Digital Commons Network^™

Reliability-Based Design And Acceptance Protocol For Driven Piles, Joseph Jabo

Graduate Theses and Dissertations

The current use of the Arkansas Standard Specifications for Highway Construction Manuals (2003, 2014) for driven pile foundations faces various limitations which result in designs of questionable reliability. These specifications are based on the Allowable Stress Design method (ASD), cover a wide range of uncertainties, do not take into account pile and soil types, and were developed for general use. To overcome these challenges it is deemed necessary to develop a new design and acceptance protocol for driven piles. This new protocol incorporates locally calibrated RLFD resistance factors for accounting for local design and construction experiences and practices, as well …

Utilizing Failure Information For Mission Assessment And Optimization For Complex Systems, Charlie Destefano

Graduate Theses and Dissertations

This paper presents a new failure analysis method, Failure Identification for Mission Analysis (FIMA), which performs a general failure analysis for the overall state of a system, as well as a mission-specific analysis that identifies how failures may have differing effects on the various mission tasks that a system must complete. The FIMA method is capable of being implemented at any point in the design process. During early design stages, the FIMA method will identify various qualitative failure scenarios based on programmed functional relationships and any number of initial failures wished to be simulated. The functional relationships for this method …

Calibration Of Resistance Factors For Driven Piles Using Static And Dynamic Tests, Deshinka A. Bostwick

Graduate Theses and Dissertations

The field of geotechnical engineering has evolved from Allowable Stress Design (ASD) to Load Factor and Resistance Design (LRFD) which has led to a need to quantify the measures of uncertainty and the level of reliability associated with a project. The measures of uncertainty are quantified by load and resistance factors, while the level of reliability is driven by the amount of risk an owner is willing to take and is quantified by the reliability index. The load factors are defined through structural design codes, but the resistance factors have uncertainties that can be mitigated through reliability based design. The …

Identification Of Root-Knot Nematodes (Meloidogyne Spp.) Of Arkansas Using Molecular Diagnostics, Churamani Khanal

Graduate Theses and Dissertations

Root-knot nematodes (Meloidogyne spp.) are highly-adaptable, obligate plant parasites distributed worldwide. In addition, root-knot nematodes are an economically important genus of plant-parasitic nematodes. Meloidogyne incognita, M. arenaria, M. javanica, M. hapla and M. graminis have been reported from Arkansas during 1964 to 1994. Previous identifications were based primarily on morphological characters and host differentials. In this study, identification using molecular diagnostics methods was performed to identify Meloidogyne species present in Arkansas. A total of 106 soil and root samples from 36 of the 75 counties were collected and processed to obtain root-knot nematodes. Polymerase chain reaction (PCR) was performed …

Microbial Community Shifts Caused By Changes In The Primary Oxidant At A Drinking Water Treatment Plant, Connie Marie Moloney

Graduate Theses and Dissertations

Microbial communities resistant to common oxidants can cause concerns for water treatment plants (WTPs). If a bacterium is not fully oxidized during disinfection, these species can impede upon filtration processes or seed biofilms in the distribution system. In an effort to minimize disinfection by-products (DBP's) that result from the reaction of chlorine (Cl2) with natural organic matter, water treatment plants have the option to change their primary oxidant to chlorine dioxide (ClO2). The following study examines the change in microbial communities during the sedimentation process under differing oxidation regimes, specifically chlorine (Cl2) and ClO2 at the local water treatment plant …

Evaluation Of Medicago Truncatula Accessions For Triterpene Saponins And Their Potential Impacts On Plant Pests, Samantha Roberson

Graduate Theses and Dissertations

Plants have developed numerous ways to protect themselves from microbes and insects, including producing secondary metabolites that negatively impact an invading pathogen or pest. Saponins are specialized metabolites found in many plant species and may play a role in protecting the plant. Though saponins are found in many plant species, triterpene saponins are found primarily in dicotyledons, including legumes. Medicago truncatula is a model system for studying legume biology and some accessions accumulate high concentrations of saponins. Accessions of M. truncatula known to have differing levels of saponins in both foliar and root tissues were tested for their suitability as …

The Phenotypic Effects And Transcript Response Of Salt Stress, The Impact Of Viral Infection On Salt Stress Symptoms, And The Effect Of Salt Stress On Soybean Virus Vector Activity In Soybean Varieties That Vary In Chloride Uptake, Alma Glenn Laney

Graduate Theses and Dissertations

With the increase in saline soils worldwide, understanding the mechanisms for salt tolerance in plants is important to reduce yield loss due to salt stress. Soybean, Glycine max (L.) Merr., genotypes differ in chloride uptake with genotypes that take up chloride into foliar tissues tending to be salt-sensitive whereas those that partially exclude chloride from the leaves are more salt-tolerant. Transcriptional and physiological responses were measured in two soybean cultivars, Clark and Manokin, which differ in chloride uptake in response to salt stress and in combination with Soybean mosaic virus (SMV) and its aphid vector, Aphis glycines . The interaction …

Characterization Of A Novel Fungal-Specific Gene, Fug1, In Fusarium Verticillioides, John Byron Ridenour

Graduate Theses and Dissertations

Filamentous fungi are responsible for numerous plant and animal diseases. The filamentous ascomycete Fusarium verticillioides is a globally important pathogen of maize, capable of causing severe yield reductions and economic losses. Also of substantial concern is the contamination of infected kernels with fumonisins, toxic secondary metabolites linked to toxicoses in humans and livestock. The number of sequenced fungal genomes is rapidly increasing. However, functional characterization of fungal genes has not progressed at a comparable rate. In pathogenic fungi, uncharacterized genes represent a source for novel virulence factors or anti-fungal targets. Therefore, to fully understand the genetic mechanisms underlying fungal pathogenesis, …

Truckload Shipment Planning And Procurement, Neo Nguyen

Graduate Theses and Dissertations

This dissertation presents three issues encountered by a shipper in the context of truckload transportation. In all of the studies, we utilize optimization techniques to model and solve the problems. Each study is inspired from the real world and much of the data used in the experiments is real data or representative of real data.

The first topic is about the freight consolidation in truckload transportation. We integrate it with a purchase incentive program to increase truckload utilization and maximize profit. The second topic is about supporting decision making collaboration among departments of a manufacturer. It is a bi-objective optimization …

Essays On Moral Hazard, Bank Size, Influence, And Risk At The Federal Home Loan Banks, James Cash Acrey

Graduate Theses and Dissertations

Two chapters of research on the Federal Home Loan Bank advances, bank risk, and influence are presented. Federal Home Loan Bank (FHLB) advances are a growing source of debt financing for US banks. FHLB advances are not priced according to bank credit risk, creating potential for moral hazard. FHLB advances are positively related to contemporary bank risk, but the relation between prior advances and subsequent risk varies between large vs. small banks depending upon the risk measure used. The relation between FHLB advances and various measures of bank risk varies between pre-crisis (2005-07), crisis (2008-09), and post-crisis (2010-12) periods differently …

Consumer Acceptance And Willingness To Pay For Genetically Modified Rice In China: A Double Bounded Dichotomous Choic Contingent Valuation Survey Calibrated By Cheap Talk, Jing Jin

Graduate Theses and Dissertations

Considering population growth, limitations on land and water resources, and contamination to the ecosystem due to agricultural activities, current rice production in China is facing pressure to fulfill national demand. Self-sufficiency of rice has been a long-held political objective of the Chinese government and it is national goal to maintain the equilibrium between the national production and consumption or even achieve a supply surplus in rice. With the developing bio-technology of genetic modification (GM), scientists believe that using genetically modified cultivars may ease the pressure mentioned above. However, both the government and the people are very cautious about large-scale cultivation …

Designing Magnetically Responsive Ultrafiltration Membranes, Robert William Dong

Graduate Theses and Dissertations

Ultrafiltration (UF) membranes developed out of a need for protein separation processes. Currently, they are used in a variety of industries ranging from food manufacturing to pharmaceuticals for two main purposes: concentration, separation, and buffer exchange. UF membrane processes in product streams undergo frequent use and like all membrane processes experience a gradual decline in performance due to fouling phenomena both irreversible and reversible. Ultimately, performance declines to a point where the UF membrane needs to be replaced. Frequent replacement of UF membranes is detrimental to major industries that require high product throughput using UF processes. Thus, it is important …

Indirect Matrix Converter As Standard Power Electronic Interface, Andrés Escobar-Mejía

Graduate Theses and Dissertations

The increase in the penetration levels of distributed generation in the modern power grid and its importance in future energy systems have accelerated the interest of developing new power electronic interfaces for the energy conversion process. The feasibility of applying the indirect matrix converter as the standard power electronic interface for applications with power ratings from several kW to few MW is addressed in this dissertation. Special attention is given to those applications where space dominates the power electronic requirements. The main motivation for using the indirect matrix converter is that eliminates the energy storage component in the way of …

Photoelectric Characterization Of Bacteriorhodopsin Reconstituted In Lipid Bilayer Membrane, Joel Kamwa

Graduate Theses and Dissertations

The objective of this work was to conduct basic research in biologically inspired energy conversion solutions. A photosynthetic protein (Bacteriorhodopsin) was reconstituted in a bi-layer membrane. Then, when a laser beam was shined on the membrane, the photon energy was used by the protein to pump protons across the membrane. The translocation of protons across the membrane was measured as photocurrent. For this purpose, a system was built to characterize the lipid bilayer membranes and to measure the photocurrent. The lipid bilayer membrane was characterized by its capacitance and resistance. A picoampere photocurrent was observed when Bacteriorhodopsin protein was present …

Metal Assisted Nanowire Growth For Silicon Nanowire/Amorphous Silicon Composite Solar Cell, Asmaa Ali Sadoon

Graduate Theses and Dissertations

Solar cells are photovoltaic devices that convert the energy of light to electricity by the photovoltaic effect. Crystalline silicon-based solar cells are the most dominant solar cells in the market today due to the high efficiency and relatively low cost. However, the cost of such solar cell is still high due to the large amount of material that is consumed in fabricating such a device. Polycrystalline/amorphous thin films and nanomaterial technologies have emerged to reduce the high cost of c-Si based solar cells and increase the efficiency. In this research, we combined these two technologies to propose and fabricate silicon …

Development Of A Heart Rate Variability Measurement System Using Embedded Electronics, Naresh Kumar Velmurugan

Graduate Theses and Dissertations

Recent advances in embedded electronics have a remarkable influence on the health care system. One of the most important applications is to monitor the health care of the patients at anytime and anyplace. In the last two decades, many researchers have focused mainly on heart rate variability (HRV) measurements. Patient's heart rate variability should be continuously monitored to help them in case of emergency. Under these circumstances, patients are required to have a HRV measuring kit for a constant observation.

The proposed project focuses on the development of a heart rate variability measurement system with the use of embedded electronics. …

The Role Of Time And Place In Understanding The Quality Of Life Among Homeless Persons, Gail O'Connor

Graduate Theses and Dissertations

This study examines the role that life chances and choices play in determining quality of life among homeless people. Given the prominent negative impact of homelessness, this paper specifically examines the impact of length of time homeless and location on adverse quality of life. Data from Birmingham, Alabama and Northwest Arkansas Point-in-Time Homeless Census' was utilized and combined to create a sample of 264 homeless individuals. Using a quantitative approach, the topic of adverse quality of life for the homeless is analyzed through a three-model OLS regression, using a life chances and choices framework, with the addition of experiential context--time …

Educator Perceptions Regarding Quality Workplace Professional Development, Darrel Chris Rink

Graduate Theses and Dissertations

This study, Educator Perceptions Regarding Quality Workplace Professional Development, attempted to formulate through interviews and surveys the attitudes of educators regarding their personal experiences with professional development. The study was based on Donald Super's Career Development Theory, Jack Mezirow's Transformational Learning Theory, and David Kolb's Experiential Learning Theory. These three theorists help form the conceptual foundation for the study.

One of the challenges the United States has had within the past fifty years is that workers were not being adequately prepared for the workplace during their school years or after. Super, Mezirow, and Kolb helped to identify stages of growth …

Evaluation Of Low-Tannin Grain Sorghum In Broiler Chicken Diets, Samantha Aniecia Shelton

Graduate Theses and Dissertations

Research trials were conducted to evaluate the effects of different levels of dietary grain sorghum on broiler live performance, carcass yield and shank (leg) and breast skin coloring. Iso-caloric diets were formulated where sorghum replaced corn at rates of 0% (control), 20, 40, 60, 80 and 100% for a total of 6 diets. For each of the two trials, 1500 Cobb 500 male broiler chicks were randomly allocated to 60 pens with 25 birds per pen (10 pens/diet) and grown to 46 days for the first research trial and 41 days for the second. There were no differences (P>.05) …

Recreational Risk Assessment Using Geospatial Analyses On Beaver Lake, Arkansas, Laura Ahrens

Graduate Theses and Dissertations

Accidents and deaths occur regularly on lakes and waterways due to natural phenomena as well as human error and recreation. People use lakes and waterways as sources of recreation, but do not always act responsibly on the water. During summer 2013 and winter 2014, over 100 surveys were administered in Beaver Lake, Arkansas to local and federal agencies regarding their knowledge and perception on accident locations and causes. These surveys were conducted in English and approved by the university after being tested on peers. The surveys included demographic data sex, income, education, as well as Likert-scaled responses. Research was also …

European Consumers' Attitudes Towards Cisgenic Rice, Anne-Cécile Delwaide

Graduate Theses and Dissertations

The enhancement of existing plant breeding techniques, such as cisgenesis, allows plant breeders to enhance an existing cultivar quicker and with little to no genetic drag. Cisgenesis is the genetic modification of a recipient plant with natural gene(s) from a sexually compatible plant. Unlike transgenesis, which is the genetic modification of a recipient plant with gene(s) from any non‐plant organism, or from a donor plant that is sexually incompatible with the recipient plant, the results of cisgenesis could occur naturally over time. Currently, both cisgenic and transgenic products are classified as genetically modified organisms (GMOs) and are labeled as such …

The Cultural Crime Of Femininity: Advocating For Viable And Successful Womanhood In Charles Dickens And George Eliot, Mary K. Leigh

Graduate Theses and Dissertations

Mid-century Victorian England creates an environment for women in which they are expected to adhere strictly to a socially inculcated view of gender and prescribed behaviors. Difficulty arises, however, because women who follow these cultural expectations ultimately fail as they are not given the appropriate skills to function as wives or mothers. On the other hand, women who choose to disregard these social norms for gender are crushed by a cultural policing force that includes both women and men. Thus, prior to legal and educational reforms that allow for women to progress beyond these restrictive gender norms, they are unable …

Gesn Devices For Short-Wave Infrared Optoelectronics, Benjamin Ryan Conley

Graduate Theses and Dissertations

The electronics industry has a large silicon infrastructure for the manufacture of complementary-metal oxide semiconductor (CMOS) based electronics. The increasing density of Si based circuits has set a pace that is now pushing the physical limits of connectivity between devices over conventional wire based links. This has driven the increasing interest in Si based optoelectronics and to use the groundwork already established by the electronics industry for lower cost optical communications. The greatest limitation to this effort has been the incorporation of a Si based laser, which requires integration of a direct bandgap material within this CMOS process.

The Ge1-xSnx …

Career Decision-Making Self-Efficacy: Examining The Effects Of Career Choice, Education, And Work Experience Of Entrepreneurs, Melissa W. Sisco

Graduate Theses and Dissertations

Prior research on the relationship between self-efficacy and career decision making is inconclusive because of the lack of theoretical background and causal conclusions. More research is needed to investigate how the educational background, career choice, and work experience, of entrepreneurs, influences their career decision-making self-efficacy beliefs and how those beliefs effect their decision to become entrepreneurs. The purpose of this study was to investigate to what extent career choice, education, and work experience related to the level of career decision-making self-efficacy among participants in the Ventureprise business incubation program who are or are intending to become entrepreneurs. The education and …

Designing And Implementing A Micro-Controller Based Primary-Side Sensing Flyback Converter For Leds Driver, Nam Nhat Tran

Graduate Theses and Dissertations

The fast development of LED and its applications has enabled a new generation of lighting device with higher efficiency and long lifespan. By employing a primary-side sensing flyback converter and the PIC18F micro-controller series, an LED driver could achieve two important features: (1) the compatibility with the available lighting fixtures, and (2) reducing unit price. The flyback converter was chosen for its simplicity, competitive low cost, and its ability to provide a constant output current, a necessarily important factor to an LED driver. Meanwhile, the PIC18F micro-controller series offer numerous advanced features which include but not limited to pulse-width modulation …

Managing Warehouse Utilization: An Analysis Of Key Warehouse Resources, Vitaly Brazhkin

Graduate Theses and Dissertations

The warehousing industry is extremely important to businesses and the economy as a whole, and while there is a great deal of literature exploring individual operations within warehouses, such as warehouse layout and design, order picking, etc., there is very little literature exploring warehouse operations from a systems approach.

This study uses the Theory of Constraints (TOC) to develop a focused resource management approach to increasing warehouse capacity and throughput, and thus overall warehouse performance, in an environment of limited warehouse resources. While TOC was originally developed for reducing operational bottlenecks in manufacturing, it has allowed companies in other industries, …

Winter Field Pea As A Leguminous Cover Crop In Corn Production, Matthew Carroll Marsh

Graduate Theses and Dissertations

Leguminous cover crops, which fix nitrogen (N) from the atmosphere and add to the N content of the soil, have the potential to replace or partially replace commercial nitrogen fertilizers. In this experiment, field pea (Pisum arvense) was used as the leguminous cover crop in a conventional tilled corn (Zea mays) production system. In a 2-yr experiment (2008 and 2009), conducted at two locations in Arkansas, field pea was planted on half the field in the fall and allowed to grow until late April to early May. Field pea biomass was recorded, N content of biomass determined and then the …

Politics Of Writing: Latin American Testimonio, Brazil's Literatura Marginal And The Question Of Neoliberalism, Ana Maria Todescan Young

Graduate Theses and Dissertations

In the light of Latin American testimonio theoretical approach, which includes questions such as the cultural production under the intensification of neoliberal policies and the inquiry of the complicity between literary practices and the state as formulated by Rama in The Lettered City, this study examines the novel Capão Pecado, representative work of the writer and cultural activist Ferréz, and the potential relation to the formal elements of the former criticism. By thinking alongside John Beverley's case study on I, Rigoberta Menchú's testimonial narrative and Ferréz, prominent author of the contemporary production of literatura marginal and representative of the expression …

Evaluation Of Phytate And Phytase Interactions And Phytase Phase-Feeding On Bird Performance, Bone Characteristics And Meat Quality In Young Growing Broilers, Chance L. Williams

Graduate Theses and Dissertations

Two trials were performed using one-day-old male Cobb x Cobb 500 broilers to determine how dietary phytate and phytase levels as well as phytase phase feeding impacted bird performance parameters, tibia characteristics, and malonaldehyde (MDA) content of the liver, breast and thigh tissues. The first experiment consisted of 1,008 birds randomly placed in 48 floor pens within two commercial broiler houses at the Applied Broiler Research Farm (ABRF; 21 birds per pen; 0.76 ft2 per bird). A 2 X 3 factorial design was used with two levels of dietary phytate (0.21 and 0.31 %) and three levels of phytase supplementation …

The Differentiation And Integration Of Information Technologies: Three Empirical Studies On `Bring Your Own Devices', Zachary R. Steelman

Graduate Theses and Dissertations

This dissertation examines how the management and configuration of organizational IT portfolios enhance organizations and their employees. Specifically, the theory of the differentiation and integration of information technologies is developed with in-depth examinations of "Bring-Your-Own-Device" (BYOD) policies. Four data collections are utilized: survey vignettes, case studies, agent-based simulations, and a questionnaire survey. Each essay uses a mixed-method approach providing insights into the selection, development, and management of ITs across individual and organizational levels.

Essay 1 explores the impact of BYOD on employees' performance, job satisfaction, and work-life conflicts. The results indicate that IT integration improves performance and job satisfaction, and …