithm of complex numbers, which occur twice in the calculations of the J$\alpha$m derivative are multivalued, with Wolfram Alpha choosing one particular value. We will present a more general case and show that a particular choice of values for these logarithms produces completely real results. [Preview Abstract] |
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W1.00026: Assessment of the Biocompatibility of the Iron Oxide Nanoparticles Treating Cancer Disease Using Computational Simulation Joo Hee Lee, Richard Kyung Bio-metals such as copper, zinc, iron, and manganese have been widely used as prominent materials for medical applications including clinical treatment such as treating cancer disease. In the past, iodine and transitional metal oxides have been used in nanoparticles for cancer detection but some of them showed harmful effects to the body. In this research, the efficiencies of magnetic nanoparticles such as iron oxide compounds used the detection of the CTC (Circulating Tumor Cells) are modeled using computer software and explained through the compound’s electron structure. Gamess is a program that allows performing such computations for a compound. It takes an input file of a defined format and converts it into an output describing the molecule and the reaction. Chemcraft and Avogadro are another programs that take the output from Gamess and expresses it as a model. These programs show the optimized geometry energy levels and they fully determines the theoretical values of the structure’s atomic properties. These computational programs were used to complement each other to produce a result that is useful to see the outcomes. [Preview Abstract] |
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W1.00027: Mechanical and Stability Analysis of Hand Truck Using Physical and Numerical Calculations Daniel Lee, Richard Kyung As an alternative to a traditional forklift or tailgate loader, the hand truck serves as a quick and easy solution for lifting, carrying, and loading small materials as well as goods, using the principle of the lever to multiply forces. Today's forklifts and hand trucks are lighter and easier to use. They also include features such as automatic uploading and brake devices. However, there are still many ways to improve hand trucks and make them more comfortable and efficient. Present research includes mechanical and stability analysis of the hand truck. To ensure structural stability and to figure out whether the internal forces in the materials are tensile or compressive, our research focused on setting up equilibrium equations and calculating the forces on each links and members of the hand truck. In addition, we presented an analytical method to determine the static forward, rear, and lateral stability of the hand truck on a tilting platform. The weight and dimension of the goods, along with the location of the center of gravity, were shown as the factors affecting the stability. The objective of the second part of the presented research was to determine the extent of the effect of load positions on the hand truck stability. [Preview Abstract] |
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W1.00028: Bio-fluid Analysis in the Microfluidic Channels in the Organ-On-a-Chip Systems. Jaehyuk Lim, Richard Kyung Organ-on-a-chip (OOC) systems are microfluidic 3D models of human tissue and organs. This system allows stimulation of various biological and physiological mechanisms of the human body. The organ-on-a-chip system has displayed a strong potential for use in personalized medicine and drug screening. Such a breakthrough can substitute traditional methods such as the conventional planar and static cell cultures, and therefore, reduce the use of animal models. The organ-on-a-chip replicates the function of the organ on a smaller scale, which not only reduces time and cost invested into experiments, but also produces better results. The organ-on-a-chip system is a valuable tool in further studying the functional properties, pathological states, and development of organs. This OOC system displays a laminar flow scheme. The laminar scheme has slow flow rate and higher fluid viscosity, resulting in a small Reynolds number. This paper assumes the laminar flow scheme from the small dimensions of the microfluidic cell culture chip. This study examines the flow of the microfluidic channels in the OOC systems, and the consequences of altering pressure and velocity in these channels. [Preview Abstract] |
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W1.00029: Sound Speed and Chromatic Scales in Granular Materials Sydney Blue, Eli Owens Granular materials are collections of athermal, macroscopic particles that behave unlike other more traditional materials. In particular, sound propagation through granular materials is not well understood. For this study, we send sound through a uniform, granular material composed of airsoft BB's. We then measure how the sound travels through the granular material with buried piezoelectric sensors. One important feature of a granular material is its sound speed; which we measure by sending a pulse of sound through the granular material and recording the time delay between two piezoelectric sensors separated by 10 cm. We are then able to measure the time of flight and the sound speed. We repeat these sound speed measurements for different particle configuration and find that the distribution of sound speeds is consistent with prior measurements of interparticle force, confirming that the speed of sound scales with interparticle force. Additionally, we investigate the material's response as we move through the musical chromatic scale. This work will lead to a better understanding of granular acoustics supporting the development of technology that utilizes granular acoustics for tasks such as non-destructive testing and probing of granular materials. [Preview Abstract] |
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W1.00030: The Effect of Grain Shape on Confined Granular Flows Salem Wright, Ellen D'Amico, Eli Owens Granular materials are collections of macroscopic particles, such as corn, rice, and peas. Grain silos store granular particles and are subjected to irregular force build-up, which can have catastrophic results. It has long been observed that the pressure at the bottom of a silo is screened as the silo is filled. We studied the force build-up on the side-walls of grain silos from materials of different aspect ratios, specifically corn, peas, and rice. The model silo used in the experiment was constructed out of sheet metal pipe 120 cm in length and 15 cm in diameter held in place by a frame constructed of 80/20 aluminum. Four force sensors were evenly spaced vertically at the bottom of the silo and used disks of sheet metal approximately 2.5 cm in diameter screwed into the sensors’ internal load cells to evenly distribute the applied force. The fill height was approximately 100 cm from the bottom of the silo. Our work found that rice exhibited more irregular force build-up than peas and corn. This work will allow us to better understand the behavior of confined granular flows with respect to grain shape and will provide insight into design methods for grain silos, as well as assist with understanding grain shape’s effect on natural phenomena like avalanches. [Preview Abstract] |
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W1.00031: Percolation Threshold from a Giant Subgraph of a Twitter Based Nodal Graph Keith Andrew, Morgan Taylor, Phillip Womble, Karla Andrew, Kay Opalenik, Craig Cobane We find the critical edge value p which almost surely determines the percolation threshold for a minimal giant subgraph of a host graph G, using the Lu Subgraph Percolation Theorem for a Twitter based social media graph. We determine the linear time dependence of the exponent of the degree distribution function for the resulting giant subgraph. This time rate of change is compared to the rate of change for the corresponding centrality eigenvalues within the Giant Subgraph and to external edges that connect to nearby clusters. The greatest rates of change are coupled to the Parts of Speech (POS) Indicators for selected memes with topic specific verb and adjective bigrams. The differences between these values and the Percolation Centrality are used as indicators of graph activity and are modeled to generate a global graph entropy used to capture the large scale connected complexity of the graph. We explicitly calculate these values for the Twitter activity related to the example of information tweeted from topics on Banned Books for the Handmaids Tale and government focused cluster subgraphs in a Tweet-Retweet graph. [Preview Abstract] |
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W1.00032: Efficient Coupling of Acoustic Power into Granular Materials Brandon Morrow, Eli Owens Granular materials are made up of a collection of distinct, macroscopic particles such as a pile of sand. When these particles are packed together, they create a heterogeneous distribution of forces inside the granular material. This heterogeneous force distribution is not very well understood, and contributes to non-linear, highly dissipative, sound propagation. In order to maximally couple sound into a granular material, we seek a coupling device to impedance match with the granular material. An example of a coupling device that works in air is the cone on a speaker. Current methods of probing granular materials involve sending high energy waves, where most of the energy is lost through dissipation. Finding a coupling device would allow deeper non-destructive probing at lower energy than currently available. To analyze the effects of each coupling device on the acoustic power, we buried piezoelectric sensors in sand to determine the amplitude directly below, and at an angle from the source. During our measurements, we swept the frequencies from 10Hz-10kHz in order to observe the effect of the coupling device on the amplitude at different frequencies within our system. This allowed us to find a coupling device that produces the highest amplitude for the lowest driving energy. [Preview Abstract] |
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W1.00033: Design of the FIU Ion Propulsion Engine (FIPE) Stephen Revsez Long duration space flights will at some point require an efficient engine to withstand the depths of space and time. Chemical rockets are the power house engines used to bring payloads into low-Earth orbit (LEO), maneuver satellites, and among other tasks. Another type of engine utilizes the electromagnetic forces of charged particles to create thrust instead of controlled explosions. These engines are dubbed ion or hall-effect thrusters. Both differ in their techniques for accelerating charged propellant gas by either using charged grids or orthogonal magnetic fields to confine particles as a pseudo-grid near the exhaust. For this research we focused on the ion or gridded acceleration method and set out on designing a thruster that utilizes easy construction and dismemberment in outer space. An important part of this research was on the materials that were to be used for constructing a model of the engine for experimentation and examination of its efficiency. The design is also described in detail by CAD drawings of the final design of the engine. The engine is the first to be designed and eventually built at Florida International University and thus is named the FIU Ion Propulsion Engine (FIPE). [Preview Abstract] |
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W1.00034: The role of the dynamic plasmapause in outer radiation belt electron flux enhancement and three-belt structure formation Margie Bruff, Allison Jaynes, Hong Zhao Plasma waves inside and outside the Earth's plasmasphere can lead to loss or acceleration of high energy outer radiation belt electrons. Early studies found an apparent correlation on long time scales between the observed inner edge of the outer radiation belt and the simulated innermost plasmapause location. Recent work using high resolution satellite data has revealed a more complex relationship. The aim of this project was to provide a systematic study of the dynamics of the plasmapause compared to the outer belt MeV electrons. We used REPT electron flux and EFW derived density data from the Van Allen Probes. We found that the location of peak flux was consistently outside the innermost location of the plasmapause at enhancement times, with an average standoff distance $\Delta $L$=$1.0 $+$/- 0.5. This is consistent with current chorus enhancement models and previous chorus wave observations. We also identified ``three-belt'' structure events where a second outer belt formed. We found a repeated pattern of plasmapause dynamics associated with specific changes in electron flux required to generate and sustain these structures. This study is significant toward understanding how the plasmasphere under differing conditions can shield Earth from or worsen the impacts of geomagnetic activity. [Preview Abstract] |
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W1.00035: Polarimeter Construction for Measurement of Polarization in GRBs Roark Habegger, Dan Reichart The purpose of this project is to construct an autonomous polarimeter and attach it to an also autonomous telescope at Cerro Tololo Inter-American Observatory in the Chilean Andes. The polarimeter consists of two half-wave plates and two beam-splitting cubes, one for each of V and I band polarimetry. Eight pictures (four polarization angles times two cameras) are acquired and processed for each polarization measurement. Once integrated with the telescope, the instrument will automatically slew to Gamma-Ray Bursts (GRBs) localized by NASA's Swift spacecraft, and make polarization measurements in both bands. This will allow us to confirm that GRBs are driven by strong, and highly ordered, magnetic fields in their first few minutes. [Preview Abstract] |
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W1.00036: Examining Harmonic Motion in TeachSpin’s Torsional Oscillator (TO1-A) April Garrity, Alexander Joyce, Sethfield Smith TeachSpin’s Torsional Oscillator (TO1-A) was used to conduct a variety of experiments related to harmonic motion. Various aspects of this were investigated, including the phase relationship between angular position and angular velocity, the dependence of the period of oscillation on the moment of inertia by adding brass quadrants, and the independence of tension on period of oscillation by adjusting the torsion constant of the wire. This device can be used for further experiments including magnetic torque, damping, and driven oscillations. [Preview Abstract] |
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W1.00037: Subjective Dilation-Time Florentin Smarandache For two observers, in two moving referential frames at different speeds, each one sees a time dilation different from the other time dilation (or time-dilation symmetry). But these are clearly subjective time dilations, not an objective time dilation. These symmetric time dilations cannot be simultaneously done in practice; it is absurd. The proponents of the Theory of Relativity assert that the so-called black hole is so powerful, that even the time itself is brought to a stop. But this looks very much as science fiction, since the objective time goes on anyway. [Preview Abstract] |
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W1.00038: Laser Interferometry and Precision Measurements Nicholas Tomlinson, Arden Lesley, Michael Doucette, Dr. R. S. Smith A basic Michelson Interferometer was built using a 633 nanometer Helium-Neon Laser along with mirrors, a beamsplitter and a photodiode detector placed on the optical breadboard of a Newtonian Labs Laser Interferometry apparatus. One of the mirrors contains a Piezoelectric Transducer that is used to move the mirror with an applied voltage. Electronic signals output from the apparatus were analyzed using a Tektronix TBS 1052B 50 MHz 1GS/s Dual Channel Digital Oscilloscope. Various methods were utilized to determine the minimum displacement that the interferometer could measure. Results on the order of a picometer were obtained. [Preview Abstract] |
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W1.00039: Below Threshold Dielectronic Recombination for B$^{2+}$ and C$^{2+}$ A. B. Nemer, S. D. Loch, M. S. Pindzola Below threshold dielectronic recombination is investigated for e + B$^{2+}(1s^2 2s)$ -> B$^+(1s^2 2p 3d)$ and for e + C$^{2+}(1s^2 2s^2)$ -> C$^+(1s^2 2s 2p 3d)$. Relativistic atomic structure (GRASP) calculations are used to calculate energies and wavefunctions. Relativistic distorted-wave (AUTOSTRUCTURE) calculations are used to calculate radiative and autoionization rates. The dielectronic recombination rate coefficients were then used to make a synthetic spectrum for use in plasma diagnostics. Photoionized cold plasma temperature and abundance diagnostics are chiefly important for astrophysical applications that currently suffer from vast discrepancies. [Preview Abstract] |
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W1.00040: Double Ionization of He using UV and IR Laser Pulses M. S. Pindzola, G. M. Laurent, J. P. Colgan A time-dependent close-coupling method is used to calculate the multiphoton double ionization of He using a combination of UV and IR laser pulses. Momentum space wavefunction densities, as well as single and triple differential probabilities, calculated for the two and three photon double ionization of He using a UV laser pulse are compared with those in the presence of an additional IR laser pulse. [Preview Abstract] |
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W1.00041: Electron Impact Single and Double Ionization along the Fe Isonuclear Sequence S. D. Loch, M. S. Pindzola Electron-impact single and double ionization cross sections for Fe, Fe+, Fe+2, Fe+3, and Fe+4 are calculated using a combination of perturbative distorted-wave and non-perturbative time-dependent close-coupling methods. The single ionization cross section includes contributions from outer subshell direct ionization and excitation-autoionization. The double ionization cross section includes contributions from direct double ionization as well as from inner subshell direct ionization and excitation-autoionization. The cross sections for single and double ionization are compared with crossed-beams measurements. [Preview Abstract] |
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W1.00042: Using an Atomic Molecular Optics Laboratory for Undergraduate Research and Mentoring of Physics Students in Georgia Matthew Dallas, Hauke Busch An Atomic and Molecular Optical (AMO) Physics research lab is an excellent tool to train and mentor undergraduate students in advanced laboratory techniques. Students gain valuable basic experience in experimental designs, data acquisition techniques, working with high precision optical equipment, building electronics, and working in the machine shop. The current project is building and testing an enclosure for the diode laser to reduce sound and vibrational interference. In addition, we are developing and evaluating a new, more compact laser cavity which is 3D printed. Previously completed projects involved building a temperature controller, current supply circuit, machining the laser mount, milling the vacuum chamber mounts to support the chamber, and machining the Helmholtz coils for the chamber, which are being used to trap the atoms in a Magneto Optical Trap (MOT). This included designing, building, and baking out the vacuum chamber, constructing a trap for the Rb in the chamber, and building the lasers for a saturation-absorption system that is used to probe the 5$^{\mathrm{2}}$S$_{\mathrm{1/2}}\to $ 5$^{\mathrm{2}}$P$_{\mathrm{3/2}}$ hyperfine energy transitions of the Rb-85 atom. These energy transitions have been used to frequency-lock a diode laser to trap Rb-85 atoms and then cool them to ultra-low temperatures. The atom cooling will permit observation and measurement of the fundamental properties of atoms. This lab has mentored and supported over twelve undergraduate students in the last seven years, resulting in students becoming HS Teachers, and joining Ph.D. and engineering programs. [Preview Abstract] |
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W1.00043: Magnetic field structure in laser photodetachment to the first excited state of the O atom Joseph Martin, Hannah Thigpen, John Yukich Photodetachment spectroscopy for ions such as S$^{\mathrm{-}}$ and O$^{\mathrm{-}}$ has been examined in previous experiments for detachment to the ground state of the neutral atom. In many of these experiments, structure in the cross section due to Zeeman and cyclotron transitions has been resolved. Our current experiment examines a transition to the first excited state of the O neutral in an attempt to detect similar cyclotron and Zeeman structure. The apparatus in the experiment includes a Penning ion trap which creates, traps and stores the O$^{\mathrm{-}}$ ions, and a single-mode, tunable, amplified diode laser. Although the overall transition is much weaker than transitions to the ground state of the neutral, we have observed cyclotron structure in detachment to the $^{\mathrm{3}}$P$_{\mathrm{1\thinspace }}$excited state. It is anticipated that analysis of the data will yield a measurement of the $^{\mathrm{2}}$P$_{\mathrm{1/2\thinspace }}\to $ $^{\mathrm{3}}$P$_{\mathrm{1\thinspace }}$electronic transition energy. [Preview Abstract] |
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W1.00044: Spatiotemporal Properties of Solid State Harmonics Christopher Abadie, Mengxi Wu, Mette Gaarde As shown by recent experiments, high-order harmonics can be generated in a transparent crystal by a high intensity infrared laser beam. We investigate the spatial and temporal properties of such harmonics by calculating the harmonic spectrum at many different points in space spanning the laser focus and then transforming to the far field. Each harmonic spectrum is calculated by solving the time-dependent Schrödinger equation for an electron in a periodic potential to find the laser-driven electron current that gives rise to the harmonic radiation. We find two distinct contributions to the harmonic radiation in the far-field distribution, and by using a spatial filter we isolate the central contribution. After performing a back-transformation to the near-field, we find that the filtered integrated spectrum is much cleaner than the original as it shows stronger peaks at odd harmonics. We find that the spatial filter also works as a temporal filter, so that the sub-cycle harmonic time profile after filtering is dominated by one burst of light per half-cycle of the laser field. Our results suggest that many of the techniques used to control the spatiotemporal properties of high order harmonics from gases can also be applied to harmonics from solids. [Preview Abstract] |
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W1.00045: A novel algorithm for Velocity Map Imaging systems Geoffrey Harrison, John Vaughan, Brock Hidle, Guillaume Marc Laurent In this work, we report a novel algorithm to reconstruct the three-dimensional (3D) momentum space picture of any charged particles collected with a Velocity Map Imaging system from the two-dimensional (2D) projected image captured by a detector \footnote{B. J. Whitaker, Imaging in Molecular Dynamics: Technology and Applications (Cambrigde University Press, Cambridge, 2003).}. The method uses the proper analytical two-dimensional projection function to retrieve the 3D distribution. The meaningful angle-correlated information is first extracted from the raw data by expanding the 2D image with a complete set of Legendre polynomials. Both the particle's angular and energy distributions are then retrieved from the expansion coefficients. The algorithm is simple, easy to implant, fast, and does not require any initial guess for the 3D distribution. In addition, our procedure explicitly takes into account the pixelization effect in the measurement \footnote{G. Harrison, J. Vaughan, B. Hidle, and G. M. Laurent, A simple algorithm for Velocity Map Imaging system, submitted}. [Preview Abstract] |
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W1.00046: Microprocessor-based control system for cooling and trapping $^{\mathrm{6}}$Li atoms Levi Salyards, Jonathan Jeffrey, Andrew S. Blount, Yun Long, Colin Parker We present an electronic control system for laser cooling and trapping experiments. The system is responsible for all signal generation and timing used to generate a magneto-optical trap (MOT) of $^{\mathrm{6}}$Li, and for subsequent optical trapping and imaging. Our system is capable of driving acousto-optical modulators (AOMs), controlling magnetic fields, stabilizing laser intensities, and operating cameras, all of which are synchronized to a sub-microsecond interval. This improves upon other systems by incorporating a feedback element to the AOM (which allows laser intensity stabilization), by centralizing control to one computer, and by allowing simultaneous adjustment of all devices in the control system. Having a centralized control system permits us to both image the atomic trap and manage any beam from a single computer. Our control system is realized by pairing a microprocessor with each electronic device, allowing the user to tune system parameters quickly and efficiently. Communicating with the microprocessors is a two-step process. We first use TCP/IP communications to transmit to an Ethernet-capable microprocessor, which then uses serial UART communications to disseminate commands to the individual devices. Finally, we have developed a user interface that streamlines the process of controlling an experiment and removes the need for users to program a sequence. [Preview Abstract] |
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W1.00047: The Hyperfine Structure of Rubidium Fabiola Diaz, Charles Harrill, Mary Mulholland, Dr. R. Sethfield Smith An external cavity diode laser (ECDL) was used to provide a very narrow range of laser wavelengths near 780 nm in order to study the structure of rubidium (Rb). The absorption spectrum of Rb was measured. This spectrum was subject to Doppler-broadening of the spectral lines. A technique known as Saturated Absorption Spectroscopy was employed to eliminate the effects of Doppler-broadening and to obtain a high resolution spectrum for Rubidium. The setup, operation, and performance of this system will be described. [Preview Abstract] |
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W1.00048: Plasmon tuning via the conductivity tensor Morgan LaBalle, Maxim Durach Metallic structures with corrugated surfaces have applications in a variety of research areas. As these structures are very important, it is essential that their properties be well understood. However, the solutions to Maxwell's Equations in corrugated structures are difficult to determine. Thus, an alternative, simpler approach to solving this structure would be very advantageous. We have developed such an approach by modeling the corrugated surface as a thin film with an optical conductivity. When light is incident upon a metal-air interface, the electromagnetic fields are able to form a surface plasmon wave that possesses a shorter wavelength than light in free space. Our model's boundary conditions allow us to describe the k-vector of the wave with the film's optical conductivity. After a thorough investigation of the dependence of the k-vector on this conductivity, we have determined that the k-vector can take values greater than or equal to zero. Those values correspond to various tuned plasmon waves. By matching one of these waves with those produced in experiments, we are able to more fully investigate the properties of corrugated metal-dielectric interfaces. [Preview Abstract] |
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W1.00049: Solar Spectral Irradiance and Surface Ozone Changes at Carrollton, Georgia during the Great American Eclipse on August 21, 2017 Charles Zander, K. Tennakone, Ajith DeSilva, Shea Rose, Austin Kerlin Measurements of solar spectral irradiance and surface ozone at the University of West Georgia, Carrollton, during the Great American eclipse on August 21$^{\mathrm{st}}$, 2017, indicated changes in spectral irradiance and ozone surface concentration. The integrated spectral irradiance in defined wavelength ranges in the ultraviolet (300 -- 390 nm) and visible (391 -- 700 nm) reached a minimum at the maximum obscuration (\textasciitilde 95{\%}) of the sun, whereas in an infrared range (701 -- 1040 nm) reached a maximum. The method of analysis of observational data vividly displayed this effect originating mainly due to limb darkening. In the surface ozone measurement, a minimum in ozone concentration occurred thirty minutes after the instant of maximum obscuration. The observation is explained as a result of the kinetics of photo-chemical creation of ozone and its photo-chemical and non-photochemical degradation. [Preview Abstract] |
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W1.00050: Analytic Solution to a Three-Level Optical Pumping System with Constant Coefficients William Dulaney, Tyler Dula, Julia Hinds In the process of developing a new senior-level laboratory experience in atomic phosphorescence, a lack of consistency has been noted in the literature for the room-temperature radiative lifetime associated with the emission of the R-lines of Cr$^{\mathrm{\thinspace 3+}}$ in ruby. Much of the existing work on the metastable$^{\mathrm{\thinspace 2}}$E term that gives rise to the R-lines focuses on the fluorescence decay of these lines. Here the excitation of the metastable population as a function of time is investigated to supplement an understanding of these radiative transitions. In an attempt to identify an appropriate parent population for the metastable terms during the excitation phase, the dynamical system is approximated as three-energy levels in Cr$^{\mathrm{\thinspace 3+}}$ in ruby: a ground state, a ``pump'' excited state, and a metastable state. Assuming a constant optical pumping rate and natural decay rates for the pump and metastable energy levels, three coupled first-order, linear, differential equations have been deduced for the observed population dynamics for the three states in response to optical excitation. The analytical and numerical solutions of these equations are presented here with preliminary comparisons to experimental data for the radiative excitation and de-excitation of the metastable levels in Cr$^{\mathrm{\thinspace 3+}}$ in Ruby. [Preview Abstract] |
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W1.00051: Absolute cross section measurements using relative pressure in a gas cell for 1.0 -- 5.0 keV argon. Steven Bromley, Daniel Fox, Chad Sosolik, Jim Harriss, Joan Marler As a benchmark for theoretical studies on charge exchange interactions, we measured the charge exchange cross sections of interactions between fast ions and neutrals. A Bayard-Alpert gauge in the high vacuum regime provides relative pressure measurement of the injected target gas. Utilizing the beam attenuation method in the gas cell, we present absolute charge exchange cross sections for the interaction Ar$^{\mathrm{+\thinspace }}+$ Ar in the energy range 1.0- 5.0 keV consistent with other published work. Future experiments will use the gas cell for measuring singly and highly charged ion-neutral cross sections and producing high energy neutral beams with particle flux between 18 - 85 x 10$^{\mathrm{9}}$ s$^{\mathrm{-1}}$. [Preview Abstract] |
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W1.00052: Transfer of Momenta from Chiral SPP's onto Electrons Miguel Rangel In recent discovery, it is known that the plasmonic drag effect is due to the absorption of momentum from the surface plasmon polariton [SPP] and its transfer to electronic metal plasma, which leads to current. Similarly, one could expect that absorption of angular momentum of light should lead to circular currents. We believe that the most convenient structure to study this absorption of SPP angular momentum and the corresponding currents is metal nanowires. To find the chiral currents induced by propagation of chiral SPPs in metal nanowires, we will solve the corresponding Maxwell's equations in this structure and using this electromagnetic field distribution, we have found the forces acting on electrons and the resulting currents. After considering the multiple different modes of propagation in a 1D optical wave, we have found the transfer of momentum per unit time from the plasmonic fields onto the electrons in the wire. [Preview Abstract] |
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W1.00053: Progress Towards Charge Exchange with Highly Charged Ions Daniel Fox, Steve Bromley, Chad Sosolik, Joan Marler Highly charged ions (HCIs) are an integral component of atomic and molecular physics, in part because their compressed size and strong electric fields make them relevant to various areas of study, including quantum electrodynamics (QED). In addition, HCIs are often formed in conditions of extreme temperature or pressure, such as those found in astrophysics. These characteristics of HCIs increase the difficulty of HCI production in a laboratory setting compared to singly charged ions or neutral atoms, making HCIs less explored than other phenomena. Using HCIs created at the Clemson University Electron Beam Ion Trap (CUEBIT), we will study interactions between highly charged ions and neutral particles. A gas cell has been constructed in order to measure charge exchange cross-sections of these interactions. Results from measurements made with the gas cell will be presented along with ideas for further development of the system. These studies on HCIs will assist in studies pertaining to QED and astrophysics, and will also result in additional understanding of the structure and nature of HCIs themselves. [Preview Abstract] |
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W1.00054: Kinetics and Possible Mechanism of Photoinduced Optical Effects in Germanium Selenide Thin Films Josh Allen, Jonathan Bunton, Karel Palka, Miroslav Vlcek, Roman Golovchak, 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 order to fully take advantage of these unique properties the mechanisms of light interaction with the glassy matrix and in-situ time dependent behavior of structure and optical properties under irradiation must be further studied. Thermally evaporated films of GeSe$_{\mathrm{2}}$ were prepared and their photoinduced kinetics were studied as a function of temperature and incident wavelength. It was found that the films underwent both transient and non-transient changes in the optical transmittance. Non-transient changes manifested as photobleaching while transient changes manifested as photodarkening. Furthermore, the changes were found to follow a stretched exponential curve. The quantitative kinetic parameters, tau and beta, as well as the index of refraction, of the photoinduced optical changes have been evaluated and related to the different mechanisms of the photostructural transformations. [Preview Abstract] |
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W1.00055: Probing Surface Defects and Electronic Reconstruction on Nb-Doped SrTiO$_3$ Substrates Will Bowers, Patrick Gemperline, Miles Blanchet, Uchenna Ubeh, Joe Bersson, Tamara Isaacs-Smith, Michael Bozack, Sarit Dhar, Ryan Comes Dopants and surface termination quality both perform an incredibly important role in the performance and characteristics of thin films. We have studied the properties of Nb-doped films of SrTiO$_3$ given different surface and annealing treatments including deionized water and buffered HF etching. As a way to characterize these samples, we have performed atomic force microscopy, Rutherford backscattering spectrometry, X-Ray photoelectron Spectroscopy, electron transport and capacitance-voltage measurements. We found the annealing treatment to have a significant effect on electron transport through the film, and that the chemical termination of the film varied depending on which treatment was applied. [Preview Abstract] |
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W1.00056: The Required Response of a Surface Current of a Superconducting Sphere to an external Magnetic Monopole - found via an Analytical Extension of the Method of Images Eric Steinfelds, Keith Andrew Although magnetic monopoles have been highly elusive from discovery, it has not been possible to dismiss the existence of magnetic monopoles (i.e. 'monopoles') on quantum and classical theoretical grounds. Over the years, there have been proposed some sensitive measurements to detect obscure monopoles of the microscopic scale. In service to these efforts in basic science, we show a potential advantage in using superconductive spheroids to detect magnetic monopoles. Such round detectors are to be of microscopic or nanoscopic scale. When a monopole travels close to one of these detecting spheres, a Meisner (Ms`) surface current will form and increase as the monopole approaches. This escalation of Ms` current can be detected either with sensitive ammeter based electronic monitoring of the sphere or by subtle R.F. wave detections of the R.F. waves which are generated consequentially to the escalated currents. We have formulated to 1st and 2nd order precision the response of Ms` surface current on such a superconducting detection sphere to an external Magnetic Monopole. We used an analytical extension of the method of images compounded with the satisfying of the so called No-"Flux" Boundary Condition, which is used by academic engineers for heat transfer [1].\\ \\$[1]$ Online lecture material from Darthmouth College; Thayer School of Engieering of Dartmouth College; Course: "ENGS 43: Environmental Transport and Fate", taught by B. Cushman-Roisin; http://thayer.dartmouth.edu/~d30345d/courses/engs43 [Preview Abstract] |
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W1.00057: Synthesis and Observation of 2-Dimensional Frustration in a Tripod Kagome Lattice. Kyle Noordhoek, Jian Liu Magnetic frustration is an important phenomenon that challenge the fundamental theory of how spins should be aligned in a crystal lattice structure. To study this phenomenon further, our group plans to synthesize a newer family of compounds that exhibit frustration in a tripod kagome lattice. This lattice is comprised of a repeating pattern of corner sharing triangles that is difficult to produce in a laboratory setting and more difficult to find in the natural world. However recently, a compound that exhibits this kind of frustrated lattice has been synthesized. While interesting magnetic properties are seen in polycrystalline samples, a single crystalline sample is necessary for fully exploiting the two-dimensional magnetic interactions. Thus, we explore the possibility of growing epitaxial thin films and heterostructures by Pulsed Laser Deposition (PLD). To begin, we will first be growing a layer of (YTO) onto a Yttria-Stabilized Zirconia (YSZ) substrate. We have experimented with this growth already using a range of temperatures above 700C, only after having treated the YSZ substrates. In addition to these beginning growths, we have also begun treatment of the YTO crystal which involves the polishing of the crystal with a specialized lubricant. This is done to produce the flattest possible surface in which we can grow our final film on. Lastly, we have been able to calculate the lattice parameter of the corresponding YTO crystal. Throughout the processes, the topography of the samples is being monitored using the Atomic Force Microscope (AFM) while the phase is monitored using X-ray Powder Diffraction (XRD). [Preview Abstract] |
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W1.00058: Spectral threshold extended photoresponse in asymmetrical p-GaAs/AlGaAs heterostructure-based infrared detectors Dilip Chauhan, A. G. Unil Perera, Lianhe Li, Li Chen, Edmund H Linfield The spectral photoresponse threshold $\lambda_{t} $ of a semiconductor photodetector is conventionally determined by $\lambda_{t} =hc/\Delta $, where $\Delta $ is the minimum energy gap of a material, or the interfacial energy gap of a heterostructure. In addition, the $\Delta $ at the material interface is the key parameter to determine the dark current and noise levels of the detector. Therefore, lowering the $\Delta $ to detect longer spectral region will have a trade-off with increased noise levels. Here, we present infrared detection in very-long-wavelength infrared (VLWIR) in a detector designed with a $\Delta $ for mid-infrared (MIR) region, in p-GaAs/AlGaAs heterostructures. Specifically, a detector designed with $\Delta \quad =$ 0.40 eV ($\lambda_{t} =$ 3.1 \textmu m) showed an extended wavelength threshold up to 68 \textmu m, 45 \textmu m, and 60 \textmu m, under positive, zero, and negative biases respectively, at 5.3K. The dark current, however, was seen to correspond to $\Delta =$ 0.40 eV, which was confirmed by a fitting obtained by using a 3D carrier drift model. [Preview Abstract] |
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W1.00059: Salt-Assisted Ultrasonicated De-aggregation and Advanced Electrochemistry of Detonation Nanodiamond. Sanju Gupta, B. Evans, A. Henson Nanoparticles in dry powder state form agglomerates thus reducing surface energy and accessibility of diamond core impacting technological advancement. In this work, we investigated a facile, cost-effective and contaminant-free salt-assisted ultrasonic de-agglomeration method for detonation nanodiamond, NDs. Utilizing ultrasound energy to break apart two different sourced and thermally treated nanodiamond mesoscale aggregates in sodium chloride and sodium acetate salts, this technique produced aqueous slurry of isolated or single-digit (\textless 10 nm) stable colloidal dispersions by virtue of ionic interactions and electrostatic destabilization. Moreover, the technique is well-suited for materials engineering (composites, lubricants) and biomedical (bio-labelling, biosensing) applications. We characterized microscopic structure and performed advanced electrochemistry by immobilizing processed NDs on boron-doped diamond to study surface redox chemistry, determine surface potential (or Fermi level), carrier density and to image electrocatalytic activity by scanning electrochemical microscopy and the results are compared to those untreated aggregated nanodiamond particles. The findings are discussed in terms of surface functionality and defect sites that give rise to surface states within bandgap. These surface states may serve as electron donors (or acceptors) depending upon bonding (or antibonding) character suitable for various electrocatalytic redox processes. [Preview Abstract] |
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W1.00060: Nanoparticles-grafted functionalized graphene coated with nanostructured polyaniline layered nanocomposites as high-performance biosensors. Sanju Gupta, R. Meek The challenge remains to develop (chemical, electrochemical and biological) sensors from nanocomposites with broader electrical conductivity, molecular sensitivity and specificity. We report the design and synthesis of scalable, metal nanoparticles-grafted functionalized graphene overcoat with nanostructured polyaniline nanocomposites and elucidate their high-performance as advanced biosensors. The versatility of the nanocomposite performance was corroborated by altering the size, areal density and morphology of electrodeposited gold and silver nanoparticles (NPs) on the nitrogenated functionalized graphene (NFG) as well as the density of electropolymerized polyaniline (PANi) onto NFG. Gold and silver NPs are selected due to their higher electrical conductivity, facile synthesis, easier processability and scalability. The critical modification of architectures (NFG/Ag or AuNP/PANi) on FTO electrodes increased the conductivity of the electrodes significantly and reduced the charge transfer resistance dramatically while investigating electrochemical properties. The high-performance biosensing application is demonstrated for the detection of ascorbic acid (AA) over electroactive components interfering species commonly found in blood serum samples, with enhanced sensitivity over a range of detection thereby determining limit of detection. These nanocomposites are applicable for electrocatalysis, energy systems as well as enriching biofuel cell development. [Preview Abstract] |
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W1.00061: Binary gas mixture in a high speed channel Dr. Sahadev Pradhan The viscous, compressible flow in a 2D wall-bounded channel, with bottom wall moving in the positive $x-$ direction, simulated using the direct simulation Monte Carlo (DSMC) method, has been used as a test bed for examining different aspects of flow phenomenon and separation performance of a binary gas mixture at Mach number \textit{Ma }$=$\textit{ (U\textunderscore w / }$\backslash $\textit{sqrt(}$\gamma $\textit{ k\textunderscore B T\textunderscore w /m) }in the range\textit{ 0.1 \textless Ma \textless 30}, and Knudsen number \textit{Kn }$=$\textit{ 1/(}$\backslash $\textit{sqrt(2) }$\pi $\textit{ d\textasciicircum 2 n\textunderscore d H)} in the range \textit{0.1 \textless Kn \textless 10}. The generalized analytical model is formulated which includes the fifth order differential equation for the boundary layer at the channel wall in terms of master potential ($\chi )$, which is derived from the equations of motion in a 2D rectangular $(x - y)$ coordinate. The starting point of the analytical model is the Navier-Stokes, mass, momentum and energy conservation equations in the $(x - y)$ coordinate, where $x$ and $y$ are the streamwise and wall-normal directions, respectively. The linearization approximation is used ((Pradhan {\&} Kumaran\textit{, J. Fluid Mech -}2011); (Kumaran {\&} Pradhan, \textit{J. Fluid Mech -}2014)), where the equations of motion are truncated at linear order in the velocity and pressure perturbations to the base flow, which is an isothermal compressible Couette flow. Additional assumptions in the analytical model include high aspect ratio \textit{(L \textgreater \textgreater H)}, constant temperature in the base state (isothermal condition), and low Reynolds number (laminar flow). The analytical solutions are compared with direct simulation Monte Carlo (DSMC) simulations and found good agreement (with a difference of less than 10{\%}), provided the boundary conditions are accurately incorporated in the analytical solution. [Preview Abstract] |
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W1.00062: Multiphonon Raman spectroscopy and optical properties for graphene-family nanomaterials: Role of surface functionality on electronic and phonon density of states. B. Evans, A. Henson, R. Meek, N. Dimakis, S. Gupta We report optical and lattice vibrational properties of a range of graphene-family nanomaterials using UV-visible absorption, photoluminescence excitation, PLE and micro-Raman spectroscopy (RS) techniques. Various functionalized graphene nanomaterials include few layer graphene oxide, reduced graphene oxide, graphene quantum dots and three-dimensional graphene aerogel scaffolds and their nitrogenated counterparts. RS provides lattice dynamical nanoscale structural characterization revealing collective atomic/molecular motions and localized vibrations. The role of oxygen epoxy (C-O-C, carbonyl, C$=$O) and nitrogen (pryridinic and graphitic/pyrrolic) functionalities and corresponding bonding configurations with quantum size effects are emphasized in view of understanding physico-chemical properties for biosensing and water desalination. While first- and second-order phonon modes are analyzed in terms of Raman intensity, band position (intrinsic mechanical strain) and intensity ratio (structural disorder, number defect density), distinct localized $\pi $ electronic states were found in PLE spectra reflecting carbon atoms around oxygenated and nitrogenated species. The origin of these states is discussed based on experimental findings and DFT exemplifying structural evolution. [Preview Abstract] |
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W1.00063: Enhancement of Thermoelectric Performance of Lead Chalcogenides: PbTe, PbSe and PbS, Due To Temperature Dependent Light and Heavy Hole Valence Band Convergence. Kapila Wijayaratne, J. Zhao, C. Malliakas, U. Chatterjee Among many other interesting properties, Lead Chalcogenides are known for their remarkable thermoelectric performance. We have conducted temperature dependent Angle Resolved Photoemission Spectroscopy (ARPES) study of the electronic structures of Lead Chalcogenides, PbTe, PbSe and PbS. Our observations provide direct evidence for the existence of light-hole upper valence bands and so far undetected heavy-hole lower valence bands in these materials. An unusual temperature dependent relative movement between these bands was detected. This movement leads to a monotonic decrease in the energy separation between their maxima with the increase of temperature. This phenomenon is referred to as band convergence and is believed to be the driving factor behind extraordinary thermoelectric performances of Lead Chalcogenides at elevated temperatures. [Preview Abstract] |
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W1.00064: Preparing Atomically Flat Substrates for Oxide Film Synthesis Kevin Kleiner, Clayton Frederick, Jian Liu Substrates with Perovskite oxide structures (ABO$_{3}$) provide a useful base surface for growing artificial oxide layers through pulsed laser deposition (PLD). As-received substrate crystal pieces (10 x 5 x 0.5 mm$^{3})$ start with mixed termination as well as rough and possibly contaminated surface structures, but certain laboratory procedures can clean and treat the surface to prepare the substrate for growth. This methodology has been applied to SrTiO$_{3}$ (001) (STO), NdGaO$_{3}$ (001) (NGO), GdScO$_{3}$ (001) (GSO), and TbScO$_{3}$ (001) (TSO) substrates, and the resulting surface maps are analyzed at the micron level using atomic force microscopy (AFM). The results reveal that extended air annealing (temperatures $>$ 1,000$^{\circ}$C) most effectively removes terrace roughness and renders the step heights close to 0.4 nm for each substrate. Once the films are synthesized on a treated substrate, their unique electrical, magnetic, and functional properties can be studied with further experiments. [Preview Abstract] |
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W1.00065: Shining X-Ray Light on the Volume Collapse Phenomenon of Cerium Metal Brandon Scoggins, Bijuan Chen, Yang Ding, Cheng-Chien Chen Elemental rare-earth metals exhibit intriguing properties arising from strong correlation effects due to partially filled f-electron shells. Of particular interest is the volume collapse phenomenon observed under high pressure conditions. In this study, we perform calculations including hybridization effects and atomic multiplet interactions to model recent high-pressure X-ray Raman measurements on Ce metals. We find that the X-ray measurement after the volume collapse is compatible with a Kondo screening scenario. However, direct 4f-4f hopping as in the Mott-Hubbard model also provides a small screening channel. [Preview Abstract] |
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W1.00066: Algebraically Determining Rigid Unit Modes Shae Machlus Application-critical properties of crystals are often either inhibited or permitted by rigid unit modes (RUM's). RUM's are tilting patterns in crystal lattices that displace atoms, and they signify structural phase transitions between polymorphs of a given crystal. Previous efforts have been made to identify RUM's in several important materials classes. Strategies have been employed such as ball-and-spring simulations, phonon-frequency calculations, and trial-and-error searches. But no methodology has been as simple or exhaustive as the algebraic approach developed by Prof. Branton Campbell's group at Brigham Young University during the past year. [Preview Abstract] |
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W1.00067: Cadmium Telluride Solar Cell Simulations Using SCAPS Rylan Gordon, Spencer Shortt, Hasitha Mahabaduge The most prevalent thin-film solar cell in industrial production is the cadmium telluride (CdTe) Solar Cell. The role of cadmium sulfide (CdS) as the n-type buffer layer in CdTe solar cells is well studied. However, CdS limits the transmission of photons due to its higher bandgap. The work done in this project investigates the possibility of replacing CdS with magnesium doped zinc oxide. We simulated the effect of the optimal ratio of elemental composition, thickness of the layer, and the doping level, on efficiency of the solar cell, using SCAPS, a one dimensional solar cell simulator [1]. The simulation results and plans for the experimental study will be presented.~ [1] M. Burgelman, P. Nollet and S. Degrave, "Modelling polycrystalline semiconductor solar cells",~\textit{Thin Solid Films},~\textbf{361-362}, 527-532 (2000) [Preview Abstract] |
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W1.00068: Multilayer photoelectrodes with different sized TiO 2 nanoparticles for highly efficient Dye Sensitized Solar Cells. Zachary Patterson-Goss, K. H. Hettiarachchi, David Brooks, Landewatte DeSilva, T. M. W. J. Bandara Dye Sensitized Solar cells (DSSCs) are low cost, ecofriendly emerging alternative to photovoltaics. We prepared a series of multilayered photo-anodes for DSSCs which contained different sized TiO 2 nanoparticles. The casting of thin films was done by incorporating of spin coating technique. In DSSCs, TiO 2 films were sensitized with N719 dye complex. Polyacrylonitrile based quasi-solid- state electrolyte and Pt counter electrode were used to test their performances. For an optimized device, open photovoltage of 750 mV and a short circuit photocurrent of 20 mA/cm 2 were obtained under 1 sun illumination. A high efficiency of 7.5 {\%} is achieved but fill factor is only 50{\%}. The optical and electrical characteristics of the DSSC as well as morphological analysis of the films are presented. [Preview Abstract] |
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W1.00069: Properties of Quartic Mass Shells Thomas Mulkey, Maxim Durach If one compares different metamaterials from a common prospective, it appears that they can propagate a large variety of waves, depending on their individual properties. Specifically, one can control the shape of the mass shell for photons in the bulk metamaterials, modifying from the spherical shell to ellipsoidal and hyperbolic in hyperbolic metamaterials. Additionally, one can change the spin state of the photons by adding or combining birefringence and chirality. However, we are interested in an unknown material that supports photonic waves with a desired mass shell and desired spin state distribution over the mass shell. Starting from this set of photonic waves, we can find a set of 36 material properties, which such a material should have. Of particular note are the unique mass shells characterized by multivariate quartic equations. These mass shells represent novel metamaterials, and will be the topic of discussion in this poster. The discussed properties of these mass shells include asymptotic behavior, K near zero behavior, and non-trivial photonic spin. Mapping these mass shells will assist in the direct engineering of metamaterials propagating the appropriate optical waves for various situations. [Preview Abstract] |
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W1.00070: Quantum Many-Body Theory: Tensor Network Approach and Applications to Information Compression George Davila, Eduardo Mucciolo Tensor Networks may be used to describe the entanglement spectrum of Quantum Many-Body (QMB) systems in a manner which tells us about the entanglement between subsystems without loss of the description of the entire system. One such approach for 1D entanglement in gapped systems is the Matrix Product State (MPS) approach. While MPS-derived algorithms give us the entanglement spectrum for a QMB system, they similarly describe the singular value spectrum, corresponding to various patterns, in more general data sets. The MPS representation of any given set of data will therefore tell us about underlying structures in the data. Data sets which contain dominant patterns (i.e. localized subsystems) are compressible. Random sets (i.e. thermalized systems) are, to the contrary, incompressible. Not only can compressible systems be stored more compactly, but they also have a polynomial number of degrees of freedom and thus may be constructed (or deconstructed) via a finite quantum circuit array in polynomial time. Here we construct MPS representations for samples of DNA. We show that individual genes are relatively randomly structured and that one can exploit the properties of DNA so as to compress combinations of samples from multiple members of a given species. [Preview Abstract] |
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W1.00071: Characterization of Magnetic Anisotropy in Pt/Co/MgO Thin Films Nowsherwan Sultan, Aashish Subedi, Sajib Saha, Hasitha Mahabaduge, Shireen Adenwallah The anisotropy of a ferromagnet refers to the preferred direction of magnetization. Very thin films of Cobalt (Co) with thicknesses below about a nanometer display perpendicular magnetic anisotropy, a tendency for the magnetization to point out of the plane of the film. However, this is dependent on both the underlying seed layer and the capping overlayer. The anisotropy of Co films capped with MgO on Pt seed layers may be altered with thermal annealing. Here, we investigate changes in magnetic anisotropy as a function of the thickness of Cobalt and the effects of annealing. We find that both lower thicknesses of Cobalt and annealing shift the preferred magnetic anisotropy to the out of plane direction. [Preview Abstract] |
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W1.00072: Experimental Studies of Transport Properties of Novel Amorphous Fe-Tb-Dy-O Thin Films Alexandra Waters, Tatiana Allen, Humaira Taz, Ramki Kalyanaraman Novel amorphous material Fe-Tb-Dy-Oxide shows a remarkable combination of very high optical transparency, electrical conductivity, and Hall mobility. Material properties can be tuned by changing the R-value, the atomic ratio of iron to the two lanthanides, during the deposition. This makes the material a potential candidate for a wide range of applications in energy conversion, electronics, photonics, and spintronics. This work focuses on the transport properties of the samples with R-values between 6 and 12, which correspond to 8 - 14 {\%} of lanthanides in the iron oxide matrix. Films were grown by ion beam evaporation, then some films were annealed in various environments. Electrical resistivity, Hall Effect, and magnetoresistance were measured in the Van-der Pauw geometry at T$=$300 K in magnetic fields up to 13 kGs. The samples were heated to 700K, while resistivity and Hall Effect were monitored in-situ. After the samples cooled to T$=$300K, the transport properties were re-measured. This protocol was repeated for as long as the electrical contacts of a given sample remained linear. We will discuss the effect of the initial annealing on the sample properties as well the evolution of the transport properties of as-deposited samples as a result of the thermal cycling. [Preview Abstract] |
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W1.00073: Solution processed multilayers of Alq$_{\mathrm{3}}$ molecules and TiO$_{\mathrm{2}}$ nanoparticles for hybrid Bragg mirror Sarahn Nazaret, Amber Ethridge, Ajith DeSilva Tris (8-hydroxy) quinoline aluminum (Alq$_{\mathrm{3}})$ is a small-molecule-based organic compound with a low index of refraction. It has been widely used as a superior material for organic light emitting diodes. Colloidal titanium dioxide (TiO$_{\mathrm{2}})$ is constructed of inorganic nanoparticles having a very high index of refraction. They have been commonly used in thin-film optics. Multilayer structures of Alq$_{\mathrm{3}}$ molecules and TiO$_{\mathrm{2}}$ nanoparticles are successfully fabricated from solution process and using spin coating techniques. A structure consisting of alternating organic/inorganic layers exhibited the properties of a distributed Bragg reflector (DBR). The peak of the reflectivity for the constructed DBR was chosen as 530 nm, at which the emission of Alq$_{\mathrm{3}}$ occurred. For this device, the reflectivity over 90{\%} can be obtained with as few as five periods of the structure. Fabrication process and optical properties of the structure are presented. [Preview Abstract] |
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W1.00074: Design of Graphene Oxide UV-cut filter with visible spectrum transmittance optimized via thin-film interference Jeremy Low The geometry dependence of transmittance spectra in Graphene Oxide films is shown by thin-film interference in the UV-Vis spectrum. This effect has been shown to increase transmittance of a desired wavelength in the visible spectrum while decreasing transmittance in the UV-Vis spectrum at one-half the original wavelength. This effect can be controlled across the UV-Vis spectrum by modifying the mean thickness across the GO film. Furthermore it is shown that this can be utilized to design Graphene Oxide films that have high transmittance in the visible spectrum while blocking nearly 100$\%$ of UV radiation. [Preview Abstract] |
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W1.00075: Kinetics Study of Photo-Induced Optical Effects in Solution-based Arsenic Selenide Thin Films Maria White, Joshua Allen, Jonathan Bunton, Bryan Gaither, Megan McCracken, Justin Oelgoetz, Roman Golovchak, Andriy Kovalskiy Spin coated chalcogenide thin films have different structural and chemical properties than the films obtained by traditional methods such as thermal evaporation or sputtering. The solution-based method provides lower sensitivity of glass matrix to the influence of bandgap and superbandgap light. This property is very useful for non-linear optical applications based on high transparency of these materials in infrared spectral region. As$_{\mathrm{42}}$Se$_{\mathrm{58}}$ spin coated thin films were obtained by chemical dissolution of bulk arsenic selenide glasses in ethylenediamine. The influence of preparation conditions, especially the annealing temperatures at the final stage of thin films synthesis, on in-situ kinetics of photodarkening (bleaching) at various energies and intensities of UV-VIS light was studied. It was found that at certain annealing conditions only transient photoinduced effects can be obtained by eliminating metastable kinetic component. [Preview Abstract] |
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W1.00076: Characterization and Modeling of Behavior of Metamaterials as Shielding Against Directed Energy Weapons Richard Mattish, Dragoslav Grbovic In modern warfare, high-power microwave (HPM) weapons are a very real threat. Metamaterials, materials that gain their properties from their geometry or design rather than from their constituent materials, have unique absorption properties that can be tailored to desired frequencies. Our research makes use of finite element modeling as well as experimental measurements to evaluate the performance of various shield geometries constructed out of metamaterials as shields against microwave radiation. Special emphasis is given to using experimental measurements to refine and validate the finite element model so that we can accurately predict the performance of new shield geometries. [Preview Abstract] |
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W1.00077: Studying Mechanical Resonance with a Michelson Interferometer Arden Lesley, Michael Doucette, Seth Smith A Michelson Interferometer was used to study mechanical resonance in a magnetically-driven harmonic oscillator. One of the arms of the Michelson Interferometer was comprised of a mirror that was attached to the harmonic oscillator. As the oscillator vibrated, this caused changes in the interference by altering the path length difference between the interferometer's arms. When the oscillator reached a resonant frequency, this caused large increases in the amplitude of the vibration. The dependence of the resonant frequency of the mass of the harmonic oscillator was measured and the results were compared to predictions from theory. [Preview Abstract] |
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W1.00078: Key Encryption Through Quantum Optics. Madison Durrance, Zachary Galberd, Abbey Savage, Tristan Cabrera, Hauke Busch Cryptography has been around since the dawn of human civilization to send private messages for commercial, military, and political purposes. Some of the most important ciphers are the Vigen\`{e}re cipher, the enigma, and the more modern RSA. Because of the development of the internet, private encryption has also become increasingly more important. The weakest link of encryption is the key creation and key distribution. A key is needed to encrypt and decipher codes and is needed by both the user and sender. A solution to this problem is the generation of quantum key distributions. In our experiment, we are now trying to send and receive coded messages through photons after we build our quantum key distribution apparatus. The device will be secured against any form of eavesdropping because of the Heisenberg uncertainty principle. We will be able to know immediately if someone is listening in and if our key is compromised. [Preview Abstract] |
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W1.00079: Imaging Laser-Excited Blue LEDs Ruiming Chen, Collin Epstein, Tim Gfroerer, Yong Zhang Blue LEDs are known for their critical role in producing white light, since high-energy blue light is required to generate a spectrum of lower-energy light. In this experiment, we capture and analyze images of the optical emission from a blue LED under different temperatures and excitation conditions. Under non-uniform laser excitation, previous research has shown that light is emitted from areas without direct excitation. We call this phenomenon ELPE: Electro-Luminescence due to Photo-Excitation. Through further investigation, we find that LED droop (reduced device efficiency at high excitation) is only present in the ELPE from the non-excited area. At lower excitation levels, our theoretical model shows that heat loss is faster and more detrimental in the laser-excited region. These results provide important clues to the internal mechanisms that impede the performance of blue LEDs. [Preview Abstract] |
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W1.00080: Concurrent MultiPhoton microscopy and Magnetic Resonance Imaging (COMPMRI) Rebecca DiTusa Functional/Magnetic Resonance Imaging (f/MRI) systems have aided in medical research through the use of large field-of-view (FOV) imaging. However, high resolution, small FOV imaging would enhance the ability to analyze systems on a smaller, cellular scale. Two-photon microscopy has been used for deep-image small FOVs without a surgical procedure—but simultaneously achieving an MRI scan is difficult. Although scanning separately is achievable, it lacks the ability to definitively correlate events between scans due to the difference in time. In order to image a small and large FOV concurrently, a microscope constructed out of MRI-safe material is needed. To achieve this parameter, piezoelectric materials are used. They are MRI compatible and by using multiple orientations, motion in more than one dimension is possible. [Preview Abstract] |
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W1.00081: Volumetric Visualization Of X-RAY Phase Contrast Computed Tomography Collin Epstein, Daniel Boye, Ryan Goodner, Kyle Thompson, Amber Dagel X-ray phase contrast imaging (XPCI) utilizes the wave properties of X-rays to capture high-contrast radiographs of objects consisting of low-density materials that yield low-contrast, uninformative images. Combining XPCI with computed tomography (CT) enables the collection of high-contrast volumetric data of those low-density objects. We investigate the possibilities of rendering and examining the resulting data using three-dimensional (3D) visualization techniques and virtual reality (VR). [Preview Abstract] |
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W1.00082: Application of New Low Cost Technology for 2d-Flow Bound Resonance Method for Measurement of Fluid Flow. Ken McGill, Abigail Savage, Aidan Burleson, Cain Gantt, Joshua Moore, Kyle Cooley, Stephen Cave Proof of principle of the 2d-flow bound resonance method for measurement of fluid flow was established 2014. Devices employed for the measurement included 16 8-channel sample and hold Analog to Digital Converters (ADC), and 16 8-channel amplifiers. These devices were purchased in 2004. New devices available contain both the ADC and amplifier, and are available for much lower cost. The new devices are less defined for the application of 2d-flow bound resonance method for measurement of fluid flow. This presentation discusses the method for using current technology for 2d-flow bound resonance method for measurement of fluid flow. [Preview Abstract] |
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W1.00083: Refinement of Production Grade Biodiesel Ken McGill, Campbell Axt, Sydney Ninneman, Robert Hughly, Jillian Turner The modified Burton method for the thermal hydrogen-cracking of peanut oil has been investigated in the McGill Research Group since 2009. The successful and reliable production of biodiesel has been achieved since 2014. A hydrocarbon with viscosity similar to Production Grade Diesel will work in modern diesel engines. The current product has a viscosity significantly lower than production grade diesel. The starting material has a viscosity significantly higher than Production Grade Diesel. Current research is investigating methodologies to mix starting material and product to achieve target viscosity. [Preview Abstract] |
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W1.00084: Volumetric Radiography of Watermarks Ryan Stempert, Daniel Boye We explore the use of the volumetric radiography provided by Digitome in viewing watermarks on paper that are not visible to the unaided eye. The Digitome process uses multiple 2D radiographs taken from different perspectives to generate a user-defined plane of view. The x-ray source has a broadband spectrum generated, typically, from a 40keV electron beam incident upon a tungsten target. Transmission radiographs are captured with a digital radiography plate in communication with a computer. A watermark is a thinner, less dense area within a sheet of paper created by the manufacturer and usually visible by holding the paper up to the light. However, when the paper is mounted to an opaque material, this practice becomes impossible unless the mounting is removed, which can result in damage to the paper. Often, mounted paper and paintings on wood or canvas are not flat. We employed the Extended Depth of Field ImageJ plugin to aid in viewing non-planar objects. By optimizing acquisition and imaging parameters, we are able to discern watermarks through upwards of 40 mils of opaque mounting material, even beneath a layer of text. [Preview Abstract] |
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W1.00085: Graphene-based novel formulations as large-area nanofiltration membranes and mesoporous capacitive deionization electrodes for water desalination A. Henson, B. Evans, S. Gupta In this work, we developed large-area nanofiltration membranes using 1) shear aligned discotic nematic phase of graphene oxide and 2) holey graphenes with narrow hole size distribution via controlled catalytic oxidation. We also prepared interconnected network of mesoporous graphene-based electrodes to achieve optimal desalination during capacitive deionization (CDI) of brackish water, attributed to higher specific surface area, electrical conductivity, good wettability of water, environmentally safe, efficient pathways for ion and electron transportation, as potential successor of current filtration membranes. The pressure driven transport data on highly ordered, continuous, thin films of multi-layered graphene oxide and holey graphene is expected to demonstrate faster transport for salt water, higher retention for charged and uncharged organic probe molecules with hydrated radii above 5{\AA} as well as modest retention of mono- and di-valent salts for \textasciitilde 150 nm thick membranes. The highly ordered graphene nanosheets and nanoscaled porous graphene in the plane of the membrane make organized, molecule-hugging cylindrical and spherical channels, respectively, thus enhance the permeability and hydrodynamic conductivity. The results illustrate that both the macro and nanoscale pores are favorable for enhancing CDI performance by buffering ions to reduce the diffusion distance from external electrolyte to the interior surfaces and enlarging surface area. [Preview Abstract] |
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W1.00086: Infinity to Mesoscopic Systems through Sngle Molecular Magnets Herry Abdul-Hakim, P. Swantoro Since mesoscopic evolve stochastic system, the infinites abuse can be prevent by took $\infty $ as integral boundary from $e $through transformation [n!/s$^{\mathrm{n-1}}$]$e^{-st\thinspace }$0\textbar $\infty \quad =$ [n!/n$^{\mathrm{n+1\thinspace }}$] That agai express not any $\infty $ to be in coincidences with ``present value'' y $=$ [(a)/(1$+$ (r/n)$^{\mathrm{nx\thinspace }})$] whereas if n $\to \infty $ y $=$ [ a (e$^{\mathrm{rx\thinspace }})$] to final-Project in UI/2007 retrieves \textbf{``Mesoscopic {\&} Nanostructured Materials'' }further emerge the proton-neutron {\&} electron Atom-combined from single Mn$_{\mathrm{12\thinspace }}$molecular magnets of electrons transport [to X Zotos {\&} P Prelovsek ], proton toward other protons [A Goswami\textbraceright {\&} ``Molecular Magnets'' -- Neutrons {\&} New Materials depicted in ``dissipativity'' of lifetime as well as ``depreciation'' of [SSC] to ``depression''. V Chandrasekhar decribes in ``Single-Molecule Magnets'' gave (r-2R)/(2a$_{\mathrm{o}}) \quad =$ 1 between 1/R[1- $e^{-2R/a}_{o}$( 1 $+$ (R/a$_{\mathrm{o}})$]-Goswami , h 432 and $\smallint $ [ 1 -- (\textit{r/2a}$_{o})$] $e^{-r/ao\thinspace }r^{4}$\textit{dr}-Agus Purwanto,PhD --h 299. [Preview Abstract] |
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W1.00087: Studying High-dimensional Supersymmetry Models with Neural Networks Alexander Karbo, Michelle Kuchera This research project investigated the feasibility of using neural networks to more easily study high-dimensional supersymmetry models, using the phenomenological Minimal Supersymmetric Standard Model (pMSSM) as the test case. Facilities such as the Large Hadron Collider are currently conducting experiments to search for evidence of physics beyond the Standard Model (BSM); supersymmetry is one of these candidates. Direct methods of searching for evidence of supersymmetry models are intractable due to computational limitations. Bayesian Neural Networks (BNNs) were used to generate predictions directly from a point in the pMSSM parameter space without needing to simulate particle collisions. This work focused on predicting cross-sections resulting from 13TeV proton-proton collisions. The training data was generated fusing the SUSY-HIT and Prospino codes. Once trained, the BNN provides a function for high-energy physicists to more readily explore the parameter space of the pMSSM and other BSM models. [Preview Abstract] |
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W1.00088: Magnetic Field Measurements for the Search for Mirror Matter. Shaun Vavra, Ben Chance, Ben Rybolt, Yuri Kamyshkov, Joshua Barrow, Leah Broussard The mirror matter hypothesis is a relatively new idea which extends the Standard Model with an exact copy of itself. Interactions with this new sector of matter are seldom, save for gravity; thus, it becomes a viable dark matter candidate. Mixing interactions between the two sectors can lead to neutral particle oscillations, including neutrons, which can oscillate back and forth dependent upon magnetic strength and alignment. Thus, control of environmental magnetic fields are important to test for this novel theory, and possibly infer the existence of a dark sector. Using modern, portable, inexpensive commercial hardware, and open source software, characterizations of the ambient magnetic field and preparations for a full-scale experiment are underway at the HFIR facility at ORNL. Our work is a crucial first step in the measurement of the magnetic fields pertinent to our future experiment. We hope to make full scale magnetic field control systems soon. [Preview Abstract] |
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W1.00089: Neutron-Antineutron Oscillation and Annihilation on C-12 at the European Spallation Source Charles Ladd, Yuri Kamyshkov, Ben Rybolt, Joshua Barrow, Elena Golubeva In the Standard Model, baryon and lepton number (B, L) are conserved. However, Sakharov showed that in the early universe violation of B was a requirement to explain the matter-antimatter asymmetry. One type of B violation being focused on at the ESS is that of neutron-antineutron oscillation (n---\~{n}), a $\Delta $B $=$ 2 process, thus showing that baryon number is not conserved. The ESS aims to search for n---\~{n} at a soon to be constructed, high-intensity neutron beamline. There, if n---\~{n} occurs, the neutron will travel down the beamline, oscillate into an antineutron, and hit a target of carbon nanofoil; this is similar to a previous search at the ILL in Grenoble. On this nanofoil, annihilation to mesons would occur with individual carbon nuclei, those mesons being collected on a high-resolution detector. Currently, MC data generation and analysis is underway for the ESS collaboration with the aid of E. Golubeva, hoping to properly model the appropriate nuclear interactions. For purposes of validation and verification, this work provides a detailed overview of antinucleon-nucleon annihilation properties. It is important to study such generated data in order to make more definite predictions of the efficiency for the detection of n---\~{n}. [Preview Abstract] |
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W1.00090: 3D Printing Plastic Scintillators Madison Durrance, Nicolas Merino, Nowsherwan Sultan, Ralph France, Sharon Carceccia We are continuing our work from last year of developing cost-effective 3D printed scintillators. There are various methods for manufacturing scintillators, but unfortunately many of these methods involve the costly machining of crystal materials. We plan to reduce this cost by attempting to manufacture plastic scintillators using a 3D printer. The challenges of this project are in printing completely transparent objects and successfully integrating an organic, scintillating molecule into plastic (T-Glase, a type of PET). We have had success in printing with PET filament, the same polyester used in disposable plastic bottles. Upon successful clear prints and efficient chemical doping of PET plastic with naphthalene, we intend to use recycled water bottles to manufacture our own scintillating fiber. [Preview Abstract] |
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W1.00091: Sensitivity of stellar electron-capture rates to parent neutron number: A case study on a continuous chain of twenty Vanadium isotopes G.W. Hitt, S.S. Gupta, R.G.T. Zegers, R. Titus, C. Sullivan, B. A. Brown, A.L. Cole, S. Shams Gamow-Teller (GT) strength distributions (B(GT)) in electron-capture (EC) daughters stemming from the parent ground state are computed with the shell-model in the full pf-shell space, with QRPA in the formalism of Krumlinde and M$\backslash $"oller and with an Approximate Method for assigning an effective B(GT). These are compared to data available from decay and charge-exchange (CE) experiments across titanium isotopes in the pf-shell from A$=$43 to A$=$62, the largest set available for any chain of isotopes in the pf-shell. The present study is the first to examine B(GT) and the associated EC rates across a particular chain of isotopes with the purpose of examining rate sensitivities as neutron number increases. EC rates are also computed for a wide variety of stellar electron densities and temperatures providing concise estimates of the relative size of rate sensitivities for particular astrophysical scenarios. This work underscores the need for CE experiments in inverse kinematics on neutron-rich nuclei at future RIB Facilities. [Preview Abstract] |
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W1.00092: Development of a CompCal Calorimeter for the eta-Primakoff Experiment at JLab Nicholas Sterling The eta-Primakoff experiment (E12-10-011) is aimed to perform a precision measurement of the eta radiative decay width via the Primakoff effect in Hall D to determine the light quark-mass ratio and the eta-eta\textasciiacute mixing angle. In addition to using the standard GlueX apparatus, a compact, high resolution electromagnetic calorimeter (CompCal) will be critical for controlling the experimental systematic uncertainty by detecting the electron Compton scattering in parallel to the physics production. In order to investigate the possibility of adding a scintillating hodoscope in front of CompCal for the charged particle identification, I performed Monte Carlo simulations to study two primary quantities of interest, namely, the back splash from CompCal and the electromagnetic background rate. The result of this study will be presented. [Preview Abstract] |
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W1.00093: Unlocking Neutrinoless Double-Beta Decay through Radon Deposition Andrew Dunton In our universe, there is a preponderance of matter over antimatter. Neutrinoless double-beta decay would serve as a potential mechanism by which this phenomenon, called the asymmetry of matter and antimatter, occurs. In a single beta decay, a proton decays into a neutron and releases a beta particle (electron) and an electron neutrino. In a theoretical double-beta decay, two protons would decay, and two electrons would be released, but no neutrinos would be detected. This would mean the electron neutrino is its own antiparticle, a Majorana particle. In order to observe this phenomenon, one requires a large collection of nucleons prone to beta decay far away from any potential sources of interference. Thus, the MAJORANA experiment consists of 40kg of Germanium buried undergrounded and encased in lead shielding. One of the potential background interference sources is alpha radiation from radon gas, which permeates the earth and air around us. Its interference levels in the first trial runs of the experiment were much higher than expected, and so reducing radon's presence has become a priority. In order to do this, we must understand how it attaches itself to various materials and in various conditions, and how best to remove it. [Preview Abstract] |
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W1.00094: Extraction of unpolarized TMD widths using collinearity criteria with HERMES multiplicities in semi-inclusive deep-inelastic scattering Mason Albright Using a Gaussian ansatz for the transverse momentum dependence of unpolarized transverse momentum dependent (TMD) functions, we analyze HERMES multiplicities in semi-inclusive deep-inelastic scattering (SIDIS). We discuss the importance of data selection in conducting the fit, where, in particular, we implement for the first time new collinearity criteria that allow us to better separate the current and target fragmentation regions. We compare our parameters to previous extractions in order to better interpret our results. We also give an outlook on what impact this criterion can have on on-going and future experiments. [Preview Abstract] |
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