Digital Commons Network^™

Design And Characterization Of A Jet Nozzle Using Particle Image Velocimetry, Valerie K. Rodriguez

Graduate Studies Theses and Dissertations 2026

This paper presents the design and experimental characterization of the jet exit velocity from a supersonic nozzle injecting into a low-pressure vacuum chamber using Particle Image Velocimetry (PIV). The PIV method is employed to overcome limitations encountered in prior experiments characterizing a jet-in-crossflow, such as qualitative shock visualization and insufficient data on jet exit properties. The previous set of experiments used Classical Schlieren to visualize the flow as well as emission measurement with IR detectors. For the fuel injection cases, particular emphasis is placed on preventing condensation within the injection line and at the nozzle exit due to under expanded …

Monitoring Shifts In Estuarine Microbial Communities: A Dna-Metabarcoding Approach, Ashley M. Reaume

Graduate Studies Theses and Dissertations 2026

Estuarine microbial communities, including plankton, algae, and bacteria, play important roles in nutrient cycling and food web structure. They are sensitive to changes in abiotic conditions, and shifts in community composition can provide insight into estuarine ecosystem functioning in the face of various physiochemical and anthropogenic stressors. Therefore, monitoring these communities is essential for understanding and maintaining estuarine health. DNA metabarcoding is an emerging technique for enhancing biological monitoring, allowing for the detection of multiple species within a single sample. This dissertation first focuses on how methodological decisions impact DNA metabarcoding results and then implements these optimized methods to perform …

Black Mothers' Experiences Of Birth Trauma: A Conceptual Analysis And Mixed-Methods Study To Advance Perinatal Mental Health Counseling, Lisa Rickman

Graduate Studies Theses and Dissertations 2026

This dissertation study follows the manuscript model and consists of two manuscripts, one conceptual manuscript and one empirical study, both focusing on the experiences of Black mothers following psychologically and physically traumatic childbirth. The conceptual manuscript centers birth trauma within the social, historical, and cultural contexts of perinatal mental health disparities and obstetric racism. This framework guides clinicians in centering Black mothers’ needs utilizing Relational Cultural Theory to promote equitable perinatal mental health practice. The empirical study employs a phenomenological sequential mixed methods approach prioritizing interview data collected from Black mothers who experienced birth trauma. This study also explores their …

Shock Tube Speciation Analysis Of Hydrocarbon Mixtures Relevant To Solid Fuel Combustion, Diego N. Ruiz Pena

Graduate Studies Theses and Dissertations 2026

Solid Fuel Ramjets (SFRJs) are often used in tactical applications due to their simplicity, robustness, and reliability. No moving parts, atmospheric oxidizer usage, and scalable fuel grain designs make them a great solution for compact, high-speed air-breathing propulsion systems. SFRJs operate by compressing incoming air through a fixed geometry inlet and directing it over a regressing solid fuel surface, where pyrolysis gases are released and transported downstream to the combustion chamber where thrust is generated. Hydroxyl-terminated polybutadiene (HTPB) is a commonly used fuel binder in SFRJ systems due to its high energy density, stable combustion behavior, and ease of processing. …

A Frequency-Dependent Hydrodynamic Modeling Framework For Offshore Platforms With Optimization-Based Parameter Identification, Md. Rafid-Ul Haque Sakif

Graduate Studies Theses and Dissertations 2026

Accurate prediction of hydrodynamic loads on offshore platforms requires drag coefficients that adequately capture their dependence on wave frequency. However, conventional implementations of Morison’s equation generally assume constant drag coefficients across the entire frequency spectrum, which can lead to inaccuracies in predicting platform responses under complex sea-state conditions. To address this limitation, this study proposes a frequency-dependent hydrodynamic modeling framework in which the platform response is decomposed into distinct frequency regions, specifically low-frequency and high-frequency components. Separate drag coefficients are assigned to each region to better represent the underlying flow physics. The decomposition is achieved using filtering techniques in the …

Modeling Hazard Perception Learning In Novice Drivers With Autism: A Multimodal Simulation-Based Study, Erik J. Sand

Graduate Studies Theses and Dissertations 2026

Young drivers with autism spectrum disorder (ASD) often demonstrate difficulties with road-surveillance behaviors such as scanning ahead, monitoring mirrors, and identifying emerging hazards. These challenges can increase crash risk, particularly for adolescents with limited driving experience. This study explored whether a simple, video-game–based hazard-training program could improve hazard detection performance, visual scanning, and self-regulation in this population. Five participants aged 15–18 years, each identified by a parent as having ASD and possessing either a learner’s permit or no license, completed sequential Baseline, three Treatment, and Withdrawal phases using the SpeedLimit driving simulation. The study employed a single-case experimental design with …

Source Credibility And Chatbots: How Design Factors Impact Chatbot Effectiveness, Kristen M. Schmidt

Graduate Studies Theses and Dissertations 2026

Source credibility theory states that the more credible a source appears to be, the more likely one is to believe both true and untrue information from it. In the modern day, misinformation is considered a major problem, particularly with virtual communication, meaning it is essential to study what factors influence a system’s source credibility. Virtual agents are a particularly relevant subject of study given that their source credibility can be impacted by both technological and social factors. Across three experiments, this dissertation utilized a novel chatbot interaction design to test how varying design factors would impact a chatbot’s source credibility …

Bond Behavior Of Uhpc-Nsc Interfaces For Bridge Deck Repair Under Flexural Loading, Larissa Santiago La Banca

Graduate Studies Theses and Dissertations 2026

The use of ultra-high performance concrete (UHPC) has increased due to its superior mechanical properties and strong bond with normal-strength concrete (NSC). It is widely used as a repair material, particularly in bridge decks, where maintenance remains a challenge. However, the interface between UHPC and NSC is often the weakest region of the composite system and requires careful evaluation.

This study investigates the bond behavior between UHPC and NSC using different surface preparations, test setups, and UHPC materials. The experimental program included unreinforced beams with vertical interfaces tested under three- and four-point flexural loading, and reinforced slabs with horizontal interfaces …

Tl;Dr (Too Long; Didn't Read): Examining The Assessment And Causes Of Careless Responding Within Experimental Vignette Studies, David L. Sexton Jr.

Graduate Studies Theses and Dissertations 2026

Careless responding occurs when participants answer survey items without considering their content and poses a serious threat to data quality. However, while past research has examined its deleterious effects on both survey and low-stakes cognitive ability measures, little research has focused on careless responding in experimental vignette methodology (EVM) research. EVM studies require participants to attend to one or more experimental vignettes, which are carefully crafted written scenarios designed to manipulate a focal variable across conditions. However, if participants are careless in attending to study vignettes, they may not be exposed to the researchers’ intended experimental manipulations, thereby precluding them …

Defect-Guided And Energy-Driven Unfolding With Learning-Based Strategies: From Geometries With Compact Refolding To Garments, Shah Wasif Sazzad

Graduate Studies Theses and Dissertations 2026

Unfolding and folding are related geometric and mechanical transformations fundamental to structural applications. Particularly, unfolding curved surfaces is important for deployable structures, garment pattern generation, etc. A central challenge is minimizing geometric distortion between a surface and its unfolded counterpart avoiding overlaps. As regions of lower Gaussian curvature typically produce less distortion during flattening, identifying curvature distribution becomes essential. Topological defects in a particle assembly on a surface in its minimum interaction-energy configuration indicate regions of concentrated curvature. In this work, an unfolding method is proposed that segments the surface using defects' location. Cutlines connecting the defects isolate lower curvature …

Data-Driven Seismic Site Classification Using Earthquake And Microtremor Horizontal-To-Vertical Spectral Ratios, Sanidhya Sharma

Graduate Studies Theses and Dissertations 2026

The prevailing seismic site classification parameter, the time-averaged shear-wave velocity in the upper 30 meters (V_S30), provides an incomplete representation of site conditions, neglecting deeper geology, impedance contrasts, and resonance phenomena. This thesis developed and validated a data-driven framework for seismic site classification based on the full spectral shape of Horizontal-to-Vertical Spectral Ratio (HVSR) curves combined with unsupervised machine learning, through two complementary research studies. Research 1 applied K-means clustering to earthquake-based HVSR (eHVSR) data from 3,186 ground motion stations across California and adjacent regions, identifying four physically distinct site clusters, characterized by low-frequency, very-low-frequency, high-frequency, and …

The Middle Space: Redefining Collaborative Directing In Adaptive American Collegiate Theatre, Tyler J. Simons

Graduate Studies Theses and Dissertations 2026

This thesis examines collaborative directing as an adaptive, relational practice that exists between rigid hierarchical authorship and fully collectivized creation. Challenging dominant binaries in directing discourse that frame leadership as either singular or egalitarian, this study argues for a “middle space” in which authority, authorship, and responsibility are continually negotiated in response to institutional structures, pedagogical contexts, and interpersonal dynamics. Directing is framed not as a fixed methodology or ideological position, but as a responsive practice shaped by context. Grounded in a practice-as-research (PaR) methodology, the thesis analyzes four productions: Rhinoceros (Theatre UCF, 2024), The Tricks of Scapin (Freedom High …

Experimental Rate Feedback Control Of A Model-Scale Hourglass-Shaped Heaving Point Absorber, James R. Halverson

Dissertations, Master's Theses and Master's Reports

Buoy geometry greatly affects a point absorber wave energy converter's dynamic response to waves. Finding the optimal buoy shape and control method remains an open research area focused on maximizing the conversion of wave kinetic energy into electricity. This work presents an experimental comparison of closed-loop energy extraction between a cylindrical and a truncated cone buoy, both with the same submerged volume, across various wave frequencies and amplitudes. To ensure a fair comparison, the optimal rate feedback gain is calculated for each buoy at each wave condition. Multiple metrics, including power output, capture width, and actuator force, are used to …

Report On A Gpr Survey Of The Copper Harbor Cemetery, Copper Harbor, Michigan, Grace Griffin

Dissertations, Master's Theses and Master's Reports

The Copper Harbor Cemetery in Grant Township, Michigan, is one of the oldest settler cemeteries in the Keweenaw, with the earliest burial dating back to 1853. The cemetery is also still used by the community today. However, consistent burial records have not been maintained throughout the cemetery's entire history, leading to some doubt about which areas of the cemetery can be opened for new burials and where excavation should be avoided. For this reason, Grant Township commissioned a ground penetrating radar (GPR) survey of the cemetery, primarily to locate anomalies indicating possible unmarked graves and possible buried headstones. The survey …

Numerical And Experimental Evaluation Of A Simple, Low-Energy Lunar Volatile Separation Technology, Eleanor L. Zimmermann

Dissertations, Master's Theses and Master's Reports

In-situ resource utilization (ISRU) is the practice of finding, extracting, and using the local resources found on extraterrestrial bodies, such as the Moon and Mars. ISRU enables in-situ production of mission consumables—such as rocket fuel and potable water—which will be critical for establishing a sustainable human presence on the Moon, a goal NASA intends to accomplish by 2028 with the Artemis missions. The separation and liquefaction of locally extracted volatiles—such as water, CO₂, and Methane—is an essential component in lunar surface sustainability, but there are very few technologies being developed for this purpose. This report introduces the Radiative …

Nondestructive Evaluation Of Additively Manufactured Parts Using Resonant Inspection And Frequency Domain-Based Correlation Criteria, Gita Deonarain

Dissertations, Master's Theses and Master's Reports

Additive manufacturing (AM) enables the production of highly customized and geometrically complex components; however, these parts remain susceptible to a wide range of defect types and severities. The combination of complex geometries and distributed defects presents a significant challenge for post-process nondestructive evaluation (NDE). Conventional inspection techniques, such as computed tomography and ultrasonic testing, are often limited by geometry, material, accessibility, and cost, while in situ monitoring is not yet sufficiently mature to replace post-process inspection.

This dissertation establishes the Frequency Domain Assurance Criterion (FDAC) as a quantitative, vibration-based framework for defect detection in AM components. FDAC captures spatial–spectral correlations …

The Excess Path Length Distribution: A Stochastic Model For Sample-Based Path Planners, Chaz B. Cornwall

Dissertations, Master's Theses and Master's Reports

Through random sampling, sample-based path planners enable autonomous agents to quickly find paths without human intervention. However, due to the paths' randomness, sample-based path planners currently require additional verification, partially nullifying agents' ability to act autonomously. I set out to characterize this uncertainty so humans know what to expect from these path planners and know how to alter the path planner to desired specifications. To ensure the results are theoretical as well as practical, I first create a stochastic model of path length uncertainty using the trade-off between sampling time and optimality. By leveraging this model, my proposed algorithm reduces …

Modeling Determinants Of Significant Noncompliance In The U.S. Mining Sector: A Fixed Effects Logistic Regression Approach, Eli Johnson

Dissertations, Master's Theses and Master's Reports

This study examines environmental compliance behavior among mining facilities regulated under the U.S. Clean Water Act (CWA). Using a national quarterly panel of National Pollutant Discharge Elimination System (NPDES)-permitted mining facilities, the analysis evaluates whether local socioeconomic and demographic indicators are associated with the likelihood that a facility enters significant noncompliance (SNC) status. Facility compliance histories are compiled from the U.S. Environmental Protection Agency’s Enforcement and Compliance History Online (ECHO) database and is merged with county- and state-level socioeconomic indicators and election data. A fixed-effects logistic regression model is used to account for time-invariant facility heterogeneity. The results suggest that …

Microgravity-Induced Alterations In Left Atrial Hemodynamics And Thrombogenic Risk: Insights From Healthy And Atrial Fibrillation Models, Grace M. Hoeppner

Dissertations, Master's Theses and Master's Reports

Background: Microgravity exposure alters cardiovascular loading, yet its impact on left atrial flow dynamics and thrombotic risk remains poorly understood. This study investigates how spaceflight-relevant microgravity-induced changes in cardiac outflow affect left atrial hemodynamics in healthy individuals and patients with atrial fibrillation.

Methods: Patient-specific left atrial models were generated for three healthy individuals and three AF patients. Computational fluid dynamics (CFD) simulations were performed using each patient’s baseline mitral outflow waveform and two modified waveforms representing short- and long-duration post-flight cardiac loading changes derived from echocardiographic observations. Hemodynamic metrics included left atrial velocity, time averaged wall shear stress, oscillatory shear …

Shm For Incipient Buckling Detection In Overloaded Structures Using Nonlinear System Identification Algorithms On Redundant Data Sets, Padmanabh Shridhar Desai

Dissertations, Master's Theses and Master's Reports

Structural health monitoring (SHM) detects and characterizes damage to predict failure, but failures such as buckling, which are not predicated on traditional damage modalities, are harder to detect. Direct load measurements are costly and difficult to implement (especially for dead loads) as they require copious numbers of sensors, which must be installed before loading is present. Vibration-based detection is a good alternative because it can infer global structural characteristics with relatively few sensors. This dissertation presents an SHM approach for detecting incipient buckling in structures under excessive loads based on non-linear models fit from measurements of small lateral vibrations due …

Development And Calibration Of A 2-D Diesel Oxidation Catalyst Filter (Docf) Model With Spatially Varying Washcoats Using Spacims And Engine Loading Data, Thomas K. Price

Dissertations, Master's Theses and Master's Reports

Diesel engine exhaust contains regulated species, including carbon monoxide, hydrocarbons, nitrogen oxides, and particulate matter (PM). Meeting increasingly stringent emission standards typically requires multiple aftertreatment components, motivating the development of multifunctional devices that reduce system size, cost, and catalyst usage. Computational models are essential for guiding this design process; however, existing models primarily focus on single-function devices and rarely capture the behavior of multifunctional systems with multiple catalyst washcoats. This work presents a physics-based model of a wall-flow diesel oxidation catalyst filter (DOCF), a multifunctional device that integrates the roles of a diesel oxidation catalyst and a diesel particulate filter …

On The Vibrational Dynamics Of Wind Turbine Blades: The Oscillatory Response To Gust Pulses, And The Physical Mechanisms Behind Them, North A. Yates

Dissertations, Master's Theses and Master's Reports

An easily noticed trend in the utility-scale wind turbine industry is that the size of the machines has continued to increase over time. While this may have benefits in terms of increasing the power generation for a single turbine, a major drawback is the rate with which the weight of the turbine blades grow. To ensure these larger machines can be utilized, efforts are being put forth to create lighter blades. This may fix the weight issue, but brings on a new one; these lighter blades can also be more flexible than previously studied ones. It is, therefore, vitally important …

Digital Technology And Women’S Health In Nigeria: A Feminist Sts Walkthrough Analysis Of Mdoc Digital Health, Edith Michael Ogbodo

Dissertations, Master's Theses and Master's Reports

This thesis critically examines how a Nigerian digital health platform, mDoc, represents and constructs women’s health. Drawing on Feminist Science and Technology Studies (STS) and Light et al.’s (2018) walkthrough method, the study interrogates the values, assumptions, and power relations embedded in mDoc’s design, language, and governance structures. The analysis reveals that mDoc, despite positioning itself as an equitable solution to Nigeria’s health crisis, reproduces and depoliticizes the structural inequalities it claims to address. Through its neoliberal emphasis on self-care, the individualization of structurally produced suffering, and the datafication of women’s bodies, the platform encodes gendered, colonial, and class-based assumptions …

Computational And Ai Frameworks For Identifying Key Regulatory Genes And Their Target Genes In Plants And Humans, Md Khairul Islam

Dissertations, Master's Theses and Master's Reports

This dissertation presents computational and AI-driven frameworks for identifying key regulatory genes and their downstream targets across plant and human biological systems. Three studies address distinct challenges in genomic regulation using advanced machine learning and bioinformatics approaches.

The first study introduces DyGAF (Dynamic Gene Attention Focus), a dual-attention transformer framework that identifies and ranks disease-relevant biomarker genes by simultaneously modeling independent molecular responses and interdependent regulatory network behavior. Two attention models provide complementary perspectives on gene importance and are fused through a novel combination metric. Applied to COVID-19 nasopharyngeal swab profiles, the attention-weighted representations achieved 94.23% classification accuracy, high sensitivity, …

Path-Conservative Numerical Methods For A Variable-Radius One-Dimensional Arterial-Flow Model, Daniel Henderson

Dissertations, Master's Theses and Master's Reports

This report studies a one-dimensional arterial-flow model with a variable reference radius, the two-component state $U=(a,q)^{\mathsf T}$, and diagnostic pressure. The geometry-dependent momentum term is interpreted with a declared Dal Maso--LeFloch--Murat path along a straight line. A path-conservative finite-volume method (FVM) and a complete modal discontinuous Galerkin (DG) method use the three-stage, third-order strong-stability-preserving Runge--Kutta (SSPRK) scheme SSPRK(3,3), residual-subtracted rest preservation, overintegrated nonlinear volume terms, and mean-preserving area positivity scaling. Code verification uses manufactured solutions with separate dimensionless area and flow errors, temporal refinement, represented-rest fixed-point checks, independent governing-expression evaluations, and an independently assembled DG residual. The smooth degree-three (P3) …

Machine Learning And Multi-Scale Optimization For Control And Energy Management In Connected And Automated Vehicle Propulsion Systems, Joshua D. Orlando

Dissertations, Master's Theses and Master's Reports

This dissertation presents a multi-scale optimization framework leveraging machine learning (ML) to enhance energy efficiency in connected and automated vehicle (CAV) propulsion systems. As transportation transitions toward hybridization and automation, the integration of vehicle-to-everything (V2X) connectivity and advanced control algorithms offers unprecedented opportunities for energy reduction. This research addresses three critical scales of vehicle energy management: multiple vehicle-level coordination, component-level powertrain dynamics, and real-time vehicle parameter estimation.

First, the research investigates the energy consumption characteristics of heterogeneous propulsion systems—ranging from internal combustion engines to battery electric vehicles across light- and heavy-duty sectors—on arterial roadways. Utilizing Particle Swarm Optimization (PSO) and …

Study Of Bearing Capacity Testing And Soil Preparation Techniques In Lunar Highlands Simulant At Field Scale, Christi A. Lecaptain

Dissertations, Master's Theses and Master's Reports

Humanity seeks to return to the surface of the Moon with the advent of the Artemis missions. These endeavors plan to be the beginning of a new era as NASA and other space organizations seek to establish a lunar base. Ahead of any astronauts or mining infrastructure, the physical groundwork will need to be laid to support the arrival of rockets, boots, and rover wheels. As surfaces are prepared, they will need to be tested and verified to ensure the stability of any structures placed on top. Understanding the bearing capacity is vital to soil quality testing. A standard terrestrial …

Design And Experimental Evaluation Of A Custom Vision-Guided Approach To 2d Part Localization For Industrial Robots, Faisal Ali

Dissertations, Master's Theses and Master's Reports

Vision-guided robots offer a clear advantage over teach-pendant programming for battery handling, where modern packs hold thousands of cells and teaching each position by hand does not scale. Commercial vision systems address this need, but their calibration, detection, and coordinate-conversion stages are closed to the user, making it hard to incorporate newer learning-based methods. This work presents a modular, custom-built vision-guided system using an Orbbec Gemini 435Le eye-in-hand camera, an NVIDIA Jetson Orin Nano, an Allen-Bradley Micro850 PLC, and a FANUC LR Mate 200iC, communicating over Modbus TCP and EtherNet/IP. A per-hole classification model resolves each known hole into a …

Physicochemical Characterization Of Small Extracellular Vesicles: Effects Of Immobilization, Isolation, And Disease State, Bianca M. Mercado Velez

Dissertations, Master's Theses and Master's Reports

Cancer treatments and survival outcomes have improved significantly in the last couple of decades, with survival rates increasing in the U.S. Despite improvements in treatment outcomes, early detection and treatment are crucial for improving cancer prognosis and survival rates. The standard cancer diagnostic procedure of tissue biopsy is highly invasive, leading to the further spread of cancer in some cases. Alternatively, the extraction of biofluids from cancer patients, also called a liquid biopsy, is increasingly popular because it is less invasive and more representative of the tumor microenvironment, which contains cancer cells, tumor genetic material, and extracellular vesicles, including small …

Antenna-Based Sensors For Dielectric Characterization Of Materials, Hilary Scott Nkimbeng Cho

Dissertations, Master's Theses and Master's Reports

This research introduces antenna-based sensors for dielectric characterization aimed at overcoming the limitations of conventional microwave sensors. Although traditional microwave sensors are widely used for their noncontact operation, high sensitivity, and ability to penetrate various materials, they often face challenges such as large size and high-power consumption. To address these issues, antenna-based sensors are explored for their compactness, ease of fabrication, and flexible design adaptability across diverse sensing applications. An in-depth analysis of multiple antenna sensor configurations is conducted, followed by the design and development of high-performance sensing structures. A saw-tooth slot antenna sensor is developed for highly sensitive liquid …