Physical Sciences and Mathematics Commons^™

Survival Patterns Among Adult And Pediatric Bone Cancer Patients, Ethan Estes

Mathematical Sciences Undergraduate Honors Theses

Recently noted, Huang et al. (2023), machine learning (ML) models, while offering great advantages over traditional statistical predictive modeling methods, are less explored in the analysis of survival and other similar time-to-event predictive data modeling. ML methods such as neural networks offer a great deal of promise but need to be further explored to investigate their comparative power in predicting survival outcomes. Focusing specifically on survival analysis in adult and pediatric bone cancer patients, traditional methods, like shown in Emmert-Streib and Dehmer (2019), will be shown with machine learning models using methods in Hothorn, Hornik, and Zeileis (2006). In this …

Geospatial Science And The Changing Environment: Applied Methods For Sustainable Agriculture And Landscape Management, Harrison Wakefield Smith

Graduate Theses and Dissertations

Rapid environmental change is disrupting agricultural productivity, ecological function, and the long-term resilience of managed landscapes. At the same time, the rapid growth of geospatial data science has improved our understanding of environmental change and increasingly is being used to improve sustainability in agricultural and environmental management. However, critical gaps remain that limit the applicability of data-driven insights in landscape management. This dissertation investigates the potential of geospatial analytics for sustainable agriculture and landscape management, with a focus on applied methods that operate across spatial and temporal scales. Using field, landscape, regional, and national datasets, it explores the capabilities and …

Can Methanogens Grow On Asteroids?, Isabella N. Reimer

Biological Sciences Undergraduate Honors Theses

Because of asteroids’ chemical features, they may serve as potential environments for life and are of interest in astrobiology. Dr. Kral’s laboratory studies methanogens, microorganisms in the domain Archaea, as possible life forms on extraterrestrial bodies. Since some methanogens can withstand harsh environmental conditions and produce methane as a waste product, methane production can be used as an indicator of potential microbial activity.  In this study, three methanogen species, Methanothermobacter wolfeii, Methanobacterium formicicum, and Methanosarcina barkeri were tested for growth on asteroid simulants based on the Orgueil (CIE-1) and Murchison (CME-1) meteorites. First, methanogen growth was assessed in the …

The Environment, Health, And Vector Nexus: Evaluating The Spatiotemporal Variability And Societal Impact Of Ticks In Arkansas, Dalton Williams

Graduate Theses and Dissertations

Tick-borne diseases (TBDs) are a surging public health and veterinary concern in the United States. In states like Arkansas, climate change and shifting land use have recalibrated the ecological niches of vector species. This research utilizes species distribution and ecological niche modeling to assess the spatiotemporal suitability of ixodid tick habitats, specifically where environmental and socioeconomic factors intersect. By integrating spatial science with public health frameworks, this study identifies priority intervention areas in underserved rural regions where healthcare resources are often constrained. This study provides a comprehensive methodological framework, leveraging remote sensing datasets and historic disease data to delineate exposure …

Augmented Reality In Fashion Retail: A Walmart Unlimited Study, Chloe A. Mcpherson

Apparel Merchandising and Product Development Undergraduate Honors Theses

As technology continues to evolve, augmented reality (AR) has become increasingly common within the retail and fashion industries. This study explored Gen Z consumers’ perceptions of immersive AR shopping experiences through Walmart Unlimited, an interactive digital shopping platform. The purpose of this research was to better understand how younger consumers respond to AR-enhanced shopping environments and whether these technologies influence attitudes toward convenience, engagement, and sustainability in retail.

A quantitative research design was used for this study. Participants completed the Walmart Unlimited shopping experience and then responded to a Qualtrics survey measuring areas such as immersion, satisfaction, ease of use, …

Advancement In Electrochemical Generation-Collection: Snapshot Redox Cycling Voltammetry For Rapid Analysis At Chip-Based, Individually Addressable Microband Electrode Arrays, Blake Aleck Sterling

Graduate Theses and Dissertations

Snapshot redox cycling voltammetry (Snapshot RCV) is introduced as a rapid electrochemical technique that reconstructs the current-potential profile of a redox active species using a microband electrode array. By simultaneously biasing individual generator electrodes alternating in the array to different voltages across the analyte’s potential range while individually holding collector electrodes at a reversing potential, “spatial” voltammetry is achieved in as little as 1 s with the temporal speed of chronoamperometry, rapidly capturing the steady-state redox cycling (RC) profiles. During RC (a mode of generation-collection), the analyte is oxidized (or reduced) at generator electrodes and converted back at neighboring collector …

Explainability In Deep Learning For Density Regression, Dalton James Oxford

Graduate Theses and Dissertations

Classical statistical methods focus on explainability and inferential power. Machine learning and deep learning can handle non-linear, high-dimensional data better than traditional methods. In modeling, a clear understanding and interpretation are essential to decision-making. Recent work in quantile regression and extreme modeling has begun to use deep learning due to its performance on high-dimensional, non-linear data. Semi-Parametric Quantile Regression (SPQR) is a nonparametric spline-based approach to quantile regression that estimates the conditional PDF and CDF of the response. Semi-Parametric Quantile Regression for Extremes (SPQRx) is a recent extension of SPQR that provides two features: out-of-sample estimation and accurate extreme-tailed estimation. …

Strain Engineering Of Excitonic And Vibrational Properties In Two-Dimensional Transition Metal Dichalcogenides, Sneha Minesh Patel

Graduate Theses and Dissertations

Mechanical strain represents a robust and non-invasive method for tuning the electronic and vibrational properties of two-dimensional transition-metal dichalcogenides (TMDs). This work examines homogeneous biaxial strain as a symmetry-preserving control parameter that governs excitonic and interlayer dynamics in atomically thin TMDs. In monolayer MoSe2, biaxial tensile strain is intrinsically generated during high-temperature physical vapor deposition due to thermal expansion mismatch with amorphous substrates. Optical spectroscopy demonstrates substantial and tunable excitonic energy shifts exceeding 100 meV per percent strain. Polarization-resolved second harmonic generation confirms the retention of lattice symmetry under biaxial deformation. The investigation is further extended to bilayer MoS2, where …

F.L.A.I.R. -- A Flow-Level Autoencoder For Intrusion Recognition, Joseph P. Dumond

Electrical Engineering and Computer Science Undergraduate Honors Theses

Industrial Internet of Things (IIoT) networks underpin critical infrastructure worldwide, yet securing them remains an open challenge. Traditional intrusion detection systems require labeled attack data for training, a resource that is rarely available in real industrial deployments. They also fail against novel threats, a model trained on known attacks has no basis for detecting anything outside its training set. This thesis presents a Flow-Level Autoencoder for Intrusion Recognition, or FLAIR, a fully unsupervised deep learning system for network intrusion detection in IIoT environments. FLAIR is built on a Gated Recurrent Unit (GRU) autoencoder trained exclusively on normal network traffic. Rather …

From Mobilenet To Repvit: A Survey Of Edge-Optimized Computer Vision Architectures, Eli A. Bosch

Electrical Engineering and Computer Science Undergraduate Honors Theses

Edge-optimized computer vision is a constantly evolving field where the definition of efficiency has changed repeatedly. This thesis presents a literature survey of four recent Convolutional Neural Network (CNN) families, all analyzed through a consistent framework of accuracy, parameter count, and Multiply-Accumulate Operations (MACs), alongside a survey of five CNN and Vision Transformer (ViT) hybrid models to examine the direction of the field. It was found that accuracy follows a logarithmic curve with respect to parameter count, exhibiting diminishing returns as models scale. This suggests that architectural design contributes more to performance gains than parameter count alone. Theoretical efficiency metrics …

A Case Study On Using Large Language Models To Drive Convergence-Oriented Literature Discovery In Critical Infrastructure Security, Caden J. Williamson

Electrical Engineering and Computer Science Undergraduate Honors Theses

In the world of cybersecurity, the rapid development of artificial intelligence proposes a constant challenge for researchers to defend critical infrastructure. Attacks on critical infrastructure can be catastrophic, and emerging strategies of cyber-adversaries that implement leading AI models can expose vulnerabilities in critical infrastructure much faster than previous tools. To defend against this emerging threat, the Cybersecurity Research Working Group at the University of Arkansas is aiming to develop a cross-domain and cross-discipline center of excellence. To support this effort, the group is writing a literature review on the topics of AI and critical systems security. Literature review is an …

Phase Equilibria Modeling Constraints On Seismic Velocity And Density For Mafic Granulites In The Athabasca Granulite Terrane, Western Canadian Shield, Olivia Wyllie

Geosciences Undergraduate Honors Theses

Samples of mafic granulite and eclogite from the Athabasca granulite terrane, thought to be representative of the lower continental crust, were analyzed via bulk geochemistry analysis and seismically modelled with Perple_X v.7.1.6. Modeled P-wave speeds, S-wave speeds, and densities for the samples were graphed by region and calculated for wet (1.00 wt.% H2O) versus dry (0.01 wt.% H2O) conditions at 460 °C and 648 °C. The samples were found to have higher median P-wave values than those determined by Rudnick and Fountain (1995; 7.4 km/s to 7.8 km/s, as compared to 6.9 km/s to 7.2 km/s). This indicates both a …

Isolation, Purification, And Characterization Of Α-Galactosidase From Watermelon (Citrullus Lanatus), Christopher Henley Jr.

Chemistry & Biochemistry Undergraduate Honors Theses

The enzyme α-galactosidase is a type of glycosidase that removes galactose sugar units from larger molecules in cells. Compounds that inhibit glycosidases have been useful for understanding the structure and function of the enzymes they inhibit, and some have been used to treat certain diseases. Using inhibitors of α-galactosidase to study its characteristics and mechanisms may provide insights into its role in disease and its general utility. Advances in fields such as agriculture, sustainable fuels, and biomedicine may be facilitated by inhibition studies of α-galactosidase, but the current library of known inhibitors is relatively lacking. Obtaining α-galactosidase enzymes from chemical …

Tunable Physical Color In Nanostructured Materials: Exploring Reversible Mechanisms For Active Optical Control, Matt Hughes

Chemistry & Biochemistry Undergraduate Honors Theses

Vanadium Dioxide (VO₂) thin films have been grown on silicon wafers using atomic layer deposition of TDMAV (tetrakis(dimethylamino)vanadium(IV)) and H₂O as precursors. A quartz crystal microbalance (QCM) measurement was used during deposition to confirm growth and resulted in a growth rate of approximately 0.6 Angstroms/cycle. X-Ray Reflectivity (XRR) was performed to confirm growth thickness and reported an approximately 30 nm thin film after 500 cycles of TDMAV precursor deposition. X-Ray photoelectron spectroscopy was utilized to determine the phase of the vanadium samples and confirmed the presence of vanadium dioxide as prepared and after annealing under nitrogen …

Hollow Nickel-Iron Nanoshells As Electrocatalysts For The Oxygen Evolution Reaction, Jonathan Batey

Chemistry & Biochemistry Undergraduate Honors Theses

The development of highly active and affordable catalysts for the oxygen evolution reaction is crucial to achieve a future where hydrogen is generated cleanly using renewable methods. Ni-Fe nanocatalysts show great promise in this area, as they are affordable and highly active. However, to overcome the industrial dominance of steam methane reforming, their activity needs improvement. This work aims to increase the activity of Ni-Fe nanocatalysts by making hollow nanostructures. Hollow Ni-Fe nanostructures were synthesized by coating a Cu template with Ni and Fe, followed by the etching of the Cu template. This left hollow Ni-Fe nanoshells, which were used …

Impaired Tunability Of Brain State And Motor Dysfunction In A Mouse Model Of Rett Syndrome, Victoria Kindler Norman

Graduate Theses and Dissertations

Rett syndrome (RTT) is a rare neurological disorder, caused by disrupted function of the MECP2 gene, resulting in impaired cognitive and motor functions. Previous studies suggest that although MECP2 has important functions throughout the body, the etiological origins of RTT-related dysfunction should be sought within the brain. However, it remains a mystery how neural population dynamics are altered in the RTT brain and how these alterations relate to motor dysfunction. Previous studies using an RTT mouse model point to abnormal correlations among firing rates of neurons. Here we hypothesize that such disrupted neural activity correlation could be caused by abnormal …

Collective Dissipative Charging And Energy Extraction In Quantum Batteries, Sagar Pokhrel

Graduate Theses and Dissertations

In this dissertation, we investigate the charging and discharging dynamics of a quantum battery composed of a collectively driven ensemble of $N$ identical two level systems coupled to a structured electromagnetic environment. The system is described using collective angular momentum operators in the Dicke basis, which provides a compact and physically transparent framework for analyzing collective light-matter interactions. Rather than treating dissipation as an unwanted source of loss, we explicitly use it as a mechanism for energy storage and work extraction. Starting from a coherently driven ensemble coupled to common reservoirs, we derive a master equation in Lindblad form under …

Fret Studies On The Binding Of Fibroblast Growth Factor (Fgf) Proteins To The Hard Corona Of Cuins2-Based Quantum Dots, Colette Robinson

Graduate Theses and Dissertations

Fibroblast Growth Factor (FGF) has been shown to be an important protein in angiogenesis, which is critical in developmental biology and wound healing but has also been implicated in cancer metastasis. FGF interacts with an FGF Receptor (FGFR) to signal the onset of angiogenesis but the detailed mechanism of angiogenesis, and particularly its regulation, is still largely unknown. Imaging the interaction of FGF with FGFR in biologically-relevant environments, such as directly in cells, is key towards furthering this understanding and may eventually aid in the development of better cancer treatments. CuInS2/ZnS quantum dots (QDs) are an attractive fluorescent probe to …

Age And Characteristics Of Quaternary Fluvial And Dune Deposits Along The Arkansas And Cimarron Rivers In Osage And Pawnee Counties, Oklahoma, Barry A. Duncan

Graduate Theses and Dissertations

Quaternary aeolian and fluvial deposits along the Arkansas and Cimarron Rivers in Osage and Pawnee counties of central Oklahoma, record Late Pleistocene and Holocene fluvial landscape history in the eastern Osage Plains. Sediment supply, climate variability, channel incision, and channel migration control this landscape evolution. Sediment supply of both streams is dominantly sand. Late Pleistocene and Holocene precipitation have varied with periods of drought alternating with increased precipitation and warming. The study area is near the eastern boundary of substantial aeolian activity with drought and aeolian reworking of fluvial sand more severe to the west. This study examines the sediment, …

Geothermal Gradient And Lithium Co-Generation Power Potential In Lafayette County, Arkansas, Juan Agustin Falquez

Graduate Theses and Dissertations

The Smackover formation in south Arkansas is a known reservoir for brines with high temperature and salinity. Recently, Smackover formation brines in Lafayette County, Arkansas are a target for lithium extraction. A county-wide dataset of Bottomhole Temperatures (BHT) is used to estimate a lower bound geothermal gradient of 36 C/km and a reservoir temperature of 116 C at an approximate depth of 2725 m. The high temperatures make the brines a candidate for geothermal power co-generation. Geothermal power co-generation can be achieved by implementing an Organic Rankine Cycle (ORC) power plant. The Southwest Arkansas Lithium project anticipates a total of …

Advancing Apparel Education Through 3d Simulation In Vstitcher: Confidence, Competence, And Career Readiness In Higher Education, Jonah Diniakos Graham

Graduate Theses and Dissertations

The rapid adoption of 3D garment simulation in the apparel industry has created new demands of higher education to better prepare students with both technical proficiency and confidence within digital design platforms to better enable them for many career avenues. This study examines the integration of Browzwear’s VStitcher in an undergraduate apparel production course, addressing the need to assess both competence and self-confidence in digital garment construction while also fostering broader career readiness competencies. Guided by a combination of Self-Determination Theory (SDT) and Situated Expectancy-Value Theory (SEVT), the study emphasizes the role of autonomy, competence, and relatedness in the shaping …

Geospatial Analysis Of The Influence Of Wastewater Disposal On The Induced Seismicity In Oklahoma, Usa, Kristine Nagy

Graduate Theses and Dissertations

Seismic records over the past decade and a half have indicated a significant increase of earthquakes in the state of Oklahoma and the evidence has strongly suggested the rise is likely caused by substantial wastewater disposal operations, a subsequent process of oil and natural gas extraction. This study investigated the relationship between wastewater disposal via injection wells, and its influence on inducing earthquakes in Oklahoma by employing Geographic Information System (GIS) tools for geospatial data integration and spatial analysis using United States Geological Survey (USGS) earthquake data and Underground Injection Control (UIC) Class II well data sourced from the Oklahoma …

Deciphering Chemomechanical Couplings In Proteins Using Molecular Dynamics And Enhanced Sampling Techniques, Matthew Brownd

Graduate Theses and Dissertations

Proteins function through a complex interplay between chemical interactions and mechanical motions across multiple spatial and temporal scales. Understanding how ligand binding, conformational dynamics, and structural flexibility collectively regulate protein function remains one of the central challenges in molecular biophysics. This dissertation presents a computational investigation into chemomechanical coupling in three distinct classes of biomolecular systems using all-atom molecular dynamics (MD) simulations and enhanced sampling methods, with particular emphasis on free-energy calculations and long-timescale conformational analysis. The first part of this work focuses on ligand binding in hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which regulate rhythmic electrical activity in the heart …

Groundwater Responses To Tidal Restoration At Pelican Marsh And Sea-Level Rise In Elkhorn Slough, California, Julie E. Nelson

Graduate Theses and Dissertations

Coastal wetlands represent a dynamic but vulnerable terrestrial-aquatic interface with future resilience controlled by historic hydrologic alterations, sea-level rise, and groundwater extraction. In diked coastal settings, poor tidal connectivity can degrade habitat from the impoundment of freshwater or hypersaline surface waters. Restoring tidal connectivity could foster marsh revitalization, but altering the surface hydrologic system could lead to unwanted salinity intrusion in shallow aquifers. Saline groundwater intrusion degrades freshwater quality and, while inevitable with sea-level rise, could be accelerated with tidal marsh restoration. To investigate this, I developed a steady-state groundwater flow model of Pelican Marsh, a diked, muted tidal marsh …

Grazed Pasture Effects On Greenhouse Gas Emissions In The Ozark Highlands, Tyler Buchanan

Graduate Theses and Dissertations

In the United States (US), grazinglands serve as the main foundation for the livestock industry, and, in Arkansas specifically, pastures are essential for rotational grazing and dairy operations. Climate change is increasingly becoming a concern in the agriculture industry, largely caused by anthropogenic activities increasing greenhouse gas (GHG) concentrations in the atmosphere, at least partly due to the nutrient recycling that occurs from animal manure additions in grazinglands. Therefore, quantifying GHG emissions from pastures is essential to better understanding the impacts of grazing on the environment. The objective of this study was to quantify and evaluate the potential effects of …

Sedimentary Provenance Of The Pliocene – Pleistocene Giant Foresets Formation, Offshore Taranaki Basin, Aotearoa New Zealand, Anurag Kulkarrni

Graduate Theses and Dissertations

Sediment input and dispersal in the Taranaki Basin, offshore New Zealand’s North Island, was influenced by a complex interplay of ocean currents and sea level fluctuations over the late Neogene. This period of time was recorded in the Pliocene-Pleistocene Giant Foresets Formation (GFF) that represents a rapid progradation of the western continental shelf into the basin. High sedimentation rates during this time were likely a major contributing factor to the emplacement of multiple, large-scale (up to ~3,500 km3) mass-transport deposits (MTD) that were caused by shelf and slope collapse within the GFF of similar scale to that of the well-studied …

Do I Have To Know Someone? The Impact Of Factors Beyond The Playing Field That Affect Mlb Hall Of Fame Voting., Jackson Wollscheid

Economics Undergraduate Honors Theses

With the creation of WAR (Wins above Replacement), it has created an index to measure the player’s value using a variety of statistics relevant to that player’s position. The higher a player’s career WAR then the greater the impact that player had on the game during his career. However, players are not simply inducted into the Hall of Fame on this measure of value but on voting from members of the BBWAA (Baseball Writers’ Association of America). This research investigates external factors outside of standard playing statistics’ influence on Hall of Fame voting, including team affiliation, career length, and other …

Nanoscale Electrochemical Measurements: Theory, Instrumentation, And Operation, Kamsy Lerae Anderson

Graduate Theses and Dissertations

Electrochemical processes underpin many modern technologies (e.g., batteries, fuel cells, and corrosion protection systems), and because these processes are often controlled by interactions that occur at the nanoscale, gaining insight into nanoscale electrochemical behavior is essential to advancing these technologies. Nanoscale electrochemical imaging probes measure electrochemical activity with nanoscale spatial resolution and have enabled researchers to gain new insights into diverse experimental systems. However, limitations remain, including a lack of methods for direct quantitative interpretation, the influence of atmospheric conditions on experimental reproducibility and stability, and a knowledge barrier resulting from limited accessible resources, all of which continue to restrict …

Of Dunes And Ice: A Surface-Atmosphere Investigation Of Mars Co2 Sublimation Features And Titan Aeolian Fields, Racine D. Cleveland

Graduate Theses and Dissertations

This dissertation investigates a central question: How do planetary boundary layer processes manifest in observable surface geomorphology, and how can planetary imagery be used to quantify those effects? The planetary boundary layer (PBL) governs near-surface exchanges of momentum, heat, and volatiles, yet direct atmospheric measurements remain spatially and temporally limited on most planetary bodies. By analyzing geomorphic features preserved in high-resolution imagery, this work quantifies how boundary-layer processes leave measurable signatures on planetary surfaces. For Mars, high-resolution images from the Mars Reconnaissance Orbiter (MRO) HiRISE instrument were used to map CO2 sublimation features, or Swiss Cheese Features (SCFs), on the …

Conservation Agriculture Effects On Greenhouse Gas Emissions From Cotton, Soybean, And Corn In Southeast Arkansas, Jonathan Benjamin Brye

Graduate Theses and Dissertations

The slow degradation of natural resources has resulted in the focus of agriculture shifting towards conservation practices, such as reduced/no-tillage, cover crops (CC), and organic amendments (i.e., biochar), that conserve and improve natural resource quality. The objectives of this thesis were to i) quantify the impacts of biochar rate (i.e., 0, 2000, and 4000 kg ha-1) and ii) the combination of CC and tillage practice on carbon dioxide (CO¬2), methane (CH4), and nitrous oxide (N2O) fluxes, growing-season-long emissions, global warming potential (GWP), soil properties, and plant response from a minimally tilled cotton (Gossypium hirsutum)-corn (Zea mays) rotation and a soybean …