Digital Commons Network^™

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 …

Novel Chiral Interstellar Molecules: Quantum Anharmonic Ir And Vcd Predictions, Meredith Paik

Dissertations, Master's Theses and Master's Reports

The 2016 discovery of the chiral molecule propylene oxide (C₃H₆O) in the interstellar medium (ISM) has opened new avenues into explaining the origin of biomolecular homochirality on Earth. Thus, studies of chiral molecules in the ISM may be able to reveal more about the mechanism behind homochirality. However, while the search for chiral molecules in space has become an active field of study, astrochemical researchers have yet to detect other chiral molecules in the ISM. For this purpose, numerous characteristics for detectability have been outlined that may facilitate the discovery of other interstellar chiral molecules. With …

Applied Forest Restoration And Conservation In Michigan: Advancing American Beech Restoration And Documenting A Historical Insect Collection, Thomas E. Panella

Dissertations, Master's Theses and Master's Reports

Forest restoration and conservation require both practical management approaches and the preservation of biological resources that support future research. This dissertation presents applied research conducted in Michigan that advances American beech (Fagus grandifolia) restoration in response to beech bark disease (BBD) while documenting an important historical entomological resource. Chapters 1–3 focus on overcoming practical barriers to American beech restoration. Restoration protocols were developed and refined for identifying BBD-resistant trees, graft propagation, rootstock collection, container production, and the field establishment of grafted BBD-resistant trees. A greenhouse experiment evaluated the influence of growing media and fertilization on container stock quality, …

Targeted And Screening Based Approaches To Analyze Drm Transcriptional Repressor Complex Activity In Caenorhabditis Elegans, Emily Washeleski

Dissertations, Master's Theses and Master's Reports

The molecular machinery that control the eukaryotic cell cycle, specifically the processes that mediate the switch between cellular division or quiescence, are essential for cellular and organismal viability. However, how the same machinery integrates with developmental or differentiation programs is less well understood. In Caenorhabditis elegans, the 8-subunit DRM complex (for Dp, Rb and MuvB), whose subunits belong to the Synthetic Mulitivulva (SynMuv) B class genes, is a central regulator of the cell cycle but also prevents inappropriate cell fate specification. The conserved mammalian DREAM complex (for Dp, Rb, E2F, And MuvB) is best known as a transcriptional repressor …

First-Principles Investigation Of Quasi-One-Dimensional Van Der Waals Magnets For Advancing Low-Dimensional Spintronics, Alyssa Horne

Dissertations, Master's Theses and Master's Reports

Van der Waals (vdW) magnets have been of great interest for advancing low- dimensional spintronics. A notable example is the quasi-one-dimensional (Q1D) vdW CrSbSe₃, as it is composed of individual one-dimensional units that are held together by the vdW forces. Finding other Q1D vdW magnets that exhibit non-metallic behavior together with long range ferromagnetic ordering is critical in developing next generation spintronics. Here in, using first-principles density functional theory (DFT), we investigate the compositional effects on electronic and magnetic behavior of Cr_1–xMn_xSbSe₃ (x = 0, 0.5, 1). When 50% of Cr is replaced …

Using Automotive Lidar To Reduce The Energy Consumption Of An Ego Autonomous Vehicle, Logan P. Schexnaydre

Dissertations, Master's Theses and Master's Reports

There is significant potential to reduce the energy consumption of the transportation sector through autonomous vehicles. Prior work on autonomous vehicle energy efficiency focuses on the whole system or the control subsystem. Yet, the sensing and processing components, which have direct and indirect effects on net energy use, are less explored. This dissertation fills this gap by modeling and evaluating these effects for lidar sensors, which provide high-resolution spatial data at the cost of high power and processing demands. I apply lidar to the energy-saving tasks of automated vehicle following and road surface profiling. For automated vehicle following, I model …

Analytical And Data-Driven Modeling And Control Of Nonlinear Point Absorber Wave Energy Converters With Application To Cone–Cone Buoy Geometries, Houssein Yassin

Dissertations, Master's Theses and Master's Reports

This dissertation develops analytical modeling, numerical simulation, experimental validation, and data driven control methods for nonlinear point absorber wave energy converters, with particular emphasis on cone--cone buoy geometries. Geometry dependent nonlinear force models are first derived using pressure field and displaced volume formulations. These models show how buoy geometry produces nonlinear Froude--Krylov and restoring forces, including the dominant cubic behavior of cone--cone geometries.

The derived models are incorporated into a feedback linearization framework that compensates selected nonlinear dynamics while retaining the incident wave terms. An analytical optimal control formulation is also developed to maximize harvested energy in nonlinear, nonautonomous systems …

Rapid Austenite Restoration Through Non-Partitioning Transformation In Medium-Mn Steel, Rebekah A. Smith

Dissertations, Master's Theses and Master's Reports

Steel microstructures that contain retained austenite exhibit unique mechanical flow behavior which renders them applicable to high-strength forming, and energy absorbing applications. Austenite stability is predominantly controlled through substitutional alloy enrichment, and during deformation, meta-stable austenite transforms to martensite which induces dramatic work hardening that may enhance mechanical properties. After deformation, these steels have greater yield strength but limited remaining ductility. Restoration of austenite through rapid thermal treatments, after it is expended through deformation, can enable retained austenite to be leveraged for additional deformation. In the present work, a rapid austenite restoration heat treatment following deformation-induced martensite transformation is presented …

Enhancing Coastal Vulnerability Assessments And Policy Impacts On Socioeconomic And Environmental Equity In Michigan's Great Lakes Communities, Esther N. Acheampong

Dissertations, Master's Theses and Master's Reports

Accelerating shoreline erosion, fluctuating lake levels, and climate-induced hazards are transforming the Great Lakes’ freshwater coasts, exposing the limitations of static and inequitable management frameworks. This dissertation investigates how Michigan’s coastal governance systems produce and manage vulnerability along the Lake Michigan shoreline by integrating geospatial modeling, institutional policy analysis, and environmental justice theory. It argues that both physical processes and institutional designs co-determine patterns of exposure, protection, and equity. The research begins by developing a refined Coastal Vulnerability Index (CVI) tailored for lacustrine environments, applying it to Muskegon County to assess how shoreline change, armoring, and seasonality influence localized risk. …

Are Iowa Pk-12 Schools Prepared For A School Shooting? A Needs Assessment Of Iowa Superintendents, Kurt Mj Devore

Dissertations and Theses @ UNI

As school shootings remain a persistent threat to PK-12 education, this quantitative survey study examines the preparedness levels and beliefs of 75 out of 277 Iowa superintendents regarding active shooter events. In the wake of the 2024 tragedy in Perry, Iowa, results indicate a near-universal recognition of risk (97.3%), prompting a shift toward "muscle memory" training and the adoption of the Standard Response Protocol (SRP) to ensure a common language during a crisis. The data reveals a significant move away from high-intensity simulations in favor of trauma-informed tabletop exercises, alongside a definitive rejection of arming educators (0%) due to insurance …

The Shared Superintendent In Iowa: Benefits, Challenges, And Lessons Learned Over The Last Thirty Years, Amanda Schmidt

Dissertations and Theses @ UNI

This study examined the benefits, challenges, and leadership qualities associated with the shared superintendent model, and compared them with lessons learned over the last thirty years. Understanding how this model impacts dynamics within schools and the community is crucial to identifying strategies that support effective governance and enhance educational outcomes for all involved. A qualitative, phenomenological study approach was used to research the role of the shared superintendent in rural Iowa. Participants were those who served as a shared superintendent between a minimum of two school districts within the state of Iowa and have held this position for at least …

Multi-Level Energy Optimization For Connected And Automated Vehicles: From Cooperative Multi-Vehicle Control To Individual Powertrain Management, Pruthwiraj Santhosh

Dissertations, Master's Theses and Master's Reports

The transportation sector currently accounts for nearly 30% of global energy consumption, necessitating urgent advancements in vehicle efficiency to meet Net Zero targets. Leveraging connectivity and automation, this dissertation proposes and validates methodologies to reduce the energy consumption of light-duty vehicles at both fleet and individual levels.

First, a validation framework is developed to bridge the “simulation-to-real world” gap in Cooperative Automated Vehicle (CAV) research. Moving beyond virtual simulations, the study establishes a methodology for physically validating centralized control architectures via a custom Cellular V2X network. By synchronizing vehicle-powertrain models with physical test vehicles, the framework successfully orchestrates complex arterial …

On The Surface: The Mural Of Shireen Abu Akleh As Space For Encounter, Saja Abd El Hai

Dissertations and Theses @ UNI

This thesis examines a mural of Palestinian journalist Shireen Abu Akleh in the city of Baqa al-Gharbiya as a site of political encounter. Rather than approaching the mural solely as a commemorative image, the study analyzes how it generated a series of interactions through acts of creation, defacement, restoration, performance, and digital circulation. Drawing on scholarship in visual culture, graffiti studies, and political theory, I argue that the mural operates as a gendered space of political encounter through which grief, resistance, and national identity are negotiated in public space. Methodologically, the project combines visual and contextual analysis with rhetorical criticism, …

Exploring Governance And Government Policies Of Preparedness And Response To Flooding In Juneau, Alaska, Derreck Asiamah

Dissertations and Theses @ UNI

Flooding poses an escalating threat to human well-being, economic stability, and environmental resilience in climate-sensitive regions such as Juneau, Alaska, where the retreat of the Mendenhall Glacier has produced an actively expanding ice-dammed lake, Suicide Basin, capable of triggering an annual Glacial Lake Outburst Flood (GLOF). This thesis explores the governance and government policies shaping flood preparedness and response in Juneau, Alaska, with particular attention to GLOF risk and the August 2024 GLOF, one of the most destructive flood events in the city's history. Grounded in adaptive governance theory and political ecology, the study offers a multidimensional perspective on institutional …

Stem Identities Of Iowa State University's Biological And Biomanufacturing Systems Technology Students, Levi Nettleton

Dissertations and Theses @ UNI

STEM identity plays a crucial role in students' pursuit and persistence into the STEM field. Iowa State University's Biological and Biomanufacturing Systems Technology (BBST) undergraduate program, developed in alignment with the goals of Chemurgy 2.0, prepares students for careers in the growing STEM workforce. The purpose of this study is to examine how participation in the Biological and Biomanufacturing Systems Technology program influences undergraduate students' STEM identity and how students within the program perceive themselves within the scope of STEM. Specifically, the study investigates students' perceptions of their STEM identity across the four components of STEM identity: recognition, performance and …