Digital Commons Network^™

Novel Trinuclear Single-Site Titanosilicate With Targeted Connectivity: Synthesis, Characterization And Catalytic Properties In Selective Oxidation Of Olefins, Michael Charles Orick

Doctoral Dissertations

Catalysts are an essential component in the chemical industry converting raw materials into essential products. Transition metal catalysts, more specifically titanosilicates, are effective in the selective oxidation of olefins producing monomers and chemical intermediates used in many industrial applications. A major challenge in the catalysis community is developing synthetic methodologies that produce robust heterogeneous catalysts with isolated, single type of active sites with targeted connectivities to the support matrix.

The Barnes’ research group has developed a building block synthetic methodology that produces a single-site heterogeneous catalyst. This methodology uses a molecular building block and titanium (IV) precursors to create site …

The Design Discourse Of Professional Instructional Designers, Katherine L. Bevins

Doctoral Dissertations

The design discourse of professional instructional designers (IDs) exposes the inner workings of instructional design because collaboration is integral to instructional design practice. Despite the importance of collaboration, there has been little examination of the collaboration in Instructional Design and Technology (IDT). To examine IDs’ collaboration, I examined the design discourse of IDs in design meetings with clients through a content analysis of their discourse. Analysis revealed areas of design expertise that frequented those discussions. I collected audio recordings of five discussions between one or more IDs and a client. Overall, six IDs and five clients participated in this study. …

Soil Health Assessment For The Agroecosystems Of West Tennessee, Surendra Singh

Doctoral Dissertations

Soil health assessment is important for making informed sustainable management decisions in production systems. An established standardized method to quantify soil health is lacking and the validity of the existing methods across agroecoregions and cropping systems is not yet proven. Therefore, this study aims to evaluate the feasibility of widely discussed three soil health tests - Haney’s Soil Health Test (HSHT), Comprehensive Assessment of Soil Health (CASH), and Alabama Soil Health Index (ASHI) to assess soil health in diverse cropping systems of Tennessee. Since these approaches were originally developed for specific agroecoregions, we hypothesized that these tests are not sensitive …

Multiscale Simulations Of Polymeric Electrolytes For Electrochemical Devices, Xubo Luo

Doctoral Dissertations

Polymeric electrolytes are polymers containing the ionic moieties used for ion conduction in electrochemical devices. The strategic design of these materials requires the in-depth understanding of the relation between the molecular structure and the properties. This dissertation reports on computational simulations for two types of materials: hydrated anion exchange membranes (AEMs) for fuel cells and the polymerized ionic liquids (PolyILs). Various chemical structures were covered for systematic investigations.

For AEMs, the ion conducting channels or domains are essential for the efficient ion transport, and thus the morphology of the hydrated membrane is worthy of study. Dissipative particle dynamics simulations were …

Local Structure And Dynamic Studies Of Mixed Ch4-Co2 Gas Hydrates Via Computational Simulation And Neutron Scattering, Bernadette Rita Cladek

Doctoral Dissertations

Permeated throughout the ocean floor and arctic permafrost, natural gas hydrates contain an estimated 3000 trillion cubic meters, over three times that of traditional shale deposits, of CH₄ that is accessible for extraction. Gas hydrates are a crystal structure in which water molecules form a cage network, the host, through hydrogen bonds while trapping a guest molecule such as CH₄ in the cavities. These compounds form naturally where the appropriate low temperature and high pressure conditions occur. A promising and tested method of methane recovery is through exchange with CO₂, which energetically takes place of the …

The Lived Experiences Of Graduate Student Veterans Enrolled In Cacrep-Accredited Counseling Programs: A Transcendental Phenomenological Study, Gerald Spangler

Doctoral Dissertations

Student veterans (SVs)are a population of students studied extensively at the undergraduate level. These students possess military traits and characteristics that influence their academic experiences. Existing research focuses on these experiences to better understand and assist in fostering academic persistence. However, there is gap in literature that explores the lived experiences of graduate SVs. This literature is even more pronounced when narrowed to graduate SVs enrolled in Council for Accreditation of Counseling and Related Educational Programs (CACREP). Therefore, this study sought to address this gap and gain a better understanding of graduate SVs and their academic experiences that lead to …

Dynamic Neuromechanical Sets For Locomotion, Aravind Sundararajan

Doctoral Dissertations

Most biological systems employ multiple redundant actuators, which is a complicated problem of controls and analysis. Unless assumptions about how the brain and body work together, and assumptions about how the body prioritizes tasks are applied, it is not possible to find the actuator controls. The purpose of this research is to develop computational tools for the analysis of arbitrary musculoskeletal models that employ redundant actuators. Instead of relying primarily on optimization frameworks and numerical methods or task prioritization schemes used typically in biomechanics to find a singular solution for actuator controls, tools for feasible sets analysis are instead developed …

A Method For Developing And Testing Nuclear Reactor Systems With Space Applications And Improving Performance Of Heat Pipe Reactor Systems, David Duff Dixon

Doctoral Dissertations

The concept of using nuclear reactor technology in propulsion systems is nearly as old as nuclear reactors themselves. Numerous publications, many at very primitive conceptual levels, suggested nuclear propulsion in the 1940s. Since then, numerous attempts have been made to build and fly a nuclear rocket, yet there have been no such systems advanced to the point of a system test in more than half a century.

This dissertation presents an approach to reactor system development, a testing approach developed by the author that resulted in the operation of the world’s first heat pipe reactor system, and the world’s first …

Costs Of Protected Areas In The United States, Diane Le Bouille

Doctoral Dissertations

Protected areas, or land owned in fee by agencies and non-profits to further conservation goals, have traditionally been the go-to choice for conservation interests. The UN Environment World Conservation Monitoring Centre estimates that, currently, close to 15% of all terrestrial and inland water areas are protected. This figure falls short of the Aichi Biodiversity Target of 17% in 2020, that was added to the Convention on Biological Diversity by its 196 signatories in 2010. But as the Convention prepares to set new post-2020 targets, this percentage is expected to keep increasing. Although acquiring a parcel of land is only one …

Distributed Sensor Network Data Fusion For Nuclear Security Applications, Ian Robert Stewart

Doctoral Dissertations

Detecting, locating, and interdicting radiological materials out of regulatory control or that pose a threat to the general public remains a high national security priority. Conventional methods employed a radiation detection system to detect radiological materials and alert the appropriate authorities for interdiction procedures. More recently, the concept of operations has focused to deploying multiple radiation detection systems to detect and track radiological materials, providing more detail to aid end-users during the interdiction process. The research proposed in this document utilizes data from a distributed sensor network to detect and track radiation anomalies through a network. The primary original contributions …

Development Of (Α,N) Signatures As A Viable Safeguards Measurement For Electrochemical Reprocessing, Stephen N. Gilliam

Doctoral Dissertations

As interest grows in electrochemistry for material separations and reprocessing of nuclear fuel research and development into the safegaurdability of such a system is needed. Plutonium quantification via (α,n) neutrons within the electrorefiner vessel is examined as a potential alternative means to the traditional spontaneous fission tracking. An MCNP model of an Epi-Thermal Neutron Multiplicity counter was used in the calculation of curium from a sample of curium, plutonium, and eutectic salt. This and the multiplicity variable alpha, the ratio between (α,n) neutron and spontaneous fission, were then used to define the plutonium mass as it related to its (α,n) …

Computer Simulations Of Biological Systems: From Protein Dynamics To Drug Discovery, Rupesh Agarwal

Doctoral Dissertations

Computational biophysics methods such as molecular dynamics (MD) simulations are often used in combination with experimental techniques like neutron scattering, NMR, and FTIR to explore protein conformational landscapes. With the improvements in experimental techniques, there is also a need to continually optimize the MD forcefield parameters to make precise predictions that match experimental results. To complement many of these experiments, an accurate model of deuteration is frequently required, but has been elusive. In our work, we developed a novel method to capture isotope effects in classical MD simulations by re-parameterization of the bonded terms of the CHARMM forcefield using quantum …

Efficacy Of A Cycling Intervention With Pedal Reaction Force Augmented Feedback On Reducing Inter-Limb Asymmetries In Patients With Unilateral Total Knee Arthroplasty, Erik T. Hummer

Doctoral Dissertations

Fifteen patients with unilateral total knee arthroplasty (TKA) performed cycling at two workates (80 W and 100 W) and two walking conditions (preferred and fast speeds). Ten of these patients of TKA also participated in a short-term cycling intervention paired with visual augmented feedback of vertical pedal reaction forces for six sessions over two-three weeks. These ten patients of TKA participated in a 2^nd post-training testing session. Study One compared the knee joint biomechanics for all fifteen participants during stationary cycling to ascertain if any biomechanical asymmetries may be present. The replaced limbs displayed significantly lower peak knee extension …

Prevalence Of Rats And Rodent Borne Pathogens Across Post-Katrina New Orleans, Bruno Marco Ghersi

Doctoral Dissertations

Disasters are happening at an increasingly higher rate and intensity a trend that is expected to continue as more humans migrate to coastal urban areas. Disasters, and as importantly, disaster recovery can affect how native and pest populations will recover. My aim was to improve understanding of disease risk by evaluating the socioecological conditions that have shaped commensal rat recovery and distribution, as well as the pathogens they carry, across New Orleans after Hurricane Katrina. I first estimated relative abundance and distribution of commensal rats from rodent trapping conducted between mid-2014 and early-2017 across 96 sites in 10 areas of …

An Exploratory Study Of Varying Phenotypes Of Posttraumatic Stress Among A Comorbid Substance Misuse Population, Dennis Allen Donahue

Doctoral Dissertations

Objective: The purpose of this study was to explore differences in presentation of posttraumatic distress (PTD) that may represent different phenotypes, such as a possible cognitively-driven variant, in addition to those rooted in the prevailing conditioned-fear model. In conjunction, links to substance misuse and a purposeful selection bias for specific drugs-of-choice (DoC) based on phenotype variation were examined. Method: A convenience sample of inpatients in residential treatment for substance misuse who also endorsed posttraumatic distress following at least one previous traumatic experience (N = 177) completed self-report assessments and an in-person direct inquiry. Results: Hierarchical cluster analysis and ANOVA …

Extracting Detailed Metabolic Information And Connections From Mammalian Gut Microbiomes Via Metaproteomics, Jose A. Blakeley-Ruiz

Doctoral Dissertations

A diverse community of bacteria populates the mammalian gastrointestinal tract. These populations exist in a balance with the host assisting with key functions, particularly metabolism of intractable fibers and immune modulation. Disruption of this balance can lead to diseases such as infection, inflammatory bowel syndrome, and obesity. Common symptoms include chronic pain, chronic inflammation, and altered metabolism. Several taxonomic classifications of bacteria have been associated with these diseases, but Recent studies have indicated that these finding are not always statistically valid. An explanation for this is that microbial communities between individuals and even across time can vary substantially even when …

Factors Predicting Turnover Of International Science And Engineering Faculty At Us Research Universities, Lauren Longino Jacobs

Doctoral Dissertations

In today’s global knowledge-economy, US research universities seek to attract and retain the best and brightest faculty in the world to increase the university’s intellectual capital and compete on a global scale. Increasingly, universities hire talented international faculty to fulfill these needs, which is especially prevalent in the science and engineering fields (S&E). International faculty benefit US universities in areas of research and scholarship as well as increased diversity and internationalization of the campus, however, not all international S&E faculty are retained. In fact, higher turnover has been found among international S&E faculty than their domestic peers (Kim, Twombly, & …

Mixed-Precision Numerical Linear Algebra Algorithms: Integer Arithmetic Based Lu Factorization And Iterative Refinement For Hermitian Eigenvalue Problem, Yaohung Tsai

Doctoral Dissertations

Mixed-precision algorithms are a class of algorithms that uses low precision in part of the algorithm in order to save time and energy with less accurate computation and communication. These algorithms usually utilize iterative refinement processes to improve the approximate solution obtained from low precision to the accuracy we desire from doing all the computation in high precision. Due to the demand of deep learning applications, there are hardware developments offering different low-precision formats including half precision (FP16), Bfloat16 and integer operations for quantized integers, which uses integers with a shared scalar to represent a set of equally spaced numbers. …

The Strength Of Self: An Examination Of Self-Directed Learning And Self-Regulated Learning Among Master’S Students, Holley Marie Linkous

Doctoral Dissertations

There is a lack of understanding of the difference between self-directed learning and self-regulated learning. Though both theories have been found to be important learning processes for achieving learning goals, there is little evidence to identify how the two directly compare. Self-directed learning and self-regulated learning can both be defined as learning processes as well as a collection of characteristics of an individual (Brockett & Hiemstra, 1991; Efklides, 2011). There are metacognitive components to these learning processes (Saks & Leijen, 2014; Zimmerman & Moylan, 2009). It can benefit scholars to know how these two concepts within a structured, complex, high-demand, …

Laser-Induced Breakdown Spectroscopy And Plasmas Containing Cyanide, Christopher Matthew Helstern

Doctoral Dissertations

This dissertation focuses on laser-induced plasma of diatomic molecular cyanide. Optical breakdown plasma generation is produced by high-peak-power 1064 nm Q-switched nanosecond pulsed radiation. Laser-induced breakdown is performed on a 1:1 molar gas mixture of carbon dioxide and nitrogen held at a fixed pressure of 760 Torr, a 1:1 molar gas mixture of carbon dioxide and nitrogen held at a fixed pressure of 2069 Torr, and a flowing 1:1 molar gas mixture of carbon dioxide and nitrogen flowing at a rate of 100 mL per minute. Plasma shockwave measurements in laboratory air are shown to determine the shock front geometry …

More Than The Sum Of Their Parts: Building A Framework For Understanding Host-Microbe Interactions In Medicago Sativa, Katherine Mackenzie Moccia

Doctoral Dissertations

This dissertation seeks to understand plant-microbe interactions in the agriculturally relevant plant Medicago sativa from three distinct vantage points within microbiology. Within the plant microbiome, we examine how primer usage and the application of peptide nucleic acids impacts 16S and 18S rRNA gene sequencing. In doing so, we design a novel peptide nucleic acid, PNA, and test its impact using multiple primers and sequencing protocols. Once microbial sequencing methodology is established, we generate a synthetic consortium of bacterial isolates from M. sativa leaves and modulate nitrogen levels to better understand microbial structure. Drop out communities, where we remove one member …

Application Of Crowdsourced Data In Transportation Operations And Safety, Nima Hoseinzadeh

Doctoral Dissertations

Crowdsourcing refers to the acquisition of data from users who contribute their information via smartphone, social media, or the internet. In transportation systems, crowdsourcing turns users into real-time sensors, providing data on traffic speed, travel time, mile traveled, incidents, roadway conditions, weather severity, irregularities in traffic patterns, and hazards. These data can be collected actively or passively in quantitative or qualitative forms. With the emergence of smartphones and navigation apps, crowdsourced data are gaining increased attention in transportation. Crowdsourced data have advantages over traditional fixed-location sensors and camera monitoring: low implementation costs, extended geographic coverage, high resolution, real-time application, increased …

The Lived Resettlement Experience For Single Refugee Mothers From The Democratic Republic Of Congo, Lauren Michelle Mefford

Doctoral Dissertations

At least 72% of the 50,000 Congolese refugees resettled in the USA in the last 5 years are women and children. Many are single refugee mothers (SRM) disadvantaged by obstacles (i.e., childcare) that hinder them from becoming self-sufficient within the required timeframe post-resettlement. Published research on resettlement has focused general challenges, but an understanding of the unique needs and perspectives of SRMs is lacking. This phenomenological, qualitative study provides insight into the lived resettlement experience for SRMs from the Democratic of Congo (DRC). Participants (n=7) were recruited from a refugee resettlement agency in East Tennessee and partook in open-ended, unstructured …

An Investigation Of How Institutional And State Characteristics Influence Community College Award Rates, Jacob A. Kamer

Doctoral Dissertations

Community colleges are an essential element of the American postsecondary landscape and workforce preparation. In 2017, over six-million students, which represented roughly one-third of the total undergraduate enrollment in the United States, were enrolled in community colleges. In the past ten years, the importance of community colleges in the economic need for greater postsecondary credential attainment has been underscored by state policies and national initiatives. The wide variation in both the nature of community colleges and the students they serve makes examining the outcomes of these institutions difficult and oftentimes imprecise.

Assessing the performance of community colleges and determining what …

Design And Implementation Of An Isfet Sensor With Integration Of An On-Chip Processor, Shaghayegh Aslanzadeh

Doctoral Dissertations

Portable sensors are used in many applications. Among them, pH sensors are suitable for quantifying and identifying various analytes in real-time and doing so non-invasively. The analytes may have environmental impact such as in water quality monitoring. The analytes may also have biological impact such as monitoring cell culture or remote patient health assessment. CMOS based sensors are compact and enable low power consumption suitable for these portable applications.

This work reports on the development of a portable CMOS based pH sensor. The contributions of this dissertation are as follows. First, a differential pH sensor, with two different sized electrodes …

Multi-Layer Utilization Of Beamforming In Millimeter Wave Mimo Systems, Mustafa S. Aljumaily

Doctoral Dissertations

mmWave frequencies ranging between (30-300GHz) have been considered the perfect solution to the scarcity of bandwidth in the traditional sub-6GHz band and to the ever increasing demand of many emerging applications in today's era. 5G and beyond standards are all considering the mmWave as an essential part of there networks. Beamforming is one of the most important enabling technologies for the mmWave to compensate for the huge propagation lose of these frequencies compared to the sub-6GHz frequencies and to ensure better spatial and spectral utilization of the mmWave channel space. In this work, we tried to develop different techniques to …

Characterization Of A Digital Holography Diagnostic For In Situ Erosion Measurement Of Plasma-Facing Components In Fusion Devices, Cary Dean Smith

Doctoral Dissertations

Fusion energy devices, particularly tokamaks, face the challenge of interior surface damage occurring over time from the heat flux of the high-energy plasma they generate. The ability to monitor the rate of surface modification is therefore imperative, but to date no proven technique exists for real-time erosion measurement of planar regions of interest on plasma-facing components in fusion devices. In order to fill this diagnostic gap, a digital holography system has been established at ORNL [Oak Ridge National Laboratory] for the purpose of measuring the erosion effects of plasma-material interaction in situ.

The diagnostic has been designed with the …

Betwixt And Between: Qualitative Examinations Of Leaders’ Internal Processes Of Transition, Margaret M. Ritchie

Doctoral Dissertations

This study examines alternative forms of school governance from the personal perspectives of leaders, reflecting upon their transition through the organizational governance change. The effects of moving from a local governance authority to a five school multi-academy trust was both thrust upon the leaders who participated in this study as they, in turn, thrust the change upon others. This new vision of schooling rippled throughout the schools involved, the community in which the schools are located, and the greater local authority that did not embrace this change. The purpose of this qualitative study was to examine alternative forms of school …

3d Study Of Gas Hydrate Formation And Dissociation In Porous Media And Dem Modeling Of Granular Materials, Zaher Jarrar

Doctoral Dissertations

Natural methane gas hydrates availability and ongoing rise in demand for energy, motivated researchers to consider gas hydrates as a potential energy source. Production of methane from hydrate-bearing sediments requires hydrate dissociation for releasing mobile methane gas in sediments prior to gas production operations. Fines may migrate through or clog the pore space of sandy sediments depending on the geometry and topology of the pore space. This dissertation employs unique in situ experiments and techniques to gain a comprehensive understanding of the associated physical processes (such as fines migration, clogging and gas driven fracture) and validation of hydrate dissociation models’ …

Approaches To Studying Bacterial Biofilms In The Bioeconomy With Nanofabrication Techniques And Engineered Platforms., Michelle Caroline Halsted

Doctoral Dissertations

Studies that estimate more than 90% of bacteria subsist in a biofilm state to survive environmental stressors. These biofilms persist on man-made and natural surfaces, and examples of the rich biofilm diversity extends from the roots of bioenergy crops to electroactive biofilms in bioelectrochemical reactors. Efforts to optimize microbial systems in the bioeconomy will benefit from an improved fundamental understanding of bacterial biofilms. An understanding of these microbial systems shows promise to increase crop yields with precision agriculture (e.g. biosynthetic fertilizer, microbial pesticides, and soil remediation) and increase commodity production yields in bioreactors. Yet conventional laboratory methods investigate these micron-scale …