Digital Commons Network^™

Friction And Wear Of Polytetrafluoroethylene/Graphene Oxide Composite Thin Films, Justin Kyle Carter

Graduate Theses and Dissertations

Polytetrafluoroethylene (PTFE) is a commonly used solid lubricant due to its low coefficient of friction and chemical inertness. As a polymer, PTFE suffers from high wear and low adhesion to substrates limiting its use as a thin film. Thin PTFE films are ideal candidates for solid lubrication in micro-machines and bearing applications. The main goal of this work is to enhance the durability of thin PTFE films through the addition of few layered graphene oxide (GO) as filler. In order to address adhesion issues, the addition of an adhesive layer of polydopamine (PDA) between stainless steel substrates and thin PTFE …

Crack Growth Behavior Under Creep-Fatigue Conditions Using Compact And Double Edge Notch Tension-Compression Specimens, Santosh B. Narasimha Chary

Graduate Theses and Dissertations

The American Society for Testing and Materials (ASTM) has recently developed a new standard for creep-fatigue crack growth testing, E 2760-10, that supports testing compact specimens, C(T), under load controlled conditions. C(T) specimens are commonly used for fatigue and creep-fatigue crack growth testing under constant-load-amplitude conditions. The use of these specimens is limited to positive load ratios. They are also limited in the amount of crack growth data that can be developed at high stress intensity values due to accumulation of plastic and/or creep strains leading to ratcheting in the specimen. Testing under displacement control can potentially address these shortcomings …

Assessing Trichloromethane Formation And Control In Algal-Stimulated Waters Amended With Nitrogen And Phosphorus, Clinton Mash

Graduate Theses and Dissertations

Nitrogen (N) and phosphorus (P) enrichments can stimulate algal growth in drinking water sources, which can cause increased production of disinfection byproduct (DBP) precursors. However, the effect of systematic N and P enrichments on DBP formation and control has not been adequately studied. In this work, we enriched samples from a drinking water source - sampled on April 5, May 30, and August 19, 2013 - with N and P to stimulate algal growth at N:P ratios covering almost five orders of magnitude (0.2-4,429). To simulate DBP-precursor removal processes at drinking water treatment plants (DWTPs), the samples were treated with …

The Effects Of Salinity On Pythium Disease Of Rice And Soybean, Terea Jeanette Stetina

Graduate Theses and Dissertations

Increasing salinity is an important factor limiting agricultural productivity worldwide. In addition to direct effects on growth and yield, diseases also may be affected. This study characterized the effects of soil salinity on seedling disease of soybean and rice caused by Pythium spp. Controlled environment experiments on soybean used two cultivars which differed in chloride tolerance and soil treated with a CaCl₂ solution to create a range of electrical conductivity (EC) levels. For soybean, soil was either not infested or infested with Pythium sylvaticum or P. aphanidermatum (pathogenic to soybean), or P. oligandrum (not pathogenic to soybean). Twenty-one days …

Assessing The Impact Of Chlorine Residual On Trihalomethane And Haloacetonitrile Formation Under Chlorination And Chloramination Disinfection Regimes, Thien Duc Do

Graduate Theses and Dissertations

A disinfection byproduct (DBP) formation potential (FP) test can be used to indirectly measure the concentration of DBP precursors in natural waters, permitting assessment of various DBP-related treatment processes and control strategies. While these tests require a 7-day chlorine residual (CR) between 3-5 mg L^-1 as Cl², it is not well known if this recommended residual corresponds to the true DBPFP (i.e., the maximum concentrations) for trihalomethanes (THMs) and haloacetonitriles (HANs). In this study, THMs and HANs were quantified as a function of CR under three common disinfection regimes: (1) free chlorine at pH 7.0 (FC7), (2) …

Effects Of Rain And Simulated Rain On Deoxynivalenol Levels In Grain And Chaff Of Winter Wheat With Fusarium Head Blight, Manoj Kumar Pun

Graduate Theses and Dissertations

Wheat grain affected by Fusarium head blight (FHB) contains the mycotoxin deoxynivalenol (DON) that is harmful to humans and animals. Reducing the amount of DON in grain is the goal of management practices for FHB so it is important to understand the factors affecting DON in grain. Some studies on the effects of late-season moisture found increases in DON while others found decreases due to leaching. The objectives of this study were to determine effects of late-season rain and misting on DON concentration in wheat spike tissues and to quantify the amount of DON leached from spikes. Field experiments were …

I Am Bedu: The Changing Bedouin In A Changing World, Nancy Allison Browning

Graduate Theses and Dissertations

Change occurs throughout the world on a daily basis, and as a result, its inhabitants are encouraged to change as well. The population learns to adapt in various ways in order to survive, often times causing traditional practices to be forced aside in order to make way for more modern methods. Today, the Bedouin lifestyle is no longer limited to the classification of a pastoral nomad, located in the desert living in goat-hair tents, and herding camels. While there are several factors that could be taken into consideration in order to unpack what it means to be a Bedouin in …

The Birth Of A Playwright Through The Evolution Of The One-Act Play Stripped, Bear; The Film Stripped, Bear; And The Full-Length Play American Bear, Larry Michael Mitchell

Graduate Theses and Dissertations

The Birth of a Playwright through the Evolution of the One-act Play Stripped, Bear; the film Stripped, Bear; and the Full-Length Play American Bear follows the inception, birth, and evolution of a ten-minute, one-act, film, and full-length play: three major iterations of the same source material. Through this exploration, the reader will not only see how the work was changed through outside forces such as form and function but internal struggles within a young playwright as he struggles to find a final form for his first major work while attempting to establish himself as a playwright both within the field …

Competing Risks Models Of Farm Service Agency Guaranteed Operating And Farm Ownership Loans, Deng Long

Graduate Theses and Dissertations

This thesis examines the possible outcomes (expired with no loss, settled for loss, still performing) of loans and the time to hazard events of over 19,000 guaranteed operating and farm ownership loans which were provided by the Farm Service Agency (FSA). Loans guaranteed by FSA are made by commercial banks, Farm Credit System (FCS), or other lenders to farmers who have limited ability to obtain loans from normal sources without the Federal guarantee. The guarantee allows for payment up to 95 percent when borrowers default. Cox proportional hazards models for operating loans and farm ownership loans are estimated to identify …

An Experimental And Computational Evaluation Of The Importance Of Molecular Diffusion In Gas Gravity Currents, Jeremy Jac Herman

Graduate Theses and Dissertations

The accidental release of hazardous, denser-than-air gases during their transport or manufacture is a vital area of study for process safety researchers. This project examines the importance of molecular diffusion on the developing concentration field of a gas gravity current released into a calm environment. Questions which arose from the unexpectedly severe explosion in 2005 at Buncefield, England were of particular interest. The accidental overfilling of a large tank with gasoline on a completely calm morning led to a massive open air explosion. Forensic evidence showed that at the time of ignition, a vapor cloud, most of which now appears …

Tin Sensitization For Electroless Plating, Xingfei Wei

Graduate Theses and Dissertations

The tin sensitization process has been used in electroless plating since 1940s Brenner and Riddell developed the electroless plating for surface metallization method. It was found to be an interesting topic to study tin sensitization for chemically controlling metal deposition on different substrates, because the tin sensitization process had critical effects on the electroless plated metal thin films. Nowadays electroless plating metal deposition is still an important method for depositing metals. It has a few advantages over the vapor deposition and electrodeposition method, such as work in an ambient condition, on nonconductive substrates, and without extra power input. Applying electroless …

The Effects Of Social Contextual Factors On Rater Motivation And Performance Ratings, Emilija Djurdjevic

Graduate Theses and Dissertations

Performance appraisal research (e.g., Longenecker, Sims, & Gioia, 1987; Wang, Wong, & Kwong, 2010) suggests that inaccuracies in performance ratings are largely a result of intentional rating distortion, or rater motivation. Researchers have noted that raters sometimes have multiple and conflicting goals when providing performance ratings (e.g., Murphy, Cleveland, Kinney, Skattebo, Newman, & Sin, 2003). According to rater goal theory (e.g., Cleveland & Murphy, 1992), rater goals are influenced by the performance appraisal context, mediating the relationship between the context of performance appraisal and performance ratings. Studies suggest that the context affects performance ratings, but conceptualizations of the performance appraisal …

Risky Business? An Analysis Of Teacher Characteristics And Compensation Preferences, Daniel Henry Bowen

Graduate Theses and Dissertations

Teacher quality has a significant impact on both student learning gains and later life outcomes. With this is mind, policymakers implement reforms to attract and retain more effective educators. A major obstacle for designing these policies is that the ingredients for training, as well as initially identifying, effective teachers remain largely a mystery. However, there are strong theoretical arguments for certain education policy reforms producing improvements in the quality of the teacher workforce. One increasingly popular example is performance-based pay. Performance pay has the potential to better align teachers' incentives to produce increases in student achievement. Paying teachers based on …

Developing A Presumptive Test For Select Synthetic Cannabinoids, Carrie Snyder

Graduate Theses and Dissertations

Synthetic cannabinoids (SC's) began to gain popularity around the world in 2009. Since then, many of the compounds have been outlawed and methods developed to detect them and their metabolites using mass spectrometry. Our work investigated the possibility of developing a colorimetric presumptive test. The SC JWH-019 was synthesized and its ketone targeted as a possible reaction site. Many SC's contain ketones and thus a reaction at this site would be applicable to many of the compounds. Since JWH-019 is costly and time consuming to synthesize, much of the experimental work was done using benzophenone (BP). BP contains a diaryl …

Evaluating Economic Impacts Of Switchgrass Harvest Time, Nathanial Elsworth Cahill

Graduate Theses and Dissertations

This thesis deals with cost of production for cellulosic energy crops of switchgrass, miscanthus, and energy sorghum. The first chapter explains the rationale for development of decision support software called Energy Crop Analysis & Planning (ENCAP) and Switchgrass Harvest Date, Yield, Nutrient Removal Estimator (SHYNE). The second chapter examines harvest date implications on yield, nutrient removal, opportunity cost of modified sale dates, and post-harvest storage losses. This harvest date analysis leads to a profit maximizing harvest date from the perspective of the producer. While this harvest date may be optimal for the producer, biorefineries may be interested in sourcing switchgrass …

The Mechanisms Of Interpersonal Privacy In Social Networking Websites: A Study Of Subconscious Processes, Social Network Analysis, And Fear Of Social Exclusion, Bryan I. Hammer

Graduate Theses and Dissertations

With increasing usage of Social networking sites like Facebook there is a need to study privacy. Previous research has placed more emphasis on outcome-oriented contexts, such as e-commerce sites. In process-oriented contexts, like Facebook, privacy has become a source of conflict for users. The majority of architectural privacy (e.g. privacy policies, website mechanisms) enables the relationship between a user and business, focusing on the institutional privacy concern and trust; however, architectural privacy mechanisms that enables relationships between and among users is lacking. This leaves users the responsibility to manage privacy for their interpersonal relationships. This research focuses on the following …

The Impact Of Cognitive Behavior Techniques On The Vocational Identity Of Persons With Disabilities Receiving Ssi/Ssdi Benefits, James Joseph Quinn

Graduate Theses and Dissertations

This study examines the effects of Cognitive Behavior Therapy (CBT) on the vocational identity, self-efficacy, and vocational satisfaction of persons with disabilities receiving SSI/SSDI. This study was carefully planned to help persons with disabilities obtain employment. A review of the relevant literature was used to determine the need for the study and to support the study. Forty participants, all were enrolled into a vocational rehabilitation program were selected for the study. Threats to internal and external validity were taken into consideration and controlled for. They received CBT as a treatment intervention to change their beliefs and irrational thoughts about the …

Development Of Novel Subunit Vaccine Against H5n1 Influenza, Lu Zhang

Graduate Theses and Dissertations

Influenza is a common infectious disease resulting from a frequently mutated RNA virus. Vaccination is currently the most effective method to prevent people from seasonal or pandemic influenza. The production of traditional egg-based influenza vaccine is time-consuming and provides limited effect against new strains. Therefore, it is necessary to develop a rapid method to produce influenza vaccines. We proposed a novel influenza vaccine based on the E.coli expression system. Hemagglutinin (HA) is the major target surface protein of influenza virus for vaccine development. In this study, we sub-cloned the HAs encoding gene into an E. coli expression vector; the signal …

Sexual Pleasure And Enhancement: Implications For College Sexuality Education, Jessica Maureen Harris

Graduate Theses and Dissertations

The purpose of this study was to determine what sexual activities and behaviors college students are participating in, including the use of sexual enhancement products during both partnered and solo sexual activities. Pleasure and sexual satisfaction remain largely absent from today's sexuality education curricula, resulting in most young adults not being aware of the importance of "sexual pleasure, including autoeroticism, as a source of physical, psychological, intellectual and spiritual well-being" (WAS, 1994).This study looked at college students and their the use of sexual enhancement products during partnered and solo sexual activities, in order to provide a set of baseline measures …

Successful Marketing Strategies For Promoting Event Destinations, Evease Iniece Tucker

Graduate Theses and Dissertations

Travel and tourism has been recognized as being an important driver of jobs, growth and economic recovery in the United States. Meetings, events and incentive travel contribute $98.7 billion of the direct spending, $15.0 billion in taxes and 859,000 jobs. As a result, destination marketing organizations (DMOs) in the United States are taking advantage of this impact for growth in their destinations. As a destination marketing organization's main job responsibility is to promote their destination to attract visitors, which requires superior marketing strategies to achieve these goals.

This research investigates the marketing strategies of DMOs in the United States. The …

An Open Source, Line Rate Datagram Protocol Facilitating Message Resiliency Over An Imperfect Channel, Christina Marie Smith

Graduate Theses and Dissertations

Remote Direct Memory Access (RDMA) is the transfer of data into buffers between two compute nodes that does not require the involvement of a CPU or Operating System (OS). The idea is borrowed from Direct Memory Access (DMA) which allows memory within a compute node to be transferred without transiting through the CPU. RDMA is termed a zero-copy protocol as it eliminates the need to copy data between buffers within the protocol stack. Because of this and other features, RDMA promotes reliable, high throughput and low latency transfer for packet-switched networking. While the benefits of RMDA are well known and …

Sedimentary Provenance Of The Wedington Member, Fayetteville Shale, From Age Relations Of Detrital Zircons, William Tyson Cains

Graduate Theses and Dissertations

U-Pb geochronology of detrital zircons collected from the Chesterian Wedington Sandstone allows interpretation of sediment provenance and dispersal patterns in the southern midcontinent during the Late Mississippian. Detrital zircons analyzed from six samples of Wedington Sandstone yielded a final result of 565 concordant analyses used for interpretation. Results are plotted as Probability-Density Plots to interpret the spectrum of ages. Significant peaks occurred at 350-500 Ma, 950-1250 Ma, 1300-1500 Ma, 1600-1800 Ma, 1800-2300 Ma, and >2500 Ma. These peaks are interpreted as sourced by crystalline rocks within the Laurentian craton from Taconic-Acadian, Grenville, Midcontinent Granite-Rhyolite, Yavapai-Mazatzal, Paleoproterozoic, and Superior Provinces. The …

Consumer Adoption Of Health Information Systems, Sankara Subramanian Srinivasan

Graduate Theses and Dissertations

At nearly 18 percent of the country's GDP, the U.S. healthcare industry continues to wrestle with growing cost and a quality of care that does not match the increased spending. The dominant focus to date has been on promoting Health IT (HIT) system implementation and digitizing health records at the provider's end, with scant attention to the role of the patient in the healthcare process. The source of inefficiency in the healthcare system is not only on account of shortcomings at the provider's end but also due to non-compliance (such as failing to adhere to medication advice and follow-up visits) …

In Vitro Analysis Of Short Chain Fatty Acids And Human Fecal Microbiota Stimulated By Pectin Sources, Byungjick Min

Graduate Theses and Dissertations

As interest increases for colonic health, various studies have been conducted to investigate functional ingredients for host health and prevention of chronic disease in humans such as colon cancer and Type 2 diabetes. In particular dietary fiber has been reported to have beneficial effects on colonic health. More recently, dietary fiber has been categorized based on its characteristics and numerous studies have been conducted to determine correlations with chronic diseases. Pectin is a naturally occurring biopolymer that has been used in various applications for purposes of pharmaceutical and biotechnology. Pectin is a soluble dietary fiber and can be entirely fermented …

Molecular And Biochemical Mechanisms Of Pathogenesis In The Maize Foliar Pathogen Cercospora Zeae-Maydis, Winfred-Peck Dorleku

Graduate Theses and Dissertations

GLS is a serious foliar disease of maize, a major staple crop grown commercially in the USA for both human and animal feed production, and increasingly, for ethanol production. The disease is caused by two Cercospora species, C. zeae-maydis and C. zeina, both of which infect maize in the USA and in other parts of the world, with yield losses potentially greater than 50%, depending on local conditions. In culture, C. zeae-maydis produces a phytotoxic, host non-specific perylenequinone, cercosporin, and abscisic acid (ABA), for which there is no known pathological or physiological function in the fungus. Experimental evidence indicates …

A Bandwidth-Conserving Architecture For Crawling Virtual Worlds, Dipesh Gautam

Graduate Theses and Dissertations

A virtual world is a computer-based simulated environment intended for its users to inhabit via avatars. Content in virtual worlds such as Second Life or OpenSimulator is increasingly presented using three-dimensional (3D) dynamic presentation technologies that challenge traditional search technologies. As 3D environments become both more prevalent and more fragmented, the need for a data crawler and distributed search service will continue to grow. By increasing the visibility of content across virtual world servers in order to better collect and integrate the 3D data we can also improve the crawling and searching efficiency and accuracy by avoiding crawling unchanged regions …

Preservice Candidates' Rating Of Effectiveness In Agricultural Education Through Structured Communication With Cooperating Teachers, Christopher Lee Hunt

Graduate Theses and Dissertations

The relationship between cooperating teacher and student has been found as one of the key elements that affect the overall teaching efficacy of student teachers and their decision to enter the teaching field after graduation (Edgar, 2007; Edgar, Roberts, & Murphy, 2011,2008; Kasperbauer et al., 2007a; Roberts, Greiman, Murphy, Ricketts, Harlin, & Briers 2009; Roberts, Harlin, & Briers, 2007, Roberts, Harlin, & Ricketts, 2006; Roberts Mowen, Edgar, Harlin & Briers, 2007, Stripling, Ricketts, Roberts & Harlin, 2008; Wolf, 2011; Wolf et al., 2010). Therefore, determining impacts towards teaching efficacy during the student teaching experience could play a vital role in …

A Reconfigurable Digital-To-Analog Converter With Supply Invariant Linearity, Nicholas J. Chiolino

Graduate Theses and Dissertations

A novel reconfigurable digital-to-analog converter (DAC) with supply independent linearity is presented. The process agnostic converter achieves wide supply range operation and re-configurability by being charge based. This converter consists of a 7-bit parallel digital input control core and an analog "summing" core utilizing charging capacitors with an operational transconductance amplifier in a voltage-follower configuration. This topology is highly configurable to allow for optimization across process voltages, step sizes and low power operation. The specification of the DAC is (1) supply independence (2) low power operation (3) operation up to 200 kHz and (4) conversion control through a DAC enable …

Effect Of Functional Starch In Brown Rice And Grain Sorghum On Plasma Glucose And Insulin Responses In Humans, Nicole Marie Poquette

Graduate Theses and Dissertations

Diabetes and obesity are chronic illnesses increasing at dramatic rates in the U.S. and around the world. Research has looked to prevent or control diabetes and obesity through functional ingredients such as healthy-dietary carbohydrates to control blood glucose levels. Starch is a principle carbohydrate, which influences blood glucose levels, and measuring starch digestibility fractions can help predict the glucose response in the body. The objectives of this study were to investigate the functional starch content of parboiled brown rice flour and grain sorghum flour, and measure the effects on postprandial plasma glucose and insulin levels of 14 and 10 healthy …

Long-Term Residue And Water Management Effects On Soil Respiration And Soil Aggregate Stability In A Wheat-Soybean, Double-Crop System In Eastern Arkansas, Sharon Faye Smith

Graduate Theses and Dissertations

Sustainability in agriculture is paramount to assuring continued production from our most naturally fertile soils. Storing carbon (C) in soil as organic matter through sustainable agricultural management practices can both remove atmospheric C and improve soil quality. The objective of this study was to evaluate the long-term effects of water management (irrigation and dryland), residue management [burn and no-burn, conventional (CT) and no-tillage (NT)] and residue/fertility level (high and low) on soil respiration and aggregate stability in a wheat- (Triticum aestivum L.) soybean [Glycine max (L.) Merr.], double-crop system in a silt-loam soil (Aquic Fraglossudalf) in the Mississippi River Delta …