Digital Commons Network^™

A Visit-Count-Based Complete Foraging Strategy For Robot Swarms, Arturo Yahir Gonzalez

Theses and Dissertations

Swarm robotics systems often rely on a balance between exploration and exploitation to perform tasks like Central Place Foraging. While exploitation methods such as pheromone trails and site fidelity are well-studied, the efficiency of the underlying random search exploration remains a challenge, frequently leading to redundant coverage and wasted time as multiple agents repeatedly search the same fruitless areas. This thesis introduces a memory-enhanced exploration strategy designed to improve the efficiency of random search in a swarm of simple robots.

In our proposed algorithm, each robot, constrained with limited memory, periodically logs its recent locations while exploring. This spatial data …

The Role Of Operational Context In Shaping Energy Management Portfolios: A Comparative Case Study Of Two Manufacturing Facilities, Cynthia Aranda

Theses and Dissertations

Using two facilities as illustrative examples, this research investigates how a manufacturing plant's operational and financial context may influence its investment decisions in energy-efficiency measures. This challenges the primacy of the simple payback period (SPP) as a screening tool and instead demonstrates the role of operational context in investment decision-making. To this extent, this study is anchored to a qualitative comparative case study analysis of two ITAC energy assessments for two manufacturing plants in Texas: a higher value-added aerospace MRO plant (GE Aerospace, TR0060) versus a cost-sensitive automotive stamping plant (UMP Metal Stamping, TR0061). The two cases illustrate two different …

Spatiotemporal Evolution Of Flow Decline And Water Consumption In A Highly Regulated Transboundary River: The Lower Rio Grande/Bravo, Ana Yarely Casillas Rodriguez

Theses and Dissertations

Long-term flow variability in transboundary rivers reflects the combined influence of water availability, infrastructure development, and binational water use. Integrating historical discharge with evolving water-use data remains challenging due to fragmented records and nationally bounded assessments. This study reconstructs a 125-year discharge record (1900–2025) from historical Water Bulletins and modern observations at 12 gauging stations, providing a spatiotemporal assessment of flow evolution and water-budget components in the Lower Rio Grande/Bravo (LRG).

Discharge records were grouped into four hydrologic regimes—natural (1900–1913), pre-dam (1935–1950), post-dam (1974–1989), and modern (2010–2025)—and analyzed alongside binational water-use data across major sectors. A basin-scale water budget, using …

Probing The Dynamic Behavior Of The Androgen Receptor In The Presence Of Heptyl And Methyl Parabens, Edgardo De Leon

Theses and Dissertations

The androgen receptor (AR) mediates physiological signaling from endogenous androgens, a function that can be disrupted by endocrine disruptors with serious reproductive and developmental consequences. Parabens, widely used preservatives, inhibit AR signaling in cell-based assays, with inhibitory potency correlating with alkyl chain length: heptylparaben exhibits stronger antagonism than methylparaben, which shows no effect. We hypothesize this differential potency arises from allosteric modulation at the AR Binding Function 3 (BF-3) site, altering dihydrotestosterone (DHT) binding dynamics. Docking calculations using antagonist-bound AR crystal structures, followed by molecular dynamics simulations, show that methylparaben fails to remain bound at BF-3, whereas heptylparaben maintains stable …

A Testimoniando On Tutoring Practices In A Predominantly Latine Writing Center: How Drawing From Tutors’ Memories Fosters Reflective Practices, Emily Michelle Rodriguez

Theses and Dissertations

The student body of the University of Texas Rio Grande Valley (UTRGV) consists primarily of Latine students, a population that is reflected in the Writing Center’s tutor demographics. Tutor practices connect to the training sessions that are based on disciplinary expectations but also incorporate each tutor’s epistemology, cultural beliefs, and lived knowledge experiences. To reflect on the practices, memories, and experiences that tutors collected at the Writing Center, the concepts of testimoniando and testimonios will serve as the praxis and means of sharing the experiences and lived knowledge of tutors who identify as part of a marginalized group; this allow …

Morphological Evolution And Sediment Budget Of A Flood-Tidal Delta On The Rio Grande Delta Plain: Bahia Grande, Texas, Usa, Aleen Pertuz Paz

Theses and Dissertations

The Isabel Delta is a recently formed flood-tidal delta within the restored Bahia Grande system on the Rio Grande Delta Plain, Texas, USA, where renewed tidal connectivity has created conditions for rapid sediment buildup and landform evolution. This study quantified morphological changes from 2008 to 2025 using satellite imagery. It assessed sediment retention by comparing the effective sediment discharge required to reproduce observed delta growth with field-based estimates of sediment supply derived from channel hydrodynamics, cross-sectional area, and suspended sediment concentration. The delta expanded steadily throughout the study period, with increases in bar, channel, and total surface area, and an …

Sub-Ghz Propagation Along Freight Trains For Wireless Onboard Communications, Dario Hinojosa

Theses and Dissertations

With the increasing length of freight trains, maintaining reliable wireless communication for onboard sensors has become increasingly challenging. Sub-GHz communication bands are a promising solution due to their long-range capability and suitability for rural railway environments. This study analyzes radio wave propagation around freight railcars to evaluate path loss and determine how antenna polarization affects wireless communication performance.

Time-domain full-wave electromagnetic simulations were performed using simplified railcar models and later validated through field testing using a vector signal generator, vector network analyzer (VNA), and spectrum analyzer. Various antenna polarization configurations were evaluated within the Sub-GHz Long Range (LoRa) frequency band …

Soil Water Content Beneath Agrivoltaic Installations In A Subtropical Semi-Arid Climate, John Justin Rodriguez

Theses and Dissertations

Agrivoltaics (AV) not only beneficially influences agricultural microclimates in the field, AV systems can generate on-site energy to offset operational costs, diversify income sources, and improve overall resilience, while providing environmental co-benefits such as reduced heat stress on plants and improved resource use efficiency. This thesis evaluated agrivoltaic shading effects on SWC and soil temperature using high-resolution in situ measurements collected over one year in an active vineyard, incorporating row type, soil depth, shading, and time of day. With precipitation as the primary water source, shaded soils exhibited up to 24.53% lower SWC relative to sun-exposed soils, likely due to …

Multivariate Time-Series Forecasting Of 24-Hour Ambulatory Blood Pressure Using Long Short-Term Memory And Temporal Fusion Transformers, Sebastian Alejos Torres

Theses and Dissertations

Time series play a central role in healthcare by enabling continuous patient monitoring and forecasting of physiological and clinical measurements. Traditional models, such as autoregressive integrated moving average (ARIMA), are limited in capturing nonlinear dynamics and irregular sampling. In this study, we develop and evaluate Long Short-Term Memory (LSTM) networks and Temporal Fusion Transformers (TFTs) to forecast 24-hour ambulatory systolic and diastolic blood pressure (SBP and DBP) time series enriched with demographic and clinical features. Mean absolute error (MAE), root mean squared error (RMSE), mean absolute percentage error (MAPE), and R² were used to evaluate predictive accuracy and temporal pattern …

Structure–Property Engineering Of Sn-Based Hybrid Perovskites Via Bulky Organic Cation Incorporation: From 3d To 2d Architectures, Kevin Alejandro

Theses and Dissertations

This thesis investigates tin-based hybrid organic/inorganic perovskites (HOIPs) as a lead-free alternative to silicon solar cells. To manipulate optoelectronic and efficiency of the semiconductors, methylammonium was substituted with bulky propylammonium and tetrabutylammonium cations to induce quasi-2D/3D Ruddlesden-Popper phases. X-Ray Diffraction confirmed 2D layered phases in propylammonium hybrids (5-15%), while tetrabutylammonium hybrids faced steric limits, triggering vacancy ordered perovskite phases at 1% concentration. Optical analysis showed a bandgap narrowing from 1.30 eV to 1.26 eV with increased substitution. Although photovoltaic performance generally declined, the 10% propylammonium hybrid achieved the highest fill factor of ~0.79, indicating superior internal charge transport. This work …

Writing And Witnessing Ourselves Into Being: Testimonios Of A Chicana Educator And Latine Students For Social Justice In A Writing Course At A Hispanic Serving Institution, Amy Montoya

Theses and Dissertations

A qualitative study of first-year writing students at a Hispanic Serving Institution (HSI) sought to understand the extent to which the practice of writing testimonios transformed how students constructed their sense of identity for social justice. Guided by the research question: How does the practice of writing testimonios in a writing course at an HSI shape faculty and student identity for social justice? This qualitative study analyzed the lived experiences of three former Latine female undergraduates and the researcher in a co - participatory testimonio methodology study. Grounded in the conceptual frameworks of decolonization (Mignolo & Walsh, 2018; Paraskeva, 2013) …

Reactive-Fluid-Transport Controls On Co2-Eor Applications In The Upper Red River Carbonate Reservoir, Abdelmalek Abes

Theses and Dissertations

Reactive-transport phenomena during CO2 injection in carbonate reservoir were examined in detail. Three core samples from the primary producing units of North Dakota’s Upper Red River Formation (U2-H055, U4-H069, and U6-H009) were used to experimentally investigate geochemical reactions and petrophysical alterations, impacting carbon dioxide enhanced-oil-recovery (CO2-EOR) and geologic-carbon-storage (GCS) projects. During corefloods using a CO2/brine mixture, two samples demonstrated early permeability increases followed by declines, whereas the third sample demonstrated an early decrease; all samples gradually recovered at a later stage. Nuclear magnetic resonance (NMR) measurements revealed slight porosity increases due to dissolution-induced wormholes, while the pore-size distribution (PSD) shifted …

Towards Continuous Carbon Fibers From Corn Oil, Ismail Akanmu Adebayo

Theses and Dissertations

The global demand for carbon fibers has experienced exponential growth over the last decade, driven by the desire for materials with high strength and low density for applications in aerospace, automotive, wind energy, and specialty industrial markets. Currently, carbon fibers are almost exclusively produced from petroleum-based precursors, most commonly polyacrylonitrile (PAN) and petroleum-derived pitch. The high production costs associated with these fossil-based precursors limit the broader adoption of carbon fibers and represent a significant barrier to market expansion. The development of a bio-based carbon fiber precursor derived from renewable feedstocks would help transition this market away from fossil carbon sources …

Student Engagement As A Predictor Of Stem Student Success, Mosab Shaher Abu Al Foul

Theses and Dissertations

This quantitative study investigates factors influencing engagement, persistence, and degree completion among underrepresented minority (URM) students in science, technology, engineering and math (STEM). Guided by Tinto’s Interactionist Model (1975) and Bandura’s Self-Efficacy Theory(1977), it examines how institutional practices and socioeconomic conditions contribute to inequities in student outcomes. Using a non-experimental, correlational design, the study analyzes National Survey of Student Engagement (NSSE) data and institutional records from a Midwestern Research 2 university (N = 620; URM subsample n = 52). Binary logistic regression, MANOVA, and t-tests were used to assess relationships among High-Impact Educational Practices (HIEPs), engagement indicators, faculty interaction, pre-college …

Wifi-Based Teleoperation System For A 3d-Printed Rc Car, Manvel Beaver

Theses and Dissertations

In the field of autonomous vehicle (AV) research, developers often face a significant gap between low-power hobbyist kits and cost-prohibitive industrial platforms. This thesis presents the design, integration, and validation of "Das Mueller," a high-performance, 1/10th-scale unmanned ground vehicle (UGV) designed to provide a transparent and cost-effective testbed for neural network development. By bridging the interoperability gap between the Donkey Car software framework and the 3D-printable Tarmo5 mechanical chassis, this project establishes a modular architecture centered on the NVIDIA Jetson Orin NX single-board computer.

The research utilizes a Model-Based Systems Engineering (MBSE) approach and rapid prototyping to address critical challenges …

A Comparative Study Of Dsmc Codes For Rarefied Atmospheric Re-Entry Applications, Laina Behrenbrinker

Theses and Dissertations

Hypersonic atmospheric re-entry involves complex rarefied flow phenomena, including thermochemical non-equilibrium and plasma formation, which must be accurately predicted to assess vehicle performance and communication blackout. The Direct Simulation Monte Carlo (DSMC) method is applied to model these effects through code-to-code comparison and rarefied re-entry simulation. DSMC codes SPARTA and Comet are compared with a 2D cylinder test case to evaluate consistency in predicted flowfield quantities. This is followed by 2D and 3D axi-symmetric simulation of the Varda re-entry capsule at 78 km altitude to characterize plasma formation. 2D cylinder results show agreement in translational and rotational temperature and neutral …

Additively Constructed Concrete Culverts (Acc), Eugene Kwabena Assuah-Damoah

Theses and Dissertations

Rural culvert systems in cold regions like North Dakota face rising replacement needs due to aging infrastructure, harsh deterioration, and limited precast supply. Additive construction with concrete (ACC) offers promise but is constrained by proprietary mix designs, limited validation for non-linear geometries such as ring-type pipes, and challenges in reinforcement integration. This study addresses these gaps through three efforts. First, a non-proprietary mix (MIX7, w/c = 0.37) using local materials achieved optimal printability (190–200 mm flow) and 28‑day strengths of 55–60 MPa; full-scale 18‑inch pipes met ASTM C76 Class II/III requirements. Second, literature shows ACC permanent formwork performance depends on …

Climate Messages In An Ai-Integrated Experiment: Interpretive Divergence, Policy Support, And A New Resonance Consistency Framework, Jayme Colosimo

Theses and Dissertations

This dissertation examined how environmental frames—particularly “Mother Earth” and “Mother Nature”—influence public support for climate policy and how these effects differ across demographic groups. Using a mixed-methods explanatory sequential design, the study executed a media survey experiment (N = 470) followed by semi-structured expert interviews to assess responses to two primes using a conventional corporate media message, and a message with similar content that was generated by Artificial Intelligence (AI).

Quantitative findings showed that these metaphors generated uneven and sometimes divergent priming effects. Some groups—most notably White male Republicans—reported higher support for environmental policy under the conventional media prime. Under …

Numerical Verification Of A Gpu-Accelerated Particle-In-Cell Code For Low-Temperature Plasma Simulations, Wei Guo

Theses and Dissertations

This thesis presents the numerical verification of Comet, a GPU-accelerated Particle-in-Cell with Monte Carlo Collisions (PIC/MCC) code designed for low-temperature plasma simulations. To ensure efficient deployment across heterogeneous computing architectures, the framework leverages the Kokkos performance-portability layer for high-performance execution. Verification was conducted through a series of hierarchical stages with increasing physical complexity, benchmarking each component of the fundamental PIC/MCC simulation cycle. This structured approach establishes the numerical fidelity of the code's algorithmic building blocks prior to its application in predictive plasma research.

The first stage verifies field interpolation and particle pusher modules against canonical single-particle cases, focusing on ion …

Open Chromatin-Guided Analysis Of Cell-Free Dna For Inferring Regulatory Landscapes In Cancer Detection, Monitoring, And Therapeutic Response, Sakuntha Devaka Gunarathna

Theses and Dissertations

Conventional cancer diagnosis and monitoring rely on imaging and tissue biopsies. Imaging is constrained by resolution, while biopsies are invasive, limited in capturing tumor heterogeneity, and challenging to perform repeatedly over time. Liquid biopsy has emerged as a minimally invasive alternative that enables real-time assessment of tumor-derived material in circulation. Among its components, cell-free DNA (cfDNA) has gained significant attention as a promising biomarker for cancer detection and disease monitoring. However, most current cfDNA approaches rely on mutation- and methylation-based signals, which, while informative, can be limited by low tumor fraction, biological heterogeneity, and reduced sensitivity in early-stage disease. In …

Analyzing Uav Propeller Performance At Various Advance Ratios Using Wind Tunnel Testing And Cfd, Nicholas Holte

Theses and Dissertations

A computational fluid dynamics (CFD) procedure is developed in this thesis to predict the performance parameters of small-scale unmanned aerial vehicle (UAV) propellers and to validate the results against experimental data over various advance ratios. The commercially available Ansys Fluent® software (version 24.2) was used to simulate 19-inch and 14-inch Advanced Precision Composites (APC) Thin Electric propellers each with pitches of 12 inches per revolution. The simulation results were compared to data collected in open-atmosphere wind generator experiments at the University of North Dakota (UND) and also to experimental wind tunnel data from the University of Illinois at Urbana-Champaign (UIUC). …

Machine Learning For Laminar Heat Transfer In Supercritical Fluids, Luke Holtshouser

Theses and Dissertations

In the last 10 years machine learning has become increasingly more used in the field of fluid dynamics and heat transfer. However, with this increase in activity, gaps still exist with respect to supercritical fluids and laminar flows, where laminar flow in general seems understudied. For supercritical fluids, there are many peculiar studies that are isolated to unique systems or they are obscure enough to include everything but the kitchen sink. This strategy provides no real insights into how the field can make further progress in the utilization of the technology available, or rather build-upon previous knowledge. For this reason, …

Redox-Driven Wettability In Underground Hydrogen Storage: Linking Geochemical Speciation, Surface Charge, And Contact Angle, Ijaz Khan

Theses and Dissertations

Underground hydrogen storage (UHS) depends on complex interactions among reservoir rocks, brine, and gas under redox conditions induced by H2 injection. Although wettability is often treated as a static parameter, redox reactions can shift pH, aqueous speciation, and mineral surface charge, thereby altering contact angles and, consequently, injectivity, trapping, and recovery. This work tests the hypothesis that dominant redox pathways in saline aquifers and depleted reservoirs, specifically Fe(III) and sulfate reduction, systematically modify mineral surface stability and charge, producing predictable shifts in wettability. To address this, we developed a physics-guided machine learning workflow that integrates mechanistic geochemical understanding with empirical …

Flipping The Odds: At-Risk Students’ Perceptions Of The Benefits Of The Flipped Classroom Model In High School Mathematics, Roberto Alonzo Moedano

Theses and Dissertations

High school educators tasked with teaching and learning are often challenged to find ways to keep students engaged and ensure they are learning content. However, the COVID-19 pandemic that the United States experienced from 2020 to 2023 (Northwestern Medicine Staff & Northwestern Medicine, 2025) made educators’ efforts more difficult. This unprecedented time of remote teaching and learning transformed the educational landscape overnight. It removed face-to-face learning and replaced it with virtual classes—neither teachers nor students were prepared for the challenges. This research study examines how a flipped classroom approach has the potential to yield positive results at the high school …

Evaluation Of Geothermal Viability In Partially Abandoned And Dry Oil Wells Within The Red River Formation In Williston Basin For Repurposing Into Enhanced Geothermal Systems, Ajan Meenakshisundaram

Theses and Dissertations

Transitioning toward global decarbonization of energy resources necessitates the development of dispatchable baseload resources that leverage existing infrastructure to minimize environmental footprints and capital expenditures. This research investigates the technical and economic feasibility of repurposing unplugged and dry oil and gas wells within the Red River Formation of the Williston Basin in North Dakota for conversion into Enhanced Geothermal Systems (EGS). While immense geothermal resources exist, they are often rendered uneconomical by high drilling costs and a lack of holistic subsurface understanding at target depths. To bridge these gaps, this interdisciplinary study employs a workflow ranging from experimental physics and …

Comprehensive Analytical Approaches To Biophysical And Hard Matter Systems, Carlos Munoz

Theses and Dissertations

In this work we define the methods and experimental techniques that are used in the synthesis, characterization, and development of biophysical and hard matter systems. These efforts encompass six principal areas: Comprehensive characterization of pathogenic bacteria, development of novel chemical methods for probing binding affinities in cellular systems, understanding the electronic properties of silicon/silicon dioxide interfaces, characterization of catalytic perovskite oxide materials, and lastly, heteroepitaxial growth of vanadium nitride thin films on the silicon nitride surface.The Lyme disease spirochete Borrelia burgdorferi (B. burgdorferi) causes an infection with diverse clinical outcomes, which can include arthritis as well as cardiac and neurological …

Modeled Decrease In Wildfire Occurrence In Alaska By 2100, Hayden Patterson

Theses and Dissertations

Wildfire occurrence in Alaska has increased since 1979 due to global climate change. The rising temperatures affect relative humidity, vapor pressure deficit, precipitation, and other factors that lead to the increased ignition of wildfires. Therefore, there is a distinct need for a statewide prediction-model for wildfire occurrence in Alaska. This research modeled the effects of changing humidity on spatial evolution of the predict wildfires out to 2100. We found that the wildfire occurrence area would grow by 65% until 2052 and then would shrink until 2100 by 94%. This suggests that the increasing moisture in the warming air is outcompeting …

Ground Penetrating Radar Spiral Antenna Transient Response Based On Target Radar Cross Section, David Rohde

Theses and Dissertations

This dissertation presents a significant advancement in Ground Penetrating Radar (GPR) detection technology through the development of a novel method for the detection and classification of buried conductive objects using custom-designed Archimedean spiral antennas. The research demonstrates that the transient electromagnetic response of an Archimedean spiral antenna is strongly correlated with the Radar Cross Section (RCS) characteristics of buried objects operating within the radar resonance scattering, or Mie, region. By leveraging this relationship, the proposed approach enables not only the detection of buried objects, but also generalized classification based on object geometry and size.A primary contribution of this work is …

Teachers’ Perceptions Of Their Culturally Relevant Practices Within Stem Education, Focusing On Native American Students, Cortney Ellen Shuley

Theses and Dissertations

This qualitative study examines how culturally relevant practices are perceived and enacted by K-12 STEM educators working with Native American and non-Native American students. Situated within the context of North Dakota’s educational landscape, the research explores both teacher perspectives and curriculum design, with particular attention to the role and integration of the North Dakota Native American Essential Understandings (NDNAEU) within STEM instruction and curriculum design. Using thematic analysis of interviews and photo elicitation with three K-12 teachers who have participated in culturally relevant engineering education, as well as document analysis of NDNAEU and state-standards-aligned STEM lesson plans, the study examines …

Beyond The Manual: Training Troubleshooting Skills Through Augmented Reality, Lawrence Allen Smith Jr.

Theses and Dissertations

Many industrial maintenance departments implement and utilize Augmented Reality Technology (ART) and Augmented Reality Technical Training (ARTT) in their day-to-day operations. This study aims to examine technicians' troubleshooting skills by exploring two main questions: (1) how these skills are impacted by Cognitive Load Theory (CLT), and (2) how they are influenced by using either paper manuals or ARTT manuals. The research will compare the effects of traditional paper manuals and ARTT manuals on the learning outcomes of troubleshooters. The measurements of learning outcomes will include cognitive ability, professional specific knowledge, and skill retention. Keywords: augmented reality (AR), industrial maintenance, augmented …