Physics Commons^™

Streamer Discharge Modeling For Plasma-Assisted Combustion, Stuart Reyes, Shirshak Kumar Dhali

Electrical & Computer Engineering Faculty Publications

Some of the popular and successful atmospheric pressure fuel/air plasma-assisted combustion methods use repetitive ns pulsed discharges and dielectric-barrier discharges. The transient phase in such discharges is dominated by transport under strong space charge from ionization fronts, which is best characterized by the streamer model. The role of the nonthermal plasma in such discharges is to produce radicals, which accelerates the chemical conversion reaction leading to temperature rise and ignition. Therefore, the characterization of the streamer and its energy partitioning is essential to develop a predictive model. We examine the important characteristics of streamers that influence combustion and develop some …

Detecting Anomalous Srf Cavity Behavior With Unsupervised Learning, Hal Ferguson, Jiang Li, Adam Carpenter, Chris Tennant, Dillon Thomas, Dennis Turner

Electrical & Computer Engineering Faculty Publications

We present an unsupervised learning framework for detecting anomalous superconducting radio-frequency (SRF) cavity behavior at the Continuous Electron Beam Accelerator Facility (CEBAF), emphasizing its initial performance and effectiveness. Key to the system’s success was the development of data acquisition systems (DAQs) that capture fast-sampled, information-rich signals, essential for detecting transient effects. The approach involves creating daily cavity-specific models using principal component analysis to handle variations in rf signal behavior and mitigate performance degradation from data drift. This unsupervised method eliminates the need for expensive labeling by continuously updating models with recent data. Deployed and operational for 3 months before a …

Cfd Analysis Of Hydrodynamic Cavitation Through An Orifice: Influence Of Different Inlet Pressures And Number Of Orifice Holes, Lemthong Chanphavong, Vongsavanh Chanthaboune, Keophousone Phonhalath

ASEAN Journal on Science and Technology for Development

Hydrodynamic cavitation (HC) is considered an energy-efficient process with high potential for utilization in many chemical processes. This study presents a computational fluid dynamics (CFD) analysis of cavitating flow through an orifice with a constant flow area. The Reynolds-Averaged Navier-Stokes (RANS) equations, coupled with turbulence and cavitation models, are employed to capture the complex flow behaviors. The effects of inlet pressures and number of orifice-holes on cavitation behavior are investigated. Result of the numerical simulation is validated with the existing experimental data from the literature. The CFD study revealed that cavitation initiates just behind the inlet edge of the orifice …

Structural Analysis And Design Methodologies Of Roller Coasters, Benjamin Komar

Williams Honors College, Honors Research Projects

This project explores the structural analysis behind the design of roller coaster tracks and supports as practiced by modern engineers. It also examines various roller coaster design methods currently in use. This research will be used to craft a detailed explanation of the roller coaster design process. Additionally, a 3D model of a roller coaster was developed based on the researched design procedures, featuring three track sections with different loading conditions to create a supporting structure for 2D truss analysis. The results of the truss analysis were then compared to those obtained using RISA-3D, a finite element structural design software.

0th Order Solutions Of The Wavefunctions For The Quantum Elliptical Box And Microstrip Antenna, Nishtha Tikalal

Honors Undergraduate Theses

For a quantum particle confined to a two-dimensional elliptical box or electromagnetic wave in a microstrip antenna, geometrical and boundary condition interplay result in a spectrum of spatial patterns. Due to the asymmetrical nature of the ellipse, we are faced with continuous symmetry reductions, leaving both degenerate and nondegenerate solutions. Here, we present a complete derivation of an analytical solution and visualizations of the fundamental wavefunctions for both Dirichlet and Neumann boundary conditions respectively corresponding to the quantum elliptical box and the elliptical microstrip antenna.

We demonstrate that the eigenmodes, governed by eccentricity, directly correspond to the modal field distributions …

Bounded Compactness From G(E)Up, Jonas Mureika, Roberto Casadio, Ilim Irfan Çimdiker, Octavian Micu

Physics Faculty Works

We analyse how different Generalised Uncertainty Principles could place bounds on the compactness of self-gravitating systems. By considering existing experimental bounds on the relevant parameters, we conclude that the compactness of large astrophysical objects is bounded above by the inverse of the GUP parameter, which would naturally be of order one. Conversely, the existence of black holes imposes stronger bounds on those parameters.

Personalized Physics Learning Through Ai: Insights From Problem Generation, Chatbot Dialogues, And Intelligent Tutoring Systems, Atharva Dange

Physics Dissertations - Archive

Artificial intelligence (AI) is poised to transform science education, yet questions remain on how best to integrate these technologies into teaching and learning. This dissertation investigates the use of AI-driven tools in university physics courses through three complementary studies. In the first study, a generative language model (ChatGPT) was used to create novel physics homework problems aligned with course objectives. Analysis showed that, after expert vetting, AI-generated questions can foster higher-order problem-solving and reduce student reliance on solution memorization, though careful instructor oversight is required to ensure accuracy. The second study embedded an AI chatbot as a learning aid in …

Development And Application Of Gpu Based Monte Carlo Simulation Techniques In Radiation Medicine, Satzhan Sitmukhambetov

Physics Dissertations - Archive

Cancer remains a significant public health challenge, with treatments like radiation therapy forming a cornerstone of modern care. To address this challenge, advanced computer simulations can improve radiotherapy in two primary ways. From one hand, mechanistic simulations help elucidate the fundamental radiobiological working principles, which could contribute to the clinical advancements from a bottom-up framework. On the other hand, modality simulations could help design better clinical systems with better detection and therapeutic capabilities. This research enhances these critical simulation tools by introducing two significant developments.

First, this work introduces a metaphase DNA model into a microscopic Monte Carlo simulation framework …

Uncertainty In Solar Wind Propagation: An Analysis Of L1 To Earth Variability And The Implications For Geospace Modeling In Space Weather Operations, Espen T. Fredrick

Physics Dissertations - Archive

As humanity's technological dependence grows, so does its vulnerability to space weather. Space weather describes solar-driven phenomena in the near-Earth space environment and their terrestrial effects. Many of these effects occur due to the interaction of the solar wind and Earth's magnetosphere. The solar wind originates at the solar corona and carries solar plasma and magnetic field outward through the solar system. This magnetic field, known as the interplanetary magnetic field (IMF) during transit, can undergo magnetic reconnection with Earth's geomagnetic field when oppositely aligned field lines converge. This process transfers energy into Earth's magnetosphere, driving space weather phenomena.

Space …

Characterizing The Earth's Magnetosheath With In Situ Measurements, Hector A. Salinas

Physics Dissertations - Archive

Earth’s magnetosheath is a region of shocked plasma that mediates energy and momentum transfer from the solar wind to the magnetosphere. The dynamics and thus the plasma structures of this region are highly dependent on upstream solar wind conditions. As such, the region is often characterized as a turbulent environment, with the most intense periods of turbulence occurring often under quasi-parallel bow shock conditions. This magnetosheath turbulence displays as variable and large-scale fluctuations with in-situ measurements. Given that turbulence is a characteristic feature of the magnetosheath, this dissertation asks two questions: (1) How are plasma structures inside the sheath affected …

Study Of Structural Changes In Bone From Osteogenesis Imperfecta Using Positron Annihilation Lifetime Spectroscopy, Pablo Kohlmann Garcia, Richard Vallery

Student Summer Scholars Manuscripts

Osteogenesis Imperfecta (OI), commonly referred to as Brittle Bone Disease, is a genetic disorder that results in increased bone fragility. There are many known variations, with four of them being the most common and each with a different level of severity. However, the exact causes of OI and their molecular and structural effects on bones are largely unknown. To investigate the relationship between nanoscale bone structure and disease severity, this research investigates OI by using positron annihilation lifetime spectroscopy (PALS) to understand whether normal bone structure differs from OI-infected bones. Using this method, positrons are directed towards mice’s bones, forming …

Periodic Trends In The Electronic And Magnetic Structure Of Superatomic 3d Transition Metal Chalcogenide Clusters, Gabriel Bohannon

Theses and Dissertations

We have systematically investigated the electronic structure of octahedral transition metal chalcogenide clusters, TM₆S₈(CO)₆, in which the transition metal atoms are from the 3d series in order to identify if periodic properties emerge. We were motivated by the identification of closed electronic shells with electron counts of 96, 100 and 114 in similar clusters from the 4d and 5d transition metal series. Further motivation was the finding of a dual-shell closing in the Fe₆S₈(CN)₆^5- cluster. This cluster is stabilized with a large spin magnetic moment due to the …

Multiphysics Modeling Of Material Response To High-Intensity X-Ray And Laser Pulses: Heating, Ablation, And Plasma Expansion, Youssef Abouhussien

Theses and Dissertations

This dissertation presents a computational framework to investigate material response under high-intensity X-ray fluxes produced by an exo-atmospheric nuclear detonation and laser-material irradiations, with a focus on heating, ablation, and plasma expansion phenomena relevant to satellite vulnerability and high-energy-density environments. A hybrid Monte Carlo and Two-Temperature Model (MC-TTM) was developed to simulate X-ray and laser energy deposition and thermal relaxation in metals and semiconductors across a range of X-ray and laser pulse durations from femtoseconds to nanoseconds. Results demonstrate distinct thermal behavior between materials, with ablation thresholds and phase transitions captured in good agreement with experimental data.

In parallel, a …

Beyond The Phonon Gas Model (Pgm): Unraveling The Unique Mechanistic Processes Dictating Thermal Transport In Highly Anharmonic And Disordered Materials, Sandip Thakur

Open Access Dissertations

Thermal transport in nonmetallic solids has traditionally been described by the phonon gas model (PGM), in which heat is carried by weakly interacting phonon quasiparticles in an ordered crystalline lattice. However, this model breaks down in materials characterized by strong anharmonicity, dynamic disorder, or structural complexity, features prevalent in many next-generation materials used in energy conversion, optoelectronics, and thermal management. This dissertation investigates thermal transport in such complex materials, including metal halide perovskites (MHPs), covalent organic frameworks (COFs), metal organic frameworks (MOFs), and 2D-3D heterostructures, through large-scale molecular dynamics (MD) simulations and frequency-resolved spectral analyses.

In MHPs, the work reveals …

Further Results On Learning Quantum Measurement Classes: Quantum Pac Model For Povm Hypothesis Classes, Arka Prabha Das

Electronic Theses & Dissertations (2024 - present)

This thesis investigates the problem of learning from quantum systems, where each example consists of a quantum state paired with a classical outcome. The task centers on choosing an effective measurement rule from a fixed set to enable accurate prediction of the classical outcome from the quantum state. A central focus lies in understanding whether joint measurement strategies that cannot be separated into local operations offer a real benefit in terms of the number of examples needed for successful learning. We examine conditions under which a non-separable measurement within a given hypothesis class achieves strictly better sample complexity bounds compared …

Backgrounds And Efficiencies For Low-Energy Searches, And Improved Calibration Techniques In The Lux-Zeplin Dark Matter Experiment, Gregory M. Blockinger

Electronic Theses & Dissertations (2024 - present)

The full understanding of dark matter has eluded physicists for many years. While there is abundant astrophysical evidence across many scales, the exact nature of this matter, which comprises about 25% of the Universe’s energy density, remains unknown. Weakly Interacting Massive Particles (WIMPs) are one of the leading theoretical candidates, and numerous ex- periments have searched for their interactions. In recent decades, dual-phase Time Projection Chambers (TPCs) have become the leading technology in this search. The LUX-ZEPLIN (LZ) detector is one such xenon-based experiment, operating nearly a mile underground in the Black Hills of South Dakota at the Sanford Underground …

Applying The Lagrangian Variational Method To Atom Interferometry, Jeffrey W. Heward

College of Graduate Studies: Theses & Dissertations

Atom interferometry in Bose-Einstein condensate systems has emerged as a promising technique for precision metrology. The dynamics of these systems are well-described by the Gross-Pitaevskii equation (GPE), but direct numerical solution of this equation is infeasible for realistic systems. We use the Lagrangian Variational Method (LVM) to approximate solutions of the GPE in 1D and 3D, and we compare the LVM results to the exact solutions. We also present 3D LVM results for a case where numerical solution of the GPE is infeasible.

Investigation Of A Busemann Intake At Negative Angle Of Attack, Mark E. Noftz, Andrew N. Bustard, Nicholas J. Bisek, Thomas J. Juliano, Joseph S. Jewell

Publications

A high-speed, shape-transitioned, inward-turning intake was tested in Purdue’s Boeing/AFOSR Mach 6 Quiet Tunnel. The inlet model, called the Indiana Inlet (INlet), had a total contraction ratio of 4.68:1 and a design point of Mach 6 at 0° angle of attack. The model was outfitted with a suite of high-frequency pressure transducers, and the external flowfield was imaged with high-speed schlieren photography. The INlet was tested under low freestream disturbance levels for a variety of freestream unit Reynolds numbers and at-4° angle of attack. An unsteady shockwave near the leading edge of the inlet forebody, indicative of boundary layer separation, …

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 …

Effect Of Activation Temperature On Quantum Efficiency And Lifetime Of Nea Truncated Nanocone Array Gaas Photocathode, Md. Aziz Arroyo Rahman, Md Abdullah Mamun, Shukui Zhang, Hani E. Elsayed-Ali

Physics Faculty Publications

This study investigates the quantum efficiency (QE) and operational lifetime of a negative electron affinity GaAs truncated nanocone array (TNCA) photocathode benchmarked against a conventional flat GaAs photocathode under varying activation temperatures. The TNCA structure demonstrated a QE of up to 13.6% at 590 nm with room temperature (RT) activation—approximately 1.5 times higher than its flat counterpart. This enhancement is due to Mie resonance effects within the nanostructure, as confirmed by finite-difference time-domain simulations. Moreover, the TNCA photocathode exhibits significantly extended charge lifetime, with enhancement factors of ∼6.1 and ∼19.8 under RT and 50 °C activations, respectively. These gains are …

Deep Underground Neutrino Experiment Data Caching With Frontier, Alexander Rahe

Graduate Research Theses & Dissertations

The Deep Underground Neutrino Experiment (DUNE) is an unprecedented long baseline neutrino experiment that aims to measure various neutrino mixing parameters. With state-of-the-art technology, DUNE will measure neutrino mixing angles (θ13, θ12, θ23) and a Charge-Parity (CP) violating phase (δcp) with precision and will determine the elusive mass ordering. In order to accomplish these goals, scientists all over the world must have quick and reliable access to the data provided by the DUNE detectors. The data caching system known as Frontier is a distributed database caching system that was previously used in other large particle physics experiments for this purpose. …

Highly Sensitive Diffractive Optical Structures For Detection Of Volatile Organic Compounds, Faolan Radford Mcgovern

Doctoral

From aerospace to agriculture, sensors play a fundamental role in many aspects of modern life. Sensors form an integral part of the complex systems and devices required for the continued functioning and development of services and industries across society. The use of sensors is paramount in areas affecting human health, one such area being the monitoring of indoor air quality, in particular the detection of volatile organic compounds (VOCs). Human contact with VOCs has been associated with many health complications, including skin and eye irritation, cardiovascular damage, and cancers. Optical, electrical, gravimetric, and chemical sensors have been developed for VOC …

Structural Optimization And Stability Enhancement Of Uba(2) And Ntl9 Using The Computational Tool: Emcast, Bahar Ghazi Esfahani

Graduate Student Theses, Dissertations, & Professional Papers

This study enhances protein stability prediction by refining EmCAST (Empirical C-Alpha Stability Tool), a computational tool used to identify stabilizing mutations in protein domains. We applied EmCAST to two model proteins: the α-helical ubiquitin-associated domain 2 (UBA(2)) and the α/β N-terminal domain of ribosomal protein L9 (NTL9). Protein stability is critical for proper function, and mutations can lead to misfolding and disease. To validate EmCAST’s predictions, guanidine hydrochloride-induced denaturation was monitored using circular dichroism (CD) spectroscopy for both wild-type and mutant variants. Results guided refinements to EmCAST’s algorithm, incorporating new experimental datasets to improve accuracy. Additionally, we examined the assumption …

Modeling Energetic Electron Precipitation: Radiation Belt Loss, Its Drivers, And Atmospheric Impacts, Zhi Gu Li

Graduate Theses, Dissertations, and Problem Reports (ETD)

Energetic electrons in the terrestrial outer radiation belt present significant hazards to spacecraft systems and human operations in space. The intensity of these electrons can vary rapidly and dramatically during geomagnetic storms, governed by a complex competition between acceleration and loss processes. Among these, precipitation into the atmosphere via resonant wave-particle interaction acts as a key loss mechanism. This dissertation focuses on improving the quantification of energetic electron precipitation using physics-based modeling constrained by low-altitude satellite observations.

We begin by developing and validating the Drift-Diffusion model, which simulates low-altitude electron dynamics while accounting for azimuthal drift, pitch-angle diffusion, and atmospheric …

Optical Measurements Of Magnetic Fields In Low-Temperature Plasmas Via Quantum Spectroscopy, Tyler James Gilbert

Graduate Theses, Dissertations, and Problem Reports (ETD)

Accurate characterization of the magnetic field strength and direction within a plasma is increasingly important as experiments attempt to probe the physics of plasmas at kinetic scales. Non-perturbative laser-based diagnostics which are spatially and temporally localized—such as laser-induced fluorescence (LIF) and Thomson scattering for the measurement of ion and electron distribution functions, respectively—are increasingly relied on for measurements in laboratory plasmas. This work seeks to develop a spatially and temporally localized non-perturbative laser-based diagnostic for the measurement of magnetic fields in laboratory-relevant plasmas. Two such techniques are investigated here: Zeeman-split LIF and quantum beat spectroscopy (QBS).

Zeeman-split LIF measures the …

Novel Phenomena In Chiral And Disordered Crystals, Zachary Louis Romestan

Graduate Theses, Dissertations, and Problem Reports (ETD)

The concept of symmetry is central to our understanding of the physical world. Core symmetries—comprising time reversal, charge conjugation, spatial inversion, and rotation—are integral in maintaining essential conservation laws. They also play a critical role in the manifestation of new quantum phases that arise when these symmetries are disrupted. At the heart of contemporary research in condensed matter physics is the exploration of how basic symmetries interact with material imperfections. This examination delves deeply into the ways that inherent symmetrical properties and structural anomalies within materials influence each other, providing crucial insights into the field. This dissertation presents an investigation …

Optical Properties Of Rare Earth Doped Molybdenum Trioxide Thin Films, Jessica Fink

Graduate Theses/Dissertations

This study aims to investigate the optical properties of Dy-doped MoO₃ thin films. MoO₃ is a transition metal oxide that is wide band gap semiconductor. As a transition-metal oxide, it has been widely studied for its tunable properties. However, there is little literature on the subject of Dysprosium doped MoO₃, and none found as of now on thin film Dy-MoO₃ . This indicates that this topic is at best under reported, and thin film Dy-MoO₃ possesses a certain novelty. Unlike most transition metal oxides, undoped MoO₃ has a negligible crystal field splitting. This is due to the electron vacancy of …

Synthesis And Characterization Of Doped Rare-Earth Zinc Alloys, Partha Das

Graduate Theses/Dissertations

Rare-Earth-Zinc (RE-Zn) alloys doped with manganese represent a promising class of materials with diverse applications in magnetic, electronic, and thermoelectric devices. These alloys hold significant potential owing to the unique combination of rare-earth elements' properties with the versatility of zinc, augmented by manganese doping. In this study, I present the successful synthesis of ErMn_0.2Zn_11.8 alloys, achieved through self-flux method. The synthesized crystals were characterized using electron dispersive spectroscopy (EDS) and single crystal X-ray diffraction (XRD). Additionally, magnetic measurements were performed to investigate the magnetic properties. Future plans include DFT calculations and comparison study between Rare-Earth-Zinc alloys with …

Evaluation Of The Stability Of Argan Oil Nanoemulsions Formulated And Optimized Through Experimental Design For Dermatological Applications, Yousra Mdarhri, Ikram Bouziane, Narjisse Mokhtari, Lama Rissouli, Ahmed Touhami, Fakhita Touhami, Mohamed Chabbi

Physics & Astronomy Faculty Publications

Argan oil is a highly sought-after natural product renowned for its therapeutic and rejuvenating properties. This study focused on harnessing its dermatological bioactivity by developing stable nanoemulsions through a simple low-energy method using a single non-ionic surfactant. The composition and properties of Argan oil were analyzed using High-Performance Liquid Chromatography (HPLC), Gas Chromatography (GC), and quality indexes, adhering to international standards. The effect of system composition on stability was evaluated using a pseudo-ternary phase diagram and Phase Inversion Composition (PIC) emulsification technique. Optimal process parameters for producing stable nanoemulsion were determined through Response Surface Methodology (RSM) analysis. The resulting nanoemulsions …

Size Dependent Thermodynamic Properties Of Dppc, Zhenghao Pan

Graduate Research Theses & Dissertations

This study explores the viability of measuring the melting transition behavior in a simple unilamellar vesicle (LUV/SUV) liposome (DPPC surfactant) system using size data from Dy- namic Light Scattering (DLS). The melting transition of phospholipid membranes has been a focal point of studies in biological systems. Conventionally, the transition temperature of a membrane system is measured using either spectroscopy or Differential Scanning Calorimetry (DSC). By assuming that the bilayer volume is conserved, it is shown that DLS provides a transition signal comparable to that of DSC and aligns with known data. The data are fit- ted using Van’t Hoff’s equation. …