Engineering Commons^™

Effect Of Composition On Grain-Boundary Chemistry And Fracture Behavior In High-Entropy Carbides, Caleb Schenck, Marium Mostafiz Mou, Elizabeth Pritchett, Fu Yun Tsai, Josephine Hartmann, Michael Lastovich, Sam Daigle, Kayla Yano, Matthew J. Olszta, Sanjit Bhowick, Elizabeth Kautz, Gregory E. Hilmas, William G. Fahrenholtz, Donald W. Brenner

Materials Science and Engineering Faculty Research & Creative Works

High-entropy carbides (HECs) are often treated as a single material class defined by configurational entropy; however, their properties are governed by composition-specific defects and grain-boundary chemistry. This study demonstrates that substituting a single element can qualitatively change grain-boundary structure and fracture behavior in HEC ceramics. Two HECs, (Cr,Hf,Ta,Ti,Zr)C (HEC-Cr) and (Hf,Ta,Ti,W,Zr)C (HEC-W), were examined via electron microscopy, atom probe tomography, and molecular dynamics simulations. Simulations predict preferential segregation of Cr, W, and Zr to grain boundaries. Experiments confirmed Cr enrichment at grain boundaries and the formation of W-rich nanograins along boundary networks. Mechanical testing revealed that these compositional differences translated …

Evaluating The Integration Of Bio-Based Waste Into Cement Production: A Pathway To Sustainable Building, Anja Terzić, Suzana Filipović, Adriana Peleš Tadić, Jelena Živojinović, Ivana N. Jelić, Nina Obradović, William G. Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

Rapid urbanization has increased the demand for building materials, depleting natural resources used in cement production and prompting the use of alternative and waste materials. This research verifies that eggshell powder waste can fully replace limestone in clinker synthesis. Five clinkers were produced using eggshell powder, aluminum sources (bentonite, zeolite, fly ash, and kaolinitic–illitic clay), Fe-slag, and quartz sand, with mechanical preprocessing (10–30 min) before sintering at 1300 °C. Experimental tests assessed the effects of mix design and mechanical activation on clinkerization, phase formation, temperature, and mechanical properties. XRD, FTIR, and SEM/EDS confirmed consistent phase compositions and primary cement minerals. …

In-Operando Imaging For Mechanistic Insights And Process Optimization In The Biofuel-Driven Combustion Synthesis Of Cement And Precursor Phases, Shubham Agrawal, Jeffrey J. Long, Aditya Kumar, Narayanan Neithalath

Materials Science and Engineering Faculty Research & Creative Works

Biofuel-based combustion synthesis (BCS) is a promising low-carbon pathway for decarbonizing cement production, providing an alternative to the fossil-fuel-driven clinkering process typically conducted at ∼1450 °C. Understanding microscale combustion mechanisms is essential to efficiently transfer biofuel-generated heat to cement precursors for targeted phase formation. Unlike previous studies focusing on macro-scale parameters such as fuel content/type, porosity, and holding temperature, this work provides mechanistic insights into microscale combustion behavior, linking microstructural phenomena with macro-scale processing conditions to guide parameter optimization. In-operando microscale imaging was employed to examine combustion wave propagation, spatio-temporal temperature evolution, and microstructural transformations within reactive pellets. Two combustion …

Strong And Ductile Additively Manufactured Ti-6al-4v Through Yttrium Inoculation, Saeid Alipour, Ji Young Kim, Min Seok Kim, Arezoo Emdadi, Ju Li

Materials Science and Engineering Faculty Research & Creative Works

The unique microstructural features and thermal cycles in alloys produced by additive manufacturing (AM) techniques have led to the emergence of a new paradigm in the design and development of alloys for performance-critical applications. Despite the inherent microstructural features of AMed parts, optimizing the porosity-microstructure while acquiring desired mechanical performance has been crucial yet challenging. Hence, in many legacy alloys, achieving a strength-ductility synergy in the as-built condition without applying post-heat treatment or hybrid processes is considered an arduous task. In this research, we aimed to tailor the microstructure of the legacy Ti-6Al-4V alloy in the as-built condition by implementing …

Atom Probe Tomography Investigation Of Gas And Solid Fission Product Superlattice In Neutron Irradiated U-10 Wt.% Mo Fuel, Maalavan Arivu, Andrew Hoffman, Anish Ranjan, Assel Aitkaliyeva, Yaqiao Wu, Brandon Miller, Mukesh Bachhav, Dennis Keiser, Jian Gan, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Body-centered cubic structured γ U-Mo fuels have been developed for high performance research reactors. The formation of Xe gas bubble superlattice (GBS) in irradiated U-Mo fuels reduces the volumetric swelling of the fuels. In this study, atom probe tomography (APT) was used to measure the characteristics of the Xe GBS, including chemical composition, number density, and volume fraction of the gas bubbles, as well as the characteristics of the solid fission products, in neutron irradiated U-10 wt.% Mo fuel. It was found that in the bubbles (∼2 nm in diameter) that form the GBS are enriched with Xe with depletion …

Integrated Geophysical, Geotechnical, And Mineralogical Characterization Of Expansive Weches Formation Soils In East Texas: Implications For Infrastructure Design, Samuel Annobil

Electronic Theses and Dissertations

This study investigates the geotechnical, geophysical, and mineralogical characteristics of soils derived from the Weches Formation in Nacogdoches County, East Texas, with emphasis on the relationships among electrical resistivity, moisture condition, compaction state, and mineralogical composition. The Weches Formation is well known for producing clay-rich, moisture-sensitive soils that pose challenges to subgrade performance because of their plasticity and swelling behavior. Representative soil samples were collected and subjected to laboratory testing, including particle size analysis, Atterberg limits, Standard Proctor compaction, free swell tests, electrical resistivity measurements, and X-ray diffraction (XRD) mineralogical analysis. The soils are predominantly fine-grained and clay-rich, with USCS …

Board-Level Operating System Infrastructure In Rust, Lydia Klaus

McKelvey School of Engineering Graduate Student Theses & Dissertations

Memory and multi-threading problems are the cause of many exploits and security vulnerabilities, and errors of this nature are easy to cause in programming languages such as C and C++. Despite this, these languages are still heavily used for systems programming and underpin the majority of operating system kernels. This is partially due to a lack of suitable replacements; however, Rust is becoming more prominent as an option for systems programming. This language features a much more stringent approach to memory and multi-threading safety. It also aims to support a wide range of hardware targets, including microcontrollers, which have long …

Data-Driven Multimodal Mri Representation Learning For Subtype Discovery And Disease Progression Modeling In Parkinson’S Disease, Zihan Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

Parkinson’s disease (PD) exhibits substantial clinical and neuroanatomical heterogeneity, limiting robust patient stratification and clinically meaningful progression modeling from MRI. We propose a unified multimodal 3D generative representation-learning framework that learns an interpretable latent space from co-registered baseline T1/T2 MRI with an edge-aware channel. Confound-corrected latent embeddings support unsupervised subtype discovery, while disease duration provides weak supervision to orient a continuous progression axis. On an independent external cohort (PPMI, N=171), the discovery-trained subtype structure shows significant partial replication (ARI=0.35; permutation test p=0.001) and enables longitudinal clinical stratification: mixed-effects modeling reveals subtype-dependent MDS-UPDRS III progression, with the strongest effect in subtype …

Analysis Of Oscillating Flow Over A 2-D Airfoil With Flow Reversal, Colter Couillard-Rodak

McKelvey School of Engineering Graduate Student Theses & Dissertations

Finite-state models are useful tools in modeling the aerodynamics of rotorcraft in flight simulators. 2-D and 3-D finite-state models have been developed and compared to closed form solutions, however these models are currently unable to handle situations where the freestream changes directions and the rotor re-enters its own wake. A 2-D finite state model was previously developed that includes a parameter that accounts for the change in free stream. This model, however, contains an inherent stability issue at the instant that the velocity changes direction.

The effects of this instability can be mitigated in certain flow conditions. A purely oscillatory …

Temporal Logic Planning In Semantic Maps Of Unknown Environments Using Tl-Rrt, Dongrui Yang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Autonomous mobile robots are increasingly expected to perform complex missions in unstructured environments. Traditional path planning approaches handle simple point-to-point navigation, but struggle with complex tasks that involve temporal and logical orderings of objectives. Linear Temporal Logic (LTL) provides a method for complex missions (e.g., sequential visits to multiple targets or surveillance tasks) in a strict way. This thesis presents an integrated planning framework that enables a robot to satisfy LTL-based task specifications in an unknown environment by combining a Temporal Logic RRT* (TL-RRT*) planner with semantic mapping. The robot builds a semantic map of its environment online using simultaneous …

Side-To-Side Differences In Three-Dimensional Femoral Head Coverage Associated With Initial Symptom Development In Patients With Bilateral Developmental Dysplasia Of The Hip, Jiayi Sun

McKelvey School of Engineering Graduate Student Theses & Dissertations

Developmental dysplasia of the hip (DDH) is characterized by insufficient acetabular coverage of the femoral head and is a recognized cause of hip pain, instability, and early osteoarthritis. Although bilateral deformity is common, symptoms often first develop in only one hip. The purposes of this study were: (1) to determine whether, in patients with bilateral DDH, side-to-side differences in three-dimensional (3D) femoral head coverage vary according to radiographic symmetry defined by the lateral center-edge angle (LCEA); and (2) to determine whether hips that appear radiographically symmetric still demonstrate focal 3D asymmetry.

This retrospective imaging-based study included patients with bilateral DDH …

Investigation Into The Effects Of Moderate-Dose Radiation On Ligament Biomechanics, Andrew Landefeld

All Theses

Recent advances in arthritis treatment pin ionizing X-ray radiation as a useful tool in reducing joint pain and immune response. However, due to a lack of fundamental research in the effects of low-dose ionizing radiation on tendon and ligament biomechanics, the safety of these studies is rather unknown. While most related studies investigated cellular response to low dose treatment, surrounding tissue physiology is left out of the picture. Additionally, moderate range doses of irradiation are rarely studied, as most uses of radiation on tendons and ligaments are for sterilization of cadaver tendons for allografts. This study provides a preliminary investigation …

Feasibility Study Of Transitioning From Thick Plates (0.250”) Mounted On 30-Point Pvc Carriers To Thinner Plate Technologies Mounted On Recyclable Foam And Pet (0.155”) For Post-Print Corrugated, Nathaniel J. Poole

All Theses

In the United States, the most common press configuration for brown-box printing is a 0.280” undercut press. These press configurations have long relied on thick 0.250” plates mounted on 0.030” PVC sheets to print onto corrugated substrates. Each year, around twenty million pounds of waste are produced by the printing industry, through paper waste, plate waste, among other materials. One large factor of that waste is flexographic plate waste, which either ends its life in a landfill or is repurposed into other products. This study establishes a comparison between traditionally used 0.250” plates on 30pt PVC versus 0.155” plates mounted …

Robust Hardware Trojan Detection Leveraging Dual‑Domain Features And Stacked Ensemble Learning, Sefatun-Noor Puspa

All Theses

In Cyber-physical systems rely on sensors, communication, and computing, all powered by integrated circuits (ICs). These ICs are vulnerable to malicious hardware attacks, with hardware Trojans being one of the stealthiest threats. Trojans are malicious implants in the circuitry, which are often inserted during design or fabrication stages. This stealthy addition remains dormant until triggered and might cause functional disruptions or sensitive information leakage once triggered. Traditional IC validation methods, such as functional testing and logic analysis, usually fail to capture these subtle anomalies because hardware Trojans are intentionally designed to mimic normal circuit behavior. They often remain dormant under …

Laser-Induced Acoustic Signal Generation, Resonance Characterization, And Optical Sensing In Metallic Plates, Xinghang Zhao

All Theses

This thesis investigates laser-induced acoustic signal generation, resonance characterization, and optical sensing in metallic plates as a foundational study for damage-sensitive inspection. Rather than presenting a complete defect-detection system, the work focuses on how measurable acoustic responses can be generated, amplified, and interpreted in a controlled laboratory setting. Experiments showed that pulsed-laser excitation can produce strong and repeatable acoustic responses in metallic structures. Repetition-rate sweeping identified narrow resonant responses, including a cantilever resonance at 57.862 kHz and a maximum circular-disk response at an FFT frequency of 48.8 kHz with a laser repetition rate of about 49.1 kHz. High-Q resonances exceeding …

Enhanced Situational Awareness Of Solar Pv Plants For Near Real-Time Planning And Operation In Modern Power Systems, Michael A. Walters

All Theses

Solar photovoltaic (PV) plant development and utilization is increasing worldwide but remains intrinsically challenged by its large dependence on highly variable weather conditions and operating states. This paper presents a framework to leverage three new situational awareness indices (SAIs), namely: weather condition index (WCI) to gauge operational performance based on environmental states, operational complexity index (OCI) to indicate the severity of power generation reductions, and photovoltaic generation index (PVGI) to provide a final determination of the impact on power generation and to bolster situational awareness in planning and operational contexts for solar PV plants. This is accomplished by exploiting the …

Field Testing Of Retrofits To Improve The Structural Behavior Of South Carolina Flat-Slab Bridges, Jacob Bowers

All Theses

The South Carolina Department of Transportation manages approximately 2,300 “flat-slab” bridges statewide, with an average age of 58 years, according to the National Bridge Inventory (NBI 2024). Many of these structures were originally designed for H10 or H15 truck loadings, which are significantly below current design standards. As a result, numerous bridges have been load-posted, restricting freight movement, emergency response, and local connectivity. While full replacement provides a long-term solution, it is often cost-prohibitive and disruptive. Accordingly, the South Carolina Department of Transportation is seeking cost-effective retrofit strategies that improve performance and extend the service life of these bridges. Implementing …

Estimation Of The Mechanical Properties Of South Carolina Timber Piles Using Non-Destructive Evaluation Methods And Experimentally-Informed Models, Aashish Sapkota

All Theses

South Carolina has about 2,600 bridges that are supported by nearly 75,000 timber piles. They are increasingly vulnerable to biological decay, cracking and impact damages after decades of service. Current inspection methods used by the South Carolina Department of Transportation (SCDOT), such as hammer sounding and awl probing, are labor-intensive and expensive. This study investigated non-destructive evaluation (NDE) methods, including micro-resistance drilling and stress wave timing, as alternatives for assessing timber pile condition.

Ten timber piles were collected from two South Carolina bridges, and their above-grade portions were cut into 40 specimens approximately 13 to 15 inches long. Specimens were …

Robustness Of Vision Language Models For Pedestrian Detection Tasks, Ostonya K. Thomas

All Theses

Autonomous vehicle (AV) systems typically employ modular systems in which discrete components handle separate tasks such as perception, computation, and path planning. While flexible, this approach allows errors to propagate and compound across the pipeline, and many AI systems offer little transparency into their internal decision-making. Such limitations are particularly concerning in safety-critical domains where failures can carry lethal consequences. Vision Language Models (VLMs) have emerged as a promising alternative because they support end-to-end implementations that bypass compounding error risks and provide natural language explanations of their outputs. Despite these advantages, prior research has demonstrated that both computer vision systems …

Multimodal Aerial Image-Based Ground Object Detection And Classification Using Yolo, Erik Nielsen

All Theses

Object detection in unmanned aerial vehicles (UAVs) present a unique challenge due to small object sizes, varying viewpoints, and changing environmental conditions. These challenges are exacerbated when operating during daytime and nighttime scenarios where illumination differences can heavily impact detection performance. This work is motivated by military object detection applications where the ability to reliably identify small objects such as landmines or unexploded ordnance from aerial imagery presents a critical safety need and a significant technical challenge. In this paper, we investigate object detection using both visible (RGB) and infrared (IR) imagery to improve robustness and reliability across diverse operating …

The Impact Of Dipeptides On Product Quality In Chinese Hamster Ovary Cells, Louise C. Herman

All Theses

Biopharmaceuticals are medicines produced in cells which are used to treat diseases such as cancer. Monoclonal antibodies (mAbs) represent the majority of approved biotherapeutics. MAbs are mostly produce using Chinese hamster ovary (CHO) cells. CHO cells are favored for resiliency, scalability, and established safety, and are considered the “workhorse” organism for biopharmaceuticals.  Amino acids are a key component of cell culture media, however several amino acids have solubility limits, such as cysteine, cystine, and tyrosine.  At neutral pH, these amino acids are poorly soluble.  However, dipeptides, such as N,N'-di-L-Alanyl-L-Cystine (ACCA) have been reported to increase cysteine and cystine availability. Further, …

Bayesian Assembly Tool For Intelligent Digital Twin Selection, Shishir Sharma

All Theses

Digital twins can be used for system performance optimization, health monitoring, predictive maintenance, and investigating system anomalies. A ground vehicle digital twin may be assembled using representations of the subsystem models (tires, suspension system, powertrain, etc.) of different fidelity. Lower fidelity Digital Twins have relatively simpler design and physics, hence are generally computationally less expensive, but may not represent the physical system accurately. On the contrary, higher fidelity Digital Twins are generally more precise in their ability to represent the physical system, but due to complexity, are usually computationally more demanding. This thesis describes the application of Bayesian Classification within …

Development Of Low-Cost Triaxial Force Sensor For Measurement Of Human-Exoskeleton Interaction Forces, Hamdan Khan Sarvathullah

All Theses

Contemporary research suggests that shear force is a major contributor to discomfort and pressure injury. However, the variation of shear forces during human-exoskeleton interaction dynamics is a highly unexplored field. The high cost of commercial triaxial force sensors may be a major factor in the notable lack of research in this field. Therefore, in this paper, we present a low-cost, 3D-printed triaxial force sensor designed specifically to measure the triaxial interaction forces between an exoskeleton and its user. The triaxial force sensor uses Carbon-Black/Silicone Rubber (CB/SR) strings to measure shear forces, whereas the normal force is measured with a Force …

Developing Aero-Floating Treatment Wetland (Aeroftw) Scaffolds: A Non-Plastic Alternative To Conventional Plastic-Based Ftws, Ada C. Montoya Gomez

All Theses

This research was conducted to explore the possibility of constructing floating treatment wetlands (FTWs) without using plastic materials. FTWs are floating platforms that hold plants on the water’s surface, letting roots dangle within the water column, to help remove contaminants from contaminated water, especially in stormwater ponds. Many conventional FTWs are made with plastic components, such as mats and plastic cup containers, which can release microplastics into the environment over time. The goal of this project was to design and test a new type of FTW that does not depend on plastics to support FTW flotation. The study took place …

Moodify: A Mood-Based Music Recommendation System, Meghana Kagitha

Theses and Dissertations

Music has long been recognised as a powerful tool for emotional regulation, yet existing music streaming platforms often fail to align song recommendations with a user's current emotional state. Moodify is a mood-based music recommendation system designed to bridge this gap by delivering personalised playlists that reflect how a user feels in real time.

This project presents the design, development, and evaluation of Moodify, a mobile application that leverages the Circumplex Model of Emotion to capture user mood through an intuitive two-dimensional valence-arousal interface. Rather than relying on text input or manual search, users plot their emotional state directly onto …

An Experimental Study On Turbine-Based Energy Harvesters For Thermal Underwater Gliders, Stephen Edward Coster

Theses and Dissertations

Buoyancy-driven underwater gliders have been optimized for long-duration missions primarily for continual monitoring of the ocean’s water column. However, longer missions and higher-powered sensors have increased the energy requirements of gliders. While current solutions aim to increase battery capacity, the development of energy-harvesting systems (EHMs) could greatly improve mission capabilities in both ability and duration. This thesis discusses the experimental testing of an underwater glider with an EHM as detailed in the theoretical study, “Development of a Turbine-Based Ocean Thermal Energy Harvesting Mechanism Applied to the Underwater Glider” by Hongbo Hou, PhD. The rear-mounted turbine captures energy using the kinetic …

Manned Exploration Of Satellites Of The Outer Planets: An Analysis Of Current Technologies And A Discussion Of Advancements Required, Joshua Carson Meador

Theses and Dissertations

The Solar System’s outer planets have many satellites, some of which are known to be the most likely places to find extraterrestrial life in our celestial backyard. Multiple scientific missions have been sent to glean information from these satellites, yet the possibility of a manned expedition has long been exclusive to science fiction stories. This paper intends to collect and analyze the current state of space travel technology to explore the feasibility of such a mission with modern technology and to discuss which future advancements should be the focal point for making such missions a reality. To begin, data on …

Hdra-Fusion: Hybrid Detection With Routed Architecture For Manipulation-Aware Ai Face Forgery Detection, Omar Ebeid

Theses and Dissertations

With the rapid advancements in artificial intelligence-based image generation and manipulation tools, it is extremely difficult to detect if an image is genuine or artificially crafted. Despite extensive research in this area, existing image detection systems suffer from three major problems: suboptimal cross-dataset generalization due to shortcut learning of dataset-specific patterns, unreliable probability estimates due to domain shift, particularly in cross-manipulation evaluation settings, and an inability to detect images manipulated by multiple types of manipulations within a single detection framework. To address these limitations, we propose HDRA-Fusion (Hybrid Detection with Routed Architecture), a framework built on the conclusion that different …

A Webcam Eye Tracking Infrastructure For Software Engineering Tasks, Zachary M. Kozak

School of Computing: Dissertations, Theses, and Student Research

Performing eye tracking utilizing commodity webcams has been explored for over a decade, but limited camera quality and sensitivity to head movements have hindered its adoption in research settings. Recent advances in consumer-grade webcams and machine learning methods present an opportunity to improve the accuracy of webcam eye tracking and extend the feasibility of studies beyond controlled laboratory environments.

Current popular webcam eye tracking methods restrict implementations to the browser and rely on continuous user interactions for calibration, limiting the kinds of studies that can be conducted. This thesis presents a feature-based gaze prediction system that incorporates eye geometry and …

Erratum For "Soil Freezing Characteristic Surface For Partially Frozen Soils", Antai Dong, Xiong Zhang, Ming Xiao

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The following corrections should be made to "Soil Freezing Characteristic Surface for Partially Frozen Soils" by Antai Dong, Xiong Zhang, and Ming Xiao, https://doi.org/10.1061/JGGEFK.GTENG -13924: In the third sentence of the Abstract, the value for suction when completely dried is incorrect. It should be 106 kPa. The label at the end of the suction axes in Figs. 1(a) and 2 is similarly inaccurate. Corrected versions of Figs. 1 and 2 are provided herein. To preserve the published version of record, these details have been corrected only in this erratum. (Figure Presented)