Physics Commons^™

Differential Elliptic Flow Analysis Of Hadrons With Different Wuark Content In Simulated Pp Collisions, Elhussein Osama

Theses and Dissertations

According to current physics theories, it is assumed that in the first microsecond after the big bang, the universe was in a state of matter called Quark-Gluon Plasma (QGP), where the fundamental consistent of matters (quarks and leptons), were highly energetic, and floating around freely. Searching for such phase of matter; as the possible earliest signatures after the big bang, and among many other interesting experimental measurements, the jet quenching and elliptic flow are the most important ones, in the heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) experiments.

The azimuthal anisotropy …

Characterization Of Isomeric States In Neutron-Rich Nuclei Approaching N = 28, Timilehin Hezekiah Ogunbeku

Theses and Dissertations

The investigation of isomeric states in neutron-rich nuclei provides useful insights into the underlying nuclear configurations, and understanding their occurrence along an isotopic chain can inform about shell evolution. Recent studies on neutron-rich Si isotopes near the magic number N = 20 and approaching N = 28 have revealed the presence of low-lying states with intruder configurations, resulting from multiple-particle, multiple-hole excitations across closed shell gaps. The characterization of these states involves measuring their half-lives and transition probabilities.

In this study, a new low-energy (7/2⁻₁) isomer at 68 keV in ³⁷Si was accessed via beta decay …

Biomolecular Function From Structural Snapshots, Roshanak Etemadpour

Theses and Dissertations

Biological molecules can assume a continuous range of conformations during function. Near equilibrium, the Boltzmann relation connects a particular conformation's free energy to the conformation's occupation probability, thus giving rise to one or more energy landscapes. Biomolecular function proceeds along minimum-energy pathways on such landscapes. Consequently, a comprehensive understanding of biomolecular function often involves the determination of the free-energy landscapes and the identification of functionally relevant minimum-energy conformational paths on these landscapes. Specific techniques are necessary to determine continuous conformational spectra and identify functionally relevant conformational trajectories from a collection of raw single-particle snapshots from, e.g. cryogenic electron microscopy (cryo-EM) …

Analyzing The Effects Of Ultrafast Laser Processing On Mechanical Properties Of 3d-Printed Pla Parts, Darshan Pramodbhai Yadav

Theses and Dissertations

Recent advances in additive manufacturing technologies have already led to wide-scale adoption of 3D-printed parts in various industries. The expansion in choice of materials that can be processed, particularly using Fused Deposition Modeling (FDM), and the steady advancements in dimensional accuracy control have extended the range of applications far beyond rapid prototyping. However, additive manufacturing still has considerable limitations compared to traditional and subtractive manufacturing processes. This work addresses limitations associated with the as-deposited surface roughness of 3D-printed parts. The effects of roughness-induced stress concentrations were studied on ultimate tensile strength and fatigue life. The samples were manufactured using a …

Direct Measurement Of The 114cd(��, ��)115cd Cross Section In The 1 Ev To 300 Kev Energy Range, Kofi Tutu Addo Assumin-Gyimah

Theses and Dissertations

The large thermal cross section of cadmium makes it ideal for many practical applications where screening of thermal neutrons is desired. For example, in non-destructive assay techniques, or for astrophysical studies of the s-process. All such applications require precise knowledge of the neutron-capture cross section on cadmium. Although there are some data on neutron-capture cross sections particularly at thermal energies and at energies relevant for astrophysics, there is very little data at most other energies. Further, the evaluated cross sections from the ENDF and JENDL databases disagree at high energies. Therefore, there is a critical need for precise knowledge of …

Synthesis, Characterization, And Simulation Of Two-Dimensional Materials, Lawrence Hudy

Theses and Dissertations

ABSTRACT

SYNTHESIS, CHARACTERIZATION, AND SIMULATION OF TWO-DIMENSIONAL MATERIALS

by

Lawrence Hudy

The University of Wisconsin-Milwaukee, 2023Under the Supervision of Professor Michael Weinert

This dissertation focuses on my journey through many aspects of surface science leading to the first principles investigation of transition metal dichalcogenides studying the impact of defects, twist, and decreasing interlayer separation to probe their effect on the electronic properties of these materials. My journey started out learning many aspects of material science such as methods for material synthesis and characterization but later ended on simulation of material properties using density functional theory. In the first experiments, we …

A Novel Technique To Solve Fractional Differential Equations Using Fractional-Order B-Polynomial Basis Set, Md Habibur Rahman

Theses and Dissertations

This thesis uses B-Polynomial bases to solve both one-dimensional and multi-dimensional linear and nonlinear partial differential equations and linear and nonlinear fractional differential equations. The approach involves constructing an operational matrix from the terms of these equations using Caputo's fractional derivative of fractional B-polynomials. This leads to a semi-analytical solution derived from a matrix equation, and the results obtained using this method are compared to analytical and numerical solutions presented by other authors. The method is shown to be effective in calculating approximate solutions for various differential equations and provides a higher accuracy level than finite difference methods. This technique …

Two-Dimensional Crystal Phases Of Graphene Monoxide & Interaction Of Lithium With Graphene Monoxide, Danylo Radevych

Theses and Dissertations

This work explores the possible existence, properties, and potential applications of different polytypes of graphene monoxide (GmO) - two-dimensional crystalline monolayers composed of equal numbers of O and C atoms. In addition to previously experimentally discovered and theoretically modeled α phase, prediction and discovery of the second phase - β-GmO - is reported along with evaluation of six other possible phases. Structural parameters, electronic and mechanical properties of all the phases, including α-GmO, are determined using density functional calculations and compared. It is suggested that multiple phases of GmO can co-exist in the same composite, and developing a synthesis process …

Construction Of Zinc Oxide And Magnesium Oxide Heterostructures By Atomic Layer Deposition, Netra Sharma

Theses and Dissertations

Zinc oxide (ZnO) has gained wide technological interest due to its direct bandgap of ~3.37 eV and high exciton binding energy of ~60 meV and has exhibited promise for numerous electronics and opto-electronics applications. ZnO can also be alloyed with materials like magnesium oxide (MgO) to tailor the bandgap. Such heterostructures (Zn, Mg)O can be used in optoelectronic devices like quantum well lasers, photodetectors, etc.In this work, we studied the physical properties of zinc oxide (ZnO), magnesium oxide (MgO) and the heterostructures of zinc and magnesium oxide (Zn,Mg)O grown by atomic layer deposition (ALD) using a homemade viscous flow type …

Topological Superconductors And Dark Matter Searches In Gravitational Wave Interferometers, Han Gyeol Suh

Theses and Dissertations

This work is comprised of research in two areas: superconductors and gravitational waves.

Superconductors have led to novel fundamental discoveries, including new topological states. These states are robust, in that they are not altered by common changes to their environment. Here, I will introduce three studies focused on topological properties of various superconductors. First, newly proposed even-parity superconducting state in Sr$_2$RuO$_4$ introduces the emergence of topologically protected Bogoliubov Fermi surfaces. Next, I will discuss topological bands and odd-parity superconductivity in UTe$_2$, which suggest Weyl nodes and their potential topological properties. Lastly, anomalous pseudospin in non-symmorphic materials shows different symmetry properties …

A Convolutional Neural Network Based Approach To Study The Gravitational Waves From Core-Collapse Supernovae In Ligo's Third Observation Run: Detection Efficiency And Parameter Estimation, Bhawana Sedhai

Theses and Dissertations

Core-Collapse Supernova (CCSN) is one of the most anticipated sources of Gravitational Waves (GW) arriving at the advanced LIGO detectors during the fourth observation run (O4). CCSN are rare, weak and unmodeled having a very low rate of occurrence in our galaxy (estimated 2 per century). Thus, detection of GW from CCSN is a challenging problem. An analysis pipeline used in this study is Multi-Layer Signal Enhancement with cWB and CNN or MuLaSEcC that combines Machine Learning methods with a network of Gravitational Wave detectors to identify and reconstruct signals from core collapse supernovae, while minimizing false alarms through the …

Analyzing The On Source Window Of Supernova Sn2019ejj With A Multi Layered Signal Enhancement Algorithm With Coherent Waveburst And A Convolutional Neural Network, Michael Gale Benjamin

Theses and Dissertations

Core collapse supernovae (CCSN) are highly anticipated sources of gravitational waves during the fourth observation run (O4). CCSN signals are weak and unmodeled and the rate of occurrence in our galaxy is very low. Because of this, they provide a greater challenge to detect than previously detected GW sources. CCSN simulations are used to test the detection pipeline in the event a CCSN is detected. CCSN GW signals are often indistinguishable from the noise sources present in GW data. We present a multi layered signal enhancement pipeline which we have applied Machine Learning (ML) techniques. We have used a Convolutional …

Measurement Of The Total Cross-Section Of Muon Neutrino Charged-Current Coherent Pion Production In Nova Near Detector, Kuruppumullage Don Chatura Dilshan Kuruppu

Theses and Dissertations

Charged Current (CC) coherent neutrino-nucleus pion production is characterized by small momentum transferred to the nucleus, which is left in its ground state. Despite the relatively large uncertainties on the production cross-section, coherent production of mesons by neutrinos represents an important process, as it can shed light on the structure of the weak current and can also constitute a potential source of background for modern neutrino oscillation experiments and searches for Beyond Standard Model (BSM) physics. This Ph.D. thesis presents a new measurement of CC coherent pion production in the NOvA near detector at the Fermi National Accelerator Laboratory (Fermilab). …

Yield Extraction For The Γd → Λ X Reaction, K H P Nishadi Hasarangi Silva

Theses and Dissertations

Improving and adding new experimental measurements of hyperon-nucleon (YN) and hyperon-deuteron (Yd) cross sections is an active area in nuclear physics research. Scientists use such cross-section data to understand the composition of neutron stars and develop a comprehensive picture of the baryon-baryon interaction. Using high luminosity photon beam incident on a long liquid deuterium target and the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (JLab), a sample of hyperon-deuteron elastic scattering events was previously identified. The E06-103 (g13) experiment was originally designed to address the scarcity of experimental data on hyperon photoproduction off the neutron …

Pairing And Rotation-Induced Nuclear Exotica In Covariant Density Functional Theory, Saja Teeti

Theses and Dissertations

Covariant density functional theory (CDFT) is one of the modern theoretical tools for describing the nuclear structure physics of finite nuclei. Its performance is defined by underlying covariant energy density functionals (CEDFs). In this dissertation and within the framework of the CDFT, different physical properties of the ground and the excited states of rotating and non-rotating nuclei have been investigated.

A systematic global investigation of pairing properties based on all available experimental data on pairing indicators has been performed for the first time in the framework of covariant density functional theory. It is based on separable pairing interaction of Ref.\ …

Monolithic Multiphysics Simulation Of Hypersonic Aerothermoelasticity Using A Hybridized Discontinuous Galerkin Method, William Paul England

Theses and Dissertations

This work presents implementation of a hybridized discontinuous Galerkin (DG) method for robust simulation of the hypersonic aerothermoelastic multiphysics system. Simulation of hypersonic vehicles requires accurate resolution of complex multiphysics interactions including the effects of high-speed turbulent flow, extreme heating, and vehicle deformation due to considerable pressure loads and thermal stresses. However, the state-of-the-art procedures for hypersonic aerothermoelasticity are comprised of low-fidelity approaches and partitioned coupling schemes. These approaches preclude robust design and analysis of hypersonic vehicles for a number of reasons. First, low-fidelity approaches limit their application to simple geometries and lack the ability to capture small scale flow …

Determination Of Effective Index Of Refraction Of Structured Materials (Photonic Crystals), Md Arafat Hossain

Theses and Dissertations

Photonic crystals have been widely studied by researchers due to their ability to control light propagation in all spatial directions. For example, 2D photonic crystals can be made of dielectric rods arranged in a square lattice. When light propagates through 2D photonic crystals, it experiences multiple scatterings by the crystal centers. The superposition of all scattered waves forms the transmitted field largely dependent upon the effective index of refraction of the structured material. We propose a method to determine the effective index of refraction through such materials with the Finite-Difference Time-Domain (FDTD) model. We set up the interface of two …

Gamma Calibration Of Scintillators For The Muon Scattering Experiment, Anne Gloria Flannery

Theses and Dissertations

The MUon Scattering Experiment (MUSE) at the Paul Scherrer Institute seeks to measure the muon-proton and electron-proton elastic cross-sections in the same experiment by measuring the scattering angle of particles from a 115-160 MeV beam onto a liquid hydrogen target. The timing detectors, as well as several of other detectors in the experiment, are plastic scintillators. This document discusses a method for the energy calibration, using ²⁰⁸Tl, ²²Na, and 88Y sources, signal attenuation, and hit-position reconstructions of various timing detectors, as well as their function in the experiment as a whole. This method involves first attaining the pulse-height …

A Study Of Single Molecule Detection With Graphene Hall Bars, Kenneth Stephen Stephenson

Theses and Dissertations

In 2007, detection of individual molecules with a solid-state gas sensor was reported for first time by Schedin et al. where they used micromechanically-cleaved graphene for their sensing material, which exhibits isotropic and homogeneous conduction [1]. However, despite the novelty and popularity of their work, it has never been repeated. Further, we found their associated calculations to be self-inconsistent by a factor of 103 . So, hoping to account for and resolve this discrepancy, we outline the plan we had to reproduce their experiment. We also justify any substantial modifications, particularly our choice to use epitaxial graphene instead. Then, we …

Muon Intensity Measurement With The Majorana Demonstrator, Franklin Michael Adams Jr.

Theses and Dissertations

The Majorana Demonstrator (MJD) is a shielded radiation detection system located a mile underground at the Sanford Underground Research Facility (SURF) in South Dakota. The system aims to detect the theorized, rare process of neutrinoless double-beta decay. The Demonstrator utilizes an array of scintillating acrylic detectors to veto any signals induced by earth-penetrating cosmogenic muons and reach background levels necessary for the detection of neutrinoless double-beta decay. Utilizing the data collected by the muon veto system, an analysis has been done to determine the differential muon intensity. The complex geometry of the interlacing detector panels requires the use of Monte …

Sensitivity Of The Cupid Experiment To Bragg-Primakoff Conversion Of Solar Axions And Alps, Kevin P. Wilson

Theses and Dissertations

The author reports in this dissertation on the application of a technique to use bolometer detector arrays, such as those of the CUORE experiment and its proposed upgrade CUPID, to search for 14.4 keV Solar axions arising from an M1 nuclear transition of thermally excited ⁵⁷Fe in the Solar core. Density functional theory calculations performed using QU A N T U M ESPRESSO for Li₂MoO₄ enable the computation of a time-dependent axionto-photon conversion rate in the bolometer crystals. These calculations predict that the proposed CUPID detector will be sensitive to Solar axions or axion-like particles that …

Azimuthal Anisotropy Of Different Quark-Flavored Particles In High Energy "Simulated" Proton-Proton Collisions, Mahmoud Rateb

Theses and Dissertations

Anisotropic flow in high energy heavy-ion collisions is taken as a key evidence for the formation of QGP for brief seconds right after the collisions. Hydrodynamic models including QGP formation are accurate at predicting the azimuthal anisotropy of the produced particles at low transverse momenta. At high momenta however, hydrodynamic models predict no azimuthal anisotropy for particles of different masses and quark-flavors; the logic being that because of their high momenta, the particles pass through the media without having any time to have any reactivity. This is contrary to results from experiments where measurements of particles of different quark flavors …

Using Dielectric Scatters To Selectively Excite Embedded Eigenstates In Cavity Resonators, Olugbenga Joshua Gbidi

Theses and Dissertations

Bound states in the continuum (BICs) are waves that remain in the continuous spectrum of radiating waves that carry energy, however, still localized within the spectrum. BICs, also embedded eigenmodes, exhibit high quality factors that have been observed in optical and acoustic waveguides, photonic structures, and other material systems. Presently, there are limited means to select these BICs in terms of the quality factor and their excitation. In this work, we show that a different type of BIC, Quasi-BICs (Q-BICs), in open resonators can have their quality attuned by introducing embedded scatters. Using microwave cavities and dielectric scatters as an …

Using Superatomic Clusters And Charge Transfer Ligands To Control Electronic Characteristics Of Phosphorene Nanoribbons And Phosphorene Monolayer, Ryan Lambert

Theses and Dissertations

Phosphorene is a two-dimensional electron poor p-type semiconductor with high carrier mobility and great promise for applications in electronics and optoelectronics. As the main theme in this dissertation, the following work represents different investigations of various electronic properties associated with phosphorene. Most notable are the findings on charge transfer doping with metal-chalcogenide superatoms which displays novel control of the two most important properties of a semiconductor – the band gap energy and the nature of carriers. By tuning the width of the gap and p-/n-type character of conduction, we gain control over a material’s capacity to play a certain role …

Innovations In Drop Shape Analysis Using Deep Learning And Solving The Young-Laplace Equation For An Axisymmetric Pendant Drop, Andres P. Hyer

Theses and Dissertations

Axisymmetric Drop Shape Analysis (ADSA) is a technique commonly used to determine surface or interfacial tension. Applications of traditional ASDA methods to process analytical technologies are limited by computational speed and image quality. Here, we address these limitations using a novel machine learning approach to analysis. With a convolutional neural network (CNN), we were able to achieve an experimental fit precision of (+/-) 0.122 mN/m in predicting the surface tension of drop images at a rate of 1.5 ms^-1 versus 7.7 s^-1, which is more than 5,000 times faster than the traditional method. The results are validated on real images …

Mechanisms Of Emulsion Destabilization: An Investigation Of Surfactant, Stabilizer, And Detergent Based Formulations Using Diffusing Wave Spectroscopy, Jordan N. Nowaczyk

Theses and Dissertations

Conventional approaches for studying emulsions, such as microscopy and macroscopic phase tracking, present challenges when it comes to establishing detailed mechanistic descriptions of the impact of emulsifier and stabilizer additives. Additionally, while a combination of sizing methods and macroscopic phase tracking can provide insights into droplet size changes and concentration, the use of multiple measurements can be cumbersome and error-prone. It is the focus of this work, to present a new method for studying water in oil (W/O) emulsions that involves using diffusing wave spectroscopy (DWS) to examine the impact of three different surface stabilizing additives at varying concentrations. By …

Molecular Insights Into The Redox Of Atmospheric Mercury Through Laser Spectroscopy, Rongrong Wu Cohen

Theses and Dissertations

The widespread pollution of mercury motivates research into its atmospheric chemistry and transport. Gaseous elemental mercury (Hg(0)) dominates mercury emission to the atmosphere, but the rate of its oxidation to mercury compound (Hg(II)) plays a significant role in controlling where and when mercury deposits to ecosystems. Atomic bromine is regarded as the main oxidant for Hg(0) oxidation, known to initiate the oxidation via a two-step process in the atmosphere – formation of BrHg (R1) and subsequent reactions of BrHg with abundant free radicals Y, i.e., NO2, HOO, etc. (R2), where the reaction of BrHg +Y could also lead to the …

Precise Measurement Of The Nuclear Dependence Of The Emc Effect In Light Nuclei, Abishek Karki, Abishek Karki

Theses and Dissertations

Measurements of inclusive electron scattering cross-section ratios from light nuclei over a wide range of the Björken �� (0.3 < �� < 1) up to �� 2 = 8.3 GeV² were made as part of experiment E10-10-008, which was conducted in Hall C at the Thomas Jefferson National Accelerator Facility. The measurements were performed using a beam energy of 10.602 GeV and an average beam current of 45 ��A. This dissertation provides a thorough description of the experiment as well as the extracted ratios of inclusive nuclear cross-sections with respect to the deuterium cross-sections (the EMC effect) for the targets ⁹ Be, ¹² C, ¹⁰ B, and ¹¹ B. The …

Chasing Transients: Constructing Local Galaxy Catalogs For Electromagnetic Follow-Up Of Gravitational Wave Events, Chaoran Zhang

Theses and Dissertations

Gravitational waves (GWs) provide a new window for observing the universe which is not possible using traditional electromagnetic (EM) wave astronomy. The coalescence of compact object binaries, such as black holes (BHs) and neutron stars (NSs) generates “loud" GW signals that are detectable by the LIGO-Virgo-KAGRA (LVK) GW Observa- tory. If the binary contains at least one NS, there is a possibility that an observable EM counterpart will be launched during and/or after the merger. The first joint detection of GW radiation (GW170817) and its EM counterpart (AT 2017gfo) greatly extended our understanding of the universe in many fields, such …

Glitch Estimation And Removal Using Adaptive Spline Fitting And Wavelet Shrinkage On The Gravitational Wave Data, Mohammad Abu Thaher Chowdhury

Theses and Dissertations

The false alarm rate and reduced sensitivity of searches for astrophysical signals are caused by transient signals of earthly origin, or "glitches," in gravitational wave strain data from groundbased detectors. The greater number of observable astrophysical signals will increase the likelihood of glitch overlaps and exacerbate their negative impact for future detectors with higher sensitivities. The wide morphological diversity and unpredictable waveforms of glitches, and with the vast majority of cases lacking supplemental data present the main obstacles to their mitigation. Thus, nonparametric glitch mitigation techniques are required, which should operate for a wide range of glitches and, in the …