Engineering Commons^™

Model-Free Methods To Analyze Pmu Data In Real-Time For Situational Awareness And Stability Monitoring, Sean Kantra

All Dissertations

This dissertation presents and evaluates model-free methodologies to process Phasor Measurement Unit (PMU) data. Model-based PMU applications require knowledge of the system topology, most frequently the system admittance matrix. For large systems, the admittance matrix, or other system parameters, can be time-consuming to integrate into supporting PMU applications. These data sources are often sensitive and can require permissions to access, delaying the implementation of model-based approaches. This dissertation focuses on evaluating individual model-free applications to efficiently perform functions of interest to system operators for real-time situational awareness. Real-time situational awareness is evaluated with respect to central digitization where the PMU …

Physics-Based Machine Learning Methods For Control And Sensing In Fish-Like Robots, Colin Rodwell

All Dissertations

Underwater robots are important for the construction and maintenance of underwater infrastructure, underwater resource extraction, and defense. However, they currently fall far behind biological swimmers such as fish in agility, efficiency, and sensing capabilities. As a result, mimicking the capabilities of biological swimmers has become an area of significant research interest. In this work, we focus specifically on improving the control and sensing capabilities of fish-like robots.

Our control work focuses on using the Chaplygin sleigh, a two-dimensional nonholonomic system which has been used to model fish-like swimming, as part of a curriculum to train a reinforcement learning agent to …

Structural Characterization Of Cardiomyocyte Microenvironment In Murine Myocardium By Multimodal Stimulated Emission Depletion Microscopy, Zhao Zhang

All Dissertations

Cardiomyopathy, a disease of the heart muscle, is characterized by structural and functional abnormalities of the myocardium, in the absence of coronary artery disease, hypertension, valvular disease or congenital heart disease. In 2020, there were approximately 6.11 million prevalent cases of cardiomyopathy and myocarditis, and 0.37 million related deaths worldwide. Many affected individuals are asymptomatic, and chronically treated patients are at risk of heart failure. Within the myocardium, cardiomyocytes reside in a complex and dynamic extracellular matrix (ECM), consisting of basement membrane and interstitial matrix. The interactions between cardiomyocytes and myocardial ECM play a critical role in maintaining cardiac geometry …

Feasibility Of Using High-Alkali Natural Pozzolans And Reclaimed Fly Ash As Alternative Supplementary Cementitious Materials In Concrete, Weiqi Wang

All Dissertations

Due to the shortage of supplementary cementitious materials (SCMs) in the concrete industry, it is necessary to seek a new alternative. This study evaluates the feasibility of high-alkali SCMs, which were not recommended previously due to potentially exacerbating alkali-silica reaction (ASR) in concrete. The study addresses theSCMs’ ASR mitigation performance, evaluated by ASTM C1567, C1293, and AASHTO T380. Other concrete durability tests, including ASTM C596 drying shrinkage test, ASTM C1012 sulfate resistance test, and ASTM C1202 rapid chloride ions penetration test, were also conducted in this study. The ASTM C311 strength activity index test, thermal gravimetric analysis (TGA), and ASTM …

Ti-6al-4v Β Phase Selective Dissolution: In Vitro Mechanism And Prediction, Michael A Kurtz

All Dissertations

Retrieval studies document Ti-6Al-4V β phase dissolution within total hip replacement systems. A gap persists in our mechanistic understanding and existing standards fail to reproduce this damage. This thesis aims to (1) elucidate the Ti-6Al-4V selective dissolution mechanism as functions of solution chemistry, electrode potential and temperature; (2) investigate the effects of adverse electrochemical conditions on additively manufactured (AM) titanium alloys and (3) apply machine learning to predict the Ti-6Al-4V dissolution state. We hypothesized that (1) cathodic activation and inflammatory species (H₂O₂) would degrade the Ti-6Al-4V oxide, promoting dissolution; (2) AM Ti-6Al-4V selective dissolution would occur …

A Digital Triplet For Utilizing Offline Environments To Train Condition Monitoring Systems For Rolling Element Bearings, Ethan Wescoat

All Dissertations

Manufacturing competitiveness is related to making a quality product while incurring the lowest costs. Unexpected downtime caused by equipment failure negatively impacts manufacturing competitiveness due to the ensuing defects and delays caused by the downtime. Manufacturers have adopted condition monitoring (CM) techniques to reduce unexpected downtime to augment maintenance strategies. The CM adoption has transitioned maintenance from Breakdown Maintenance (BM) to Condition-Based Maintenance (CbM) to anticipate impending failures and provide maintenance actions before equipment failure. CbM is the umbrella term for maintenance strategies that use condition monitoring techniques such as Preventive Maintenance (PM) and Predictive Maintenance (PdM). Preventive Maintenance involves …

Atomistic And Mesoscale Modeling Of Microstructure Development During Solid-State Sintering, Omar Marwan Isa Hussein

All Dissertations

Interfaces are ubiquitous in materials systems, and they influence the processing and properties of nearly all engineering and functional materials. Examples include grain boundaries (GBs) in polycrystalline materials, free surfaces in nanoparticles, and phase boundaries in multiphase materials. Therefore, understanding and controlling interfacial processes is a key aspect of materials design and discovery efforts. Recent developments in advanced manufacturing and synthesis techniques have enabled the fabrication of materials architectures with intricate nanoscale features. Of particular interest is solid-state sintering, known for creating complex and high-precision geometries with controlled microstructures. While sintering science has been the subject of active research, very …

Improving Hexapod Platform Pose Accuracy - A Photogrammetry-Based Approach, Sourabh Karmakar

All Dissertations

The aim of this research is to make a newly constructed Stewart-Gough Platform-based test frame Tiger 66.1 operational by developing control software and estimating the error in its pose accuracy. The accuracy of the platform is affected by one source or multiple sources. The typical error sources are kinematic and structural, some of them originate from manufacturing imperfections, assembly deviations, elastic deformations, thermal deformations, and joint clearances which change the expected kinematic behavior of the manipulator. Also, some non-mechanical errors like transmission error, sensor accuracy, algorithm error, and truncation error in calculation contribute significantly in some cases. Using pose deviations …

Atomistic And Mesoscale Modeling Of Microstructure Development During Solid-State Sintering, Omar Hussein

All Dissertations

Interfaces are ubiquitous in materials systems, and they influence the processing and properties of nearly all engineering and functional materials. Examples include grain boundaries (GBs) in polycrystalline materials, free surfaces in nanoparticles, and phase boundaries in multiphase materials. Therefore, understanding and controlling interfacial processes is a key aspect of materials design and discovery efforts.

Recent developments in advanced manufacturing and synthesis techniques have enabled the fabrication of materials architectures with intricate nanoscale features. Of particular interest is solid-state sintering, known for creating complex and high-precision geometries with controlled microstructures. While sintering science has been the subject of active research, very …

Exploring Modalities Of Productivity And Critical Quality Attributes In Fed-Batch Chinese Hamster Ovary Cell Cultures, Stephanie Klaubert

All Dissertations

Chinese hamster ovary (CHO) cells are among the most commonly used mammalian cell lines for the production of recombinant therapeutic proteins due to ease of culturing and humanlike post-translational modification capabilities. However, when compared to microbial systems, CHO cell line growth and productivity is relatively low. As the demand for monoclonal antibody (mAb) treatments continues to rise, it is critical to explore modalities for improved growth and productivity in CHO cell cultures, with the goal of increased protein concentrations and maintained product quality. Though some mechanisms for improved productivity, including temperature and cell culture media formulations, are relatively well understood; …

Towards Enabling Usable Batteryless Wearables, Arwa Alsubhi

All Dissertations

Wearable devices have become ubiquitous in modern technology, providing a convenient way for a large number of users to monitor their health and track their daily activities. However, despite their numerous benefits, wearable devices are not without their challenges. One of the most significant issues is the need to recharge their batteries, which can disrupt users’ daily routines and might result in the discontinuation of device use.

Replacing batteries with capacitors and charging them using the available harvested energy from the surrounding environment (e.g., kinetic, thermal, or solar energy) eliminates the burden of recharging or replacing batteries, resulting in convenient, …

Engineering Next-Generation Cardiovascular Therapies, Ryan Walker Barrs

All Dissertations

Cardiovascular diseases are the leading cause of death worldwide. Heart disease, in particular, accounted for 1 in every 5 deaths in the United States in 2021, representing a substantial public health burden that will require more effective treatment options to alleviate. Heart transplant surgery is currently the only option to completely restore cardiac function, but many patients die while waiting for a transplant due to a longstanding organ donor shortage. Thus, there is a dire need for accessible treatment options that can repair damaged hearts. Recent advances in tissue engineering and regenerative medicine have accelerated the development of therapies for …

Improving Sizing Resolution Of Particle Impactors In The Nanoparticle Range, Shivuday Kala

All Dissertations

The application of particle size measurement extends across many fields: air quality measurement, pharmaceutical studies, paint and coating production, and nanoparticle formulation to name a few. Therefore, accurate measurement of nanoparticles is critical to aerosol science. While devices currently exist that can size and count nanoparticles such as electrical mobility spectrometers, dynamic light scattering devices, and small angle X-ray scattering devices, their high costs, complex operation, and lack of outdoor usability, restrict their use in practical applications. Among the devices that can size aerosols down to the nanoscale, cascade impactors stand out because of their robustness, relatively simple design, low …

Embracing Identities And Affirming Agency: Exploring Effective Mentorship For Women Doctoral Students In Engineering Disciplines Using An Intersectional Lens, Jennifer Brown

All Dissertations

Positive mentoring experiences are crucial for retaining and advancing those who hold marginalized identities in STEM, as they foster a greater sense of belonging and self-efficacy that encourage these students to persist in their fields. Marginalized identities in STEM include, but are not limited to, women, BIPOC (Black, Indigenous, and People of Color), low-income, first-generation, neurodivergent, and members of the LGBTQ+ community. Oftentimes, these identities intersect, introduce additional nuance in interactions within engineering spaces, and affect the mentoring support that both mentees and their mentors require.

Prior research has shown the reciprocal value that is created when graduate students are …

Experimental And Computational Platforms For Studying Systems Mechanobiology, Brendyn Miller

All Dissertations

Mechanical stimulation through physical activity has been shown to play an important role in treating and preventing several non-communicable diseases such as hypertension, lower back pain (LBP), type-2 diabetes mellitus, and several cancers. This is accomplished through the regulation of cellular behavior and tissue remodeling within the body at both the micro- and macro-scale levels. The goal of mechanobiology research is to gain in-depth knowledge and understanding of how cells sense physical forces in conjunction with other biochemical cues and translate those factors into important biological functions that either maintain tissue homeostasis or lead to pathological states. Understanding these processes …

Hpc-Enabled Fast And Configurable Dynamic Simulation, Analysis, And Learning For Complex Power System Adaptation And Control, Cong Wang

All Dissertations

This dissertation presents an HPC-enabled fast and configurable dynamic simulation, analysis, and learning framework for complex power system adaptation and control. Dynamic simulation for a large transmission system comprising thousands of buses and branches implies the latency of complicated numerical computations. However, faster-than-real-time execution is often required to provide timely support for power system planning and operation. The traditional approaches for speeding up the simulation demand extensive computing facilities such as CPU-based multi-core supercomputers, resulting in heavily resource-dependent solutions. In this work, by coupling the Message Passing Interface (MPI) protocol with an advanced heterogeneous programming environment, further acceleration can be …

Addressing Mercury Contamination From Artisanal Gold Mining In Colombia: Pollution Exposure, Health Risk, And Educational Efforts In The Communities Of La Toma, Colombia, Kelli Mccourt

All Dissertations

Artisanal and small-scale gold mining (ASGM) has become a primary environmental and public health concern in the region of Colombia known as Alto Cauca. The predominantly Afro-descendent communities of Yolombó and La Toma in Alto Cauca have experienced pollution linked to the use of mercury in the ASGM process. For the past decade, mercury has emerged as a contaminant of increasing concern in the communities due to its toxicity and ability to bioaccumulate and biomagnify. Likewise, mining in the region raises concerns over the leaching of metals into local waters. Given the complexity of risk and pollution in the communities, …

A Scalable Transmission And Distribution Co-Simulation Platform For Ibr-Heavy Power Systems, Yousu Chen

All Dissertations

The grid is evolving rapidly to meet the requirements of the clean energy transition. This evolution involves an increasing penetration of renewable energy resources and new complexities with a larger number of devices and controls spread across transmission and distribution networks. The boundary between transmission and distribution becomes blur. Consequently, we face significant challenges in managing the fundamental shift in power system physics. The ubiquitous use of Inverter Based Resources (IBRs) throughout the transmission and distribution systems has made it more difficult for the grid to maintain grid stability under dynamic conditions. Therefore, there is a strong need to explore …

Influence Of Photoreactor Design Parameters On The Performance Of Ultraviolet Light-Induced Degradation Of Per-And Polyfluoroalkyl Substances By Bismuth Oxy Hydroxy Phosphate And Hexagonal Boron Nitride Photocatalystsinfluence Of Photoreactor Design Parameters On The Performance Of Ultraviolet Light-Induced Degradation Of Per-And Polyfluoroalkyl Substances By Bismuth Oxy Hydroxy Phosphate And Hexagonal Boron Nitride Photocatalysts, Mojtaba Qanbarzadeh

All Dissertations

The main objective of this study is to evaluate the practical applicability of heterogeneous photocatalysis technology powered by ultraviolet (UV) photons for the degradation of per and -polyfluoroalkyl substances (PFAS) in contaminated groundwater samples. For this purpose, bismuth oxyhydroxy phosphate (BOHP) and hexagonal boron nitride (hBN) were utilized as the main photocatalysts in slurry photodegradation systems. BOHP (Bi₃O(OH)(PO₄)₂) is a wide bandgap semiconductor with high activity for degrading long-chain perfluorocarboxylic acids (PFCAs) in mild operational conditions. Boron nitride (BN) is another wide bandgap semiconductor material that was used in this study due to its …

Citrate Hydrogels For Regenerative Medicine Applications, Mark Pitman

All Dissertations

Regenerative medicine focuses on restoring cells and tissues to re-establish proper function. Hydrogels are a customizable and adaptable set of materials that can be engineered as tools for regenerative medicine. My research has focused on developing and applying biomaterials to spinal cord injury and chronic wounds. Spinal cord injury and chronic wounds share pathophysiological issues with oxidative stress, excess free, and macrophage polarization. Furthermore, both conditions lack robust, effective treatments. We hypothesized that citrate hydrogels – hydrogels that contain citric acid as a functional component – would provide radical scavenging and iron chelation that would benefit both conditions. The hydrogels …

Damage Detection With An Integrated Smart Composite Using A Magnetostriction-Based Nondestructive Evaluation Method: Integrating Machine Learning For Prediction, Christopher Nelon

All Dissertations

The development of composite materials for structural components necessitates methods for evaluating and characterizing their damage states after encountering loading conditions. Laminates fabricated from carbon fiber reinforced polymers (CFRPs) are lightweight alternatives to metallic plates; thus, their usage has increased in performance industries such as aerospace and automotive. Additive manufacturing (AM) has experienced a similar growth as composite material inclusion because of its advantages over traditional manufacturing methods. Fabrication with composite laminates and additive manufacturing, specifically fused filament fabrication (fused deposition modeling), requires material to be placed layer-by-layer. If adjacent plies/layers lose adhesion during fabrication or operational usage, the strength …

Testing And Implementation Of Attitude Determination & Control System For Arksat-1 Cubesatellite, Cassandra Sands

Graduate Theses and Dissertations

ARKSAT-1 is a CubeSatellite (CubeSat) developed at the University of Arkansas and launched to the International Space Station on SpaceX mission SPX-27 launching from Kennedy Space Center as part of the NASA’s 8th CubeSat Launch Initiative CSLI-8. ARKSAT-1’s payload features a high-powered LED, the Solid State Inflatable Balloon (SSIB) deorbiting system applicable to small satellites, and a series of InfraRed and Visible cameras. To point the LED or take images of desired observational targets, the spacecraft will need to be able to determine its orientation within its orbit, as well as rotate. This will be achieved through the use of …

Towards Multi-Modal Interpretable Video Understanding, Quang Sang Truong

Graduate Theses and Dissertations

This thesis introduces an innovative approach to video comprehension, which simulates human perceptual mechanisms and establishes a comprehensible and coherent narrative representation of video content. At the core of this approach lies the creation of a Visual-Linguistic (VL) feature for an interpretable video portrayal and an adaptive attention mechanism (AAM) aimed at concentrating solely on principal actors or pertinent objects while modeling their interconnections. Taking cues from the way humans disassemble scenes into visual and non-visual constituents, the proposed VL feature characterizes a scene via three distinct modalities: (i) a global visual environment, providing a broad contextual comprehension of the …

Real-Time Analysis Of Aerosol Size Distributions With The Fast Integrated Mobility Spectrometer (Fims), Daisy Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

The Fast Integrated Mobility Spectrometer (FIMS) has emerged as an innovative instrument in the aerosol science domain. It employs a spatially varying electric field to separate charged aerosol particles by their electrical mobilities. These separated particles are then enlarged through vapor condensation and imaged in real time by a high-speed CCD camera. FIMS achieves near 100% detection efficiency for particles ranging from 10 nm to 600 nm with a temporal resolution of one second. However, FIMS’ real-time capabilities are limited by an offline data analysis process. Deferring analysis until hours or days after measurement makes FIMS' capabilities less valuable for …

Component Approach For A Combined Hurricane Wind And Rainwater Damage And Time Related Expenses Model In Mid/High-Rise Buildings, Zhuoxuan Wei

Theses and Dissertations

This dissertation focuses on mid/high-rise commercial residential buildings (MHRB) vulnerable to wind-driven rainwater ingress during hurricanes. The author developed the WHIP-MHRB model, a new probabilistic vulnerability model funded by the Wind Hazard Infrastructure Performance Center (WHIP-C). This model combines the estimates of rainwater ingress, distribution and propagation, and damage assessments, and time-related expenses (TRE) predictions for MHRB during hurricanes. Embedded within WHIP-MHRB is the WHIP-TRE model, which forecasts repair times, delay times, downtime, and recovery times post-hurricane explicitly.

Furthermore, taking advantage of the new model, this study presents two approaches to address the combined wind and rain vulnerabilities of MHRB …

Assessing The Thermodynamic Potential Of Deep Eutectic Solvents In The Absorption Of Greenhouse Gases Through Computational Methods, Thomas Michael Quaid

Theses and Dissertations

Greenhouse gas (GHG) capture is a fundamental technology in the fight against climate change. Some species of devastating GHGs like fluorinated compounds are released directly to the air from industrial processes. Some GHGs are co-produced in sustainably derived biofuels which require absorptive upgrading. The development of more efficient, cost effective, and environmentally friendly methods of capturing GHG’s from pollutant sources and industrial streams is of utmost importance in the fight against climate change. Deep eutectic solvents have entered the separations stage as potential disruptors to conventional solvent choices for a variety of applications. Deep eutectic solvents (DES) are compounds of …

Accelerating Machine Learning Inference For Satellite Component Feature Extraction Using Fpgas., Andrew Ekblad

Theses and Dissertations

Running computer vision algorithms requires complex devices with lots of computing power, these types of devices are not well suited for space deployment. The harsh radiation environment and limited power budgets have hindered the ability of running advanced computer vision algorithms in space. This problem makes running an on-orbit servicing detection algorithm very difficult. This work proposes using a low powered FPGA to accelerate the computer vision algorithms that enable satellite component feature extraction. This work uses AMD/Xilinx’s Zynq SoC and DPU IP to run model inference. Experiments in this work centered around improving model post processing by creating implementations …

A Repository Of Occupant-Centric Control Case Studies: Survey Development And Database Overview, Clara-Larissa Lorenz, Maíra André, Oliver Abele, Burak Gunay, Jakob Hahn, Philipp Hensen, Zoltan Nagy, M. Mohamed Ouf, Young June Park, Nikhil Yaduvanshi Singh, Clayton Miller

Research Collection College of Integrative Studies

Occupant-centric controls (OCC) and operations have emerged as a key concept in shifting the focus from conventional building- (or system-) centric operations to a more occupant-centric approach. Despite the potential of OCC to meet occupants’ demands and bridge buildings’ energy performance gap, its implementation in real-world settings has been limited. In addition, there is a lack of standardization in methodologies and terms to facilitate meaningful comparisons among case studies. Therefore, this paper aims to present a repository of OCC case studies, offering a platform for standardization and presenting key information about practical implementations of these strategies in real-world scenarios. To …

Selective Production Of Levoglucosan (Lg) From Pyrolysis Of Date Pits And Its Catalytic Transformation Into Transportation Fuels, Ala Hamid Higazi

Theses

Levoglucosan (LG) or (1,6-anhydro-β-D-glucopyranose) signifies important sugar derivatives produces in appreciable quantities from thermochemical and biochemical degradation of biomass. It is often regarded as an important platform chemical for the synthesis of value-added products, most notably styrene and furans. The work in this thesis entails two broad aims; to produce LG from pyrolysis of date pits; and then convert the LG into transportation fuels through a hydrodeoxygenation (HDO) reaction. The particular choice of date pits stems from its local relative abundance as a waste biomass. Aiming to further improve the yield of levoglucosan yields from pyrolysis of date pits, pre-treatment …

Remote Side-Channel Disassembly On Field-Programmable Gate Arrays, Brandon R. Baggett

Graduate Theses and Dissertations (2019 - present)

Over the last two decades, side-channel vulnerabilities have shown to be a major threat to embedded devices. Most side-channel research has developed our understanding of the vulnerabilities to cryptographic devices due to their implementation and how we can protect them. However, side-channel leakage can yield useful information about many other processes that run on the device. One promising area that has received little attention is the side-channel leakage due to the execution of assembly instructions. There has been some work in this area that has demonstrated the idea’s potential, but so far, this research has assumed the adversary has physical …