Digital Commons Network^™

Computational Aerothermodynamic Analysis Of Satellite Trans-Atmospheric Skip Entry Survivability, John J. Runco

Theses and Dissertations

Computational aerothermodynamic analysis is presented for a spacecraft in low Earth orbit performing an atmospheric skip entry maneuver. Typically, atmospheric reentry is a terminal operation signaling mission end-of-life and, in some instances, executed for spacecraft disposal. A variation on reentry – skip entry – is an aeroassisted trans-atmospheric maneuver in which a spacecraft utilizes the effects of aerodynamic drag in order to reduce energy prior to a terminal entry, pinpoint a targeted entry, or change orbital elements such as inclination. Spacecraft performing a skip entry enable new modes of maneuver to enhance operations in nominal or possibly contested mission environments. …

Sheet Velocity Measurements Using Laser Absorption Spectroscopy In A Xenon Hall Effect Thruster Plume, Avery W. Leonard

Theses and Dissertations

A new laser absorption spectroscopy (LAS) velocimetry system, designed to obtain 2D planar velocity fields for ionized Xenon in the plume of a Hall effect thruster by probing the transition of Xe II at 834.72 nm, was implemented at the Air Force Institute of Technology (AFIT) Space Propulsion Analysis and System Simulator (SPASS) Lab vacuum chamber. A single horizontal laser sheet was used to probe singly-ionized Xenon in the plume of a Busek BHT-600 Hall thruster and obtain a histogram of estimated axial velocity, to validate the system. Similar velocities to those obtained by an earlier intrusive characterization of the …

Investigation Of Endwall Vortex Manipulation In High Lift Turbines Caused By Active Endwall Forcing, Horatio J. Babcock

Theses and Dissertations

With the increased demand for lighter, more fuel efficient and smaller gas turbine engines, the impetus to reduce the weight and size of the turbine has become apparent. One approach to reduce this weight is to reduce the number of blades in the turbine. However, to maintain power output, each blade must be capable of supporting a greater amount of lift. While several high-lift turbine profiles have been detailed in literature, most of these profiles have increased endwall losses, despite their desirable mid-span characteristics. To mitigate this endwall loss, a number of active and passive flow approaches have been studied …

A Second Galaxy Missing Dark Matter In The Ngc 1052, Pieter Van Dokkum, Shany Danieli, Roberto Abraham, Charlie Conroy, Aaron Romanowsky

Faculty Publications

The ultra-diffuse galaxy NGC1052-DF2 has a very low velocity dispersion, indicating that it has little or no dark matter. Here we report the discovery of a second galaxy in this class, residing in the same group. NGC1052-DF4 closely resembles NGC1052-DF2 in terms of its size, surface brightness, and morphology; has a similar distance of Dsbf =  19.9 2.8 Mpc; and also has a population of luminous globular clusters extending out to 7 kpc from the center of the galaxy. Accurate radial velocities of the diffuse galaxy light and seven of the globular clusters were obtained with the Low Resolution …

Search For Low-Mass Dark Matter With Cdmslite Using A Profile Likelihood Fit, R. Agnese, T. Aralis, T. Aramaki, I. J. Arnquist, E. Azadbakht, W. Baker, S. Banik, D. Barker, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y.-Y. Chang, J. Cooley, B. Cornell, P. Cushman, F. De Brienne, T. Doughty, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, H. R. Harris, N. Herbert, Z. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, R. E. Lawrence, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. Miller, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, J. Nelson, H. Neog, J. L. Orrell, S. M. Oser, W. A. Page, R. Partridge, M. Pepin, F. Ponce, S. Poudel, M. Pyle, H. Qiu, W. Rau, A. Reisetter, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, A. Scarff, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, C. Stanford, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, S. L. Watkins, J. S. Wilson, M. J. Wilson, J. Winchell, D. H. Wright, S. Yellin, Betty A. Young, X. Zhang, X. Zhao

Physics

The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) searches for interactions between dark matter particles and germanium nuclei in cryogenic detectors. The experiment has achieved a low energy threshold with improved sensitivity to low-mass (/c²) dark matter particles. We present an analysis of the final CDMSlite data set, taken with a different detector than was used for the two previous CDMSlite data sets. This analysis includes a data "salting" method to protect against bias, improved noise discrimination, background modeling, and the use of profile likelihood methods to search for a dark matter signal in the presence …

Determination Of Conversion Factors For Various Calibration Geometries Using Barium-133 In A Silver Zeolite Cartridge, Amin Hamideh

LSU Master's Theses

Iodine-131 (I-131) is a major fission product among other radionuclides released during a nuclear incident. This radioiodine has a half-life of 8.02 days and the primary organ of uptake through ingestion or inhalation is the thyroid gland. For these reasons, nuclear power plants must routinely monitor I-131 through air sampling. Currently, there are two adsorbing media to collect I-131: activated charcoal and silver zeolite cartridges. Silver zeolite cartridges are generally used during a post nuclear incident due to its affinity for iodine while not adsorbing noble gases such as krypton-85 and xenon-135. After an air sample is taken from a …

Analysis Of Dynamic Behaviour Of A Tensioned Carbon Nanotube In Thermal And Pressurized Environments, Ahmed Yinusa, Gbeminiyi Sobamowo

Karbala International Journal of Modern Science

In this paper, the dynamic behaviour of a tensioned single-walled carbon nanotubes (SWCNT) in thermal and pressurized environments is investigated analytically. With the applications of Bernoulli-Euler and thermal elasticity mechanics theories, the governing equation of motion are developed and solved using Laplace and Fourier transforms. The results of the close form solution in this work are in excellent agreements with past results in literature. From the parametric studies, it is established that as the magnitude of the pressure distribution at the surface increases, the deflection associated with the nanotube increases at any mode of vibration. However, a corresponding increase in …

Influence Of Strain And Chemical Substitution On The Magnetic Anisotropy Of Antiferromagnetic Cr2O3: An Ab-Initio Study, Sai Mu, Kirill D. Belashchenko

Department of Physics and Astronomy: Faculty Publications

The influence of the mechanical strain and chemical substitution on the magnetic anisotropy energy (MAE) of Cr₂O₃ is studied using first-principles calculations. Dzyaloshinskii-Moriya interaction contributes substantially to MAE by inducing spin canting when the antiferromagnetic order parameter is not aligned with the hexagonal axis. Nearly cubic crystal field results in a very small MAE in pure Cr₂O₃ at zero strain, which is incorrectly predicted to be negative (in-plane) on account of spin canting. The MAE is strongly modified by epitaxial strain, which tunes the crystal-field splitting of the t_2g triplet. The contribution from …

Polymer Gels With Tunable Ionic Seebeck Coefficient For Ultra-Sensitive Printed Thermopiles, Dan Zhao, Anna Martinelli, Andreas Willfahrt, Thomas Fischer, Diana Bernin, Zia Ullah Khan, Maryam Shahi, Joseph W. Brill, Magnus P. Jonsson, Simone Fabiano, Xavier Crispin

Physics and Astronomy Faculty Publications

Measuring temperature and heat flux is important for regulating any physical, chemical, and biological processes. Traditional thermopiles can provide accurate and stable temperature reading but they are based on brittle inorganic materials with low Seebeck coefficient, and are difficult to manufacture over large areas. Recently, polymer electrolytes have been proposed for thermoelectric applications because of their giant ionic Seebeck coefficient, high flexibility and ease of manufacturing. However, the materials reported to date have positive Seebeck coefficients, hampering the design of ultra-sensitive ionic thermopiles. Here we report an “ambipolar” ionic polymer gel with giant negative ionic Seebeck coefficient. The latter can …

Three-Dimensional Time-Resolved Trajectories From Laboratory Insect Swarms, Michael Sinhuber, Kasper Van Der Vaart, Rui Ni, James G. Puckett, Douglas H. Kelley, Nicholas T. Ouellette

Physics and Astronomy Faculty Publications

Aggregations of animals display complex and dynamic behaviour, both at the individual level and on the level of the group as a whole. Often, this behaviour is collective, so that the group exhibits properties that are distinct from those of the individuals. In insect swarms, the motion of individuals is typically convoluted, and swarms display neither net polarization nor correlation. The swarms themselves, however, remain nearly stationary and maintain their cohesion even in noisy natural environments. This behaviour stands in contrast with other forms of collective animal behaviour, such as flocking, schooling, or herding, where the motion of individuals is …

A State-Of-The-Art Survey On Deep Learning Theory And Architectures, Md Zahangir Alom, Tarek M. Taha, Christopher Yakopcic, Stefan Westberg, Paheding Sidike, Mst Shamima Nasrin, Mahmudul Hasan, Brian C. Van Essen, Abdul A. S. Awwal, Vijayan K. Asari

Electrical and Computer Engineering Faculty Publications

In recent years, deep learning has garnered tremendous success in a variety of application domains. This new field of machine learning has been growing rapidly and has been applied to most traditional application domains, as well as some new areas that present more opportunities. Different methods have been proposed based on different categories of learning, including supervised, semi-supervised, and un-supervised learning. Experimental results show state-of-the-art performance using deep learning when compared to traditional machine learning approaches in the fields of image processing, computer vision, speech recognition, machine translation, art, medical imaging, medical information processing, robotics and control, bioinformatics, natural language …

Bounds On Extra Dimensions From Micro Black Holes In The Context Of The Metastable Higgs Vacuum, Katherine J. Mack, Robert A. Mcnees Iv

Physics: Faculty Publications and Other Works

We estimate the rate at which collisions between ultrahigh-energy cosmic rays can form small black holes in models with extra dimensions. If recent conjectures about false vacuum decay catalyzed by black hole evaporation apply, the lack of vacuum decay events in our past light cone may place new bounds on the black hole formation rate and thus on the fundamental scale of gravity in these models. For theories with fundamental scale E∗ above the Higgs instability scale of the Standard Model, we find a lower bound on E∗ that is within about an order of magnitude of the energy where …

Phase Estimation In Linear And Nonlinear Interferometers, Sushovit Adhikari

LSU Doctoral Dissertations

Phase estimation has a wide range of applications. Over the years, several strategies have been studied to improve precision in phase estimation. These strategies include using exotic quantum states to quantum detection schemes. This dissertation summarizes my effort in improving the precision of phase estimation with a linear and nonlinear interferometer.

Chapter 1 introduces quantum optics and quantum metrology. I introduce all relevant quantum states of light used. We also look into tools and terminologies of quantum metrology such as Fisher information, shot-noise limit, Heisenberg limit, etc., along with examples of phase estimation with a Mach-Zehnder interferometer.

In Chapter 2, …

The Limited Reign Of Saturn's Rings, Laurence A. Marschall

Physics and Astronomy Faculty Publications

Saturn’s rings—stretching tens of thousands of miles above its equator but no more than a few hundred yards thick—mark an ancient debris field of orbiting ice shards, the remains of a moon-sized object that strayed too close and was torn to pieces by Saturn’s intense gravitation. Astronomers have debated when the rings formed and how long they will stay in orbit. Recent observations from large, land-based telescopes and orbiting spacecraft reveal that Saturn’s rings are remarkably young and are dissipating at a rapid rate. [excerpt]

Taller In The Saddle: Constraining Cmb Physics Using Saddle Points, Jow L. Dylan, Dagoberto Contreras, Douglas Scott, Emory F. Bunn

Physics Faculty Publications

The statistics of extremal points in the cosmic microwave background (CMB) temperature (hot and cold spots) have been well explored in the literature, and have been used to constrain models of the early Universe. Here, we extend the study of critical points in the CMB to the set that remains after removing extrema, namely the saddle points. We perform stacks of temperature and polarization about temperature saddle points in simulations of the CMB, as well as in data from the Plancksatellite. We then compute the theoretical profile of saddle-point stacks, given the underlying power spectra of the CMB. As an …

Agn Photoionization Of Gas In Companion Galaxies As A Probe Of Agn Radiation In Time And Direction, William C. Keel, Vardha Nicola Bennert, Anna Pancoast, Chelsea E. Harris, Anna Nierenberg, S. Drew Chojnowski, Alexei V. Moiseev, Dmitry V. Oparin, Chris J. Lintott, Kevin Schawinski, Graham Mitchell, Claude Cornen

Physics

We consider active galactic nucleus (AGN) photoionization of gas in companion galaxies (cross-ionization) as a way to sample the intensity of AGN radiation in both direction and time, independent of the gas properties of the AGN host galaxies. From an initial set of 212 AGN+companion systems, identified with the help of Galaxy Zoo participants, we obtained long-slit optical spectra of 32 pairs that were a priori likely to show cross-ionization based on projected separation or angular extent of the companion. From emission-line ratios, 10 of these systems are candidates for cross-ionization, roughly the fraction expected if most AGNs have ionization …

Computational And Experimental Development Of 2d Anisotropic Photonic Crystal Metamaterials, James A. Ethridge

Theses and Dissertations

The future of optical devices involves manipulation of nanoscale structure in order to achieve full control over the properties of the device. In fields as diverse as directed energy, remote sensing, optical communications and optical computing, these devices promise to greatly improve performance and efficiency. To advance this further, novel samples that incorporate both photonic crystal (PhC) structure and metamaterial properties, known as PhC metamaterials, are proposed. These PhC metamaterials allow for complete control over the directionality of the light-matter interaction to serve in these new applications. To develop this technology, first, metamaterials with no PhC structure are fabricated using …

Infrared And Electro-Optical Stereo Vision For Automated Aerial Refueling, William E. Dallmann

Theses and Dissertations

Currently, Unmanned Aerial Vehicles are unsafe to refuel in-flight due to the communication latency between the UAVs ground operator and the UAV. Providing UAVs with an in-flight refueling capability would improve their functionality by extending their flight duration and increasing their flight payload. Our solution to this problem is Automated Aerial Refueling (AAR) using stereo vision from stereo electro-optical and infrared cameras on a refueling tanker. To simulate a refueling scenario, we use ground vehicles to simulate a pseudo tanker and pseudo receiver UAV. Imagery of the receiver is collected by the cameras on the tanker and processed by a …

Search For Narrow Hγ Resonances In Proton-Proton Collisions At √S =13 Tev, A. M. Sirunyan

Department of Physics and Astronomy: Faculty Publications

A search for heavy, narrow resonances decaying to a Higgs boson and a photon (Hγ) has been performed in proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb⁻¹ collected with the CMS detector at the LHC in 2016. Events containing a photon and a Lorentz-boosted hadronically decaying Higgs boson reconstructed as a single, large-radius jet are considered, and the γ + jet invariant mass spectrum is analyzed for the presence of narrow resonances. To increase the sensitivity of the search, events are categorized depending on whether or not …

X-Ray Ptychography On Low-Dimensional Hard-Condensed Matter Materials, Xiaowen Shi, Nicolas Burdet, Bo Chen, Gang Xiong, Robert Streubel, Ross Harder, Ian K. Robinson

Robert Streubel Papers

Tailoring structural, chemical, and electronic (dis-)order in heterogeneous media is one of the transformative opportunities to enable new functionalities and sciences in energy and quantum materials. This endeavor requires elemental, chemical, and magnetic sensitivities at the nano/atomic scale in two- and three-dimensional space. Soft X-ray radiation and hard X-ray radiation provided by synchrotron facilities have emerged as standard characterization probes owing to their inherent element-specificity and high intensity. One of the most promising methods in view of sensitivity and spatial resolution is coherent diffraction imaging, namely, X-ray ptychography, which is envisioned to take on the dominance of electron imaging techniques …

Observation Of The Decay D0 → K− Π + E + E −, J.P. Lees, P. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, D. N. Brown, Yu. G. Kolomensky, M. Fritsch, H. Koch, T. Schroeder, C. Hearty, T. S. Mattison, J. A. Mckenna, R. Y. So, V. E. Blinov, A. R. Buzykaev, V. P. Druzhinin, V. B. Golubev, Milind Purohit, Et. Al.

Faculty Publications

We report the observation of the rare charm decay D⁰ → K−πþeþe−, based on 468 fb−1 of eþe− annihilation data collected at or close to the center-of-mass energy of the ϒð4SÞ resonance with the BABAR detector at the SLAC National Accelerator Laboratory. We find the branching fraction in the invariant mass range 0.675 < m(e⁺e⁻) < 0.875 GeV=c² of the electron-positron pair to be B(D⁰ → K−π⁺e⁺e⁻) = (4.0 ± 0.5 ± 0.2 ± 0.1) × 10⁻⁶, where the first uncertainty is statistical, the second …

Search For A Stable Six-Quark State At Babar, J. P. Lees, V. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, D. N. Brown, Yu G. Kolomensky, M. Fritsch, H. Koch, T. Schroeder, C. Hearty, T. S. Mattison, J. A. Mckenna, R. Y. So, V. E. Blinov, A. R. Buzykaev, V. P. Druzhinin, V. B. Golubev, Milind Purohit

Faculty Publications

Recent investigations have suggested that the six-quark combination uuddss could be a deeply bound state (S) that has eluded detection so far, and a potential dark matter candidate. We report the first search for a stable, doubly strange six-quark state in ϒ → SΛ¯ Λ¯ decays based on a sample of 90 × 10⁶ϒ(2S) and 110 × 10⁶ϒ(3S) decays collected by the BABAR experiment. No signal is observed, and 90% confidence level limits on the combined ϒ(2S; 3S) → SΛ¯ Λ¯ branching fraction in the range (1.2–1.4) × 10⁻⁷ are derived for m …

Electrically Reversible Magnetization At The Antiperovskite/Perovskite Interface, Ding-Fu Shao, Gautam Gurung, Tula R. Paudel, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Using density-functional calculations, we predict the emergence of electrically reversible magnetization at the interface between antiferromagnetic noncollinear antiperovskite GaNMn3 and ferroelectric perovskite BaTiO3. We find that Mn magnetic moments are enhanced and reoriented at the GaNMn3/ATiO3 (001) (A = Sr and Ba) interface, resulting in a sizable net magnetization along the [110] direction. This magnetization is reversed with ferroelectric polarization of BaTiO3 through ∼20◦ rotation of the noncollinear magnetic moments. The effect is driven by ferroelectric modulation of the antiferromagnetic exchange coupling between the interfacial Mn atoms mediated by the Mn-3d orbital population. Our results open opportunities for controlling the …

Near Earth Space Object Detection Using Parallax As Multi-Hypothesis Test Criterion, Joseph C. Tompkins, Stephen C. Cain, David J. Becker

Faculty Publications

The US Strategic Command (USSTRATCOM) operated Space Surveillance Network (SSN) is tasked with Space Situational Awareness (SSA) for the U.S. military. This system is made up of Electro-Optic sensors, such as the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) and RADAR based sensors, such as the Space Fence Gaps. They remain in the tracking of Resident Space Objects (RSO’s) in Geosynchronous Orbits (GEO), due to limitations of SST and GEODSS system implementation. This research explores a reliable, ground-based technique used to quickly determine an RSO’s altitude from a single or limited set of observations. Implementation of such sensors into the SSN …

Probing Spatial Variation Of The Fine-Structure Constant Using The Cmb, Tristan L. Smith, D. Grin, David B. Robinson , '19, Davy Qi , '19

Physics & Astronomy Faculty Works

The fine-structure constant, α, controls the strength of the electromagnetic interaction. There are extensions of the standard model in which α is dynamical on cosmological length and time scales. The physics of the cosmic microwave background (CMB) depends on the value of α. The effects of spatial variation in α on the CMB are similar to those produced by weak lensing: smoothing of the power spectrum, and generation of non-Gaussian features. These would induce a bias to estimates of the weak-lensing potential power spectrum of the CMB. Using this effect, Planck measurements of the temperature and polarization power spectrum, as …

University Physics I: Classical Mechanics, Julio Gea-Banacloche

Open Educational Resources

This is a textbook for the first semester of University Physics for scientists and engineers. It covers classical mechanics, and a brief introduction to thermodynamics. The presentation and approach are similar to Mazur’s “The Principles and Practice of Physics,” in that conservation laws are introduced before forces, and one-dimensional systems thoroughly covered before moving to two dimensions. Although the course is “calculus based,” the book has been written with the understanding that many students may be taking calculus simultaneously as a corequisite, so the use of calculus is relatively sparse.

This revised version (Fall 2019) takes into account a number …

Physics Beyond Catching A Mouse In The Dark: From Big Science To Deep Science, Victor Christianto, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

The Higgs particle has been detected a few years ago, that is what newspapers tell us. For many physicists, the Standard Model of particle physics has accomplished all the jobs. Or to put it simply: The game is over. Is it true? Then some physicists began to ask: can go beyond the Standard Model? Because the supersymmetric extension of the Standard Model has failed. If you feel that theoretical physics is becoming boring, you are not alone. Fortunately, there is good news: a new generation of physicists are doing table-top experiments in their basements. Can we expect new results later?2 …

Saturation And Alternate Pathways In Four-Wave Mixing In Rubidium, Erik Brekke, Noah Swan

Faculty Creative and Scholarly Works

We have examined the frequency spectrum of the blue light generated via four-wave mixing in a rubidium vapor cell inside a ring cavity. At high atomic density and input laser power, two distinct frequency components separated by 116±4  MHz are observed, indicating alternate four-wave mixing channels through the 6p3/2 hyperfine states. The dependence of the generated light on excitation intensity and atomic density are explored, and they indicate that the primary process has saturated. This saturation results when the excitation rate through the 6p state becomes equal to the rate through the 5p state, giving no further gain with atomic …

Simulations Of Microscopic Propulsion Of Soft Elastic Bodies, David Urbanik, Shikhar Man Dwivedi, Colin Denniston

Physics and Astronomy Publications

Using simulations that realistically model both hydrodynamic and elastic behavior, we study the motion of a microscopic, driven elastic sphere immersed in water. We first confirm the “jittery” relaxation recently predicted theoretically for an externally driven elastic sphere. The sphere is then divided in two and each section is driven internally with the two sections 180° out of phase. With periodic and perfectly symmetric driving, the elastic sphere spontaneously breaks symmetry and can attain macroscopic average swimming velocities to the right or left, the direction depending only on the initial state. With asymmetric driving the elastic sphere swims in one …

A Loud Quasi-Periodic Oscillation After A Atar Is Disrupted By A Massive Black Hole, Dheeraj R. Pasham, Ronald A. Remillard, P. Chris Fragile, Alessia Franchini, Nicholas C. Stone, Giuseppe Lodato, Jeroen Homan, Deepto Chakrabarty, Frederick K. Baganoff, James F. Steiner, Eric R. Coughlin, Nishanth R. Pasham

Physics & Astronomy Faculty Research

The tidal forces close to massive black holes can rip apart stars that come too close to them. As the resulting stellar debris spirals toward the black hole, the debris heats up and emits x-rays. We report observations of a stable 131-second x-ray quasi-periodic oscillation from the tidal disruption event ASASSN-14li. Assuming the black hole mass indicated by host galaxy scaling relations, these observations imply that the periodicity originates from close to the event horizon and that the black hole is rapidly spinning. Our findings demonstrate that tidal disruption events can generate quasi-periodic oscillations that encode information about the physical …