Physics Commons^™

Tokamak 3d Heat Load Investigations Using An Integrated Simulation Framework, Thomas Looby

Doctoral Dissertations

Reactor class nuclear fusion tokamaks will be inherently complex. Thousands of interconnected systems that span orders of magnitude in physical scale must operate cohesively for the machine to function. Because these reactor class tokamaks are all in an early design stage, it is difficult to quantify exactly how each subsystem will act within the context of the greater systems. Therefore, to predict the engineering parameters necessary to design the machine, simulation frameworks that can model individual systems as well as the interfaced systems are necessary. This dissertation outlines a novel framework developed to couple otherwise disparate computational domains together into …

Towards The Production Of A Self-Consistent Phase Space Distribution, Austin Hoover

Doctoral Dissertations

A self-consistent phase space distribution is a charged particle beam in which the electric field has a linear dependence on the particle coordinates, and in which the linearity of the electric field is conserved as the beam is transported through arbitrary linear focusing fields. These features could increase the possible beam intensity in a circular accelerator by minimizing/eliminating the space charge tune shift/spread. Additionally, the uniform density of known self-consistent distributions would be ideal for fixed-target applications. Finally, certain self-consistent distributions can be flattened by exploiting the relationships between their phases space coordinates and would therefore be useful in a …

The Upgraded Measurement Of The Neutron Lifetime Using The In-Beam Method, Jimmy P. Caylor

Doctoral Dissertations

Precision measurements of neutron beta decay can provide answers to some of the most fundamental questions in particle physics, astrophysics and cosmology. Neutron beta decay is the simplest semi-leptonic decay; therefore, it provides a clean test of the charged current sector of the Standard Model (SM). A precise measurement of the neutron lifetime and λ, the ratio of axial vector and vector coupling constants of the weak interaction, allows for a determination of the Cabibbo-Kobayashi-Moskawa (CKM) matrix element V_ud that is free from nuclear structure effects. The SM predicts that the CKM matrix is unitary; therefore, the measurement of …

Emergent Phenomenon In Jeff=1/2 Iridate, Junyi Yang

Doctoral Dissertations

Recent work on various quantum materials has led to fruitful result including unconventional magnetic states, topological properties, and exotic emergent phenomenon. High T_c superconductivity is one of the prominent properties discovered in quantum materials like strong correlated systems. Though the efforts on understanding this exotic behavior have lasted for years, the mechanism remains elusive owing to the many-body nature of the system and the research scope limitation within cuprates. Recent unravel of J_eff=1/2 state in the iridate square lattice offers alternative to study the complicated many body physics and potentially achieve high T_c superconductivity. In addition, …

Measurement Of Neutrino-Induced Neutron Production In Lead, Brandon J. Becker

Doctoral Dissertations

The COHERENT Collaboration is an experimental effort to make the first measurement of coherent elastic neutrino-nucleus scattering (CE𝜈NS). The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory provides an intense, timed source of neutrinos from the decay of pions and muons produced during the spallation of mercury by 1 GeV protons generated in a particle accelerator. COHERENT seeks to make an unambiguous measurement by using a variety of low-threshold detectors capable of measuring the low-energy nuclear recoils resulting from CE𝜈NS interactions. This already challenging task is further complicated with the presence of backgrounds. Consequently, we must seek to reduce …

Hepatocellular Carcinoma Image-Guided Intervention: Quantitative Characterization Of Reagents For Thermochemical Ablation, Emily A. Thompson

Dissertations & Theses (Open Access)

Thermochemical ablation (TCA) is a minimally invasive therapy under development for hepatocellular carcinoma, a leading cause of cancer death worldwide. TCA utilizes acid-base chemistry delivered simultaneously to induce local ablation when administered. When delivered via a mixing catheter placed directly into the tumor, acid (e.g., AcOH) and base (e.g., NaOH) react to completion at the catheter tip, producing the acetate salt, water, and releasing heat (Δ>50°C) in sufficient quantities to induce lethal osmotic and thermal stress in tumor cells. However, these two reagents are not distinguishable from tissues with noninvasive imaging modalities, which makes monitoring the delivery of TCA …

Automation Of The Transition Identification Procedure For Trapping Rubidium Atoms In A Magneto-Optical Trap, Michael P. Fletcher

Physics

The words “quantum computer” often conjure images of science fiction and unrealistic technology from an impossible future. Some may even believe that they aren’t real or are only theoretical. The truth is that quantum computers are real, tangible systems with real life uses and rooted in credible scientific research. Today, many groups of scientists collaborate on research into better ways of implementing and improving quantum computing techniques. This paper will be addressing the systems required and phenomena used to achieve neutral atom trapping for quantum computation. This thesis will outline the physical phenomena involved with the frequency tuning process for …

Stem Club, Camden Jones, Erica Gesner, Amber Gadeken

Honors Expanded Learning Clubs

The goal of this club is to introduce various topics stemming from different fields in science. We hope to excite the students about science and show them how important it is to their everyday lives. This club also aims to provide free education to underserved communities.

Combining Pharmacokinetics And Vibrational Spectroscopy: Mcr-Als Hard-And-Soft Modelling Of Drug Uptake In Vitro Using Tailored Kinetic Constraints, David Perez-Guaita, Guillermo Quintas, Zeineb Farhane, Roma Tauler, Hugh Byrne

Articles

Raman microspectroscopy is a label-free technique which is very suited for the investigation of pharmacokinetics of cellular uptake, mechanisms of interaction, and efficacies of drugs in vitro. However, the complexity of the spectra makes the identification of spectral patterns associated with the drug and subsequent cellular responses difficult. Indeed, multivariate methods that relate spectral features to the inoculation time do not normally take into account the kinetics involved, and important theoretical information which could assist in the elucidation of the relevant spectral signatures is excluded. Here, we propose the integration of kinetic equations in the modelling of drug uptake and …

Nessie Notation: A New Tool In Sequential Substitution Systems And Graph Theory For Summarizing Concatenations, Colton Davis

Student Research

While doing research looking for ways to categorize causal networks generated by Sequential Substitution Systems, I created a new notation to compactly summarize concatenations of integers or strings of integers, including infinite sequences of these, in the same way that sums, products, and unions of sets can be summarized. Using my method, any sequence of integers or strings of integers with a closed-form iterative pattern can be compactly summarized in just one line of mathematical notation, including graphs generated by Sequential Substitution Systems, many Primitive Pythagorean Triplets, and various Lucas sequences including the Fibonacci sequence and the sequence of square …

Seven Years Of Sn 2014c: A Multiwavelength Synthesis Of An Extraordinary Supernova, B. P. Thomas, J. C. Wheeler, V. V. Dwarkadas, C. Stockdale, J. Vinkó, David Pooley, Y. Xu, G. Zeimann, P. Macqueen

Physics and Astronomy Faculty Research

SN 2014C was originally classified as a Type Ib supernova, but at phase ϕ = 127 days, post-explosion strong Hα emission was observed. SN 2014C has since been observed in radio, infrared, optical and X-ray bands. Here we present new optical spectroscopic and photometric data spanning ϕ = 947–2494 days post-explosion. We address the evolution of the broadened Hα emission line, as well as broad [O iii] emission and other lines. We also conduct a parallel analysis of all publicly available multiwavelength data. From our spectra, we find a nearly constant Hα FWHM velocity width of ∼2000 …

Porous Silicon Photonics For Label-Free Interferometric Biosensing And Flat Optics, Tahmid Hassan Talukdar

All Dissertations

This dissertation uses porous silicon as a material platform to explore novel optical effects in three domains: (i) It studies dispersion engineering in integrated waveguides to achieve high performance group index sensing. With proper design parameters, the sensor waveguides can theoretically achieve 6 times larger group index shift compared to the actual bulk effective refractive index shift. We demonstrate the guided mode confinement factor to be a key parameter in design and implementation of these waveguides. (ii) It explores multicolor laser illumination to experimentally demonstrate perceptually enhanced colorimetric sensing, overcoming the limitations faced by many contemporary colorimetric sensors. Our technique …

Low-Lying Spin-Flip Excitonic States Of ����12��12 (��������)16 [��2��]4 Molecule (Mn12 − ����), Karma Dema

Open Access Theses & Dissertations

Molecules and materials constructed from Mn atoms offer diverse assortments of geomet- rical and spin structures. The diversity of structures, in comparison with other transition metals, along with nature’s decision to use a Mn-based molecule to catalyze solar-driven water splitting and oxygen evolution, suggests that there is indeed something special about the location of Mn valence electrons, both energetically and geometrically, that endows Mn with its multifaceted behaviors that, in turn, provide such chemical, physical and mag- netic diversity. Based upon recent work on the Mn3 monomer and the Mn(taa) there is an expectation that Mn�� �� �� centers can …

Acoustic Waves In The Upper Atmosphere, Geoffrey Blayne Schulthess

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Atmospheric waves can be generated by tropospheric sources such as earthquakes and explosions, causing significant disturbances in the upper atmosphere and ionosphere, where radio wave communications take place. For this analysis, they will be separated into two sub-groups called acoustic waves and gravity waves. Because each of these waves have unique frequency ranges, they can be observed and measured in order to determine their source type and location. Past studies attempted to build the connections between these waves with severe storms and earthquakes, which have improved our understanding of their complexity. Because of the complex nature of these waves, simplified …

Electrothermal Plenum Thruster Simulations Varying Input Pressure And Voltage, Naomi Nicole Ingram

Open Access Theses & Dissertations

A radiofrequency electrothermal thruster is designed and simulated to create a low ionization energy plasma from a neutral propellant using a radio-frequency power. With an asymmetrical surface area ratio between the grounded and powered electrode, ion-neutral charge exchange collisions occurring within the propellant result in propellant heating. The Electrothermal Plenum Thruster conducts this propellant heating in an annular plenum chamber in attempt to maximize propellant heating. A software called CFD-ACE+ is utilized to demonstrate the effects of an enhanced sheath from the asymmetrical power coupling arrangement. Two sets of simulations are run to understand how input variables affect the plasma …

Large-Eddy Simulations Of A Convection Cloud Chamber: Sensitivity To Bin Microphysics And Advection, Fan Yang, Mikhail Ovchinnikov, Subin Thomas, Alexander Khain, Robert Mcgraw, Raymond Shaw, Andrew M. Vogelmann

Michigan Tech Publications

Bin microphysics schemes are useful tools for cloud simulations and are often considered to provide a benchmark for model intercomparison. However, they may experience issues with numerical diffusion, which are not well quantified, and the transport of hydrometeors depends on the choice of advection scheme, which can also change cloud simulation results. Here, an atmospheric large-eddy simulation model is adapted to simulate a statistically steady-state cloud in a convection cloud chamber under well-constrained conditions. Two bin microphysics schemes, a spectral bin method and the method of moments, as well as several advection methods for the transport of the microphysical variables …

Exploring Tunable Magnetization And High-Temperature Ferromagnetism In Ternary Transition Metal-Based Chalcogenides, Hector Iturriaga

Open Access Theses & Dissertations

The discovery of long-range magnetic ordering in ultrathin transition metal-based compounds shows great promise for the development of nanoscale memory and spintronic devices. Composed of cost-effective materials and boasting from strong chemical and thermal stability at low dimensions, van der Waals (vdW) ternary transition metal chalcogenide magnets like CrSiTe3 (CST), Fe2.7GeTe2 (FGT), and Mn3Si2Te6 (MST), provide not only possible energy solutions, but also a broad platform to explore the versatile magnetic character of this family of compounds. Although they have great potential, it has been found that their long-range magnetic ordering exists at temperatures far too low (the highest of …

Control And Calibration Strategies For Quantum Simulation, Paul M. Kairys

Doctoral Dissertations

The modeling and prediction of quantum mechanical phenomena is key to the continued development of chemical, material, and information sciences. However, classical computers are fundamentally limited in their ability to model most quantum effects. An alternative route is through quantum simulation, where a programmable quantum device is used to emulate the phenomena of an otherwise distinct physical system. Unfortunately, there are a number of challenges preventing the widespread application of quantum simulation arising from the imperfect construction and operation of quantum simulators. Mitigating or eliminating deleterious effects is critical for using quantum simulation for scientific discovery. This dissertation develops strategies …

Optimization Of Modular, Long-Range, Ultra-Fast Optical Tweezers With Fluorescence Capabilities For Single-Molecule And Single-Cell Based Biophysical Measurements, Subash C. Godar

All Dissertations

An Optical tweezer is a tightly focused laser beam that applies and senses precise and localized optical force to a dielectric microsphere and offers a unique and effective tool for manipulating the single cell or cell components, including nucleotides and dynein motor proteins. Here, I used highly stabilized optomechanical components and ultra-sensitive detection modules to significantly improve the measurement capabilities over a wide range of temporal and spatial scales. I combined the optical tweezer-based force spectroscopy technique with fluorescence microscopy to develop an integrated high-resolution force-fluorescence system capable of measuring displacements at sub-nanometer, forces at sub-piconewton over a temporal range …

Extractive Membranes For The Detection And Screening Of Waterborne Plutonium, James Foster

All Dissertations

The development of rapid screening tools for special nuclear materials remains a crucial focus for nonproliferation efforts. Traditional approaches for the analysis of trace-level Pu isotopes in water requires tedious and time-consuming sample preparation steps that do not lend well to expeditious screening. Therefore, a novel analytical method that combines both Pu concentration and source preparation into a single detection system would make for an invaluable tool for nuclear security applications. Extractive membranes absorbers can help to fulfill this role as they are capable of concentrating Pu to detectable limits while subsequently serving as alpha spectrometry sample sources. In Chapter …

Experimental Investigations On The Conductance Of Lipid Membranes Under Differential Hydrostatic Pressure, Rose Whiting, Pangaea W. Finn, Andrew Bogard, Fulton Mckinney, Dallin Pankratz, Aviana R. Smith, Elen A. Gardner, Daniel Fologea

Physics Faculty Publications and Presentations

The unassisted transport of inorganic ions through lipid membranes has become increasingly relevant to an expansive range of biological phenomena. Recent simulations indicate a strong influence of a lipid membrane’s curvature on its permeability, which may be part of the overall cell sensitivity to mechanical stimulation. However, most ionic permeability experiments employ a flat, uncurved lipid membrane, which disregards the physiological relevance of curvature on such investigations. To fill this gap in our knowledge, we adapted a traditional experimental system consisting of a planar lipid membrane, which we exposed to a controlled, differential hydrostatic pressure. Our electrophysiology experiments indicate a …

An Afm Approach Applied In A Study Of Α-Crystallin Membrane Association: New Insights Into Lens Hardening And Presbyopia Development, Nawal K. Khadka, Raju Timsina, Laxman Mainali

Physics Faculty Publications and Presentations

The lens of the eye loses elasticity with age, while α-crystallin association with the lens membrane increases with age. It is unclear whether there is any correlation between α-crystallin association with the lens membrane and loss in lens elasticity. This research investigated α-crystallin membrane association using atomic force microscopy (AFM) for the first time to study topographical images and mechanical properties (breakthrough force and membrane area compressibility modulus (K_A), as measures of elasticity) of the membrane. α-Crystallin extracted from the bovine lens cortex was incubated with a supported lipid membrane (SLM) prepared on a flat mica surface. The …

Characteristics Of Mesospheric Temperature And Gravity Waves Over Chile In 2020-2021, Damien M. Devitt, Kenneth Zia

Physics Capstone Projects

Gravity waves (GWs) are often confused with gravitational waves in the fabric of space time. However, there is a clear distinction between them. Gravity wave is a term used by the atmospheric research field to describe perturbations in the atmosphere. Gravity pulls the perturbations down and causes oscillations, these present in the form of waves. The best visualization is to think of ripples on a pond, as the ripple reaches its peak gravity pulls the ripple down and creates an oscillating effect.

Yang-Mills Sources In Biconformal Double Field Theory, Davis W. Muhwezi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

There is a robust and unifying approach to unraveling the roiling mysteries of the universe. Our most compelling accounts of physical reality at present rest on symmetry arguments that are conspicuously geometrical!

105 years ago, Albert Einstein derived gravity from Riemannian geometry. In the general theory of relativity, the world of our experience is a pseudo-Riemannian manifold whose curvature represents the gravitational field. Encoded in the Einstein field equation is how matter sources (energy-momentum tensor) couple to gravity (spacetime curvature). Schematically, the Einstein equation exhibits a more general structure:

Curvature of Spacetime = Material Sources

On one side of the …

Ab Initio Studies Of Structure And Properties Of Group-Iv Monochalcogenide Monolayers, Shiva Prasad Poudel

Graduate Theses and Dissertations

The goal of this dissertation is to study the structure of ferroelectric group-IV monochalcogenide monolayers (MMLs) and their material properties. This work also established a new buckled honeycomb phase of these monolayers. Chapter 1 serves as an introduction where the motivation for these studies is established. In chapter 2, I used eight different exchange-correlation functionals (XC) to study the structure of these 2D ferroelectrics and found that their properties are independent of the choice of XC functionals. These findings reveal that the ground-state ferroelectric unit cell can be described by only five independent parameters, whereas their paraelectric (square or rectangular) …

Prediction Of Pathogenic Mutations In Spermine/Spermidine Synthases, Shannon Bonomi

All Theses

As genetic technology and information become continuously more sophisticated and applied to the prevention and treatment of diseases, the need to understand the effects of genetic variants becomes an important task with regards to assessing disease risk. In the specific case of intellectual disabilities, prenatal screenings is an important diagnostic tool that prepares families and health professionals for the arrival of a child who may need immediate, specialized care. Cell Free DNA screenings are routine for determining sex and provide the opportunity to discover genetic anomalies. However, this has little value unless mutations can be recognized as pathogenic and are …

Ongoing Calculus In The Cerebral Cortex, Luke Long

Physics Undergraduate Honors Theses

Various modes of neuronal computations have long been theorized to be possible based on the structure and geometry of the brain. These computations also seem necessary for many of the integral functions of the brain, like information processing and regulatory processes in the body. However, experimental data directly supporting these claims have been rare.

In this study, data collected in mice from a large number of neurons over a long period of time provided the opportunity to search for some of these computations, specifically change detection and squaring calculations. Using Matlab, the goal of this analysis was to find statistically …

Synthesis, Characterization, And Functionality Of Novel 2d Material Sn3p2, Cory Stephenson

Physics Undergraduate Honors Theses

In recent years, two-dimensional (2D) materials have gained a lot of attention due to their potential applications in devices and their promise to revolutionize technology. In our group, we are capable of synthesizing such materials and study their properties. I have discovered a new material of the tin-phosphorus family that displays the 2D layered structure and therefore shows potential to be used in future devices due to this reduced dimensionality from the typical three-dimensional counterpart. This 2D structure may allow for new phenomena to emerge as there is no longer any interatomic interactions along the z- axis. Under this motivation, …

Scale-Free Behavioral Dynamics Directly Linked With Scale-Free Cortical Dynamics, Sabrina Jones

Physics Undergraduate Honors Theses

In organisms, an interesting phenomenon occurs in both behavior and neuronal activity: organization with fractal, scale-free fluctuations over multiple spatiotemporal orders of magnitude (1,2). In regard to behavior, this sort of complex structure-- which manifests itself from small scale fidgeting to purposeful, full body movements-- may support goals such as foraging (3-6), visual search (4), and decision making (7,8). Likewise, the presence of this sort of structure in the cerebral cortex in the form of spatiotemporal cascades, coined “neuronal avalanches,” may offer optimal information transfer (9). Thus, when considering the functional relationship between the cerebral cortex and movements of the …

Emergent Spectra Of Young X-Ray Emitting Populations Across Environments, Alex Siebenmorgen

Physics Undergraduate Honors Theses

We construct reasonably accurate models of the X-Ray spectra of a multitude of sources in M51. We construct both average and individual models for the sources, which are split into 16 groups as the counts per source increases. Then, we create a plot to show how the model-predicted values of column density (nH) and photon index (gamma) change with luminosity. These models will be used to create an accurate X-Ray stellar energy distribution (SED) for M51, and to better understand how the SED changes with environmental factors like metallicity and star formation rate (SFR).