Digital Commons Network^™

Studies Toward The Development Of A Microelectrode Array For Detection Of Dopamine Through Redox Cycling, Anupama Aggarwal

Graduate Theses and Dissertations

Redox cycling is an electrochemical technique that cycles the reversible redox species between its oxidative states repeatedly on generator and collector electrodes. Two or more individually-addressable microelectrodes located close to each other allow redox cycling to be possible. Electrochemical behavior of a biologically important molecule, dopamine is examined under redox cycling conditions. To our knowledge, this is the first report on detection of physiological concentration of dopamine in presence of up to 100 times excess ascorbate with the use of redox cycling, without the involvement of polymer coating such as Nafion®.

Microfabrication was used to produce different geometries (parallel bands …

Degradation Of Polystyrene Foam Under Radiant Heat Flux, James Butler

Graduate Theses and Dissertations

As the demand for liquefied natural gas has increased, safety concerns about the performance of transport vessels under fire conditions have been raised. Current codes for the sizing of the pressure relief systems require that the vessels are able to withstand an emmissive heat flux of 108kW/m2 and do not take into account the effects of insulation loss due to thermal decomposition of the insulation materials. To address this possible oversight in the current code models were presented to a working group organized by the Society of International Gas Tanker and Terminal Operators Ltd. focusing on the decomposition rate of …

A Multiple Case Study Of Principals' Instructional Leadership In "Level 5" Schools Of Excellence For Improvement, Janice V. Mccoy

Graduate Theses and Dissertations

After 28 years of federal and state policy development, regional and local initiatives and various budgetary appropriations, the status of American schools continues to decline. Lyne (2001) reported that Finland, Japan and Korea had the world's highest literacy in reading, math, and science, while the United States ranked 15 in reading literacy, 19 in mathematical literacy, and 14 in scientific literacy. Many factors may contribute to the decline in America's schools. However, with the prevailing economic decline in the United States schools continue to struggle with student achievement, especially students with who are low socio-economic. In addition, to meeting the …

Can Antioxidant-Rich Berries Improve Risk Factors Associated With Cardiovascular Disease In Postmenopausal Smokers?, Jordan Alaine Teeple

Graduate Theses and Dissertations

The purpose of this study was to examine the effects of smoking on risk factors associated with cardiovascular disease (CVD) and determine the efficacy of antioxidant-rich berries in ameliorating these risk factors in postmenopausal smokers. Menopause and cigarette smoking have been identified as major risk factors for CVD due to a decrease in antioxidant protection, increase in inflammation and oxidative stress, and adverse changes in serum lipids. Antioxidants, specifically flavonoid compounds found in blackberries and blueberries, have been shown to prevent low-density lipoprotein cholesterol oxidation and thus prevent downstream inflammation and oxidative stress. Healthy, postmenopausal nonsmokers (n=14) and smokers (n=31) …

Trafficking Of Women In Nepal: An Intersectional Analysis Of Organizational Narratives, Bhavana Mahat

Graduate Theses and Dissertations

In Nepal, sex trafficking is usually associated with poverty, illiteracy and gender discrimination. To better understand the discursive dimensions of sex trafficking, this research examines the organizational narratives of the Nepalese anti-trafficking workers using the analytical framework of intersectionality. This study finds that the anti-trafficking workers' organizational narratives are influenced by both personal and institutional narratives. In their personal narratives, anti-trafficking workers recognize the multiple forms of discrimination shaping the victims' experiences, but the intersectional discriminations are rarely addressed in the anti-trafficking programs or services implemented by the non-profit organizations. After having identified sex-trafficking victims as experiencing discrimination based on …

Perceptions Of Sexual Dangerousness: Accurate Identification Of Sexual Offenders From Static Photographs, Amber Jean Culbertson-Faegre

Graduate Theses and Dissertations

The present research expands understanding of the phenomenon of accurate identification of sexually dangerous men. Study 1 was designed to examine the influence of experience on accuracy of perceptions of sexual dangerousness. Receiving feedback about test trials increased accuracy on future trials at a marginally significant level. Study 2 was designed to determine the importance of specific facial features on these judgments. This study, however, failed to replicate the findings from the first study. Implications for Study 1, as well as possible explanations for Study 2 are discussed.

Improvements On Just-About-Right (Jar) Scales As Product Optimization Tools Using Kano Modeling Concepts, Bangde Li

Graduate Theses and Dissertations

Attribute Kano characteristics are useful in product design to prioritize development efforts. However, attribute Kano characteristics have not been discussed and applied to product optimization when using Just-About-Right (JAR) scales. Product optimizations without identifying attributes Kano characteristics can be misleading. The two objectives in this research were: 1. Determine attribute Kano categories using a modified classic Kano classification methodology. 2. Propose a method to measure attribute performance and identify attribute Kano characteristics to direct product optimization. Two methodologies of attribute Kano classification were investigated. In experiment one, a modified classic Kano methodology was employed to determine attribute Kano categories through …

Integration Of Racially And Ethnically Diverse Modern Day Military Veterans In American Higher Education, Cedric Mandell Kenner

Graduate Theses and Dissertations

This study focused on examining the integration and transition challenges of racially and ethnically diverse modern day military veterans at a predominantly white research university. Modern day racially and ethnically diverse veterans who have been retained at the institution past their freshman year were invited to participate in the study. Tinto's (1975) Student Integration Model (SIM) served as the theoretical framework for the study which focused on retention and academic support strategies that could be appropriate for racially and ethnically diverse modern day military veterans in American higher education. The methodology utilized in this study was phenomenology which utilized interviews …

Effect Of Nutrient Supplements On Cucumber Fermentation By Lactic Acid Bacteria, Shruti Tripuraneni

Graduate Theses and Dissertations

Lactic acid bacteria (LAB) are important industrial microorganisms involved in fermentation of food and beverage products. The strict fermentative growth of LAB has complex requirements of various nutrients including amino acids, vitamins and minerals. Information about the effect of these nutrients on the growth of LAB in cucumber fermentation is not readily available. It is evident, from previous research that certain nutrients like; leucine, isoleucine, tryptophan, valine, biotin, nicotinic acid, pantothenic acid, riboflavin, manganese and magnesium are beneficial for LAB growth, but are not provided in sufficient quantities by the cucumber in the brine. The objective of this study was …

Community Participation In Post-Tsunami Redevelopment In Aceh: The Process And Community Members' Perceptions And Preferences, Ichsan Ichsan

Graduate Theses and Dissertations

The purpose of this dissertation research is to examine the process of community participation and community members' perceptions of and preferences for the participatory approaches in Aceh post-tsunami redevelopment. The research questions are: (1) How has the process of community participation been implemented in the redevelopment of Aceh Province after the tsunami disaster? (2) What are community members' perceptions of community participation in the redevelopment efforts after the Aceh tsunami? (3) What are community members' preferences for the community participation approaches in the redevelopment efforts after the Aceh tsunami?

I employed qualitative and quantitative methods in this study. The four …

Islands And Swamps: A Comparison Of The Japanese American Internment Experience In Hawaii And Arkansas, Caleb Kenji Watanabe

Graduate Theses and Dissertations

Comparing the Japanese American relocation centers of Arkansas and the camp systems of Hawaii shows that internment was not U\universally detrimental to those held within its confines. Internment in Hawaii was far more severe than it was in Arkansas. This claim is supported by both primary sources, derived mainly from oral interviews, and secondary sources made up of scholarly research that has been conducted on the topic since the events of Japanese American internment occurred. The events of Japanese American Internment in Hawaii and Arkansas are important to remember because they show how far the American government can infringe on …

Water Quality Trends For Section 319 Priority Watersheds In Northwest Arkansas, 1997-2010, Bryan William Bailey

Graduate Theses and Dissertations

Northwest Arkansas contains two Section 319 Priority Watersheds that the Arkansas Natural Resources Commission (ANRC) has identified as being impacted by point and nonpoint sources of pollution (i.e., phosphorus, nitrogen, and sediment), and the Arkansas Water Resources Center (AWRC) has monitored the water quality at several sites within these watersheds. Water-quality data has been collected over the last decade within the Illinois River Watershed (HUC #11110103) and the Upper White River Basin (Beaver Reservoir HUC# 11010001), each watershed containing three sampling sites. The Illinois River Watershed sites are located on the Illinois River, Osage Creek, and Ballard Creek, and the …

The Role Of Leadership In Facilitating The Performance Of Dispersed Teamwork, Jaime Beth Newell

Graduate Theses and Dissertations

A mature body of research on leadership has investigated the impact of a variety of leadership behaviors and styles on team performance. This corpus of work is built on an assumption that team leaders can motivate, direct, and monitor teams by way of sustained, personal contact with team members. However, this assumption is being challenged by recent advances in information and communication technologies (ICTs). Use of ICTs has altered traditional team-based structures, enabling organizations to employ teams composed of members who are dispersed across geographic boundaries, while severing the direct, personal ties leaders have to team members. Recent reviews of …

Modeling And Characterization Of P-Type Silicon Carbide Gate Turn Off Thyristors, Osama Shihadeh Saadeh

Graduate Theses and Dissertations

Silicon carbide (SiC) power semiconductor devices have emerged in the past decade as the most promising technology for next generation power electronic applications ranging for electric vehicles to grid-connected power routing and conversion interfaces. Several devices have been developed, and even some have been released commercially, including diodes, MOSFETs, JFETs, thyristors, gate turn-off thyristors, and IGBTs. The model development, characterization and experimental validation of SiC p-type Gate Turn-off Thyristors (GTO) is presented in this work. The GTO device in this work is being used as part of a SiC-based solid-state fault current limiter under development at the University of Arkansas' …

Geospatial Tools And Techniques For Watershed Management Using Swat 2009, Naresh Pai

Graduate Theses and Dissertations

In this study, geospatial tools and techniques were developed to support specific aspects of watershed pollution management, such as quantifying land-use change (LUC) impacts, prioritizing subwatersheds, and communicating field-scale impacts, using the soil and water assessment tool 2009 (SWAT 2009) model.

For the land-use change objective, a geospatial tool titled SWAT2009_LUC was developed that enables SWAT modelers to prepare specific input files for simulating concurrent land-use changes during the SWAT 2009 model simulations. Testing of the tool for the Illinois River Drainage Area in Arkansas (IRDAA) watershed showed that the tool accurately represented temporal land-uses within the model. Model simulations …

Visualizing The Spatial Localization Of Active Matrix Metalloproteinases (Mmps) Using Maldi Imaging Ms, Sasirekha Muruganantham

Graduate Theses and Dissertations

Biomaterial implantation induces the foreign body response (FBR). Development of longer-term implants relies on the thorough understanding of the FBR. The progression of the FBR is regulated by a number of biomolecules including cytokines, chemokines, and matrix metalloproteinases (MMPs). The nature of the FBR requires the spatial and temporal regulation of these mediators. MMPs are an extremely large and diverse group of enzymes that play key roles in regulating the FBR. Precise spatiotemporal regulation of MMPs defines their proteolytic activities. The aim of this project is to develop a new bioanalytical method to visualize the localization of active MMPs at …

Development Of Spray Cooling For High Heat Flux Electronics, Jeremy Scott Junghans

Graduate Theses and Dissertations

The thermal demands of modern day electronic systems require innovative thermal solutions. Spray cooling has proven to be able to cool heat fluxes orders of magnitude higher than traditional cooling methodologies. This work includes a comparison of spray cooling to standard thermal management methodologies. Key system parameters and considerations are discussed. The properties of available packaging materials and their effect on the reliability of a spray cooled system are presented. Parameters such as fluid temperature, droplet size, fluid velocity and flow rate all directly impact performance and are detailed in this work. Finally, results from of a wide range of …

Design And Fabrication Of Nanofluidic Systems For Biomolecule Characterizations, Orain Ansel Hibbert

Graduate Theses and Dissertations

Nanofluidic channel systems were designed and fabricated by combining MEMS microfabrication with AFM nanolithography. In the fabrication process flow, photolithography was first utilized to pattern microfluidic channels and reservoirs on a 4" Pyrex substrate. Subsequently, atomic force microscopy (AFM) based nanolithography was used to mechanically fabricate nanochannels to connect the microreservoirs which formed the inlet and outlet of the nanofluidic system. A Tap190 Diamond-Like Carbon (DLC) AFM tip with a force constant of 48 N/m and a radius of less than 15 nm was used as the nanolithography tool. The resultant nanochannel ranges from 20 to 80 µm in length …

Nitrogen Retention And Denitrification In Reservoirs, Erin Grantz

Graduate Theses and Dissertations

Studies coupling direct measurements of micro-scale nitrogen (N) cycle processes with ecosystem-scale flux estimates are needed to determine N retention hotspots within river networks, where up to 50% of terrestrial loading to aquatic systems is retained. This study examined the role of denitrification, a microbially-mediated reactive N removal pathway, in ecosystem-scale N retention in 3 small (< 1 km2), shallow flood-control reservoirs. Annual reservoir N retention was estimated through mass balance modeling of system inputs and outputs. Annual denitrification rates were estimated by combining multiple measurements of seasonal, habitat-specific dinitrogen gas (N2) fluxes. Annual reservoir N retention ranged from 14 - 19 g m-2 in the reservoirs, while reactive N removal through denitrification was 13 - 25 g m-2. Denitrification efficiency, or the portion of the retained N load that was denitrified, was high relative to other lentic systems and was > 100% at 2 sites. Previous lentic denitrification studies may have underestimated denitrification efficiency by not considering water column denitrification, which was 50% of total denitrification at one study reservoir. However, not all potential inputs, most importantly biological N2 fixation, were included in this …

Palestinian Film: Hyperreality, Narrative, And Ideology, Sarah Frances Hudson

Graduate Theses and Dissertations

Both sides of the Israeli-Palestinian conflict have developed diametrically opposed national narratives and identities that are both predicated on the concept of victimization. These narratives have developed into simulacral narratives as the result of the nature of their development. This paper deals with the Palestinian simulacral narrative which bolsters societal values, particularly the value of victimhood, that are crucial to coping with the prolonged conflict. The Western media, at any given moment during the conflict, has either accepted the concept of Palestinian's as victims of the conflict and the Palestinian simulacral narrative, or rejected it. The media then produces a …

Modeling Of Sic P-Channel Insulated Gate Bipolar Transistors (Igbts), Mahmood Saadeh

Graduate Theses and Dissertations

A new physics-based IGBT compact model has been developed for circuit simulation of silicon (Si) or silicon carbide (SiC) devices. The model accurately predicts the steady-state output, transfer and switching characteristics of the IGBT under a variety of different conditions. This is the first IGBT model to predict the behavior of p-channel SiC IGBTs. Previous work on IGBT models has focused on Si n-channel IGBTs [1-3]. This unified model is not limited to SiC p-channel IGBTs; the user has the option to select between Si or SiC, and n-channel or p-channel, making it the first IGBT model that captures the …

Crisis Communication Needs Assessment: A Delphi Study To Enhance Instruction For Agricultural Communicators And Other Stakeholders, Allyson Ceary Mcguire

Graduate Theses and Dissertations

Agricultural communicators and industry stakeholders need to be able to develop, prepare and implement crisis communication plans to help assure the sustainability of the agriculture industry should a crisis event occur. A thorough exploration of possible options and needs for training crisis communicators is a needed study in the agriculture industry. Students learning to prepare for managing crises in real life situations are rarely taught in a hands-on, experiential manner. Students can read and analyze case studies pertaining to crises, but without having an actual crisis; little means exist for preparing students for real world situations. There is a need …

Protein Utilization And Requirements In Broiler Breeders, Ricardo David Ekmay

Graduate Theses and Dissertations

Advances in the genetics of poultry have created unintended consequences to the broiler breeder industry. Excessive weight has been shown to have many negative effects, including double hierarchies, multiple ovulations, and fatty liver. In an effort to curb excessive body weight gain, both the protein requirements and feeding strategies of broiler breeders are being revisited. A series of studies were conducted to determine the protein and amino acid requirements of broiler breeders during the production phase and to determine the interrelationship between protein turnover and egg formation. In the first trial, a 2x3x3 factorial study was conducted to determine the …

Photodetectors And Photovoltaic Devices Based On Semiconductor Nanomaterials, Jiang Wu

Graduate Theses and Dissertations

Photodetectors based various nanostructures and plasmon enhanced solar cells are investigated in this dissertation. The motivation of the dissertation rise is driven by urgent need of both high efficiency photodetectors and solar cells.

First, quantum dot infrared photodetectors have been intensely investigated due to their promise in high performance photodetectors. However, the strain-driven growth of quantum dots has hindered the progress of quantum dot photodetectors. The presence of strain in the device presents complexity in designing as well as defects. Therefore, in this project, new designs of quantum dot photodetector structures are presented to improve the control over detection wavelength. …

High Performance Geospatial Analysis On Emerging Parallel Architectures, Seth Warn

Graduate Theses and Dissertations

Geographic information systems (GIS) are performing increasingly sophisticated analyses on growing data sets. These analyses demand high performance. At the same time, modern computing platforms increasingly derive their performance from several forms of parallelism. This dissertation explores the available parallelism in several GIS-applied algorithms: viewshed calculation, image feature transform, and feature analysis. It presents implementations of these algorithms that exploit parallel processing to reduce execution time, and analyzes the effectiveness of the implementations in their use of parallel processing.

Subcritical Water Hydrolysis Of Whey Proteins, Ashley Dawn Espinoza

Graduate Theses and Dissertations

Hydrolyzing food by-products is a unique approach to potentially increase by-product value and reduce waste. An abundant by-product of cheese production, whey, contains all essential amino acids and some distinctive peptides with functional and nutraceutical properties. Typically, proteins from whey are tailored for specific uses by chemical or enzymatic hydrolysis; however, subcritical water hydrolysis is a novel alternative used successfully to hydrolyze various substrates. Nevertheless, minimal research exists on: (1) the hydrolysis of whey protein; (2) the incorporation of additives; (3) the hydrolysis of whole whey; and (4) the production of volatiles when using subcritical water hydrolysis.

Therefore, whey protein …

The Incidence Of Plexiform Lesion Formation In Lines Divergently Selected For Ascites, James Grant Mason

Graduate Theses and Dissertations

Complex Vascular Lesions, (CVL) are a common vascular change associated with idiopathicpulmonary arterial hypertension (IPAH). CVL have been characterized in studies using animal models involving, but not limited to, Sprague-Dawley rats and poultry (Abe et al., 2010; Wideman et al., 2011).IPAH has been documented in poultry although no connection has been made with CVLs. The current study characterizes CVL in the lungs from broilers derived from lines divergently selected for 15 generations for ascites susceptibility under conditions of simulated high altitude. The ascites RES and SUS lines were sampled for CVL incidence over time. Both lines were reared in a …

Disclosing An Invisible Disability During The Interview Process: A Qualitative Study, John Elias Sassin

Graduate Theses and Dissertations

Rehabilitation professionals, persons with disabilities and employers were asked to participate in a focus group interview exploring the phenomena of disclosing invisible disabilities during the interview process. This Qualitative study examined disclosure of disability from each stakeholder's perspective in an effort to understand its impact on the interview. After transcribing the focus group interview and analyzing the data; five themes emerged reflecting each stakeholder's views on disclosure. The themes revealed the persistence of attitudinal barriers that people with disabilities face in seeking employment; if and when a person should disclose; what are the positive and negative aspects of disclosure and …

Investigation Of A Floating Load Buck Dc-Dc Switching Converter, Hong Tan

Graduate Theses and Dissertations

A floating load buck DC-DC switching converter was analyzed, simulated, designed and prototyped. The floating load buck converter is first compared to the conventional buck converter. It was found that both the floating load buck converter and conventional buck converter exhibit similar conversion characteristics despite the differences in the placement of their output inductors. A floating load buck converter was designed to be used as a high-voltage off-line light-emitting diodes (LEDs) driver using a Texas Instruments' TPS92001 controller. Finally, the characteristics of this floating load buck converter LED driver were experimentally examined.

Design Of A Low Noise Amplifier For Wireless Sensor Networks, Ting Liu

Graduate Theses and Dissertations

CMOS technology becomes important in Radio Frequency (RF) communication systems which include both a receiver and a transmitter. In a high performance radio receiver, the Low Noise Amplifier (LNA) is the first circuit, and its noise performance dominates the entire receiver. Depending upon the system in which they are used, LNAs can be designed according to various topologies and structures. The LNA needs to have matched input impedance, and at the same time it should amplify the small amplitude input signal without adding too much noise and still have the minimal power consumption. It also needs a good interface with …