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Academic and Social Functioning of College Students with Attention-Deficit/Hyperactivity Disorder (ADHD) (open access)

Academic and Social Functioning of College Students with Attention-Deficit/Hyperactivity Disorder (ADHD)

Attention-deficit/hyperactivity disorder (ADHD) is a complicated psychiatric disorder that is typically first diagnosed in childhood and associated with negative outcomes in adulthood such as poor academic performance and difficulties with social relationships. ADHD can be difficult to accurately diagnose in adulthood, given the absence of clear, agreed upon ADHD symptomology in adults. In the current study, two raters used psychometrically sound instruments and diagnostically valid assessment techniques on an archival dataset to create three distinct groups: ADHD [2/3 with other mental health diagnosis (OMH)], OMH only, and no diagnosis. Findings support the value of comprehensive assessment, combined with a thorough evaluation of the material by a trained clinician, for the accurate diagnosis of ADHD for research purposes. Comparisons were made across groups to infer that college students with ADHD have lower grade point averages and academic self-concept than students without mental health diagnoses. Yet, contrary to much of the current literature, college students with ADHD seem to create as strong, deep, supportive and harmonious relationships with loved ones and close friends as their non-diagnosed peers. Clinicians working with college students with ADHD may use the results of the current study to better inform conceptualization, better recognize the innate resilience college …
Date: December 2017
Creator: Calmenson, Nina
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Academic Stress in Student-Athletes (open access)

Academic Stress in Student-Athletes

Academic stress and the causes of such stress are subjects that are found in very few studies concerning student-athletes. Therefore, the purpose of this quantitative study is to determine how the following variables relate to academic stress and perceived stress either through correlations or differences--demographics, academic classification, major or field of study, athletic scholarship status, and season of sport (in- season/ out of season). An online questionnaire containing a Perceived Stress Scale and a Perception of Academic Stress scale were distributed to 151 student-athlete participants at a university in the southwest United States. The results indicated that biological sex has a significant relationship to perceived stress. No other variables were found significant to perceived stress or academic stress.
Date: May 2017
Creator: James, Christina
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Additive Manufacturing of Metastable Beta Titanium Alloys (open access)

Additive Manufacturing of Metastable Beta Titanium Alloys

Additive manufacturing processes of many alloys are known to develop texture during the deposition process due to the rapid reheating and the directionality of the dissipation of heat. Titanium alloys and with respect to this study beta titanium alloys are especially susceptible to these effects. This work examines Ti-20wt%V and Ti-12wt%Mo deposited under normal additive manufacturing process parameters to examine the texture of these beta-stabilized alloys. Both microstructures contained columnar prior beta grains 1-2 mm in length beginning at the substrate with no visible equiaxed grains. This microstructure remained constant in the vanadium system throughout the build. The microstructure of the alloy containing molybdenum changed from a columnar to an equiaxed structure as the build height increased. Eighteen additional samples of the Ti-Mo system were created under different processing parameters to identify what role laser power and travel speed have on the microstructure. There appears to be a correlation in alpha lath size and power density. The two binary alloys were again deposited under the same conditions with the addition of 0.5wt% boron to investigate the effects an insoluble interstitial alloying element would have on the microstructure. The size of the prior beta grains in these two alloys were reduced …
Date: August 2017
Creator: Yannetta, Christopher James
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Adrenergic and Cholinergic Regulation of Cardiovascular Function in Embryonic Neotropic Cormorants (Phalacrocorax basilianus) (open access)

Adrenergic and Cholinergic Regulation of Cardiovascular Function in Embryonic Neotropic Cormorants (Phalacrocorax basilianus)

Investigations of cholinergic and adrenergic tone on heart rate (fH) and mean arterial pressure (Pm) during embryonic development have been conducted on numerous avian species. While these investigations have documented that adrenergic tone, a continuous stimulation, on fH and Pm is vital to embryonic development in the birds studied to date, development of cholinergic tone on fH has been shown to vary even within species. Further, past studies have been bias to focus primarily on precocial species while altricial species remain poorly understood in this context. The goal of this investigation was to investigate the role of cholinergic and adrenergic tone on fH and Pm of an altricial species, the neotropic cormorant (P. brasilianus) to address this bias. The embryonic neotropic cormorant possesses B-and-a adrenergic tone on fH and Pm at 70% and 90% incubation while cholinergic tone on fH occurs at 90% incubation. This pattern of control is similar to that previously reported for several species of precocial birds suggesting the development of tonic cardiovascular regulation may be conserved across avian taxa.
Date: May 2017
Creator: Cummins, James B.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Analysis of Heat Transfer Enhancement in Channel Flow through Flow-Induced Vibration (open access)

Analysis of Heat Transfer Enhancement in Channel Flow through Flow-Induced Vibration

In this research, an elastic cylinder that utilized vortex-induced vibration (VIV) was applied to improve convective heat transfer rates by disrupting the thermal boundary layer. Rigid and elastic cylinders were placed across a fluid channel. Vortex shedding around the cylinder led to the periodic vibration of the cylinder. As a result, the flow-structure interaction (FSI) increased the disruption of the thermal boundary layer, and therefore, improved the mixing process at the boundary. This study aims to improve convective heat transfer rate by increasing the perturbation in the fluid flow. A three-dimensional numerical model was constructed to simulate the effects of different flow channel geometries, including a channel with a stationary rigid cylinder, a channel with a elastic cylinder, a channel with two elastic cylinders of the same diameter, and a channel with two elastic cylinders of different diameters. Through the numerical simulations, the channel maximum wall temperature was found to be reduced by approximately 10% with a stationary cylinder and by around 17% when introducing an elastic cylinder in the channel compared with the channel without the cylinder. Channels with two-cylinder conditions were also studied in the current research. The additional cylinder with the same diameter in the fluid channel …
Date: December 2017
Creator: Kota, Siva Kumar k
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Application of High Entropy Alloys in Stent Implants (open access)

Application of High Entropy Alloys in Stent Implants

High entropy alloys (HEAs) are alloys with five or more principal elements. Due to these distinct concept of alloying, the HEA exhibits unique and superior properties. The outstanding properties of HEA includes higher strength/hardness, superior wear resistance, high temperature stability, higher fatigue life, good corrosion and oxidation resistance. Such characteristics of HEA has been significant interest leading to researches on these emerging field. Even though many works are done to understand the characteristic of these HEAs, very few works are made on how the HEAs can be applied for commercial uses. This work discusses the application of High entropy alloys in biomedical applications. The coronary heart disease, the leading cause of death in the United States kills more than 350,000 persons/year and it costs $108.9 billion for the nation each year in spite of significant advancements in medical care and public awareness. A cardiovascular disease affects heart or blood vessels (arteries, veins and capillaries) or both by blocking the blood flow. As a surgical interventions, stent implants are deployed to cure or ameliorate the disease. However, the high failure rate of stents has lead researchers to give special attention towards analyzing stent structure, materials and characteristics. Many works related to …
Date: May 2017
Creator: Alagarsamy, Karthik
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Application of UV-Vis Spectroscopy to the Monitoring, Characterization and Analysis of Chemical Equilibria of Copper Etching Baths (open access)

Application of UV-Vis Spectroscopy to the Monitoring, Characterization and Analysis of Chemical Equilibria of Copper Etching Baths

The continuously increasing demand for innovation in the miniaturization of microelectronics has driven the need for ever more precise fabrication strategies for device packaging, especially for printed circuit boards (PCBs). Subtractive copper etching is a fundamental step in the fabrication process, requiring very precise control of etch rate and etch factor. Changes in the etching chemical equilibrium have significant effects on etching behavior, and CuCl2 / HCl etching baths are typically monitored with several parameters including oxidation-reduction potential, conductivity, and specific gravity. However, the etch rate and etch factor can be difficult to control even under strict engineering controls of those monitoring parameters. The mechanism of acidic cupric chloride etching, regeneration and recovery is complex, and the current monitoring strategies can have difficulty controlling the interlocking chemical equilibria. A complimentary tool, thin-film UV-Vis spectroscopy, can be utilized to improve the current monitoring strategies, as UV-Vis is capable of identifying and predicting etching behavior that the current standard methodologies have difficulty predicting. Furthermore, as a chemically-sensitive probe, UV-Vis can investigate the complex changes to the chemical equilibrium and speciation of the etch bath, and can contribute overall to significant improvements in the control of the copper etching system in order to …
Date: August 2017
Creator: Lambert, Alexander S.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Arduino Based Hybrid MPPT Controller for Wind and Solar (open access)

Arduino Based Hybrid MPPT Controller for Wind and Solar

Renewable power systems are becoming more affordable and provide better options than fossil-fuel generation, for not only the environment, but a benefit of a reduced cost of operation. Methods to optimize charging batteries from renewable technologies is an important subject for off-grid and micro-grids, and is becoming more relevant for larger installations. Overcharging or undercharging the battery can result in failure and reduction of battery life. The Arduino hybrid MPPT controller takes the advantage of solar and wind energy sources by controlling two systems simultaneously. The ability to manage two systems with one controller is better for an overall production of energy, cost, and manageability, at a minor expense of efficiency. The hybrid MPPT uses two synchronous buck DC-DC converters to control both wind and solar. The hybrid MPPT performed at a maximum of 93.6% efficiency, while the individual controller operated at a maximum 97.1% efficiency when working on the bench test. When designing the controller to manage power production from a larger generator, the inductor size was too large due to the frequency provided by the Arduino. A larger inductor means less allowable current to flow before the inductor becomes over saturated, reducing the efficiency of the controller. Utilizing …
Date: December 2017
Creator: Assaad, Michael
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Are Streams Protected? Outcomes of Environmental Regulation (open access)

Are Streams Protected? Outcomes of Environmental Regulation

Urban areas experience the loss of natural stream channels through conversion to artificial conveyances. This process tends to target headwater and other low order streams. The purpose of this study is to determine the patterns of stream loss in Denton, Texas, and explore the regulatory structure that manages these streams. Historic and current maps and stream data are used to map Denton's streams and categorize them according to their vertical connectivity as: 1) "intact", streams that are open to the atmosphere and connect to groundwater; 2) "concrete", channelized streams open to the atmosphere but cut off from groundwater; and 3) "buried", streams disconnected from the atmosphere and groundwater. A review of federal, state, and local regulatory codes and interviews with local government officials and other stakeholders elucidates stream management in Denton. Results from these analyses reveal high rates of stream loss in the urban center with low rates overall. The federal Clean Water Act and the local Environmentally Sensitive Areas code serve as the primary protective measures for natural streams. These regulations discourage stream impacts through expensive and complex permitting requirements. However the policies allow minor impacts which may cause cumulative effects. This study aims to inform future policy-making decisions …
Date: August 2017
Creator: Rowen, Zachary
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Artscapes: Community Perceptions of City Beautification through Murals in Denton, Texas (open access)

Artscapes: Community Perceptions of City Beautification through Murals in Denton, Texas

Keep Denton Beautiful (KDB) is inspired by Keep America Beautiful's model of community engagement to create a clean, beautiful, and vibrant city. The community mural initiative, Artscapes, aims to enliven public spaces, abate graffiti, and inspire community members to keep Denton, Texas, clean and beautiful. The goals of this research project are to understand the impact of Artscapes initiative, community perceptions of public art, and find ways KDB can better align future mural projects with the needs and desires of community members. By talking to artists that have worked with KDB, members of the mural art committee, and community members from the neighborhoods that have existing murals, this research provides input from these three populations to continue creating public art for the Denton community. I discuss the context of my work through Lefebvre's concept of "Right to the City," Rafael Schacter's opposition between sanctioned and non-sanctioned murals, Bourdieu's concept of symbolic and social capital, and David Harvey's work on neoliberalism and the entrepreneurial city.
Date: December 2017
Creator: Robertson, Lindsey
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Assessing Rainfall Interception by Urban Tree Canopies in Denton, Texas (open access)

Assessing Rainfall Interception by Urban Tree Canopies in Denton, Texas

Rainfall interception is one mechanism by which tree canopies can reduce surface runoff in urban areas. The objectives of this research were to: 1) quantify rainfall interception by urban tree canopies, and 2) determine the influence of vegetation and microenvironmental factors on rainfall interception rates. In the city of Denton, Texas, 30 mature post oak (Quercus stellata) and blackjack oak (Quercus marilandica) trees were selected for study. Trees were assigned to one of three categories: clusters of trees on greenspace (CG), isolated trees on greenspace (IG), and isolated trees surrounded by pavement (IP). Throughfall (the volume of water that travels through the canopy and reaches the soil surface) collectors were placed beneath these trees and rainfall collectors were placed in nearby open areas. Throughfall and rainfall were collected daily from 19 March to 4 July. Interception was calculated as the difference between throughfall and gross rainfall. Over the study period, there were 27 days with measurable rainfall; daily rainfall ranged from 1-51 mm. Over the sampling period, rainfall interception for individual trees ranged from -10% to 49%, indicating high spatial variability in interception. Percent interception was highest for the CG treatment (22.7 ± 3.8 SE), intermediate for IG (27.4 ± …
Date: May 2017
Creator: Edington, Patrick
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Automated GUI Tests Generation for Android Apps Using Q-learning (open access)

Automated GUI Tests Generation for Android Apps Using Q-learning

Mobile applications are growing in popularity and pose new problems in the area of software testing. In particular, mobile applications heavily depend upon user interactions and a dynamically changing environment of system events. In this thesis, we focus on user-driven events and use Q-learning, a reinforcement machine learning algorithm, to generate tests for Android applications under test (AUT). We implement a framework that automates the generation of GUI test cases by using our Q-learning approach and compare it to a uniform random (UR) implementation. A novel feature of our approach is that we generate user-driven event sequences through the GUI, without the source code or the model of the AUT. Hence, considerable amount of cost and time are saved by avoiding the need for model generation for generating the tests. Our results show that the systematic path exploration used by Q-learning results in higher average code coverage in comparison to the uniform random approach.
Date: May 2017
Creator: Koppula, Sreedevi
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Baby Trap

Work of art in Sterling Silver by artist Keela Dooley part of a 2019 MFA Exhibition, entitled "Trappings"
Date: 2017
Creator: Dooley, Keela Dee
Object Type: Artwork
System: The UNT Digital Library

Barracoon 2018

Work of art in branches, cotton thread screws, and rope by artist Taylor Barnes as part of a 2019 MFA Exhibition, entitled "Who's Next?"
Date: 2017
Creator: Barnes, Taylor
Object Type: Artwork
System: The UNT Digital Library
Best Practices in Targeted Advertising for Fashion Entrepreneurs (open access)

Best Practices in Targeted Advertising for Fashion Entrepreneurs

A key to a business's success is reaching the target market. This ensures that consumers are exposed to the retailer's offerings and by turn, inspired to purchase. In turn, the business can reach its goal of a profitable organization. The purpose of this paper was to determine the most effective fashion advertising appeals for reaching target markets. To address these issues, this thesis consisted of two studies. The purpose of the first study was to determine the advice given to fashion entrepreneurs regarding effective target market practices. The purpose of the second study was to determine effective advertising strategies fashion entrepreneurs may employ for effectively reaching target markets. Data was collected to test the effectiveness of the advice from Study 1, degrees of brand awareness, attitudes towards advertising, willingness to follow trends, purchase intention, purchase behavior, and shopping involvement. The Theory of Reasoned Action was employed as the theoretical framework of the study. The framework was utilized to predict that attitudes towards targeted advertising and pressure to follow fashion trends would positively relate to intent to purchase which, in turn, would positively relate to purchase behavior. The results of this paper concluded the TRA model provided a proper framework to …
Date: August 2017
Creator: Slaton, Kelcie Shaelyn
Object Type: Thesis or Dissertation
System: The UNT Digital Library
BLE Controller Module for Wireless Sensor Networks (open access)

BLE Controller Module for Wireless Sensor Networks

Sensors have been an integral part of our life since a long time. Traditionally, the transmit information to a data collection center through a physical wire. However, with the introduction of Bluetooth Low Energy (BLE) communication protocol, more research is being done into the field of wireless sensor networks (WSN). BLE was introduced to target low power applications. The CC2650 Launchpad designed by Texas Instruments (TI) can lead to a bulky final product. The aim was to design hardware for the CC2650 micro-controller with the aim of making it more compact for use in WSNs. A top-down approach was used wherein the available product is studied to identify the redundant and reverse engineer it to design a new product. A 2 layer printed circuit board (PCB) was designed which resulted in a 64 percent decrease in size compared to the Launchpad. Also, experiments were performed to test the proof of concept.
Date: August 2017
Creator: Vaswani, Mohit Suresh
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Blue is my Favorite Color

Work of art in cotton fabric, polyester thread (Photo by Megan Desoto) by artist Alyssa Russell as part of a 2019 MFA Exhibition, entitled "On/Scenity".
Date: 2017
Creator: Russell, Alyssa
Object Type: Artwork
System: The UNT Digital Library
Bodies of Evidence: A Qualitative Analysis of the Lived Experiences of Female Central American and Mexican Asylum Seekers in Dallas (open access)

Bodies of Evidence: A Qualitative Analysis of the Lived Experiences of Female Central American and Mexican Asylum Seekers in Dallas

This work addresses the experiences of female asylum seekers from Central and Mexico currently living in Dallas, TX. The main purpose is to analyze how these women engage in the gendered processes of both migrating to and accessing legal resources and protection within the United States. As the women move through male-dominated spaces in their home country, the borderlands, and the asylum court they must challenge the patriarchal institutions that attempt to silence their narratives and criminalize their bodies. Their physical wounds become evidence in the courtroom, while outside of the courtroom their movements are monitored and tracked through multiple mechanisms of state control: ankle monitors, detention centers, ICE check-ins. They face intersectional discrimination as they are targeted as both women and immigrants. However, these female asylum seekers are not victims. They constantly display agency as they represent themselves in court, find solace in their faith, and form community with each other.
Date: May 2017
Creator: Kober, Ryan K.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

I Bought Three

Work of art in cotton fabric, polyester thread (Photo by Megan Desoto) by artist Alyssa Russell as part of a 2019 MFA Exhibition, entitled "On/Scenity".
Date: 2017
Creator: Russell, Alyssa
Object Type: Artwork
System: The UNT Digital Library
Brain Computer Interface (BCI) Applications: Privacy Threats and Countermeasures (open access)

Brain Computer Interface (BCI) Applications: Privacy Threats and Countermeasures

In recent years, brain computer interfaces (BCIs) have gained popularity in non-medical domains such as the gaming, entertainment, personal health, and marketing industries. A growing number of companies offer various inexpensive consumer grade BCIs and some of these companies have recently introduced the concept of BCI "App stores" in order to facilitate the expansion of BCI applications and provide software development kits (SDKs) for other developers to create new applications for their devices. The BCI applications access to users' unique brainwave signals, which consequently allows them to make inferences about users' thoughts and mental processes. Since there are no specific standards that govern the development of BCI applications, its users are at the risk of privacy breaches. In this work, we perform first comprehensive analysis of BCI App stores including software development kits (SDKs), application programming interfaces (APIs), and BCI applications w.r.t privacy issues. The goal is to understand the way brainwave signals are handled by BCI applications and what threats to the privacy of users exist. Our findings show that most applications have unrestricted access to users' brainwave signals and can easily extract private information about their users without them even noticing. We discuss potential privacy threats posed by …
Date: May 2017
Creator: Bhalotiya, Anuj Arun
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Cardiovascular Response to a Behavioral Restraint Challenge: Urge Magnitude Influence in Men and Women (open access)

Cardiovascular Response to a Behavioral Restraint Challenge: Urge Magnitude Influence in Men and Women

Agtarap, Wright, Mlynski, Hammad, and Blackledge took an initial step in providing support for the predictive validity of a new conceptual analysis concerned with behavioral restraint, defined as active resistance against a behavioral impulse or urge. The current study was designed to partially replicate and extend findings from their study, employing a common film protocol and a procedure for inducing low- and high levels of fatigue. Analyses on key data indicated that the fatigue manipulation was ineffective. On the other hand, they supported the suggestion that behavioral restraint should be proportional to the strength of an urge being resisted so long as success is perceived as possible and worthwhile. Analyses also provided evidence of gender differences for this behavioral restraint task. Women showed relatively enhanced CV responses to my manipulation of urge magnitude, performed less well, rated the behavioral restraint challenge as harder, and rated success on the more difficult behavioral restraint task as more important. A broad indication is that men and women can differ in the strength of impulses they experience in response to stimulus presentations as well as in the importance they place on resisting the impulses.
Date: May 2017
Creator: Mlynski, Christopher
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Case Studies to Learn Human Mapping Strategies in a Variety of Coarse-Grained Reconfigurable Architectures (open access)

Case Studies to Learn Human Mapping Strategies in a Variety of Coarse-Grained Reconfigurable Architectures

Computer hardware and algorithm design have seen significant progress over the years. It is also seen that there are several domains in which humans are more efficient than computers. For example in image recognition, image tagging, natural language understanding and processing, humans often find complicated algorithms quite easy to grasp. This thesis presents the different case studies to learn human mapping strategy to solve the mapping problem in the area of coarse-grained reconfigurable architectures (CGRAs). To achieve optimum level performance and consume less energy in CGRAs, place and route problem has always been a major concern. Making use of human characteristics can be helpful in problems as such, through pattern recognition and experience. Therefore to conduct the case studies a computer mapping game called UNTANGLED was analyzed as a medium to convey insights of human mapping strategies in a variety of architectures. The purpose of this research was to learn from humans so that we can come up with better algorithms to outperform the existing algorithms. We observed how human strategies vary as we present them with different architectures, different architectures with constraints, different visualization as well as how the quality of solution changes with experience. In this work all …
Date: May 2017
Creator: Malla, Tika K.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Catalytic Properties and Mechanical Behavior of Metallic Glass Powders (open access)

Catalytic Properties and Mechanical Behavior of Metallic Glass Powders

Lack of crystalline order and microstructural features such as grain/grain-boundary in metallic glasses results in a suite of remarkable attributes including very high strength, close to theoretical elasticity, high corrosion and wear resistance, and soft magnetic properties. By altering the morphology and tuning of composition, MGs may be transformed into high-performance catalytic materials. In this study, the catalytic properties of metallic glass powders were demonstrated in dissociating toxic organic chemicals such as AZO dye. BMG powders showed superior performance compared to state of the art crystalline iron because of their high catalytic activity, durability, and reusability. To enhance the catalytic properties, high energy mechanical milling was performed to increase the surface area and defect density. Iron-based bulk metallic glass (BMG) of composition Fe48Cr15Mo14Y2C15B6 was used because of its low cost and ability to make large surface area by high energy ball milling. AZO dye was degraded in less than 20 minutes for the 9 hours milled Fe-BMG. However, subsequent increase in ball milling time resulted in devitrification and loss of catalytic activity as measured using UV-Visible spectroscopy. Aluminum-based bulk metallic glass (Al-BMG) powder of composition Al82Fe3Ni8Y7 was synthesized by arc-melting the constituent elements followed by gas-atomization. The particle size and …
Date: May 2017
Creator: Garrison, Seth
Object Type: Thesis or Dissertation
System: The UNT Digital Library

The Catch

Work of art in Sterling Silver & Steel by artist Keela Dooley part of a 2019 MFA Exhibition, entitled "Trappings"
Date: 2017
Creator: Dooley, Keela Dee
Object Type: Artwork
System: The UNT Digital Library