Digital Commons Network^™

Physical Properties Of Bulk Carbon Nanotube Conductors Impacting Radio Frequency Waveguide Measurements, Samuel J. Boyd

Theses

Recent developments in radio frequency (RF) electronics motivate the interest in developing multi-functional materials which have effective electrical properties with increasing frequency that minimize the conventional skin effect. Carbon nanotubes (CNTs) are emerging as a candidate material due to high direct current (DC) electrical conductivity, flexure tolerance, corrosion resistance, and low density. The DC electrical conductivity of CNT networks is affected by the high resistance junctions between individual or bundled CNTs. Strategies to modify the properties of these junctions have included chemical doping, nano-metal deposition, and physical densification. Alternating current (AC) conductivity measurements of bulk CNT materials to date have …

Binary Neutron Stars: From Interpreting Individual Events To Inferring Population Properties, Anjali Balasaheb Yelikar

Theses

Accurate information from gravitational wave signals from coalescing binary neutron stars provides essential input to downstream interpretations, including inference of the neutron star population and equation of state. However, even adopting the currently most accurate and physically motivated models available for parameter estimation (PE) of binary neutron stars(s), these models remain subject to waveform modeling uncertainty: differences between these models may introduce biases in recovered source properties. In this work, we describe injection studies investigating these systematic differences between the two best waveform models available for BNS currently, NRHybSur3dq8Tidal and TEOBResumS. We demonstrate that for BNS sources observable by current …

Design Of Face-Milled Spiral Bevel Gear Drives With The Desired Conditions Of Meshing And Contact By Application Of The Universal Motion Concept, Akari Tawa

Theses

This thesis aims to improve the computational methodology proposed by Fuentes et al. (2018) for the design of face-milled spiral bevel gear drives in order to get closer to the objective gear tooth surfaces and provide the desired meshing and contact conditions. In the existing computational methodology, all machine-tool settings, excluding velocity ratio, are treated as constants, whereas in this work, the machine-tool settings will be computed by polynomial functions up to the fourth degree of the cradle angle, approach commonly known as Universal Motion Concept (UMC). The proposed approach assumes a predefined geometry for the wheel member of the …

Rural Electrification Subsidies: Quantification, Structure And Policy Implications, Lefu Maqelepo

Theses

This dissertation explores rural electrification subsidies and the policies around them, with an objective of assessing whether there are opportunities to restructure, and therefore redistribute subsidies to a larger portfolio of technology options to accelerate rural electrification and improve energy justice. Redistribution of subsidy necessitates an understanding of the amount of subsidy and how it is distributed. To do this, a quantitative modeling framework that enables for a direct comparison between grid extension and mini grid based electrification pathways based on implicit subsidy required to make connections over a system lifetime was developed and is presented. Using this framework, our …

Impact Of Heat Treatment On Microstructure & Friction Performance Of Nasa Al 398 Alloy Rotors, Manjith Srinivas Koganti

Theses

Interaction of friction brakes with external environment can considerably influence their performance which could relate to friction instabilities and friction induced vibration and noise. The goal of this thesis is to optimize the mechanical properties of Al-alloy and address the friction, wear, and noise heat-treated rotors tested in scaled down SAE recommended testing procedure. The adopted T5 heat treatment process of Al-alloys involves a particular order of controlled heating and cooling steps designed to get specific microstructural changes within the alloy leading to optimized strength/hardness. Hardness is measured with Rockwell’s Hardness Tester. Artificial ageing at elevated temperature process is done. …

On The Computable List Chromatic Number And Computable Coloring Number, Seth Campbell Thomason

Theses

In this paper, we introduce two new variations on the computable chromatic number: the computable list chromatic number and the computable coloring number. We show that, just as with the non-computable versions, the computable chromatic number is always less than or equal to the computable list chromatic number, which is less than or equal to the computable coloring number.We investigate the potential differences between the computable and non-computable chromatic, list chromatic, and coloring numbers on computable graphs. One notable example is a computable graph for which the coloring number is 2, but the computable chromatic number is infinite.

A Mixture-Of-Experts Approach To Fine-Tuning The Segment Anything Model, Rajat Sahay

Theses

The emergence of large, general-purpose foundation models has sparked significant interest in the broader machine learning community. Among the many models being released, the Segment Anything Model (SAM) has demonstrated exceptional capabilities for object segmentation in various settings. Given its expansive training data, SAM has been used for image segmentation across various downstream tasks ranging from tumour segmentation to aerial object detection. However, the majority of pretraining data used by SAM consists of naturally-occurring images, which have significantly different characteristics from images of tumours or images taken by drones. In order to align SAM to these previously unseen domains, we …

Kilonova Modeling And Parameter Inference, Marko Ristic

Theses

This dissertation details the generation of a kilonova simulation training library and the training of subsequent machine learning emulators used for multidimensional interpolation. We begin with a Gaussian process interpolation methodology and apply that emulator for Bayesian inference with the AT 2017gfo light-curve dataset. We then expand on our emulator interpolation methodology, replacing the scalar Gaussian process emulator with a vector neural network emulator for light-curve generation. Our neural network emulator results are localized to a much more narrow region of the parameter space, prompting a detailed supportive investigation of the systematic uncertainty associated with our inference approach. We then …

General Relativistic Magnetohydrodynamics Simulations Of Outflows From Long-Lived Binary Neutron Star Merger Remnants, Allen Wen

Theses

While the landmark multimessenger observations associated with the binary neutron star (BNS) merger GW170817 confirmed the existence of merging BNS systems and their ability to generate gamma-ray bursts and kilonova emission, the exact physical processes that link hydrodynamics in the merger remnant to electromagnetic (EM) signals remains up for debate. Moreover, the uncertain lifetime of the remnant before its possible collapse to a black hole can dramatically change the physics involved in the postmerger evolution. We aim to facilitate and study energetic outflow launching in the long-lived hypermassive or supramassive neutron star remnant case by performing 3D general relativistic magnetohydrodynamics …

The Role Of Food Ordering Systems In The Efficiency Of Food Distribution Through Food Banks: A Case Study, Turner Kamm

Theses

Introduction: Food banks face pressure to support an increasing number of food-insecure individuals, and to increase operational efficiency. This study reviewed the role of ordering systems in a food bank through a literature review and analysis of past ordering data. Methods: A literature review was conducted on the role of food ordering systems on efficient food delivery. Order data were categorized by month, county, and product category to assess transaction patterns. Analyses involved total pounds of food received by each county and a formula to calculate the percent of food insecure individuals served by county. Additional analyses compared items that …

The Logical Reasoning Dilemma Of Llms: A Mapping Deficit In Representation Acquisition, Yiling Wu

Theses

Currently, Large Language Models (LLMs) based on the Generative Pre-trained Transformer architecture have made breakthroughs in multilingual language processing tasks and performed similar language processing capabilities to humans. However, their performance in dealing with tasks involving reasoning, especially logical reasoning, show significant shortcomings. In this paper, we argue that logical reasoning competence requires a certain type of representation acquisition capability. Based on this, in order to assess whether LLMs have the potential to overcome the shortcomings of their logical reasoning competence in their subsequent development, this work compares the representation acquisition processes of humans and LLMs. This comparison reveals that …

Modeling Fire Behavior: Increasing Fidelity In High-Complexity Fire Models, Jenna Sjunneson Mcdanold

Theses

Recent technological advances have yielded several high-complexity models for fire behavior. Low-intensity burns present difficulties in modeling due to a strong sensitivity to wind and fuels. This dissertation explores support research to improve representation of low-intensity fire in these high-complexity fire simulations. We focus on three areas: (i) data-driven modeling with a Spatially Extended Radiant heat Fire model (SERF), (ii) fuel heterogeneity with our model Distribution of Understory using Elliptical Transport (DUET), and (iii) research on whole system dynamics using chaos theory. To increase simulated resolution of low-intensity fire behavior, we employ an observational data set to develop SERF with …

Improvements On Model-Free Sliding Mode Control’S Implementation And Estimation Techniques, Joshua Coleman

Theses

Systems continue to grow in complexity to meet the demands of today’s society. To control severe nonlinearities and protect against errors in the system model, control methods with wider stability margins are necessary. However, most robust control methods require an increased energy cost to guarantee stability with wider margins. Furthermore, most current control methods are derived using system models, which are difficult to develop for complex systems. Model-Free Sliding Mode Control is promising in overcoming the aforementioned difficulties; the control output is only determined by the system order, previous control values, and state measurements. The control scheme’s characteristics have been …

Low Cost Combined Camera And Imu Based Control For Autonomous Aerial Orientation Adjustment, Remi Mckenzie

Theses

The goal of this research was to create a robot control system that combines gyroscope and accelerometer data with vision tracking to improve aerial orientation control performance over what could be achieved with sensor data or image processing alone. There has been significant research into the function of mobile robots that can autonomously carry out a wide range of tasks across a wide range of environments. However, the full potential of these robots has yet to be realized, especially at the hobbyist level. Air based travel allows for motion capabilities far beyond that of a robot limited to ground travel …

Examining Severing Dynamics Of Cytoskeletal Structures Using Computational Methods, Arthur Peterson Miller

Theses

Within eukaryotic cells, cytoskeletal structures are a category of organelles that serve functions ranging from supporting cell geometry to locomotion. These functions require a coordinated effort of regulatory proteins, which interact with the cytoskeleton distinctively. Severing proteins, which can fragment cytoskeletal structures at their binding sites, are one such example. In this work, using stochastic modeling, we model the interaction of severing proteins on bare cytoskeletal filaments and bundled filaments, which are larger collections of individual filaments. We focus on two types of cytoskeletal protein structures in this work: cylindrical microtubules and linear actin filaments. In the case of microtubules, …

An Investigation Of The Sub-Lethal Impacts To Pollinators From Pesticides, Emily Beahm

Theses

In order to feed a growing global population, agricultural practices must utilize pesticides to maintain high yields. Responsible use of pesticides should be based on literature confirming their efficacy and safety. When pesticides are not adequately investigated prior to their release, there can be severe consequences. Many highly effective pesticides, such as the class neonicotinoids, were allowed to be used commercially prior to thorough assessment of their environmental risks, resulting in consequences that largely have fallen to the exposed pollinator populations. To avoid similar outcomes, I tested the popular biopesticide Botanigard which contains Beauveria bassiana, an entomopathogenic fungus previously exposed …

Effects Of Simulated Climate Change On Native Southeastern Grassland Vegetation Using Open Top Chambers, Makaila Carpenter

Theses

The southeastern United States is a critical biodiversity hotspot once covered in prairie grassland ecosystems and now facing significant threats due to urbanization, habitat destruction, over-exploitation, biological invasions, pollution, and climate change. This study analyzes the response of Alabama’s native prairie ecosystem to climate change. We used open top chambers (OTCs) to simulate climate change-induced warming. We assessed the response of ecosystem function and structure to higher temperatures (1-3^oC). The indicators of ecosystem function included phenology, leaf surface area (LSA), specific leaf area (SLA), and aboveground and below net primary productivity (ANPP and BNPP respectively). Ecosystem structure was …

Ap Art History For Marshall Public Schools, Gage Bunting

Theses

Advanced Placement Art History (AP Art History) is a course that, while being one of the less popular AP offerings, exists in thousands of schools already. College Board is the institution that facilitates these courses and sets the requirements each school must follow in order to offer the course. With that said, there is not a rigid requirement that all courses be taught in the same manner, and because of that, the curriculum of this project was adapted to enhance learning for students of Marshall High School.

The art department of Marshall High School has evolved in recent years and …

Music Education In The Urban Classroom: Issues Of Equity And Access, Lakeisha Walker

Theses

Music education in urban classrooms plays a crucial role in shaping students' overall development and academic success. The field of music education is not immune to the challenges of equity and access that exist in urban settings. It is essential to address these issues to ensure that all students have equal opportunities to participate in music programs and reap the countless benefits that come with them.

The importance of this topic in the field of music education cannot be overstated. Research has shown that students who participate in music programs demonstrate improved academic performance, enhanced cognitive skills, and increased creativity. …

Gustav Klimt: A Modern Representation Of The Pregnant Female Body, Emma Fanger

Theses

This thesis analyzes Gustav Klimt’s Hope I (1903) and Hope II (1907–1908) to explore how the artist offered a revolutionary and rare representation of pregnancy at the turn of the twentieth century. Klimt, a key figure in the Symbolist and Art Nouveau movements, is recognized for his decorative, allegorical, and emotionally charged style. His portrayal of the pregnant female body challenged traditional artistic conventions. This thesis argues that Hope I and Hope II are significant not only for their modern visual language, but also for their contribution to the limited representation of pregnancy in Western art. In addition to examining …

A Spectroscopic Search For Recoiling Supermassive Black Holes In Nearby Active Galaxies, Emily Temple

Theses

It is hypothesized that following a galaxy merger the two central supermassive black holes (SMBH) become a binary system, eventually coalescing due to emission of gravitational waves. This coalescence results in a single black hole, with an accretion disk shining with high luminosity that photoionizes the surrounding gas. Therefore, the newly merged SMBH is visible as an active galactic nucleus (AGN). However, the gravitational waves are emitted anisotropically by the binary as it inspirals, resulting in a recoil kick. This ejects the newly merged SMBH from the AGN’s center of the galaxy. The SMBH oscillates around the galaxy’s center of …

Impacts Of Professional Development On Researchers, Kayleigh M. Patterson

Theses

In this work, I study the effectiveness of Professional development for Emerging Education Researchers (PEER) using a framework adapted from one that evaluates professional development for teachers. Professional Development (PD) is the process of learning information after one’s main school for job settings. These cover job/career specific skills that are not taught during schooling, since they are normally more specific. While a Ph.D. does set up a lot of specific skills, due to a changing research climate based on discoveries and organizational standards, there are always more skills to learn for a researcher. Therefore, there are professional development for researchers …

Geo-Slam: Using Geometric Hierarchies To Support Localization And Mapping In Forest Environments, Daniel Castellarin

Theses

Robust mapping and localization can be challenging in environments like forests where easily observable landmarks are virtually indistinguishable from each other. In such environments, GPS or robot odometry may also be compromised by the landscape, tree cover, or method of locomotion. Prior work discussed a method for creating geometric hierarchies to describe the relative positions of unlabeled landmarks. Notably, the polygons from these hierarchies were used to perform accurate place recognition from observations containing partial overlap and sensor noise. Here, we use geometric hierarchies to perform robust data association for collections of virtually identical 2D landmarks in direct support of …

The Effect Of Angiogenesis On Thermal Properties Of In-Vivo Human Tissue, Shriya Musuku

Theses

Bioheat transfer is the study of heat transfer in biology. There are several sources of heat in biology including external ones such as surgical applications of heat, or internal ones like cancer tissue. Blood flow networks affect both types of processes and are often generated during disease phenomenon through a process called angiogenesis. This affects the properties of the tissue. Several attempts were made to model flow and heat transfer within various tissues through physical measurements or computer simulations. Both types of models used bioheat transfer models do not consider the geometry of vasculature at its most fundamental level. The …

Bert-Boosted Adaptive Learning, Dibyanshu Chatterjee

Theses

Knowledge Tracing is a machine learning technique that aids in monitoring a learner’s knowledge in a given learning environment. This thesis introduces a unified approach to adaptive learning, specifically with the use of Knowledge Tracing (KT) and other relevant machine learning models, that can aid in creating a personalized learning environment for a learner on an Intelligent Tutoring System (ITS). While contemporary ITS exemplars, such as Knewton and Adaptemy, strive to provide seamless adaptive learning experience, most such ITS platforms do so by employing individualized models, each tai- lored to distinct tasks, for example, some models may predict correctness of …

Using Machine Learning Algorithms To Predict Outcomes Of Chess Games Using Player Data, Sofia Decredico

Theses

Chess is a two-player game, popular with a wide variety of people, ranging from people who play casually every once in a while with their family to professional players who make their living through playing and teaching. There are three outcomes that a chess game could have: player 1 (White) wins, player 2 (Black) wins, or both players draw. Using an online database called “The Week In Chess” which contains information about 2.5 million chess games, a variety of machine learning methods are tested to predict the outcomes of chess games. The features investigated as inputs for classification are: White’s …

Multimodal Data Fusion And Model Compression Methods For Computer Vision, Manish Sharma

Theses

This dissertation explores the advanced integration of deep learning (DL) techniques in remote sensing (RS) and computer vision (CV), with a focus on optimizing convolutional neural networks (CNNs) for enhanced detection performance and efficient computational deployment. The first part of the research addresses the underperformance of conventional object detection methods when applied to RS data. Traditional techniques often struggle due to the small size of targets, limited training data, and diverse modalities involved. To overcome these challenges, we introduce YOLOrs, a novel CNN designed specifically for real-time object detection within multimodal RS imagery. YOLOrs is adept at detecting objects across …

Securing The Inbox: Advancing Phishing Email Detection With Fine-Tuned Bert, Fatima Rashed Al Saedi

Theses

In recent years, phishing attacks have persisted as a widespread threat in the contemporary digital environment, presenting substantial risks to individuals and organizations. Cybercriminals are devising increasingly sophisticated strategies to deceive users through malicious emails. In response to this challenge, this research focuses on developing a new tool for detecting phishing emails utilizing the BERT algorithm. The tool aims to enhance email security by accurately identifying deceptive emails and protecting users from potential cyber threats. The primary objective of this study is to investigate how leveraging the BERT algorithm can improve the detection of phishing emails compared to traditional methods. …

Optimization Methods For Parameter Estimation In A Scalar Partial Differential Equation: Stochastic Variants, Yidan Yang

Theses

In this work, we present stochastic variants of an optimization method for the problem of recovering a spatially varying parameter in a scalar partial differential equation (PDE) from measurement(s) of the state variable. In many inverse problems associated with PDE models, the goal is to utilize observational measurements of the state variable in the estimation of the model parameter(s). In the problem being studied, the hydraulic conductivity of an aquifer (a function of location) is the parameter/coefficient to be recovered and the hydraulic (or piezometric) head is the quantity observed/measured. We discuss the choices of objective functional (such as output …

Models Of Rrna Templated Assembly Of The Nucleolus In The C. Elegans Embryo, Nishant Kodan

Theses

The nucleolus is a large membraneless organelle located in the nucleus of eukaryotic cells. It is a multicomponent structure primarily made of RNA and proteins and serves as the site of ribosome biogenesis. It has been extensively studied as a prototype of a membraneless organelle whose assembly is driven by phase separation, but factors affecting the dynamics of nucleolar assembly are not well understood. Experiments show that the size of the nucleolus scales with the size of the nucleus, which decreases through reductive divisions in the early C. elegans embryo. These observations are consistent with the idea that a finite …