A Primal Treatise Of Constant-Force Compliant Segment And Mechanism Design With Applications, Vamsi Lodagala

Doctoral Dissertations

"The evolution of compliant mechanisms propelled the development of constant-force mechanisms (CFMs) for various applications because of their unique characteristics. Many research endeavors have presented different techniques that often involve some optimization to design the CFMs. However, the mechanics of the generation of constant force at the elemental level is not well understood. This research effort theorizes and validates that simple, compliant segment with different boundary conditions, subjected to axial loading, produce near-constant force without the need for design optimization. Analytical models are developed based on the pseudo-rigid-body model (PRBM) concept to predict their force-displacement behavior, and to establish that …

Intragranular Tungsten-Titanium Carbide Composite Ceramics Via Gas-Solid Displacement Reactions, Ryan Daniel Dempsey

Doctoral Dissertations

"Research presented herein details the synthesis and characterization of nanocomposite ceramics featuring novel heterogeneous microstructures of potential interest in a variety of electrical and structural applications. Specifically, W-TiCy composite ceramics featuring tungsten nanoprecipitates located primarily within TiCy grains have been produced via sintering of intragranular nanocomposite powders produced via reaction processing-based techniques. This dissertation details the thermodynamic basis and applied kinetics of a processing scheme for fabricating nanocomposite ceramics whose morphological heterogeneity reflects that originally developed in the powder state. The first study in this series overviews the motivation for applying metallothermic displacement reactions, conducted through gaseous intermediates, to solid …

Effects Of Downwash When Measuring Gas Concentration With Uav-Mounted Gas Sensors, Jacob Lane Brinkman

Doctoral Dissertations

"This research concludes that the downwash region of a rotary-wing unmanned aerial vehicle (UAV) does not produce pressure variations substantial enough to cause significant changes in density-based gas concentration measurements. US regulations evaluate gas concentration as a function of gas density, and accurate concentration measurements are critical for protecting health and safety, which means evaluation of actual downwash effects on measured gas concentration is essential.

During experimentation, the UAV was fixed to a stand in a sealed chamber filled with NOx (NO and NO₂) of constant concentration. The UAV rotors ran at hovering speeds, and gas concentrations were …

Fiber Optic Sensors For Liquid Identifications, Wassana Naku

Doctoral Dissertations

"The fiber optic Fabry-Perot interferometer (FPI) is a widely utilized sensing configuration, offering numerous advantages over conventional electronic sensors, including high accuracy, distributed sensing capabilities, immunity to electromagnetic interference, and compact size. In this study, we propose a remarkably simple fiber optic-tip sensor system combined with machine learning techniques for the identification of pure and volatile organic liquids (VOLs).

A liquid droplet forms an extrinsic FPI (EFPI), with its effective reflectance being a function of the droplet's length. As the droplet evaporates, its length decreases. We conducted immersion tests using optical fiber tip sensors and monitored the time-transient responses of …

Phosphate And Borophosphate Glasses For Optical And Biomedical Applications, Parker Tracy Freudenberger

Doctoral Dissertations

"The goal of this work was to connect the network structures of phosphate and borophosphate glasses to the compositional dependence of properties related to biomedical applications. The glasses were characterized by a variety of techniques, including phosphate ion chromatography, Raman spectroscopy, and ¹¹B and ³¹P Magic Angle Spinning Nuclear Magnetic Resonance spectroscopy, which provide qualitative and quantitative information about the phosphate and borate moieties that constitute the network structures. The systematic addition of borate to a phosphate glass initially creates tetrahedral borate sites that replace P-O-P linkages with B-O-P linkages, and the properties of the resulting borophosphate glasses …

Application Of Modeling Methodologies To Improve An Emergency Departments Workflow, Prachita Humane

Doctoral Dissertations

"The healthcare system in the United States is complex and challenging to understand, and the emergency department (ED) serves as a bridge between outpatient and inpatient care. According to the Centers for Disease Control and Prevention, over 130 million people visited emergency rooms in the United States in 2018. The ED is composed of multiple subunits and components that make it difficult to comprehend fully. In this study, a combination of engineering analysis methods was used to identify and understand the issues in the ED.

The first contribution of this research involved collecting data through job shadowing of human entities …

Investigation Of Recrosslinkable Preformed Particle Gels For Natural Gas Conformance Control, Ali Abdulmohsen Al Brahim

Doctoral Dissertations

"Recross linkable Preformed Particle Gel (RPPG) is a novel type of preformed particle gel in which particles can bond together to form a strong bulk gel system after being placed in the target formation. In this research, I systematically evaluated the feasibility of using this product to improve gas flooding conformance for mature reservoirs with conduits or fractures. Two RPPG systems were used for the experiment: a CO₂- resistant RPPG (CR-RPPG) synthesized using acrylamide (AM) and 2-acrylamide-2- methylpropane sulfonate acid (AMPS), designed for CO2 flooding; and an acrylamide-co-acrylic acid-based RPPG (LT-RPPG), designed for water flooding. Different experimental apparatuses …

Sustainable Development: A Data Analysis Investigation For A New Conceptual Model, Case Study Comparison And Validation Techniques, Tiffanie Marie Toles

Doctoral Dissertations

"The three pillars model for sustainability, often represented with three intersecting circles described as economic, environmental, and social factors with sustainability being at the center is a complex and philosophically open model [1]. As society promotes efforts to reduce carbon impacts, there becomes a need to critically review the models employed for understanding. This research presents a validated methodology, an updated conceptual configuration of sustainability for overall use, as well as a sustainable development performance measurement system. Using the 2020 Sustainable Development Goals Index Data, 232 indicators from 193 countries were used to evaluate the efficacy of using more than …

Identification, Mapping, Analysis, And Dating Of Composite Mega Landslides In The Colorado Plateau, Conor Maris Watkins

Doctoral Dissertations

"This research consists of three articles focusing on landslide complexes within the Grand Canyon region of the Colorado Plateau. This is a vast and remote region of rugged topography. The landslide complexes in this study are greater than 10 million cubic meters in volume. The slides are located within different areas of the region and consist of differing geology but share multiple commonalities. Stratigraphic and structural controls tend to dictate where the slides occur. All of the landslides occur where carbonates and/or sandstones overlie over consolidated shales. The shales are susceptible to creep and strain softening where lateral confinement has …

Unsteady Flow Behaviors Generated By Three-Dimensional Lattice Geometries As Measured By Laser Doppler Velocimetry, Yi Qiao

Doctoral Dissertations

"The relation between flow stream turbulence and heat transfer has been known for a long time, that the heat transfer rate is increased if the turbulence or fluctuation level of the flow increases. Open cell foams and compact heat exchangers are two of the most common models applied for heat transfer augmentation. However, the small ligaments of open cell foams limit the heat conducted and smooth passages in compact heat exchangers cannot cause flow unsteadiness. Accordingly, new geometric models are needed to improve the heat transfer enhancement. Three-dimensional (3D) lattice geometries with a range of features and sizes can be …

Co2-Assisted Ethylene Production And Subsequent Purification: A Materials Development, Kinetic Assessment, And Process Performance Investigation, Khaled Baamran

Doctoral Dissertations

"This research focuses on the In-Situ CO₂ capture and utilization in the oxidative dehydrogenation of ethane (ODHE) for ethylene production, and a subsequent ethylene purification through adsorptive separation process. In particular, several dual-function materials (DFMs) were developed, formulated into 3D-structure, and investigated for ODHE reaction to ethylene under various process conditions using CO₂ as a mild oxidant. The DFMs materials were consisted of CaO and metal oxides (e.g., Cr₂O₃ and V₂O₅) supporting H-ZSM-5. The results indicated that higher cell densities lead to better performance due to kinetic enhancement, and the optimum …

Data Analytics Of Wettability Alteration With Surfactants In Carbonate Reservoirs, Ya Yao

Doctoral Dissertations

"Wettability alteration with surfactants has been widely applied to improve oil recovery in carbonate reservoirs. An effective surfactant huff-puff application design requires comprehensive guidelines about where, how, and when this method could be applied. Besides, traditional methods to design an effective application and optimize surfactant performance are dependent on extensive experiments and are time-consuming. This study is to assist in the design of surfactant huff-puff via statistical methods and machine learning techniques.

In this study, a dataset including 402 effective surfactant imbibition tests is established by collecting information from nearly 50 publications. The dataset provides a foundation for further data …

Design, Modeling And Analysis Of An Ac-Ac Dual Active Bridge Converter, Kartikeya Jayadurga Prasad Veeramraju

Doctoral Dissertations

"The Solid-State Transformer (SST) is gaining attention as an alternative to conventional iron-core transformers in the power electronic community. The power industry's increasing demands for smaller size, higher efficiency, and greater energy density have made the SST an attractive option. Among various power electronic converter topologies, the Dual Active Bridge (DAB) has become popular for its bidirectional power flow capability and galvanic isolation, primarily in the DC application space. Advancements in semiconductor technologies have introduced new bidirectional switches, opening avenues for novel SST topologies. This research investigates the application of the DAB as a single-stage SST and focuses on advancements …

Introduction Of A Variable Inductance Transformer For The Design Of Resonant Power Converters, Angshuman Sharma

Doctoral Dissertations

"Magnetic integration is a hot topic in power electronics that concerns the use of a transformer's leakage and magnetizing inductances purposefully in isolated power electronic converters, thereby giving the opportunity to save the cost and footprint of any additional inductor. This is of prime interest, especially in CLLLC resonant converters which require up to three inductors. For a complete integration of these inductances, the concept of a variable inductance transformer (VIT) is introduced in this thesis. A VIT is an adaptive magnetic structure that facilitates an easy adjustment of both magnetizing and leakage inductances to meet their desired values. However, …

Learning Representations For Novelty And Anomaly Detection, Ranya Almohsen

Graduate Theses, Dissertations, and Problem Reports (ETD)

The problem of novelty or anomaly detection refers to the ability to automatically

identify data samples that differ from a notion of normality. Techniques

that address this problem are necessary in many applications, like in medical

diagnosis, autonomous driving, fraud detection, or cyber-attack detection, just to

mention a few. The problem is inherently challenging because of the openness of

the space of distributions that characterize novelty or outlier data points. This is

often matched with the inability to adequately represent such distributions due

to the lack of representative data.

In this dissertation we address the challenge above by making several …

Environmental Controls Of Greenhouse Fluxes In Freshwater Wetlands Across The Globe, Samira Jahan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Freshwater wetlands can contribute significantly to the global carbon budget as a net source or sink of the major greenhouse gas (GHG) fluxes such as carbon dioxide (FCO₂) and methane (FCH₄). The amount of GHG fluxes in the freshwater wetlands is highly variable and depends on a range of environmental drivers. These wetlands are commonly hypothesized to be net sinks (i.e., burial) of FCO₂ and net sources (emission) of FCH₄ at the monthly to annual scales. Understanding the environmental controls on the wetland GHG fluxes is essential for an accurate estimation of the global …

Analysis Of The Root Causes Of Fatal Injuries In The United States Surface Mines Between 2008 And 2021., Maria Fernanda Quintero

Graduate Theses, Dissertations, and Problem Reports (ETD)

Mining has long been recognized as a hazardous industry worldwide. An annual average rate of 10.3 fatal injuries per 100,000 workers was recorded in the United States between 2008 and 2021 (MSHA, 2022). This rate can be compared with the average of the industries with the highest average rates of fatal injuries—agriculture, forestry, fishing, and hunting; transportation and warehousing; and construction—which had average rates of 23.5, 13.1, and 9.9 fatal injuries per 100,000 workers, respectively, during the same period in the Unites States (U.S. Bureau of Labor Statistics, 2023).

The scope of this research is related to the fatal injuries …

Evaluating Electrification Of Fossil Fuel-Fired Boilers For Decarbonization Using Discrete Event Simulation, Nahian Ismail Chowdhury

Graduate Theses, Dissertations, and Problem Reports (ETD)

Decarbonizing fossil fuel usage is crucial in mitigating the impacts of climate change. CO2, which comprises the major portion of greenhouse gas, is emitted from burning fossil fuels. One of the significant sources of fossil fuel user is industrial process heating, and most of the heating in industrial processes is achieved through boilers. Electrification is a promising solution for decarbonizing these boilers, as it enables renewable energy sources to generate electricity, which can then be used to power the electric boilers. The electrification of boilers can reduce greenhouse gas emissions, improve air quality, and increase energy efficiency. However, it requires …

Generative Adversarial Network And Its Application In Aerial Vehicle Detection And Biometric Identification System, Moktari Mostofa

Graduate Theses, Dissertations, and Problem Reports (ETD)

In recent years, generative adversarial networks (GANs) have shown great potential in advancing the state-of-the-art in many areas of computer vision, most notably in image synthesis and manipulation tasks. GAN is a generative model which simultaneously trains a generator and a discriminator in an adversarial manner to produce real-looking synthetic data by capturing the underlying data distribution. Due to its powerful ability to generate high-quality and visually pleasing
results, we apply it to super-resolution and image-to-image translation techniques to address vehicle detection in low-resolution aerial images and cross-spectral cross-resolution iris recognition. First, we develop a Multi-scale GAN (MsGAN) with multiple …

Development Of Machine Learning Based Approach To Predict Fuel Consumption And Maintenance Cost Of Heavy-Duty Vehicles Using Diesel And Alternative Fuels, Sasanka Katreddi

Graduate Theses, Dissertations, and Problem Reports (ETD)

One of the major contributors of human-made greenhouse gases (GHG) namely carbon dioxide (CO2), methane (CH4), and nitrous oxide (NOX) in the transportation sector and heavy-duty vehicles (HDV) contributing to about 27% of the overall fraction. In addition to the rapid increase in global temperature, airborne pollutants from diesel vehicles also present a risk to human health. Even a small improvement that could potentially drive energy savings to the century-old mature diesel technology could yield a significant impact on minimizing greenhouse gas emissions. With the increasing focus on reducing emissions and operating costs, there is a need for efficient and …

Nonlinear Dynamic Analysis And Control Of Chemical Processes Using Dynamic Operability, San Quan Dinh

Graduate Theses, Dissertations, and Problem Reports (ETD)

Nonlinear dynamic analysis serves an increasingly important role in process systems engineering research. Understanding the nonlinear dynamics from the mathematical model of a process helps to find the boundaries of all achievable process conditions and identify the system instabilities. The information on such boundaries is beneficial for optimizing the design and formulating a control structure. However, a systematic approach to analyzing nonlinear dynamics of chemical processes considering such boundaries in a quantifiable and adaptable way is yet to exist in the literature. The primary aim of this work is to formulate theoretical concepts for dynamic operability, as well as develop …

Optimal Path Planning For Aerial Robots Using Genetic Algorithm, Anna Puigvert I Juan

Graduate Theses, Dissertations, and Problem Reports (ETD)

This thesis presents a path optimization solution for a robot in two different constrained 3-dimensional (3D) environments. The robot is required to travel from its current position to a goal position following minimum cost paths (optimal paths). The first environment has 3D obstacles that interfere with the robot’s path. The path cost for this environment accounts for the minimum distance traveled by the robot from the start to the goal position while avoiding obstacles. The second environment is the atmosphere of Venus, specifically a flyable region of this atmosphere with characteristics similar to Earth’s. This environment has strong westward winds …

Dynamic Modeling, Data Reconciliation, Parameter Estimation, And Health Monitoring Of A Supercritical Power Plant, Katherine Grace Hedrick

Graduate Theses, Dissertations, and Problem Reports (ETD)

With the introduction of a larger portion of renewable sources of power coming onto the U.S. power grid in recent decades, the operational strategy of coal-fired power plants has changed significantly to focus more on flexibility in response to the changing energy market. This has naturally led to different operational challenges. Many of these challenges are focused on the boilers within these plants, as they are producing more emissions and experiencing increased damage during load-following, which in turn leads to increased costs from penalties for not achieving emission standards or maintenance costs as boilers accumulate damage from the cycling behavior. …

Computational Mechanisms Of Face Perception, Jinge Wang

Graduate Theses, Dissertations, and Problem Reports (ETD)

The intertwined history of artificial intelligence and neuroscience has significantly impacted their development, with AI arising from and evolving alongside neuroscience. The remarkable performance of deep learning has inspired neuroscientists to investigate and utilize artificial neural networks as computational models to address biological issues. Studying the brain and its operational mechanisms can greatly enhance our understanding of neural networks, which has crucial implications for developing efficient AI algorithms. Many of the advanced perceptual and cognitive skills of biological systems are now possible to achieve through artificial intelligence systems, which is transforming our knowledge of brain function. Thus, the need for …

Structural Health Monitoring Using Machine Learning And Synthetic Data, Michail Tzimas

Graduate Theses, Dissertations, and Problem Reports (ETD)

Structural health monitoring spans many decades of research across multiple engineering fields. However, typical monitoring processes for damage detection of complex structures usually prohibit real-time or fast detection of debilitating damage to the structure. One of the major issues of real-time detection of damage is the enormity of data that needs to be processed, which is worsened by the relative inability of fast relaying of data to structural engineers. With the rapid advancement of Machine Learning, both issues can be overcome, and detection of failure is achieved with non-invasive techniques. This dissertation explores the applicability of Machine Learning as a …

Modular Supply Network Optimization Of Renewable Ammonia And Methanol Co-Production, Benjamin Akoh

Graduate Theses, Dissertations, and Problem Reports (ETD)

To reduce the use of fossil fuels and other carbonaceous fuels, renewable energy sources such as solar, wind, geothermal energy have been suggested to be promising alternative energy that guarantee sustainable and clean environment. However, the availability of renewable energy has been limited due to its dependence on weather and geographical location. This challenge is intended to be solved by the utilization of the renewable energy in the production of chemical energy carriers. Hydrogen has been proposed as a potential renewable energy carrier, however, its chemical instability and high liquefaction energy makes researchers seek for other alternative energy carriers. Ammonia …

Investigating The Impact Of Demographic Factors On Contactless Fingerprint Interoperability, Aeddon David Berti

Graduate Theses, Dissertations, and Problem Reports (ETD)

Improvements in contactless fingerprinting have resulted in contactless fingerprints becoming a faster and more convenient alternative to contact fingerprints. The interoperability between contactless fingerprints and contact fingerprints and how demographic factors can change interoperability has been challenging since COVID-19; the need for hygienic alternatives has only grown because of the sudden focus during the pandemic. Past work has shown issues with the interoperability of contactless prints from kiosk devices and phone fingerprint collection apps. Demographic bias in photography for facial recognition could affect photographed fingerprints. The paper focuses on evaluating match performance between contact and contactless fingerprints and evaluating match …

Lithium-Ion Battery Safety Analysis With Physical Sub-Models, Samuel Abimbola Ogunfuye

Graduate Theses, Dissertations, and Problem Reports (ETD)

Ever-increasing explosions occurring globally at a rapid rate and in diverse situations have re-established the fact that novel, faster, and more accurate approaches must be developed to analyze and possibly curb these explosions and avert their future occurrences. Experimental endeavors and computational fluid dynamics (CFD) simulations as compared to engineering models generally require enormous time, and resources, as well as a high-level of expertise and technicalities. This might, however, delay prompt analysis and the ability to draw conclusions, thereby causing setbacks in recommending safety measures for different situations and conditions. Therefore, robust models which are accurate and fast to give …

Augmented Reality And Mobile Systems For Heavy Equipment Operators In Surface Mining, Juan David Valencia Quiceno

Graduate Theses, Dissertations, and Problem Reports (ETD)

U.S. federal laws mandate that mining companies ensure a safe workplace, implement approved training programs, and promptly report work-related injuries. The mining industry's commitment to innovation reflects a history of adopting advancements to enhance environmental sustainability, workplace safety, and overall productivity, while simultaneously reducing operational costs. This thesis proposes the integration of Augmented Reality (AR) technology and digital applications to enhance the surface mining industry, presenting two innovative solutions: an AR Training System and an Operational Digital System. These business solutions have been developed and applied at a surface mine in the southwest of the US, having the potential to …

Longitudinal Oxygen Imaging In 3d (Bio)Printed Models, Ryan Curtis O'Connell

Graduate Theses, Dissertations, and Problem Reports (ETD)

Electron paramagnetic resonance (EPR), and its molecular imaging modality, is a powerful tool to noninvasively map various biological and chemical markers within objects of interest. Reliable data acquisition is a major impeding factor for longitudinal hands-off measurements. Measurements are especially challenging in biomedical applications, as live objects are not static. Frequent changes occur that require constant fine recalibration of the EPR detection system, called the resonator. To enable longitudinal imaging, a technology permitting automatic digital control of resonator coupling, tuning, and EPR data acquisition was developed. Automation was achieved through the utilization of a microcontroller and digital peripheral components such …