Physics Commons^™

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

Frustration And Functionality : Geometry And Topology In Mechanical Metamaterials, Sourav Roy

Dissertations - ALL

This dissertation is concerned with a study of the effect of geometry in complex few body mechanical systems. The problems that we set out to solve lie on the interface of soft condensed matter physics, geometry and topology. In the first problem, I developed an effective elasticity theory of thin mechanical metamaterial sheets. This work explored the elastic response of thin metamaterial sheets draped on a uniformly and weakly curved substrate. The model spells out an elegant screening law that shows that a metamaterial alleviates elastic stresses by actuating the soft modes accessible to it. In the second problem, we …

Deformations Of Thin Membranes In Incompatible Geometries And Interactions In Mechanical Hysteron Systems, Zachariah Schrecengost

Dissertations - ALL

Soft reconfigurable systems exhibit behaviors which are highly dependent on their geometries. Thin membranes can deform in a myriad of ways as they navigate geometries different from their own in an energy efficient manner. Behaviors in mechanical hysteron systems are influenced by the geometry of the interactions and global driving. This dissertation focuses on two different types of systems which are governed in part by their geometries: thin membranes in geometrically incompatible configurations and interacting mechanical hysterons. A thin membrane forced into a conflicting geometry with an incompatible metric will deform in highly non-trivial ways. These deformations are an attempt …

Multi-Modal Mri For The Pre-Clinical Evaluation Of Hiv-Linked Changes In The Central Nervous System, Gabriel Gauthier

Theses & Dissertations

Though the inception of anti-retroviral therapy (ART) has fundamentally changed the life expectancy of human immunodeficiency virus (HIV) patients, accessibility and outcomes vary enormously along demographic lines. Even for people living with HIV (PLWH) with perfect access and adherence to anti-retroviral drugs (ARVs), modern treatment plans are fundamentally unable to secure complete viral remission for patients. The cause of this perpetual infection is the persistence of viral reservoirs in the central nervous system (CNS), hidden beyond the reach of modern ARVs, leaving patients to deal with lifelong medication side-effects and risks of developing HIV-associated neurodegenerative disorders (HAND). Despite improving outcomes …

Intrinsic And Extrinsic Drivers Of Bioaerosol Decay: Investigating Pathogen Stability Of Bacteriophage Ms2, Sin Nombre Virus, And Sars-Cov-2 In Simulated Environments, Elizabeth A. Klug

Theses & Dissertations

The threat posed by a virus as a bioaerosol depends largely on its stability under various environmental conditions (relative humidity (RH), sunlight, ozone, etc.). This stability is typically studied through aerosol decay—how the virus' viability changes over time when exposed environmental conditions. The Goldberg rotating drum, a widely used tool for studying bioaerosols, has been the basis of such research (Goldberg et al., 1958). However, it has significant limitations, including an inability to measure initial pathogen infectivity loss and the use of small sample volumes. Additionally, it does not answer the question of what intrinsic factors (lipids, proteins, nucleic acids) …

Creasing In Thick Hemispherical Shells As A Model For Foveal Formation, Indigo Skye Peppard

Undergraduate Honors Theses

This research experimentally investigates creasing behavior on the inner surface of hemispherical shells with the ultimate goal of modelling the formation of the foveal pit, a sharp surface deformation present in the retina of the eye of many animals. Creasing is a phenomenon observed in hyperelastic materials and is characterized by sharply localized surface deformations that appear at ~35% compressive strain. The foveal pits of anoles (small iguanian lizards) are funnel-shaped and resemble creases when cut along the central axis. Furthermore, during foveal pit formation the anole eye contracts around 35% along this same axis. Given these similarities we believe …

Direct Computations Of Spatially Resolved Viscoelastic Moduli Of Biomolecular Condensates, Liwen Gu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Biomolecular condensates are viscoelastic materials formed by liquid-liquid phase separations (LLPS) of biopolymers. In this study, we develop a modified graph Laplacian-based collective model to characterize viscoelastic heterogeneity within condensates based on results of lattice-based Metropolis Monte Carlo (MMC) simulations. By integrating random graph models and simulations of A1-LCD, a type of intrinsically disordered protein, we examine how network topology influences storage modulus, loss modulus, crossover frequency, and relaxation time spectra. Our results reveal a strong correlation between topological features and mechanical response, with the condensate interior exhibiting higher stiffness and faster relaxation than the interface. The relaxation spectra provide …

Simplicity From Complexity: Sensing High-Dimensional Fluctuations Via Regulatory Network, Optimality In Allocating Cellular Resources, And Recovering Functional Groups Via Data-Driven Methods, Fang Yu

Arts & Sciences Graduate Student Theses and Dissertations

Biological systems must navigate dynamic and complex environments while operating under constraints such as limited molecular resources, biochemical noise, and structural trade-offs. This dissertation investigates three distinct cases in which biological systems allocate resources and process information efficiently, revealing emergent simplicity from underlying complexity. The first study develops a generalized end-product inhibition model with cross-talk and an excess of regulators, providing a proof-of-principle that simple biochemical circuits could, in principle, dynamically adjust their responsiveness to high-dimensional environmental variation. This result highlights how such circuits may allow adaptive filtering of both dominant and subdominant fluctuation modes. The second study, conducted in …

Topological And Optical Properties Of Two-Dimensional Materials, Haonan Wang

Arts & Sciences Graduate Student Theses and Dissertations

Recent advances in condensed matter physics have revealed a wide range of novel quantum phenomena in two-dimensional (2D) materials. The discovery of unique topological, magnetic, and optical properties in solids has greatly expanded our understanding of quantum phases in electronic structures. As more material systems are proposed theoretically and realized experimentally, our research focuses on uncovering and explaining these phenomena through effective models and first-principles calculations. First, we explore topological mosaic patterns in moiré superlattices—structures composed of periodic, spatially distinct domains, each with different topological properties. These domains give rise to periodic edge states along domain walls. We explore the …

X-Ray Polarization Of Accreting Stellar-Mass Black Holes Through Accretion States, Nicole Rodriguez Cavero

Arts & Sciences Graduate Student Theses and Dissertations

In recent years, X-ray polarization has opened up a new window into our understanding of astrophysical sources. Among them are accreting stellar-mass black holes, which play a key role in testing the behavior of matter in extreme gravitational environments. These sources can be observed in different states of the accretion cycle, predominantly in the soft and hard states. Every state is dominated by a combination of thermal disk, coronal, or reflected emission—each type containing different information about the environment around the black hole that can be understood through polarization. Polarimeters such as the Imaging X-ray Polarimetry Explorer and XL-Calibur allow …

Computational Design Of Potent Sirna For Braf Oncogene Silencing For Enhancing Cancer Therapy, Muhammad Hermawan Widyananda, Ricadonna Raissa

Karbala International Journal of Modern Science

The discovery of oncogenic BRAF mutations has prompted the development of inhibitors, yet resistance remains widespread. A more effective strategy involves targeting BRAF mRNA with siRNA to overcome resistance to BRAF inhibitors. This study aims to design potent siRNA for BRAF oncogene silencing using a computational approach. The full coding sequence of BRAF was retrieved from the NCBI database and potential siRNAs were predicted using the Ui-Tei, Reynolds, and Amarzguioui rules. Identified siRNAs were further analyzed using various prediction systems and parameters, including their interaction with the hAgo2 protein. The results identified that seven siRNAs (siRNA 23, siRNA 24, siRNA …

Nonthermalizing Dynamics Of Interacting Rydberg Atoms, Nicolaus A. Chlanda

Physics and Astronomy Honors Papers

An isolated system of ultracold Rydberg atoms can come to equilibrium by exchanging energy through dipole-dipole interactions. In our experiment, a static electric field of a few V/cm shifts the energy levels of the atoms, so that the energy levels are nearly degenerate at zero field and fan out with increasing field to form a manifold. We excite atoms to energy levels near the center of the manifold, where the spacing is nearly harmonic. We allow them to interact for a few microseconds, by which time the population of each energy level has reached a steady state. The population is …

Experimental Evaluation Of Resource Allocation To Organelles In Eukaryotic Cells, Ronan Hanley

Senior Honors Papers / Undergraduate Theses

Among the hallmarks of the eukaryotic cell is its organization into spatially defined sub-compartments known as organelles. Organelles provide optimized environments for otherwise incompatible biochemical reactions within the cell. It has been shown that there is significant variation in the properties of organelles in a cell, and that cells have access to a limited pool of resources that they can allocate to organelles. This begs the question: by what principles do cells dictate how resources are allocated? To begin to explore this question, we look at resource allocation in S. cerevisiaefrom two perspectives. First, we use a combination of …

Characterization Of A Magnetically Contained Hot Filament Plasma Source With A Wide-Sweeping Langmuir Probe, Jonas Rowan

Doctoral Dissertations and Master's Theses

Ionospheric plasma research in the Space and Atmospheric Instrumentation Laboratory’s Space Plasma Chamber has been hindered by the lack of a suitable plasma diagnostic instrument and understanding of its hot-filament plasma source. This thesis describes efforts made to remedy both problems. A wide-range Sweeping Langmuir Probe was developed with a ±35 V sweeping range to fully analyze ion and electron saturation regions in the entire IV curve. A method was derived to estimate the chamber source’s filament temperatures. The new Langmuir probe was integrated into a refurbished automated system designed in Python to measure plasma parameters for various chamber conditions, …

Treatment Wastewater Of Oil Refinery By Fe2o3 Nps Produce By The Novel Alishewanella Jeotgali Strain Haq8., Hawraa Qays Al-Assdy, Wijdan Hussein Al-Tamimi, Asia Fadhile Almansoory

Karbala International Journal of Modern Science

Metal oxide nanoparticles like iron oxide (Fe₂O₃) exhibit strong reactivity and photolytic features in wastewater treatment and serve as an effective adsorbent for water purification due to its substantial surface area and affinity for different functionalized groups. Iron oxide nanoparticles) IONPs) are currently applied to treat oil-contaminated water. Fe₂O₃NPs were produced using an extracellular approach utilizing the Alishewanella jeotgali strain HAQ8. IONPs were characterized using UV-vis, FT-IR, XRD, AFM, SEM-EDX, and Zeta potential. λ max for the synthesized nanoparticles observed at (358) nm. The bands at 485 cm⁻¹ in the FT-IR spectrum confirmed the formation of …

First-Principles Studies Of Excited-State Properties In Large-Scale Systems, Du Li

Arts & Sciences Graduate Student Theses and Dissertations

Density Functional Theory (DFT) is widely used as a powerful tool for studying the electronic structure of materials. However, due to the local or semilocal nature of exchange-correlation functionals, such as the local density approximation and generalized gradient approximation functional, DFT often underestimates the electronic band gap. Many-body perturbation theory (MBPT) within the GW approximation provides more accurate quasiparticle energies calculation by incorporating many-electron screening effects. Additionally, solving the Bethe-Salpeter Equation (BSE) allows for a detailed analysis of excitonic effects in optical spectra. Despite their accuracy, GW-BSE calculations are computationally expensive, particularly for large-scale systems such as defects and substrate-supported …

First-Principles Studies Of Electrical Polarization Effects In Ferroelectrics, Antiferroelectrics And Defects, Louis Alaerts

Dartmouth College Ph.D Dissertations

Over the last few decades, density functional theory (DFT) has emerged as a formidable tool in the field of computational material science. Not only has it become a complementary method approach to experiments by rationalizing the many complex properties of materials but its formidable predictive power can also be used to identify the most promising candidates for specific applications. Point defects in semiconductors have become an important platform for the development of quantum networks due to their ability to act as spin-photon interfaces. Spectral diffusion, the broadening of the optical emission line, can significantly impact the performance of these defect-based …

The Distribution Of Ultrahigh-Energy Cosmic Rays Along The Supergalactic Plane Measured At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, A. Puyleart, Et. Al

Michigan Tech Publications

Ultrahigh-energy cosmic rays are known to be mainly of extragalactic origin, and their propagation is limited by energy losses, so their arrival directions are expected to correlate with the large-scale structure of the local Universe. In this work, we investigate the possible presence of intermediate-scale excesses in the flux of the most energetic cosmic rays from the direction of the supergalactic plane region using events with energies above 20 EeV recorded with the surface detector array of the Pierre Auger Observatory up to 2022 December 31, with a total exposure of 135,000 km2 sr yr. The strongest indication for an …

Theoretical Proof Of And Proposed Experimental Search For The Ground Triplet State Of A Wigner-Regime Two-Electron ‘Artificial Atom’ In A Magnetic Field, Marlina Slamet, Viraht Sahni

Publications and Research

It is experimentally established that there is no ground triplet state of the natural He atom. There is also no exact analytical solution to the Schrödinger equation corresponding to this state. For a two-dimensional two-electron ‘artificial atom’ or a semiconductor quantum dot in a magnetic field, as described by the Schrödinger–Pauli equation, we provide theoretical proof of the existence of a ground triplet state by deriving an exact analytical correlated wave function solution to the equation. The state exists in the Wigner high-electron-correlation regime. We further explain that the solution satisfies all requisite symmetry and electron coalescence constraints of …