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 …

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 …

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 …

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 …

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, & …

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 …

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 …

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 …

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’ …

Multiphysics Assessment Of Accident Tolerant Fuel, Cladding, And Core Structural Material Concepts, Jacob Preston Gorton

Doctoral Dissertations

The severe accident at the Fukushima-Daiichi nuclear power plant in 2011 ignited a global research and development effort to replace traditionally-used materials in Light Water Reactors (LWRs) with Accident Tolerant Fuel (ATF) materials. These materials are intended to extend the coping time of nuclear power plants during severe accident scenarios, but must undergo thorough safety and performance evaluations before being implemented. Four ATF concepts are analyzed in this dissertation using state-of-the-art computer modeling tools: (1) iron-chromium-aluminum (FeCrAl) fuel rod cladding, (2) silicon carbide (SiC) fiber-reinforced, SiC matrix composite (SiC/SiC) boiling water reactor (BWR) channel boxes, (3) mixed thorium mononitride (ThN) …

Automated Intelligent Cueing Device To Improve Ambient Gait Behaviors For Patients With Parkinson's Disease, Nader Naghavi

Doctoral Dissertations

Freezing of gait (FoG) is a common motor dysfunction in individuals with Parkinson’s disease (PD). FoG impairs walking and is associated with increased fall risk. Although pharmacological treatments have shown promise during ON-medication periods, FoG remains difficult to treat during medication OFF state and in advanced stages of the disease. External cueing therapy in the forms of visual, auditory, and vibrotactile, has been effective in treating gait deviations. Intelligent (or on-demand) cueing devices are novel systems that analyze gait patterns in real-time and activate cues only at moments when specific gait alterations are detected. In this study we developed methods …

Engineered Carbon Materials With Nano-Graphitic Domains Derived From Lignin, Valerie Garcia Negron

Doctoral Dissertations

This work focuses on establishing a comprehensive understanding of lignin-derived materials as a function of carbonization with the goal of identifying processing-structure-property-performance relationships. A combination of modeling, statistical, and empirical materials characterization techniques are applied to lignin materials varying in feedstock source, extraction method, and processing conditions. The first part of this study evaluates the structure of carbon composite materials, possessing both crystalline and amorphous domains, using scattering techniques. One approach performs atomistic simulations of a proposed structure, from which the analogous scattering pattern can be obtained for validation. An alternative approach based on a hierarchical decomposition of the radial …

Mechanics Of The Solid-State Bonding Under Severe Thermomechanical Processes, Xue Wang

Doctoral Dissertations

Friction stir welding (FSW) has found increased applications in automotive and aerospace industries due to its advantages of solid-state bonding, no fusion and melting, and versatility in various working conditions and material combinations. The extent and quality of the solid-state bonding between workpieces in FSW is the ultimate outcome of their industrial applications. However, the relationship among processing parameters, material properties, and bonding extent and fidelity remains largely empirical, primarily because of the lack of the mechanistic understanding of (1) tool-workpiece frictional behavior, and (2) bonding formation and evolution.

In this dissertation, to study the underlying mechanism of tool-workpiece frictional …

Supplier Ranking System And Its Effect On The Reliability Of The Supply Chain, Farshad Rabib

Doctoral Dissertations

Today, due to the growing use of social media and an increase in the number of

A HITS with a solution in PageRank (Massimo, 2011) sharing their opinions globally, customers can review products and services in many novel ways. However, since most reviewers lack in-depth technical knowledge, the true picture concerning product quality remains unclear. Furthermore, although product defects may come from the supplier side, making it responsible for repair cost, it is ultimately the manufacturer whose name is damaged when such defects are revealed. In this context, we need to revisit the cost vs. quality equations. Observations of customer …

A Review Of Horticultural Therapy And Horticultural Therapy Education In The United States: Addressing Challenges And Opportunities, Derrick R. Stowell

Doctoral Dissertations

The Horticultural Therapy (HT) profession has been formally organized in the United States since 1973. Despite the long history of horticulture being used as therapy, the profession of HT in the United States has not advanced as quickly as other allied healthcare professions. This study will review the current challenges and opportunities for HT and HT education in the United States.

A qualitative study of the status of the profession was conducted to determine what challenges and opportunities the profession of HT currently has and how the profession can meet those challenges and opportunities. The study sample was recruited from …

Nonparametric Bayesian Deep Learning For Scientific Data Analysis, Devanshu Agrawal

Doctoral Dissertations

Deep learning (DL) has emerged as the leading paradigm for predictive modeling in a variety of domains, especially those involving large volumes of high-dimensional spatio-temporal data such as images and text. With the rise of big data in scientific and engineering problems, there is now considerable interest in the research and development of DL for scientific applications. The scientific domain, however, poses unique challenges for DL, including special emphasis on interpretability and robustness. In particular, a priority of the Department of Energy (DOE) is the research and development of probabilistic ML methods that are robust to overfitting and offer reliable …

Probing Structure, Function And Dynamics In Bacterial Primary And Secondary Transporter-Associated Binding Proteins, Shantanu Shukla

Doctoral Dissertations

Substrate binding proteins (SBPs) are ubiquitous in all life forms and have evolved to perform diverse physiological functions, such as in membrane transport, gene regulation, neurotransmission, and quorum sensing. It is quite astounding to observe such functional diversity among the SBPs even when they are restricted by their fold space. Therefore, the SBPs are an excellent set of proteins that can reveal how proteins evolution novel function in a structurally conserved/constrained fold. This study attempts to understand the phenomenon of affinity and specificity evolution in SBPs by combining a set of biochemical, biophysical, and structural studies on the SBPs involved …

Women In Science, Technology, Engineering And Mathematics (Stem): Pre-College And College Factors Of Success, Jada Russell

Doctoral Dissertations

Scholars have reported that the competitiveness and innovation of the United States’ workforce in Science, Technology, Engineering and Mathematics [STEM] fields are critical to maintaining our nation’s security and economic edge (Chen, 2009; Carlone & Johnson, 2007; Espinosa, 2011). Indeed, STEM is one of the fastest growing fields in the employment industry, according to the U.S. Department of Commerce (Langdon, et. al, 2011), and between 2008 and 2018, the number of STEM jobs is expected to increase 17%. Fostering learning pathways for all individuals interested in pursuing careers and education in STEM disciplines is necessary for us to meet the …

Rational Design Of Non-Noble Metal Intermetallic Compounds With Tunable Surface And Catalytic Chemistry Via Combined Computational And Experimental Method, Yuanjun Song

Doctoral Dissertations

This study focuses upon understanding and rationally tuning the surface reactivity towards C, H, and O of non-noble metal intermetallic compounds (IMCs) catalysts in olefin production and hydrocarbons reforming reactions. In these reactions, different degrees of surface reactivity towards C, H, and O are required to achieve high activity and selectivity as well as stability. A combined computational and experimental method was performed to build this understanding how to rationally design catalysts. Investigations based on quantum chemical calculations indicate surface reactivity towards C, H, and O is a function of element size of constituent elements as well as bulk and …

Development And Validation Of A Cross Correlation Function Based Indirect Flow Measurement Technique, Xiong Gao

Doctoral Dissertations

Nuclear Power Plants (NPPs) require the accurate measurement of mass flow rates. Advanced flow meters have been invented and widely applied in several current industries; however, the operation environment in nuclear power plants is especially harsh due to high temperature, high radiation and extremely corrosive conditions.. Several of the advanced reactor designs, such as liquid sodium pool reactors and integral small modular reactors, do not have conventional primary piping systems. These designs necessitate alternative methods to accurately measure primary flow.

Cross Correlation Function (CCF) flow estimation, which was proposed in the 1980s, can estimate the flow velocity indirectly without any …

Teaching Stories In Online Police Firearms Training Videos: Analysis Of Content And Messages Carried, Alan Alfred James Bailey

Doctoral Dissertations

Abstract

The purpose of this study is to identify teaching stories in freely available online police firearms training videos and examine the manifest or latent messages they may carry for a law enforcement audience. The literature recognizes that “well told stories have educational power” (Rae, 2016, p.2) and that adult educators traditionally use stories to teach (Clark & Rossiter, 2008) including some police academy trainers (Ford, 2003). However, there is less appreciation of story’s role in the informal learning setting of online videos that might influence the thinking and behavior of viewers. Randomly selected videos were analyzed to identify the …