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Advanced Ysz/Si(B)Cn And Bnnt/Si(B)Cn Ceramics Matrix Composites For Extreme Environments In Hydrogen Combustion, Yiting Wang

Graduate Studies Theses and Dissertations 2026

The growing demand for carbon-neutral energy conversion has accelerated the development of hydrogen-fueled gas turbine systems, which operate at significantly higher temperatures and more chemically aggressive environments than conventional natural gas turbines. To meet these stringent requirements, ceramic matrix composite (CMC) materials consisting of yttria-stabilized zirconia (YSZ) fiber reinforced Si(B)CN ceramic matrix were developed. To further enhance in-plane heat dissipation, thermal stability, thermal shock resistance, and thermal cycling performance, a Si(B)CN/Boron Nitride Nanotubes (BNNT) nanocomposite coating was incorporated onto the YSZ/Si(B)CN composites. Microstructural characterization confirmed the formation of a continuous Si(B)CN ceramic matrix reinforced with uniformly distributed BNNTs. The resulting …

Voltage Stability Enhancement Of Large Load Interconnections Using Syncronous Condensers, Muhammad Ibrahim Abbas

Graduate Studies Theses and Dissertations 2026

The rapid integration of hyperscale data centers as large, concentrated loads presents a growing voltage stability challenge in grids weakened by synchronous generator retirement and increasing inverter-based resource penetration. This work proposes a Jacobian-based sensitivity framework for systematically identifying voltage-critical buses and optimally siting synchronous condensers as voltage support resources. A voltage-weighted sensitivity index, extracted from the full Jacobian inverse, is introduced to combine network-wide reactive coupling strength with observed voltage drops into a single deployable placement criterion. Validation on IEEE 14-bus and 30-bus test systems under multiple loading scenarios demonstrates that the proposed criterion consistently identifies the correct placement …

Examining Patient Safety Culture Trends In U.S. Healthcare Through A Multi-Year Analysis, Hassan Alabdullah

Graduate Studies Theses and Dissertations 2026

Patient Safety Culture (PSC) is recognized as a cornerstone of healthcare quality and a key determinant of patient outcomes. Despite the Institute of Medicine’s early calls to establish safety-oriented systems, evidence on the long-term stability of PSC in U.S. hospitals has remained limited. This dissertation addresses this gap through a multi-year evaluation of PSC using the Hospital Survey on Patient Safety Culture (HSOPSC v1.0) and advanced statistical methods. Drawing on one of the largest national datasets—comprising over 993,000 healthcare providers from 1,601 U.S. hospitals across three survey cycles (2013–2020)—the study employed a longitudinal repeated cross-sectional design. Analyses combined descriptive statistics, …

First-Principles Insights Into Electronic And Magnetic Structure At Hybrid Interfaces And Low-Dimensional Materials And Reaction On Surfaces, Bushra Ashraf

Graduate Studies Theses and Dissertations 2026

Low-dimensional materials and transition metal surfaces/interfaces provide complementary platforms for understanding how dimensionality, symmetry, spin–orbit coupling (SOC), and interfacial charge transfer/hybridization jointly control electronic structure, emergent magnetism, and surface reactivity. Using first-principles modeling with experimental comparisons, this work aims to establish interfacial structure–property relationships across low-dimensional systems.

Strained Pd adlayers on 2H-MoS₂(0001) provide a controlled platform to separate strain-driven exchange from interface-induced quenching in an itinerant d-electron metal. Although expansive strain promotes magnetism in free-standing Pd, strong Pd–MoS₂ hybridization and charge transfer suppress the monolayer moment and leave a narrow thickness window where magnetism re-emerges in …

An Algorithmic Framework For Polyhedral Gravity Modeling And Trajectory Propagation Near Small Bodies, Micah S. Boudreau

Graduate Studies Theses and Dissertations 2026

Near-Earth asteroids (NEAs) and other irregular celestial bodies have become increasingly significant targets for scientific investigation and space mission development due to their relevance to resource utilization, origins-of-life studies, planetary defense, and understanding of early solar system formation. As launch costs continue to decline, missions such as NASA’s NEAR Shoemaker, OSIRIS-REx and JAXA’s Hayabusa series demonstrate the expanding feasibility of detailed small body exploration. Despite this growing interest, most standard astrodynamics tools are not designed to model the complex, highly irregular gravitational fields that are a signature of small bodies. Such limitations pose challenges for trajectory design, navigation, and control …

Enhanced Atomization And Combustion In Subsonic Ljic Systems Using Ultrasonically Driven Solid Obstructions, Daniel Sebastian Cruz

Graduate Studies Theses and Dissertations 2026

The liquid fueling methods used in aircraft propulsion have undergone extensive optimization, with Liquid Jets in Crossflow (LJIC) emerging as a simple yet effective injection scheme. LJIC enables sufficient fuel mass flow rates and penetration for high-speed operation, however fuel trajectory and droplet size remain highly sensitive to crossflow conditions. As a result, wide flight envelopes introduce variability in atomization, leading to unsteady combustion performance. Recent work has incorporated a pintile, a solid obstruction placed in the path of the fuel jet, to redistribute momentum and reduce trajectory variability across varying flow conditions. While this approach improves trajectory uniformity, it …

Centered A Story Of Family And Compassion In The Face Of Parkinson's Disease, Savannah Hill

Graduate Studies Theses and Dissertations 2026

Centered is a three-dimensional (3D) animated short film that explores the topic of parental illness and how families must respond with compassion and adaptability when loved ones face mental or physical challenges. The story is inspired by the director’s own experience with her father’s diagnosis of Parkinson’s Disease when she was in high school. The main characters, a father and daughter, must navigate the father’s changing needs after his diagnosis by prioritizing their connection and adapting to his new physical challenges. In the film, they do this through the creation of pottery. The imperfect, handmade design style of the film …

Numerical Simulation Of Micro-Cutting Processes For The Estimation Of Material Fracture Toughness, Juan J. Lainez

Graduate Studies Theses and Dissertations 2026

Accurate determination of plane-strain fracture toughness is essential for structural integrity assessments of engineering components, yet conventional ASTM standardized testing methods require large, notched specimens that are impractical in many industrial and research contexts. This thesis presents a finite element method-based approach for estimating the mode I plane-strain fracture toughness of engineering materials from orthogonal micro-cutting simulations if the continuum damage mechanics-based fracture locus is calibrated. This method will eliminate the need for pre-cracked specimens while maintaining physically grounded fracture mechanics principles. The methodology applies to the Atkins energy-based cutting force model, in which the depth-independent intercept of the specific …

Sensitivity Analysis Of Tuned And Intentionally Mistuned Blisks To Random Mistuning, Tate A. Myers

Graduate Studies Theses and Dissertations 2026

The vibrational behavior of bladed disks, or blisks, is highly sensitive to variations in its cyclic symmetry due to variations in mass, stiffness, damping, or a combination of these factors. These inconsistencies can arise from manufacturing tolerance inconsistencies, operational wear, impacts during usage, and intentional mistuning. This thesis develops an analysis of the sensitivity of both tuned and intentionally mistuned blisks to random mistuning in their structural properties. Sobol sampling combined with state-space eigen-analysis is utilized to develop a set of randomly mistuned systems. Modal Assurance Criterion is used to track the mode shapes of each randomly mistuned system back …

Adaptability And Applications Of Advanced Laser Absorption Diagnostics In High-Pressure Shock Tube Environments, Lucas R. Pitts

Graduate Studies Theses and Dissertations 2026

Theoretical application and physical implementation of various laser absorption spectroscopy (LAS) diagnostics are examined within a high-pressure shock tube facility. Research focuses on the rationale behind the specific optical alignment layouts used across three distinct experimental campaigns, detailing the methodology required to maintain signal integrity in varied reacting flow environments. The first research campaign addresses the pyrolysis of hydroxyl terminated polybutadiene (HTPB) solid propellant binders for solid fuel ramjet (SFRJ) applications by measuring the species time histories of alkenes and aromatics. Alignment configurations prioritized beam stability and signal strength for the decoupling of overlapping absorption features to ensure measurements accurately …

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. …

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 …

Machine Learning Acceleration Of Micro-Credentialing, Knowledge Gap Remediation, And Micro-Recruiting Of Stem Assessments: From Learner Data To Hardware, Paul Amoruso

Graduate Studies Theses and Dissertations 2026

The growing demand for a skilled STEM workforce calls for adaptive, data-driven education that personalizes learning while aligning competencies with industry needs. This work introduces a multi-layered framework that integrates artificial intelligence (AI), data mining and hardware-aware optimization to support this goal. At its core, the AchieveUp system applies generative AI-assisted skill tagging to digitized assessments, enabling multi-semester tracking of student progress. Analysis across 14 semesters shows that underperforming students were found to benefit most from attending score clarification sessions, a relationship validated by an R² value of 0.83, indicating strong predictive validity between attendance and skill acquisition. To remediate …

Essays On Network Resilience: Enhancing Network Resilience Through Network Governance Structure, Process, Environment, And Leadership, Hanvit Kim

Graduate Studies Theses and Dissertations 2026

As disasters become more complex, their impacts often cascade across interdependent systems, creating failures that extend beyond any single organization or sector. Because such crises cut across organizational and sectoral boundaries, effective response depends not only on the capacity of individual organizations but also on the resilience of interorganizational networks. Yet despite the growing importance of networked coordination in disaster response, the concept of network resilience remains underdeveloped in the literature, with limited consensus on its definition, measurement, and determinants. This dissertation addresses that gap by systematically examining what network resilience is, how it can be conceptualized and assessed, and …

Investigation Of Bulk And Periodically Stacked X(2) And X(3) Materials Using Mid-Infrared Femtosecond Pulses, Woraprach Kusolthossakul

Graduate Studies Theses and Dissertations 2026

Mid-infrared (MIR) spectral region represents a vital part of the electromagnetic spectrum, offering applications in spectroscopy, biomedicine, and remote sensing. However, there are no direct broadband MIR laser sources. Nonlinear frequency conversion techniques using second-order nonlinear materials, such as optical parametric oscillator (OPO) and intra-pulse difference frequency generator (IDFG), are promising methods for generating a broadband MIR spectrum. To achieve an efficient conversion, the phase matching condition between the interacting waves of the nonlinear process must be satisfied. Quasi-phase matching (QPM) is a special technique that enables efficient nonlinear processes in materials that cannot be conventionally phase matched using birefringence. …

Reliability Of Staged Maximal Aerobic Capacity Protocol Using A Combined Upper- And Lower-Body Air-Braked Ergometer, Jack J. Livingston

Graduate Studies Theses and Dissertations 2026

Maximal oxygen uptake (VO₂max) is widely recognized as the preeminent measure of aerobic capacity and is typically assessed using graded exercise testing (GXT). This study examined the test–retest reliability of VO₂peak and associated physiological responses during a staged GXT performed on a combined upper- and lower-body air-braked ergometer. Fifteen recreationally active adults (9 males, 6 females; age: 26.9 ± 7.2 years; body mass: 75.1 ± 11.0 kg) completed one familiarization session and two trials separated by ≥72 hours. Participants performed a staged GXT (40 RPM start, +3 RPM every 3 min to exhaustion) on a combined upper- and lower-body air-braked …

Computational Regolith Mechanics And Instrumentation Development For Lunar Exploration And Resource Utilization, Jared M. Long-Fox

Graduate Studies Theses and Dissertations 2026

Sustained exploration of the Moon requires quantitative understanding of lunar regolith properties to support scientific investigation, in situ resource utilization, excavation, and infrastructure development. This dissertation examines the mechanical interaction between robotic excavation systems and lunar regolith, emphasizing how regolith behavior both enables and constrains exploration-focused and exploration-enabled science. Computational excavation models were compared to laboratory data to evaluate prediction of excavation forces and to develop metrics of excavation efficiency. Laboratory experiments using high-fidelity lunar regolith simulants were conducted to characterize pressure-sinkage behavior, shear strength, and angle of repose across a range of material states. Common analytical excavation and terramechanics …

Exploring The Temporal Dynamics Of Gaming-The-System And Self-Regulated Learning Behaviors Within A Game-Based Learning Environment, Cameron E. Marano

Graduate Studies Theses and Dissertations 2026

Consistently monitoring and regulating cognitive and metacognitive skills during learning is difficult. As a result, game-based learning environments (GBLEs) have been designed to provide richer learning experiences. They foster self-regulated learning (SRL) skills and offer a way to study learners' interactions within complex environments. Although SRL in GBLEs has been widely studied, large gaps remain. For example, it is unclear how improper or maladaptive regulation in GBLEs signals gaming-the-system, in which learners manipulate features to avoid authentic learning. This phenomenon is widely studied in intelligent tutoring systems (ITSs). Limited research has examined how and when both gaming-the-system and SRL behaviors …

The Revelations, Lily Mckenna

Graduate Studies Theses and Dissertations 2026

The Revelations is a self-actualization in the form of a poetry collection. The speaker’s realization that reality is relative arrives through a Title IX case against an abusive boyfriend and former bandmate. Poems such as “Complainant / Respondent” use rigid legal structures to investigate the fluidity of truth and perception and how they can be manipulated. With her band on hiatus and the case propelling her into a new world, the speaker starts running DIY shows alongside a cast of characters with a shared love of music. She interrogates their realities in the character studies “On The Relative Reality Of…,” …

Temporal Patterns Of Storm Surges: Event-Identification, Clustering, And Count Modeling, Ariadna Martin Oliva

Graduate Studies Theses and Dissertations 2026

Coastal regions face compounding risks when extreme events strike in rapid succession, yet most statistical frameworks treat such events as independent, a simplification that can critically underestimate hazard. This thesis addresses that gap through three interconnected contributions focused on the temporal clustering of storm surges at the global scale. A new automated method is developed to extract independent storm surge events from continuous tide gauge records. By leveraging event correlations and a soft-margin approach that accounts for local variability, the method identifies characteristic event durations across 1,485 global tide gauge stations, revealing the influence of both local site conditions and …

Structural Design And Development Of Deployable Propeller Blade, Annan Mashin

Graduate Studies Theses and Dissertations 2026

Aerospace systems frequently face competing requirements between compact packaging and high aerodynamic performance. Large propellers improve efficiency and thrust generation, yet launch constraints and confined storage volumes limit their maximum span. Conventional deployable solutions rely on hinges, locking mechanisms, and external actuation, increasing mechanical complexity and reducing reliability. This dissertation investigates an alternative approach in which elastic instabilities in thin composite shells are deliberately harnessed to enable rapid, mechanism- free deployment of aerodynamic structures. This work harnesses propagating instability in open- section thin-walled airfoil geometries to enable reversible transformation between compact stowed and stiff deployed configurations. By tailoring structural architecture, …

Deceptive Design And Disability: How Dark Patterns Affect Users With Visual Impairments, Konstantin Metz

Graduate Studies Theses and Dissertations 2026

Dark patterns are deceptive interface designs that steer users toward unintended actions, often at financial or privacy cost. This thesis examines how those that are vision impaired are at greater risk of these dark patterns given their visual acuity deficit. We conducted semi structured interviews with nine participants across common contexts including e-commerce checkout, subscription and cancellation flows, software download pages, and mobile permission prompts. The data show recurring exposure to dark patterns such as hidden or de-emphasized fees, pre-selected add-ons, deceptive advertising and fake download buttons along with unequal consent paths, repeated permission nagging, and cancellation friction. Participants reported …

Chemical Kinetic Experiments Of Monomethyl Hydrazine Combustion Products At High Pressures And High Temperatures In A Shock Tube, Cooper Q. Mills

Graduate Studies Theses and Dissertations 2026

This study presents experimental shock tube laser absorption spectroscopy data to validate high-pressure and high-temperature chemical kinetic mechanisms for mixtures of H₂/air, NH₃/air, and H₂/CO/NO₂/air diluted in argon (95-98%) at high pressures (5, 10, 25 bar) and high temperatures (1000 to 2150 K). The mixtures were at equivalence ratios of 0.5, 1.0, and 1.5 to cover the range of possible conditions experienced throughout practical combustors. Laser absorption spectroscopy data was measured for NH₃, H₂O, CO, and NO using a novel multi-species setup. Chemical kinetic mechanisms contain the fundamental …

Cfd Investigation Of Heat Transfer Enhancement In Pipes Using Gyroid Tpms Structures For Industrial Steam Generation, Alejandro Moreno Escribano

Graduate Studies Theses and Dissertations 2026

Industrial heating processes account for nearly 28\% of global CO2 emissions, and fossil fueled boilers predominate in high temperature applications. Industrial electrification can be an effective solution when combined with renewable energy sources. Increasing steam generation efficiency and at the same time maintaining system compactness is a significant challenge in industrial thermal processes. Traditional smooth pipes offer limited heat transfer surface area, which constrains boiling heat transfer performance and reduces the overall efficiency of steam generation systems. Advanced internal geometries have the potential to significantly enhance heat transfer by increasing surface area and promoting fluid mixing. This work presents a …

Ignition Delay Time Measurements Of Natural Gas/Ammonia Mixtures At Gas Turbine Operating Conditions, Zachary A. Morris

Graduate Studies Theses and Dissertations 2026

Natural Gas/Ammonia (NG/NH₃) fuel blends are a promising route to reduce CO₂ emissions from gas turbines while leveraging existing NG infrastructure, but their autoignition behavior at elevated pressures is not yet well constrained. This work reports high-pressure shock tube ignition delay time (IDT) measurements for NG/NH₃/Air mixtures at gas turbine-relevant conditions. Experiments were performed at pressures of 5, 10, and 25 bar, temperatures from 1500 to 2100 K, with equivalence ratios of Φ = 1.0, 1.2, and 1.4, and argon-diluted fuel compositions spanning pure NH₃ to NG-rich blends. Experiments were carried out in two …

Revolution In The Age Of Social Media: A Mathematical Model For Information, Dissent, And Stability, Killian Muollo

Graduate Studies Theses and Dissertations 2026

Revolutions, defined by Skocpol as rapid transformations in class, state, and/or social structures, are important world events that can cause civil wars, spark international trends, and result in transitions toward democratic and autocratic regimes alike. They are characterized largely by the mechanism of mass mobilization, which is increasingly facilitated by online networks and digital communication. In this dissertation, we investigate such means and outcomes of revolutions as dynamical systems. We construct three models describing separate but complementary aspects of revolution, beginning at the smallest unit of analysis and then moving outward in scope. First, we construct a graph-based model to …

Study Of Compressibility Of Flames In Scramjet Combustors, Anirudh Ranganathan

Graduate Studies Theses and Dissertations 2026

Viable forms of propulsion for practical hypersonic flight are of great interest in modern times, of which supersonic combustion ramjets(scramjets) are a very advantageous option. Compared to ramjets, which are severely limited by increasing total pressure loss and dissociation effects, scramjets offer a much more efficient form of propulsion in the Mach 6 – 8 regime. Despite this, a common and unmitigated issue facing scramjet technology is scramjet unstart.

Prior investigations researching scramjet unstart have elucidated global heat release considerations in relation to total fueling or combustion modes as a result of global heat release . Minimal work has been …

Multibody Acausal Framework For Structural Dynamics Of Offshore Support Structures With Hydroelasticity And Soil-Structure Interaction, Saad Rahman

Graduate Studies Theses and Dissertations 2026

Offshore energy systems present significant challenges in support structure design due to their scale and the strong coupling between aerodynamic, hydrodynamic, and structural subsystems. These interactions make traditional sequential modeling approaches inefficient for design exploration. Acausal modeling frameworks address this limitation by enabling direct integration of coupled subsystems without reformulating governing equations, improving computational efficiency while preserving physical fidelity. This supports rapid exploration of large design spaces, accelerates iteration cycles, and shortens the path from concept to deployment.

This thesis develops and validates an acausal multibody elastodynamics model for offshore support structures. The framework includes structural flexibility to capture member-level …

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 …

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 …