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Evaluating Nonlinear Relationships In Sem Models: An Example Of Parameter Estimation And Stability Using Expectancy Value Theory, Steven G. Barth

Theses and Dissertations

In structural equation modeling, relationships between exogenous and endogenous variables are often assumed to be linear though that is not a requirement. A recent trend in modeling latent interactions and moderations has stimulated further inquiry into nonlinear relationships and the analysis techniques associated with those types of models. However, rarely do investigators specify other potential nonlinear relationships such as quadratic relationships. This study explores the potential for quadratic relationships within Expectancy Value Theory when p the impact of high school students’ motivational beliefs on their pursuit of STEM-related activities. Using the High School Longitudinal Survey as a source of information, …

On The Use Of Cfd Modeling And Analytic Methods To Describe Pressure Drop In Highly Dense Structured Adsorbents In Gas Separation Processes And Fundamentals Of Adsorption, Ryan Timothy Sanders

Theses and Dissertations

The scope of this work can be divided into two main thrusts on topics found within adsorption. The first, and primary, topic is the use of CFD and analytical modeling to describe the flow of gas through a parallel, structured adsorbent channel which is described in Chapters 1 and 2. Chapter 1 establishes a non-experimental methodology based on using a 3D Navier-Stokes (NS) computational fluid dynamics (CFD) model in lieu of experiments, for developing 1D axial pressure drop correlations for structured adsorbents with parallel channels. Chapter 2 utilizes the methodology established in Chapter 1 in order to develop a new …

Effects Of A Classroom Cognitive Apprenticeship On Scientific Reasoning, Student Agency, And Biology Self-Efficacy On Students In High School Biology, Anne Morris Byford

Theses and Dissertations

Students entering high school often bring misconceptions about the nature of science and experimentation with them from middle school. Many also bring a belief that they are not a “science kid” and, therefore, cannot be a strong student in Biology. This belief can lead to a lack of self-efficacy and of student agency in the classroom. Exposure to authentic research experiences has been shown to increase in self-efficacy and scientific reasoning. Typical research experiences have been limited to summers, specialized after school programs and, in many cases, honors students. To circumvent the unequitable access to these experiences and to determine …

Electronic Structure Investigation Of Photoswitch-Embedded Organic Frameworks And External Electric Field Effects On Carbon Dioxide, Austin Hill

Theses and Dissertations

Metal- and Covalent-Organic Frameworks (MOFs and COFs, respectively) are chemically versatile systems that have diverse applications, ranging from drug delivery to energy storage. This versatility is due to the highly tunable nature of organic frameworks, which utilize metal clusters, chemically diverse metals, and organic ligands. Researchers have recently demonstrated how MOFs and COFs can be remotely tuned through the use of photochromic organic linkers and light (Martin, et al., 2022). The implications of these findings are significant and have numerous applications, primarily in optical switching and energy storage. However, the photochromic mechanism within the organic framework must be investigated, which …

Impact Of Equitable Grading Practices On Student Outcomes And Biology Self-Efficacy In A Ninth Grade Biology Class, Laura Boyle

Theses and Dissertations

This action research study, set in a midwestern high school in the United States, was designed to investigate the impact of implementing equitable grading practices in a first semester freshman biology course. Many grading practices commonly used in classrooms in the United States are subjective, can be used to maintain compliance in the classroom, and do not accurately report what students know and can do. Ideas from Critical Race Theory and Bandura’s Self-Efficacy Theory guided this study. Qualitative and quantitative data were collected through pre and post self-efficacy surveys, grading surveys, and semi-structured student interviews, along with quantitative grade data …

Global Well-Posedness Of Nonlocal Differential Equations Arising From Traffic Flow, Thomas Joseph Hamori

Theses and Dissertations

Macroscopic traffic flow models describe the evolution of a function ρ(t, x), which represents the traffic density at time t and location x according to a differential equation (typically a conservation law). Numerous models have been introduced over the years which capture the phenomenon of shock formation in which the solution develops a discontinuity. This presents difficulties from the standpoint of mathematical analysis, necessitating the consideration of weak solutions. At the same time, this undesirable mathematical behavior corresponds to unsafe driving conditions on real roadways, in which the heaviness of traffic may vary abruptly and dramatically. This thesis introduces and …

Assessing Multi-Annual Phytoplankton Community Compositions And Biomass Across Tidal Creek And Open Water Estuarine Habitats In South Carolina, Shannon Elizabeth Powers

Theses and Dissertations

The urbanization of coastal environments in recent decades has caused an accelerating increase in nutrient-rich runoff from the landscape. The presence of these excess nutrients in the aquatic environment can result in degradation of water quality and harmful algal blooms. In South Carolina (SC), coastal development continues to threaten the resiliency of salt marsh estuaries, especially in combination with other stressors like climate change and sea level rise. Estuaries are important nurseries and habitats for fisheries and ecotourism. The South Carolina Estuarine and Coastal Assessment Program (SCECAP) is an ongoing monitoring program that assesses the habitat condition along the coast …

On Parallelization Of Graph Algorithms, Performance Modelling And Autonomous 3d Printable Object Synthesis, Shams-Ul-Haq Syed

Theses and Dissertations

The degree of hardware level parallelism offered by today’s GPU architecture makes it ideal for problem domains with massive inherent parallelism potential, fields such as computer vision, image processing, graph theory and graph computations. We have identified three problem areas for purpose of this research dissertation, under the umbrella of performance improvement by harnessing the power of GPUs for novel applications. The first area is concerned with k-vertex connectivity in graph theory, the second area deals performance evaluation using extended roofline models for GPU parallel applications and finally the third problem area is related to synthesis 3D printable objects from …

Experimental And Computational Understanding Of Solid Oxide Iron Air Battery Performance, Chaitali Morey

Theses and Dissertations

Long-duration energy storage (LDES) (10+ hours) is considered a key technical solution for a widespread penetration of renewable energy into the utility market. However, the currently available storage technologies are limited to less than 10 hours for cost reasons. The benchmark Li-ion battery technology would be economically prohibitive if the storage time goes beyond 4 hours. Therefore, developing new low-cost LDES-compatible battery technologies is highly desirable. A solid oxide iron air battery (SOIAB) has been developed which consists of a reversible solid oxide cell (RSOC) and energy storage unit (ESU) of an iron bed. This battery is considered a promising …

The Effectiveness Of Equivalence-Based Instruction On Time-Telling Skills In Children With Moderate Developmental Disabilities Including Autism Spectrum Disorder And Intellectual Disability, Rongzhi Li

Theses and Dissertations

The purpose of this study was to evaluate the effectiveness of equivalence-based instruction (EBI) on teaching time-telling skills to children with moderate developmental disabilities including autism spectrum disorder (ASD) and intellectual disability. Three children with ASD or intellectual disability participated in the study. The experiment was conducted using a concurrent multiple baseline design across subjects. During the acquisition training, each participant was taught 24 discrimination relations including matching 12 picture analog clock faces and 12 printed digital clocks to their dictated times. After the training, the participants were assessed to see whether their visual-visual responses (transitivity relations) and oral naming …

Molecular Rotors For Quantifying Kinetic Effects Of Stabilizing Non-Covalent Interactions, Binzhou Lin

Theses and Dissertations

This thesis describes the development of molecular machines as analytical instruments to measure the strength of non-covalent interactions and to test hypotheses of reaction mechanisms. The first chapter is a review of molecular rotors. The second chapter presents the development of a molecular rotor that can be controlled using electrostatic interactions. Previous examples have used electrostatic interactions to slow down or inhibit molecular motion. Our system is activated and sped up using electrostatic interactions. The third and fourth chapters describe the application of molecular rotors designed to experimentally measure the strength and stability trends for non-covalent pnictogen and chalcogen interactions. …

Stem Identity In African American Middle School Students: A Phenomenological Study, Amara L. Alexander

Theses and Dissertations

Using a phenomenological approach, this action research study explored the influence of culturally sustaining teaching practices (Ladson-Billings, 2014; Paris 2012, 2021) to impact African American students STEM identity (Collins & Roberson, 2020). Qualitative data were generated through interviews with students, practitioner reflective notes, and classroom observations during the intervention. Analysis and interpretation of the data indicated student- participants had positive experiences during the intervention and the culturally sustaining STEM lessons positively impacted African American middle school students STEM identity. The implications of these findings for STEM curriculum writers, STEM education and STEM educators, particularly those in K-12 education.

Statistical Inference Based On Elliptically Symmetric Distributions For Directional Data, Zehao Yu

Theses and Dissertations

Directional data arise in many scientific fields such as meteorology, oceanography, geology, zoology, and biomechanics. Geometrically, directional data lie in a spherical space. Although not in a spherical space, compositional data, such as microbiome data, can be mapped from a simplex to a spherical space via the component-wise square-root transformation. Other examples where compositional data emerge as a subject of interest include compositions of minerals in rocks, compositions of chemical mixtures, investment portfolios, and demographic composition of a population. This dissertation aims to develop inference procedures for analyzing directional data in general initially, with later focus shifted to the transformed …

Feature Engineering For Grain Boundaries And Other Variable-Sized Atom Clusters, C. Braxton Owens

Theses and Dissertations

Obtaining microscopic structure-property relationships for grain boundaries are challenging because of the complex atomic structures that underlie their behavior. This has led to recent efforts to obtain these relationships with machine learning, but representing a grain boundary structure in a manner suitable for machine learning is not a trivial task. There are three key steps common to property prediction in grain boundaries and other variable-sized atom clustered structures. These are: (1) describe the atomic structure as a feature matrix, (2) transform the variable-sized feature matrices of different structures to a fixed length common to all structures, and (3) apply machine …

Wind-Carved Wonders: An Aerial Study Of Yardangs In The Puna, Argentina Using Drone And Satellite Imagery, Derek Gordon Ashliman

Theses and Dissertations

Yardangs, elongated landforms sculpted by wind erosion, are prominent features in the Campo de Piedra Pomez (CPP) region of the Puna-Altiplano Plateau, Argentina. This study explores their formation and evolution through the examination of a 6 km by 0.5 km area captured in 2019 and a 5 km by 0.5 km area in 2024. High-resolution drone imagery and satellite data were employed to classify and quantify yardangs, gravel, and underlying bedrock across a vast study area. The research reveals a variation in yardang distribution and morphology from northwest (windward) to southeast (leeward), noting a significant decrease in yardang and bedrock …

Dynamics Of Dissolved And Particulate Trace Metals In A Snowmelt-Dominated Stream, Provo River, Utah, Usa, Kendra Louise Caskey

Theses and Dissertations

Trace element concentrations vary substantially during snowmelt runoff, with changes in the dissolved versus particulate fractions potentially impacting their movement at the catchment scale. To investigate trace element behavior in a snowmelt dominated stream, we measured concentrations in different size fractions in the Provo River (northern Utah, USA). We sampled the river at three locations during water years 2016-2018 and 2021-2023 for trace metal and major ion concentrations. During the final year, we collected three fractions (unfiltered, <0.45 µm filtered, and <0.22 µm filtered) for trace metal chemistry and calculated the particulate concentration as the difference between the unfiltered and 0.45 µm fraction. Stream measurements included pH, discharge, turbidity, and fluorescent dissolved organic matter (fDOM). We also sampled water sources (soil water, ephemeral streams, and snowpack) to compare trace metal concentrations across the watershed with the stream. Trace metal (Al, Be, Fe, Pb) and rare earth element (REE +Y) concentrations had the highest particulate and dissolved concentrations during snowmelt runoff. In contrast, major cations were primarily found in the dissolved fraction with lowest concentrations during snowmelt runoff. Major cation and particulate metal concentrations increased from upstream to downstream. The increased trace metal and REE + Y concentrations during snowmelt relative to baseflow may be explained by increased discharge and associated increased turbidity and fDOM. A comparison with water sources suggests that dissolved and particulate trace metals in the stream are sourced from flushed soil water, as trace metal transport through the watershed is facilitated by suspended sediment and dissolved organic matter. For most of the trace metals and REE +Y, concentrations were similar in the <0.45 µm and <0.22 µm fractions. Yet Al tended to have higher concentrations in the <0.45 µm fraction, suggesting a colloidal form of Al between 0.22 µm and 0.45 µm may exist. Differences from upstream to downstream may be related to changes in pH, from ~7 at the upper site to ~8 at the lower sites, which would change sorption capacity, saturation indices, or speciation. Our study demonstrates that trace metal concentrations are variable during snowmelt as the metals interact with suspended particles or dissolved organic matter and are influenced by changing water chemistry, with implications for understanding water quality impairments in snowmelt-dominated streams.

Deep Learning For Source Localization In A Laboratory Tank, Corey Emerson Dobbs

Theses and Dissertations

Deep learning has been applied to underwater acoustics problems in many forms. One difficulty in applying deep learning techniques to ocean acoustics is the spatially and temporally varying environmental properties. Another challenge is the lack of labeled data for training large networks. The overall goal of this work is to develop deep learning approaches for source localization that can be adaptable to different conditions. In this work, a convolutional neural network was trained on acoustic data measured in a water tank, while the water was at room temperature, to predict source-receiver range. Tests were done to ascertain ideal quantities of …

Linking Geospatial Trends And Geochemical Fingerprints To Anthropogenic Phosphorus Dust Deposition In Subalpine Soils, Austen Michael Lambert

Theses and Dissertations

This study shows that fugitive emissions associated with the surface mining of phosphate rock are a significant phosphorus (P) source to surface soils in northeastern Utah. Phosphorus is a nonrenewable resource essential for all life. Anthropogenic alterations to the P-cycle have led to widespread P pollution, and the unsustainable management of P has led to the threat of global depletion of P resources. Thus, accounting for both natural and anthropogenic flow paths of P is essential for the conservation and pollution reduction of P. One such source of human alteration to the P-cycle is the mining of phosphate rock. Mining, …

The Cofactor Matrix For Optimized Normal Transformations & Real-Time Caustics And Refractions Using Signed Distance Fields, Dane William Christensen

Theses and Dissertations

This thesis contains two distinct manuscripts both focused on real-time rendering research; an abstract for each is provided: 1. We survey methods for mapping normal vectors to a transformed surface with emphasis on the cofactor matrix form. We demonstrate that the cofactor matrix uniquely and correctly supports matrix transformations that are rank deficient or have negative determinants, while also generalizing to operations such as rotation, scaling, translation, and shearing. We derive and demonstrate the completeness of this new convention in contrast to other approaches, while also establishing its computational efficiency benefits. 2. We present SDF volumes as an efficient datastructure …

Killers That Once Were Humans: Reading The Role Of Modern Law Via Instrumental Rationality, Momen Abdelbari Hassan

Theses and Dissertations

For Max Weber, the process of modernization is the process of rationalization in which it includes every realm in our modern life, such as the economy, science, organization, education, and law. However, this kind of rationalization has created coercive and inhumane conditions because rationalization has converted to being instrumental (value-free) without regard to any transcendental or moral values. The inhumane paradigm has become the only fate of our world. The vision needs rational domination to be achieved through formal rational law. Modern law, along with bureaucratization, has paved the road to rational political domination. This kind of domination captures human …

A Sensitivity Equation Framework For Parameter Estimation In Dynamical Systems, Joshua Newey

Theses and Dissertations

We present a new framework for understanding parameter estimation in dynamical systems. The approach is developed within the modeling approach of continuous data assimilation. We outline the basic assumptions that lead to our derivation. Under these assumptions we show that the parameter estimation turns into a finite dimensional nonlinear optimization problem. We show that our derivation reproduces and extends the algorithm originally developed in [9]. We then implement these methods in three example systems: the Lorenz '63 model, the two-layer Lorenz '96 model, and the Kuramoto Sivashinsky equation. So as to remain sufficiently general, our derivations are largely formal; we …

Tools For Planning Multi-Axis Vibration Qualification Tests, Marcus Edward Behling

Theses and Dissertations

Vibration qualification testing is necessary to ensure that components will endure vibration-induced damage in flight. Multi-axis tests have shown the potential for improvement over single-axis tests, though they require increased planning. This work focuses on planning three critical aspects of these tests: the amount of operational next assembly to include in the test, the size of shakers to use, and the number of shakers to use. Next assembly selection is studied by varying the amount of next assembly included in the lab test, performing physical tests, and comparing the accuracy of environment reconstruction in each test. In doing so, a …

Zno Based Chemiresistive Sensor For Ammonia Detection, Anna Thomas

Theses and Dissertations

This work aims on the development of nanostructured sensing elements based on ZnO for detecting ammonia, specifically designed for applications in poultry and farm fields. To achieve this objective, we prepared sensing elements, including ZnO, CuO, WO3, NiO, ZnO/CuO, ZnO/WO3, ZnO/NiO, and rGO/ZnO, using the spray pyrolysis technique. Structural, morphological, and compositional analyses were studied using X-ray Diffraction (XRD), Field Emission Microscope (FESEM), and X-ray Photoelectron Spectroscopy (XPS), respectively. The vapour/gas detection studies of fabricated sensing elements were carried out in a home built sensing chamber.

The single oxides, ZnO, CuO, WO3, demonstrated ammonia detection in the range of 5-100 …

Optimal Navigation, Control And Simulation Of Electrified And Unmanned Ground Vehicles With Bio-Inspired And Optimization Approaches, Amine Taoudi

Theses and Dissertations

In recent years, significant progress has been made in autonomous robotics and the electrification of transportation, highlighting the growing importance of automation in daily life. Ensuring the safety and sustainability of automated systems necessitates the integration of intelligent algorithms capable of making astute decisions in uncertain circumstances. Autonomous robots possess considerable potential for efficiently performing intricate tasks, but this potential can only be unlocked through intelligent algorithms. Moreover, enhancing the energy efficiency of transportation systems yields extensive benefits for the environment, economy, and society at large. Addressing the urgent challenges of climate change and resource depletion necessitates prioritizing energy efficiency …

Contention Resolution With Collision Cost, Umesh Chandra Biswas

Theses and Dissertations

Contention resolution coordinates access to a shared communication channel divided into synchronized slots. For any fixed slot, a packet can be sent, leading to three outcomes: empty (no packet sent), successful (one packet sent), or collision (multiple packets sent). Each slot provides ternary feedback: empty, successful, or collision. Much of the prior work has mainly focused on optimizing the makespan, the number of slots needed for all packets to succeed. However, in many modern systems, collisions also incur time costs, which existing algorithms do not address. In this thesis, we design and analyze a randomized contention-resolution algorithm, Collision-Evasion Backoff, that …

Enhancing Afm Particle Analysis And Shape Factor Identification With Machine Learning, William David Mckelvey

Theses and Dissertations

Through enhancing aerosol particle measurement accuracy by determining particle shape factors using Atomic Force Microscopy (AFM) combined with machine learning techniques, this study aims to provide a methodology that will improve the precision of aerosol measurements and contribute to the development of more effective filtration technologies. Accurate shape factor measurement is crucial for devices such as the Scanning Mobility Particle Sizer (SMPS), which often assume spherical particles of uniform density. By identifying and analyzing particles in AFM scans using machine learning techniques, this research provides a better understanding of shape factors, improving the quality of aerosol measurements. These advancements contribute …

Special Educators’ Attrition And Retention In The Post-Covid-19 Era: A Systematic Literature Review, Brandi J. Young Sumrall

Theses and Dissertations

Special education faces persistent challenges with teacher attrition and retention in the ever-changing landscape of education post COVID-19. Using empirical research and scholarly insights, this systematic review investigates the factors that influence whether special educators choose to continue or leave their jobs following the pandemic. Central to this investigation are the aspects that influence educators' career decisions pre pandemic, such as job satisfaction, working conditions, support systems and opportunities for professional growth. Through this exploration, we gain insights into the reasons why special education teachers choose to stay or leave their roles. The study emphasizes the pressing need to address …

Forest Management In Changing Landscapes: Evaluating Hurricane Damage And Salvage Market Dynamics, Ian Pereira Sartorio

Theses and Dissertations

This dissertation comprises three interrelated studies exploring the effects of hurricanes on forestlands and the optimization of salvage logging practices. The first study examines land cover changes and salvage logging patterns following Hurricane Michael. It utilizes predictive models to identify key drivers of these changes, exploring the relative influence of storm intensity, forest vulnerability, and economic/operational factors. The second study builds upon these findings, focusing on the agent attribution for land cover change observations leveraging advanced remote sensing tools and relevant spatial data. By distinguishing between wind damage and salvage logging activities, it advances the understanding of post-hurricane land cover …

Alight, The Dead Of Night: Ascertaining The Collection And Use Of Nighttime Site Inventory In Landscape Architecture Professional Practice, Jacob Zachary Felkins

Theses and Dissertations

In landscape architecture, site inventory is a common precursor and perpetual informant of site design, toolkit development, and best management practices. Within inventory-specific texts, inventory is primarily geared, collected, and applied toward the daytime, and thusly, one might consider the bulk of inventory to be “daytime inventory” which pays greater heed to a diurnal humanity and lesser heed to the nocturnal world. With a greater attention to nighttime site conditions, we explored “nighttime inventory” through a series of primary considerations - nighttime lighting, light pollution, site ecology, and the night sky – along with several secondary considerations. We then surveyed …

Architecture Selection And Propulsion Supervisory Control Strategies For All-Wheel Drive Electric Vehicles (Evs), Jagdeo S. Singh

Theses and Dissertations

The automotive industry is shifting towards the development of electric vehicles (EVs) at a rapid pace with most manufacturers intending to be producing solely electric vehicles by 2050. This is due in large part to government regulations aiming to reduce emissions from the transportation sector. As a result, significant research is being conducted to advance the development of EV propulsion technology. This research explores two aspects of EV design: the analysis and selection of an efficient EV propulsion architecture, and the implementation and testing of an efficiency-based energy management strategy (EMS) for implementation on Mississippi State’s EcoCAR team vehicle for …