Digital Commons Network^™

Experimental And Numerical Studies Of Laser Powder-Bed Fusion Process With Ti-6al-4v Powder: (1) Porosity And Mechanical Properties, And (2) Transient Phenomena In One- And Two-Dimensional Fabrications., Santosh K. Rauniyar

Electronic Theses and Dissertations

Laser powder bed fusion (L-PBF) process represents a form of metal additive manufacturing (AM) where micron-level powdered material is selectively melted and fused layer by layer to create intricate three-dimensional parts. This process involves rapid melting and solidification, leading to intense thermocapillary convection within the molten pool. The melt pool is a crucial element of the L-PBF process and refers to the localized region where the powder particles are melted and solidified to form each layer of the printed part. The shape and dimensions of the melt pool directly influence the accuracy and surface finish of the printed part. Precise …

The Role Of E-Liquid Constituents In E-Cigarette-Induced Cardiac Arrhythmia And Autonomic Imbalance., Cory Kucera

Electronic Theses and Dissertations

Introduction. Accumulating evidence indicates that exposure to electronic cigarettes (e-cigs) promotes sympathetic dominance and electrophysiologic instability in the heart, potentially culminating in arrhythmogenesis. E-liquids contain various formulations of nicotine and flavorings, but the effects of specific e-liquid constituents and their concentrations on e-cig-induced autonomic imbalance and electrical dysfunction are unresolved. To that end, we tested the hypothesis that e-cigs modify cardiac autonomic balance and ventricular arrhythmogenesis in mice dependent on e-liquid constituent type and concentration. Methods. Using a crossover design and a serial exposure regimen, ECG-telemetered male C57BL/6J mice underwent whole-body exposure to e-cig aerosols generated from e-liquids containing different …

Using Graphic Novels To Teach Economics Content To High School Students With Extensive Support Needs., Caroline Mae Fitchett

Electronic Theses and Dissertations

The purpose of social studies instruction in school is to facilitate the growth of competent citizens (National Council for the Social Studies [NCSS], 2013). Despite the recognized benefit of social studies instruction, emphasis on this subject has decreased over time, and has ultimately been termed a “dispensable subject” (Fitchett & Haefner, 2010). Social studies is an even more marginalized subject area for students with disabilities (Zakas et al., 2013). Expanding the research in this area is not only necessary to improving social studies academic content acquisition but is also likely to facilitate greater independence for students post-school – and by …

Principal Supervisor Professional Learning In A Community Of Practice., Jessica Rosenthal

Electronic Theses and Dissertations

Principal supervisor professional learning is an area of educational professionalism that is under-researched and under-developed (Casserly et al., 2013). Because K-12 students deserve to have the best leaders possible impacting their school experience, K-12 principal supervisors need professional learning that strengthens their ability to coach and evaluate K-12 principals (Waters & Marzano, 2006). This study utilized a principal supervisor community of practice as a form of role-specific professional learning. Semi-structured interviews occurring before and after four community of practice convenings along with transcripts from the convenings were used to answer questions that explored principal supervisors’ characterization of a community of …

Changes To Water Quality And Discharge In An Urban Stream In Southwest Jefferson County., Karina Henson

Electronic Theses and Dissertations

Mill Creek is the largest watershed in Southwest Jefferson County, where thousands of people live and work. Streams in the watershed have historically been channelized and altered to promote drainage, and stream health is of major concern. Louisville MSD is currently developing a watershed plan for Mill Creek by seeking understanding of current stream conditions. This paper will focus on historical trends in stream discharge and water quality. Peak and daily discharge, dissolved oxygen, specific conductance, and temperature data from USGS gages at Mill Creek and the Mill Creek Cutoff was analyzed to understand how water quality and flow rates …

“Difference In/At The Center" A Transnational Approach For Mobilizing International Multilingual Graduate Writers' Writing Assets During Writing Instruction., Olalekan Adepoju

Electronic Theses and Dissertations

This research project presents an empirical exploration of how the writing assets possessed by international multilingual graduate writers impact the theory and pedagogical practices in writing studies, especially regarding the approaches to teaching writing. Extant scholarship in writing studies, especially on second language research/teaching, translingual writing practices, and asset-based writing pedagogy has engaged issues of difference in language, race, culture, as well as funds of knowledge, highlighting the impacts of these differences on the academic success of non-native English speakers in US schools and colleges. My dissertation builds on these trends and highlights the narratives, perceptions, and experiences of international …

From Androgyny To Binary And Back: A Qualitative Analysis Of Nonbinary Tiktoks., Savannah Hatton

Electronic Theses and Dissertations

This study explores how nonbinary individuals represent and express their gender on TikTok. Given the limited amount of research that has been done on nonbinary gender expression in online spaces, this study uses TikTok to observe the ways that nonbinary individuals perform gender. Additionally, given the relative newness of TikTok, this study serves to inform growing research on identity formation through social media. It used a sample of fifty TikToks by nonbinary creators to perform a content analysis. The findings reveal significant variation in how nonbinary individuals "do gender" on the platform, with some individuals identifying closely with binary labels, …

Cannabidiol Tweet Miner: A Framework For Identifying Misinformation In Cbd Tweets., Jason Turner

Electronic Theses and Dissertations

As regulations surrounding cannabis continue to develop, the demand for cannabis-based products is on the rise. Despite not producing the psychoactive effects commonly associated with THC, products containing cannabidiol (CBD) have gained immense popularity in recent years as a potential treatment option for a range of conditions, particularly those associated with pain or sleep disorders. However, due to current federal policies, these products have yet to undergo comprehensive safety and efficacy testing. Fortunately, utilizing advanced natural language processing (NLP) techniques, data harvested from social networks have been employed to investigate various social trends within healthcare, such as disease tracking and …

Characterization Of The Immunoglobulin Lambda Chain Across Diverse Human Populations., William Gibson

Electronic Theses and Dissertations

The adaptive immune system relies on a diverse set of over one hundred immunoglobulin (IG) genes across three genomic loci that are variably combined to form antibodies (Ab). The IG Lambda locus is one of two loci which encodes the IG light chain. The complexity of the IGL locus severely limits the effective use of standard short-read sequencing, limiting our knowledge of population diversity in these loci. We leveraged single molecule real-time (SMRT) long-read sequencing in conjunction with IGL-targeted DNA capture to develop the method IG-Cap for accurate and high-throughput sequencing of the IGL locus. We benchmarked this method using …

Inhibition Of Ras As A Novel Therapeutic Approach In Luminal B Breast Cancer., Raphael Ngozichi Jigo

Electronic Theses and Dissertations

Historically, the RAS oncoprotein has not been implicated in breast cancer due to less than 1% of breast cancer cases bearing oncogenic RAS mutations. Recently, however, it has been reported that greater than 60% of Luminal B breast cancer cases have a decreased expression of negative RAS regulators RASAL2 and DAB2IP. Thus, in many Luminal B breast cancers, RAS remains in a constitutively active state without mutation, in turn driving oncogenesis. To date, there are no FDA-approved direct inhibitors of wild type RAS. We have developed a direct RAS inhibitor that acts on wild type RAS using in silico drug …

A Practice-Based Inquiry Into The Correlation Between Nursing Retention Rates And Resiliency, Kelly J. Watson

Electronic Theses and Dissertations

Nurses are the frontline in the security of the United States. Their wellbeing and retention in the workforce is of the utmost of importance. Nurses are leaving at increasing levels with just over 27% turnover rates across the nation in 2021. Organizations are experiencing increasing fiscal losses and the average loss for a nurse leaving is just over $46,000. The prioritization of nurses’ wellbeing and taking steps to address policy that promotes the sustainability of this very valuable workforce has the potential to pay high dividends for nurses individually, the security of the nation, and the good of the organization. …

A Qualitative Content Analysis Of Nigerian Popular Music Genres: A Culture And Heritage Approach To Nation Branding, Cecilia Ashibel

Electronic Theses and Dissertations

This thesis explores the potential of Nigerian popular music as an approach to nation branding. The study employs qualitative content analysis to analyze select Nigerian music genres to examine how Nigeria is portrayed to international audiences and the economic benefits that can be derived from this form of branding. The analysis focuses on narrative themes of “the value of hard work,” “ethnic pride,” “lavish lifestyle,” and the impact of differences which were derived from the data. Findings indicate that Nigeria is globally reckoned for its musical prowess and rich cultural heritage. In highlighting the role of music in Nigeria’s political …

Sexual Trauma, Health, And The Moderating Effect Of Psychological Flexibility And Inflexibility, Gabrielle A. Caselman

Electronic Theses and Dissertations

Sexual trauma is linked to adverse health outcomes (e.g., D’Andre et al., 2011). Given the negative sequelae of sexual trauma, exploration of factors that influence the relation between sexual trauma and health outcomes is crucial. Current literature suggests that psychological flexibility and inflexibility may be factors in promotion of individuals’ health or pathology (e.g., Gloster et al., 2017). The current study sought to explore the variability in psychological flexibility and inflexibility among participants and the potential moderating effects of psychological flexibility and inflexibility on the relation between sexual trauma and both mental and physical health outcomes.

Moderation analyses failed to …

Characteristics Of Refractivity And Sea State In The Marine Atmospheric Surface Layer And Their Influence On X-Band Propagation, Douglas Matthew Pastore

Electronic Theses and Dissertations

Predictions of environmental conditions within the marine atmospheric surface layer (MASL) are important to X-band radar system performance. Anomalous propagation occurs in conditions of non-standard atmospheric refractivity, driven by the virtually permanent presence of evaporation ducts (ED) in marine environments. Evaporation ducts are commonly characterized by the evaporation duct height (EDH), evaporation duct strength, and the gradients below the EDH, known as the evaporation duct curvature. Refractivity, and subsequent features, are estimated in the MASL primarily using four methods: in-situ measurements, numerical weather and surface layer modeling, boundary layer theory, and inversion methods.

The existing refractivity estimation techniques often assume …

Applications Of Artificial Intelligence To Improve Coastal Ocean Modeling, Dongliang Shen

Electronic Theses and Dissertations

Numerical Modeling (NM) is widely used to simulate and predict hydrodynamic processes and marine particle movements in coastal oceans, particularly during extreme weather events and emergencies. NM offers the capability to realistically simulate multiple state variables and fill gaps caused by scarce observations. However, inherent uncertainties exist in all NMs, primarily arising from the following three factors: 1) insufficient observations leading to uncertain model initial and boundary conditions, 2) inevitable truncation errors due to coarse model resolution, and 3) imperfect physics parameterization schemes for sub-grid processes, especially those related to waves. The consequences of these uncertainties are that 1) even …

Learning Mindset Dimensions And Completion Status Of Tennessee Community College Students, Donna Sue M. Shellman

Electronic Theses and Dissertations

The purpose of this nonexperimental, quantitative study was to analyze relationships between three learning mindset dimensions (growth mindset; purpose and value; and sense of belonging) to retention and persistence to graduation among first-time, full-time Tennessee community college student graduates and nongraduates who attended one of 13 institutions in Fall 2019. In addition to comparing Tennessee community college graduates and nongraduates’ learning mindset dimensions, I analyzed student subgroups to explore those dimensions with regard to gender and race. Additional analyses included correlations between students’ growth mindset scores; purpose and value scores; and social belonging scores.

Analyses included Tennessee Board of Regents’ …

Investigation Of Possible Inflammatory Response After Ultrasound And Microbubble Procedure In The Spinal Cord., Jenna Wilkerson

Electronic Theses and Dissertations

The purpose of this experiment is to explore the inflammatory effects of focused ultrasound paired with intravenously delivered microbubbles when used in the lumbar spinal cord. There are currently very few pharmaceuticals that can successfully enter the blood spinal cord barrier (BSCB). This technique used at the lumbar enlargement might allow targeted treatment of pathologies involving the spinal cord.

To test the possible inflammatory response of this technique, an animal experiment was performed. 15 animals were given a T12 laminectomy and allowed to fully recover. Once recovered, all animals received FUS+MB at L2 and were euthanized in groups of five …

Development And Application Of A Microfluidic Platform For Quantifying Intra-Tumoral Compressive Stress., Zachary P. Fowler

Electronic Theses and Dissertations

Cancer progression is linked to the emergence of aberrant mechanical signaling in the tumor microenvironment. Modulation of extrinsic signals, such as ECM stiffness and composition, have been thoroughly explored. However, the development of solid stresses within the tumor remains poorly understood. To address this, we have developed a microfluidic platform that generates deformable alginate microbeads that allow for the quantification of compressive stresses generated within a growing glioblastoma (GBM) tumorsphere. PDMS microfluidic devices were fabricated via SU-8 mold with channels ranging from 10µm-40µm in diameter. Fluorescently labeled sodium alginate underwent a cross-linking reaction within the device to generate monodisperse beads …

Addition Of Process Control Experiment To Unit Operations Ii Laboratory., Bradley Esselman

Electronic Theses and Dissertations

Process control is an essential aspect of manufacturing, contributing to improved process safety, efficiency, product consistency, and energy optimization. Chemical engineers are often responsible for ensuring the safe, efficient, and cost-effective operation of industrial processes, and process control plays a pivotal role in accomplishing this.

Chemical engineering students at the University of Louisville complete the course, Elements of Process Control, during the second semester of their fourth year. This lecture-based course offers limited hands-on, practical experience. To supplement the lack of hands-on experience in the classroom, a new process control experiment was designed and implemented into the Unit Operations …

Design And Evaluation Of A Multi-Functional Surgical Device For Microgravity Surgeries., Sienna Shacklette

Electronic Theses and Dissertations

No abstract provided.

Linguistic Features Of Metaphor, Metonymy And Narrative Gap In “The Yellow Wallpaper:” A Literary Analysis, Sherry Kaye Ms.

Electronic Theses and Dissertations

In 1890, Charlotte Perkins Gilman wrote a piece of fiction that reflected her personal experience for treatment of nervous exhaustion. The story she developed created controversy and comment after it was published and, years later, agitation among feminists who found allegories of truth in its narrative. This thesis explores the use of linguistic features employed by Gilman to establish cognitive connections between physical structures and social institutions, such as marriage and domesticity, that confine women within contractual obligations. Gilman’s use of extended metaphor challenges conventional conceptions of the home, inanimate objects, and institutional authority and her use of metonymy extrapolates …

Co-Flowering Community Effects On The Relative Contribution Of Pollen Quantity And Quality Limitation To The Reproductive Success Of Four Clarkia Species, Emma Moore

Electronic Theses and Dissertations

More than 60% of plant populations experience low pollen availability which limits seed production (pollen limitation). Pollen limitation occurs due to low quantity or quality of pollen delivered to stigmas. Despite its ubiquity in nature, to date we still have limited understanding of the drivers of pollen limitation in plant communities. Plants typically occur in diverse communities where pollinator sharing is common and can influence quality and quantity aspects of pollen limitation. Co-flowering species can attract larger numbers of pollinators or they can compete for pollinators affecting pollen loads on stigmas. Pollinator competition may also lead to higher rates of …

Understanding The Role Of Sabp2-Interacting Protein (Sip) 428: An Nad+-Dependent Deacetylase Enzyme In Abiotic Stress Signaling Of Nicotiana Tabacum, Mariam Onabanjo

Electronic Theses and Dissertations

Abiotic stresses are constantly rising and pose a very high risk to global agricultural productivity and food security. Some plants have evolved several innate pathways for defense against these stresses. Hence, understanding stress signaling pathways can help develop crop plants with higher stress tolerance. The salicylic acid-mediated signaling pathway is important in plants experiencing biotic and abiotic stresses. In previous studies, SABP2-Interacting Protein (SIP-428) has been shown to be a negative regular of plant growth under abiotic stress. This study aimed to investigate the roles of SIP-428 in the ROS signaling of tobacco plants. We investigated transgenic RNAi-silenced lines of …

The Initial Validation Of A Self-Care Belief And Behavior Questionnaire In The Iecmh Workforce, Julia Najm

Electronic Theses and Dissertations

The Infant and Early Child Mental Health (IECMH) workforce is essential in improving the lives of vulnerable children and families. IECMH practitioners are exposed to challenging emotional experiences which increases their risk of internalizing disorders, burnout, and emotion regulation difficulties, especially in the time of COVID-19. Thus, it is important to identify possible interventions to increase provider wellness in the face of taxing work. The construct of self-care offers a promising area of study as a possible intervention point. However, current operationalizations of self-care have been limited and have emphasized behavioral components rather than cognitive components (e.g., beliefs) pertinent to …

Secondary Educator And Administrator Perceptions Of Positive Behavior Interventions And Supports And Student Academic Achievement, Cynthia Everitt

Electronic Theses and Dissertations

This qualitative study addresses secondary educator perceptions of Positive Behavioral Interventions and Supports (PBIS) and student academic achievement. PBIS is a proactive approach with a multitiered framework. When used properly, PBIS can be a tool for school faculty to establish behavioral expectations and procedures, prevent disruptive behavior, and improve the school climate and culture. This phenomenological study was conducted using two secondary schools in West Virginia. Participants were identified and chosen through purposive sampling techniques according to their years of experience teaching and utilizing PBIS interventions.

The data for this study included unstructured, open-ended interviews based on three research questions. …

“Just As Scared As I Am”: Daughters’ Perspectives Of The Impact Of The Overturning Of Roe V. Wade On Mother-Daughter Reproductive Conversations, Casadie Smith

Electronic Theses and Dissertations

Existing literature has identified mothers as the primary reproductive educators of their daughters and has determined mother-daughter conversations about reproduction to be an indicator of daughters’ sexual and reproductive behaviors. The overturning of Roe v. Wade on June 24, 2022, had an immediate impact on the reproductive lives of many people, including daughters. Through one-on-one interviews with 10 daughters, this qualitative study identifies three changes in mother-daughter reproductive conversations that were influenced by the overturning of Roe v. Wade: (a) The initiation of conversations, (b) the topics of conversations, and (c) the tone of these conversations. The results of this …

Gratitude And Sleep Quality In Primary Care: Mediating Effects Of Health Self-Efficacy, Health Behaviors, And Psychopathology, Heather R. Altier

Electronic Theses and Dissertations

Sleep disturbances are prevalent among primary care patients, and psychological dysfunction, including stress, anxiety, and depression, are robust contributors to poor sleep health. Yet, the presence of potential protective characteristics, such as health self-efficacy and engaging in adaptive health behaviors, may mitigate such outcomes. Gratitude (i.e., recognition and appreciation of experiences, relationships, and surroundings), a positive psychological cognitive-emotional characteristic, may serve as a catalyst of these beneficial downstream effects, given its association with improved health functioning and sleep. In a sample of primary care patients (N = 869) from 50 urban and 30 rural practices in Germany, health self-efficacy …

Use Of Transposon Screening For Salicylic Acid-Assisted Desiccation Killing In Salmonella, Shannon D. Elliott

Electronic Theses and Dissertations

Salmonella enterica serovar Typhimurium is one of the most prevalent food-borne pathogens, affecting millions around the world every year, making it a threat to global health. Salmonella possesses the ability to survive the normally lethal condition of desiccation, however, discovery of the genes and mechanisms behind this phenomenon are still ongoing. Using a transposon mutagenesis approach to construct a broad transposon library, this study aimed to uncover genes that may be contributing to changes in Salmonella’s survivability under desiccation, particularly when exposed to the antimicrobial molecule salicylic acid. Building on previous findings showing salicylic acid can alter cell viability …

The Old Family Clock: Exploring High Variation Of Chronotype In The Common House Spider, Parasteatoda Tepidariorum, Caitlin Jones

Electronic Theses and Dissertations

Circadian rhythms are often tightly confined around a mean of 24 hours with little variation in traditional model organisms in the absence of environmental time cues. Some spider species fall well outside this normal range with mean periods of 18 hours and variation around these means of 6 hours or more. This extreme variation in circadian rhythm is not well-understood and is the focus of the current study. Using Parasteatoda tepidariorum as a model organism, we investigated whether variation in eight circadian parameters could be explained by genetic variability, environmental conditions, or an endogenous feature of the circadian system of …

Analyzing The Influence Of Mathematics Intervention Teacher Actions On Students' Mathematics Identities: An Examination Of Bipoc Student Perceptions And Past Learning Experiences., Sydni P. Morris

Electronic Theses and Dissertations

This dissertation examines mathematics education's past and present state in the United States, emphasizing mathematics intervention instruction. This dissertation includes a complex and critical analysis of intervention practices and historical and structural inequities based on race present in these interventions and mathematics education. In combination, it examines the construct of mathematics identities, their role in student success with mathematics, and trends surrounding mathematics education and its impact on populations of students of color. Using Critical Race Theory as an underlying framework and Critical Counter-Narrative as a methodology, it argues a need for marginalized student voices to be present in the …