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2019

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Articles 121 - 150 of 1393

Full-Text Articles in Physics

Millimeter-Wavelength Characterization Of The Co Emission Of Comets 174p/Echeclus, 29p/Schwassmann-Wachmann, And C/2016 R2 (Panstarrs), Kacper Wierzchos Nov 2019

Millimeter-Wavelength Characterization Of The Co Emission Of Comets 174p/Echeclus, 29p/Schwassmann-Wachmann, And C/2016 R2 (Panstarrs), Kacper Wierzchos

USF Tampa Graduate Theses and Dissertations

Comets are fascinating minor solar system bodies. They contain some of the most pristine and unprocessed material found in the solar system. As a comet approaches the Sun it displays the characteristic cometary coma and tail. This is due to the release of volatile species through a variety of processes. In the present work I studied the carbon monoxide emission of three very unique comets; 174P/Echeclus, 29P/Schwassmann-Wachmann and C/2016 R2 (PanSTARRS) with different radio telescopes at millimeter wavelengths. After molecular hydrogen, carbon monoxide is the second most abundant molecule in the universe, and is also the most volatile of the …

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Aluminum Secondary Electron Yield, Jr Dennison, Phillip Lundgreen Nov 2019

Aluminum Secondary Electron Yield, Jr Dennison, Phillip Lundgreen

Browse all Datasets

Accurate modeling of spacecraft charging is essential to mitigate well-known and all-too-common deleterious and costly effects on spacecraft resulting from charging induced by interactions with the space plasma environment. This paper addresses how limited availability of electron emission and transport properties of spacecraft materials—in particular secondary electron yields—and the wide range measured for such properties pose a critical issue for modeling spacecraft charging. It describes a materials charging database being developed, which when used in concert with the strategies outlined herein for best practices for establishing optimized materials properties for spacecraft charging models and specific mission requirements and how these …

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Experimental Testing Of A 3d-Printed Metamaterial Slow Wave Structure For High Power Microwave Generation, Antonio B. De Alleluia Nov 2019

Experimental Testing Of A 3d-Printed Metamaterial Slow Wave Structure For High Power Microwave Generation, Antonio B. De Alleluia

Electrical and Computer Engineering ETDs

A metamaterial (MTM) high power microwave (HPM) vacuum electron device (VED) was developed using 3D printing technology. The specific geometric pattern of the source can produce both negative permittivity and permeability to interact with a relativistic electron beam. The electron beam is generated using a pulsed electron accelerator with a maximum energy of 700 keV and lasting approximately 16 ns. The design of this novel VED consists of a circular waveguide loaded with complementary split-ring resonators in a linear periodic arrangement in which the relativistic beam travels guided by a magnetic field. The electrons interact with the MTM producing electromagnetic …

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Smooth Flow In Diamond: Atomistic Ductility And Electronic Conductivity, Chang Liu, Xianqi Song, Quan Li, Yanming Ma, Changfeng Chen Nov 2019

Smooth Flow In Diamond: Atomistic Ductility And Electronic Conductivity, Chang Liu, Xianqi Song, Quan Li, Yanming Ma, Changfeng Chen

Physics & Astronomy Faculty Research

Diamond is the quintessential superhard material widely known for its stiff and brittle nature and large electronic band gap. In stark contrast to these established benchmarks, our first-principles studies unveil surprising intrinsic structural ductility and electronic conductivity in diamond under coexisting large shear and compressive strains. These complex loading conditions impede brittle fracture modes and promote atomistic ductility, triggering rare smooth plastic flow in the normally rigid diamond crystal. This extraordinary structural change induces a concomitant band gap closure, enabling smooth charge flow in deformation created conducting channels. These startling soft-and-conducting modes reveal unprecedented fundamental characteristics of diamond, with profound …

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Melissa: System Description And Spectral Features Of Pre- And Post-Midnight F-Region Echoes, Fabiano S. Rodrigues, Weijia Zhan, Marco A. Milla, B. G. Fejer, Eurico R. De Paula, Acacio C. Neto, Angela M. Santos, Inez S. Batista Nov 2019

Melissa: System Description And Spectral Features Of Pre- And Post-Midnight F-Region Echoes, Fabiano S. Rodrigues, Weijia Zhan, Marco A. Milla, B. G. Fejer, Eurico R. De Paula, Acacio C. Neto, Angela M. Santos, Inez S. Batista

All Physics Faculty Publications

Most of the low‐latitude ionospheric radar observations in South America come from the Jicamarca Radio Observatory, located in the western longitude sector (∼75°W). The deployment of the 30 MHz FAPESP‐Clemson‐INPE (FCI) coherent backscatter radar in the magnetic equatorial site of São Luis, Brazil, in 2001 allowed observations to be made in the eastern sector (∼45°W). However, despite being operational for several years (2001–2012), FCI only made observations during daytime and pre‐midnight hours, with a few exceptions. Here, we describe an upgraded system that replaced the FCI radar and present results of full‐night F‐region observations. This radar is referred to …

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Why The Crackling Deformations Of Single Crystals, Metallic Glasses, Rock, Granular Materials, And The Earth’S Crust Are So Surprisingly Similar, Karin A. Dahmen, Jonathan T. Uhl, Wendelin J. Wright Nov 2019

Why The Crackling Deformations Of Single Crystals, Metallic Glasses, Rock, Granular Materials, And The Earth’S Crust Are So Surprisingly Similar, Karin A. Dahmen, Jonathan T. Uhl, Wendelin J. Wright

Faculty Journal Articles

Recent experiments show that the deformation properties of a wide range of solid materials are surprisingly similar. When slowly pushed, they deform via intermittent slips, similar to earthquakes. The statistics of these slips agree across vastly different structures and scales. A simple analytical model explains why this is the case. The model also predicts which statistical quantities are independent of the microscopic details (i.e., they are "universal"), and which ones are not. The model provides physical intuition for the deformation mechanism and new ways to organize experimental data. It also shows how to transfer results from one scale to another. …

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Planck's And Callendar's Blackbody Radiation Formulas And Their Fitness To Experimental Data, Max Tran Nov 2019

Planck's And Callendar's Blackbody Radiation Formulas And Their Fitness To Experimental Data, Max Tran

Publications and Research

In this paper, we compare the blackbody radiation density formula obtained with classical physics by Hugh L Callendar and the formula obtained by Max Planck using quantization of energy. We use R and Maxima to analyze their fitness on coordinating experimental data and indicate some limitations with experiments in this area.

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Weaponizing Radioactive Medical Waste - The Looming Threat, Shreekumar Menon, Vagish Kumar L.S. Nov 2019

Weaponizing Radioactive Medical Waste - The Looming Threat, Shreekumar Menon, Vagish Kumar L.S.

International Journal of Nuclear Security

Across the globe, use of radioactive substances for medical treatment, by hospitals has resulted in generation of toxic wastes on a large scale. Disposal of these wastes are being entrusted to waste disposal vendors. Environmental concerns, pressures, restrictions and high labor costs, compel these vendors to dump these wastes in third world countries, where enforcement and awareness are substantially low. Unrestricted access to these waste dumps is an open invitation to terror organizations to extract toxic substances and fabricate crude dirty bombs to threaten public safety, and cause low-level contamination of sensitive installations. It is therefore imperative to create an …

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Analytical Treatment Of The Interaction Quench Dynamics Of Two Bosons In A Two-Dimensional Harmonic Trap, G. Bougas, Simeon I. Mistakidis, P. Schmelcher Nov 2019

Analytical Treatment Of The Interaction Quench Dynamics Of Two Bosons In A Two-Dimensional Harmonic Trap, G. Bougas, Simeon I. Mistakidis, P. Schmelcher

Physics Faculty Research & Creative Works

We Investigate The Quantum Dynamics Of Two Bosons, Trapped In A Two-Dimensional Harmonic Trap, Upon Quenching Arbitrarily Their Interaction Strength And Thereby Covering The Entire Energy Spectrum. Utilizing The Exact Analytical Solution Of The Stationary System, We Derive A Closed Analytical Form Of The Expansion Coefficients Of The Time-Evolved Two-Body Wave Function, Whose Dynamics Is Determined By An Expansion Over The Postquench Eigenstates. The Emergent Dynamical Response Of The System Is Analyzed In Detail By Inspecting Several Observables Such As The Fidelity, The Reduced One-Body Densities, The Radial Probability Density Of The Relative Wave Function In Both Real And Momentum …

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Vimentin Protects Cells Against Nuclear Rupture And Dna Damage During Migration, Alison E. Patteson, Amir Vahabikashi, Katarzyna Pogoda, Stephen A. Adam, Kalpana Mandal, Mark Kittisopikul, Suganya Sivagurunathan, Anne Goldman, Robert D. Goldman, Paul A. Janmey Nov 2019

Vimentin Protects Cells Against Nuclear Rupture And Dna Damage During Migration, Alison E. Patteson, Amir Vahabikashi, Katarzyna Pogoda, Stephen A. Adam, Kalpana Mandal, Mark Kittisopikul, Suganya Sivagurunathan, Anne Goldman, Robert D. Goldman, Paul A. Janmey

Physics - All Scholarship

Mammalian cells frequently migrate through tight spaces during normal embryogenesis, wound healing, diapedesis, or in pathological situations such as metastasis. Nuclear size and shape are important factors in regulating the mechanical properties of cells during their migration through such tight spaces. At the onset of migratory behavior, cells often initiate the expression of vimentin, an intermediate filament protein that polymerizes into networks extending from a juxtanuclear cage to the cell periphery. However, the role of vimentin intermediate filaments (VIFs) in regulating nuclear shape and mechanics remains unknown. Here, we use wild-type and vimentin-null mouse embryonic fibroblasts to show that VIFs …

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An Introduction To Shape Dynamics, Patrick R. Kerrigan Nov 2019

An Introduction To Shape Dynamics, Patrick R. Kerrigan

Physics

Shape Dynamics (SD) is a new fundamental framework of physics which seeks to remove any non-relational notions from its methodology. importantly it does away with a background space-time and replaces it with a conceptual framework meant to reflect direct observables and recognize how measurements are taken. It is a theory of pure relationalism, and is based on different first principles then General Relativity (GR). This paper investigates how SD assertions affect dynamics of the three body problem, then outlines the shape reduction framework in a general setting.

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Measurement Of Electron Density And Temperature From Laser-Induced Nitrogen Plasma At Elevated Pressure (1–6 Bar), Ashwin P. Rao [*], Mark Gragston, Anil K. Patnaik, Paul S. Hsu, Michael B. Shattan Nov 2019

Measurement Of Electron Density And Temperature From Laser-Induced Nitrogen Plasma At Elevated Pressure (1–6 Bar), Ashwin P. Rao [*], Mark Gragston, Anil K. Patnaik, Paul S. Hsu, Michael B. Shattan

Faculty Publications

Laser-induced plasmas experience Stark broadening and shifts of spectral lines carrying spectral signatures of plasma properties. In this paper, we report time-resolved Stark broadening measurements of a nitrogen triplet emission line at 1–6 bar ambient pressure in a pure nitrogen cell. Electron densities are calculated using the Stark broadening for different pressure conditions, which are shown to linearly increase with pressure. Additionally, using a Boltzmann fit for the triplet, the electron temperature is calculated and shown to decrease with increasing pressure. The rate of plasma cooling is observed to increase with pressure. The reported Stark broadening based plasma diagnostics in …

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Measuring And Utilizing High-Dimensional Information Of Optical Fields, Ziyi Zhu Nov 2019

Measuring And Utilizing High-Dimensional Information Of Optical Fields, Ziyi Zhu

USF Tampa Graduate Theses and Dissertations

Currently, many areas of optical techniques including imaging, inspection and communication emphasize the utilization of the high-dimensional information encoded in optical fields. There is also a requirement for novel measurement techniques to extract this high-dimensional information with high-speed and accuracy. We firstly introduce a scan-free direct measurement technique that is capable of simultaneously characterizing the amplitude and phase of a coherent scalar optical field. Our direct measurement approach is constituted of a weak polarization perturbation which is followed by the recording of a polarization-resolving imaging process. The weak perturbation rotates the linear polarization on the spatial frequency domain of the …

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Spatial Multiplexing Of Squeezed Light By Coherence Diffusion, Jian Sun, (...), Eugeniy E. Mikhailov, Irina Novikova, Et Al. Nov 2019

Spatial Multiplexing Of Squeezed Light By Coherence Diffusion, Jian Sun, (...), Eugeniy E. Mikhailov, Irina Novikova, Et Al.

Arts & Sciences Articles

Spatially splitting nonclassical light beams is in principle prohibited due to noise contamination during beam splitting. We propose a platform based on thermal motion of atoms to realize spatial multiplexing of squeezed light. Light channels of separate spatial modes in an antirelaxation coated vapor cell share the same long-lived atomic coherence jointly created by all channels through the coherent diffusion of atoms, which in turn enhances the individual channel’s nonlinear process responsible for light squeezing. Consequently, it behaves as squeezed light in one optical channel transferring to other distant channels even with laser powers below the threshold for squeezed light …

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From Critical Behavior To Catastrophic Runaways: Comparing Sheared Granular Materials With Bulk Metallic Glasses, Alan A. Long, Dmitry Denisov, Peter Schall, Todd C. Hufnagel, Xiaojun Gu, Wendelin J. Wright, Karin A. Dahmen Nov 2019

From Critical Behavior To Catastrophic Runaways: Comparing Sheared Granular Materials With Bulk Metallic Glasses, Alan A. Long, Dmitry Denisov, Peter Schall, Todd C. Hufnagel, Xiaojun Gu, Wendelin J. Wright, Karin A. Dahmen

Faculty Journal Articles

The flow of granular materials and metallic glasses is governed by strongly correlated, avalanche-like deformation. Recent comparisons focused on the scaling regimes of the small avalanches, where strong similarities were found in the two systems. Here, we investigate the regime of large avalanches by computing the temporal profile or “shape” of each one, i.e., the time derivative of the stress-time series during each avalanche. We then compare the experimental statistics and dynamics of these shapes in granular media and bulk metallic glasses. We complement the experiments with a mean-field model that predicts a critical size beyond which avalanches turn into …

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Average Speech Directivity, Samuel D. Bellows, Claire M. Pincock, Jennifer K. Whiting, Timothy W. Leishman Nov 2019

Average Speech Directivity, Samuel D. Bellows, Claire M. Pincock, Jennifer K. Whiting, Timothy W. Leishman

Directivity

Speech directivity describes the angular dependence of acoustic radiation from a talker’s mouth and nostrils and diffraction about his or her body and chair (if seated). It is an essential physical aspect of communication affecting sounds and signals in acoustical environments, audio, and telecommunication systems. Because high-resolution, spherically comprehensive measurements of live, phonetically balanced speech have been unavailable in the past, the authors have undertaken research to produce and share such data for simulations of acoustical environments, optimizations of microphone placements, speech studies, and other applications. The measurements included three male and three female talkers who repeated phonetically balanced passages …

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Search For Gravitational-Wave Signals Associated With Gamma-Ray Bursts During The Second Observing Run Of Advanced Ligo And Advanced Virgo, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, W. H. Wang Nov 2019

Search For Gravitational-Wave Signals Associated With Gamma-Ray Bursts During The Second Observing Run Of Advanced Ligo And Advanced Virgo, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, W. H. Wang

Physics and Astronomy Faculty Publications and Presentations

We present the results of targeted searches for gravitational-wave transients associated with gamma-ray bursts during the second observing run of Advanced LIGO and Advanced Virgo, which took place from 2016 November to 2017 August. We have analyzed 98 gamma-ray bursts using an unmodeled search method that searches for generic transient gravitational waves and 42 with a modeled search method that targets compact-binary mergers as progenitors of short gamma-ray bursts. Both methods clearly detect the previously reported binary merger signal GW170817, with p-values of z ≤ 1. We estimate 0.07–1.80 joint detections with Fermi-GBM per year for the 2019–20 …

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Longitudinal Bunch Profile Diagnostic For Magnetized Electron Beams, Mark Stefani, Fay Hannon Nov 2019

Longitudinal Bunch Profile Diagnostic For Magnetized Electron Beams, Mark Stefani, Fay Hannon

Electrical & Computer Engineering Faculty Publications

The study of magnetized electron beam has become a high priority for its use in ion beam cooling as part of electron ion colliders and the potential of easily forming flat beams with a large aspect ratio. In this paper, a new diagnostic is described with the purpose of studying longitudinal and transverse magnetized beam properties. The device is a modification to a typical pepper-pot. Specifically, this 1D pepper-pot was designed for use with a transverse deflecting cavity for longitudinal bunch profile measurements of magnetized beams.

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Measurement Of The Cross Sections For Inclusive Electron Scattering In The E12-14-012 Experiment At Jefferson Lab, M. Murphy, H. Dai, D. Abrams, A. M. Ankowski, B. Aljawrneh, S. Alsalmi, J. Bane, S. Barcus, O. Benhar, V. Bellini, J. Bericic, D. Biswas, A. Camsonne, J. Castellanos, J.-P. Chen, M. E. Christy, K. Craycraft, R. Cruz-Torres, D. Day, S.-C. Dusa, E. Fuchey, T. Gautam, C. Giusti, J. Gomez, C. Gu, T. Hague, J.-O. Hanson, F. Hauenstein, D. W. Higinbotham, C. E. Hyde, C. M. Jen, C. Keppel, S. Li, R. Lindgren, H. Liu, C. Mariani, R. E. Mcclellan, D. Meekins, R. Michaels, M. Mihovilovic, D. Nguyen, M. Nycz, L. Ou, B. Pandey, V. Pandey, K. Park, G. Perera, A. J. R. Puckett, S. N. Santiesteban, S. Širca, T. Su, L. Tang, Y. Tian, N. Ton, B. Wojtsekhowski, S. Wood, Z. Ye, J. Zhang, The Jefferson Lab Hall A Collaboration Nov 2019

Measurement Of The Cross Sections For Inclusive Electron Scattering In The E12-14-012 Experiment At Jefferson Lab, M. Murphy, H. Dai, D. Abrams, A. M. Ankowski, B. Aljawrneh, S. Alsalmi, J. Bane, S. Barcus, O. Benhar, V. Bellini, J. Bericic, D. Biswas, A. Camsonne, J. Castellanos, J.-P. Chen, M. E. Christy, K. Craycraft, R. Cruz-Torres, D. Day, S.-C. Dusa, E. Fuchey, T. Gautam, C. Giusti, J. Gomez, C. Gu, T. Hague, J.-O. Hanson, F. Hauenstein, D. W. Higinbotham, C. E. Hyde, C. M. Jen, C. Keppel, S. Li, R. Lindgren, H. Liu, C. Mariani, R. E. Mcclellan, D. Meekins, R. Michaels, M. Mihovilovic, D. Nguyen, M. Nycz, L. Ou, B. Pandey, V. Pandey, K. Park, G. Perera, A. J. R. Puckett, S. N. Santiesteban, S. Širca, T. Su, L. Tang, Y. Tian, N. Ton, B. Wojtsekhowski, S. Wood, Z. Ye, J. Zhang, The Jefferson Lab Hall A Collaboration

Physics Faculty Publications

The E12-14-012 experiment performed at Jefferson Lab Hall A has collected inclusive electron-scattering data for different targets at the kinematics corresponding to beam energy 2.222 GeV and scattering angle 15.54°. Here we present a comprehensive analysis of the collected data and compare the double-differential cross sections for inclusive scattering of electrons, extracted using solid targets (aluminum, carbon, and titanium) and a closed argon-gas cell. The data extend over broad range of energy transfer, where quasielastic interaction, Δ-resonance excitation, and inelastic scattering yield contributions to the cross section. The double-differential cross sections are reported with high precision (∼3%) for all targets …

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Collinear Factorization In Wide-Angle Hadron Pair Production In E + E − Annihilation, E. Moffat, T. C. Rogers, N. Sato, A. Signori Nov 2019

Collinear Factorization In Wide-Angle Hadron Pair Production In E + E − Annihilation, E. Moffat, T. C. Rogers, N. Sato, A. Signori

Physics Faculty Publications

We compute the inclusive unpolarized dihadron production cross section in the far from back-to-back region of e+ e− annihilation in leading order pQCD using existing fragmentation function fits and standard collinear factorization, focusing on the large transverse momentum region where transverse momentum is comparable to the hard scale (the center-of-mass energy). We compare with standard transverse-momentum-dependent (TMD) fragmentation function-based predictions intended for the small transverse momentum region with the aim of testing the expectation that the two types of calculation roughly coincide at intermediate transverse momentum. We find significant tension, within the intermediate transverse momentum region, between calculations done with …

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A Rotating Aperture Mask For Small Telescopes, Edward L. Foley Nov 2019

A Rotating Aperture Mask For Small Telescopes, Edward L. Foley

Master's Theses

Observing the dynamic interaction between stars and their close stellar neighbors is key to establishing the stars’ orbits, masses, and other properties. Our ability to visually discriminate nearby stars is limited by the power of our telescopes, posing a challenge to astronomers at small observatories that contribute to binary star surveys. Masks placed at the telescope aperture promise to augment the resolving power of telescopes of all sizes, but many of these masks must be manually and repetitively reoriented about the optical axis to achieve their full benefits. This paper introduces a design concept for a mask rotation mechanism that …

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Angular Memory Effect Of Transmission Eigenchannels, Hasan Yllmaz, Chia Wei Hsu, Arthur Goetschy, Stefan Bittner, Stefan Rotter, Alexey Yamilov, Hui Cao Nov 2019

Angular Memory Effect Of Transmission Eigenchannels, Hasan Yllmaz, Chia Wei Hsu, Arthur Goetschy, Stefan Bittner, Stefan Rotter, Alexey Yamilov, Hui Cao

Physics Faculty Research & Creative Works

The optical memory effect has emerged as a powerful tool for imaging through multiple-scattering media; however, the finite angular range of the memory effect limits the field of view. Here, we demonstrate experimentally that selective coupling of incident light into a high-transmission channel increases the angular memory-effect range. This enhancement is attributed to the robustness of the high-transmission channels against perturbations such as sample tilt or wave front tilt. Our work shows that the high-transmission channels provide an enhanced field of view for memory-effect-based imaging through diffusive media.

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Tests Of General Relativity With The Binary Black Hole Signals From The Ligo-Virgo Catalog Gwtc-1, B. P. Abbott, R. Abbott, T. D. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Nov 2019

Tests Of General Relativity With The Binary Black Hole Signals From The Ligo-Virgo Catalog Gwtc-1, B. P. Abbott, R. Abbott, T. D. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The detection of gravitational waves by Advanced LIGO and Advanced Virgo provides an opportunity to test general relativity in a regime that is inaccessible to traditional astronomical observations and laboratory tests. We present four tests of the consistency of the data with binary black hole gravitational waveforms predicted by general relativity. One test subtracts the best-fit waveform from the data and checks the consistency of the residual with detector noise. The second test checks the consistency of the low- and high-frequency parts of the observed signals. The third test checks that phenomenological deviations introduced in the waveform model (including in …

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Jamming Transition In Non-Spherical Particle Systems: Pentagons Versus Disks, Y. Zhao, J. Barés, H. Zheng, Cacey Stevens Bester, Y. Xu, J. E. S. Socolar, R. P. Behringer Nov 2019

Jamming Transition In Non-Spherical Particle Systems: Pentagons Versus Disks, Y. Zhao, J. Barés, H. Zheng, Cacey Stevens Bester, Y. Xu, J. E. S. Socolar, R. P. Behringer

Physics & Astronomy Faculty Works

We investigate the jamming transition in a quasi-2D granular material composed of regular pentagons or disks subjected to quasistatic uniaxial compression. We report six major findings based on experiments with monodisperse photoelastic particles with static friction coefficient μ≈1. (1) For both pentagons and disks, the onset of rigidity occurs when the average coordination number of non-rattlers, Znr, reaches 3, and the dependence of Znr on the packing fraction ϕ changes again when Znr reaches 4. (2) Though the packing fractions ϕc1 and ϕc2 at these transitions differ from run to run, for both shapes the data from all runs with …

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Characterization And Longitudinal Assessment Of Daily Quality Assurance For An Mr-Guided Radiotherapy (Mrgrt) Linac, Kathryn Mittauer Nov 2019

Characterization And Longitudinal Assessment Of Daily Quality Assurance For An Mr-Guided Radiotherapy (Mrgrt) Linac, Kathryn Mittauer

All Publications

No abstract provided.

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Electroosmotic Flow Of Viscoelastic Fluid In A Nanochannel Connecting Two Reservoirs, Lanju Mei, Shizhi Qian Nov 2019

Electroosmotic Flow Of Viscoelastic Fluid In A Nanochannel Connecting Two Reservoirs, Lanju Mei, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

Electroosmotic flow (EOF) of viscoelastic fluid with Linear Phan-Thien–Tanner (LPTT) constitutive model in a nanochannel connecting two reservoirs is numerically studied. For the first time, the influence of viscoelasticity on the EOF and the ionic conductance in the micro-nanofluidic interconnect system, with consideration of the electrical double layers (EDLs), is investigated. Regardless of the bulk salt concentration, significant enhancement of the flow rate is observed for viscoelastic fluid compared to the Newtonian fluid, due to the shear thinning effect. An increase in the ionic conductance of the nanochannel occurs for the viscoelastic fluid. The enhancement of the ionic conductance is …

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From Cymatics To Sound Therapy: Their Role In Spirituality And Consciousness Research, Victor Christianto, Kasan Susilo, Florentin Smarandache Oct 2019

From Cymatics To Sound Therapy: Their Role In Spirituality And Consciousness Research, Victor Christianto, Kasan Susilo, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

Sound is one of the types of waves that can be felt by the sense of hearing (ears). In physics, the definition of sound is something that is produced from objects that vibrate. Objects that produce sound are called sound sources. The sound source that vibrates will vibrate the molecules into the air around it. Sound is mechanical compression or longitudinal waves that propagate through the medium. This medium or intermediate agent can be liquid, solid, gas. So, sound waves can propagate for example in water, coal, or air. Most sounds are a combination of various vibratory signals composed of …

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Extreme Dynamics Of Nanomaterials Under High-Rate Mechanical Stimuli, Wanting Xie Oct 2019

Extreme Dynamics Of Nanomaterials Under High-Rate Mechanical Stimuli, Wanting Xie

Doctoral Dissertations

Nanomaterials demonstrate novel mechanical properties attributed to the extremely large interfacial area. At quasi-static rates, the interfacial interactions are crucial in mechanical behaviors, however, materials under extreme mechanical stimuli are rarely studied at nanoscale. With an advanced laser-induced projectile impact test, we perform supersonic impact of micro-projectiles on polymer films, multilayer graphene, carbon- based nanocomposites membranes as well as individual micro-fibers, to study the interface interactions in the high-rate regime, and develop a simplified model to characterize the ballistic performance of materials.

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Residual Stress Models For Large Eddy Simulation Of Stratified Turbulent Flows, Felipe Augusto Ventura De Bragança Alves Oct 2019

Residual Stress Models For Large Eddy Simulation Of Stratified Turbulent Flows, Felipe Augusto Ventura De Bragança Alves

Doctoral Dissertations

The residual stresses and scalar fluxes are required to close the momentum and scalar transport equations in simulations of turbulence that are not fully resolved in space. In stratified turbulence, the stress and fluxes are statistically anisotropic unless the smallest resolved length scale is smaller than the Ozmidov scale and the buoyancy Reynolds number is sufficiently high for there to exist a range of scales that is statistically isotropic. In this work, a tensorial basis set is derived analytically that potentially contains sufficient information about the anisotropic interaction between resolved and residual scales. The residual stress tensor is evaluated by …

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Characterization Of The Anomalous Ph Of Aqueous Nanoemulsions, Kieran P. Ramos Oct 2019

Characterization Of The Anomalous Ph Of Aqueous Nanoemulsions, Kieran P. Ramos

Doctoral Dissertations

Aqueous water-in-oil nanoemulsions have emerged as a versatile tool for use in microfluidics, drug delivery, single-molecule measurements, and other research. Nanoemulsions are often prepared with perfluorocarbons which are remarkably biocompatbile due to their stability, low surface tension, lipophobicity, and hydrophobicity. Therefore it is often assumed that droplet contents are unperturbed by the perfluorinated surface. However, in microemulsions, which are similar to nanoemulsions, it is known that either the pH of the aqueous phase or the ionization constants of encapsulated molecules are different from bulk solution. There is also recent evidence of low pH in perfluorinated aqueous nanoemulsions. The current underlying …

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