Engineering Commons^™

Design And Optimization To Advance Silicon Carbide Modules For Medium Voltage High Power Applications, Ahmed Ismail

Graduate Theses and Dissertations

The commercial availability of the first 10 kV silicon carbide (SiC) MOSFET removes the principal semiconductor barrier to medium-voltage power conversion, enabling converter topologies that are structurally inaccessible to silicon IGBT solutions at this voltage class. This dissertation presents the characterization infrastructure, device-level data, and preliminary system-level validation needed to advance the deployment of the third-generation 10 kV SiC MOSFET in converter applications. A custom-built 10 kV double-pulse test platform is developed with a fully documented component-sizing methodology, custom medium-voltage magnetics, and a measurement infrastructure capable of high bandwidth waveform capture at kilovolt common-mode potentials. On this platform, the third-generation …

Development And Characterization Of 1200v And 1700v Sic Schottky Barrier Diode For Power Electronics Applications, Nur-E-Afra Anika

Graduate Theses and Dissertations

The growing demand for energy-efficient, high performance power electronics in applications such as renewable energy systems, electric vehicles, industrial motor drives, and aerospace has accelerated the development of wide bandgap semiconductors like Silicon Carbide (SiC). This thesis focuses on the development and characterization of 1200V and 1700V SiC Schottky Barrier Diodes (SBDs), focusing on their performance optimization for power electronics applications. The key parameters and figure of merits for SiC Schottky barrier diode (SBD) is discussed. Commercially available 1200V and 1700V SBDs are characterized and key design parameters like drift region length, active area, and carrier concentration are extracted. The …

From Data Digitization To Personalized Care: Deep Learning And Decision Analytics In Healthcare Systems, Ahla Ko

Graduate Theses and Dissertations

This dissertation traces a progression from foundational data infrastructure to individualized clinical decision-making, developing and evaluating three computational frameworks that advance healthcare efficiency and personalization through deep learning and decision analytics. The first study presents an end-to-end pipeline for automated recognition of handwritten medical forms, addressing persistent challenges in health data digitization. Integrating a YOLO-based field detection model, a Convolutional Recurrent Neural Network (CRNN) for text transcription, and a confidence-based human-in-the-loop quality assurance framework, the system achieved 99.75\% Exact Match Accuracy and a 0.13\% Character Error Rate on medical forms collected from a tuberculosis research project in Moldova. A GPU-accelerated …

Analysis Of Potential Alkali Reactivity Of Aggregates In Arkansas, Brigita Dowling

Civil Engineering Undergraduate Honors Theses

Alkali Silica Reaction (ASR) is a deleterious chemical reaction in concrete that leads to the deterioration of concrete structures. This reaction occurs between minerals present in aggregates and alkalis in the cement, and produces a gel-like substance called alkali silicate gel. Gradually, these gels absorb water from the environment and expand, leading to internal stresses in the concrete. This damage results in expansion, cracking, and deformation, reducing the strength and durability of the concrete significantly. While this damage appears minor initially, eventually they can lead to the need for costly repairs or replacement of the concrete. ASR has been observed …

Chloronitramide Anion Yields During Monochloramine Formation: Impact Of Reagent Addition Order, Ph, And Mixing, Barrett E. Johnson, Julian L. Fairey, Jason A. Thornhill

Civil Engineering Undergraduate Honors Theses

Chloronitramide anion was recently identified as a decomposition product of inorganic chloramines. Tap‑water concentrations > 300 μg/L reported in a recent study prompted this investigation of chloronitramide anion during monochloramine formation under conditions relevant to drinking water treatment plants. As monochloramine is formed by mixing free chlorine with free ammonia, the impacts of pH, reagent mixing intensity, and reagent addition order were assessed on monochloramine and chloronitramide anion yields. Jar tests were conducted in distilled deionized water at target pH levels of 7 and 9 under rapid, slow, and no‑mixing conditions, with alternating reagent order addition and a target monochloramine dose …

Uav Blast Load Characterization For Structural Design, Jalee Grace Spain

Civil Engineering Undergraduate Honors Theses

As the use of drones, or UAVs, increases, so does the risk of collision with infrastructure. When drones collide with a building, an impact or blast load is applied. Using current literature and structural analysis, a load case can be defined for a blast load induced by a drone.

Spatial And Temporal Patterns Of Bike-Share Use In A Small City: A Case Study Of Fort Smith, Arkansas, Brianna L. Buenger

Civil Engineering Undergraduate Honors Theses

Many small and mid-sized cities in the United States face ongoing transportation challenges due to limited public transit options. This can prevent residents from being able to reach essential destinations. While bikeshare systems have been widely studied in large metropolitan areas, there is limited understanding of how usage patterns vary across space, time, and trip characteristics in small-city contexts. This study addresses this gap by examining spatial and temporal patterns of bikeshare use in a small U.S. city through a case study of the Fort Smith, Arkansas, SMILIES bikeshare program. Using approximately 10,000 trips over three years, the analysis examines …

Asynchronous Polymorphic Logic Locking, Kelby Haulmark

Graduate Theses and Dissertations

This work presents Asynchronous Polymorphic Logic Locking (APLL), a logic locking methodology that integrates polymorphic logic within the Multi-Threshold NULL Convention Logic (MTNCL) paradigm. APLL achieves Boolean satisfiability-attack resilience through a fault-based logic stripping approach followed by logic restoration, while leveraging the analog, dual-functionality of polymorphic gates to impede reverse engineering and removal attacks. In contrast to comparable SAT-resistant logic locking techniques, APLL provides inherent resistance to reverse engineering, reducing the viability of a broad class of attacks that rely on access to the locked netlist. A complete automated design flow is developed, enabling the transformation of combinational circuits into …

Cross-Facility Reliable Deep Learning Based Beef Marbling Assessment Via Unsupervised Domain Adaptation Regression, Samuel Vinson

Biological and Agricultural Engineering Undergraduate Honors Theses

Inconsistent quality grading in beef production leads to inefficiencies, economic disparity, and consumer mistrust. While USDA meat grading traditionally relies on skilled visual inspectors, these human evaluations suffer from cross-facility variability and subjectivity. This paper introduces the first known application of unsupervised domain adaptation regression for cross-facility beef marbling score prediction—an innovation that improves generalization across diverse environments in the beef supply chain. Utilizing numerical scores ranging from 100-900, the research employed convolutional neural networks (CNNs), including ResNet, VGG, and AlexNet architectures. The study specifically introduced and validated a unified unsupervised domain adaptation regression method using the ResNet-50 architecture to …

Retrospective Analysis Of Implemented Project Management Within A Small-Scale Student Engineering Project: Beng Fountain Wars Team Case Study, Holli E. Jenkins

Biological and Agricultural Engineering Undergraduate Honors Theses

This honors thesis provides a retrospective analysis of how the 2025 inaugural University of Arkansas’s ASABE Fountain Wars Student Team could be improved through project management. Project commitment, early stakeholder influence, rich communication, and a detailed project plan are all attributes of successful projects, and the team’s strengths and weaknesses within these categories were determined through a team poll. After the poll was conducted, three methodologies, Agile, Hybrid, and Waterfall, were assessed to determine how they would effectively address the team’s weaknesses. A weighted objectives table was created to compare each methodology’s effectiveness across the management categories. The analysis revealed …

Developing Transparent Sustainability Data Systems In A Poultry And Pet Food Company: An Internship Case Study, Catherine L. Warren

Biological and Agricultural Engineering Undergraduate Honors Theses

My honors thesis examined my internship experiences and its implications on sustainability data gathering and reporting in poultry and pet food companies. It highlighted my internship projects, the skills I developed, and the connections to sustainability data transparency and reliability in a corporate environment.

In my thesis, I shared details about my internship. I described what projects I worked on, the places I visited, the hands-on experience I gained, and the different teams I worked with throughout the internship duration. I discussed the analytic and professional skills I developed through conducting a waste audit, developing Tableau dashboards, and helping to …

Monitoring Streambank Morphology Using Iphone Lidar Technology, Lily C. Stitt

Biological and Agricultural Engineering Undergraduate Honors Theses

Monitoring stream morphology is crucial for maintaining the health and safety of fluvial environments, particularly as these naturally dynamic systems are shifted out of equilibrium due to climate and land-use change. Quantifying changes in stream geometry are useful for infrastructure design, water quality assessment, water resource management, and stream restoration, among other applications. Traditional stream surveying methods contain numerous cost limitations that inhibit affordable and accessible stream surveying needed for evaluating stream geometry with high accuracy and larger spatial scales (>100s of ). In recent years, several advancements have been made in the use of Light Detection and Ranging …

Per- And Polyfluoroalkyl Substances (Pfas) In Cave And Withrow Springs, Arkansas, Luke A. Ahlemeier

Biological and Agricultural Engineering Undergraduate Honors Theses

The class of chemicals known as Per- and Polyfluoroalkyl Substances (PFAS) are believed to be widespread in the natural environment, but the full extent of PFAS prevalence is not well understood, particularly in karst springs. The objectives of this study were to (1) collect water samples from Cave Springs and Withrow Springs, Northwest Arkansas, (2) measure for concentrations of 40 PFAS compounds using EPA Method 1633, and (3) compare differences in PFAS concentrations and discuss potential sources of PFAS for each spring. Each spring was sampled on September 29, 2025, October 13, 2025, and November 10, 2025, and water samples …

Dried Water Treatment Residuals Might Be An Option To Reduce Soluble Reactive Phosphorus Release From Soils, Katie B. Mckay

Biological and Agricultural Engineering Undergraduate Honors Theses

Nonpoint source pollution from agricultural landscapes contributes to freshwater eutrophication, with legacy phosphorus (P) in soils potentially driving soluble reactive phosphorus (SRP) losses to surface waters. The objectives of this study were to evaluate SRP adsorption by dried water treatment residuals (WTRs) produced by Beaver Water District, quantify reductions in soil SRP release across increasing WTR application rates, and compare dried WTR performance to prior WTR studies.

Dried WTRs (~98% solids) were assessed using batch sorption experiments and soil core incubations. Phosphorus sorption was measured by mixing WTRs with CaCl₂ solutions containing increasing SRP concentrations and fitting results to …

Enhancing Food Security In Stann Creek, Belize Using Meat Rabbits: Engineering Perspective, Lindsey Garretson

Biological and Agricultural Engineering Undergraduate Honors Theses

The purpose of this paper is to discuss the engineering perspective within the overall project of using meat rabbits to enhance food security and nutrition within Stann Creek, Belize. From the engineering perspective, the overarching goals were like the overarching project goals including the construction and materials required guide within the manual, designing potential upgrades to the design including a solar and battery system and an automatic watering system, and to design the system to be “practically sustainable” where possible. The constraints for this project included cost, the size of land dedicated for the rabbitry, and the operational and environmental …

A Systems Approach To Nitrogen Fertilizer Management: Modeling Emissions And Runoff Pathways In Arkansas Agriculture, Avonelle Lindon

Biological and Agricultural Engineering Undergraduate Honors Theses

Nitrogen fertilizer management is a critical challenge in modern agriculture. This thesis develops a system dynamics model of nitrogen in Arkansas rice and corn systems to explore barriers to translating agricultural research into practical farmer guidance.  The modeling process revealed key challenges: (1) scarcity of Arkansas-specific factors and best management practice (BMP) effectiveness data; (2) tension between model comprehensiveness and accessibility; (3) misalignments in conservation incentive structures; and (4) difficulty in validating models without field measurements. The resulting model demonstrates basic nitrogen cycle processes and BMP integration, but validation against published literature revealed significant issues with predictive accuracy. These findings …

Uav-Based Sensor Integration For In-Situ Lake Water Quality Monitoring, Alec R. Campbell

Biological and Agricultural Engineering Undergraduate Honors Theses

Surface water monitoring is often constrained by limited spatial and temporal coverage due to the labor-intensive nature of traditional sampling methods, particularly in environments that are difficult to access or pose safety risks. Unmanned aerial vehicles (UAVs) offer a promising solution by enabling more frequent, spatially distributed, and cost-effective data collection. This study presented the design, development, and field evaluation of a UAV-based system for real-time, in-situ water quality monitoring. The system integrated multiple sensors, including oxidation-reduction potential (ORP), RGB spectrometry, pH, electrical conductivity (EC), dissolved oxygen (DO), and a multispectral spectrometer within a UAV platform.

Field testing was conducted …

Design And Performance Overview Of The Inaugural University Of Arkansas Beng Fountain Wars Team, Autumn Jones

Biological and Agricultural Engineering Undergraduate Honors Theses

This honors thesis describes the engineering design process for the first ASABE Fountain Wars submission by a student team at the University of Arkansas in over a decade. Fountain Wars has a technical and aesthetic task, and the focus of this thesis is the design of the technical task. In 2025, this task was the “shoot out.” The objective was to get objects from a small pool into two 5-gallon buckets 10-15 feet away. The power for initiating the launch had to be provided by the pump. The objects were required to start at the surface of the water.

The …

Online Path Planning For Disaster Response In The Presence Of Unknown Road Disruptions: A Comparison Of Research And Practice, Jannatul Shefa, Ashlea Bennett Milburn, Erica Gralla

Industrial Engineering Faculty Publications and Presentations

Purpose This paper aims to illuminate gaps between theory and practice in one crucial area of disaster logistics: transportation management between staging areas and final destinations, on uncertain and disrupted road networks. Relevant current practice in federal, state, nonprofit and private disaster response organizations in the USA is described and compared to pertinent assumptions in the literature on disaster response online path planning under uncertainty. Design/methodology/approach The study uses a qualitative approach. The disaster response routing literature informed the development of an interview guide used for in-depth interviews with disaster response logistics practitioners. Collected data were coded to identify how …

Control And Stability Analysis Of Three-Phase Grid-Connected Inverters In Renewable Energy Systems, Yasser Ayeva

Electrical Engineering and Computer Science Faculty Publications and Presentations

The increase in demand for renewable energy sources such as solar and wind systems has led to widespread use and integration of a three-phase grid connected inverters in electric modern electric power systems. The inverters are essential to convert DC power into AC power and to control the delivered power to the grid. However, the use of the inverters in a renewable energy system has some challenges related to stability and control due to the presence of power electronic interfaces and filter dynamics. This paper analyzes the control and stability of three phase grid connected inverter through an LCL filter. …

A Runtime-Adaptive Transformer Neural Network Accelerator On Fpgas, Ehsan Kabir, Jason D. Bakos, David Andrews, Miaoqing Huang

Electrical Engineering and Computer Science Faculty Publications and Presentations

Transformer neural networks (TNN) excel in natural language processing (NLP), machine translation, and computer vision (CV) without relying on recurrent or convolutional layers. However, they have high computational and memory demands, particularly on resource constrained devices like FPGAs. Moreover, transformer models vary in processing time across applications, requiring custom models with specific parameters. Designing custom accelerators for each model is complex and time-intensive. Some custom accelerators exist with no runtime adaptability, and they often rely on sparse matrices to reduce latency. However, hardware designs become more challenging due to the need for application-specific sparsity patterns. This paper introduces ADAPTOR, a …

In Situ And Operando Microscopy Studies On Lithium Metal Anodes: A Review, Ian Lindsey, Cameron Mondl, Xiangbo Meng

Mechanical Engineering Faculty Publications and Presentations

Lithium metal is regarded as an ultimate anode for rechargeable batteries, ascribed to its extremely high capacity. Its implementation can remarkably boost the energy density of the resultant lithium metal batteries. However, it is very challenging to commercialize lithium metal anodes, primarily due to the intertwined nature of the formation of a solid electrolyte interphase (SEI) and the growth of lithium dendrites. To understand these issues and therefore develop technical solutions, various instrumental techniques have been employed. This review highlights the most recent advancements of in situ and operando microscopy studies that are critical for investigating and addressing the issues …

The Effects Of Membrane Structure And Filtration Conditions On Virus Filtration, Wenbo Xu, Xianghong Qian, Hironobu Shirataki, Daniel Strauss, Sumith R. Wickramasinghe

Biomedical Engineering Faculty Publications and Presentations

Virus filtration is used for validation of virus clearance in the manufacture of monoclonal antibodies. Requirements for this size exclusion process include 10,000-fold reduction of virus particles and at least 95 % recovery of the monoclonal antibody in the permeate. The size difference between the rejected parvovirus particles, 25 nm, and monoclonal antibody, 10-12 nm, is about two. Membranes are designed with pore sizes around the average size of the parvovirus. Given the polydispersity in membrane pore size and virus particles, filter performance is dependent on membrane properties, feed and operating conditions. Compromised performance usually occurs due to product related …

Perception Of Transportation Challenges And Their Influence On Mode Choice In A Small Us City: A Generalized Structural Equation Modeling Approach, Anindya Kishore Debnath, Suman Kumar Mitra

Civil Engineering Faculty Publications and Presentations

This study profiles individuals encountering transportation challenges by analyzing factors influencing their perceptions and how they affect mode choice decisions in Fort Smith, Arkansas. Using primary travel survey data, we estimated a multinomial logit (MNL) within a Generalized Structural Equation Model (GSEM) that controls for residential self-selection and car ownership endogeneity. We find that individuals from low-income households are more likely to perceive transportation challenges, particularly due to a lack of a car and inadequate public transport. Higher household car ownership generally diminishes perceived challenges, except regarding limited bike lanes. Weekend or late-shift workers are more likely to own cars …

Delay-Doppler Integrated Sensing And Communications (Dd-Isac) With Predictive Beamforming, Mohammad Abdul Mobin, Yanjun Pan, Jingxian Wu

Electrical Engineering and Computer Science Faculty Publications and Presentations

A new delay-Doppler (DD) integrated sensing and communications (ISAC) framework is proposed for unmanned aerial vehicle (UAV) systems. In the DD-ISAC framework, both sensing and communications are performed by using the orthogonal delay Doppler division multiplexing (ODDM) waveforms, which unify sensing and communication designs through the unique ODDM waveform properties, such as local DD-domain bi-orthogonality and dual-resolution. Specifically, the dual-resolution property enables the generation of a range-Doppler map for accurate and low complexity sensing, and the bi-orthogonality minimizes interference for both sensing and communications. The ODDM waveforms are used in combination with the phase comparison monopulse technique and a scaled …

Evaluating High-Strength Steel Welded Connections For Future Aws Welding Standards, Parker Minter

2026 Research Poster Competition

Welding plays a critical role in many civil engineering applications as it is a common method used to connect structural steel components. Because of how widespread the practice is, the American Welding Society (AWS) has developed a set of standardized welding guidelines to ensure consistent quality in structural welds. These standards allow common weld types to be fabricated using pre-approved procedures (e.g. welding materials, temperatures, and positions). Recently, high-strength structural steels have begun to be available domestically. Current AWS standards do not allow for high strength steels (yield strength greater than 80ksi) and need to be evaluated for the inclusion …

Unmanned Aircraft Vehicle Safety Reporting And Analysis Of Incidents Utilizing Machine Learning, Cody Harrison

2026 Research Poster Competition

Unmanned Aerial Vehicles (UAVs) are rapidly evolving and being integrated into a wide range of applications, from commercial deliveries to police surveillance and recreational use. As UAVs become more prevalent, the complexity of operations and potential for incidents or accidents will continue to increase. Understanding why these incidents and accidents occur is critical to ensure safe and reliable drone operations as the industry continues to grow. To combat these issues, it is invaluable to analyze UAV incidents quantifiably to identify leading causes and risks in a streamlined and efficient matter. Current manual reporting systems often struggle with the sheer volume …

How Do Different Flight Training Programs Impact Pilot Proficiency?, Abigail Henson

2026 Research Poster Competition

The Federal Aviation Administration (FAA), founded in 1958, ensures safe and efficient use of national airspace by regulating aircraft and pilot certification, setting standards for airports, and managing the National Airspace System. One such regulation is in the certification process for aspiring student pilots. Students who want to obtain their private pilots license can do so by picking either a Part 61 or Part 141 flight school. While both lead to the same certification, these two options differ significantly in terms of structure; Part 61 programs offer flexibility with their individualized approach and fewer requirements while Part 141 schools follow …

Analysis Of Loss Of Engine Power Events In General Aviation, Saloni Satappagol

2026 Research Poster Competition

Among different parts of aviation, general aviation (GA) stands out as one of its largest and most vital sectors. GA is defined as any civil aviation activity excluding scheduled commercial flights and military operations. While loss of engine power is a serious subset of general aviation accidents, accounting for more than 200 fatal accidents per year, several gaps remain in our current understanding of these accidents. While current literature includes older studies from 2000-2014, new data from the past decade have not been analyzed for trends yet. With this significant gap of more than a decade in understanding, it is …

Monitoring Eye Movements To Assess The Impact Of Sensory Feedback On Cognitive Workload During Myoelectric Prosthetic Hand Use, Naomi Tchoungang, Hailey Dirrigl, Justin Asbee

2026 Research Poster Competition

Modern prosthetic hands allow users to grasp and manipulate objects, but many users must constantly watch the device to complete even simple tasks. This heavy reliance on vision increases cognitive effort, slows movement, and makes prosthetic use feel less natural. An important question in prosthetics research is whether providing sensory feedback (enabling users to feel what the prosthetic hand is doing) can reduce this cognitive load and improve performance. In this study, sensory feedback refers to a system that provides clear tactile cues to the user upon contact between the prosthetic hand and an object, helping replace information normally felt …