Digital Commons Network^™

New Titanate Bioceramic Nanomaterials For Drug Delivery And Controlled Release, Seaab Imad Sahib

Graduate Theses and Dissertations

Nanomaterials have attracted much attention for biomedical applications due to their unique characteristics that are proven to be potential in cell sensing, drug delivery, biological membrane penetration, biocompatibility, and tissue adhesion. The outcomes of this dissertation presented in chapter III-V mainly discuss new approaches in drug delivery, cellular uptake improvement, and neuronal regeneration and protection using a well-optimized titanium-based nanomaterial. In particular, Chapter III summarizes the impact of two different versions of the titanate nanowires on ameliorating the delivery of the antimicrobial and anticancer drug in vitro. Those drugs were loaded on the surface of the fabricated nanowires and characterized …

Evaluation Of Nitrous Oxide Emissions From Furrow-Irrigated Rice On A Silt-Loam Soil In Arkansas, Jordan M. Slayden

Graduate Theses and Dissertations

As the number one rice (Oryza sativa)-producing state in the United States, Arkansas also ranks fourth as the largest user of groundwater. Recently, due to the development of drought- resistant hybrid cultivars, the furrow-irrigated rice production system has become an increasingly popular alternative to traditional flood-irrigated production with respect to conserving groundwater and maintaining yield. However, other environmental parameters, like greenhouse gas emissions, specifically nitrous oxide (N2O), have yet to be evaluated under furrow-irrigated rice. The objectives of this study were to i) evaluate the effects of site position (i.e., up-, mid-, and down-slope) and tillage treatment [i.e., conventional tillage …

Development Of Aptamer Rolling Circle Amplification Platform As A Vaccine Adjuvant To Control Salmonella In Broiler Chickens, Abigeal Iyabode Omolewu

Graduate Theses and Dissertations

Salmonella has been a major source of concern in public health and food industry. It is the cause of gastrointestinal illness and fever called salmonellosis. Severe cases of salmonellosis have resulted in hospitalization and even death around the world. Salmonella can be found in the intestinal tract of animals including chickens and can be transmitted to human through contaminated food. Hence, it is highly important to find ways of reducing the transmission of Salmonella from chickens to humans. This work is focused on the control of Salmonella in broiler chicken through the development of novel vaccine adjuvant. Two different aptamer …

The Role Of Sex: An Analysis Of U.S. Attitudes Toward Climate Change, Chloe Riggs

Graduate Theses and Dissertations

This study analyzes the intersection of sex, environmental risk perception of climate change, and feminism. More specifically, with a sample size of 8,280 respondents from the American National Election Studies (ANES) 2020 Times Series Study, this research examines the relationship between pro-environmental attitudes and sympathy for feminism, controlling for sex, as well as if a measure of sympathy for feminism influences pro-environmental attitudes, controlling for demographic (age, education, race, sex, and income) and political preference (political ideology and party affiliation) variables. Previous literature strongly supports a sex gap in risk perception, a pattern known as the White Male Effect (WME) …

A Double-Sided Stack Low-Inductance Wire-Bondless Sic Power Module With A Ceramic Interposer, Si Huang

Graduate Theses and Dissertations

The objective of this dissertation research is to develop a novel three-dimensional (3-D) wire bondless power module package for silicon carbide (SiC) power devices to achieve a low parasitic inductance and an improved thermal performance. A half-bridge module consisting of 900-V SiC MOSFETs is realized to minimize stray parasitic inductance as well as to provide both vertical and horizontal cooling paths to maximize heat dissipation. The proposed 3-D power module package was designed, simulated, fabricated and tested. In this module, low temperature co-fired ceramic (LTCC) substrate with vias is utilized as an interposer of which both top and bottom sides …

Designing Digital Antiquity: Classical Archaeology In New Virtual Applications, William Loder

Graduate Theses and Dissertations

In this thesis, I argue that the combination of existing archaeological theory with game design theory offers an innovative avenue for creating serious 3D applications of archaeological sites in virtual reality that can be productively used for pedagogical, research, and outreach solutions. In this thesis, I engage with the archaeological theories of phenomenology and sensory studies, briefly touching on structure and agency as well as discussion of some current digital applications in use in the field. For this project, I am interested in game design theory as it relates to education and I view Virtual Reality as an important tool …

Statistical Modeling, Learning And Computing For Stochastic Dynamics Of Complex Systems, Mohammadmahdi Hajiha

Graduate Theses and Dissertations

With the recent advances in sensor technology, it is much easier to collect and store streams of system operational and environmental (SOE) data. These data can be used as input to model the underlying behavior of complex engineered systems and phenomenons if appropriate algorithms with well-defined assumptions are developed. This dissertation is comprised of the research work to show the applicability of SOE data when fed into proposed tailored algorithms. The first purposes of these algorithms are to estimate and analyze the reliability of a system as elaborated in Chapter 2. This chapter provides the derivation of closed-form expressions that …

Examining The Relationship Between Library Services Use And Fall-To-Fall Retention In Community College Libraries, Eric Deatherage

Graduate Theses and Dissertations

Community college libraries exist to support institutional outcomes. One such outcome is student retention. This study’s purpose was to fill the gap in the literature at the community college level, proposing that a model including all library service use types would explain variance in student retention beyond that explained by total library financial expenditure. Services included were numbers of physical materials circulated, digital books circulated, e-serials used, reference transactions, library presentations, attendees at presentations, gate counts, and interlibrary loan materials borrowed. Additionally, it was proposed that the relationship between gate counts of physical entry into the library and student retention …

Economic Potash Fertilizer Rate Recommendations, Kimberly B. Oliver

Graduate Theses and Dissertations

This thesis is comprised of two studies that estimate profit-maximizing potassium (K) fertilizer application rates for various crops across different time periods. Estimation of profit-maximizing fertilizer-K rate (K*) for both studies considered the initial soil test level of K (STK) and yield response information, as traditional recommendations do, and added crop price and the cost of fertilizer. Profit maximum occurs where the marginal revenue from additional yield is equal to the marginal cost of applying an additional unit of fertilizer-K. The first study calculated K* for corn (Zea mays) and cotton (Gossypium hirsutum) and compared results to previous studies on …

Effects Of Localized Oxygen Production By Electrolysis On The First-Generation Glucose Sensor Response, Nandita Halder

Graduate Theses and Dissertations

Glucose sensors are very important for detecting blood glucose both in vitro and in vivo. First-generation glucose biosensors were based on the glucose oxidase (GOx) enzyme using molecular oxygen as the electron acceptor and therefore oxygen dependent. Unfortunately for in-vivo work, oxygen in the body is variable and limited. Alternative approaches to overcome the oxygen dependency came with their own limitations. The widely used and commercially available ex-vivo glucose test strip uses a mediator in place of oxygen to free it from oxygen dependency. The mediator-based technology, in most cases cannot be transferred to in vivo applications due to the …

The Passion Of Ken Williams: The Double Life Of A Mayor, The Newspaper That Brought Him Down, And The Story Of Journalism In America, Michael Adkison

Graduate Theses and Dissertations

In November 2007, a team of reporters from the Benton County Daily Record published an expose revealing that Ken Williams, the mayor of Centerton, Arkansas, had been living a double life. In his former life as Don LaRose, he was a preacher in the Northeast, who one day vanished without a trace. His wild saga includes Satanists, truth serums, and a supposed murder. The Benton County Daily Record confronted the former reverend several times before he finally confessed to his double life. The next morning, he resigned as mayor, saying that the decisions he made were for the protection of …

Greenhouse Tomatoes: Process Simulation, Juan Gabriel Marin Jr.

Graduate Theses and Dissertations

Growing population demand and challenges brought on by climate change have spurred the need for more resilient fruit and vegetable supply chains. One agricultural technology of significant interest is the use of greenhouses for food production. Greenhouses create a stable and adaptable environment for crops such as tomatoes to grow year-round. Fresh tomatoes are the second most consumed vegetable per capita in U.S. diets, currently averaging 20.7 pounds. The growing consumption of fresh tomatoes has been the result of increasing cultural diversity in the United States.

To meet the growing demand, Venlo-type greenhouses have been frequently used by growers. It …

Use Patterns And Influencing Factors Of Irrigation Best Management Practices In The Lower Mississippi River Basin, Merri E. Day

Graduate Theses and Dissertations

This study uses the 2016 Irrigation Survey from Arkansas, Louisiana, and Mississippi to document the use of irrigation best management practices (IBMPs), analyze use patterns, and use quantitative methods to determine factors that influence producers’ decisions regarding IBMPs. IBMPs included in the survey can be grouped as: field management practices (zero-grade leveling, precision-grade leveling, end blocking, warped surface, and deep tillage), water flow control practices (computerized pipe-hole selection, multiple-inlet irrigation, surge irrigation, alternate wetting and drying, cutback irrigation, flow meters, and pump timers), water recovery/storage practices (tail-water recovery system and on-farm storage reservoir), and advanced irrigation scheduling practices (soil moisture …

Substance Use And Psychological Distress Correlates Of Sleep Quality Among College Students, Juanybeth Morales Ortega

Graduate Theses and Dissertations

Poor sleep quality in college students is a major problem associated with adverse health outcomes, cognitive performance, substance use, and psychological distress. Our study explored how substance use and psychological distress are associated with the sleep quality of college students. We analyzed secondary data collected in 2019 using a cross-sectional survey design. Measures included participants’ demographic characteristics, sleep quality using the Pittsburg Sleep Quality Index (PSQI), drug use, depression using the Patient Health Questionnaire-9 (PHQ-9), and suicidality. After excluding participants with missing information for sleep quality, a total of 555 students remained for the analysis. Our bivariate analysis found that …

Integrated Weed Management Strategies For Palmer Amaranth (Amaranthus Palmeri) In Cotton And Soybean Production Systems, Rodger Bruce Farr

Graduate Theses and Dissertations

Management of Palmer amaranth [Amaranthus palmeri (S.) Wats.] in the Midsouth in soybean [Glycine max (L.)] and cotton (Gossypium hirsutum L.) production systems has become increasingly troublesome due to resistance to many of the commonly utilized herbicides in these systems. Developments have been made to utilize new chemistries as well as incorporate integrated weed management strategies to control Palmer amaranth, but questions have risen given the economic feasibility or effectiveness of these new strategies. Additionally, regulation has limited producers’ abilities to utilize some herbicide chemistries. As a result, experiments were conducted to 1) understand the utility of isoxaflutole in isoxaflutole-tolerant …

The Electrification Of The Kitchen: On The Energy Consumption Of Common Electric Cooking Appliances, Hozen Ricchie Rose Asok Rose

Graduate Theses and Dissertations

In developed countries, electricity has been gaining popularity as a source of energy for meal preparation. Utilizing electricity produced from renewable resources along with efficient electrical cooking appliances could result in sustainable clean cooking. The first objective of this research was to study the efficiency of common electrical cooking appliances—namely induction, resistance plate, resistance coil, infrared, and electric pot— by the water boiling test and the simmering test. The induction and electric pot were observed as the most efficient devices for the water boiling test. For simmering, which mimics many cooking processes, the electric pot and resistance coil were the …

News Media Trust And Mistrust During The Covid-19 Pandemic, Kaitlyn Seiter

Graduate Theses and Dissertations

With the uncertainty and growing information surrounding the COVID-19 pandemic, news media consumption has increased drastically compared to pre-pandemic consumption. At the start of the pandemic, 94% of Americans reported closely following COVID-19 news, with more than half of Americans spending more than two hours consuming COVID-19 news everyday (SSRS, 2020). With the news media serving as a critical source of information through this public health crisis, the public’s reactions, behaviors, and attitudes to the pandemic stem from the level of trust they have in the news media to share COVID-19 information. Because of this, this study examines trust in …

Thermometry Via Diffusion In Ferrous Core-Shell Nanoparticles For Induction Heating Applications, Hayden Carlton

Graduate Theses and Dissertations

Induction heating causes the release of enormous amounts of heat from dispersed magnetic nanoparticles. While the rate of heat transfer can be easily quantified calorimetrically, measuring the temperature of the nanoparticles on the nanoscale presents experimental challenges. Fully characterizing the temperature and thermal output of these magnetic particles is necessary to gauge overall heating efficiency and to provide a more holistic understanding of heat transfer on the nanoscale. Herein, this dissertation seeks to develop a novel nanoparticle thermometry technique, which correlates diffusion behavior in core-shell nanoparticles to local temperature. Initial measurements suggested that heating silica capped ferrous nanoparticles (SCNPs) via …

Recalibrating Student Services: Examining Staff Perceptions Of Services During Covid-19, Justin White

Graduate Theses and Dissertations

As a result of the 2019 global coronavirus pandemic, nearly every business and industry in the United States was forced to adapt its operations to accommodate the restrictions that a community health crisis necessitated. This study examined the experiences of front-line Enrollment Services staff while serving students during the pandemic at one community college in the Midwestern United States. The study focused on staff perceptions of how college policies, processes, and leadership affected the student onboarding experience that encompasses the complete path a student takes from beginning as an applicant to becoming an enrolled student in the classroom. The study …

Component Damage Source Identification For Critical Infrastructure Systems, Nathan Davis

Graduate Theses and Dissertations

Cyber-Physical Systems (CPS) are becoming increasingly prevalent for both Critical Infrastructure and the Industry 4.0 initiative. Bad values within components of the software portion of CPS, or the computer systems, have the potential to cause major damage if left unchecked, and so detection and locating of where these occur is vital. We further define features of these computer systems and create a use-based system topology. We then introduce a function to monitor system integrity and the presence of bad values as well as an algorithm to locate them. We then show an improved version, taking advantage of several system properties …

Theoretical Investigations Of The Structural, Dynamical, Electronic, Magnetic, And Thermoelectric Properties Of Corhysi (Y = Cr, Mn) Quaternary Heusler Alloys, Abdullah Hussain Hzzazi

Graduate Theses and Dissertations

Thermoelectric materials have potential properties for utilizing waste heat. The computations are used to estimate the electronic structure of CoRhYSi (Y = Cr, Mn) Quaternary Heusler alloys, as well as their elastic and magnetic characteristics. The full-potential linearized augmented plane wave is used in the calculations. The exchange-correlations are addressed using Perdew–Burke and Ernzerhof's generalized gradient approximation (GGA-PBE). With the exception of CoRhCrSi and CoRhMnSi, which are simple ferromagnets that are approximately half metallic in nature, electronic structure calculations demonstrate that these compounds have a gap in the minority states band and are obviously half-metallic ferromagnets. The magnetic moments of …

A Focused Evaluation Of Sales Employees' Ethics Training And Its Effect On The Diffusion Of Ethics In A Financial Organization, Justin Luebker

Graduate Theses and Dissertations

Ethical scandals have continued to batter corporate America into the twenty-first century. Companies such as Enron and MCI WorldCom became household names overnight because of ethical issues that shuttered the organizations’ operations and stunned shareholders. Training has served as a primary mechanism for companies to impart ethical values in employees and leadership teams. However, despite the ongoing focus and resources dedicated to education and associate development in this area, historically there appears to be no diffusion of ethical standards within organizations. There is a lack of consensus in current research regarding the effectiveness of organizational ethics training and its ability …

Improve The Prediction Of Camber, Deflection, And Prestress Losses In Precast, Prestressed Concrete Bridge Girders, Ahmed Ali Hussein Al Mohammedi

Graduate Theses and Dissertations

Many precast, prestressed concrete girders have camber less or higher than the design values. This discrepancy between the design and the actual camber creates construction problems when installing the cast-in-place concrete deck. The objective of this research was to improve the accuracy of estimating long-term camber, deflection, and prestress losses of precast, prestressed concrete girders.

The experimental program consisted of measuring concrete properties and performing field measurements of camber, deflection, and prestress losses for girders in Arkansas. The investigation involved testing nine full-scale girders from two prestressed concrete plants that regularly supply concrete girders to bridge projects in Arkansas. The …

Comparing Organic And Conventional Yield Responses To Climate Variations, Joost Wilken Meyer

Graduate Theses and Dissertations

This thesis compares the responses of organic yields and conventional yields towards climate variations. To achieve this objective, weather variables such as growing season weather conditions (average temperature, precipitation, cloud cover, relative humidity, drought index), weather anomalies, the occurrence of severe or extreme droughts and excessive rainfalls, are combined with 23 data sets gathered from previous studies that compare organic and conventional yields from the same location and time periods. To narrow the scope, the thesis focuses on soybean, maize, and wheat production in Europe and North America. Study-level fixed-effects models are used to control for any time-invariant factors such …

Data Analytics For Sustainable Food And Agriculture Systems, Megan Lord Reavis

Graduate Theses and Dissertations

The increasing concentration of anthropogenic greenhouse gases in the atmosphere is altering the climate, posing a serious threat to global agriculture and food security. Agriculture and food production contribute a quarter of all GHG emissions produced, so there is a critical need to limit emissions in this area while increasing food production to feed the anticipated 10 billion people by 2050. To address the needs of the future, data-driven solutions are needed to guide decision-making and provide support for actionable climate mitigation and survival strategies. Research efforts must be focused on analyzing problems on multiple scales, identifying new ways to …

Sigesn Light-Emitting Devices: From Optical To Electrical Injection, Yiyin Zhou

Graduate Theses and Dissertations

Si photonics is a fast-developing technology that impacts many applications such as data centers, 5G, Lidar, and biological/chemical sensing. One of the merits of Si photonics is to integrate electronic and photonic components on a single chip to form a complex functional system that features compact, low-cost, high-performance, and reliability. Among all building blocks, the monolithic integration of lasers on Si encountered substantial challenges. Si and Ge, conventional epitaxial material on Si, are incompetent for light emission due to the indirect bandgap. The current solution compromises the hybrid integration of III-V lasers, which requires growing on separate smaller size substrates …

Multifunctional Programmable Self-Assembled Nanoparticles In Nanomedicine, Yoshie Sakamaki

Graduate Theses and Dissertations

Developing methodologies to control the architecture of nanoparticles (NPs) at the atomic level prevents their inhomogeneity and leads to a variety of expected functions. Rationally designed nanoparticles can either be programmed or crystallized structures into pre-determined structures achieving tunable particle pore size and physiochemistry. In this dissertation, two broad classes of multifunctional nanoparticles are developed, metal-organic frameworks and DNA-NP aggregates.

Metal-organic frameworks are a novel class of highly porous crystalline materials built from organic linkers and metal cluster-based secondary building units. However, applications in bioremediation have not been developed very well especially in applications regarding drug delivery systems (DDS). The …

Investigation Of Optical And Structural Properties Of Gesn Heterostructures, Oluwatobi Gabriel Olorunsola

Graduate Theses and Dissertations

Silicon (Si)-based optoelectronics have gained traction due to its primed versatility at developing light-based technologies. Si, however, features indirect bandgap characteristics and suffers relegated optical properties compared to its III-V counterparts. III-Vs have also been hybridized to Si platforms but the resulting technologies are expensive and incompatible with standard complementary-metal-oxide-semiconductor processes. Germanium (Ge), on the other hand, have been engineered to behave like direct bandgap material through tensile strain interventions but are well short of attaining extensive wavelength coverage. To create a competitive material that evades these challenges, transitional amounts of Sn can be incorporated into Ge matrix to form …

Palmer Amaranth [Amaranthus Palmeri (S.) Wats.] Resistance To S-Metolachlor In The Mid-Southern Us And S-Metolachlor Dissipation In Soil, Koffi Badou Jeremie Kouame

Graduate Theses and Dissertations

Palmer amaranth [Amaranthus palmeri (S.) Wats.] presents both a high genetic diversity and propensity to evolve resistance to herbicides of several sites-of-action which have made it one of the worst weeds in US agriculture. In Arkansas, Palmer amaranth is resistant to herbicides of seven sites-of-action, which are 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibitor, acetolactate synthase inhibitors, microtubule inhibitors, protoporphyrinogen oxidase inhibitors, very long chain fatty acid inhibitors, glutamine synthetase inhibitors, and hydroxyphenylpyruvate dioxygenase inhibitors. Sustainable management requires a better understanding of its biology and that of herbicide environmental fate. This research had five objectives: 1) characterize the current status of Palmer amaranth …

Faculty Perception Of Inclusive Instruction At Three South-Central Community Colleges, Karen R. O'Donohoe

Graduate Theses and Dissertations

Enrollment rates for student with disabilities in higher education continue to rise, particularly in 2-year colleges, but graduation rates have not kept pace due to barriers not addressed by traditional disability supports (Black et al., 2014; NCES, 2019; Smedema et al., 2015). Inclusive instruction is a low-cost, high-impact solution that can be implemented on any campus (Black et al., 2014; Lombardi et al., 2013; Roberts et al., 2011). This quantitative study utilized a cross-sectional descriptive non-experimental research design that explored faculty self-reported attitudes and actions associated with inclusive instruction at three of the largest degree-granting, two-year institutions in a single …