Physical Sciences and Mathematics Commons^™

The Relationship Between Urban Heat Islands And Redline Districts, Emily Cornwell

Undergraduate Theses and Capstone Projects

As climate change worsens and the world attempts to find solutions to global changes, it is important to identify how climate change will affect individual communities. Climate resilience tactics aim to protect vulnerable populations against environmental harms, such as excess heat. Historically, communities of color face forms of environmental racism. One example of structural racism includes the loans given out by the Home Owners Loan Corporation during the 1940s which “redlined” certain communities of color by refusing to give these neighborhoods loans and rated these areas undesirable for loaners. Urban heat islands occur in residential, densely populated areas with lots …

Effects Of Precipitation On Groundwater Level In An Urban Watershed, Andrew Golladay

Undergraduate Theses and Capstone Projects

Groundwater is an important aspect of a watershed, as it is a reservoir for the storage of water. It both releases water to the surface in dry periods and absorbs excess water in wet periods. Precipitation provides surface water that is then absorbed to replenish groundwater. The specific purpose of this research was to determine the recharge rate of the water table after a rainfall event, with a goal to also develop a framework or long-term monitoring of the water table along an urban stream in Lynchburg, Virginia, and to establish baseline groundwater data before a dam is removed from …

Dementia Classification Through Textual Analysis With Machine Learning Algorithms, Joseph Hurowitz

Undergraduate Theses and Capstone Projects

The goal of this work is to build a classifier that can identify whether a patient is suffering from Alzheimer’s Disease of the Dementia Type (AD). A corpus of 2751 texts was used from the DementiaBank database, where each conversation is transcribed and marked using the CHAT format. Each text was analyzed by frequency of disfluencies, use of aphasic language, and lexical features. All parsed data was used to train a Random Forest, Naïve Bayes, and Support Vector Machine algorithm. These classification algorithms will be tested on the combination of all features, as well as each set of features individually.

The Behaviors Of Bert Attention Heads In Stereotype Detection, Joseph H. Hajjar

Dartmouth College Master’s Theses

We are living in the age of information, where it has become increasingly easy to share ideas, news, and content which are seen by an increasingly large number of people. This increasing scope of the increasing amount of data that is being shared lends itself to the question: how can we determine whether what we are reading promotes a stereotype? Previous work has applied transformer based models in this domain yielding impressive performance, but few studies exist interpreting the nature of attention heads in this task. Our work explores the feature encoding and extraction behaviors of attention heads in transformer …

Correlation Functions Of The Anharmonic Oscillator: Numerical Verification Of Two-Loop Corrections To The Large-Order Behavior, Ludovico T. Giorgini, Ulrich D. Jentschura, Enrico M. Malatesta, Giorgio Parisi, Tommaso Rizzo, Jean Zinn-Justin

Physics Faculty Research & Creative Works

Recently, the large-order behavior of correlation functions of the O(N)-anharmonic oscillator has been analyzed by us [L. T. Giorgini et al., Phys. Rev. D 101, 125001 (2020)PRVDAQ2470-001010.1103/PhysRevD.101.125001]. Two-loop corrections about the instanton configurations were obtained for the partition function, the two-point and four-point functions, and the derivative of the two-point function at zero momentum transfer. Here, we attempt to verify the obtained analytic results against numerical calculations of higher-order coefficients for the O(1), O(2), and O(3) oscillators, and we demonstrate the drastic improvement of the agreement of the large-order asymptotic estimates and perturbation theory upon the inclusion of the two-loop …

Hodge Theoretic Compactification Of Period Maps, Haohua Deng

Arts & Sciences Graduate Student Theses and Dissertations

In this article, we review some aspects regarding Hodge-theoretic completion and boundarybehavior of period maps. First, we recall some classical results on compactification of classical period domains e.g. Baily-Borel, Ash-Mumford-Rapoport-Thai. The works produced by Kato-Usui aims at generalizing Mumford’s toroidal compactification to nonclassical period domain, which depends on construction of a strongly compatible fan. We prove such a fan can not exists universally, but for a single geometric variation of Hodge structure. We proceed such a construction on a 2-parameter geometric variation coming from Hosono-Takagi’s family of Calabi-Yau threefolds of type (1, 2, 2, 1). Moreover, we briefly review the …

Some Problems In Reproducing Kernel Spaces, Christopher Felder

Arts & Sciences Graduate Student Theses and Dissertations

The two chapters of this thesis are comprised of work in the setting of reproducing kernel (Hilbert) spaces. These are Banach (or Hilbert) spaces of functions defined on some set, with the special property that point evaluation, on the underlying set, is bounded. The first chapter deals with the study of inner functions. These functions have a rich history in function and operator theory in the Hardy spaces of the unit disk. The first section of this chapter studies the relationship between generalized inner functions and optimal polynomial approximants. The second section, which is joint work with Trieu Le, deals …

The Evaluation Of Radiometal Labeled Biomolecules For Imaging And Therapeutic Applications, Truc Huynh

Arts & Sciences Graduate Student Theses and Dissertations

Radiometals play a crucial role in nuclear medicine for the diagnosis and therapy of various diseases including cancer and neurological disorders. In fact, there is a broad range of radiometals that are currently in use for imaging and therapy such as 99mTc, 89Zr, 68Ga, 177Lu, and 64/67Cu. Radiometal use in nuclear medicine has been stimulated by advances in radionuclide production that allow for fast, reliable, and cost-efficient production and an extensive understanding of molecular targets and tumor biomarkers. In recent years, there has been a growing interest in theranostics - the combination of imaging and therapy related to the same …

Properties Of Cyclic Functions, Jeet Sampat

Arts & Sciences Graduate Student Theses and Dissertations

For $1 \leq p < \infty$, consider the Hardy space $H^p(\mathbb{D}^n)$ on the unit polydisk. Beurling's theorem characterizes all shift cyclic functions in the Hardy spaces when $n = 1$. Such a theorem is not known to exist in most other analytic function spaces, even in the one variable case. Therefore, it becomes natural to ask what properties these functions satisfy in order to understand them better. The goal of this thesis is to showcase some important properties of cyclic functions in two different settings. 1. Fix $1 \leq p,q < \infty$ and $m, n \in \mathbb{N}$. Let $T : H^p(\mathbb{D}^n) \xrightarrow{} H^q(\mathbb{D}^m)$ be a bounded linear operator. Then $T$ preserves cyclic functions, i.e. $Tf$ is cyclic whenever $f$ is, if and only if $T$ is a weighted composition operator. 2. Let $\mathcal{H}$ be a normalized complete Nevanlinna-Pick space, and let $f, g \in \mathcal{H}$ be such that $fg \in \mathcal{H}$. Then $f$ and $g$ are multiplier cyclic if and only if their product $fg$ is. We also extend $(1)$ to a large class of analytic function spaces that includes the Dirichlet space, and the Drury-Arveson space on the unit ball $\mathbb{B}_n$ among others. Both of these properties generalize all previously known results of this type.

Quantum Curves And Asymptotic Hodge Theory, Soumya Sinha Babu

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation explores a 2015 conjecture of Codesido-Grassi-Marino in topologicalstring theory that relates the enumerative invariants of toric CY 3-folds to the spectra of operators attached to their mirror curves. In the maximally supersymmetric case, our first theorem relates zeroes of the higher normal function associated to an integral K2-class on the mirror curve to the spectra of the operators for curves of genus one, and suggests a new link between analysis and arithmetic geometry. On the other hand in the ’t Hooft limit, [KM, MZ] deduced from the [CGM] conjecture that the limiting values of the local mirror map …

Classical And Quantum Markov Chains Derived From Billiard-Like Systems, Joshua Covey

Arts & Sciences Graduate Student Theses and Dissertations

Random billiards are a class of random dynamical systems related to dynamical billiards. We extend the study of random billiards and their associated Markov chains in two new directions. First, we introduce a new class of billiard-like systems called lensed billiards, which introduce a step potential to the usual billiard set-up, and conduct an exploratory study of random lensed billiards where we are mainly interested in how the newly-introduced potential parameter relates to the spectral gap and set of moments of the Markov operator associated to the random lensed system. Second, we recast the mathematical set-up of random billiards to …

Distributed X-Ray Sources For X-Ray Imaging And Small Animal Flash Irradiator, Yuewen Tan

Arts & Sciences Graduate Student Theses and Dissertations

Emerging distributed x-ray source technology enables new designs for x-ray imaging systems. The multi-pixel thermionic emission X-ray (MPTEX) source, a distributed x-ray source developed in our lab, was assembled and tested. With a multi-row CdTe photon-counting detector, forty-eight x-ray fan beams of MPTEX source were able to cover a 25-cm cross-sectional and 8-cm axial field of view. Tetrahedron-beam x-ray imaging techniques using MPTEX source were demonstrated.Ultra-high dose rate radiotherapy or FLASH radiotherapy (RT) potentially can reduce normal tissue toxicity in radiation treatments. A compact irradiator that can deliver FLASH-RT treatments similar to conventional RT treatments is needed for preclinical studies. …

A Nonconforming Finite Element Method For The 2d Vector Laplacian, Mary Barker

Arts & Sciences Graduate Student Theses and Dissertations

The vector Laplacian presents difficulties in finite element ap- proximation. It is well known that for nonconvex domains, H1- conforming approximation spaces form a closed subspace of the solution space H(div; Ω) ∩ H(curl; Ω). Hence H1-conforming approximations will fail to converge. This is problematic as it is highly difficult to construct more general finite dimensional ap- proximation spaces for this space. We will present an extension of a nonconforming method introduced by Brenner et al. The method was originally given for P1-nonconforming spaces in two dimensions. Our extension is given for degree r polynomials, but which agrees with the …

Electronic, Optical, And Thermal Probes Of The Layered Mott Insulator Α-Rucl3 In The Atomically Thin Limit, Jesse Balgley

Arts & Sciences Graduate Student Theses and Dissertations

Alpha-ruthenium(III) chloride (α-RuCl3) is a layered Mott insulator and van der Waals material that can be cleaved down to a single atomic layer. This material is a promising candidate to realize the Kitaev quantum spin liquid, a strongly correlated phase of matter expected to host fractionalized quasiparticles and a potential platform for topological quantum computation. When α-RuCl3 is placed in direct contact with the layered semimetal graphene we observe a strong charge transfer between the two materials despite the electrically insulating nature of α-RuCl3, which absorbs ≈ 4 × 10^13 electrons/cm^2 from the graphene. Remarkably, this charge transfer persists and …

Weighted Estimates For The Bergman And Szegö Projections, Nathan Andrew Wagner

Arts & Sciences Graduate Student Theses and Dissertations

This thesis is a study of various weighted estimates for the Bergman and Szegö projections on domains in several complex variables. The starting point of our analysis is a bounded, pseudoconvex domain D ⊂ Cn. The Bergman and Szegö projections are both orthogonal projections onto spaces of holomorphic functions associated with D. While it is immediate that both of these operators are bounded on L2, it has been a topic of substantial interest to determine their mapping properties on Lp, where the boundary geometry of D plays amajor role. Given a linear operator T acting on measurable functions that is …

Signaling Studies Of Protein-Peptide Binding On Microelectrode Arrays, Kendra White

Arts & Sciences Graduate Student Theses and Dissertations

Electrochemical methods provide unique opportunities for non-traditional synthesis and analytical studies. Using electrochemistry, we are able to synthesize individually addressable molecular surfaces on microelectrode arrays and then utilize the surface to probe interactions between receptors and their biological targets. To date, cyclic voltammetry signals can be used to detect biological interactions between proteins and small molecules on the surface of an array, however those signals are often amplified by the presence of a large number of small molecules by any given electrode. This amplification makes it difficult to obtain binding data using the arrays that can be compared with existing …

Low-Temperature Plasticity Of Rock-Forming Minerals, Michael Keith Sly

Arts & Sciences Graduate Student Theses and Dissertations

The rheology of the Earth’s crust and mantle is in part governed by the physical and mechanical properties of feldspar, quartz, calcite, and olivine. Over the past several decades a significant number of experimental studies have been performed on these minerals. Conventional experiments are generally performed at elevated temperatures because much of the viscoplastic deformation of these minerals is accommodated by high-temperature mechanisms. There is, however, evidence of viscoplastic deformation at lower temperatures (T ≤ 0.3Tm) in the uppermost mantle and throughout the crust. Micromechanical experimental techniques, including nanoindentation and micropillar deformation, can be used to achieve plastic deformation at …

Contribution To Data Science: Time Series, Uncertainty Quantification And Applications, Dhrubajyoti Ghosh

Arts & Sciences Graduate Student Theses and Dissertations

Time series analysis is an essential tool in modern world statistical analysis, with a myriad of real data problems having temporal components that need to be studied to gain a better understanding of the temporal dependence structure in the data. For example, in the stock market, it is of significant importance to identify the ups and downs of the stock prices, for which time series analysis is crucial. Most of the existing literature on time series deals with linear time series, or with Gaussianity assumption. However, there are multiple instances where the time series shows nonlinear trends, or when the …

Exploring The Solar System Through Space And Time Via Laboratory Investigations Of Extraterrestrial Material, Kainen Lee Utt

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation reports the results of laboratory studies of lunar soil samples, gas-to-solid filamentary enstatite grains from a likely-cometary interplanetary dust particle (IDP), and exogenous clasts in the CH3 chondrite Acfer 182 that likely originated from a differentiated basaltic planetesimal. These studies were performed using multi-instrument analyses involving high-resolution scanning and transmission electron microscopy (SEM/TEM) techniques, nanoscale secondary ion mass spectrometry (NanoSIMS), synchrotron infrared nanospectroscopy (SINS), electron probe microanalysis (EPMA), and Raman spectroscopy. The results of these analyses are used to examine space weathering phenomena, energetic processing and radial transport in the protoplanetary disk, and the origins of igneous inclusions …

Artificial Intelligence, Controls, And Sensor Fusion For Optimization And Modeling Of Space Missions And Particle Accelerators, Reza Pirayeshshirazinezhad

Mechanical Engineering ETDs

This PhD dissertation is devoted to developing artificial intelligence (AI) applications for space missions and particle accelerators considering constraints on the computational resources. The space mission studied in this research, the Virtual Telescope for X-ray Observations (VTXO), is the mission exploiting 2 6U-CubeSats operating in a precision formation. The goal of the VTXO project is to develop a space-based, X-ray imaging telescope with high angular resolution precision. VTXO space mission is designed and the mission is optimized to increase the performance of the mission. Trajectory optimization with AI, hybrid control, control algorithms, and high performance computing are all used to …

Mapping The Impact Of A Trailway System On The Amount Of Trash Present Within Two, Lillian Smith

Undergraduate Theses and Capstone Projects

Transportation of debris within water systems is a prominent occurrence which has been linked to natural and artificial processes including wind, rain, and littering. This pilot study established methods to determine if a trail system is a good implementation to achieve recreation and connectivity goals laid out in the City of Lynchburg’s Tyreeanna & Pleasant Valley Neighborhood Plan. Blackwater Creek watershed, which contains an established trail system, and Fishing Creek watershed, containing a non-established trail system, were the two locations where this study’s methods were conducted. Use of the Virginia GIS Open Access Portal was essential in delineating the boundary …

Evolution Of Eigenvalues Of A Geometric Operator Under Ricci Flow On A Riemannian Manifold, Paul Bracken

School of Mathematical & Statistical Sciences Faculty Publications

The behavior of the eigenvalues of a geometric operator closely related to the Laplacian under Ricci flow is investigated. These depend on a coupling parameter in the operator as well as an evolution parameter which gives a flow on a compact manifold of finite dimension. The main objective is to study the monotonicity properties of the eigenvalues.

Statistical Analyses Of Hemp Cannabinoid Test Results, Rachel J. Stegmeier

Senior Honors Projects, 2020-current

Cannabis sativa L. is a flowering plant used for recreational and industrial purposes that produces a class of compounds called cannabinoids. Industrial hemp is a strain of Cannabis sativa L. that has been propagated to have a low Δ 9 tetrahydrocannabinol (Δ⁹THC) and a high cannabidiol (CBD) content. With recent advancements in legislation, farms are now growing hemp for fiber, CBD production and other hemp derived product purposes but crops risk being destroyed if THC content levels exceed the current maximum legal limit of 0.3%. For the present study hemp samples were dried, ground, extracted with various alcohols, …

The Effect Of Surface Gas/Liquid Entrapment On Drag Reduction, Haosen Tan

Mechanical Engineering Research Theses and Dissertations

Economic globalization has made today’s world more closely linked, where transportation (e.g. shipping, pipeline) has played an important role. Approximately over 60% (in air), 80% (underwater), and 100% (in pipeline) propulsive power is used to overcome surface drag, so reducing surface drag will have a substantial impact economically and environmentally.

To develop a surface that has lower drag, the intuitive idea is to convert no-slip boundary conditions to slip or partial slip ones. To achieve that, the most promising approach is to replace the solid-liquid boundaries completely or partially with gas-liquid or liquid-liquid boundaries, because the shear stress is much …

Steps Toward The Total Synthesis Of The Chrysosporazine Family, Katie Kaczynski

Electronic Theses and Dissertations

Cancer is one of the leading causes of death worldwide, with 19.3 million new cancer cases and 10 million deaths in 2020 alone. In the United States, cancer was the second leading cause of death after heart disease. One of the reasons that cancer is so frequently terminal is that cancerous cells frequently develop multidrug resistance (MDR) to frontline chemotherapeutical treatments, resulting in cancers cannot be treated and are inevitably fatal. This makes the discovery of ways to combat MDR so important in the treatment of cancer. The chrysosporazines are a family of recently discovered (2019) natural products that have …

Human Trafficking And Machine Learning: A Data Pipeline From Law Agencies To Research Groups, Nathaniel Hites

Computer Science and Engineering Theses and Dissertations

Human trafficking is a form of modern-day slavery that, while highly illegal, is more dangerous with the advancements of modern technology (such as the Internet), which allows such a practice to spread more easily and quickly all over the world. While the number of victims of human trafficking is large (according to non-profit organization Safe House, there are estimated to be about 20.5 million human trafficking victims, worldwide (“Human Trafficking Statistics & Facts.” Safe Horizon)- co-erced or manipulated by traffickers into either forced labor, or sexual exploitation and encounters), the number of heard cases is proportionally low- several thousand successful …

Real Time Call-Flagging System To Respond To Suicidal Ideation In Call Centers, Vishnu Menon, Joseph Carrigan, Charles Floeder, Thomas Walton, Devin Mcguire

Honors Program: Senior Projects (Public)

The 2021-2022 Signature Performance Design Studio team developed a live audio call-flagging system that enables faster responses and new response pathways to veteran crises by call service representatives and their management team. Using a custom made deep learning model, live audio streaming server, and Teams broadcasting add-on, the system empowers Signature Performance call service representatives to make quicker and more well informed decisions to provide veteran’s the best care possible.

Soymeal Based Bio-Based Adhesive For Wood Application, Prashant Kote

Electronic Theses & Dissertations

Introducing bio-based materials as an alternative to petroleum-based products has been the greatest challenge for the industry which may reduce environmental problems. Currently, most of the wood adhesive is prepared using formaldehyde which is a non-renewable source as well as toxic. In this research, soybean meal was used as a renewable bio-based source for wood adhesive which has a potential to replace formaldehyde-based adhesives. In this study, soymeal was chemically modified, characterized, and evaluated for its adhesion performance, flow behavior, service life, and thermal stability.

In the first, soymeal was modified using acid (HCl), alkali (NaOH), and salt (CaCl_{2 …}

Nutrient Restoration Of A Large, Impounded, Ultra-Oligotrophic Western River To Recover Declining Native Fishes, Ryan S. Hardy, Tyler J. Ross, Kevin N. Mcdonnell, Michael C. Quist, Charlie Holderman, Bryan S. Stevens

United States Geological Survey: Staff Publications

Declines in many fish populations in large, western rivers have been primarily attributed to the anthropogenic reduction of nutrient inputs and subsequent impacts to the food web. The largest known river fertilization program was implemented starting in 2005 on the Kootenai River in northern Idaho to restore resident fisheries. Annual electrofishing surveys were conducted at multiple sites in Idaho and Montana before and during nutrient addition to evaluate assemblage and population-level responses. Although few responses in fish assemblage structure were observed, the addition of liquid ammonium polyphosphate fertilizer (3 μg/L) to the Kootenai River increased fish abundance and biomass over …

One-Step Synthesis Of Corn Oil-Based Polyol For Highly Flame-Retardant Rigid Polyurethane Foams, Tenzin Ingsel

Electronic Theses & Dissertations

Rigid polyurethane foams (RPUF), heavily utilized in construction, refrigeration, and the automotive industries, are a significant class of polyurethanes. They can substantially enhance energy efficiency by improving thermal insulation. However, the application of petrochemical sources in polyurethane has raised environmental concerns.

Such concerns call for the development and application of new bio-based polyurethanes to potentially reduce humanity's over-reliance on nonrenewable sources.

In this work, corn oil-based polyol was synthesized via popularized thiol-ene reaction. The obtained polyol was characterized by wet chemistry methods, spectroscopic evaluations, and chromatography. Non-halogenated flame retardants of cost-effective and environmentally friendly nature were incorporated into the polyurethane …