Digital Commons Network^™

Exploring The Impact Of Ionizing Radiation On Security And Reliability In Modern Semiconductor Memories, Umeshwarnath Surendranathan

Dissertations

Radiation effects in semiconductor devices have gained great traction in recent years due to an exponential growth in space exploration. The harsh conditions of space, devoid of the atmosphere and Earth's magnetic field, pose considerable challenges to electronic systems due to ionizing radiation exposure. While radiation-hardened (rad-hard) components are continually under development, they often lag several technology generations compared to commercial off-the-shelf (COTS) parts. Notably, rad-hard memories, particularly in terms of capacity (megabytes vs. terabytes) and cost, fall short compared to regular COTS memories. This underscores the compelling need to evaluate the radiation tolerance of COTS memories. This dissertation focuses …

A Large-Sample X-Ray Absorption Line Analysis In Search Of The Missing Baryons In The Hot Whim, David Spence

Dissertations

A well known problem in astrophysics that has seen a significant amount of investigation in recent years is the ”missing baryons problem”, in which up to 40% of baryons have been reported missing at low redshifts [62]. Predictions show that these remaining baryons are likely residing within the Warm-Hot Intergalactic Medium (WHIM). The process of finding these baryons involves searching for absorption line systems in the WHIM, and using column densities of those absorbing ions to calculate the cosmological density of the medium. Several wide scale FUV studies (e.g. [21]) have been completed to work towards solving this problem, but …

Adaptive Discrete Time Sliding Mode Control For N-Th Order Flapping-Wing Micro Air Vehicles With Unknown Parameters, Joshua Hill

Dissertations

Small aerial systems, such as nature-inspired flapping-wing micro aerial vehicles (FWMAV), operate in uncertain and dynamic environments that are subject to unknown disturbances, e.g., wind gusts. With the proliferation of inexpensive system components, extensive research has been dedicated to improving the operation of these FWMAVS, both in civilian and military applications. Given dynamic environments and variations in individual components, sliding mode control has become an increasingly applied control method for FWMAV. Its robustness proves invaluable to ensure stability in the presence of uncertain system parameters and environmental disturbances. This dissertation presents three discrete-time sliding mode control (DSMC) methods and applies …

Development Of A Continuum Damage Constitutive Model And Simulation For Brittle Materials In Space Infrastructure Application, Luis Eduardo Deganis

Dissertations

The purpose of this work is to develop a continuum damage constitutive material model and apply it to structural response characterization of brittle materials for in-situ construction of space infrastructure. This research improves and expands the utility of the physics-based dominant crack algorithm (DCA) model in order to account for very low-strain rate phenomena in plain concrete structures. The DCA model is strain-rate dependent and has been effectively utilized for highly dynamic phenomena. The model has a strong basis in micromechanics and is able to capture the strain-softening response of brittle materials. The newly developed constitutive model can be easily …

A New, Intuitive Method For The Design And Analysis Of Multi-Pass Cavities, Adam S. Mansor

Dissertations

This dissertation develops a new analytical approach for designing and analyzing multi-pass cavities like the Herriott cell employing the graphical yӯ diagram approach. The new technique can be deployed in spectroscopy absorption detection, femtoseconds laser cavities, or any off -axis spherical mirror interferometers applications. Such a system can be uniquely designed and evaluated by entering a few parameters that define the required physics for the cell, the packaging size limits for the system and the probe beam size, plus two user selected parameters. The existing design method, developed by Herriott, is discussed and then the yӯ diagram method is presented …

Application Of A New Scale-Resolving Turbulence Model To Supersonic Retropropulsion Flows With Chemistry, Gabriel C. Nastac

Dissertations

Turbulent compressible flows are ubiquitous in many engineering applications of flight and propulsion. Computational fluid dynamics simulations are commonly performed to analyze these flows. Scale-resolving turbulence models inherently better capture various flow phenomena, including separation and mixing, as well as enable predictions of fluctuations, which can be critical for design compared to traditional steady-state turbulence models. In this work, new scale-resolving blended Partially-Averaged Navier-Stokes (BPANS) turbulence models are developed to account for compressibility effects and are employed to efficiently simulate turbulent compressible flows. Specifically, supersonic retropropulsion flows are investigated. Supersonic retropropulsion is a key technology for next-generation rockets. The new …

"Who The Hell Am I? What Am I Bringing In Here?": A Phenomenographic Exploration Of Antiracist Mentor Development, Kelly Lynn Mack

Dissertations

Teacher attitudes toward racial diversity profoundly impact students, especially when compounded by teacher and student demographic disparities. Despite the purported goal of addressing biases and deficit thinking that limit teachers' ability to support all learners, antiracist pedagogy in teacher credentialing is poorly understood. Also included in the credentialing process, newly qualified teachers (NQTs) in California engage in a two-year induction program, collaborating closely with an induction mentor to attain their clear credential. Employing a qualitative, phenomenographic approach, this study explored how mentors within a longstanding induction program understood and implemented antiracist pedagogy. The research uncovered significant insights into (a) dimensions …

Spiritual Experiences Of Young People With Cognitive Impairments Within Christian Communities Of Faith, Lea Danihelova

Dissertations

This study was initiated with the primary objective of delving deep into the spiritual experiences of individuals living with cognitive impairments. The research was centered on seven young adults with cognitive impairment who were members of the Christian communities of faith and resided in Bratislava, the capital of Slovakia. The study focused on giving voice to these young people since there were no studies about the spirituality of people with cognitive impairment done in central Europe. The hermeneutic phenomenological approach was chosen as the research method due to its capacity for facilitating personal interactions, thus enabling a comprehensive understanding of …

Cbct Perceptions Of Radiology Leaders In The Midwest Dental Schools: A Qualitative Study, Tenzin Dadul

Dissertations

Problem

The integration of Cone Beam Computed Tomography (CBCT) in dental education is hindered by a lack of formal training among radiology leaders, insufficient institutional support, and financial constraints. Despite the proven efficacy of CBCT in enhancing diagnostic accuracy and treatment planning, its adoption in pre-doctoral curricula remains limited. This gap in education poses significant challenges for dental graduates, who are increasingly expected to utilize advanced imaging technologies in clinical practice.

Purpose of Study

This qualitative study aimed to explore the perceptions of radiology leaders in Midwest dental schools regarding the integration of CBCT education into pre-doctoral curricula. The objectives …

Odd Fellows: The Intersection Of Arminianism And Calvinism In The Writings Of Desmond Ford And F.F. Bruce, Samuel Pagán De Jesus

Dissertations

The Topic

In the 1970s, the Seventh-day Adventist church’s theological struggles over righteousness by faith and perfectionism revealed that Adventists were confused about their Protestant identity and what it meant to have the assurance of salvation. That struggle is exemplified in Desmond Ford’s writings. His doctoral studies under evangelical scholar F. F. Bruce prompted the Historic Adventists to wonder whether Ford had abandoned the Arminian synergistic soteriology for Calvinism’s monergism.

The Purpose

The purpose of this study was to explore to what extent Frederick F. Bruce’s Reformed views, theological assumptions, and commitments were shared by and reflected in Desmond Ford’s …

Reporting And Addressing Sexual Harassment At Four Institutions Of Higher Learning In Zambia: A Quantitative Study Of Related Attitudes And Perceptions, Earlymay Chibende

Dissertations

Problem

Sexual harassment is a social ill that exists across nations, socio-economic backgrounds, races, nationality, ethnicity, age groups, and sex. Although both male and female members of society experience sexual harassment, research shows that a greater percentage of sexual harassment victims are women (Whitley & Page, 2015; CharterJee, 2018). A comparison of the prevalence of sexual harassment at workplaces and educational institutions shows that sexual harassment is more widespread at institutions of learning than at workplaces. Research on the prevalence of attitudes and or perceptions toward sexual harassment in institutions of higher learning shows that between 10%- 68% of female …

Enhancing Organisational Performance Through Patient-Focused Learning Excellence In The Biopharmaceutical Industry, Lori Richter

Dissertations

Drug shortages, quality defects and challenges regarding innovation within the biopharmaceutical industry pose significant risks to patient safety and organisational performance. These problems persist despite the many scientific, technological and economic advances over the past several years in a well-funded, high-revenue industry operated by highly qualified personnel. Evidence suggests that the industry has yet to fully realise the potential for building organisational capabilities to enable learning from mistakes to enhance performance outcomes. This research study explored how biopharmaceutical companies can learn from their mistakes and embrace a culture of learning in order to reduce quality defects and drug shortages by …

A Fully Automated Global Post-Hoc Method Based On Abstract Argumentation For Explainable Artificial Intelligence And Its Application On Fully Connected Dense Deep Neural Networks, Giulia Vilone

Dissertations

Explainable Artificial Intelligence (XAI) has rapidly grown in the past decade due to the prevalence of machine learning, especially deep learning, in fields like healthcare and finance. While these models excel in accuracy, their complexity hampers transparency and interpretability. Ensuring understandable explanations for AI predictions fosters trust, prevents errors, complies with regulations, and enhances model refinement. The research project outlined in this thesis unfolds in phases. It commences with a comprehensive review of existing XAI studies, contributing to the field’s knowledge by proposing a taxonomy that organises theories and notions related to explainability, the evaluation approaches for XAI methods, and …

Variability In Semidiurnal Surface And Internal Tides In Global Ocean Model Simulations, Harpreet Kaur

Dissertations

This dissertation focuses on semidiurnal (D2) surface and internal tides. Chapter 2 investigates the transition of M₂ barotropic Kelvin waves into Hybrid Kelvin-Edge (HKE) waves and the associated generation of internal tides at widening shelves using theory and a realistic global baroclinic Hybrid Coordinate Ocean Model (HYCOM) simulation. To understand the effect of complex, realistic bathymetry on the HKE wave transition, we perform quasi-realistic barotropic HYCOM simulations of the Celtic Sea/Bay of Biscay shelf areas. We conclude that the HKE wave transition is most likely masked by the effects of complex bathymetry and offshelf baroclinic fluxes cannot be exclusively …

Depressurization Characteristics Of Steam-Based Reciprocating Vacuum Pump, Hongling Deng

Dissertations

This dissertation introduces a novel vacuum technology that leverages low-pressure saturated steam and cooling-controlled condensation, offering an efficient way to utilize low-grade thermal energy sources like waste heat, steam, or solar energy. At the heart of this technology is a unique duo-chamber vacuum pump system, featuring a reciprocating piston and a heat-conductive wall, designed to generate a vacuum through steam-condensation and cooling processes.

The core of this research lies in developing and validating mechanistic models for the steam-condensation depressurization process, a complex phenomenon involving phase change and transport mechanisms. Prior to this work, these mechanisms were not sufficiently modeled or …

The Role Of Semaphorins In Response To Injury In C. Elegans Neurons, Maria Belen Harreguy Alfonso

Dissertations

When neural tissue is injured by trauma, delicate neuronal processes such as axons and dendrites are prone to lesion damage and often disconnect. The molecular, cellular, and circuit mechanisms that underlie the regrowth and reconnection of these processes and the recovery of behavior are major challenges in the fields of neuroscience, regeneration, and resilience. At the molecular and cellular levels, signaling pathways that mediate neuronal growth cone guidance during development can play a role in neuronal regeneration and recovery from injury. One family of signaling proteins involved in this process comprises the highly conserved semaphorins and their receptors, the plexins. …

Model-Based Deep Autoencoders For Clustering Single-Cell Rna Sequencing Data With Side Information, Xiang Lin

Dissertations

Clustering analysis has been conducted extensively in single-cell RNA sequencing (scRNA-seq) studies. scRNA-seq can profile tens of thousands of genes' activities within a single cell. Thousands or tens of thousands of cells can be captured simultaneously in a typical scRNA-seq experiment. Biologists would like to cluster these cells for exploring and elucidating cell types or subtypes. Numerous methods have been designed for clustering scRNA-seq data. Yet, single-cell technologies develop so fast in the past few years that those existing methods do not catch up with these rapid changes and fail to fully fulfil their potential. For instance, besides profiling transcription …

Development Of Novel Protein Digestion And Quantitation Methods For Mass Spectrometic Analysis, Yongling Ai

Dissertations

Proteins are the workhorses of biology, playing multifaceted roles in maintaining cellular function, signaling, and response to environmental cues. Understanding their abundance and dynamics is pivotal for unraveling the complexities of biological processes, which underpins the foundations of molecular and cellular biology. Accurate measurement of protein quantities provides insights into cellular homeostasis, facilitates the discovery of biomarkers, and sheds light on the molecular mechanisms of diseases, bridging the gap between the molecular intricacies of proteins and their functional consequences in health and disease. The evolution of protein quantitation methodologies, from classical colorimetric assays to sophisticated mass spectrometry-based approaches, has expanded …

Homeless Barriers: A Phenomenological Study Of Service Providers In Thurston County, Washington State, Michael Meredith

Dissertations

Purpose: This qualitative phenomenological study aims to describe the perceptions of homeless service providers in Thurston County, Washington State, and describe barriers to the homeless seeking assistance. This study interviewed ten Thurston County service providers about their perception of the barriers preventing the unsheltered homeless from using available services. Identifying barriers and developing strategies to reduce or remove them is expected to reduce or eliminate homelessness.

Methodology: This qualitative phenomenological study describes the homeless service providers' perceptions of the homeless and the barriers to the homeless seeking assistance. The researcher conducted interviews with a sample of ten service providers to …

Establishing A Novel Lipid-Polyamine Metabolic Connection To Virus Replication, Yazmin Edith Cruz Pulido

Dissertations

Polyamines are small positively charged alkylamines found in all living cells. These ubiquitous molecules have been found to play a variety of roles ranging from stabilizing nucleic acids (DNA and RNA) to cellular proliferation. Studies have also identified roles for polyamines in viral packaging and viral enzyme function. However, the role of polyamines on cellular components and their effect on viral replication is less known. In our efforts to identify the lipid-polyamine metabolic connection to virus replication we utilized a human hepatocyte cell line in which polyamines were depleted via pharmacological or genetic approaches and studied the effects on lipid …

Coworkers And Leaders: The Relationship Between Trustworthiness, Trust, And Employee Engagement, Lianne Young

Dissertations

A highly engaged workforce provides numerous organizational and individual benefits (Shuck et al., 2016), the culmination of which leads to a competitive advantage difficult to emulate (Burke et al., 2013). It remains challenging to understand how engagement develops, with little research available explaining the process (Shuck, 2020). High employee engagement levels provide a competitive advantage, but stagnant engagement levels remain a significant obstacle (Shuck, 2020).

Shuck (2020) recommends further research focusing on methods to increase engagement. Trustworthiness and trust are antecedents and drivers of engagement (Chughtai & Buckley, 2008; Federman, 2010; SHRM, 2017). A lack of trust has negative impacts …

Relationship Between School-Wide Positive Behavior Interventions And Supports, Student Achievement, And Teacher Efficacy In High Poverty Rural Alabama Elementary Schools, William Combs

Dissertations

The purpose of this research study is to determine if relationships exist between the level of School-wide Positive Behavior Interventions and Supports implementation, student academic achievement, and teacher self-efficacy in high-poverty rural Alabama elementary schools. The research encompassed a comprehensive analysis of existing literature, incorporating historical and policy-related context, theoretical underpinnings, relevant studies, and expert viewpoints. Additionally, the research involved the gathering and examination of data, presentation of findings, establishment of conclusions, and suggestions for prospective research directions. The primary objective of this study is to investigate potential correlations between the extent of SWPBIS (School-Wide Positive Behavior Interventions and Supports) …

Thermally Rearranging Polyimide Networks For High-Temperature Applications, William Guzman

Dissertations

High-performance polymers can retain functional properties when exposed to long-term or short-term durations of harsh conditions, such as mechanical action, at elevated temperatures (>177 °C). A mixture of intramolecular and intermolecular forces of and between polymer chains provide excellent property retention at elevated temperatures. Specifically, the highly aromatic nature of high-performance polymer backbones provides outstanding thermal stability, which is typically attributed to π-π stacking. However, the interrelationship between thermal stability and high aromaticity creates a challenging structure-processing relationship paradigm, which causes poor polymer processability in most high-performance polymers. Herein, it was demonstrated that rationally designing a crosslinking phenylethynyl imide …

Timeseries Forecasting Of U.S. Housing Price Index Using Machine Learning And Deep Learning Models, Krishna Chaitanya Nunna

Dissertations

Time series forecasting is a promising technique for various applications which predicts future values or patterns by taking historical data as base. Forecasting future trends is very beneficial for different industries to make valuable decisions and strategies. One such industry is housing market; it has biggest influence on U.S. economy. Housing price index (HPI) is a one of the crucial economic indices published by various government funded and private agency to benefit several industries and individuals for better analysis of future trends of housing market.

Several factors influence the HPI, economical, geographical, and demographic features. Development of traditional time series …

Heterotypic Interaction Of Α-Synuclein And Tdp-43 In Neurodegenerative Diseases, Shailendra Dhakal

Dissertations

Amyloid aggregates of specific proteins form important pathological hallmarks in many neurodegenerative diseases, defining neuronal degeneration and disease onset. Recently, increasing numbers of patients show co-morbidities and exhibit clinical and pathological overlaps between multiple neurodegenerative diseases including α-synucleinopathies and TDP-43 proteinopathies. These overlaps are often accompanied by co-localization of α-synuclein (αS) and TDP-43 enhancing the possibility of direct interactions to generate heterotypic amyloids with distinct cellular consequences. To understand this, we investigate the interaction of α-synuclein (αS) and prion-like domain of TDP-43 (TDP-43 PrLD) in both homogenous and inhomogeneous phases. Firstly, we show that monomeric TDP-43 PrLD and αS interact …

Intelpvt And Opt-Stvit: Advances In Vision Transformers For Object Detection, Classification And Video Recognition, Divya Nimma

Dissertations

Since the advent of Transformers, followed by Vision Transformers (ViTs), great success has been achieved by researchers in the field of computer vision and object detection. The difficult mechanism of splitting images into fixed patches posed a serious challenge in this arena and resulted in the loss of useful information at the time of object detection and classification. We propose an innovative Intelligent-based patching mechanism to overcome the challenges and integrate it seamlessly into the conventional Patch-based ViT framework. The proposed method enables the utilization of patches with flexible sizes to capture and retain essential semantic content from input images, …

An Analysis Of The Effects Of Visual Art And Gender On Secondary Students’ Achievement In Geometry, Johnny Gary Iii

Dissertations

Students’ understanding of geometry can be hampered in part because of their inability to visualize, describe, draw, and recognize images and shapes. What if art and making could support students’ mathematics learning and interest and help them over the geometry hurdle? This work investigated visual-arts integrated geometry lessons to explore its impact on high school students’ understanding and attitudes. This study used a quasi-experimental mixed methods design, with a pre- and post- survey and interview data collected from geometry students at Mississippi high school. The control group was taught the same geometry content using a traditional curriculum, and the treatment …

Structural Features Of Hiv-1 Integrase In The Late Stage Of Viral Replication, Tolga Catmakas

Dissertations

HIV-1 integrase (IN) is an essential enzyme for the viral life cycle as it integrates viral genomic material into the host cell genome. In addition to its’ essential catalytic function, IN has another important non-catalytic role where it binds the viral RNA to facilitate successful particle maturation during the viral life cycle. A significant number of IN mutants, addressed as class II IN mutants, show various defects, affecting different steps of the viral life cycle. Class II IN mutants exhibit aberrant morphology where viral ribonucleoprotein particles are mislocalized outside of the capsid core. This phenomenon can be observed in the …

Engagement In Mental Health Research: The Role Of Mental Health Awareness And Perceived Intervention Stigma In Clinical Research Engagement Among African American Faith Communities, Camelia Harb

Dissertations

The dearth of participation in clinical research by marginalized racial and ethnic groups is a commonly cited limitation of research studies. To better understand research engagement among marginalized groups, this study proposed a mixed methods design examining the roles of mental health awareness and perceived intervention stigma on the capacity to engage in clinical research among a sample of African American faith community members. The primary aims were to: 1) examine the associations between and predictive roles of mental health awareness and perceived intervention stigma on clinical research engagement; 2) evaluate the moderating role of perceived intervention stigma; and 3) …

Power-Up With Emotional Intelligence: Exploring Flight Attendant Leadership And Crew Resource Management In A Dynamic Post-Pandemic Travel Environment, Carlin Laviolet Clarke

Dissertations

In the post-pandemic travel environment, disruptive passengers fail to accept flight attendants’ leadership and cause unruly incidents that compromise flight safety, damage airlines, and present behavioral challenges that can lead to physical harm (Al-Arshani, 2021; Albert, 2016; Araiza, 2022; Albert, 2016; FAA, 2021; Inspire Academy, n.d.-a.; International Air Transport Association [IATA], n.d.-b; James, 2022; Pederson et al., 2021; Ramona & Anbro, 2017; Timmis et al., 2018; TSA, 2021; Wong & Neustaedter, 2017). Flight attendants rely on Crew Resource Management (CRM) skills to manage inflight incidents; however, CRM promotes team effectiveness and flight attendants are often dispersed throughout the cabin and …