Digital Commons Network^™

Measurement And Simulation Of Aeroacoustic Sources Generated By Elementary Muffler Components, Seth Donkin

Theses and Dissertations--Mechanical and Aerospace Engineering

Mufflers and silencers are commonly used to control noise from sources such as internal combustion engines and heating, ventilating, and air conditioning (HVAC) systems. In these applications, flow interacts with muffler components generating aeroacoustic noise sources. In order to measure these sources in a lab setting, specialized flow rigs are designed to isolate aeroacoustic noise sources. Flow sometimes compromises muffler performance. However, muffler performance is sometimes improved because flow can increase the attenuation of some muffler elements such as perforates. To better understand the complicated impact of flow, the University of Kentucky developed a muffler test rig to measure insertion …

Droplet Analysis Of Spray Inside A Compact Column Gas Scrubber Through Shadowgraphy, Brandon Heller

Theses and Dissertations--Mechanical and Aerospace Engineering

The shadowgraphy imaging technique was adapted to analyze the droplet field from a spray nozzle inside the gas absorption section of a compact column gas scrubber. This technique in conjunction with a developed image processing technique was able to gain statistical size information at different distances from two types of spray nozzles. The gas scrubber then ran a parametric campaign of eight operating conditions and statistical size information was captured for each case with the goal of understanding how operating conditions affect the droplet field properties. Lastly, several simulations were completed to understand how the addition of recirculation zones would …

Microstructure-Based Modeling And Simulation Via A Nonlocal Multiphysics Discrete Approach, Donglai Liu

Theses and Dissertations--Mechanical and Aerospace Engineering

Many structures in engineering are subject to multiphysics loadings or environment. Computational modeling plays a significant role to predict or evaluate the performance of these structures, especially in the scenarios where the experimental investigation is cumbersome or prohibitively expensive. Microstructure-based modeling incorporates the information of microstructures of materials in numerical models, which can provide insights about the relationship between microstructures and mate- rial properties. This research developed a microstructure-based modeling framework for coupling diffusion-deformation simulation of solids. The model is based on a recent developed meshfree method referred to as lattice particle method in the literature. In the developed model, …

Mechanochemical Synthesis Of Halide Perovskite Microcrystals, Xuan Huang

Theses and Dissertations--Mechanical and Aerospace Engineering

Halide perovskites have emerged as a promising class of materials for various optoelectronic applications, including light-emitting diodes (LEDs), solar cells, photodetectors, and lasers, owing to their exceptional photophysical properties and ease of synthesis. Lead-based halide perovskites, despite their success, raise concerns regarding environmental toxicity, necessitating the exploration of lead-free alternatives. This thesis explores the synthesis and characterization of lead-free halide perovskites, focusing on tin-based variants, using a mechanochemical approach, which eliminates the use of toxic solvents and offers a sustainable synthesis route.

By employing a solventless mechanochemical method, lead-free tin-based halide perovskite microcrystals were successfully synthesized. This approach not only …

Provably Safe Control For Input-Constrained Robotic Systems, Pedram Rabiee

Theses and Dissertations--Mechanical and Aerospace Engineering

This dissertation addresses challenges in control design for safety-critical robotic systems with input constraints. It focuses on developing novel control barrier function (CBF) approaches to ensure safety while optimizing performance. The work is motivated by the limitations of traditional methods in handling nonlinear systems with multiple constraints and actuator limits.

Three main contributions are presented. First, a soft-minimum barrier function is introduced, utilizing finite-time horizon predictions to create control forward invariant subsets of the safe set while respecting actuator constraints. This method is extended to multiple backup controls, which can enlarge the safe operating region.

Second, a technique for composing …

High-Fidelity Coupling For Studies Of Ablative Materials At Hypersonic Conditions, Aleksander Zibitsker

Theses and Dissertations--Mechanical and Aerospace Engineering

The development of accurate models and robust numerical tools for simulating ablative thermal protection materials (TPMs) in hypersonic flows is crucial for advancing atmospheric entry and hypersonic technologies. Traditional methods for simulating ablative materials often rely on heavy assumptions, such as equal heat and mass transfer coefficients and chemical equilibrium in the boundary layer, leading to conservative thermal protection system (TPS) designs and insufficient accuracy for certain in-flight ablation phenomena.

This work presents a high-fidelity and versatile coupled framework between hypersonic flow and material response solvers. The flow domain is modeled with an innovative overset CHAMPS NBS-Cart solver, which features …

Multiscale Fiber Remodeling In The Heart Using A Finite Element Framework, Mohammad Mehri

Theses and Dissertations--Mechanical and Aerospace Engineering

The organization of myofibers and extra cellular matrix within the myocardium plays a significant role in defining cardiac function. When pathological events occur, such as myocardial infarction (MI) or hypertrophic cardiomyopathy (HCM), this organization can become disrupted, leading to alteration in pumping performance. The current study proposes a multiscale finite element (FE) framework to determine realistic fiber distributions in the left ventricle (LV). This is achieved by implementing a stress-based fiber reorientation law, which seeks to align the fibers with local traction vectors, such that contractile force and load bearing capabilities are maximized. By utilizing the total stress (passive and …

Characterization Of Heterogeneous Material Architectures Through X-Ray Computed Micro-Tomography, Cameron Brewer

Theses and Dissertations--Mechanical and Aerospace Engineering

Low-density carbon-phenolic composites, such as phenolic impregnated carbon ablator (PICA), possess meso-, micro-, and nano-pores making the structure of the resin difficult to characterize. X-ray Computed Tomography (XRCT) is a widely ac- cepted method for characterizing the carbon fiber preform, yet this technique is often insufficient for visualizing the resin because of its minimal attenuation of the incident x-ray beam. Phase Contrast Retrieval (PCR) reconstruction considers not only the linear attenuation coefficient, but also the refractive indices of the constituent materials. This research leverages phase contrast tomography to characterize the meso- and micro-structure of the porous resin phase with a …

Repolarizing Tumor-Associated Macrophages In Ovarian Cancer: A Novel Immunotherapeutic Approach, David Schweer

Theses and Dissertations--Clinical and Translational Science

Ovarian cancer, recognized for its high lethality and resistance to conventional immunotherapies, mandates innovative strategies to confront its intricate challenges. The tumor microenvironment (TME), orchestrated by tumor-associated macrophages (TAMs), assumes a pivotal role in disease progression, rendering TAMs an appealing therapeutic target. This study endeavors to explore the prospect of repolarizing TAMs from a protumor M2 phenotype to an antitumor M1 state, employing M1 macrophage-derived vesicles (MEVs) as a groundbreaking immunotherapeutic approach.

The primary objective is to investigate the capacity of M1 MEVs to repolarize M2 macrophages in vitro towards an anti-tumor M1-like phenotype. By inducing human macrophages to adopt …

Abl1/2 And Ddr1 Cooperate To Stabilize Braf/Craf To Drive Erk1/2 Reactivation And Promote Mek Inhibitor Resistance In Nras-Mutant Melanomas, Anastasia Lyon

Theses and Dissertations--Pharmacology and Nutritional Sciences

This study addresses the escalating incidence of NRAS-mutant melanomas, a type of skin cancer lacking FDA-approved targeted therapies. Despite ongoing research targeting the RAF/MEK/ERK pathway, existing drugs fail to enhance progression-free survival due to acquired resistance. This project identifies a novel role for ABL1/2 and DDR1 kinases in driving drug resistance and proliferation of NRAS-mutant melanoma cells. ABL1/2 and DDR1 cooperate to promote RAF homodimerization and protein stability in order to reactivate MEK/ERK signaling to drive MEK1/2 inhibitor (MEKi) resistance and promote survival of resistant cells. By targeting ABL1/2 and DDR1 with nilotinib, a FDA-approved anti-leukemic inhibitor, we …

Mitigating Risks For Dementia In Apoe4 Mice: Efficacy Of Prebiotic Inulin, Probiotics, And Fecal Microbiota Transplants, Ya-Hsuan Chang

Theses and Dissertations--Pharmacology and Nutritional Sciences

Apolipoprotein E4 allele (APOE4) carriers show early metabolic changes, heightening the genetic risk of late-onset Alzheimer's Disease (AD), characterized by amyloid-β and tau tangle plaques and neurodegeneration. Its development is influenced by age, environment, and genetics, with Mild Cognitive Impairment (MCI) often preceding AD, providing a crucial window for early intervention. Factors in AD progression include sex differences and gut microbiome imbalances, with women disproportionately affected and APOE4 carriers showing early metabolic and cognitive changes. This study explores the potential of prebiotic inulin, probiotic Bifidobacterium animalis, and fecal microbiota transplants (FMT) from healthy donors to mitigate AD …

Practical Challenges In Delivering Dsrna For Woody Plant Protection, Zachary Bragg

Theses and Dissertations--Entomology

Unprecedented weather events associated with climate change, coupled with extensive anthropogenic stresses, have reduced the effectiveness of traditional forest pest management approaches, which can no longer keep pace with invasive species overwhelming naïve landscapes and native pests experiencing eruptive and expansive outbreaks. Double-stranded RNA-(dsRNA) mediated gene silencing, a type of RNA interference (RNAi), has been coopted for use as a biopesticide against a multitude of agricultural and horticultural pests and could serve as a powerful tool for woody plant protection. While effective initiation of gene silencing and subsequent mortality have been demonstrated in multiple tree pests, effective and efficient methods …

Consequences Of Abiotic And Anthropogenic Stressors In The Antarctic Midge, Belgica Antarctica, Jack J. Devlin

Theses and Dissertations--Entomology

The ability to tolerate stress is key to maintaining fitness in extreme environments such as the polar regions. Subject to a myriad of extreme year-round abiotic conditions, invertebrates inhabiting the terrestrial ecosystems of Antarctica provide an excellent system to investigate adaptations to stress. Understanding the response of these species to abiotic and novel stressors is crucial in a world with rapidly occurring climate change and increasing anthropogenic activity. In this dissertation, I investigated physiological and molecular responses to naturally occurring and human-derived stresses in the midge Belgica antarctica, which is Antarctica’s only endemic insect.

In my first research chapter, I …

Malleability Of Abortion Attitudes, Allison Leip

Theses and Dissertations--Family Sciences

Although abortion attitudes have been thoroughly investigated and population-level attitudes have not changed much over the past half-century, polls and research inquiring about abortion attitudes tend to ask isolated questions about if, and in what circumstances, abortion should be legal. The purpose of this study was to examine the extent to which abortion attitudes both varied and changed according to several contextual factors. A multiple-segment factorial vignette was conducted with 530 respondents in the state of Kentucky. Overall, most respondents held strong attitudes on access to abortion, both before the rationale was provided and regardless of the rationale provided. However, …

Manrrs Advisors And Their Perceptions Of Their Mentor Strategies, Dallas L. Cooks

Theses and Dissertations--Community & Leadership Development

Minorities in Agriculture Natural Resources and Related Sciences, also known as MANRRS, is an organization with chapters nationwide. Their main focus is to provide professional development, academic advancement, and networking to those in agriculture and related sciences. This research focuses on the advisors of MANRRS chapters across the country and at various institutions. Advisors were asked a series of questions through a Qualtrics survey about their mentor strategies with their students. Chapter Advisors were asked demographic, Likert Scale, and questions based on their personal MANRRS experience. As a result of the data, five research questions were answered. Chapter Advisors and …

"We Are The Mycelium" Exploring Mutual Aid Networks And Food System Resilience In Eastern Kentucky, Lindsey A. Windland

Theses and Dissertations--Community & Leadership Development

The effects of climate change are predicted to have a widespread impact on numerous aspects of the U.S. food system. Industrialization and consolidation within the U.S. food system have decreased the food system’s capacity for adaptation to external stressors. In recent years local food systems have demonstrated a potential for adaptation during and after disasters. More research is needed to better understand local food systems and their adaptative innovations, as a better understanding of these innovations is important for developing local food systems with strong adaptative capacities. This exploratory study examines how the local food systems of Eastern Kentucky pivoted …

Autism In Agricultural Education: A Case Study Of An Adolescent With Autism Spectrum Disorder And Their Parent On Career And Technical Education, Grace Miller

Theses and Dissertations--Community & Leadership Development

Autism spectrum disorder (ASD) is a unique and often misunderstood diagnosis. Little is known about the experiences of adolescents with ASD. As students with ASD graduate high school, many are under- and unemployed. Career and technical education (CTE) in U.S. schools is intended to prepare all students for careers post-secondary. Agricultural education is one of the predominate career clusters within CTE. This qualitative single case study sought to create a platform for both a student and their parent to share their experiences in agricultural education and CTE. Participants were an adolescent with ASD who had taken at least one year …

Development Of Lignin Derived Hydrophobic Deep Eutectic Solvents As Sustainable Solvents And Their Applications, Yuxuan Zhang

Theses and Dissertations--Biosystems and Agricultural Engineering

The development of green solvents is a pivotal endeavor in achieving the goals of green chemistry. Ionic liquids (ILs) and deep eutectic solvents (DESs) have emerged as promising green alternatives to conventional organic solvents due to their low toxicity, potential biodegradability, low volatility, and high tunability. Compared to ILs, DESs have attracted more attention recently as they are easier and less expensive to produce. Hydrophobic DESs (HDESs), a new generation of DESs introduced in 2015, have gained considerable interest for their ability to overcome the instability issues of traditional DESs when exposed to water. This advancement extensively broadens the application …

Implications Of Nanopesticides On Downstream Wetland Ecosystems, Kiley Power

Theses and Dissertations--Biosystems and Agricultural Engineering

Nanopesticides are thought to be a promising course of action for reducing agricultural impacts on the environment, however, little is known regarding the fate and transport of nanopesticides, specifically their influence on downstream wetland ecosystems. The objective of this study was to assess the implications of a nano-Cu fungicide (Kocide 3000) and a neonicotinoid insecticide (imidacloprid) on downstream wetland habitats, particularly their effects on wetland nutrient cycling, using fifteen mesocosm wetlands. The complex interactions between nitrogen, Kocide 3000, and imidacloprid were found to increase nitrate removal rates, decrease phosphate removal rates, and inhibit nitrogen uptake in below-ground biomass. Each treatment, …

The Characterization, Assessment, And Shear Strength Of Turfgrass Soil In North American Thoroughbred Racing, Peter Schmitt

Theses and Dissertations--Biosystems and Agricultural Engineering

Minimizing catastrophic injuries to racehorses, which also protects the riders, is critical for the future of the Thoroughbred racing industry. While the causes of catastrophic injuries are multifactorial, the condition of the racing surface is one of only a few factors that affects all horses in competition. Horse racing surfaces must retain enough shear strength to support the hoof of a Thoroughbred at a gallop. Turfgrass racing surfaces also require healthy turf to reinforce the footing while also achieving a high infiltration rate to allow races to run on the turf soon after or even during rain. This research is …

Wetland Treatment Systems For Municipal Wastewater At A Bourbon Distillery And Potential Value Of Incorporating Stillage For Water Treatment Enhancement, Katherine J. Ristola

Theses and Dissertations--Biosystems and Agricultural Engineering

The use of constructed treatment wetlands, as a secondary treatment method for wastewater effluent from package treatment plants and distillery stillage has potential to be an innovative, sustainable method for improving water quality in the Central Kentucky region. However, the use of constructed wetlands to treat stillage and wastewater treatment plant effluent has been limited. Therefore, the objectives of this study were to: 1) quantify constructed wetland removal as a secondary treatment method for distillery’s wastewater; 2) explore the potential to utilize constructed treatment wetlands to remove nutrients from bourbon stillage; and 3) optimize treatment design to meet wastewater effluent …

Utilizing Isotope Tracing To Assess Land Use Implications To Tap And Stream Water Chemistry, Katrina Alexis Mcfadden

Theses and Dissertations--Biosystems and Agricultural Engineering

Water quality is an issue that continues to be worsened by extreme flooding, specifically in Eastern Kentucky. The most recent 2022 flooding event in Eastern Kentucky resulted in loss of human life, over $23.3 billion in damaged infrastructure, and impaired human health. Infrastructure failures, such as leaky pipes, are a growing challenge in these regions as rebuilding has occurred. Therefore, the goal of this project was to evaluate water quality in two of the counties most impacted by the 2022 flood in Kentucky, Breathitt and Perry Counties, using sulfur isotopes as a novel tracer to identify potentially failures in distribution …

The Efficacy Of Wetland Treatment Systems Used To Treat Runoff Mixtures From Different Landscapes Across Kentucky, Emily Nottingham

Theses and Dissertations--Biosystems and Agricultural Engineering

The overarching goal was to improve our understanding of the cumulative effect of increased use and occurrence of commonly detected contaminants of potential concern (CPCs) on nitrogen (N) transformation processes in wetlands. The central hypothesis was that those various mixtures of nutrients and CPCs entering treatment wetlands impact N removal pathways. The first study assessed the current state of the literature on the implications to N removal in wetlands in the presence of pesticides and antibiotics. 181 primary studies were identified. Removal efficiencies for nitrate varied widely across the studies, with CPCs impacting microbial communities. A knowledge gap remains in …

Valorization Of Bourbon Distilling Waste Using Thermal Conversion Processes For Nutrient-Rich Food Products, Tosin Olayemi Olanrewaju

Theses and Dissertations--Biosystems and Agricultural Engineering

The Commonwealth of Kentucky accounts for over 95% of global bourbon production. A primary byproduct of bourbon production is stillage, which has a very high moisture content (91–94%) and high biochemical oxygen demand, making it challenging to manage. The recent expansion of the bourbon industry has heightened environmental concerns regarding the best methods to handle this byproduct. Dewatering and drying of stillage produce distillers' spent grains (DSG-B), which are rich in dietary fiber and protein and could serve as an excellent source of functional fiber in human nutrition.

This study examined the approach for dewatering, drying, inclusion of DSG-B as …

Respiranalyzer, Teng Zhang, Xinzheng Dong, Dandan Wang, Chen Huang, Xiaohua Douglas Zhang

Biostatistics Faculty Publications

Motivation: The analysis of data obtained from continuous monitoring of respiratory signals (CMRS) holds significant importance in improving patient care, optimizing sports performance, and advancing scientific understanding in the field of respiratory health. Results: The R package RespirAnalyzer provides an analytic tool specifically for feature extraction, fractal and complexity analysis for CMRS data. The package covers a wide and comprehensive range of data analysis methods including obtaining inter-breath intervals (IBI) series, plotting time series, obtaining summary statistics of IBI series, conducting power spectral density, multifractal detrended fluctuation analysis (MFDFA) and multiscale sample entropy analysis, fitting the MFDFA results with the …

Developing Best Practices For Successful University Fundraising Events, Ravyn Ladenburger

MPA/MPP/MPFM Capstone Projects

This research study addresses the crucial role of fundraising in sustaining universities in the United States, particularly public institutions facing funding challenges. For this paper, fundraising refers to the seeking of financial support from individuals to support initiatives at a nonprofit entity, such as a public university. It identifies a gap in research and professionalization within higher education philanthropy, emphasizing the need for standardized training and empirical research. The focus is on studying the effectiveness of fundraising events, especially in public universities like the University of Kentucky, amidst declining government support and rising operational costs. The research problem to be …

A Review Of The Individuals With Disabilities Education Act In Kentucky Schools System, Spencer Collins

MPA/MPP/MPFM Capstone Projects

The federal government's role in education has been center stage for the past decade. Policy actors on the right call for a complete deconstruction of the federal Department of Education (ED). In today's partisan fighting over government funding, the topic of education services is critical. With further investigations into education services provided by federal funding, one vulnerable population that needs to be safeguarded is those students with disabilities. Protecting those students with disabilities and ensuring equal access to education and resources provided for non-disabled students should be one of the highest priorities of policy actors within the education sphere today. …

Relationship Between Weir Openings And Green Tide Variation In Korean Rivers, Uisuk Jung

MPA/MPP/MPFM Capstone Projects

On the four major rivers in South Korea (Han River, Nakdong River, Geum River, and Yeongsan River), 16 weirs were installed in 2011 to secure water resources. However, there is controversy that the weirs allow the summer Green Tide (hereafter referred to as GT) to thrive, so the South Korean government has been opening them since 2017 to evaluate their effectiveness. The opening of the weirs was mainly done at three weirs on the Geum River, where there are few constraints, and some on the Yeongsan and Nakdong rivers, depending on the degree of constraints, while the Han River was …

Enhancing Equity And Economic Growth: A Strategic Review Of Procurement Practices In Prince George’S County, Andrew Stover

MPA/MPP/MPFM Capstone Projects

Procurement represents a substantial portion of public spending in state and local governments, and thus is an essential element of responsible public financial management. This paper explores the procurement process on the local government level and provides research into best practices that are conducive to equity and economic development. It takes a look specifically at Prince George’s County, Maryland and analyzes its procurement function in relation to these best practices. An analysis of the County finds that despite its strides in implementing equitable procurement policies, significant gaps remain in the engagement of disadvantaged classes of businesses. To tackle these challenges, …

The Fairness Model Of Legal Institutions, James M. Donovan

Law Faculty Books and Chapters

If any group is to endure over time, individual frustrations, while inevitable, must be usually experienced as acceptable, or at least tolerable. Failing that, little would prevent the losers in these conflicts from leaving or revolting, which would be cumulatively debilitating to the group. As opposed to holding law’s job to impose order and police infringers, the second approach suggests that finding the balance between group and individual desires is the ‘major difficulty of all law—the problem of really getting a fresh start in relations between litigants after disposition of a trouble-case. This is the problem not only of keeping …