Digital Commons Network^™

Utilizing The Hvsr Second Peak For Surface Wave Inversions In The Mississippi Embayment, Ashraf Kamal Himel

Graduate Theses and Dissertations

Ambient noise data from 24 sites within the Mississippi Embayment were analyzed to estimate the fundamental frequency using the horizontal to vertical spectral ratio (HVSR) method. The fundamental frequency ranged from 0.17 to 3.43 Hz for the tested sites. At seventeen of the sites, a second higher frequency HVSR peak, which ranged from 0.617 Hz to 2.154 Hz, was observed in addition to the fundamental HVSR peak. The second peak frequency in the HVSR curve has been attributed by previous researchers as either an odd harmonic of the fundamental peak or a shallow impedance contrast from the Memphis sand layer …

Interfacial Tailoring Of Lithium-Ion Batteries By Atomic/Molecular Layer Deposition, Qian Sun

Graduate Theses and Dissertations

Lithium-ion batteries (LIBs) are promising energy storage devices, which play significant roles in addressing problems related to fossil fuels depletion and environmental pollution. Since the 1990s, LIBs have attracted great attention for many applications. Nowadays, LIBs are dominating portable electronics, having several advantages over their forerunners, such as high voltage (3.3~4.2 V) [1,2], low self-discharge (< 5~10 %/month) [3,4], wide operation temperature (-20~60 °C) [5,6], and fast charge/discharge rate [7,8]. However, LIBs deliver an energy density of 100-220 Wh/kg in practice to date, which is far from their theoretical ones, thus hindering their further applications in electric vehicles. Additionally, LIBs have been plagued by other problems, such as intolerance to overcharge/overdischarge, low heat resistance, lithium dendrites growth, large volume change of the silicon anode, large polarization and even safety problems.

Atomic layer deposition (ALD) and molecular layer deposition (MLD) are two important techniques, both proceeding in self-limiting gas-solid reactions and exhibiting excellent capabilities for ultra-thin films, conformal coatings, and controllable growth. They can be employed to address the problems of LIBs mentioned above by …

Examining The Use Of Idealized Granular Material In Validated Dem Simulations, Anjana Thoroppady Kittu

Graduate Theses and Dissertations

Discrete element method (DEM) modeling, is becoming widely used for understanding the micro-mechanical behavior of granular materials at the particle level. This dissertation presents important considerations regarding the experimental boundary conditions and idealized granular materials used in DEM validations.

A common issue in DEM validation studies for direct shear and direct simple shear is selecting top and bottom cap boundary conditions that allow for shear transmission while also being efficiently modeled in the DEM simulations. While the traditional grid boundary types used in the laboratory can be replicated in the numerical models, researchers have also used fixed-particle boundaries, sawtooth boundaries, …

Developing Computer Codes For Analyzing Bridge Response Due To Wim Data Truck Loading, Kenneth Patrick Pasley

Graduate Theses and Dissertations

Despite actual truck demographics evolving over the past 30 years, the Arkansas legal loads for bridge posting have not been updated. Custom computer codes were developed.to facilitate comparison between the current Arkansas legal loads for bridge posting and the actual Arkansas truck traffic to ensure that actual reactions are enveloped by the state'. The program, WIMFluence, calculates shear and moment influence lines for a bridge and the resulting shear and moment reactions based on weigh-in-motion data. With supporting scripts, the reactions due to actual Arkansas truck traffic were compared to those due to the current Arkansas legal loads for bridge …

Utilizing 3d Printed Analogue Soils To Investigate Specimen Size Effects In Triaxial Testing, Claire Louise Stewart

Graduate Theses and Dissertations

Triaxial testing is one of the fundamental laboratory tests used in geotechnical engineering to determine strength parameters, such as shear strength and friction angle. Investigating the minimum representative elementary volume (REV) can verify the independence of size effects on strength parameters and ensure that the scaled laboratory tests results are consistent, repeatable, and representative of field conditions. Although, REV has been studied for many applications, there is disagreement within geotechnical engineering of a minimum particle diameter to specimen diameter to minimize the size effects related to the REV in consolidated drained (CD) triaxial tests. This research study compared the strength …

Assessing Biofiltration Without Ozonation For Removal Of Trihalomethane Precursors In Drinking Water At The Beaver Water District Drinking Water Treatment Plant, Sana Ajaz

Graduate Theses and Dissertations

Biofiltration without pre-ozonation has the capability to remove natural organic matter (NOM) fractions that serve as precursors of disinfection byproducts (DBPs), which include the four regulated trihalomethanes (THMs) and dichloroacetonitrile (DCAN). Rapid small-scale column tests (RSSCTs) and Pilot Plant filters operated at empty-bed contact times (EBCTs) of 4, 8, and 16 minutes were used to evaluate the performance of nutrient-amended (free ammonia and phosphorus) biofiltration for THM and DCAN precursor removal, as measured using formation potential (FP) tests. NOM surrogates – which include dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA254) and fluorescence-PARAFAC components – were measured weekly throughout the …

The Role Of Information Communication Technologies (Icts) In Shaping Identity Threats And Responses, Mary Macharia

Graduate Theses and Dissertations

With the rising use of social media, people are increasingly experiencing, and responding to, identity threats online. This sometimes leads to online backlash via “cybermobs” or the creation of online social movements that traverse offline. Prior information systems (IS) research on identity threats and responses largely focuses on information communication technology (ICT) implementations within organizations in an offline context. Therefore, we lack understanding of ICT-mediated identity threats and responses and ways to promote healthier and productive interactions online. This two-essay dissertation seeks to fill this gap. Essay 1 combines a review of ICT-mediated identity threats with a qualitative study (based …

Synthesis Of Dicamba Glucosides For The Study Of Environmental Dicamba Drift Effects On Soybeans, Holly Wallace

Graduate Theses and Dissertations

The most popular herbicide used for weed control has been glyphosate for many years in the Midwestern United States. Plants have begun to develop a resistance to glyphosate due to over use of the herbicide. This herbicide resistance has pushed farmers to turn to alternative herbicides such as dicamba and 2,4-D. Recently agrochemical companies have developed genetically modified crops that are resistant to herbicides such as dicamba. These modified crops allow farmers to spray their fields with dicamba without fear of crop damage. Farmers of non-genetically modified crops, however, suffer damage and loss of yield from herbicide drift effects of …

A Support Program For College Students With Autism Spectrum Disorder: The Functioning Of Participants Versus Non-Participants And The Role Of Program-Sponsored Mentoring, Ayla Raven Mapes

Graduate Theses and Dissertations

Increasingly more students with autism spectrum disorder (ASD) are attending college. In response, many colleges are now offering these students the extra support of an Autism Support Program (ASP), many of which include a mentoring component. This study is one of only a handful of attempts to examine these programs empirically. Using a small sample of college students who identified as having ASD, I compared participants and non-participants of a university ASP. An online survey was used to assess demographic characteristics and pre-college academic performance, as well as students’ functioning across the following domains: social, adaptive, academic, emotional, and having …

Irish Whips And German Suplexes: Professional Wrestling And The American Immigrant And Minority Experience, Colin Rush Walker

Graduate Theses and Dissertations

Trends within sports and popular entertainment have long been regarded as great indicators of larger transitions in the social, political, and economic landscape of the United States. Repeatedly mined and often used for context, sports have become intrinsically linked to the broader discussions of people, their beliefs, ideals, and actions occurring in the historiography of American culture. However, one sport has regularly been passed over in these examinations. I argue that the modern day entertainment monolith of professional wrestling serves as one of the most important indicators of socioeconomic change in the history of the U.S., and that it plays …

Aqueous Ozone Inactivation Of Viruses And Bacteria On Biotic And Abiotic Surfaces, Cailin Dawley

Graduate Theses and Dissertations

Produce is susceptible to contamination by foodborne pathogens. Food service establishments utilize sanitizing agents to reduce microbes on produce surfaces. The research objectives were to evaluate the efficacy of aqueous ozone 1) on the inactivation of viruses and bacteria on produce; 2) on the inactivation of viruses on stainless steel; and 3) against viruses in association with bacteria on produce surfaces. For objective 1, Boston bibb lettuce and cherry tomatoes were spot inoculated with a cocktail of viruses (murine norovirus (MNV) and MS2 bacteriophage) or bacteria (Enterobacter cloacae and Bacillus cereus) and washed for 40 min with samples taken every …

Understanding The Relationship Between Corporate Social Responsibility, Team Identification, And Behavioral Intention With The Mediating Effect Of Satisfaction In Korean Professional Baseball League, Jaeman Son

Graduate Theses and Dissertations

The purpose of this dissertation was to provide a better understanding of how sport fans’ perceptions of a sport team’s CSR activities influence the behavioral intention of sport consumers. More specifically, the aim of this study was to propose and test a theoretical model that explore the relationship among perceived CSR and team identification and satisfaction, along with the behavioral intention. This study was to investigate the mediating role of customer satisfaction in the relationship between perceived CSR and behavioral intention. Finally, the study attempts to examine whether the relationship between team identification and behavioral intention is mediated by customer …

Risky Business: Millennials’ Protection Motivation Factors For Norovirus Outbreaks On College Campuses, Dylan Conrad Martinez

Graduate Theses and Dissertations

The risk and severity of hNoV transmission is obscurely recognized to foodservice millennial customers. Most commonly associated with cruise ships, consumers are not aware of its full potential to strike at other locations, especially college campuses. For the foodservice industry and the university community, it is imperative that a proactive method for increasing millennials’ motivation to practice mitigation methods emerges to reduce future hNoV outbreaks on college campuses. Research has shown that students can play a major role in the spread of hNoV on college campuses. Therefore, the purpose of these studies is to examine motivations for health protective behaviors …

Access To Children's Books Featuring Characters With Disabilities, Jacquelyn Thompson

Graduate Theses and Dissertations

Shared reading and access to print have been linked to improved outcomes for young children and linked to socio-economic status (e.g Neuman, 1999; Zucker, Cabell, Justice, Pentimonti & Kaderavek, 2013). As a community, we know very little about the access to books that the diverse population of preschool age children from Northwest Arkansas have. Moreover, we know very little about the type of books available to them. This study seeks to understand how many children’s books are in select preschools of varying socioeconomic status within Northwest Arkansas that service those with and without disabilities. More pointedly, within the children’s book …

Effect Of Cooking Method On Meat Texture In Normal And Woody Broiler Breast Fillets Using Instrumental Analysis And Descriptive Sensory Analysis, Lynda D. Combs

Graduate Theses and Dissertations

Over the past few decades, broiler breast meat has changed in terms of meat quality. Meat quality has deteriorated with the rise in the occurrence of muscle myopathies. Conditions such as woody breast, which is described as pale and bulging areas of distinct hardness, compromise both the textural and technological traits that have been associated with breast meat. The Meullenet-Owens Razor Shear (MORS) method is a common method for indirectly assessing poultry meat tenderness. A blunt version of the MORS (BMORS) has been shown to be a more sensitive method at higher degrees of toughness. A slightly larger stainless steel …

Optimizing The Plasmonic Enhancement Of Light In Metallic Nanogap Structures For Surface-Enhanced Raman Spectroscopy, Stephen Joseph Bauman

Graduate Theses and Dissertations

Technology based on the interaction between light and matter has entered something of a renaissance over the past few decades due to improved control over the creation of nanoscale patterns. Tunable nanofabrication has benefitted optical sensing, by which light is used to detect the presence or quantity of various substances. Through methods such as Raman spectroscopy, the optical spectra of solid, liquid, or gaseous samples act as fingerprints which help identify a single type of molecule amongst a background of potentially many other chemicals. This technique therefore offers great benefit to applications such as biomedical sensors, airport security, industrial waste …

Undergraduate Students’ Perceptions Of Their International Teaching Assistants (Itas) And Perceptions Of Themselves In A Course(S) Instructed By An Ita, Nadia Hanayeen

Graduate Theses and Dissertations

The University of Arkansas is a large, diverse public university. International teaching assistants (ITAs) represent 20% of the total graduate teaching assistants at the University of Arkansas. In the Fall semester of 2015, the University of Arkansas ranked 9th among U.S. universities based on the number of ITAs instructing undergraduate classes. Combining quantitative and qualitative data collection and analysis methods, this study investigated domestic undergraduate students’ perceptions of their ITAs and of themselves in courses instructed by ITAs. The descriptive quantitative findings showed that the two most significant challenges facing ITAs are American students’ perceptions of their pedagogical skills and …

Margaret White Springs Recharge Study, Buffalo National River, North-Central Arkansas, Usa, Ashlon Elizabeth Leonard

Graduate Theses and Dissertations

Margaret White Springs (MWS) is one of the largest springs in the middle section of the Buffalo National River (BNR) and contributes several tens of cubic feet per second of flow to river discharge on average, yet the source of the water has not been fully studied or documented. The spring is located approximately 4 miles downstream from Robertson Hole, a losing reach of the river. At Robertson Hole the river loses a significant amount of flow to groundwater, which during the dry season (summer) can be as much as 100%. Flow in the main channel is re-established at MWS; …

Development Of A Methodology For Predicting Consumer Acceptance And Preference Toward Beverages, Shilpa Shailesh Samant

Graduate Theses and Dissertations

Consumer behavior toward food/beverages is influenced by multisensory attribute perceptions as well as emotional experiences. Traditional methods of sensory testing lack the ability to capture emotional responses and as a result, measuring food/beverage-evoked emotions remains a research challenge. There were three objectives of this dissertation study. Firstly, this study aimed to develop prediction models of acceptance of and preference for basic taste solutions using sensory attribute intensities and emotional responses. Secondly, this study aimed to extend the findings of the first objective to develop prediction models of commercially-available vegetable juice products in terms of (a) acceptance and preference under blind-tasting …

Acculturation And Internalizing Problems Among Latino Youth: A Meta-Analytic Review, Juventino Hernandez Rodriguez

Graduate Theses and Dissertations

Some studies have found acculturation to be a positive predictor of internalizing problems (i.e., anxiety and depression) in Latino youth (Gonzales et al., 2002), whereas other studies have revealed no relation or a negative relation between acculturation and internalizing problems (Smokowski, Buchanan, & Bacallao, 2009). Narrative reviews of this literature exist (Gonzales et al., 2002; Gonzales et al., 2009) but a quantitative synthesis of the literature has not been conducted. After a systematic literature search that identified 38 studies meeting inclusionary criteria, a meta-analysis was performed to estimate the size and direction of the relation between acculturation and internalizing problems. …

Risk And Return Comparisons Of Pre-Harvest Marketing Strategies, John Leander Turner V

Graduate Theses and Dissertations

This paper analyzes risk and returns associated with pre-harvest corn grain marketing strategies for the state of Arkansas. Farming is characterized by a volatile environment. Numerous risks are taken by producers in order to provide commodities that are bought and sold by various parties in the supply chain. Price, yield, and production costs vary daily and can have large variation between years. Risk and Return Comparisons of Pre-harvest Marketing Strategies examines the effectiveness of using pre-harvest marketing strategies to enhance returns and to mitigate inherent price risk in the Memphis cash corn market. Thirteen strategies are compared to the October …

Counter-Revolution And Egypt’S Lower Middle Class, Keith Glenn Whitmire

Graduate Theses and Dissertations

The Egyptian lower middle class has been declining since the 1970s. Yet since the 2011 uprising and coup d’état the lower middle class has sat in the midst of an economic and political counter-revolution carried out by the police, the military, and Egypt’s intelligence services. In particular, President Abdel Fattah al-Sisi has responded to Egypt’s economic crisis in 2014 and onward by engaging in a program of austerity has sped the decline of the Egyptian lower middle class significantly. The Egyptian lower middle class is in increasing danger of becoming merely educated working poor. Therefore this dissertation will examine the …

Systems To Attract And Feed Pollinators In Warm-Season Lawns, Michelle Wisdom

Graduate Theses and Dissertations

Pollinating insects are responsible for the production of many agricultural crops and they require floral resources to fulfill their life-cycle. Ideally, pollinating insects will encounter a diversity of floral resources across their entire season of activity, and those floral resources can include both herbaceous and woody plant species. Managed turfgrass areas have been identified as potential locations for creating pollinator-friendly habitats. In the transition zone, where both warm- and cool-season turfgrass species are present, the persistence of herbaceous plants in warm-season turfgrasses such as bermudagrass (Cynodon spp.) and buffalograss (Buchloe dactyloides), may be affected not only by the competitive nature …

Speleogenesis In Turbulent Flow, Max P. Cooper

Graduate Theses and Dissertations

Existing models of speleogenesis neglect the shape of cross-sections, which can hold information related to climate, tectonics, and sediment supply in their widths. The first study of this dissertation simulates cross-sections of phreatic tubes, vadose canyons, and paragenetic galleries using a method developed for bedrock channels. Successful simulation of these cross-sections depends on erosion scaling with shear stress, in conflict with speleogenesis theory. Scaling of equilibrium width in paragenetic galleries was explored through analytical derivation and simulations, showing that width scales positively with discharge to the 1/2 power, and negatively with a weak power of sediment supply. Negative scaling of …

Periodicals In Transition: Politics And Style In Victorian Higher Journalism, David Blaine Walker

Graduate Theses and Dissertations

Covering a period roughly from the mid-1820s through the early-1880s, this dissertation investigates transformations in the style and substance of political discourse practiced in British organs of “higher journalism.” Animating certain key moments and figures along the way, it explains the shift from a periodical market dominated by the anonymous, lengthy treatises found in quarterly reviews like the Edinburgh Review (f. 1802) and its rivals, to an industry dominated by monthly reviews that generally eschewed both the anonymity of its contributors as well as the prohibitive length of its predecessors. In exploring this transition from the “Age of the Quarterlies” …

Quantitative Microbial Risk Assessment For Parts, Ground, And Msc Poultry Product Including Intervention Analysis And Exploration Of Enterobacteriaceae As An Indicator Organism In Poultry Processing, Leigh Ann Parette

Graduate Theses and Dissertations

Samples collected at five different large bird poultry processing facilities over a period of 7 months from prescald to post debone locations were enumerated for Enterobacteriaceae, Salmonella spp., and Campylobacter spp. and the results were used to create Quantitative Microbial Risk Analyses (QMRA) models for parts, ground, and mechanically separated chicken (MSC) products. Sensitivity analyses indicated the points in the process at which reductions would be most advantageous to the endpoint and simulation models were run to test reductions required to meet the current USDA performance standards.

These data were analyzed to determine the reductions from one node (location) to …

Identifying Opportunities That Promote A Habit Of Mind In The Quantitative Reasoning Classroom., David Lavie Deville

Graduate Theses and Dissertations

Quantitative literacy and its role in a democratic society are emerging topics of concern to mathematics educators throughout the world. Undergraduate courses in Quantitative Reasoning (QR) are a recent addition to the growing list of resources aimed at remedying quantitative illiteracy in America. Students were interviewed after completing three different undergraduate QR courses. A qualitative analysis of the interviews as well as course texts identified opportunities and hindrances for students in developing a habit of mind toward QR, how students apply a habit of mind, and obstacles students faced in developing a habit of mind.

Assessment Of Salmonella Enterica Biofilms And Expression Differences Among Serovars, Zhaohao Shi

Graduate Theses and Dissertations

Biofilms are communities of microorganisms associated by a matrix of extracellular polymers. In this state, microorganisms occupy an ecological niche distinct from their free-floating, planktonic counterparts. Also, biofilm bacteria become biologically unique as they form communities and lose motility. The acquisition of these physiological attributes enables the biofilm to persist through harsh environmental conditions, including antimicrobial induced stress and to resist sanitization efforts. Because of these features, biofilms can rapidly disseminate across numerous surfaces and as they establish, become challenging to remove. This is a particular issue for the food industry as processing plants offer favorable conditions for biofilm formation …

Genetic And Genomic Analyses Of Bacterial Responses To Different Stress Environments, Sakshi Rampal

Graduate Theses and Dissertations

Bacteria encounter a plethora of environmental stresses and have evolved different mechanisms to recognize and respond to various harmful conditions. Understanding and elucidating common themes as well as unique aspects of the molecular mechanisms underlying stress adaptation is important and can provide valuable strategies for applications. This study focuses on stress responses in three different bacteria, namely, Acidothermus cellulolyticus, Mycobacterium smegmatis and Escherichia coli. The thermophilic and acidophilic organism A. cellulolyticus was used as a model system to understand the effects of lignin phenolic acids on cellulolytic bacteria. Lignin phenolic acids pose a significant challenge to microbial deconstruction of lignocellulosic …

Revision Of The Genus Monatractides (Parasitengona, Torrenticolidae) Of The United States And Canada: New Species, Re-Descriptions, Phylogenetics, And A Key To Species, Whitney Anne Nelson

Graduate Theses and Dissertations

The full suite of known Monatractides (Parasitengona, Torrenticolidae) taxa of North America (north of Mexico) are investigated herein using integrative methods. Species hypotheses are supported with morphology, geography, and phylogenetic analysis of the barcoding region of COI for 154 individuals from over 100 localities. Relationships between species are examined with a combined analysis of COI and 28S rDNA for 55 specimens. Previously described species are examined and re-described with color images and updated information, where possible. Our results indicate the need to synonymize two species: M. californica (Marshall, 1943) is a junior synonym of M. geographica (Marshall, 1943). We describe …