Other Physics Commons^™

Helioseismic Diagnostics Of Active Regions And Their Magnetic Fields, John T. Stefan

Dissertations

While two and a half decades of nearly constant observation by the Solar and Heliospheric Observatory (SOHO) and the Solar Dynamics Observatory (SDO) spacecraft have yielded key insights into the structure and dynamics of active regions, it is still unclear if active regions can be identified before emerging on the solar surface and, once emerged, whether the subsurface structure of an active region’s magnetic field can be measured. Regarding the dynamical processes associated with active regions, the height and mechanism of sunquake excitation remains poorly understood. To answer these questions, a comprehensive survey of active region magnetic fields and their …

Interactions Of Amyloid Peptides With Lipid Membranes, Yanxing Yang

Dissertations

The aggregation of amyloid proteins into fibrils is a hallmark of several diseases including Alzheimer’s (AD), Parkinson’s, and Type II diabetes. This aggregation process involves the formation of small size oligomers preceding the formation of insoluble fibrils. Recent studies have shown that these oligomers are more likely to be responsible for cell toxicity than fibrils. A possible mechanism of toxicity involves the interaction of oligomers with the cell membrane compromising its integrity. In particular, oligomers may form pore-like structures in the cell membrane affecting its permeability or they may induce lipid loss via a detergent-like effect. This dissertation aims to …

A Study Of The Structural, Optical, And Ferroelectric Characteristics Of Pb-Ge-Te Nanocrystalline Alloys As Potential Candidates For Memory Devices And Near-Infrared (Nir) Applications, Asmaa Elkhodary, Salah M. Elsheikh, Hosny A. Omar, Manal A. Mahdy, Iman A. Mahdy

Basic Science Engineering

Pb_50-xGe_xTe₅₀ (x = 15, 20, 25, 30 at. %) nanocrystalline bulk alloys were prepared using solid-state direct reaction. X-ray diffraction and high-resolution transmission electron microscopy (HR-TEM) analysis of the reference structure (Ge = 15 at.%) revealed a slightly distorted cubic structure, with a lattice parameter of 6.43 Å and an inter-axis unit cell angle of 88.69◦. Atomic force images’ analysis and histograms displayed a homogenous particle size distribution in the nanoscale for all samples. Density measurements showed a gradual decrease from 7.89 to 6.98 g/cm3 with increasing Ge content in agreement with the calculated values. …

Probability Distributions Of The Scalar Potential, Candace Mathews

Legacy Theses & Dissertations (2009 - 2024)

In the study of cosmological inflation, string theory and supersymmetry have motivated a wide range of possible inflationary models. These models can be parameterized by a scalar potential V, which is a function of N scalar fields, and determines cosmological parameters such as the vacuum stability and energy density. In principle, we can determine V through high energy physics, such as string theory. In practice, though we may not know the details of V we might have clues about a distribution of plausible V’s, which we can build statistics on to further analyze. The purpose of this thesis defense is …

Denoising And Deconvolving Sperm Whale Data In The Northern Gulf Of Mexico Using Fourier And Wavelet Techniques, Kendal Mccain Leftwich

LSU New Orleans Theses and Dissertations

The use of underwater acoustics can be an important component in obtaining information from the oceans of the world. It is desirable (but difficult) to compile an acoustic catalog of sounds emitted by various underwater objects to complement optical catalogs. For example, the current visual catalog for whale tail flukes of large marine mammals (whales) can identify even individual whales from their individual fluke characteristics. However, since sperm whales, Physeter microcephalus, do not fluke up when they dive, they cannot be identified in this manner. A corresponding acoustic catalog for sperm whale clicks could be compiled to identify individual …

A Mechanically Intelligent Hosing-Drone, Blake Hament

UNLV Theses, Dissertations, Professional Papers, and Capstones

This manuscript presents a ”mechanically intelligent” approach to designing a Hosing-Drone for heavy-duty pressure washing. Spraying a hose creates strong reaction forces and torques. Previously demonstrated spraying robots are over-engineered to be very massive with huge inertias. These high inertias ”wash out” the reaction from the spraying. In the proposed approach, the contributions from all observable fluid dynamics, fluid structure interactions, and aerodynamics are studied individually and for the coupled system. Experimental data is collected and fit to dynamic models. These models are used to design a smaller, lighter, more agile vehicle than has been previously demonstrated. An impedance controller …

Global Sporadic-E Occurrence Rate Climatology Using Gps Radio Occultation And Ionosonde Data, Travis J. Hodos, Omar A. Nava, Eugene V. Dao, Daniel J. Emmons

Faculty Publications

An updated global climatology of blanketing sporadic E (Es) is developed from a combined data set of Global Positioning System (GPS) radio occultation (RO) and ground-based ionosonde soundings over the period of September 2006–January 2019. A total of 46 sites and 3.2 million total soundings from the Global Ionosphere Radio Observatory network in combination with 3.0 million occultations from the Constellation Observing System for Meteorology, Ionosphere, and Climate constellation are used to calculate global occurrence rates (ORs) for two blanketing frequency thresholds: all blanketing sporadic-E with no limit on intensity (all-Es) and moderate-Es with fbEs …

Quantifying The Magnitude Of To Tal Dose Deviation Caused By Various Sources Of Error Among Iroc Phantom Irradiation Results, Sharbacha S. Edward

Dissertations and Theses (Open Access)

The Imaging and Radiation Oncology Core (IROC) phantoms are used as an end-to-end test of an institution’s radiotherapy processes, and for clinical trial credentialing. Phantoms are treated like patients, and evaluation of the doses received by the thermoluminescent dosimeters (TLDs) inside the phantom, reflects the accuracy with which an institution can image, plan and irradiate a phantom or patient. Recent phantom results show that among the hundreds of various IROC phantoms irradiated annually, 8-17% of institutions fail this test. The purpose of this work was to investigate the various types of errors that may occur during the treatment process and …

Infrastructure Development For Personalized Risk Prediction To Reduce Cardiovascular Disease In Childhood Cancer Survivors, Suman Shrestha

Dissertations and Theses (Open Access)

Although childhood cancer survivors have lengthy life expectancies, they run the risk of experiencing long-term health issues as a result of their treatment. The most frequent non-cancerous cause of morbidity and mortality for these survivors is cardiac disease. Radiation therapy (RT) has been linked in numerous cohort studies to a higher chance of developing a late cardiac disease in these survivors, and this risk rises with higher mean heart doses and increased RT exposure to larger cardiac volumes. Since, the heart is a heterogeneous organ made up of several distinct substructures, RT dose received by the entire heart does not …

Design And Fabrication Of A Low-Cost Dip Coating System For Depositing Homogeneous And Transparent Zno Thin Films, Asaad S. Yasir, Basheer M. Hussein, Ammar S. Hameed, Noor J. Ridha, Firas K. Mohamad Alosfur, Khawla J. Tahir, Rajaa A. Madlol

Al-Bahir

ZnO has a resistivity of up to 104 Ω cm-1 in most cases. Nevertheless, by increasing the layer thickness, the resistivity decreases as well, resulting in greater current transport. The dip coating system was developed to prepare the ultra-thin film, it relied on a controller, stepper motor and some low-cost recycled materials. Thin films of ZnO were successfully deposited on indium tin oxide substrates. The effects of the dipping cycles were investigated. Dipping processes were applied several times (1, 2, and 3) for the same concentrations (0.1) M to obtain homogeneous thin films. X-ray diffraction showed that the structure of …

An Interactive Simulation And Visualization Tool For Conventional And Aberration-Corrected Transmission Electron Microscopy, Xingzhong Li

Nebraska Center for Materials and Nanoscience: Faculty Publications

Contrast transfer function (CTF) is a vital function in transmission electron microscopy (TEM). It expresses to what extent amplitudes converted from the phase changes of the diffracted waves contribute to the TEM image, including the effects of lens aberrations. Simulation is very helpful to understand the application of the function thoroughly. In this work, we develop the CTFscope as a component in the Landyne software suite, to calculate the CTF with temporal and spatial dumping envelopes for conventional TEM and to extend it to various aberrations (up to fifth order) for aberration-corrected (AC)- TEM. It also includes effects on the …

Thermal Degradation Of Erythritol, Sudheendra Gamoji

Physics

The Insulated Solar Electric Cooker (ISEC) is a double walled Aluminum pot with a resistive heater directly connected to a solar panel whose goal is to create and disseminate cheap solar cookers in rural areas that primarily rely on biomass for cooking. Phase Change Materials (PCMs) like Erythritol, a sugar substitute, take a tremendous amount of energy to melt, and when they solidify they release the energy. Through the use of PCMs, the ISECs will produce enough heat to cook food even after the sun sets. However, PCMs like Erythritol degrade over repeated heat exposure, so the purpose of this …

Orbit Propagation And Determination Algorithms For Satellite Ground Stations, Shamma Esmaeel Jamali

Theses

The satellite orbital parameters are essential for satellite operations. With these parameters, it is possible to estimate the satellite position in the recent past and near future, which is essential to effectively plan satellite operations and associate satellite telemetry with geographical locations.
However, for small or medium satellite operators who do not possess the infrastructure required to track their satellites, the problem of determining the satellite orbit is problematic. To access the orbit for their satellites, these organizations have to rely on third parties such as Celestrak. These entities provide the service free of charge but do not provide orbital …

Electro-Optical Sensors For Atmospheric Turbulence Strength Characterization With Embedded Edge Ai Processing Of Scintillation Patterns, Ernst Polnau, Don L. N. Hettiarachchi, Mikhail A. Vorontsov

Electro-Optics and Photonics Faculty Publications

This study introduces electro-optical (EO) sensors (TurbNet sensors) that utilize a remote laser beacon (either coherent or incoherent) and an optical receiver with CCD camera and embedded edge AI computer (Jetson Xavier Nx) for in situ evaluation of the path-averaged atmospheric turbulence refractive index structure parameter C-n(2) at a high temporal rate. Evaluation of C-n(2) values was performed using deep neural network (DNN)-based real-time processing of short-exposure laser-beacon light intensity scintillation patterns (images) captured by a TurbNet sensor optical receiver. Several pre-trained DNN models were loaded onto the AI computer and used for TurbNet sensor performance evaluation in a set …

Comparative Photovoltaics Of P3ht:N2200 And P3ht: Small-Gap Fullerene Ethyl-Nipecotate Bulk Heterojunction Structures, Md. Nasir Uddin, Rafiqul Islam, Muhibur Rahman, Nazia Chawdhury

Makara Journal of Science

This work deals with the study on the optical absorption and photoluminescence spectra of a p-type organic semiconducting polymer, regioregular poly 3-hexylthiophene-2,5-diyl (P3HT) and the absorption spectra of an n-type fullerene-based small-gap fullerene-ethyl nipecotate (Fullerene-EN) and a non-fullerene-based polynaphthalene bithiophene (N2200) semiconducting materials. The band gap of P3HT, N2200, and small-gap fullerene-ethyl nipecotate are 2.42, 1.65, and 1.51 eV, respectively, calculated from experimental results through the Tauc equation. Active layers with blends of P3HT and small-gap fullerene-ethyl nipecotate and P3HT and N2200 have been used to fabricate bulk heterojunction (BHJ) structures. The P3HT:N2200 BHJ structure follows the current density versus …

Classification Of Pixel Tracks To Improve Track Reconstruction From Proton-Proton Collisions, Kebur Fantahun, Jobin Joseph, Halle Purdom, Nibhrat Lohia

SMU Data Science Review

In this paper, machine learning techniques are used to reconstruct particle collision pathways. CERN (Conseil européen pour la recherche nucléaire) uses a massive underground particle collider, called the Large Hadron Collider or LHC, to produce particle collisions at extremely high speeds. There are several layers of detectors in the collider that track the pathways of particles as they collide. The data produced from collisions contains an extraneous amount of background noise, i.e., decays from known particle collisions produce fake signal. Particularly, in the first layer of the detector, the pixel tracker, there is an overwhelming amount of background noise that …

Quantum Error Detection Without Using Ancilla Qubits, Nicolas Guerrero

Theses and Dissertations

Quantum computers are beset by errors from a variety of sources. Although quantum error correction and detection codes have been developed since the 1990s, these codes require mid-circuit measurements in order to operate. In order to avoid these measurements we have developed a new error detection code that only requires state collapses at the end of the circuit, which we call no ancilla error detection (NAED). We investigate some of the mathematics behind NAED such as which codes can detect which errors. We then run NAED on three separate types of circuits: Greenberger–Horne–Zeilinger circuits, phase dependent circuits, and a quantum …

Polarization Switching In Gold Nanostructure Array, Harrison Knox

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Nmr Characterization Of Novel Materials For Battery Electrolyte Applications, Sahana Bhattacharyya

Dissertations, Theses, and Capstone Projects

The extensive application of renewable and non-renewable energy storage devices in commercial products and services and the global warming have created significant motivations to accelerate research in battery technology. In addition, the risk factors generated by the high heat generation and flammability of the batteries are being addressed by inventing new renewable or non-renewable energy resources that do not release greenhouse gases into the atmosphere. This thesis discusses the applications of Nuclear Magnetic Resonance (NMR) Spectroscopy in characterizing and understanding novel battery materials as potential battery electrolytes. Works discussed include: the variable temperature characterization of water-based solid polymer electrolyte for …

Topological Shadow Of Higher-Order Topological Phases And Non-Hermitian Phases Protected By Generalized Rotational Symmetry, Kai Chen

Dissertations, Theses, and Capstone Projects

Topological phenomena in condensed matter physics have been investigated intensively in the past decades since the discovery of the integer quantum Hall effect (IQHE). For the IQHE, the energy band can be characterized by its topological invariants (Chern number or TKNN invariant), which relates to the quantized Hall conductance directly. Later, this expression was recognized as the first Chern class of a U(1) principal fiber bundle on a torus, where the fibers and torus correspond respectively to the magnetic Bloch waves and the magnetic Brillouin zone. And then, the discoveries of time-reversal symmetric topological insulators in two and three dimensions …

Diagnostics Of Energy Release In Solar Flares With Radio Dynamic Imaging Spectroscopy, Yingjie Luo

Dissertations

Studies of the magnetic energy release and conversion process lie at the core of solar flare physics. Radio observations serve as a unique diagnostic method. In this dissertation, taking advantage of broadband radio dynamic imaging spectroscopy observations made by the Karl G. Jansky Very Large Array (VLA), studies are carried out on the flare energy release processes using different types of radio emissions.

The VLA is a general-purpose radio observatory located in New Mexico, which provides high-quality radio dynamic imaging spectroscopic observations with an ultra-fast time cadence. In the first study, stochastic decimetric radio spike bursts are observed by the …

Perovskite Solar Cells, Liqiu Zheng Dr., Tyler Hurst, Zhongrui Li

Georgia Journal of Science

The semiconductor perovskite CsPbBr₂I was doped with Mn²⁺ to modulate its optical and photovoltaic performance. The Mn²⁺-doped CsPb_0.9Mn_0.1Br₂I exhibited improved crystalline quality. Ultraviolet and visible spectroscopy of Mn²⁺-doped CsPb_0.9Mn_0.1Br₂I revealed enhanced absorption capacity. Although the efficiency was not as good as desired, the enhanced light absorption of CsPb_0.9Mn_0.1Br₂I still boosted the photovoltaic performance when it was utilized as a light absorber in perovskite solar cells, along with a low-cost carbon electrode. Compared with its counterpart …

Developing A Software Defined Radio Based Faraday Receiver, Alvaro J. Guerra

All Theses

The ionosphere can be approximated as a magnetized plasma. This results in wave- particle interactions driving a large quantity of ionospheric phenomena. To understand these phenomena, it is important to quantify and measure certain key plasma parameters. One such parameter is electron density. The Faraday Experiment was developed for the purpose of measuring electron density in the D-region of the ionosphere. This experiment was made popular by Martin Friedrich in the 1970s and is currently one of the only ways to provide high resolution measurements of electron density in the D-region without actively disturbing the surrounding plasma. This thesis aims …

A Comparison Of Uniaxial Compressive Response And Inelastic Deformation Mechanisms In Freeze Cast Alumina-Epoxy Composites Without And With Rigid Confinement, Tareq Aljuhari

Mechanical & Aerospace Engineering Theses & Dissertations

Cellular ceramics have an array of improved mechanical properties that make them incredibly desired for different applications such as armor systems, aircraft structures, automobiles bumpers, and biomedical implants. It is also desirable that porous architecture could be shaped into bulk complicated shapes and easy to scale-up with low manufacturing cost. Despite several efficient techniques to fabricate cellular ceramics, some limitations are preventing us from meeting the high demand of the after mentioned applications. For that, freeze casting, also called ice-templating, is technique of solidifying an aqueous ceramic suspension under the effect of unidirectional temperature gradient. In this study, Ice-templated porous …

Calculational Methods In Conformal Field Theory, Thomas Andrew Vandermeulen

Legacy Theses & Dissertations (2009 - 2024)

We examine conformal field theories and their gaugings (orbifolds), first on the torus and then on surfaces of higher genus. Specific attention is paid to performing explicit calculations, to which end we introduce a number of specialized formalisms. Namely, the technology of flavored partition functions allows for a general treatment of orbifolds in theories with conserved currents, and Arakelov geometry facilitates the derivation of novel expressions for geometric quantities appearing commonly on higher genus worldsheets. Ultimately, we leverage the resulting expressions in the calculation of correlation functions via degeneration of Riemann surfaces.

Weakness Of Weak Values: Incompatibility Of Anomalous Pulse-Spectrum Amplification And Optical Frequency Combs, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We probe the use of optical frequency combs to place lower bounds on anomalous amplification of a weak-value-measured pulse delay, potentially reaching a theoretical temporal resolution of better than 10⁻³⁴ s. Owing to the interferometric behavior of weak values, we show that anomalous weak value amplification of a time delay is not equivalent to a temporal linear phase ramp. We show that the anomalous weak value is a rearrangement of amplitudes that generates an apparent shift that can be measured in direct detection, but does not change the actual frequency offset of a spectral distribution measurable in coherent detection. …

Ultra-High Carrier Mobilities In Ferroelectric Domain Wall Corbino Cones At Room Temperature, Conor J. Mccluskey, Matthew G. Colbear, James P.V. Mcconville, Shane J. Mccartan, Jesi R. Maguire, Michele Conroy, Kalani Moore, Alan Harvey, Felix Trier, Ursel Bangert, Alexei Gruverman, Manuel Bibes, Amit Kumar, Raymong G.P. Mcquaid, J. Marty Gregg

Alexei Gruverman Publications

Recently, electrically conducting heterointerfaces between dissimilar band-insulators (such as lanthanum aluminate and strontium titanate) have attracted considerable research interest. Charge transport has been thoroughly explored and fundamental aspects of conduction firmly established. Perhaps surprisingly, similar insights into conceptually much simpler conducting homointerfaces, such as the domain walls that separate regions of different orientations of electrical polarisation within the same ferroelectric band-insulator, are not nearly so well-developed. Addressing this disparity, we herein report magnetoresistance in approximately conical 180° charged domain walls, which occur in partially switched ferroelectric thin film single crystal lithium niobate. This system is ideal for such measurements: firstly, …

Hybrid Modulated-Phase-Grating For Phase Contrast X-Ray For A Varying Fringe Period Clinical Interferometry System, Elizabeth Jeong Park

LSU Master's Theses

Phase contrast x-rays are of use due to the range of imaging they can provide. Not only are they useful for attenuation they also can provide phase and small angle scatter X-ray (SAXS) information simultaneously which adds additional contrast and information to the original attention image. In prior work, a phase contrast system with Modulated Phase Grating was shown to eliminate the need for analyzer in standard Talbot Lau Xray Interferometers (TLXI). The system is clinically compatible in footprint due to its length being limited to

Accident Simulation Study For Nuclear Power Plants Impacting Louisiana, Michael D. Mcmahon

LSU Master's Theses

INTRODUCTION: Louisiana has aligned its radiological emergency program with the 2017 Environmental Protection Agency Protective Action Guides Manual, but has added a child thyroid dose evacuation threshold in lieu of distributing Potassium Iodide to the public. The nuclear power plants will continue to align with the 1992 manual for the foreseeable future, so that under some accident scenarios the state recommendations will differ from those of the utility.

OBJECTIVE: The objective of this study is to predict what accident and weather conditions will lead to a differing set of recommendations.

METHODS: More than 1000 simulations were performed of low-filtration nuclear …

Shadows Of A Schwarzschild Black Hole Surrounded By A Spherically Symmetric Dark Matter, Ahmad Ibrahim

Theses and Dissertations

In this thesis, using general relativity, the null geodesics and black hole shadow of a spherically symmetric configuration of a black hole (surrounded by a dark matter shell) are studied. First, the standard

results of the photon sphere of Schwarzschild de-Sitter black hole is revisited and analyzed more carefully. Secondly, using an ansatz (piecewise metric function) commonly used in the literature to describe the mass distribution of the spherically symmetric black hole - dark matter configuration, the null geodesics through vacuum and dark matter are analyzed. Assuming an observer located at a finite distance from the black hole outside the …