Digital Commons Network^™

Analysis Of Dynamic And Final Surface Subsidence Movements Over Subcritical Panels In The Eastern Us, Mauricio Parra Valencia Sr

Theses and Dissertations--Mining Engineering

Subsidence prediction is a critical field in mining engineering, focusing on anticipating ground movements caused by underground coal extraction. Accurately forecasting these movements is essential for protecting surface structures and infrastructure from damage. However, despite extensive research by mining professionals worldwide, reliable prediction remains challenging, especially in complex environments like subcritical mining areas and locations characterized by highly variable topography. These conditions introduce non-linear rock mechanics that often complicate the application of traditional predictive models. This thesis utilizes measured subsidence data related to the extraction of two adjacent longwall panels in a deep coal mine in the eastern US to …

Analysis Of Ptfe Radial Lip Seals For Wheel Bearing Applications, Madison Vogt

Theses and Dissertations--Mechanical and Aerospace Engineering

A numerical analysis was conducted to investigate the viscoelastic effects of nonlinear materials on the sealing zone and contact pressure distribution of radial lip seals in a conventional geometric topology. The use of nonlinear materials in radial lip seal applications is desirable to improve operation and reliability of rotating machinery due to their high operating temperatures, chemical compatibility, and low friction coefficients. Examples include, but are not limited to, seals within industrial air compressors, turbine engines, aircraft landing systems, chemical processing equipment, and Freon pumps. This work focuses on analyzing the nonlinear viscoelastic response of pure Polytetrafluoroethylene (PTFE) and PTFE …

Analysis Of Closed-Loop Dynamical Systems Using Relu Nns, Pouya Samanipour

Theses and Dissertations--Mechanical and Aerospace Engineering

This thesis develops a framework for analyzing the stability and invariance properties of closed-loop dynamical systems whose dynamics are derived from neural networks with rectified linear units (ReLUs). The ReLU neural network defines continuous piecewise affine (PWA) functions, which makes them ideal for analysis using polyhedral geometry and optimization techniques. To begin, we introduce two exact algorithms for enumerating polytopic regions of affine behavior induced by ReLU networks: a half-space-based method that checks the feasibility of activation patterns and a geometric vertex-based method. Using these methods, we are able to perform precise region-wise analysis, and these methods serve as the …

Machining-Induced Residual Stress Modeling Using Physics-Informed Neural Networks, Md Mehedi Hasan

Theses and Dissertations--Mechanical and Aerospace Engineering

Process-induced residual stress (RS) plays a critical role in determining the structural integrity, fatigue life, corrosion resistance, and dimensional stability of manufactured components. Tensile residual stress can be harmful to the machined workpiece by lowering fatigue strength, while compressive residual stress helps to prevent such issues. Therefore, accurate prediction and control of machining-induced residual stresses are essential for optimizing manufacturing processes and enhancing component performance. However, existing modeling approaches—empirical, analytical, and numerical—often have limited predictive accuracy, demand extensive calibration, or involve high computational costs. Traditional finite element analysis (FEA) provides modeling insights but is constrained by its high computational cost …

Development Of An Immersed Boundary Method-Wall Modeled Large Eddy Simulation Approach For Incompressible Flows And Aeroacoustic Predictions, John C. Higgins

Theses and Dissertations--Mechanical and Aerospace Engineering

The performance capabilities of rotorcraft have improved significantly in the past decade as both manned and unmanned rotorcraft become a larger part of future transportation systems. Private companies as well as various government offices have worked to develop capabilities ranging from transportation/package delivery to intelligence/surveillance to livestock monitoring. Their practicality in both rural and urban areas, however, is questionable due to the significant tonal and broadband noise which is produced by the rotors. Public acceptance of rotorcraft, namely small Unmanned Aerial Vehicles (sUAVs), in transportation systems is an issue largely associated with the noise generation and it's effect on nearby …

Direct Numerical Simulation Of Pulsating Flow In Curved Pipes: Insights Into Aortic Dissection In Humans, Gokul Anugrah Gopakumar

Theses and Dissertations--Mechanical and Aerospace Engineering

This dissertation investigates the hemodynamics of pulsating blood flow in curved vessels through direct numerical simulations (DNS), with the overarching aim of uncovering fluid dynamic mechanisms linked to the onset and progression of aortic dissection in humans. The work is structured in two parts: (i) fundamental studies in idealized geometries and (ii) preliminary investigations in patient-specific anatomies. In the first part, curved pipe models representing the aortic arch are used to isolate the effects of pulsation frequency, amplitude ratio, and curvature ratio on transitional and turbulent flow dynamics. The simulations reveal that curvature-driven centrifugal forces shift the peak velocity toward …

High-Altitude Balloon-Launched Uncrewed Aircraft System Measurements Of Atmospheric Turbulence And Qualitative Comparison With Infrasound Microphone Response, Anisa Haghighi

Theses and Dissertations--Mechanical and Aerospace Engineering

This study explores the use of a balloon-launched uncrewed aircraft system (UAS) to measure atmospheric turbulence in the troposphere and lower stratosphere using both wind velocity measurements and infrasonic acoustic energy. The UAS, a glider configured for autonomous descent along a predefined trajectory, had on board, in situ sensors to capture thermodynamic and kinematic atmospheric parameters. Additionally, it carried an infrasonic microphone to evaluate its potential for remotely detecting clear-air turbulence by capturing infrasonic waves. The system’s performance was assessed over the course of three test flights conducted in New Mexico, USA, in 2021. The descent enabled high-resolution profiling, with …

Simulation-To-Hardware Validation Of Mpc For Binary Thruster 2d Cubesat Control, Aevar Amundinusarson Oefjoerd

Theses and Dissertations--Mechanical and Aerospace Engineering

Small satellites must execute precise, fuel-limited maneuvers under strict actuation and operational constraints. Model Predictive Control (MPC) is a suitable approach because it optimizes future actions while explicitly enforcing these limits. This work evaluates (1) whether MPC can operate in real time using binary (on/off), asymmetric thrusters, and (2) whether a high-fidelity digital twin can be used to tune and validate the controller prior to hardware testing.

An MPC framework was implemented on a planar satellite prototype that floats on air bearings, operates at 16.7 Hz (60 ms period), and uses eight binary thrusters exhibiting up to 13.2% variation in …

Enhancing Public Health Surveillance: Development And Validation Of Machine Learning Models For Suspected Opioid Overdose Detection In Emergency Medical Services Data, Peter J. Rock

Theses and Dissertations--Clinical and Translational Science

The ongoing opioid overdose crisis in the United States requires timely and accurate surveillance systems to inform public health responses. Traditional public health surveillance methods rely on hospital discharge data and death certificates, which suffer from significant reporting delays and miss cases where patients refuse hospital transportation. Emergency Medical Services (EMS) data presents a promising alternative with advantages in timeliness and case ascertainment but lacks validated definitions for suspected opioid overdose (SOO).

This dissertation addresses this critical gap through the development, validation, and fairness assessment of machine learning models with natural language processing (ML-NLP) for identifying SOOs in EMS data. …

Diagnosing Statistical Education Needs Of Health Science Learners, Amy S. Nowacki, Ann M. Brearley, Robert A. Oster, Emily Slade, Katrina L. Devick, Matthew J. Hayat, Sally W. Thurston

Biostatistics Faculty Publications

Many types of health science learners, including clinical and translational scientists, students, researchers, and clinicians, seek to increase their knowledge of biostatistics. These learners are heterogeneous in their field, career stage and career focus. Based on the collective experience of an expert panel with over 115 years teaching statistics to health science learners, we propose a framework for considering the needs of health science learners motivated by their career goals. This framework defines four types of health science learners seeking statistical training: (a) consumers, (b) “milestone makers”, (c) biomedical researchers with statistical support, and (d) biomedical researchers without statistical support. …

Soil Phosphorus Retention In A Palustrine Wetland Chronosequence Of The Northern Mississippi Embayment, Cora Lee Aossey

Theses and Dissertations--Plant and Soil Sciences

The USDA NRCS Agricultural Conservation Easement Program Wetland Reserve Easements is focused on converting marginal agricultural lands to wetlands to restore hydrologic function and enhance wetland habitat. There is a gap in knowledge of how phosphorus (P) dynamics develop as these wetlands are converted from row crops to wetland vegetation over time. Recently converted wetlands have the potential to develop into P sinks. In this study, a chronosequence of former farmlands converted to forested palustrine wetlands in the northern Mississippi Embayment was used to evaluate the potential mobility of P post-conversion. Three soil depth intervals were analyzed for water-soluble P, …

S6k1 Is A Targetable Vulnerability In Tumors Exhibiting Plasticity And Therapy Resistance, Saptadwipa Ganguly, Ravshan Burikhanov, Vitaliy M. Sviripa, Sally Ellingson, Jieyun Jiang, Christian M. Gosser, David Orren, Eva M. Goellner, Gautham G. Shenoy, Mahadev Rao, John D’Orazio, Christine F. Brainson, Chang Guo Zhan, Peter H. Spielmann, David S. Watt, Vivek M. Rangnekar

Physiology Faculty Publications

Background: Most tumors initially respond to treatment, yet refractory clones subsequently develop owing to resistance mechanisms associated with cancer cell plasticity and heterogeneity. Methods: We used a chemical biology approach to identify protein targets in cancer cells exhibiting diverse driver mutations and representing models of tumor lineage plasticity and therapy resistance. An unbiased screen of a drug library was performed against cancer cells followed by synthesis of chemical analogs of the most effective drug. The cancer subtype target range of the leading drug was determined by PRISM analysis of over 900 cancer cell lines at the Broad Institute, MA. RNA-sequencing …

Characterization Of Municipal Solid Waste Using Machine Learning Based Imaging And Chemical Analysis, Enyonam Ahadzi

Theses and Dissertations--Biosystems and Agricultural Engineering

According to the U.S. Department of Energy’s 2023-billion-ton report, the United States generates nearly 300 million tons of municipal solid waste every year. More than 50% of that waste is underutilized and ends up in landfills. This poses serious public health and environmental risks. But beyond the environmental and health implications, this is also a wasted opportunity. The U.S. Energy Information Administration estimates that, for every 100 lbs of waste we throw away, about 85% can be used as fuel or for electricity generation. However, its complex and heterogeneous nature poses challenges for efficient sorting and valorization in waste to …

Valorizing Municipal Solid Waste For Sustainable Aviation Fuel And Polyhydroxyalkanoate Bioplastics: Pyrolysis And Microbial Pathways, Emon Das

Theses and Dissertations--Biosystems and Agricultural Engineering

The escalating global burden of municipal solid waste (MSW), projected to reach 3.88 billion tons annually by 2050, calls for innovative valorization strategies to mitigate environmental impacts and promote a circular bioeconomy. This thesis investigates the conversion of MSW into two high-value products: sustainable aviation fuel (SAF) and polyhydroxyalkanoate (PHA) bioplastics. Chapter one presents comprehensive physicochemical characterization and pyrolysis-GC/MS analysis of MSW feedstocks. The physicochemical results reveal that densification enhances handling and storage properties, while pyrolysis-GC/MS analysis indicates that plastic-rich MSW streams produce bio-oils with favorable hydrocarbon profiles suitable for SAF production, potentially contributing to decarbonization efforts in the aviation …

An Exploration Of Ibdp Coordinator Leadership In Southeastern U.S. Public High Schools, Raymond W. Scheetz Jr.

Theses and Dissertations--Educational Leadership Studies

Along with its brand, vision, and curricula, International Baccalaureate (IB) provides member schools with requirements and expectations, such as implementing a program coordinator. However, the need for flexibility that would allow for global implementation leaves the nature of IB’s required program coordinator positions subject to local discretion in many ways. However, while increasing in numbers globally, IB Diploma Programs are still not widely implemented in public high schools throughout the U.S. Southeast. As a result, the position of an IBDP coordinator is unusual in such schools in the region. Also, the IBDP coordinator position has not been substantially defined or …

How Elementary Schools Support Families In Mandatory Middle School Choice: A Comparative Case Study, Eleni Filippatos

Theses and Dissertations--Educational Leadership Studies

This dissertation examines the role of New York City elementary school leaders in shaping fifth graders' middle school choice processes in two public schools serving predominantly economically disadvantaged, Latino families. As school choice increasingly influences students' academic trajectories, understanding how leaders engage families in this decision-making process is essential for promoting educational equity. The study explored how public elementary school principals, counselors, and teachers support families during the universal middle school application process.

Using a qualitative comparative case study design, I conducted semi-structured interviews, field observations, and document analysis to compare leadership practices at two demographically similar elementary schools with …

Empowering Future Educators: Exploring Preservice Elementary Teachers’ Self-Efficacy Within Integrated Stem Experiences In A Science Methods Course, Shane C. Campbell

Theses and Dissertations--Education Sciences

There is an ongoing need for preparing high-quality preservice elementary teachers who are confident and capable in the design and delivery of integrated STEM instruction. This qualitative study examines the experiences of a small cohort of preservice elementary teachers enrolled in a science teaching methods course and further examines how preservice teachers' perceptions of self-efficacy change as a result of their participation in integrated STEM experiences in science methods coursework. Data were collected using pre and post surveys to capture self-reported efficacy levels related to STEM teaching, along with semi-structured interviews conducted before and after the course to further contextualize …

Tiered Coalition Formation Game Variants, Stability, And Simulation, Nathan Arnold

Theses and Dissertations--Computer Science

Tiered coalition formation games (TCFGs) have been proposed for modeling the ordering of power in intransitive structures. Furthering our understanding of the usefulness of this concept requires a close examination of this game and its variants, as well as the delineation between stability concepts and methods of finding stable outcomes. Derived from a simulation of the performance of characters in the games Pokémon Red and Blue Versions, we present an approximation of its power structure found via machine learning. We compare our findings to the community consensus ranking presented on a fan-run website, and further comment on the stability of …

Temporal Team Formation Games With Dynamic Preferences, Cameron Egbert

Theses and Dissertations--Computer Science

In the professional world, it is imperative for management entities to allocate their human resources to a work schedule, and such models of coalition formation games are well-studied. However, most existing literature only considers coalition formation in the context of a single moment in time, without accounting for changing preferences among individuals as they work together. The primary contribution of this thesis is a new team formation game that incorporates skill-based team formation and a dynamic variant of Additively Separable Hedonic Games. These Temporal Team Formation Games with Dynamic Preferences (TTFG-DPs) allow for two psychologically common preference dynamics: a preference …

Development Of Software For Genetic Distances, Genotyping, And Phylogenetics Using Rna-Seq Data, Andrew C. Tapia

Theses and Dissertations--Computer Science

This dissertation concerns a new application of RNA-seq data—computation of pairwise genetic distance matrices. RNA-seq captures sequences of RNA molecules in some cells or tissues of interest. RNA-seq provides data are well-suited to studies examining gene expression, and its use for this purpose is currently widespread. A pairwise genetic distance matrix, the main topic of this dissertation, quantifies differences in the genomes of every pair of samples (e.g., individuals) in a given set. Genetic distance matrices are versatile; they can be used for various kinds of downstream analyses, including genotyping, phylogenetics, and genetic diversity measurement. Although DNA sequence data are …

Information-Theoretic Methods For Efficient Training And Robust Evaluations In Self-Supervised Learning, Oscar Skean

Theses and Dissertations--Computer Science

Self-supervised learning (SSL) has become a cornerstone of modern machine learning, offering a scalable alternative to costly human annotation by constructing pretext tasks directly from raw data. While SSL has delivered strong results across vision, language, and multimodal domains, two major limitations persist: (1) SSL methods are often significantly slower to train than supervised counterparts, and (2) evaluation protocols remain narrow, with most studies relying on linear probing accuracy on the pretraining dataset. . These challenges are particularly acute for large language models (LLMs), where training costs and interpretability of intermediate representations are critical concerns.

In this work, we propose …

A Multi-Objective Optimization Model For Cropland Design Considering Profit, Biodiversity, And Ecosystem Services, Caleb H. Geissler, Nathan L. Haan, Bruno Basso, Ames Fowler, Douglas A. Landis, Tyler J. Lark, Christos T. Maravelias

Entomology Faculty Publications

More sustainable agricultural methods are needed to alleviate the decreases in biodiversity and ecosystem services that have occurred because of industrial agriculture. One such method is the inclusion of alternative crops into croplands that can support biodiversity, reduce erosion and chemical runoff, and sequester carbon in the soil. However, the question of where such crops should be planted to balance competing economic and environmental objectives remains open. To this end, we develop a mixed-integer quadratically constrained program to optimize the layout of a cropland considering economic, biodiversity, greenhouse gas emissions, and water quality objectives. We include spatially varying fertilization as …

Establishing Performance Criteria For Evaluating Watershed-Scale Sediment And Nutrient Models At Fine Temporal Scales, Aayush Pandit, Sarah Hogan, David Tyler Mahoney, William I. Ford, James F. Fox, Christopher Wellen, Admin Husic

Civil Engineering Faculty Publications

Watershed water quality models are mathematical tools used to simulate processes related to water, sediment, and nutrients. These models provide a framework that can be used to inform decision-making and the allocation of resources for watershed management. Therefore, it is critical to answer the question “when is a model good enough?” Established performance evaluation criteria, or thresholds for what is considered a ‘good’ model, provide common benchmarks against which model performance can be compared. Since the publication of prior meta-analyses on this topic, developments in the last decade necessitate further investigation, such as the advancement in high performance computing, the …

Exploring The Collective Efficacy Of Elementary Special Education Teachers And Its Relationship To Distributed Leadership, Emma L. Jones

Theses and Dissertations--Educational Leadership Studies

This study examined the relationship between collective teacher efficacy (CTE) and distributed leadership practices among elementary special education teachers. CTE reflects teachers’ shared belief in their collective ability to improve student outcomes, while distributed leadership emphasizes shared decision-making, collaboration, and shared responsibility across school personnel.

Using a sequential explanatory mixed-methods design, the study combined survey data from the Collective Teacher Belief Scale with follow-up interviews. Survey results from 31 special education teachers indicated moderate to high levels of CTE, with slightly greater confidence in managing student behavior than in delivering instruction. Interviews with teachers across varying CTE levels provided deeper …

Comparison Of Machine Learning Models For Colon Cancer Survival: Predictive Modeling Approach, Reuben Adatorwovor, Motolani E. Ogunsanya, Bin Huang, Richard Charnigo, Olufunmilola Abraham

Biostatistics Faculty Publications

Background: Colon cancer is a leading cause of cancer-related deaths worldwide, with survival influenced by risk factors, treatment type, and patient characteristics. Traditional statistical models, such as Kaplan-Meier curves, have been widely used to estimate survival probabilities. However, these models often have difficulty handling complex interactions, covariates, and nonlinear relationships between risk factors. Recently, machine learning (ML) techniques have emerged as promising tools for improving survival prediction by handling large covariates and capturing complex patterns.

Objective: This study compares several ML models to accurately estimate colon cancer survival by leveraging data from the Kentucky Cancer Registry. By identifying key risk …

Disentangling The Inverse Relationship Between Cancer And Alzheimer’S Or Parkinson’S Disease: A Systematic Review On Mendelian Randomization Studies, Khine Zin Aung, Su Su Zin, Xian Wu, Zin W. Myint, Shama D. Karanth, Steven Estus, Christopher M. Norris, Peter T. Nelson, David W. Fardo, Erin L. Abner, Yuriko Katsumata

Biostatistics Faculty Publications

Introduction

Although studies have reported an inverse relationship between cancer and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD), findings remain inconsistent. Observational studies are limited by survival bias and reverse causation. To better understand the relationship, we conducted a systematic review of Mendelian randomization (MR) studies examining both directions—assessing cancer as a risk factor for AD or PD, as well as AD or PD as exposures influencing cancer risk.

Methods

We systematically reviewed MR studies investigating the causal relation between cancer and either AD or PD. Cancer could be specified as either an exposure or an …

Incident Atherosclerotic Cardiovascular Disease Among Veterans By Gender Identity: A Cohort Study, Carl G. Streed Jr., Meredith S. Duncan, Kory R. Heier, T. Elizabeth Workman, Lauren B. Beach, Guneet K. Jasuja, Hill L. Wolfe, Landon D. Hughes, John R. O’Leary, Melissa Skanderson, Joseph L. Goulet

Biostatistics Faculty Publications

Background: Transgender and gender diverse (trans) populations are at elevated risk for atherosclerotic cardiovascular disease (ASCVD).

Objective: Measure the association of gender identity and gender-affirming hormone therapy (GAHT) with ASCVD outcomes.

Design: Cohort study.

Participants: Over 1 million veterans receiving care in the Veterans Health Administration.

Main Measures: Gender identity was identified via a validated natural language processing (NLP) algorithm. Incident ASCVD (acute myocardial infarction, ischemic stroke, or revascularization after the baseline date) was identified via International Classification of Diseases diagnosis codes among veterans without prevalent ASCVD. We calculated sample statistics stratified by gender identity and used Cox proportional hazard …

A Qualitative Study: Supports Enabled By K-8 School Leaders To Bolster The Success Of Teachers In Their Mathematics Departments, Elizabeth A. Mercurio

Theses and Dissertations--Educational Leadership Studies

Despite decades of national policy efforts and reforms, mathematics achievement in public education in the United States, particularly in urban areas, remains persistently low, underscoring the critical need for effective leadership and targeted professional development to maximize student learning. There is limited research on the leadership approaches of building-level school leaders who have effectively strengthened mathematics departments and enhanced teacher capacity to improve student achievement. This qualitative study employed semi-structured interviews with building-level school leaders who have demonstrated success in fostering highly effective mathematics instruction to examine the leadership styles of effective urban school leaders and their use of professional …

Path-Goal Leadership Dynamics In Advanced Manufacturing Dual Credit Career And Technical Education (Cte) Classrooms In Connecticut, Kyle R. Pepin

Theses and Dissertations--Educational Leadership Studies

This dissertation examined the adaptive instructional leadership practices of instructors teaching dual credit career and technical education (CTE) classes in Connecticut, particularly in advanced manufacturing technologies (AMT). The study drew on survey responses from a broader group of course instructors and a purposeful sample of six instructors and six adult students who participated in semi-structured interviews. All instructors taught dual credit classes in partnership with Connecticut State Community College in hands-on manufacturing, engineering, or similar workshop environments designed to prepare high school aged students for careers and develop practical, job-ready skills in settings that closely replicate industry conditions. This under-researched …

Optimizing The Challenge: A Study On Promoting Intrinsic Motivation In Youth Physical Activity, Fan Zhang Dr.

Theses and Dissertations--Kinesiology and Health Promotion

This study investigates the intricate relationship between intrinsic motivation and various factors within the context of physical education (PE) among high school students. Drawing upon Self-Determination Theory as a conceptual framework, the study aims to unravel the influence of perceived challenge, perceptions towards physical activity (PA) during PE, personal characteristics, gender differences, PA levels, and their interactions on students' intrinsic motivation in PE.

A quantitative approach was adopted, utilizing surveys including the Challenge Scale, Intrinsic Motivation Inventory, Relatedness Scale, and Physical Activity Questionnaire for Adolescents. Data was collected from a convenience sample of 92 high school students from Great Crossing …