Digital Commons Network^™

Smart Surge Irrigation Using Microcontroller Based Embedded Systems And Internet Of Things, Prashant Dinkar Borhade

Graduate Theses and Dissertations

Surge Irrigation is a type of furrow irrigation and one of many efficient irrigation techniques. It is one of the economical techniques and requires minimum labor for monitoring it. In surge irrigation, water is applied intermittently to a field to achieve uniform distribution of water along the furrows, which is important while irrigating, as it ensures that there is enough water near the root zone of the crop. The uneven distribution can cause a loss in crop productivity.

Surge irrigation uses a surge valve, which is an electro-mechanical device that irrigates a field. The commercial surge valves available on the …

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 …

Carbon Sequestration In Grassland Soils Across Arkansas, Marya Jean Mckee

Graduate Theses and Dissertations

The capture, conversion, and long-term storage of carbon dioxide (CO2) as soil organic carbon (SOC), a process known as soil C sequestration, is a possible solution to the current and ever-increasing threat of rising greenhouse gas emissions and global climate change. Tallgrass prairies, which once historically covered the country, are known to accumulate and sequester large amounts of C from the atmosphere deep within the soil, due to their extensive rooting systems. The purpose of this research was to increase understanding of soil C sequestration dynamics and general functioning in disappearing native grassland ecosystems within Arkansas, as well as the …

Mitigating The Risk For Glufosinate Resistance, Christopher John Meyer

Graduate Theses and Dissertations

While glufosinate-resistant weeds have not yet been identified in U.S. row crops, rapid evolution of glyphosate-resistance, and resulting cost to U.S. farmers, demonstrates the need to responsibly steward the limited number of herbicides available in agricultural systems. Field and laboratory experiments were conducted to: 1) Identify herbicide interactions that can occur in Enlist™ and Roundup Ready® Xtend® systems; 2) Identify herbicide interactions that occur when glufosinate is mixed with fomesafen, clethodim, and glyphosate; 3) Determine the optimum rate structure and application timings when multiple POST applications of glufosinate are applied to LibertyLink soybean; 4) Use 14C techniques to determine why …

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. …

Classifying Interdependencies In The Food And Agriculture Critical Infrastructure Sector, John Doerpinghaus

Graduate Theses and Dissertations

This work classifies examples of infrastructure interdependencies found in the food and agriculture critical infrastructure sector. Interdependencies are identified through an examination of rice and poultry agriculture throughout the state of Arkansas. The subtleties of interdependence examples in the food and agriculture sector are inadequately captured by the well-studied interdependence classification taxonomies. Through 39 interviews, we develop an understanding of the subtle temporal, geographic, and productivity scales of interdependence in over 100 examples and present five new, distinct classifications of interdependence: (1) dynamic physical, (2) dynamic geographic, (3) deadline, (4) delay, and (5) human, economic, and natural resource interdependencies. An …

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 …

Imperfect Produce Pricing: Relationships Between Price Percent Discount And Demographic Traits Of Customers, April Foster

Graduate Theses and Dissertations

This research sought to understand the impact of price reductions on consumer spending behaviors related to the purchase of imperfect produce. Additionally, the correlation between consumers’ demographics and their willingness to purchase imperfect produce at various price points was evaluated. The data was viewed with mindfulness toward reducing food loss as a function of the world food crisis. More specifically, the purpose of this study was to describe the relationship between Washington County, Arkansas consumers’ demographic traits and the percent discount at which they are willing to alter their behavior to purchase specific imperfect produce items. Using the Theory of …

Collaborative Robotic Path Planning For Industrial Spraying Operations On Complex Geometries, Steven Brown

Graduate Theses and Dissertations

Implementation of automated robotic solutions for complex tasks currently faces a few major hurdles. For instance, lack of effective sensing and task variability – especially in high-mix/low-volume processes – creates too much uncertainty to reliably hard-code a robotic work cell. Current collaborative frameworks generally focus on integrating the sensing required for a physically collaborative implementation. While this paradigm has proven effective for mitigating uncertainty by mixing human cognitive function and fine motor skills with robotic strength and repeatability, there are many instances where physical interaction is impractical but human reasoning and task knowledge is still needed. The proposed framework consists …

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 …

Budget-Constrained Regression Model Selection Using Mixed Integer Nonlinear Programming, Jingying Zhang

Graduate Theses and Dissertations

Regression analysis fits predictive models to data on a response variable and corresponding values for a set of explanatory variables. Often data on the explanatory variables come at a cost from commercial databases, so the available budget may limit which ones are used in the final model.

In this dissertation, two budget-constrained regression models are proposed for continuous and categorical variables respectively using Mixed Integer Nonlinear Programming (MINLP) to choose the explanatory variables to be included in solutions. First, we propose a budget-constrained linear regression model for continuous response variables. Properties such as solvability and global optimality of the proposed …

Study Of Three Potential Variables That May Impact The Maximum Shear Force And Shear Variation During The Growth And Transport Of Mixed Sex Broilers Grown In Commercial Poultry Houses, Mark Christie

Graduate Theses and Dissertations

Temperature conditions during the transportation to the processing facility of commercial broilers have a direct impact on the meat texture, specifically maximum shear force and shear variation of cooked breast meat. Analysis of a calendar year of flock data (N=346), reveals that the largest impact of transport conditions, specifically temperature, is on the standard deviation of the flocks range of cooked shear values. The optimal transport temperature that yields broiler breast meat with average flock minimum shear and standard deviation values is approximately 60°F. The shear values for flocks at or near 60°F are on average 1 kg less than …

The Impact Of Transfer Shock In A Dental Hygiene Program At A Four-Year Health-Sciences University, Claire Sallee Tucker

Graduate Theses and Dissertations

In order for a student to be successful in dental hygiene education, the student must gain the required knowledge and skills necessary to perform as a hygienist and possess the ability to utilize critical thinking to apply these attributes while in the program and on the National Board of Dental Hygiene Examination (NBDHE) (Alzahrani, Thompson, & Bauman, 2007; Fried, Maxey, Battani, Gurenlian, Byrd, & Brunick, 2017). Dental hygiene students who attend a medical university have the option to take required pre-requisite courses at a community college or a four-year university. All dental hygiene students transfer from another institution and all …

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” …

Intelligent Application Of Flexible Ac Transmission System Components In An Evolving Power Grid, Robert Wall

Graduate Theses and Dissertations

The world revolves around energy and the energy sector is continually transforming and evolving. The status quo has been set by governing agencies in the United States for completely reliable power. The demand for energy efficiency continually rises for multiple reasons. Technology has improved for all sectors of the power grid, including renewable energy sources, fault protection, and SMART grid technology. The addition of new energy sources has led to the decommissioning of inefficient energy sources. The implementation of new technologies and power load on a large scale, coupled with the removal of grid stabilizers has posed different challenges that …

Evaluation Of Rice Stink Bug, Oebalus Pugnax (F.), Damage And Monitoring Techniques In Rice, Oryza Sativa L., And Grain Sorghum, Sorghum Bicolor (L.), Aaron Joseph Cato

Graduate Theses and Dissertations

Rice stink bug, Oebalus pugnax (F.), is a serious pest of headed rice, Oryza sativa L. and an occasional pest of heading grain sorghum in the Mid-south. Work from this dissertation focuses on resolving gaps in and knowledge of rice stink bug sampling and management, and attempts to create a basis for rice stink bug damage assessment in future studies.

Field experiments were conducted from 2016-2018 to asses variation in sweep net sampling by observing producers, researchers, extension personnel, consultants and their workers. Large levels of variation were found in sweep lengths between observed sweepers and reliability of smaller sweep …

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.

The Effectiveness Of Using Video Modeling Techniques To Improve Motor Skills For Preschool Children With Autism Spectrum Disorders, Atya Abdullah Hadadi

Graduate Theses and Dissertations

Beside the main syndromes of socialization and communication for individuals with autism spectrum disorders, they also have impairments in motor skills, such as ball skills (catching and throwing) and postural stability (standing and walking balance). The main objective of this dissertation is to improve motor skills for preschooler children with ASD through use of video-modeling techniques. A secondary objective of this research was to find a correlation between the development and improvement of ball skills and balance tasks. Twenty-six children with ASD were divided into two groups. Twenty-six children with ASD from 3-5 years old participated in two groups: one …

An Rs-485 Transceiver In A Silicon Carbide Cmos Process, Maria Raquel Benavides Herrera

Graduate Theses and Dissertations

This thesis presents the design, simulation and test results of a silicon carbide (SiC) RS-485 transceiver for high temperature applications. This circuit is a building block in the design and fabrication of a digital data processing and control system. Automation processes for extreme environments, remote connection to high temperature locations, deep earth drilling, and high temperature data acquisition are some of the potential applications for such a system. The transceiver was designed and developed in a 1.2 µm SiC-CMOS process by Raytheon Systems, Ltd. (UK). It has been tested with a supply voltage of 12 V and 15 V, temperatures …

Stability Analysis Of A High-Power Microgrid, David Manuel Carballo Rojas

Graduate Theses and Dissertations

The objective of this thesis is to perform the modeling and stability analysis of a high-power microgrid with multiple parallel-and grid connected voltage source converters using the system parameters from the high-power microgrid testbed at the National Center for Reliable Electric Power Transmission (NCREPT) at the University of Arkansas in order to identify, minimize, if not eliminate, the potential instabilities that can affect the proper operation of the microgrid testbed. To achieve this objective, the mathematical modeling of the high-power microgrid considering the adverse effects of resonances due to interactions among the converter LCL output filters is presented and analyzed. …

How Do Instructional Coaches Support The Adult Development Of Teachers, Amanda Carol Linn

Graduate Theses and Dissertations

This case study focused on five Instructional Coaches working in public high schools. The intent of this study was to determine how these Coaches support the adult development of teachers. Three themes emerged from this study: 1) ambiguity regarding the role of Instructional Coaches impacts the performance of Coaches and the adult learners they support, 2) Instructional Coaches struggle to balance the work of supporting adult learners with tasks unrelated to supporting adult learners, and 3) preparation and ongoing professional development for Instructional Coaches is inconsistent in content and frequency.

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 …

Gesn Thin Film Epitaxy And Quantum Wells For Optoelectronic Devices, Perry Christian Grant

Graduate Theses and Dissertations

Group IV photonics is an effort to generate viable infrared optoelectronic devices using group IV materials. Si-based optoelectronics have received monumental research since Si is the heart of the electronics industry propelling our data driven world. Silicon however, is an indirect material whose optical characteristics are poor compared to other III-IV semiconductors that make up the optoelectronics industry. There have been major efforts to integrate III-V materials onto Si substrates. Great progress on the integration of these III-V materials has occurred but incompatibility with CMOS processing has presented great difficulty in this process becoming a viable and cost-effective solution. Germanium …

Why Career And Technical Education Teachers Contribute Intellectual Capital To Open Education Repositories: A Case Study, Kelley J. Manley

Graduate Theses and Dissertations

High quality Career and Technical Education (CTE) teachers are necessary in order to prepare students to fill the gap in the nation’s technical workforce. Technical skills taught by high school CTE teachers assist students as they continue their education in post-secondary technical schools. Post-secondary CTE teachers assist students in their preparation for future high-wage, high-demand technical careers. One of the many challenges reported by CTE teachers is the time-consuming development of relevant curriculum. The open education resource (OER) movement has been reported in research to alleviate some of these challenges for teachers, but research is lacking in the area of …

Effects Of Task Clarification And An Adaptive Computer Software On Implementation Of Mand Training Using An Ipad® As A Speech Generated Device, Ashley Mckenzie Parnell

Graduate Theses and Dissertations

Mand training is an evidence-based instructional method and a primary focus in behavioral language training for children with autism. A rapidly growing research base supports manding training using hand-held computing technologies (e.g., iPad®, iPod®) as speech generating devices (SGD) for establishing a manding repertoire in children with autism. To ensure optimal learning efficacy and efficiency, procedures must be implemented with high levels of accuracy, which requires that staff be well-trained. However, research evaluating methods for training staff to implement mand training procedures with the iPad® and application Proloquo2Go™ as an SGD has not yet been conducted. Therefore, this study examined …

Exploring School Counselors’ Narratives Of Cacrep Accredited Online Education Programs, Rebecca Van Der Hagen

Graduate Theses and Dissertations

Online education is a growing part of academia. The number of online school-counseling programs is also increasing and beginning to include face-to-face and online programs. Little research describes online education and even less discusses online school-counseling programs. The purpose of this study was to examine and interpret participants’ experiences of being trained and graduating from a CACREP online school-counseling master’s program, as well as how their training prepared them for their current role as a school counselor. A qualitative inquiry was conducted to understand online school-counseling programs and reported how six professional school counselors perceived their online program with a …

Teacher Perception And Their Understanding Of Progress Monitoring Throughout A Longitudinal Assessment System, Rena A. Duewel

Graduate Theses and Dissertations

The purpose of this qualitative study was to examine the phenomenon of teacher perception and their understanding of progress monitoring throughout a longitudinal assessment system. This monitoring of student progress is to enhance their academic skills in mathematics and provide necessary interventions for growth as measured on a longitudinal assessment system through fidelity of implementation of interventions processed through progress monitoring. Data was collected from participant responses through interviews, a demographic survey, and focus groups. Interview respondents participated in a closed-door, face-to-face interview. The survey was used to collect specific demographic data to provide a concise snapshot of each individual …

Growth And Behaviors Of Inn/Gan Multiple Quantum Wells By Plasma-Assisted Molecular Beam Epitaxy, Chen Li

Graduate Theses and Dissertations

Fully realizing the potential of InGaN semiconductors requires high quality materials with arbitrary In-content. To this date the growth of In-rich InGaN films is still challenging since it suffers from the low growth temperatures and many detrimental alloying problems. InN/GaN multiple quantum wells (MQWs) and super lattices (SLs) are expected to be promising alternatives to random InGaN alloys since in principle they can achieve the equivalent band gap of InGaN random alloys with arbitrarily high In-content and at the same time bypass many growth difficulties.

This dissertation focuses on studying the growth mechanisms, structural properties and energy structures of InN/GaN …

Essays In Networks Of Finance And Experimental Finance: A Behavioral View, Weineng Xu

Graduate Theses and Dissertations

Behavioral and managerial biases can occur among corporate executives that lead to suboptimal decision making and outcomes for the shareholders. In the first essay, I study how the personal networks of CEO affect the performance of the firm in the context of IPO. I find that CEOs at higher social hierarchical positions can allow managerial entrenchment and prevent dismissal. The findings show that influential CEOs are associated with higher IPO underpricing, lower likelihood of positive offer price revision, and lower likelihood of wealth creation for the pre-IPO shareholders. In the second essay, I explore how the social connections between bidder …

Aiding Growers’ Decisions: Describing Arkansas Blackberry Growers’ Resources And Needs Regarding Blackberry Production, Lesley Marie Smith

Graduate Theses and Dissertations

This study was a census of blackberry growers who attended the Blackberry Growers Association informal interest meetings held throughout the state during the month of April. The purpose of this study was to describe blackberry operations in Arkansas, describe the ideal blackberry cultivar growers want to produce, describe resources they use to research production information, and describe what changes to current resources growers would like to have. Questionnaire responses regarding blackberry production of 18 blackberry growers in the state of Arkansas were analyzed. Three growers elected to not participate resulting in an 86% response rate. The researcher hopes that this …