Digital Commons Network^™

Effect Of Pressure On Viscoplasticity And Its Usefulness In Designing Impact Devices, Marouane Jarachi

Theses and Dissertations

This work investigates the interactions between impact devices and material response in the realm of solid mechanics, utilizing explicit finite element analysis and experimental methods based on the split-hopkinson pressure bar. It focuses on understanding how tools like jackhammers use hammer strikes to generate pressure waves, then the wave is transferred through a chisel to materials such as rocks to cause fracture. The interaction between the wave and the rock is complex. Under dynamic loading the mechanical response of materials changes and significant losses occur due to reflections and inefficient pressure states. This research explores how chisel geometry can be …

Uncertainty Analysis For Runoff, Crop Yield, Sediment, And Nutrient Loads In The Mississippi Delta Region Using Apex, Javier Fernando Méndez Monroy

Theses and Dissertations

Understanding the dynamics of agricultural basins has been difficult for decision-makers when developing cost-effective plans. An uncertainty analysis evaluates the impact of information gaps on hydrologic model’s output and performance. The Agricultural Policy/Environmental Extender (APEX v1501) was used to predict runoff, crop yield, sediment load, total phosphorus, and total nitrogen from agricultural fields in the Mississippi Delta to investigate the impact of using different input variables (climate, soils, and management practices) on mechanistic models. Results indicated that the use of surrogate information such as weather data from close weather stations, a predominant soil series, and simulated irrigation schedules, could be …

The Role Of Subsurface Dynamics In Cometary Outbursts, Ahmad Sohani

Theses and Dissertations

Comets, often referred to as cosmic time capsules, serve as invaluable repositories of information from the nascent phases of our solar system. Varying significantly in size, with nuclei ranging from a few kilometers to tens of kilometers in diameter, these celestial bodies are complex, porous aggregates of organic molecules, silicate particles, and entrapped volatile gases. Their orbits, which can be categorized into the Main Belt, the Kuiper Belt, and the Oort Cloud, offer distinct insights into their origins and the early conditions of the solar system. Understanding the physical processes occurring within these nuclei is critical, particularly in the context …

Spatial And Temporal Vulnerability Analysis Of Natural Disasters Due To Climate Change, Weiwei Xie

Theses and Dissertations

Natural disasters have become more severe and frequent than previous assessments with global warming. The increasing risk of natural disasters presents different groups of populations with diverse vulnerabilities, particularly those underrepresented social groups which need specific support before, during, and after extreme disasters. Hence, it is highly desired to examine vulnerability quantitatively and qualitatively across different social groups in risk to natural disasters. This dissertation study aims to investigate the measure of social vulnerability to two types of climate change-related natural disasters: sea-level-rise floodings and wildfires. In the study of sea-level-rise floodings, high-risk flooding areas are first identified for a …

Theory, School Policy, And Practices In Education And Culture In A Classroom Setting For Minority Students, Philip Turner

Theses and Dissertations

This qualitative case study investigates the discrepancies between theory, school policy, and practices within educational settings, particularly concerning minority students. Grounded in the persistent racial achievement gaps documented in educational literature, the study aims to understand the challenges and successful strategies for bridging these gaps. Drawing upon Critical Race Theory (CRT), Intergroup Contact Theory, and Stereotype Threat as conceptual frameworks, the research explores the experiences of eight participants through thematic analysis. Three overarching themes emerged: challenges aligning theories, policies, and practices; successful strategies for alignment; and unsuccessful strategies. Findings underscore the importance of culturally responsive curriculum, teacher professional development, student- …

Performance Evaluation Of Low-Cost Gps Machine Guidance Systems For Livestock Production Forage And Pasture Management Applications, Conner Childress Wright

Theses and Dissertations

Global Positioning System (GPS) machine guidance aids in the precise navigation and piloting of farm machinery and serves to boost productivity and optimize farm operations. Characterization of low-cost GPS guidance systems for livestock production operations is necessary for return on investment (ROI) decision making. The objective of this research is to characterize the accuracy of four commercially available low-cost ($985 - $4,200) wide area augmentation system (WAAS) corrected GPS guidance systems. Testing procedures were designed in accordance with the ASABE/ISO standard 12188-2 for testing of satellite-based guidance systems during straight line travel. The vehicles lateral deviation of a planned path, …

Enhancing Data-Driven Process Quality Control In Metal Additive Manufacturing: Sensor Fusion, Physical Knowledge Integration, And Anomaly Detection, Christian E. Zamiela

Theses and Dissertations

This dissertation aims to provide critical methodological advancements for sensor fusion and physics-informed machine learning in metal additive manufacturing (MAM) to assist practitioners in detecting quality control structural anomalies. In MAM, there is an urgent need to improve knowledge of the internal layer fusion process and geometric variation occurring during the directed energy deposition processes. A core challenge lies in the cyclic heating process, which results in various structural abnormalities and deficiencies, reducing the reproducibility of manufactured components. Structural abnormalities include microstructural heterogeneities, porosity, deformation and distortion, and residual stresses. Data-driven monitoring in MAM is needed to capture process variability, …

A Bilevel Approach To Resource Allocation For Utility-Based Request-Response Systems, Tanner Jack Sundwall

Theses and Dissertations

We present a novel bilevel programming formulation that aims to solve a resource allocation problem for request-response systems. Our formulation is motivated by potential inefficiencies in the allocation of computational resources to incoming user requests in such systems. In our experience, systems often operate with a surplus of resources despite potentially incurring unjustifiable cost. Our work attempts to optimize the tradeoff between the financial cost of resources and the opportunity cost of unfulfilled user demand. Our bilevel formulation consists of an \textit{upper} problem which has a constraint value appearing in the \textit{lower} problem. We derive efficient methods for finding global …

Synthesis Of High-Quality Cost Effective Zno Nanorods For Photovoltaic Applications, Ghusoon Jalil Ibrahim Al Bazzar

Theses and Dissertations

Due to its outstanding structural, optical, and electrical properties, zinc oxide (ZnO) has received considerable attention from researchers. Even though there is a high demand for functional devices involving ZnO films and nanostructures, synthesizing devices comprising ZnO nanostructures requires expensive and time-consuming techniques that have limited their viability for comprehensive applications. Thus, there is a high demand for high-quality, cost-effective ZnO nanostructures. We have optimized the simple, low-cost, and time-efficient electrochemical deposition (ECD) technique to successfully synthesize high-quality vertically aligned ZnO nanorods to bridge this gap between fundamental and applied research. Characterization of their structural properties through x-ray diffraction and …

Using Hybrid Machine Learning Models For Stock Price Forecasting And Trading., Ahmed Khalil

Theses and Dissertations

Trading stocks of publicly traded companies in stock markets is a challenging topic since investors are researching what tools can be used to maximize their profits while minimizing risks, which encouraged all researchers to research and test different methods to reach such a goal. As a result, the use of both fundamental analysis and technical analysis started to evolve to support traders in buying and selling stocks. Recently, the focus increased on using Machine learning models to predict stock prices and algorithmic trading as currently there is a huge amount of data that can be processed and used to forecast …

Dissecting Trypanosome Metabolism By Discovering Glycolytic Inhibitors, Drug Targets, And Glycosomal Ph Regulation, Daniel Hale Call

Theses and Dissertations

Trypanosoma brucei, the causative agent of African trypanosomiasis, and its relatives Trypanosoma cruzi and several Leishmania species belong to a class of protozoa called kinetoplastids that cause a significant health burden in tropical and semitropical countries across the world. While an improved therapy was recently approved for African trypanosomiasis, the therapies available to treat infections caused by T. cruzi and Leishmania spp. remain relatively poor. Improving our understanding of T. brucei metabolism can inform on metabolism of its relatives. The purpose of the research presented in this dissertation was to develop novel tools and methods to study metabolism in T. …

A Case Study Of The Design Of The Developmental Mathematics Corequisite Courses At Arkansas’ Public Two-Year Colleges, Jean Anne Swillum

Theses and Dissertations

Students determined to be underprepared for college-level mathematics would be enrolled in a sequence of developmental mathematics courses before taking their college-level mathematics course. Students who started in the lowest level of developmental mathematics had a twenty percent chance of completing their college-level mathematics credits (Bailey et al., 2010). Two innovative approaches were implemented to assist students with completing their college-level mathematics course. First, creating mathematics pathways courses aligned with student’s degree plans. Second, implementing developmental mathematics corequisite courses supporting the mathematics pathways courses. Thus, reducing the time it took an underprepared mathematics student to complete their college-level mathematics requirement. …

Hospital Provider Knowledge Of Behavioral Function And Management Of Severe Behavior For Patients With Autism, Giovanna Salvatore Devito

Theses and Dissertations

Hospital patients with autism spectrum disorder (ASD) may engage in various topographies of severe behavior, with higher rates of restraint implemented than for their neurotypical counterparts. Qualitative research suggests that physician knowledge of function-based intervention is limited. Multidisciplinary behavior management teams were developed to decrease restraint across general hospital patients. In Study 1, the research team developed the Knowledge of Behavioral Function (KoBF) survey measure, using an iterative user-centered development process and administered the measure to multidisciplinary physicians and trainees. Results indicated low knowledge of behavioral function, with a mean percent correct of 66.60% on close-ended survey items and 14% …

Exploring A Tailored Approach For Coordinated Early Intervening Services ( Ceis ) Designed To Address Struggling General Education Students Targeted For Special Education, Denise Lynch

Theses and Dissertations

This quantitative causal-comparative study examined whether early recuperativeDepartment of Education (DOE) Coordinated Early Intervening Services (CEIS) could significantly impact the number of underperforming general education students targeted for special education services resulting from not meeting Math and Reading grade-level state standards. Approximately 1400+ students were randomly selected from several elementary, middle, and high schools and enrolled for four years in CEIS in the Equliebeh School District. This study's findings were generated in response to several research questions that provided valuable insights into CEIS factors that impacted students' academic performance within the context of its programming. For instance, although some data …

Analysis And Evaluation Of Different Transformer Architectures For The Protein Sequence Representation And The Corresponding Hypothetical Applications, Mary Mao

Theses and Dissertations

This project is to investigate and assess several Transformer topologies for the modeling of protein sequences and their corresponding uses. Each major model for the protein sequence representations is inspected with its mathematical theory and analyzed for the different performance of the models with various validation repositories.

A Spatial Decision Support System For Rent Estimation Of Retail Spaces In Manhattan Using Geographically Weighted Regression And Spatial Regression, Andie M. Migden Miller

Theses and Dissertations

This report outlines an automated, three-phase Spatial Decision Support System that creates models to estimate rent of retail spaces across Manhattan. First, enrich data with predictors. Second, optimize spatially aware neighborhood-level models by combining GWR, spatial regression, and non-spatial regression. Finally, visualize results in an Esri-based WebApp.

Land Surface Temperature Change In New York City, 1985-2023: A Historical Analysis, Andrew Kittredge

Theses and Dissertations

Intra-urban land surface temperature change is not well studied outside of a land use land cover change perspective. To address this research gap, this thesis studied the effect of biophysical change and recent development on land surface temperature (LST) change in New York City from 1985 to 2023. Mean summer values of land surface temperature, transformed difference vegetation index (TDVI), and albedo were computed for New York City census tracts during 1985 – 1994 and 2015 – 2023, along with measures of development activity since 2015. A spatial Durbin error model (R²: 0.939, RMSE: 0.538°C) significantly related TDVI …

Oblique, Edward Kijowski

Theses and Dissertations

Oblique is a multi-sensory art installation that provides a story of fragmentation in sound and light rendered by an obtuse hexagon arrangement of speakers and associated lighting prompts. The oblique direction of the soundwaves creates sonic sculpturing that propels listeners into an active state.

Reflections Of Little Red Dot: An Interactive Mixed Reality Archival Experience, Chloé Lee

Theses and Dissertations

It has been nearly a decade since I last visited Singapore, a place I am connected to yet an outsider. Reflections of Little Red Dot is a mixed-reality experience that animates my archive of drawings, videos, and 3D imagery from everyday Singaporeans in 2015, the year their country celebrated its 50th birthday.

Walking through this liminal mixed reality space, we hear how citizens are personally affected by the rapidly developing landscape and erasure of personal and historical sites of significance while reflecting on our collective agency to shape the future of our environments. We are invited into homes where loved …

Conceptual Representation And Schemas: Perceived Gender Differences Among Kinds And Shared Properties, Kathryn G. Johnson

Theses and Dissertations

Schemas are modes of categorization containing associations between kinds and their related properties. Research suggests sex-linked properties possess principled differences between the sexes. The present study’s results suggest that non-sex-linked properties also possess principled differences, which were more prevalent among properties with principled rather than causal connections to a kind.

The Set Falls Apart, Thomas F. Tait

Theses and Dissertations

Using systems, puppets, and reappropriated technologies as central features of my practice, in my work I explore allegorical connections and cross-affiliations between otherwise separate ontological categories. In this text, I draw on sources such as affect theory, science fiction, theater, and the uncanny, to consider our affectual relationship to the nonhuman.

Adaptive Solutions For Improving The Quality Of Mobile User Experiences, Meena V

Theses and Dissertations

Nowadays, mobile applications have drawn a lot of attention as they bring computational and storage resources close to consumers globally through high-speed networks. Applications such as the medical microscope, 2D barcode reader, environmental sensor(s), mobile security and authenticator, vehicle remote controller, and IoT-based synchronizer come pre- applications are resource-intensive, as it performs computation(s) by utilizing diverse services like location, app-tracking, networking, camera, calendar, contacts, Bluetooth, etc. for each user activity. Parallel execution of such intense services might utilize the utmost memory and CPU of the mobile device which in turn degrades the overall Quality of Experience (QoE). This ultimately ends …

Trajectories Of Depression Severity In The First Semester Of College, Nicole A. Kelso

Theses and Dissertations

Depression is a major public health concern among students in higher education. Prior work suggests that depressive symptoms increase during the transition to college. Transfer students face unique challenges during the transition to a new academic institution that may make them particularly vulnerable. There is a critical need to expand prevention efforts. Research that improves identification of students at greatest risk for developing impairing depressive symptoms, and etiological processes contributing to depressive symptoms could aid in the provision of limited prevention resources. Furthermore, longitudinal research tracking symptom trajectories during the transition to college could help inform the timing of preventive …

The Olmsted Fault, Southernmost Illinois: A Key To Understanding Seismic Hazard In The Northern New Madrid Seismic Zone, Christopher E. Bexfield

Theses and Dissertations

The northernmost extent of the New Madrid seismic zone in the central USA has been investigated using an integrated approach involving both compressional-wave (P) and horizontally polarized-wave (SH) seismic reflection and regional and dedicated borehole geophysical information in order to assess seismic hazard and risk. Our study area, centered around southernmost Illinois and western Kentucky, USA, represents an area of concentrated facilities (e.g., lock and dam sites and chemical plants on the Ohio River near its confluence with the Mississippi River) as well as an area of high potential soil amplification due to earthquake shaking. Integrated high-resolution seismic reflection profiles …

Using Efficacious Content Area Literacy Practices To Support Student Improvement And Perception Of Self-Efficacy, Christine Mccabe

Theses and Dissertations

This thesis examines how students’ self-efficacy, confidence, and motivation change when students use content area literacy practices in math. This study was guided by the affective theories of Bandura, Maslow, and Guthrie & Wigfield. This study used qualitative research, focusing on collecting data through anecdotal evidence, student self-evaluation surveys, student journal responses, and a teacher research journal. Throughout the six week study, students participated in lessons focused on improving self-efficacy, confidence and motivation. Additionally, students learned to make connections between math and literacy through math literacy tasks, such as numberless word problems. Following the study, data was analyzed through triangulation …

Career Technical Education: Perceptions Of Medical Career Pathway Students Regarding Preparation For Post Secondary Goals, Charles Russel Dalusong

Theses and Dissertations

Career technical education (CTE) has evolved markedly over the past century to provide a viable avenue for high school students who may seek an alternative and successful academic path that leads to a well-paid future career in the workforce.Recent studies have found that Career and Technology Education can lower dropout rates among high school students (Stone and Lewis, 2012). Students that are enrolled in Career and Technical Education are exposed to a plethora of career opportunities that they may not be cognizant of. . . . (Smith, 2015, p. ii) If high-quality career and technical education (CTE) makes it possible …

Stem Teacher Shortage In American Schools: A Case Study Exploring The Recruitment Of Stem Majors Into Teacher Education Programs, Adekunle Lawal

Theses and Dissertations

There has been a STEM (science, technology, engineering, and mathematics) teacher shortage in K-12 schools across the United States (Klassen et al., 2021; Luft et al., 2005). To help provide a possible solution to the nationwide STEM teacher shortage, this study investigated the factors that influence STEM majors to change careers from STEM disciplines to teaching. In the current study, six American STEM teachers who have switched careers from the STEM profession to the teaching field were interviewed to find out the factors that led them to change careers; and how schools of education could use these factors in creating …

Examining The Shared Knowledge And Collaboration When Working With Students With Sensory Disabilities, Lacey Jo Long

Theses and Dissertations

The purpose of this study was to explore the shared knowledge and collaboration between special education and itinerant teachers working with students with sensory disabilities (i.e., teachers of students with visual impairments, teachers of the deaf/hard of hearing, and teachers of students who are deafblind). This study addressed the following research questions: What do special education and itinerant teachers need to know about sensory disabilities? How does this shared knowledge affect the collaboration of special education and itinerant teachers? The study was conducted using an anonymous online survey of special education and itinerant teachers serving students with sensory disabilities, including …

A Statistical Model For The Surface Tension Of Microdroplet Surfactants And Multicomponent Mixtures, Douglas Mohr

Theses and Dissertations

The effects atmospheric aerosols have on climate are not fully understood due to the limited knowledge of the interaction between aerosols and clouds. This interaction, known as the indirect effect of aerosols, is an area of interest within the field of atmospheric science. The presence of surfactants in the atmosphere due to natural and anthropogenic sources is known to negatively affect cloud formation, and is a contributor to the indirect effect. Quantifying how surfactants affect atmospheric aerosols will improve the understanding of the indirect effect. This work explores a statistically mechanically derived surface tension model for surfactant aqueous solutions, which …

Using An Airship Design To Extend A Small Uncrewed Aircraft Flight Endurance, Joseph Reilly

Theses and Dissertations

One limitation of uncrewed aircraft is being unable to fly as long as needed for some operations, such as linear inspection. This research explores the flight endurance of an uncrewed aircraft using airship design. It investigates the benefits of using an airship design to increase the efficiency and extension of the flight of a small, uncrewed aerial system (sUAS). Thus, it is crucial to find ways to augment flight endurance. Two different airframes were built, and flight tested using a lifting gas to provide the lifting force and vectored thrust needed to move. Flight testing captured time in the air …