Digital Commons Network^™

Mathematical Modeling Of Cyber-Physical Attacks In Iot Systems: An Epidemiological Approach, Tunde Alesinloye

Theses and Dissertations

The Internet of Things (IoT) has made electronic devices more interconnected, which has increased cybersecurity threats while also bringing previously unimaginable convenience. In this study, we explore the dynamics of malware transmission in IoT systems using a mathematical modeling methodology that draws inspiration from epidemiological approaches. To better characterize contemporary cyber-defense tactics like honeypots and proactive device hardening, we specifically suggest the SEIR-DX model, which expands the traditional SEIR framework by adding two extra compartments: Deceptive (D) and Secured (X).

The transitions between the six compartments Susceptible, Exposed, Infected, Recovered, Deceptive, and Secured are described by a system of nonlinear …

The Influence Of Active Galactic Nuclei (Agn) Feedback On Star Formation In Spiral Galaxies, Moreom Akter

Theses and Dissertations

We investigate the influence of Active Galactic Nuclei (AGN) feedback on star formation in spiral galaxies by analyzing a sample of 324 red and 273 blue spiral galaxies from 115 low-redshift galaxy clusters. The multi-wavelength dataset combines optical emission line data from the Sloan Digital Sky Survey (SDSS), X-ray luminosity from the Chandra X-ray & XMM-Newton observatories, and ultraviolet (UV) and infrared (IR) measurements from GALEX and WISE. Using diagnostic emission line ratios, we constructed Baldwin, Phillips, and Terlevich (BPT) diagrams to classify galaxies based on nuclear activity. Our analysis reveals that most of the red spirals have AGNs and …

Machine Learning-Guided Discovery Of Metal-Ligand Catalysts For Affordable Green Hydrogen Produced Via Proton Exchange Membrane Electrolyzers, Achouak Benarbia

Theses and Dissertations

The rising demand for clean and sustainable energy sources has underscored the critical role of hydrogen in the global energy transition. However, the widespread adoption of green hydrogen remains constrained by the high cost and scarcity of platinum-based electrocatalysts used in Proton Exchange Membrane (PEM) electrolyzers. This dependence inflates production costs and poses long-term risks related to supply security and scalability. While numerous studies have explored alternative materials, the discovery of efficient and stable non-platinum catalysts remains a major bottleneck due to the vastness of chemical space and the resource-intensive nature of experimental screening. To address this challenge, this study …

Next-Gen Device For Uniform Cellular Migration Assay Execution, Nicholas M. Bittner

Theses and Dissertations

Cellular migration assays, particularly scratch assays, are pivotal in biomedical research for cell motility, wound healing, and metastasis. However, conventional scratch assays suffer from variability due to operator dependence, non-uniform scratch geometry, and a modified microenvironment that impacts reproducibility. This thesis presents the development and validation of a low-cost, 3D-printed device designed to standardize cellular migration assays. The device utilizes a spring mechanism and a biocompatible elastomer to create a uniform cellular exclusion zone without harming the surrounding cells. Through iterative prototyping and testing with MCF10A cell lines, the device demonstrated a significantly lower average standard deviation of length compared …

Autonomous Corrosion Detection In Steel Structures Using Different Non-Contact Techniques, Amrita Das

Theses and Dissertations

Metallic corrosion is an electrochemical process that can occur due to the formation of aqueous adlayers on the metal surface. It is often described as reverse metallurgy, as corrosion drives refined metals back to their lowest energy state, namely an oxidized, ore-like form. Environmental factors that promote corrosion include precipitation, high humidity, and chemical condensation, which can result from the hygroscopic nature of pollutants deposited on the surface. There is a significant impact of metallic corrosion on the U. S. economy including infrastructure, transportation, utilities, production, and manufacturing. The total direct cost of corrosion in the United States has been …

Learning To Teach Digital Literacy: Faculty As Learners, Nicole Marie Maier Derenne

Theses and Dissertations

Rapid developments in artificial intelligence technologies and widening digital divide inequities have made digital literacy instruction an urgent priority in higher education. This qualitative, interpretive case study examined how faculty learned to teach Digital Information Literacy at an instructional development workshop facilitated by academic librarians, following a mandate to integrate digital literacy into the institution’s general education program. Using transformative learning theory as a framework, data were collected from a purposive sample of faculty, librarians, and administrators involvedin the workshop through field notes, interviews, a focus group, document reviews, and journaling, and then hermeneutically analyzed. Findings revealed that although demonstrations …

Gender-Based Perceptions Of Confronting Prejudice In The Classroom, Mary Hamilton

Theses and Dissertations

Disparities exist between men and women in academia at the faculty and student level. Academically, women are judged as being weaker and inferior, and many describe experiences of sexism, often within the classroom setting. Few studies have investigated the impact of an instructor confronting sexism in the classroom. The current study examined the effects of an instructor’s gender, student’s gender, and instructor’s confrontation decision on students’ perceptions of the instructor, classroom environment, and the moderating effect of self-reported sexism. Participants read one of four vignettes describing an act of sexism in the classroom where a male (or female) instructor confronts …

Enhancing Green Hydrogen Integration In Distributed Energy Systems, Solomon Evro

Theses and Dissertations

This study investigates strategic integration of green hydrogen into Distributed Energy Systems (DES) as a means of addressing three closely related challenges: first, uncertainties in hydrogen supply due to renewables intermittency; second, non-existence of practical, scalable modeling solutions for early-phase DES planning involving Alkaline Water Electrolyzers; and third, a lack of sufficient policy frameworks facilitating mass deployment. Existing hydrogen production models are often too complex for effective use in DES and do not relate stack number, input power, and renewable resource fluctuation. To address this limitation, the paper introduces a new probabilistic electrolyzer sizing method based on cumulative distribution function …

An Explainable Ai Framework For Detecting Harmful Algal Blooms (Habs) In Freshwater Lakes, Meera Gopinath Sujatha

Theses and Dissertations

The increase in economic impacts due to the rapid growth of harmful algal blooms (HABs) in freshwater lakes has prompted the development of monitoring and prediction systems. However, limited target data hinders reliable predictions on HAB formations. To address this limitation, this dissertation focuses on providing solutions through data-driven,interpretable, and explainable machine learning models. In Chapter 3, an interpretable multivariate regression model such as Vector Autoregressive (VAR) was used to analyze the important factors that contribute to the formation of cyanobacteria in lakes. The causality tests performed on multiple water quality data helped to determine Alkalinity, Chlorophyll-a (Chl-a), andWater Temperature …

Exploring Geothermal Energy Development In The Deep Reservoirs Of The Williston Basin: An Integrated Analysis Using Empirical, Probabilistic, Numerical Simulation And Machine Learning Techniques, Emmanuel Gyimah

Theses and Dissertations

Geothermal energy, a renewable, clean, and abundant energy source, is gaining global attention as a key contributor to the transition towards a low-carbon economy. However, uncertainties in reservoir characterization and development risks hinder its widespread adoption, particularly in the Williston Basin. This study focuses on the Williston Basin, particularly the Red River and Deadwood formations, to explore the potential of deep geothermal reservoirs in North Dakota. The study integrates a multi-disciplinary technique in empirical, probabilistic, numerical simulation, and machine learning to reduce uncertainties and risks associated with geothermal energy exploration and development. Probabilistic methods (Parametric and Monte Carlo), incorporating geo-statistics, …

Inorganic Arsenite [I-As (Iii)] Represses Human Renal Progenitor Cell Characteristics And Induces Neoplastic-Like Transformation, Md Ehsanul Haque

Theses and Dissertations

Studies on populations exposed to inorganic arsenic (iAs) have shown an association between this particular exposure and the development of chronic kidney disease (CKD) and renal cell carcinoma (RCC). However, there are few studies addressing how acute exposure of the human kidney to iAs might lead to long-term alterations that might lead to CKD or RCC. This study’s hypothesis is that renal exposure to iAs might alter the renal cells responsible for the repair and regeneration of nephrons damaged by iAs exposure or other renal toxicants. The kidney possesses a minority epithelial cell population that co-express PROM1 and CD24 that …

Belongingness And Science Identity Of Underrepresented Students In Aerospace Sciences, Bella Hettich

Theses and Dissertations

Despite efforts to support underrepresented individuals—specifically those from racial, ethnic, and gender minority groups—they continue to face unique challenges that affect their belongingness in aerospace sciences, leading to issues with retention in educational programs and subsequent professional pathways. Such hindrances to personal achievement can also impede broader organizational goals. Addressing these challenges is critical, as supporting the success of underrepresented individuals fosters diverse perspectives, which are essential for driving innovation and maximizing organizational productivity. Just as importantly, ensuring that every individual, regardless of background, has access to opportunities and the support needed to succeed fulfills an ethical obligation. Upholding the …

Hybrid Energy Storage Systems For Renewable Integration: Combining Batteries, Supercapacitors, And Flywheels, Tanwa Morohunkeji Iwayemi

Theses and Dissertations

Renewable energy integration into existing power grids is crucial for a sustainable future, but its intermittency poses technical challenges to grid stability and reliability. Hybrid Energy Storage Systems (HESS), combining lithium-ion batteries, supercapacitors, and flywheels, offer a promising solution by leveraging the complementary strengths of these technologies. This study explores optimal configurations of HESS using HOMER Pro software and a theoretical analysis approach to establish unified mathematical models for the three storages with constraints to address various operational scenarios, including normal operation, absence of renewable sources, and component failures. The proposed system integrates an Energy Management System (EMS) using a …

Thermally Induced Evolution Of The Cement Microannulus In Co2 Injection Wells, Jawad Ali Khan

Theses and Dissertations

Ensuring wellbore integrity during CO₂ injection is a critical challenge in Carbon Capture and Storage (CCS), as failures at the casing-cement and cement-formation interfaces can create potential leakage pathways. This dissertation presents a multi-scale, physics-based investigation into well integrity risks, integrating finite element analysis (FEA), thermal-mechanical-poroelastic modeling, and transient stress analysis to evaluate cement sheath stability, fracture-driven stress localization, and microannulus formation under various CCS conditions.

A key novelty of this research is the development of a fully coupled thermal-mechanical-poroelastic FEA framework using COMSOL Multiphysics, a renowned industry-standard software for multiphysics simulations. This model enables a dynamic, time-dependent assessment …

A Federated Learning Solution For Secure And Scalable Edge Computing In Distributed Environments, Muhammad Hamza Karim

Theses and Dissertations

The growing penetration of Distributed Energy Resources (DERs) into the modern power system has introduced significant challenges related to data volume and cybersecurity. Centralized approaches struggle to process the large volume of data generated by inverters or other DER-related assets securely and efficiently. This problem raise concerns about the confidentiality, integrity, availability, and accountability (CIAA) properties of DER assets. Moreover, the large deployment of Internet of Things (IoT) and edge computing devices has introduced new security vulnerabilities. Malicious actors can exploit resource-constrained edge devices for unauthorized activities and resource consumption, threatening the performance and operational capabilities of the edge infrastructure. …

The Role Of Student Loan Debt On Delayed Homeownership Among Black American College Graduates, Dedan Makongoro Kusaga

Theses and Dissertations

The growing burden of student loan debt in the United States has raised significant concerns about its broader social and economic impacts, particularly on young adults’ ability to achieve financial milestones such as homeownership. Black American college graduates are especially affected, often carrying higher loan balances and facing greater financial barriers due to historical and structural inequalities. This quantitative study examined the role of student loan debt and other factors influencing delayed homeownership among Black American college graduates, using the public-use Baccalaureate and Beyond (B&B: 2008/2018) dataset from the National Center for Education Statistics (NCES). Findings indicated student loan debt, …

Creating Equitable Employment Practices For Adjunct Faculty: Perceptions Of Academic Administrators At Public Institutions In A Great Plains State, Constance Mciver

Theses and Dissertations

Adjunct faculty are a substantial feature of the higher education classroom. Their increased prevalence has contributed to elevated concerns regarding the employment practices of these part-time faculty. While numerous published accounts of adjunct faculty experiences are available, recorded perceptions of academic administrators are less prevalent. Eighty-six academic administrators from six public universities in a Great Plains state participated in a researcher-developed survey to determine the expectations placed upon and compensation practices for adjunct faculty, as well as perceptions of the strengths and weaknesses of the adjunct system and the feasibility of providing more equitable compensation. Survey findings suggest there is …

White Paper For Faculty Professional Development In Establishing, Addressing, And Informing, To Promote Mental Wellness For Health Careers Students, Betty J. Mcvay

Theses and Dissertations

This research utilized a qualitative case study to explore the need for faculty professional development in the health careers division at a public non-profit California community college, specifically Porterville College. Literature suggests that mental health is a crucial topic to address in contemporary higher education. College students, in general, are facing a notable deterioration in their overall mental well-being, accompanied by an increase in mental disorders. Furthermore, students in health careers programs frequently encounter even more intense stress and psychological challenges, stemming from their constant exposure to high-pressure, emotionally charged situations, and vicarious trauma. Although literature emphasizes the critical need …

Geothermal Sweep Efficiency Enhancement Potential Analysis Using Geological Modeling And Numerical Simulation On Unconventional Deadwood Formation, Ashraf Mohammed

Theses and Dissertations

This study investigates the potential to enhance geothermal sweep efficiency in the fractured, low-permeability Deadwood Formation using a cellulose-based biopolymer and gel treatment. A geological model was developed using well log and structural data from four wells in the Williston Basin and subsequently upscaled into a numerical reservoir simulation in CMG/STARS. Laboratory core-flooding experiments on Deadwood samples were used to calibrate gel behavior under high-temperature (160 °C) and high-salinity (17% TDS) reservoir conditions.Simulation results indicate that a short-duration gel treatment—equivalent to 0.03 pore volumes over one year—can significantly reduce channeling through high-conductivity fractures. The reduction in channeling improves thermal conformance …

Seismic Design And Ductility Evaluation Of Concrete-Filled Thin-Walled Steel Tubular Columns Modeling As Bridge Piers, Njiru Mwaura

Theses and Dissertations

Accurate numerical modeling is essential for evaluating the seismic performance and load-bearing behavior of partially concrete-filled thin-walled steel tubular columns, particularly those used as bridge piers under complex seismic conditions. This study investigates the performance of such columns enhanced with embedded energy-dissipating shell plates and/or partial concrete infill, subjected to unidirectional and bidirectional seismic loading. A validated finite element model (FEM), developed in ABAQUS and incorporating geometric and material nonlinearities—including the modified Two-Surface Model (2SM)—was employed to simulate cyclic behavior and predict structural response.The model was benchmarked against experimental results and used to analyze a broad range of parameters, including …

Evaluating Human Factors In Isolation And Confinement During Analog Spaceflight: A Decadal Survey Assessing Ilmah Crew Psychology, Travis Michael Nelson

Theses and Dissertations

This study examined 13 crews participating in analog Martian surface simulations to investigate psychological experiences within the first collegiate planetary surface habitat. The University of North Dakota (UND) Integrated Lunar-Martian Analog Habitat (ILMAH) was utilized with high-performing participant crews (n=42) who were recognized and recruited for their skills. Common environmental similarities that each crew faced included isolation, confinement, time-latent communications, demanding work hours, monotonous tasks, physically strenuous Extravehicular Activities (EVA), personal psychological adaptations, and interpersonal psychosocial challenges. The primary objective of this study was to evaluate self-appraised crew performance measures across continuous phases of isolation and confinement lasting up to …

Investigation Of Surfactant-Enhanced Oil Recovery In High Salinity And High Temperature (Hsht) Reservoir Conditions: A Case Study In The Bakken Formation, Tomiwa Isaac Oguntade

Theses and Dissertations

This study investigates improved strategies for enhancing oil recovery (EOR) in challenging reservoir conditions by combining chemical surfactant flooding and data-driven optimization techniques. Given rising global energy demand and the depletion of conventional oil reserves, chemical EOR methods, particularly surfactant flooding, are gaining popularity for their ability to mobilize residual oil via mechanisms such as reducing interfacial tension, altering wettability, and inhibiting asphaltene formation. The research begins by examining the effectiveness of surfactant applications across various reservoir conditions, emphasizing the need for surfactants capable of withstanding challenging environments characterized by high temperatures, high salinity, and low permeability. Laboratory experiments demonstrated …

Evaluating The Engineering Properties Of Waste-Modified Asphalt Binders And Mixtures As Inputs For The Mechanistic-Empirical Pavement Design, Duncan Rioba Oteki

Theses and Dissertations

Pavements are essential for economic development and mobility, with asphalt dominating the US road network due to its cost-effectiveness, ease of maintenance, and recyclability. However, the environmental impacts of asphalt production and the depletion of virgin materials have driven the integration of waste products into asphalt mixtures to improve sustainability. This study evaluated the engineering properties of waste-modified asphalt binders and mixtures as performance-based inputs for the Mechanistic-Empirical Pavement Design Guide (MEPDG). The rutting performance of ten asphalt mixtures commonly used in North Dakota was assessed using mechanistic and empirical tests. Mechanistic tests included the dynamic modulus (|E*|), Flow Number …

High-Fidelity Surface And Environment Simulation Using Immersive Virtual Reality For Lunar Analog Training, Shriya Pedaparthi

Theses and Dissertations

The study explores the integration of high-fidelity Virtual Reality (VR) into astronaut training for lunar analog missions. A realistic VR simulation was developed to represent lunar terrain, allowing participants to perform critical tasks under simulated lunar conditions. Specifically, participants navigated from a compromised lunar habitat (ILMAH) facing a pressure breach, to a secure facility, testing their ability to respond effectively to emergency scenarios. Participants underwent three sequential trials to assess how VR and physical constraints influence gait and performance: (1) a baseline trial measuring natural gait without equipment; (2) a trial incorporating a real spacesuit and lunar gravity simulated through …

Comparative Study Of Robotic And Manual Welding For Energy Consumption And Efficiency In A High Mix, Low Volume Manufacturing Environment, John Ruprecht

Theses and Dissertations

This study examines the comparative efficiency and energy consumption of manual versus robotic welding in high-mix, low-volume (HMLV) manufacturing environments. Traditional robotic welding systems have been predominantly used in low-mix, high-volume production due to their efficiency in repetitive tasks. However, the advent of collaborative robots (cobots) has democratized robotic automation for diverse manufacturing needs. Cobots allow flexibility in programming, enabling their deployment in HMLV environments characterized by hard product variety and smaller batch sizes. This research evaluates energy consumption, welding speed, and quality metrics across manual and cobotic welding systems. Data were gathered using energy meters and video analysis, focusing …

Integrating Seismic Attributes And Machine Learning For Accurate 3d Petrophysical And Geomechanical Modeling In Shale Plays, Rasaki Olaide Salami

Theses and Dissertations

The increasing reliance on shale plays for hydrocarbon production necessitates accurate 3D petrophysical and geomechanical models to optimize resource recovery. However, conventional methods struggle with shale reservoir complexities such as low permeability, anisotropy, and data heterogeneity, leading to uncertainties in property predictions. This dissertation integrates seismic attributes with machine learning (ML) techniques, including Long Short-Term Memory (LSTM) networks, Temporal Convolutional Networks (TCNs), and Wasserstein Generative Adversarial Networks with Gradient Penalty (WGAN-GP), to enhance predictive accuracy.LSTMs and TCNs effectively capture temporal dependencies, while WGAN-GP generates high-quality synthetic data to mitigate data scarcity. The study critically evaluates existing 3D modeling methodologies, identifying …

Experimental And Numerical Modeling For Co2 Utilization In Enhanced Oil Recovery And Associated Storage In Unconventional Reservoirs, Billel Sennaoui

Theses and Dissertations

Unconventional reservoirs, such as the Bakken and Three Forks formations, present significant challenges due to their ultra-low permeability and complex fracture networks, which limit primary oil recovery to less than 10%. To enhance hydrocarbon extraction while simultaneously facilitating carbon dioxide (CO₂) storage, this study investigates the mechanisms governing CO₂ Huff-n-Puff (HnP) and associated storage under various operational conditions. A comprehensive approach integrating experimental analysis, numerical simulations, multiphase flow modeling, and geochemical interactions is employed to optimize CO₂-EOR and storage strategies. The experimental phase focuses on evaluating the performance of different injected gases (CO₂, ethane, and propane) in the Upper Three …

Forceful Functors: A Categorical Approach To Constraint Monitoring In Machine Learning Models, Jonathan Wirkkala

Theses and Dissertations

Often times in machine learning there are several heuristic choices that one makes during model selection, training, and validation. These choices include the type of training used, the width and depth of the model, type activation function and many more. These choices are general rules of thumb and best practices when creating a machine learning algorithm to achieve acceptable results. For example, in the case of image processing, this may mean determining whether or not a given image contains a tumor. Decisions made during the design process create several variations of machine learning algorithms, all with various properties with pros …

Stem Professors’ Motivation To Engage In A College Teaching Certificate, Justin Craig Alexander

Theses and Dissertations

Despite an expanded focus on educating students in STEM disciplines, nearly half of U.S. college students who enroll in these degree programs fail to graduate (Hamm et al., 2020, p. 623). Critics sometimes blame pedagogically untrained faculty (e.g., Kahn, 2022). This Dissertation in Practice (DiP) focused on STEM university faculty's motivation for teaching and whether professors are motivated to enroll in pedagogy courses. Via the lens of self-determination theory (SDT), this DiP examined to what extent STEM faculty at a major research university in the upper Midwest could devote additional time to pedagogy by enrolling in a college teaching graduate …

Concept Application Of Active Magnetic Bearing Technology For Offshore Horizontal Axis Wind Turbines, Isaac Ansah

Theses and Dissertations

Wind energy continues to lead the global transition to renewable power, driven by its minimal environmental impact and high scalability. Offshore wind farms benefit from stronger and consistent wind resources. However, these advantages are tempered by challenges related to installation, maintenance, and drivetrain reliability. Conventional bearings, which support the drivetrain system, are prone to wear related failures due to lubrication breakdown and mechanical fatigue from continuous loading. This study explores the integration of Active Magnetic Bearings as an alternative to conventional bearings in offshore Horizontal Axis Wind Turbines. Using advanced engineering simulation tools, the main driveshaft of a 130 MW …