Digital Commons Network^™

Fourier Transform Infrared Spectroscopy For The Measurement Of Gesn/(Si)Gesn, Solomon Opeyemi Ojo

Graduate Theses and Dissertations

Photoluminescence (PL) and Electroluminescence (EL) characterization techniques are important tools for studying the optical and electrical properties of (Si)GeSn. Light emission from these PL and EL measurements provides relevant information on material quality, bandgap energy, current density, and device efficiency. Prior to this work, the in-house PL set-up of this lab which involves the use of a commercially-obtained dispersive spectrometer was used for characterizing both GeSn thin film and fabricated devices, but these measurements were limited by issues bordering on low spectral resolution, spectral artifacts, and poor signal-to-noise ratio (SNR) thereby resulting in the possible loss of vital information and …

Optimizing Immersive Technology Condition For Measuring Consumer Perception And Acceptance Of Food Products, Shady Afrin Jeesan

Graduate Theses and Dissertations

Rapid advancement of immersive technologies is paving the way toward a new era in sensory and consumer science by enabling consumers to experience tasting of food samples in different environments, thus generating more realistic perception. However, little attention has been paid to developing a standardized and optimized methodology for conducting such sensory testing in an immersive environment. A variety of factors related to sensory testing in an immersive environment may significantly modulate consumer perception and acceptance of foods. Therefore, this thesis study aimed to optimize protocols related to sensory testing using immersive technology. In this thesis study, participants were asked …

Multiphoton Microscopy And Deep Learning Neural Networks For The Automated Quantification Of In Vivo, Label-Free Optical Biomarkers Of Skin Wound Healing, Jake D. Jones

Graduate Theses and Dissertations

Non-healing ulcerative wounds that occur frequently in diseases such as diabetes are challenging to diagnose and treat due to numerous possible etiologies and the variable efficacy of wound care products. With advanced age, skin wound healing is often delayed, leaving elderly patients at high risk for developing these chronic injuries. As it is challenging to discriminate age-related delays from disease-related chronicity, there is a critical need to develop new quantitative biomarkers that are sensitive to wound status. Multiphoton microscopy (MPM) techniques are well-suited for 3D imaging of epithelia and are capable of non-invasively detecting metabolic cofactors (NADH and FAD) without …

Conceptualizing Social Capital As Access To Social Network And Mobilization Of Network Resources: A Study Of Workplace Literacy Programs And Low-Income Somali Refugee Workers, Angela Uchechukwu Nwude

Graduate Theses and Dissertations

There is a substantial body of literature on the economic benefits of workplace literacy programs, and much less empirical studies on the social or non-economic outcomes of workplace literacy programs, particularly in the context of low-income refugee workers. Adopting a social network approach, this study examines the impact of workplace literacy programs on the social capital development of Somali refugee workers. Social capital can be defined as the network of relationships possessed by an individual or social group that facilitates their access to emotional, instrumental, or informational resources, essential for their daily survival, stability, or upward mobility. This study takes …

Applications Of Cathodoluminescence In Plasmonic Nanostructures And Ultrathin Inas Quantum Layers, Qigeng Yan

Graduate Theses and Dissertations

Due to the advanced focusing ability, characterization methods based on the electron-beam excitation have been broadly applied to investigate nanomaterials. Structural or compositional information is commonly acquired using electron microscopes. Moreover, taking advantage of the super spatial resolution of the focused electron beam, optical properties of nanomaterials can be also obtained. Herein, general concepts and processes of the interaction between electrons and materials are studied. Two specific optical nanomaterials, including plasmonic nanostructures and semiconductor quantum layers, are investigated by the cathodoluminescence (CL) measurement.

Surface plasmonic resonance can be generated when high-energy electrons strike the interface between the dielectric medium and …

Design And Evaluation Of High Power, High Efficiency And High Power Density Motor Drives For More Electric Aircrafts, Zhao Yuan

Graduate Theses and Dissertations

More-electric aircraft (MEA) is an attractive concept as it can reduce carbon dioxide emission, relieve fossil-fuel consumption, improve the overall efficiency of aircraft, and reduce the operational costs. However, it poses substantial challenges in designing a high-performance motor drive system for such applications. In the report of Aircraft Technology Roadmap to 2050, the propulsion converter is required to be ultra-high efficiency, high power density, and high reliability. Though the wide band-gap devices, such as the Silicon-carbide based Metal Oxide Silicon Field Effect (SiC-MOSFET), shows better switching performance and improved high-temperature performance compared to the silicon counterparts, applying it to the …

Effects Of Long-Term Variation In Temperature On Reproductive Phenology In A Population Of Eastern Bluebirds (Sialia Sialis), Paul Pleiman

Graduate Theses and Dissertations

This study investigates the relationship between multiple temperature variables, to include annual and pre-lay date temperatures with first-egg and mean first-egg lay dates of the eastern bluebird at the Warner Parks in Nashville, Tennessee, USA. Data is collected by citizen scientists for the Eastern Bluebird Nesting Box Project while visiting artificial nest boxes throughout the park and recording observations made during the breeding season. Temperature data is retrieved from the Northwest Alliance for Computational Science and Engineering’s Parameter-elevation Regressions on Independent Slopes Model (PRISM) Climate Group, based at Oregon State University. The analyses showed no correlation between annual or pre-lay …

Ppmexplorer: Using Information Retrieval, Computer Vision And Transfer Learning Methods To Index And Explore Images Of Pompeii, Cindy Roullet

Graduate Theses and Dissertations

In this dissertation, we present and analyze the technology used in the making of PPMExplorer: Search, Find, and Explore Pompeii. PPMExplorer is a software tool made with data extracted from the Pompei: Pitture e Mosaic (PPM) volumes. PPM is a valuable set of volumes containing 20,000 historical annotated images of the archaeological site of Pompeii, Italy accompanied by extensive captions. We transformed the volumes from paper, to digital, to searchable. PPMExplorer enables archaeologist researchers to conduct and check hypotheses on historical findings. We present a theory that such a concept is possible by leveraging computer generated correlations between artifacts using …

Design Of A 350 Kw Silicon Carbide Based 3-Phase Inverter With Ultra-Low Parasitic Inductance, Matthew Feurtado

Graduate Theses and Dissertations

The objective of this thesis is to present a design for a low parasitic inductance, high power density 3-phase inverter using silicon-carbide power modules for traction application in the electric vehicles with a power rating of 350 kW. With the market share of electric vehicles continuing to grow, there is a great opportunity for wide bandgap semiconductors such as silicon carbide (SiC) to improve the efficiency and size of the motor drives in these applications. In order to accomplish this goal, careful design and selection of each component in the system for optimum performance from an electrical, mechanical, and thermal …

Culturally Responsive Pedagogy And Writing Achievement For Native High School Students, Angelia Christine Greiner

Graduate Theses and Dissertations

This study focuses on the effects of culturally responsive pedagogy as it is implemented in a high school classroom with Native American students. This mixed methods case study collects, analyzes and synthesizes both quantitative and qualitative data within an overall formative and experimental design approach to measure the effects of culturally responsive pedagogy on students’ writing and their attitudes about writing. The study identified specific approaches to literacy instruction that hold promise for engaging Native students. Furthermore, findings from the study reveal the use of visual art as a particularly powerful tool that extends students’ meaning-making skills, leading to more …

Exploring Sediment Compaction In Experimental Deltas: Towards A Meso-Scale Understanding Of Coastal Subsidence Patterns, Samuel Mason Zapp

Graduate Theses and Dissertations

Subsidence in low elevation coastal areas has been extensively researched through direct field measurement, numerical modelling, and stratigraphic reconstruction of ancient sediment deposits. Here I present the first investigation of subsidence due to sediment compaction and consolidation in two laboratory scale river delta experiments. Compactional subsidence rates have never been thoroughly quantified in the experimental setting, though this mechanism is found to be a primary creator of total relative sea level rise which will likely cause coastlines to retreat in the coming years. Spatial and temporal trends in subsidence rates in the experimental setting may elucidate behavior which cannot be …

Examining The Effects Of Reducing The Cement Content Of Portland Cement Concrete Pavement, Bryan Casillas

Graduate Theses and Dissertations

Portland cement is a significant component in a concrete mixture. For concrete used in portland cement concrete pavement (PCCP), the Arkansas Department of Transportation (ARDOT) specifies a minimum cementitious material content of 564 lb/yd3 and a maximum water-cementitious material ratio of 0.45. Prior research conducted at the University of Arkansas, TRC 0603, indicated concrete mixtures used in five bridge decks throughout Arkansas achieved the required 28-day strength at seven days, and the measured compressive strength at 28 days was 30% greater than required. The use of high strength concrete in pavements throughout the state can increase cracking and consequently reduce …

Quantifying Workability, Compactability, And Cohesion Gain Of Asphalt Emulsion Cold In-Place Recycling, Sadie Casillas

Graduate Theses and Dissertations

To maximize the life and quality of a pavement, proper maintenance and rehabilitation are essential. Strategies for pavement rehabilitation with many sustainable benefits are pavement recycling. This dissertation focuses on two types of in-situ pavement recycling: Cold in-place recycling (CIR) stabilized with asphalt emulsion and full depth reclamation (FDR) stabilized with asphalt emulsion or foamed asphalt. One white paper (Chapter 2), two accepted peer reviewed journal articles (Chapters 3 and 4), and one submitted peer reviewed journal article (Chapter 5) are presented in this document to create better understanding of the unique material characterization of asphalt emulsion cold recycled materials, …

Verifying The Calcium Oxychloride Threshold In Cementitious Pastes, Fatoumata Traore

Graduate Theses and Dissertations

Calcium oxychloride (CAOXY) formation is a serious deterioration mechanism known to cause joint damage in concrete pavements. CAOXY is the product of a chemical reaction between calcium chloride (CaCl2) or magnesium chloride (MgCl) deicing salts and calcium hydroxide in the cementitious matrix. Currently, the accepted CAOXY threshold at which deterioration is mitigated in cementitious paste is 15 g/100 g paste (15 oz/100 oz paste); however, this limit was developed using flexural strength testing. For this investigation, the current threshold was evaluated using compressive strength and mass change over time in paste specimens exposed to CaCl2. Fly ash is used to …

Commodity-Based Freight Activity On Inland Waterways Through The Fusion Of Public Datasets For Multimodal Transportation Planning, Magdalena I. Asborno

Graduate Theses and Dissertations

Within the U.S., the 18.6 billion tons of goods currently moved along the multimodal transportation system are expected to grow 51% by 2045. Most of those goods are transported by roadways. However, several benefits can be realized by shippers and consumers by shifting freight to more efficient modes, such as inland waterways, or adopting a multimodal scheme. To support such freight growth sustainably and efficiently, federal legislation calls for the development of plans, methods, and tools to identify and prioritize future multimodal transportation infrastructure needs. However, given the historical mode-specific approach to freight data collection, analysis, and modeling, challenges remain …

Dissecting The Cellular Control Of Septin Organization In A Global Cereal Killer, Nawaraj Dulal

Graduate Theses and Dissertations

Rice blast disease, caused by the filamentous fungus Magnaporthe oryzae, destroys sufficient rice each year to feed 60 million people, and is a serious threat to global food security. A wheat-adapted lineage of M. oryzae now poses threat to global wheat production. Rice blast disease is currently controlled using limited fungicides, and the emergence of fungicide resistance within M. oryzae populations is a growing concern. There is a pressing need to identify new classes of fungicides to control the disease, which requires better understanding of the basic biology of the pathogen. To establish disease, M. oryzae forms a specialized dome …

Introducing An Indigenous Non-Toxigenic Aspergillus Flavus Strain Isolated From Iraqi Corn Grains As A Bio-Control Agent To Reduce Aflatoxin Contamination In Corn Grains, Ali Almatakeez

Graduate Theses and Dissertations

Mycotoxin contamination of cereal crops, such as maize and sorghum, is a global concern because of the potential health effects on humans and animals. Although substantial research has been conducting regarding mycotoxin prevention and mitigation, little information is available about the association of mycotoxin-producing fungi with corn and sorghum grain in Iraq. Identifying and refining indigenous atoxigenic strains to reduce mycotoxin contamination of maize and sorghum has the potential to enhance the nutritional value of these grains while reducing economic losses. However, to our knowledge, this tactic has not yet been adopted by agricultural authorities and farmers in Iraq. To …

Genetic Architecture Of Salt And Drought Tolerance In Cowpea, Waltram Second Ravelombola

Graduate Theses and Dissertations

Cowpea [Vigna unguiculata (L.) Walp.] is a diploid and nutrient-dense legume species. It provides affordable source of protein to human. Cowpea cultivation is prevalent in Africa, Asia, the western and southern U.S., and Central and South America. However, earlier reports have shown that drought and salt stress can be devastating to cowpea production. The objectives of this study were to screen for salt and drought tolerance in cowpea and to identify molecular markers associated with these traits. Simple methodologies to screen for drought (Chapter 2) and salt tolerance were developed (Chapter 3). Results suggested that: 1) a total of 14, …

Drivers Of Rural Development Strategies At The Farm Level: A Case Study On Circular Agriculture In The Netherlands, Anna Berger Mulder

Graduate Theses and Dissertations

The sustainability of the agricultural sector worldwide is increasingly being pressurized by ecological, economic, and social developments. The Dutch government is promoting enhancing circular agriculture as an important rural development strategy in response to the challenges the sector is facing. All farmers in the country will have to be involved in closed cycles by 2030, but many farmers do not want to or cannot make this transition. This study aims to identify the different factors that influence a farmer’s decision to transition towards circular agriculture. Based on thirteen semi-structured interviews with already transitioned farmers, a policy officer, a consultant, and …

Models For Data Analysis In Accelerated Reliability Growth, Cesar Alexander Ruiz Torres

Graduate Theses and Dissertations

This work develops new methodologies for analyzing accelerated testing data in the context of a reliability growth program for a complex multi-component system. Each component has multiple failure modes and the growth program consists of multiple test-fix stages with corrective actions applied at the end of each stage. The first group of methods considers time-to-failure data and test covariates for predicting the final reliability of the system. The time-to-failure of each failure mode is assumed to follow a Weibull distribution with rate parameter proportional to an acceleration factor. Acceleration factors are specific to each failure mode and test covariates. We …

Machine Tool Communication (Mtcomm) Method And Its Applications In A Cyber-Physical Manufacturing Cloud, S M Nahian Al Sunny

Graduate Theses and Dissertations

The integration of cyber-physical systems and cloud manufacturing has the potential to revolutionize existing manufacturing systems by enabling better accessibility, agility, and efficiency. To achieve this, it is necessary to establish a communication method of manufacturing services over the Internet to access and manage physical machines from cloud applications. Most of the existing industrial automation protocols utilize Ethernet based Local Area Network (LAN) and are not designed specifically for Internet enabled data transmission. Recently MTConnect has been gaining popularity as a standard for monitoring status of machine tools through RESTful web services and an XML based messaging structure, but it …

Sensitivity Of Enlisttm And Roundup Ready Xtend® Technologies To Auxin Herbicides And Comparison Of Resistance To Susceptible Cotton And Soybean Cultivars, James Rose

Graduate Theses and Dissertations

Increases in weed resistance have led to the development of new herbicide-resistant crop technologies, namely the Roundup Ready Xtend® and EnlistTM weed control systems. These new technologies provide resistance to applications of the synthetic auxins dicamba or 2,4-D, respectively, in traited cotton or soybean. It is unknown if there is any resistance to other herbicides within the synthetic auxin group (WSSA Group 4) in these traited crops. Experiments were conducted with auxin herbicides representing all five families within WSSA Group 4. Herbicides were applied either preemergence (PRE) or postemergence (POST) relative to the crop in a single application. Applications were …

Outcomes Of Platform Openness In Complementary Markets, Franck Loic Soh Noume

Graduate Theses and Dissertations

Mobile platform ecosystems are hyper-competitive environments. They provide important entrepreneurial opportunities for businesses that develop mobile apps. Platform openness is foundational in mobile platform ecosystems as it enables interactions between complements and platform. Although there are several studies on the impact of platform openness, our understanding of the outcomes of platform openness remains limited. In this dissertation, we examine thoroughly underexplored facets of platform openness as well as understudied outcomes. In the first essay, we investigate the impact of platform openness on incumbent complements’ performance outcomes. We unravel important causal mechanisms related to competition dynamics between new entrants and incumbent …

Remote Sensing And Gis Study Of Hazards And Risks In East Africa, Hafid Nanis

Graduate Theses and Dissertations

East Africa encompasses numerous developing countries and involves one of the most active continental rifts on Earth; namely, the East African Rift System. This region is prone to diverse geohazards due to its geographical location at the plate boundary. Several damaging events had happened across the region and more are predicted to occur in the near future. Therefore, it is crucial to investigate, assess, and forecast natural hazards and potential risks in the region. In this dissertation, remote sensing and Geographic Information System (GIS) were employed to conduct three independent studies focused on assessing geohazards in east Africa. Each study …

Design Of Control System With Feedback Loop For A Pulsatile Pump, Ian Scott Sanders

Graduate Theses and Dissertations

This paper describes the design and implementation of a closed-loop proportional, integral, differential (PID) control system for a custom in-house pulsatile pump apparatus for the University of Arkansas Biomedical Department. The control system is designed to control a MOONS’ PL34HD0L8500 hybrid stepper motor using a dual H-bridge motor driver network with four pulse-width modulated (PWM) inputs to drive a pulsatile pump apparatus at motor stepping frequencies up to 2kHz. The speed of the motor is controlled from a pressure profile transmitted from an external source over RS-232 communication that specifies the motor speed, number of datapoints, and an array of …

Election Day — Documentary, John Thomas Tarpley

Graduate Theses and Dissertations

Election Day is a three-channel documentary chronicling the places, personalities, and tone of Little Rock, Arkansas, during its titular midterm Election Day in November 2018. Throughout the course of the day, the film branches across the city, capturing mini-narratives, bits of conversation, and tableau of civic activity in the public sphere. It is less concerned with the quantitative facts of the day as it is with conveying the transitory social expressions and moods of a modern, southern city on a uniquely American day. This project represents my continued documentary interest in creating inclusive, contemporary local portraits and counter-historical chronicles of …

Development Of A Reference Design For A Cyber-Physical System, Nicholas Paul Blair

Graduate Theses and Dissertations

The purpose of this thesis is to develop a reference design to assist in the selection of security practices in power electronics design. A prototype will be developed from this reference design for evaluation. This evaluation will include a brief cost/benefit analysis to gauge the efficacy of implementing each layer of security throughout the power electronics design process. This thesis will also describe the obstacles and effectiveness of integrating a Trusted Platform Module (TPM) into a cyber-hardened grid-connected device. The TPM device is a secured crypto processor that assists in generating, storing, and restricting the use of cryptographic keys. The …

New Flesh Cinema: Japanese Cyberpunk-Body Horror And Cinema As Catharsis In The Age Of Technology, Sarah Henry

Graduate Theses and Dissertations

This thesis provides a critical analysis of a specific group of films that combine the subgenres of cyberpunk and body horror which I call New Flesh Cinema. Films of this subgenre counter fears and anxieties of technological advancements by re-imagining the rise of technology and its societal effects as a transitional process through the illustration of literal and visceral depictions of the necessary alterations people will have to undergo in order to transition successfully into the new world. To contradict apocalyptic fears of advancing technology, these films offer a vision of a “New Flesh.” I argue the films share three …

Study On New Sampling Plans And Optimal Integration With Proactive Maintenance In Production Systems, Sinan Obaidat

Graduate Theses and Dissertations

Sampling plans are statistical process control (SPC) tools used mainly in production processes. They are employed to control processes by monitoring the quality of produced products and alerting for necessary adjustments or maintenance. Sampling is used when an undesirable change (shift) in a process is unobservable and needs time to discover. Basically, the shift occurs when an assignable cause affects the process. Wrong setups, defective raw materials, degraded components are examples of assignable causes. The assignable cause causes a variable (or attribute) quality characteristic to shift from the desired state to an undesired state.

The main concern of sampling is …

Investigation Of The Role Of Heparin-Binding Pocket In Amyloid Fibrils Formation Of Fgf-1, I Gusti Ayu Agung Septiari

Graduate Theses and Dissertations

Human acidic fibroblast growth factor (aFGF/hFGF-1) is one of the promising molecules to be investigated to generate an in-depth understanding of the pathological mechanism of Alzheimer's disease (AD) neurodegenerative disorder characterized by the presence of amyloid fibrils. Some in vivo and human brain tissue studies proved the correlation of high-level expression of FGF-1-induced neuroinflammation and the occurrence of AD. The presence of amyloid fibrils as a hallmark of AD can be related to the generic property of the proteins to form amyloid fibrils; High level of FGF-1, in this case, may contribute to the formation of amyloid fibrils. As a …