Digital Commons Network^™

Rotating Scatter Mask System Optimization Study For Determining Optimal Image Recreation, Seth L. Grover

Theses and Dissertations

The Rotating Scatter Mask (RSM) system is a radiation imaging technology currently limited by the mask design and governing identification algorithm parameters. To optimize the RSM design, Dakota—an optimization software—was integrated with a ray tracing code that simulates particle interactions with the RSM detector, and with the Locally Competitive Algorithm (LCA), which reconstructs the source image based on the ray tracing code’s Detector Response Matrix (DRM). Since the original ray tracing code was developed in MATLAB, it was translated into Python to improve compatibility with both Dakota and LCA. The Python version of the ray tracing code was then integrated …

Fused-Silica Microelectromechanical Systems For Relative Gravimetry, Ethan Doerstling

Theses and Dissertations

Gravimeters are devices that measure gravitational acceleration which can be used by the United States Air Force (USAF) in the areas of navigation and remote sensing. Fused-silica microelectromechanical systems (MEMS) devices offer capabilities to make inexpensive relative gravimeters with higher thermal stability than common silicon devices while maintaining good gravitational sensitivity. The fused-silica devices in this research were designed, simulated, fabricated, and tested to observe their performance as gravimeters. The devices exhibit properties of highly sensitive accelerometers but the current designs do not qualify as gravimeters. This study provides information to improve the sensitivity and stability of these fused-silica MEMS …

Constraining Nuclear Data Uncertainty Requirements For The 19F(A, N)22Na Reaction For Non-Proliferation Applications, Tyler R. M. Smith

Theses and Dissertations

This thesis explores the requirements on nuclear data uncertainties needed for the use of the ¹⁹F(α, n)²²Na reaction for nuclear non-proliferation applications. An overview of how neutrons are produced from alpha decays in a UF₆ medium is discussed. Calculation demonstrate the role nuclear data uncertainties effect the neutron yield and energy spectra as a function of enrichment.

Excitons And Polaritons In Two-Dimensional Materials Heterostructures - Applications As Qubits, Time Crystals, And Superfluids, Gabriel Pimenta Martins

Dissertations, Theses, and Capstone Projects

This dissertation is concerned with exploring the properties and applications of excitons and polaritons in two-dimensional (2D) materials and heterostructures. It focuses on their potential to form qubits, time crystals, and superfluids. The work is motivated by the unique electronic and optical properties of 2D materials—specifically, their ability to host strongly bound excitons and hybrid light-matter quasiparticles known as polaritons. By exploiting a combination of theoretical modeling and numerical simulations, this work examines the behavior of these quasiparticles under various physical conditions, including strain-induced pseudomagnetic fields, optical microcavities, and periodic external potentials.

The first part of this dissertation is devoted …

Nonlinear Physics Of Parity-Broken Fluids, Sudheesh Srivastava

Dissertations, Theses, and Capstone Projects

This thesis explores parity-breaking mechanisms, nonlinear wave phenomena, and localization transitions across different physical contexts. First, we examine modulation instability in parity-breaking systems, deriving modified nonlinear Schr¨odinger equations that reveal direction dependent instabilities. Next, we investigate wave turbulence, demonstrating numerically that parity-breaking dispersion significantly alters turbulent cascades and modifies their statistical properties. Lastly, we analyze localization in quasiperiodic tight- binding model based on polariton condensate lattice. Collectively, these studies illustrate the universal role of symmetries and nonlinear interactions in shaping macroscopic behaviors, facilitating interdisciplinary insights.

Search For Gravitational Waves Emitted From Sn 2023ixf, A. G. Abac, R. Abbott, Teviet Creighton, Mario C. Diaz, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present the results of a search for gravitational-wave transients associated with core-collapse supernova SN 2023ixf, which was observed in the galaxy Messier 101 via optical emission on 2023 May 19, during the LIGO–Virgo–KAGRA 15th Engineering Run. We define a five-day on-source window during which an accompanying gravitational-wave signal may have occurred. No gravitational waves have been identified in data when at least two gravitational-wave observatories were operating, which covered ∼14% of this five-day window. We report the search detection efficiency for various possible gravitational-wave emission models. Considering the distance to M101 (6.7 Mpc), we derive constraints on the gravitational-wave …

The Limits Of Knowing: Determinism, Uncertainty, And What’S Beyond The Human Gaze, Xilong T. Zhang

Masters Theses

This essay traces a personal philosophical and artistic journey from rigid belief in scientific determinism to an evolving embrace of uncertainty, subjectivity, and computational perception. Raised in an atheist, scientifically grounded household in China, the author initially adopted Newtonian determinism and Laplace’s thought experiment of a fully predictable universe as guiding principles. These beliefs informed early artistic practices rooted in Constructivism, geometry, and rule-based aesthetics. However, a failed attempt to fully optimize life through deterministic control led to physical and mental collapse, prompting deeper exploration into Cartesian dualism, quantum mechanics, and the limits of reason. Through Heisenberg’s Uncertainty Principle and …

Strongly Confined Bi2se3 Quantum Dots Via Pulsed Laser Ablation In Liquids, Gregory Guisbiers, Rajendra Subedi, Burningham Burningham, Francisco Francisco Ruiz-Zepeda, Qiaohui Zhou, Xin Lu

Faculty Scholarship

Bismuth selenide (Bi2Se3) is a binary compound displaying a strong spin−orbit coupling, resulting in a narrow bulk bandgap material with a gapless metallic surface. By shrinking the size of Bi2Se3 within the strong confinement regime, its optoelectronic properties changed drastically. To achieve this goal, strongly confined Bi2Se3 quantum dots (QDs) were produced by pulsed laser ablation in liquids (PLAL). The laser used for the synthesis was a nanosecond Nd/YAG laser emitting at 1064 nm and pulsing at ∼13 mJ/pulse. The irradiation of the bulk target was performed at 1 kHz in acetone and lasted 5 min. Finally, the Bi2Se3 QDs …

Nuclear Magnetic Resonance Dynamics Of Pyrazole-Litfsi Eutectic Solvents As Promising Electrolytes, Emilia Pelegano-Titmuss, Giselle De Araujo Lima E Souza, Muhammad Zulqarnain, Ramez Elgammal, Thomas Zawodzinski, Steven Greenbaum

Undergraduate Research

Deep Eutectic Solvents (DESs) have emerged as promising candidates to replace conventional organic solvents in various technological applications due to their low vapor pressure, non-flammability, and ease of preparation at low costs. In particular, Type IV DESs, which are composed of metal salts and hydrogen bond donors, are possible replacements for lithium-ion battery electrolytes due to their potential of having high lithium transference numbers. In this study, we investigated solvents of Pyrazole and LiTFSI at varying molar ratios using Fast Field Cycling (FFC) NMR Relaxometry. Notably, the 1:2 LiTFSI: Pyrazole sample shows distinct behavior, exhibiting enhanced relaxation rates for ^{1 …}

Transformer Decoder-Enhanced Swin Unetr For Multi-Organ Semantic Segmentation On Openkbp: Improving Radiotherapy Planning Accuracy, Zainab Adnan Jwad, Israa Hadi Ali

Karbala International Journal of Modern Science

Accurate segmentation of organs-at-risk (OARs) in head and neck CT scans is crucial for radiotherapy planning. The CNN-based decoder limitation of Swin UNETR hinders its capacity to process meaningful information from multiple organ positions essential for accurate medical segmentation. The proposed Transformer Decoder-enhanced Swin UNETR model targets the OpenKBP dataset multi-organ segmentation through its dedicated design for this purpose. The model utilizes transformers along with cross-attention approaches in its decoder to improve segmentation mask outputs through analysis of extensive global information. The model gets additional feature representation power through the addition of squeeze-and-excitation (SE) blocks linked with spatial attention mechanisms …

Computational Approach: 3d-Qsar, Molecular Docking, Molecular Dynamics Simulation Investigations, Drug- Like-Ness, And Dft Score Evaluation Of A Potential Novel And Retrosynthesis Of Some Tr-H Derivatives As Streptococcus Pneumoniae Drug., Belaidi Mustapha, Tchouar Noureddine, Djelilate Mohammed, Saleh Bufarwa, Dalal K. Thbayh

Karbala International Journal of Modern Science

Streptococcus pneumoniae is the main source of hospital-acquired pneumonia and meningococcal pneumonia in children, adults, and the elderly, especially the immunocompromised. Recently, it has attracted the attention of many research studies around the world as a potential target for remediation. TR-H are considered SP antibacterial agents, as they can inhibit. To describe their mode of action and to identify new antibacterial drugs against Streptococcus pneumoniae exhibiting the TR-H scaffold, the present work included 3D-QSAR, in- silico pharmacokinetic evaluation and molecular simulation modelling of TR-H. Using an atom-based method for quantitative structure-activity relationship (QSAR) study, a comprehensive 3D-QSAR model …

A Catalytic Pathway For The Formation Of Cyanobenzene In Nitrogen-Rich Environments And The Spectroscopy Of The Reactive Intermediates, Vincent J. Esposito, Silvia Alessandrini, David Dubois, Ryan Fortenberry

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The catalytic reaction of isocyanobenzene (C₆H₅NC) with NCN⁻ produces cyanobenzene (C₆H₅NC) through various highly stable reactive intermediate species. Nitrogen-rich environments such as Titan’s atmosphere serve as favorable locations to study reaction pathways involving nitrogenated species contributing to organic growth. Formation pathways of cyanobenzene have been characterized, but none with the contribution of anions or phenyl groups. In regions with a high abundance of nitrogen anions, such as Titan’s atmosphere, reactions with species such as NCN⁻ may play a role in the formation of cyanobenzene. Highly accurate computational methods are used …

Challenging $\Lambda$Cdm: Unraveling Cosmic Distances, Dark Sector Phenomenology, And Alternative Primordial B-Mode Sources, Kylar L. Greene

Physics & Astronomy ETDs

The dominant Lambda Cold Dark Matter (LCDM) cosmological model, while remarkably successful, increasingly shows signs that it may not fully describe our Universe, as persistent tensions in expansion rates and structure formation remain unresolved. In this thesis, I challenge the LCDM paradigm using novel theoretical frameworks combined with rigorous numerical analyses. I demonstrate that the expansion-rate tension fundamentally reflects underlying distance disagreements, and that the Thomson scattering rate strongly restricts higher pre-recombination expansion rates without additional physics. Further, I present a novel cosmological model using a mirror dark sector and varying fundamental constants, revealing an observational degeneracy allowing significantly higher …

A Novel Approach To Model The Pion Structure Using Advanced Polynomial Functions, Lucas Kotz

Physics Theses and Dissertations

In the coming years, new experiments at the Electron-Ion Collider (EIC) and the Large Hadron Collider (LHC) will provide unprecedented insight into the building blocks of matter. To make the most of these opportunities, scientists must reduce uncertainties in the theoretical models that connect what we observe in experiments to what is happening inside particles like protons and pions. A critical part of these models involves describing how a particles momentum is shared among its internal components – quarks and gluons.

This work focuses on improving how we model the internal structure of the pion. We propose a new approach …

Simulating 3d Humanoid Ragdoll Physics Using Velocity Verlet Integration, Pin Constraints, And Rigid Body Collision Systems, Son D. Nguyen

Programming Theses and Dissertations

Ragdoll physics simulates realistic character collapse with physical realism by responding to environmental forces rather than using predefined animations.

Data Encoding, Compilation, And Algorithms For Quantum Machine Learning, Aviraj Sinha

Computer Science and Engineering Theses and Dissertations

Quantum computing enables new approaches to data processing, especially in quantum machine learning. Unlike classical systems, quantum data must be synthesized through operations and can exist in superposition. Encoding choices affect efficiency, noise resilience, and trainability—key factors in quantum machine learning models. This dissertation enhances quantum data encodings by extending quantum read-only memory (QROM) beyond binary representations, improving efficiency and parallelism. It introduces new compilation methods for quantum random number generators (QRNGs), supporting non-parametric distributions for post-quantum cryptography. Additionally, it explores Cayley graph-based encodings to extract spectral features for quantum machine learning.

Noise-Embedded Image Processing Based On Quantum Data Encodings, Yayu Mo

Multidisciplinary Studies Theses and Dissertations

Advancements in quantum information have significantly impacted the field of image processing, although challenges remain. Especially in the edge detection and image encoding area, distorted feature and noises would affect the further classification or super resolution tasks. In our work, we conduct researches on two stages to both evaluate the potential of Quantum-based Convolutional Structure in extracting distorted feature and further explore the effects of quantum noise channels on quantum image encodings.

In the first stage, we propose a method to extract distorted edge features by applying shallow layers in quantum convolutional neural networks (QCNN). By combining the advantages of …

The Nanograv 15 Yr Data Set: Harmonic Analysis Of The Pulsar Angular Correlations, Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Jeremy G. Baier, Paul T. Baker, Bence Bécsy, Laura Blecha, Kimberly K. Boddy, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Rand Burnette, J. Andrew Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie

Pacific Faculty Work

Pulsar timing array observations have found evidence for an isotropic gravitational-wave background with the Hellings-Downs angular correlations between pulsar pairs. This interpretation hinges on the measured shape of the angular correlations, which is predominantly quadrupolar under general relativity. Here we explore a more flexible parameterization: we expand the angular correlations into a sum of Legendre polynomials and use a Bayesian analysis to constrain their coefficients with the 15 yr pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). When including Legendre polynomials with multipoles ℓ ≥ 2, we only find a significant signal in …

Development Of Non-Precious Iron-Cobalt Alloy Catalyst For Electrocatalytic Reaction, Harsh Panchal

Electronic Theses & Dissertations

The development of a FeCo alloy catalyst with tunable Fe/Co ratios is examined to improve electrocatalytic performance in reactions like the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR). Many energy conversion devices, such as fuel cells, metal-air batteries, and water-splitting systems, depend on these interactions to function. These technologies have huge potential to meet the increasing need for hydrogen production and renewable energy sources worldwide, which are critical to attaining a sustainable energy future. When compared with noble metal-based catalysts, the FeCo alloy catalyst shows much higher catalytic activity, according to previous studies. Hydrothermal …

Zn–Assisted Synthesis Of M (Mn/Fe/Co/Ni)-N-C Catalysts For Multifunctional Electrochemical Activity, Kemila A. Chaudhary

Electronic Theses & Dissertations

The design and development of atomically dispersed M-N-C catalysts (metal (M) supported on an nitrogen-carbon (NC) matrix with high multifunctional electrocatalytic performance is desirable but proved to be very challenging. Herein, we synthesized M-N-C catalysts (M = Fe, Co, Mn, and Ni) using Zn-assisted high temperature treatment and characterized using various techniques. The prepared catalysts were tested for their electrocatalytic performance towards oxygen and hydrogen evolution reaction (OER and HER) as well as oxygen reduction reaction (ORR) in alkaline media. The results indicated that Mn-N-C catalyst showed higher performance towards both the ORR (E_1/2 = 0.90 V) and …

On Efficient Position Dependent Computation Of Radiation Near Accretion Disks, Kara Jeanette Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Accretion onto super massive black holes (SMBH) plays a vital role in explaining our observations of active galactic nuclei (AGN). One key aspect of observations of AGN is the prevalence of massive outflows which transport matter and energy away from the galactic core. These outflows are characterized by highly blueshifted absorption lines as radiation from the accretion disk is absorbed by gas which is moving toward us. Radiation pressure on spectral lines is expected to play a vital role in launching and accelerating these winds. At the other end of the spectrum of black hole masses, accretion disks in X-ray …

Explorations Of Amplified Feedback In Quantum Circuits, Maxwell B. Weiner

Dartmouth College Master’s Theses

The Josephson Traveling Wave Parametric Amplifier (TWPA) has emerged as a key technology for high-fidelity qubit readout in superconducting quantum computing. By leveraging the nonlinear inductance of an array of Josephson Junctions, the TWPA enables broadband, near-quantum-limited amplification with minimal added noise, significantly improving the signal-to-noise ratio in qubit measurements. Unlike traditional resonant parametric amplifiers, which suffer from bandwidth constraints, the traveling wave design of the TWPA allows for wideband operation, making it particularly suited for multiplexed readout of both simple qubits and large-scale quantum processors.

In this thesis, we explore how the TWPA can be integrated into a feedback …

High Dynamic Range Actively Quenched Silicon-Germanium Single-Photon Avalanche Diodes, Abraham Castaneda

UNLV Theses, Dissertations, Professional Papers, and Capstones

Single-photon avalanche diodes (SPADs) are solid-state devices capable of providing large current pulses in the milliampere range in response to incident photons. The large gain inherent to SPADs makes them a popular technology for photon-counting applications, but their operation can be hindered by long recharge times, which necessitates the use of active quenching to reduce dead times and increase detection rates. For the prompt gamma/neutron radiation experiments conducted at the Nevada National Security Site, photomultiplier tubes (PMTs) have been the primary photodetector of choice, but their continued use is expected to dwindle as it becomes increasingly difficult to source quality …

Extending The Bridge Connecting Chiral Lagrangians And Qcd Gaussian Sum Rules For Low-Energy Hadronic Physics, Amir H. Fariborz, Jason N.E. Ho, T. G. Steele

Faculty Work Comprehensive List

It has previously been demonstrated that the mesonic fields in chiral Lagrangians can be related to the quark-level operators of QCD sum-rules via energy-independent (constant) scale factor matrices constrained by chiral symmetry. This leads to universal scale factors for each type of chiral nonet related to quark-antiquark (𝑞⁢¯𝑞) operators and four-quark (𝑞⁢𝑞⁢¯𝑞⁢¯𝑞) operators. Motivated by these successful demonstrations of scale-factor universality for the 𝐾*0 isodoublet and 𝑎0 isotriplet scalar mesons, a revised Gaussian QCD sum rule methodology is developed that enables the extension to higher-dimensional isospin sectors, including the possibility of mixing with glueball components. Moreover, to extract nonperturbative information …

Design Of Silicon Grating Metasurfaces For Beam Deflecting In Solid-State Light Detecting And Ranging (Lidar), Matthew Baker

Honors Program Theses and Projects

My thesis begins with an overview of LiDAR (Light Detecting and Ranging) and theory for electromagnetic wave propagation. We establish problems that arise from the use of external beam steering components in LiDAR systems. As a possible solution, we introduce the concept of a metasurface with sub-wavelength dimensions. Grating metasurfaces utilize periodicity to change the phase gradient along a surface. Using a row of posts on a substrate, we can confine light towards one side of a structure, deflecting at angles towards a maximum angle determined by the structure’s geometry. These metasurfaces are small enough to be directly incorporated onto …

Quasi-Normal Modes Of Extended Uncertainty Principle Kerr Black Holes, Ava Hoeger, Jonas Mureika

Honors Thesis

The current understanding of gravity is shaped largely by Albert Einstein’s theory of General Relativity. This theory is highly successful at predicting phenomenon on macroscopic scales, but it faces unphysical singularities at quantum scales. This thesis will explore the possibility of combining General Relativity with quantum mechanics through the Extended Uncertainty Principle (EUP), which provides a new, fundamental length scale correction to the Heisenberg Uncertainty Principle. This allows for quantum gravity effects at macroscopic scales, which will be examined through Kerr black holes with event horizons on the order of . These black holes are rotating and electrically neutral, and …

Examining The Accuracy Of The Omni Data In Representing Geomagnetic Storm Observations Near Earth And The Effect On Global Modeling, James T. Davis

2025 Spring Honors Capstone Projects - Archive

The accuracy of OMNI dataset being propagated to bow shock nose and used to represent geomagnetic storms is a known issue. Inaccuracies of this data bring erroneous results in scientific endeavors therefore establishing the importance of accuracy and consistency. This case study examines the accuracy of the OMNI data and data near-Earth in representing geomagnetic storms with different drivers on global simulations. This research will include examples of global magnetosphere simulations, such as SWMF, driven with two storms driven by coronal mass ejections, and one driven by a high-speed stream using OMNI data and data near-Earth to illustrate potential variations …

Quasiparticle Poisoning And Mitigation Strategies In Superconducting Qubits, Clayton Larson

Dissertations - ALL

Quantum computers promise to solve currently intractable problems of great interest for a diverse range of applications. For a quantum computer to solve these problems, it must handle occasional errors with quantum error correction, which distributes the quantum information across many physical qubits, increasing resilience. A promising technology for implementing such a system uses superconducting circuits as physical qubits. Standard quantum error correction schemes can accommodate random, local errors, but errors that are correlated across multiple qubits are fatal. Correlated errors can arise from ionizing radiation impacting the device substrate, which creates free charge that can be sensed by the …

Geometry And Mechanical Response Of Twisted Thin Tubes, Pan Dong

Dissertations - ALL

Nature provides many examples of thin sheets and shells, from flower petals to graphene sheets. Such materials can exhibit complex deformations such as creases, folds and wrinkles, particularly in thin, flexible structures like cylindrical shells and ribbons. Here we investigate the geometric transformation and mechanical response of a twisted thin tube, which is made from a thin polymer sheet. In Chapter 2, an interesting "locking behavior" was found in a thin cylindrical shell. After an initial compression, the shell can be twisted with little resistance until it reaches a “locking angle”, which coincides with the appearance of an ordered wrinkle …

Measurements And Modeling Of Phonon-Mediated Quasiparticle Poisoning In Superconducting Qubit Arrays, Eric Yelton

Dissertations - ALL

The realization of a quantum computer that can correct for random errors on its constituent quantum bits, or qubits, is one of the primary goals in the quantum information science community. One of the leading protocols to correct these errors on a quantum processor relies on nearest-neighbor coupling of an array of physical qubits that act collectively as a single logical qubit. Superconducting circuits are a leading implementation of a physical qubit and have been used in some of the first demonstrations of this error correction scheme. A key assumption of this protocol is that errors on the physical qubits …