Digital Commons Network^™

Application Of Microwave-Assisted Technology For Single-Pass Drying Of Rough Rice, Rebecca Mawusi Bruce

Graduate Theses and Dissertations

The 915 MHz industrial microwave is a novel technology that has the potential to achieve one-pass drying of rice within a short drying duration and reduce rice drying losses. However, processing recommendations for the commercialization of this technology for rice drying is lacking. The goal of this research is to provide processing conditions that are useful for the commercialization of the 915 MHz industrial microwave technology for rice drying. This was achieved by studying the impact of microwave specific energy and processing conditions such as harvest moisture content, milling duration, and aging on the physicochemical properties of a 915 MHz …

Allelopathic Effect Of Cereal Straw Extracts On Growth Of Raphidocelis Subcapitata And Microcystis Aeruginosa, Holly Wren

Graduate Theses and Dissertations

Harmful algal blooms are increasing in size, duration, and intensity around the globe. For several decades, cereal straws have been recognized as a viable algal control method, though the mechanisms by which cereal straws inhibit algae remain a topic of research. The objectives of this study were to evaluate the effectiveness of decomposing cereal straw extract, particularly rice (Oryza sativa) and barley (Hordeum vulgare) straw extract, to inhibit the green alga Raphidocelis subcapitata or cyanobacteria Microcystis aeruginosa in bioassays and to determine if the effectiveness of decomposing rice straw extract is altered by the presence of natural organic matter or …

The Effects Of Side-Channel Attacks On Post-Quantum Cryptography: Influencing Frodokem Key Generation Using The Rowhammer Exploit, Michael Jacob Fahr

Graduate Theses and Dissertations

Modern cryptographic algorithms such as AES and RSA are effectively used for securing data transmission. However, advancements in quantum computing pose a threat to modern cryptography algorithms due to the potential of solving hard mathematical problems faster than conventional computers. Thus, to prepare for quantum computing, NIST has started a competition to standardize quantum-resistant public-key cryptography algorithms. These algorithms are evaluated for strong theoretical security and run-time performance. NIST is in the third round of the competition, and the focus has shifted to analyzing the vulnerabilities to side-channel attacks. One algorithm that has gained notice is the Round 3 alternate …

Catalytic Activity Of Tungsten-Dioxo And Tungsten-Diimido Complexes, Kayla Denike

Graduate Theses and Dissertations

Due to the significant decline in the availability of petrochemical resources and the increasing demand for the useful olefin mixtures extracted from oil, a sustainable and efficient alternative to these materials has become vital. Fortunately, renewable biomass derived materials may serve as a sustainable solution to the limited resources problem. Molecules derived from the degradation of biomasses are highly oxygenated and highly functionalized. Developing processes to efficiently defunctionalize these oxygen-rich materials will lead to potential up-conversion to carbon chemicals. Homogeneous catalytic deoxygenation processes present an opportunity to access valuable carbon commodity chemicals from biomass derived polyols. This dissertation details the …

Technology Agency On Usage: Grounded Theory And Measurement Of Technology Induced Usage Behavior, Sandip Kumar Sarkar

Graduate Theses and Dissertations

Most of today’s software applications involve a dyadic interplay between human and technology agency. The use of algorithms driven by user can alter users' interaction patterns by affording them novel and relevant technology action possibilities. I argue that algorithmic activities and features embedded in apps can keep users on IT applications (apps) for longer periods of time. I refer to the behavior of interacting with the apps for longer time than planned as technology-induced excessive use. While practitioners are beginning to recognize characteristics of technology-induced excessive use, research on this topic is very limited. I used a multimethod approach to …

The Effect Of Water Management And Ratoon Rice Cropping On Methane Emissions And Harvest Yield In Arkansas, Marguerita Leavitt

Graduate Theses and Dissertations

Sustainable intensification of rice farming is crucial to meeting human food needs while reducing environmental impacts. Rice produces 8% of all anthropogenic CH4, which is a potent greenhouse gas. CH4 emissions can potentially be reduced by cultivation practices that minimize the number of days the fields are saturated, such as dry-seeding instead of water-seeding and irrigation using the alternate wetting and drying (AWD) technique instead of delayed, continuous flooding (DF). Ratoon cropping, wherein a second crop of rice is grown from the harvested stubble of the first crop, can be used to produce additional yield with minimal labor, but may …

Quantum Dots In Two-Dimensional Tungsten Diselenide, Jeb Allen Michael Stacy

Graduate Theses and Dissertations

This work focuses on the investigation of single and double quantum dots in two-dimensional transition metal dichalcogenide tungsten diselenide (WSe_2) as a means to evaluate the valley degree of freedom as a potential qubit and ambipolar tungsten diselenide monolayers as single photon sources. Gate-defined quantum dots in monolayer and bilayer WSe_2 were fabricated and characterized. Single dot devices are gated from above and below the WSe_2 to accumulate a hole gas. Temperature dependence of Coulomb-blockade peak height is consistent with single-level transport. Excited-state transport in the quantum dot is shown for both monolayer and bilayer devices. Magnetic field dependence of …

Effective Knowledge Graph Aggregation For Malware-Related Cybersecurity Text, Phillip Ryan Boudreau

Graduate Theses and Dissertations

With the rate at which malware spreads in the modern age, it is extremely important that cyber security analysts are able to extract relevant information pertaining to new and active threats in a timely and effective manner. Having to manually read through articles and blog posts on the internet is time consuming and usually involves sifting through much repeated information. Knowledge graphs, a structured representation of relationship information, are an effective way to visually condense information presented in large amounts of unstructured text for human readers. Thusly, they are useful for sifting through the abundance of cyber security information that …

Controller Platform Design And Demonstration For An Electric Aircraft Propulsion Driv, Rosten Sweeting

Graduate Theses and Dissertations

With the growth in the aerospace industry there has been a trend to optimize the performance of an aircraft by reducing fuel consumption and operational cost. Recent advancements in the field of power electronics have pushed towards the concepts of hybrid electric aircraft also known as more electrical aircrafts. In this work, a custom controller board for an electric aircraft propulsion drive was designed to drive a permanent magnet synchronous motor. Design of the controller board required knowledge of the topology selection and power module selections. Simulations of the system were performed using MATLAB/Simulink to analyze the overall performance of …

Xps And Ipe Determination Of Band Offsets Of Germanium Based Materials, Justin Michael Rudie

Graduate Theses and Dissertations

Germanium tin and silicon germanium tin are group IV semiconductor alloys that have gained significant interest in recent years for their potential use in optoelectrical devices. While silicon and germanium are indirect bandgap materials on their own, alloying them with tin in sufficient quantities leads to a transition to direct bandgap alloys. Direct gap performance opens the door for efficient light emitting and detecting devices fabricated entirely on group IV materials that are compatible with the industry standard CMOS manufacturing techniques. Germanium tin and silicon germanium tin have bandgaps that respond to light in the mid to near infrared spectrum …

Study Of Thin Gan/Ingan/Gan Double Graded Structures For Future Photovoltaic Application, Mirsaeid Sarollahi

Graduate Theses and Dissertations

Indium gallium nitride (In_x Ga_(1-x) N) materials have displayed great potential for photovoltaic and optoelectronic devices due to their optical and electrical properties. Properties such as direct bandgap, strong bandgap absorption, thermal stability and high radiation resistance qualify them as great materials for photovoltaic devices. The tunable bandgap which absorbs the whole solar spectrum is the most significant feature which became attractive for scientists. The bandgap for these materials varies from 0.7 eV for InN to 3.4 eV for GaN covering from infrared to ultraviolet. In_x Ga_(1-x) N wurtzite crystal is grown on GaN buffer layer by Molecular Beam Epitaxy …

Closing The Gender Gap In Entrepreneurship Education, Carolyn J. Rodeffer

Graduate Theses and Dissertations

Entrepreneurship education in higher education has been cited as a key strategy in filling the entrepreneurship talent pool, preparing students with the skills and confidence needed to start new ventures (Westhead & Solesvik, 2016). However, outcomes of entrepreneurship education for female students are less positive than for their male counterparts (Shinnar et al., 2012; Westhead & Solesvik, 2016; Wilson et al., 2007). Working within the frameworks of Bandura’s self-efficacy theory (1977), Azjen’s theory of planned behavior (1991), and Steele and Aronson’s stereotype threat theory (1995), this quantitative study utilized an experimental research design to assess the impact of role model …

Wind Tunnel Modeling Of Jack Rabbit Ii Mock Urban Environment Gas Concentration Measurements, Sami S. Fares

Graduate Theses and Dissertations

The 2015 Jack Rabbit (JR) II field trials were conducted to improve understanding of the denser-than-air dispersion of chlorine in an urban environment. The field study involved five large-scale, outdoor release trials of chlorine in a mock urban environment (MUE) at Dugway Proving Ground (DPG). Various instrumentation was deployed, including JazTM Ultraviolet-Visible (UV-Vis) point sensors capable of measuring gas-phase chlorine concentration throughout the mock urban array.

The Chemical Hazards Research Center (CHRC) was tasked by the Chemical Security Analysis Center (CSAC) with the Mock Urban Wind Tunnel (MUWT) program to study the 2015 JR II Trials at wind tunnel scale. …

Beyond Nutrition: Three Essays On The Effects Of Food Processing And Sustainability Labeling On Consumer Perceptions And Evaluations, Garrett J. Rybak

Graduate Theses and Dissertations

Recent consumer trends reveal increasing demand for greater product transparency including how products are processed, the types of ingredients used, and the impact on the environment. As a result, food marketers often use a combination of processing, nutrient content, and/or sustainability claims to convey specific information to consumers. Considering these developments, several questions arise about how these claims affect consumer evaluations of healthfulness, sustainability, disease risk, and intent to purchase while considering the unregulated and regulated nature of many of these claims.

In Essay One, we extend our understanding of consumer responses to package claims by comparing the direct and …

Port Infrastructure Resilience Through Combined Wind-Surge Demand Characterization, Kaley Callaway

Graduate Theses and Dissertations

The United States economy is reliant on maritime transportation for 70% of imports and exports. Structures that are integral to the operation of ports, such as cranes, are jeopardized when tropical storms approach land. While wind is the only environmental load used to design dockside container cranes, storm surge often accompanies severe wind events and can create large structural loads. This study focuses on determining coupled storm-surge demands and the effect of waves on dockside container cranes. A damage index prediction tool that considers both maximum wind speed and storm surge height is developed and applied to historical hurricane data …

Rodent Dental Microwear Texture Analysis As A Proxy For Fine-Scale Paleoenvironment Reconstruction, Jenny H. E. Burgman

Graduate Theses and Dissertations

Dental microwear texture analysis (DMTA) of fossil fauna has become a valuable tool for dietary inference and paleoenvironment reconstruction. Most of this work has utilized larger taxa with larger home ranges. These studies may result in broader-scale habitat inferences that could mask the details of complex mosaic habitats. Rodent DMTA offers an opportunity to work at finer spatial scales because most species have smaller home ranges. Rodents are also keystone species within their ecosystems, abundant, ubiquitous, and found in many fossil deposits. These attributes make them excellent proxies for environmental reconstructions. However, the application of DMTA to rodents remains relatively …

Refining Particle Size Specification For Asphalt Emulsion, Pedro Luis Diaz Romero

Graduate Theses and Dissertations

Pavements begin to deteriorate as soon as they are constructed, and traffic is released. The rate at which a pavement deteriorates depends on the material quality, the environment, and the loads carried. To properly preserve pavements and extend their life, various pavement preservation treatments are used. For flexible pavements, a considerable number of these treatments use asphalt emulsion (which are refer to simply emulsions from here on). Emulsions are classified based on their particle charge and reactivity. Emulsions used in chip seals are usually of rapid set reactivity and are classified based on tests over fifty years old.

It has …

Cyclic Behavior Of Laterally Skewed Special Moment Frame Connections: Experimental Testing And System-Level Analyses, Mohammad Hossein Kashefizadeh

Graduate Theses and Dissertations

Special moment frames (SMFs) are frequently used in high seismic areas for architecturally constrained designs. SMFs provide lateral system stiffness without the use of braces that often obstruct views and architectural features. Current American Institute of Steel Construction (ASIC) provisions (AISC 341-16) provide prequalified SMF connection details; however, all prequalified details only consider orthogonal connections between the beam and column. This dissertation investigates the effect of adding skew within SMF beam-to-column connections. The study presented herein involves system-level dynamic time-history analyses of skewed SMF connections, the analytical component-level investigation into the effect of the concrete slab on behavior of the …

Understanding Thermal Comfort Impact And Air Movement Around Open Stairs Through The Use Of Cfd Modeling, Ethan Davidson

Graduate Theses and Dissertations

The air exchange between two floors of a building has an impact on thermal comfort. The present research attempts to quantify this impact and identify the contributing factors disrupting the thermal comfort on and around stairs. Various heating and cooling scenarios were analyzed, using CFD modeling, in a simple two-story building separated by a single staircase. The research examines a single building layout with a fixed inlet and outlet configuration. In addition, the study investigated the short-term impact on thermal comfort. As a result, the duration of the simulations varies from two and half minutes to ten minutes, consistent with …

A Boy Born On Wednesday, Charles Krampah

Graduate Theses and Dissertations

My relocation to America has presented an unprecedented space for self-examination. The components of my identity and personality have been laid bare before me; My blackness in the face of racism and white hegemony, my African heritage in the face of post-colonialism and imperialism, and my faith in the face of an increasingly secular western culture.

Am I who thought I was? Am I more or less? Why do I feel like a different person, and what does this mean for my future?

My research and art practice serve as a form of introspection. I tell an internal story in …

Rapid Non-Nuclear In Situ Density And Moisture Content Measurement Of Soil, Mateo Lopez

Graduate Theses and Dissertations

Adequate soil compaction is important for the stability and safety of structures and transportation infrastructure. Thus, methods utilized to obtain properties that control the quality of compaction in the field are essential to ensure proper construction. These properties include; total density, dry density, total unit weight and dry unit weight of the compacted soil. The most common method to measure these properties in the field is the Nuclear Density Gauge. Moisture content and density results are obtained using the Nuclear Density Gauge in one to four minutes. However, this method requires specialized training and strict storage requirements in addition to …

Validation Of Cfd Tornado Pressure On Building And Wind Field With Ttu Vortex Chamber Measurements, Sumit Verma

Graduate Theses and Dissertations

Structural failure of low-rise buildings is the root cause of higher number of casualties, death tolls and economic losses at the place of occurrence of tornadoes. Proper design of low-rise buildings in tornado-prone areas require accurate estimation of tornado-induced wind loads; however, exhaustive research to estimate the wind loads reliably on buildings during tornadic events is still lacking. Several studies have been carried out to investigate the magnitude of forces induced by tornado winds on buildings from experimental as well as computational side. However, the wind pressures obtained on the building from different experimental studies have shown significant variation from …

Development Of An Accelerated Life Testing Method For Reliability Assessment Of Wire Bonded Interconnects Subjected To Mechanical And Electromigratory Stresses, Whit Vinson

Graduate Theses and Dissertations

Power electronic advancement trends indicate that device power density will continue to increase as a result of increased power requirements and desired device form factor reduction in order to reduce weight and material costs and increase ease of integration into next-generation power systems. With these advancements come concerns regarding device reliability. The compounded effects of increased power density and form factor reduction in electrical conductors will yield amplified joule heating effects in addition to the already increasing device temperature profiles resulting from the incorporation of wide bandgap technology into power systems. Joule heating effects can lead to a variety of …

Concurrent Load And Construal On Planning, Maximilian Fey

Graduate Theses and Dissertations

Planning for the future is a necessary activity which spans across all aspects of an individual’s life. Concurrent cognitive load has been shown to hinder future planning, whereas concrete construal of events has been shown to increase planning efficacy. Interestingly, a limited literature speaks towards cognitive load inducing concrete construal. However, the two constructs predict differing outcomes on future planning therefore the interaction of cognitive load inducing a concrete construal is particularly interesting. The research study tested whether differing levels of concurrent cognitive load increase or decrease planning efficacy. The intention of the research was to elucidate whether cognitive load …

Studying Acetylation Of Aconitase Isozymes By Genetic Code Expansion, Jessica Araujo

Graduate Theses and Dissertations

The tricarboxylic acid (TCA) cycle is a very important, centrally located, energy-producing pathway that connects numerous other metabolic and regulatory pathways. Enzymes of this cycle have been more recently implicated in various cancers and neurometabolic disorders, however, the exact mechanism by which this happens becomes quite complex when considering the potential modification of these enzymes and the presence of multiple forms of the enzymes and therefore there is much to be studied in this area.

Aconitase has become a recent enzyme of interest as its substrate, citrate, has been found to play a major role in many vital processes within …

Improving Gifted And Talented Education In Arkansas: Identification, Academic Benefits, And Local Norms, Bich Thi Ngoc Tran

Graduate Theses and Dissertations

In the United States, education policies differ from state to state. Local research, therefore, is important to inform educators, policymakers, and researchers on the ground. This dissertation leverages ten years of administrative data to study three questions about gifted and talented (G/T) identification and education in Arkansas: does the current system identify the right students? Are gifted and talented programs beneficial for students? And, how can we improve diversity in gifted and talented education? Leveraging logistic regression, mixed-effects models, and descriptive statistics, I sought to provide answers to these three questions. First, are academically ready students from low-income families being …

Teaching Programmable Microcontrollers To Novice Users In A College Of Agriculture: Effects On Attitude, Self-Efficacy, And Knowledge, Grant T. Hood

Graduate Theses and Dissertations

This thesis consists of two articles that examined an instructional treatment based on the use of Arduino UNO R3 programmable microcontrollers in a fundamentals of agriculture systems technology course at the University of Arkansas. The first article examined students’ breadboarding and programming self-efficacy and knowledge of Arduino. The treatment consisted of a three-class-period instructional treatment, starting with a pretest before instruction to measure students’ baseline interest, knowledge, and self-efficacy of breadboarding and programming Arduino. This was followed with a short 30-minute instructional video explaining basic Arduino programming and breadboarding. Next a hands-on laboratory activity requiring students to breadboard and program …

Supervised Representation Learning For Improving Prediction Performance In Medical Decision Support Applications, Phawis Thammasorn

Graduate Theses and Dissertations

Machine learning approaches for prediction play an integral role in modern-day decision supports system. An integral part of the process is extracting interest variables or features to describe the input data. Then, the variables are utilized for training machine-learning algorithms to map from the variables to the target output. After the training, the model is validated with either validation or testing data before making predictions with a new dataset. Despite the straightforward workflow, the process relies heavily on good feature representation of data. Engineering suitable representation eases the subsequent actions and copes with many practical issues that potentially prevent the …

Predicting The Likelihood And Scale Of Wildfires In California Using Meteorological And Vegetation Data, Matthew Walters

Graduate Theses and Dissertations

Wildfires have devastating ecological, environmental, economical, and public health impacts through the deterioration of water and air quality, CO2 emissions, property damage, and lung illnesses. The early detection and prevention of wildfires allow for the minimization of these risks. The use of Artificial Intelligence (AI) in wildfire detection and prediction has been highly researched as a tool to assist firefighters in stopping wildfires in its early stages. The three common wildfire prediction categories include image and video detection, behavior prediction, and susceptibility prediction. Data such as climate, weather, vegetation, satellite images, and historical wildfire data is most commonly used. Many …

Upward Cross-Class Interactions At Work: An Investigation Of Emotional And Behavioral Outcomes, Emily Sue Corwin

Graduate Theses and Dissertations

Cross-class interactions—when an individual from a lower (higher) social class background interacts with an individual from a higher (lower) social class background (Truong et al., 2021)—are ubiquitous in the workplace and serve as a vehicle for the reproduction of inequality (Gray & Kish-Gephart, 2013). Substantial research has demonstrated that social class background matters, as individuals from working-class backgrounds face challenges in the job search process and may be less likely to be hired (DeOrtentiis et al., 2021; Fang & Saks, 2020), earn less money (Fang & Tilcsik, 2022), and are less likely to emerge as leaders compared to those from …