Other Astrophysics and Astronomy Commons^™

Phase-Resolved Measurement And Arbitrary Mode Conversion Of Structured Light, Somayeh Ghazanfarpour

Electronic Theses and Dissertations

This dissertation presents a single-shot phase and amplitude retrieval technique based on spatial light modulator (SLM)-based digital holography. The proposed method enables accurate reconstruction of complex optical fields from a single interferogram, reducing sensitivity to environmental fluctuations and improving experimental stability compared to conventional multi-shot approaches. In addition, a programmable arbitrary mode converter is developed using SLM-based wavefront shaping. By introducing controlled astigmatism and engineering the differential Gouy phase between orthogonal components, the system enables flexible transformation between structured light modes, including Hermite–Gaussian and Laguerre–Gaussian beams. Numerical results demonstrate reliable phase recovery and efficient mode conversion, validating the performance of …

Energy Scaling And Frequency Ratios Of Particles And Constants, Alison Christina Menzmer, Donald Chakeres, Vola Andrianarijaona

Campus Research Month

We are exploring quantum aspects of various physical quantities (including Bohr radius, Rydberg constant, Planck time, and Hubble constant) and mass energies of elementary particles (including electron, neutron, and quarks). We express all physical units in an energy equivalence in Hertz, normalized to 1 Hz. Furthermore, the logarithms of these normalized energies are scaled by the logarithm of a chosen particle, which allows the generation of an Arrhenius plot exhibiting numerical structures. Our results presented in this poster show that the proton is a good candidate for an Arrhenius plot with partial fractions (1 + 1/n) and (1 - 1/n).

Dose Characterization Of Galactic Cosmic Rays In The Human Brain: A Phits-Based Study With A Segmented Anatomical Phantom, Shanice N. Manning

LSU Master's Theses

Astronauts aboard the International Space Station (ISS) are chronically exposed to a complex space radiation environment composed of galactic cosmic rays (GCR), solar particles, and Earth's trapped radiation. These high-energy particles interact with spacecraft shielding, producing secondary particles that can penetrate inside and deposit energy in sensitive tissues. Although animal studies have been useful in assessing space radiation risks, anatomical and physiological differences limit their applicability to human anatomy especially neuroanatomy. To address this gap, we developed a computational framework to model radiation dose distribution within the human brain using Monte Carlo simulations in Particle and Heavy Ion Transport code …

The Search For Slow Particles And Magnetic Monopoles With Nova, John Clark

Poster Presentations

Singular magnetic poles, north or south, have been theorized to exist for hundreds of years. In the modern day, the elusive singular magnetic pole still remains undiscovered. The appearance of this particle would help confirm many Grand Unified Theories, GUTs, and revolutionize our understanding of some of the fundamental forces of the universe. Fermilab's NOvA collaboration is working on ways to screen and detect magnetic monopoles and other slow-moving particles coming from outer space alongside their main mission to study neutrinos. The aim of this work is to determine and improve the Far Detector’s efficiency at identifying slow moving particles. …

Computational Modeling Of Astrophysical Systems, Leleya Iris Stallard

Spring Showcase for Research and Creative Inquiry

This research project focuses on the computational modeling of astrophysical systems using Femap with NX Nastran. The goal was to simulate and analyze the vibrational behavior and structural deformation of celestial bodies under different material compositions and collision conditions. Materials such as iron, granite, titanium, and models for white dwarf stars were used to investigate how varying physical properties affect the systems' dynamic responses. Both isotropic and anisotropic models were created to represent realistic astrophysical materials. Through static and modal analyses, the study explored how internal structure and material stiffness influence the reaction of celestial objects to applied forces and …

Three-Dimensional Spreading Of Magnetic Reconnection Between Non-Parallel Flux Ropes With A Guide Field, Regis John

Graduate Theses, Dissertations, and Problem Reports (ETD)

Magnetic reconnection is a fundamental plasma process that facilitates the rapid conversion of magnetic energy into particle acceleration, plasma flows, and heating. It plays a central role in explosive astrophysical events such as solar flares, where vast amounts of magnetic energy are released on short time scales. A key structure in many reconnection sites is the magnetic flux rope, a column of plasma carrying current threaded by helical magnetic fields, which is frequently involved in or generated by reconnection. Understanding how reconnection unfolds in such flux rope systems is critical for interpreting both space weather phenomena and laboratory plasma dynamics. …

The Presence Of Outer Giant Planets And Their Role In Inner Planet Formation With And Without Their Influence, Mateo E. Guerra Toro

Graduate Theses/Dissertations

We performed dynamical simulations of the giant impact phase of planet formation to investigate the formation of inner terrestrial planets under the influence of 4 solar system-like outer giant planets. We developed a new code using the N-body simulation suite REBOUND and REBOUNDx (Rein et al. (2019) and Tamayo et al. (2019)) to simulate 2 stages of planetary formation: a residual gaseous protoplanetary disk phase and subsequent dynamical evolution after the disk photoevaporates. The initial conditions for the inner planetary embryos were taken by Morrison et al. (2020) based on a range of solid surface densities that produced Super-Earth terrestrial …

Studying The Impact Of The Geospace Environment On Solar Lithosphere Coupling And Earthquake Activity, Dimitar Ouzounov, Galina Khachikyan

Mathematics, Physics, and Computer Science Faculty Articles and Research

In solar–terrestrial physics, there is an open question: does a geomagnetic storm affect earthquakes? We expand research in this direction, analyzing the seismic situation after geomagnetic storms (GMs) accompanied by the precipitation of relativistic electrons from the outer radiation belt to form an additional radiation belt (RB) around lower geomagnetic lines. We consider four widely discussed cases in the literature for long-lived (weeks, months) RBs due to GMs and revealed that the 1/GMs 24 March 1991 with a new RB at L~2.6 was followed by an M7.0 earthquake in Alaska, 30 May 1991, near footprint L = 2.69; the 2/GMs …

Dyonic Taub-Nut-Ads Space Phase Structure, Mohamed Tharwat

Theses and Dissertations

The Taub-NUT spacetime remains to hold many mysteries more than half a century after its discovery. The metric's controversy owes largely to the nut charge and the existence of Misner strings. Traditionally the metric is treated in the euclidean signature, this treatment hides the Misner strings. We treat the Taub-NUT spacetime with the Misner strings visible, not enforcing the time periodicity condition. We examine the phase structure belonging to three different horizon geometries. We deal with the hyperbolic, flat and spherical cases. We consider the stable phases, the phase transitions that exist between them, and find the preferable phases in …

Using Deep Neural Networks To Classify Astronomical Images, Andrew D. Macpherson

Honors Projects

As the quantity of astronomical data available continues to exceed the resources available for analysis, recent advances in artificial intelligence encourage the development of automated classification tools. This paper lays out a framework for constructing a deep neural network capable of classifying individual astronomical images by describing techniques to extract and label these objects from large images.

The Meaning Of Dark, Light And Shadows: Inferences In Art, Materiality And Cultural Practices, Frank Prendergast

Book/Book Chapter

Our visual awareness relies on light acting on the eye to perceive materiality and colour. Medieval thought wrestled to articulate and comprehend its nature. The notebooks of Leonardo Da Vinci, for example, included his descriptions to define light and make comparisons so as to differentiate between light and shadow. His focus was on the illumination of surfaces from the perspective of a painter, seeing shadows as ‘the diminution of light by the intervention of an opaque body’ and ‘the counterpart of luminous rays’. In his mind, a shadow ‘stood between light and darkness’, with darkness being ‘the absence of light’. …

Searching For Anomalous Extensive Air Showers Using The Pierre Auger Observatory Fluorescence Detector, Andrew Puyleart

Dissertations, Master's Theses and Master's Reports

Anomalous extensive air showers have yet to be detected by cosmic ray observatories. Fluorescence detectors provide a way to view the air showers created by cosmic rays with primary energies reaching up to hundreds of EeV . The resulting air showers produced by these highly energetic collisions can contain features that deviate from average air showers. Detection of these anomalous events may provide information into unknown regions of particle physics, and place constraints on cross-sectional interaction lengths of protons. In this dissertation, I propose measurements of extensive air shower profiles that are used in a machine learning pipeline to distinguish …

The Kepler Problem On Complex And Pseudo-Riemannian Manifolds, Michael R. Astwood

Theses and Dissertations (Comprehensive)

The motion of objects in the sky has captured the attention of scientists and mathematicians since classical times. The problem of determining their motion has been dubbed the Kepler problem, and has since been generalized into an abstract problem of dynamical systems. In particular, the question of whether a classical system produces closed and bounded orbits is of importance even to modern mathematical physics, since these systems can often be analysed by hand. The aforementioned question was originally studied by Bertrand in the context of celestial mechanics, and is therefore referred to as the Bertrand problem. We investigate the qualitative …

Using Methanol Masers To Probe High Mass Star Forming Regions, Naomi S. Shechter, Anuj P. Sarma

DePaul Discoveries

Compared to low mass stars, the formation of high mass stars is not well understood. To understand better how high mass stars form, we can utilize masers, naturally amplified point sources of microwave radiation. One example is the methanol maser, which falls into two categories. Class I methanol masers form in the bipolar outflows from the protostar, and Class II masers form in the accretion disk. Their compact size and intensity make them an excellent source of information about the process of high mass star formation. We compiled a modest database of Class I and II methanol masers through a …

Active Magnetic Radiation Shielding For Long-Duration Human Spaceflight, Kristine Ferrone

Dissertations and Theses (Open Access)

Exploration of interplanetary space presents dramatic hazards to human survival.

Space radiation hazards outside the protection of the Earth’s magnetosphere can

produce both acute and chronic health risks and thus become limiting factors for

NASA’s planned mission to Mars by the 2030s. Radiation exposure on a Mars mission

is delivered primarily by high energy ions from galactic cosmic rays and moderate

energy protons from solar particle events. The chronic radiation dose due to galactic

cosmic rays on a typical Mars mission is on the order of 1 Sv, and additional acute

radiation dose from solar flares can reach over 4 …

A Review On Superluminal Physics And Superluminal Communication In Light Of The Neutrosophic Logic Perspective, Victor Christianto, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In a recent paper, we describe a model of quantum communication based on combining consciousness experiment and entanglement, which can serve as impetus to stop 5G-network-caused diseases. Therefore, in this paper we consider superluminal physics and superluminal communication as a bridge or intermediate way between subluminal physics and action-at-a-distance (AAAD) physics, especially from neutrosophic logic perspective. Although several ways have been proposed to bring such a superluminal communication into reality, such as Telluric wave or Telepathy analog of Horejev and Baburin, here we also review two possibilities: quaternion communication and also quantum communication based on quantum noise. Further research is …

Fluctuating Hydrodynamics Of Reactive Liquid Mixtures, Changho Kim, Andy. Nonaka, John Bell, Alejandro Garcia, Aleksandar Donev

Faculty Publications

Fluctuating hydrodynamics (FHD) provides a framework for modeling microscopic fluctuations in a manner consistent with statistical mechanics and nonequilibrium thermodynamics. This paper presents an FHD formulation for isothermal reactive incompressible liquid mixtures with stochastic chemistry. Fluctuating multispecies mass diffusion is formulated using a Maxwell–Stefan description without assuming a dilute solution, and momentum dynamics is described by a stochastic Navier–Stokes equation for the fluid velocity. We consider a thermodynamically consistent generalization for the law of mass action for non-dilute mixtures and use it in the chemical master equation (CME) to model reactions as a Poisson process. The FHD approach provides remarkable …

An Analysis Of Frenkel Defects And Backgrounds Modeling For Supercdms Dark Matter Searches, Matthew Stein

Physics Theses and Dissertations

Years of astrophysical observations suggest that dark matter comprises more than ~80 % of all matter in the universe. Particle physics theories favor a weakly-interacting particle that could be directly detected in terrestrial experiments. The Super Cryogenic Dark Matter Search (SuperCDMS) Collaboration operates world-leading experiments to directly detect dark matter interacting with ordinary matter. The SuperCDMS Soudan experiment searched for weakly interacting massive particles (WIMPs) via their elastic-scattering interactions with nuclei in low-temperature germanium detectors.

During the operation of the SuperCDMS Soudan experiment, ²¹⁰Pb sources were installed to study background rejection of the Ge detectors. Data from these sources …

Thinking Out Loud On Early Creation Through The Lens Of Hermeneutics Of Sherlock Holmes (Towards A Model Of Universe Based On Turbulence-Generated Sound Theory), Victor Christianto, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In recent years, apparently the Big Bang as described by the Lambda CDM-Standard Model Cosmology has become widely accepted by majority of physics and cosmology communities. Even some people have concluded that it has no serious alternative in horizon. Is that true? First, as we argued elsewhere, Big Bang story relies on singularity. In other words, when we are able to describe the observed data without invoking singularity, then Big Bang model is no longer required. Therefore, here we explore a few alternative stories other than Big Bang story, which most cosmologists believe it is the nearest to Biblical account …

Evaluating The Effectiveness Of Current Atmospheric Refraction Models In Predicting Sunrise And Sunset Times, Teresa Wilson

Dissertations, Master's Theses and Master's Reports

The standard value for atmospheric refraction on the horizon of 34', used in all publicly available sunrise and sunset calculators, is found to be inadequate. The assumptions behind atmospheric models that predict this value fail to account for real meteorological conditions. The result is an uncertainty of one to five minutes in sunrise and sunset predictions at mid-latitudes (0° - 55° N/S). A sunrise/set calculator that interchanges the refraction component by varying the refraction model was developed. Two atmospheric refraction models of increasing complexity were tested along with the standard value. The predictions were compared with data sets of observed …

Energy From Active Galactic Nuclei And The Effects On Host Spiral Galaxies, Amanda Schilling

Graduate Theses and Dissertations

I have investigated the energy output of active galactic nuclei (AGN) in order to understand how these objects evolve and the impact they may have on host galaxies. First, I looked at a sample of 96 AGN at redshifts $z \sim 2, 3,$ and $4$ which have imaging and thus luminosity measurements in the $griz$ and $JHK$ observed wavebands. For these galaxies, I have co-epochal data across those bands which accounted for variability in AGN luminosity. I used the luminosity measurements in the five bands to construct spectral energy distributions (SED) in the emitted optical-UV bands for each AGN. I …

Enhancing The Science Return Of Lunar Surface Studies: Analysis Of Rediscovered Data From Apollo 17'S Lunar Seismic Profiling Experiment, Deanna Phillips, Richard Miller

Von Braun Symposium Student Posters

No abstract provided.

Characterizing Crop Photomultiplier Tube Behavior At 1000 Volts, Zachary T. Smith

UCARE: Research Products

In an effort to prolong the lifetime of their Photomultiplier tubes (PMTs), the Cosmic Ray Observatory Project (CROP) made the decision to begin operating the PMTs at an operating voltage of 1000 Volts. The aim of this project was to characterize the fundamental behavior of the PMTs at this operating voltage using several tests. These tests include determining the optimal threshold level of the PMTs, the PMT efficiency, and the time stability of the PMT's output.

Dark Matter Halo Concentration And The Evolution Of Spiral Structure In N-Body, Barred Spiral Galaxies, Jazmin Esmeralda Berlanga Medina

Graduate Theses and Dissertations

Motivated by the evidence of relationships between pitch angle (the tightness of spiral arm structure in the disk), P, and various indicators of central mass concentration, as well as the theoretical relationship between halo mass concentration and the density of visible matter in the central part of the galaxy, we look at a possible relationship between P and cvir (the virial concentration of the dark matter halo) in N-body simulations of barred, spiral galaxies. We also look at the evolution of pitch angle over time in higher temporal resolution than any data currently available in the literature. We find that …

Question 1: Star Speeds; Question 2: Slurping Gasoline, Larry Weinstein

Physics Faculty Publications

One piece of evidence that the center of our galaxy contains a super-massive black hole came from measuring the speed of a star orbiting that black hole. What is the maximum speed of that star?

If instead of carrying their gas in fuel tanks, cars “slurped up” a stream of gas as they drove, how thick a stream of gas would each car need?

Diffusive Transport Enhanced By Thermal Velocity Fluctuations, Alejandro Garcia, A. Donev, A. De La Fuente, J. B. Bell

Faculty Publications

We study the contribution of advection by thermal velocity fluctuations to the effective diffusion coefficient in a mixture of two identical fluids. We find good agreement between a simple fluctuating hydrodynamics theory and particle and finite-volume simulations. The enhancement of the diffusive transport depends on the system size L and grows as ln⁡(L/L0) in quasi-two-dimensional systems, while in three dimensions it scales as L0-1-L-1, where L0 is a reference length. Our results demonstrate that fluctuations play an important role in the hydrodynamics of small-scale systems.

A Hybrid Particle-Continuum Method For Hydrodynamics Of Complex Fluids, Alejandro Garcia, A. Donev, J. B. Bell, B. Alder

Faculty Publications

A previously developed hybrid particle-continuum method [J. B. Bell, A. Garcia, and S. A. Williams, Multiscale Model. Simul., 6 (2008), pp. 1256–1280] is generalized to dense fluids and two- and three-dimensional flows. The scheme couples an explicit fluctuating compressible Navier–Stokes solver with the isotropic direct simulation Monte Carlo (DSMC) particle method [A. Donev, A. L. Garcia, and B. J. Alder, J. Stat. Mech. Theory Exp., 2009 (2009), article P11008]. To achieve bidirectional dynamic coupling between the particle (microscale) and continuum (macroscale) regions, the continuum solver provides state-based boundary conditions to the particle subdomain, while the particle solver provides flux-based boundary …

Computational Fluctuating Fluid Dynamics, Alejandro Garcia, J. B. Bell, S. Williams

Faculty Publications

This paper describes the extension of a recently developed numerical solver for the Landau-Lifshitz Navier-Stokes (LLNS) equations to binary mixtures in three dimensions. The LLNS equations incorporate thermal fluctuations into macroscopic hydrodynamics by using white-noise fluxes. These stochastic PDEs are more complicated in three dimensions due to the tensorial form of the correlations for the stochastic fluxes and in mixtures due to couplings of energy and concentration fluxes (e.g., Soret effect). We present various numerical tests of systems in and out of equilibrium, including time-dependent systems, and demonstrate good agreement with theoretical results and molecular simulation

Stochastic Hard-Sphere Dynamics For Hydrodynamics Of Non-Ideal Fluids, Alejandro Garcia, A. Donev, B. J. Alder

Faculty Publications

A novel stochastic fluid model is proposed with a nonideal structure factor consistent with compressibility, and adjustable transport coefficients. This stochastic hard sphere dynamics (SHSD) algorithm is a modification of the direct simulation Monte Carlo algorithm and has several computational advantages over event-driven hard-sphere molecular dynamics. Surprisingly, SHSD results in an equation of state and a pair correlation function identical to that of a deterministic Hamiltonian system of penetrable spheres interacting with linear core pair potentials. The fluctuating hydrodynamic behavior of the SHSD fluid is verified for the Brownian motion of a nanoparticle suspended in a compressible solvent.

Algorithm Refinement For Fluctuating Hydrodynamics, Alejandro Garcia, S. Williams, J. B. Bell

Faculty Publications

This paper introduces an adaptive mesh and algorithm refinement method for fluctuating hydrodynamics. This particle-continuum hybrid simulates the dynamics of a compressible fluid with thermal fluctuations. The particle algorithm is direct simulation Monte Carlo (DSMC), a molecular-level scheme based on the Boltzmann equation. The continuum algorithm is based on the Landau–Lifshitz Navier–Stokes (LLNS) equations, which incorporate thermal fluctuations into macroscopic hydrodynamics by using stochastic fluxes. It uses a recently developed solver for the LLNS equations based on third-order Runge–Kutta. We present numerical tests of systems in and out of equilibrium, including time-dependent systems, and demonstrate dynamic adaptive refinement by the …