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3D Printing of Zinc Anode for Zinc Ion Batteries

Recently, 3D printing has received increasing attention for the fabrication and assembly of electrodes for batteries due to the freedom of creating structures in any shape or size, porosity, flexibility, stretchability, and chemistry. Particularly, zinc ion batteries (ZIBs) are favored due to high safety, cheap materials cost, and high volumetric capacity (5,849 mAh/cm3), however, rapid evaporation of Zn due to low melting temperature has limited its 3D printability via conventional laser-based additive manufacturing technique. Here, we develop a printable ink for the fabrication of flexible and 3D printed Zn anode with varied surface areas using the direct ink writing (DIW) method. Our 3D printed porous and high surface area Zn anode structures effectively suppressed the dendrite growth while providing high Zn ion diffusion towards the cathode to significantly enhance the performance of ZIB. By varying filament distancing and path, we 3D printed zinc anode structures with different active surface areas, surface area to volume ratio, porosity, flexible and multiple layer structures that can be incorporated on any device. Carbon in the composite improved conductivity, and mechanical stability of 3D printed zinc anode. Our 3D printed composite anodes allowed flexible designing of batteries surpassing conventional battery designs such as coin cells …
Date: December 2021
Creator: Amoko, Stephen Adot Oyo
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Additive Manufacturing of AZ31B Magnesium Alloy via Friction Stir Deposition (open access)

Additive Manufacturing of AZ31B Magnesium Alloy via Friction Stir Deposition

Additive friction stir deposition (AFSD) of AZ31B magnesium alloy was conducted to examine evolution of grain structure, phases, and crystallographic texture. AFSD was carried out using a hollow tool made from tool steel at a constant rotational velocity of 400 rpm on the AZ31B base plate. Bar stock of AZ31B was utilized as a feed material. The linear velocity of the tool was varied in the range of 4.2-6.3 mm/s. The feed rate of the material had to be maintained at a half value compared to the corresponding linear velocity for the successful deposition. The layer thickness and length of the deposits were kept constant at 1 mm and 50 mm respectively. The tool torque and actuator force values were recorded during the process and for calculation of the average input energy for each processing condition. Temperature during the AFSD experiments was monitored using a type k thermocouple located 4 mm beneath the deposition surface at the center of the deposition track. The average input energy values showed a decreasing trend with increasing tool linear velocity. The temperature values during deposition were ∼0.7 times the liquidus of the alloy. The deposited material then was examined by laser microscope and profilometer, …
Date: December 2021
Creator: Patil, Shreyash Manojkumar
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Adoption of Credit-Hour Reductions in Master of Divinity Programs at the Association of Theological Schools Member Institutions: An Event History Analysis (open access)

Adoption of Credit-Hour Reductions in Master of Divinity Programs at the Association of Theological Schools Member Institutions: An Event History Analysis

Seminaries in the United States have for more than two centuries sought to equip ministerial leaders for service within the community of faith. And yet these institutions have traditionally been the focus of very little quantitative research. This lack of data is particularly noteworthy given the existential crises many seminaries currently face, especially regarding their flagship Master of Divinity (MDiv) programs. Among seminary leadership, a common response to declining MDiv enrollment has been to decrease the length of the program, which historically required at least 90 credit hours. The purpose of this quantitative study was to explore change at the Association of Theological Schools member institutions (AMIs) between 2000–2019 through the lens of these credit-hour reductions. Longitudinal data from 113 AMIs were analyzed to examine the relationship between a variety of financial, enrollment, and institutional characteristics and the likelihood that an AMI would reduce its required MDiv credit hours. Results from an event history analysis revealed that, all else being equal, experiencing an increase in total revenues reduced an AMI's likelihood of making a reduction, while being a middle-age institution (founded 1870–1959) and having a higher percentage of peer institutions that made a change increased the likelihood of making a …
Date: December 2021
Creator: McKanna, Nathan Jay
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Advanced Cathodes for High Energy Density Lithium Sulfur Battery

A systematic development of 2D alloy catalyst with synergistic performance of high lithium polysulfide (LiPS) binding energy and efficient Li+ ion/electron conduction is presented. The first section of work found that Li+ ions can flow through the percolated ion transport pathway in polycrystalline MoS2, while Na+ and K+ ions can easily flow through the percolated 1D ion channel near the grain boundaries. An unusually high ionic conductivity of extrinsic Li+, Na+, and K+ ions in 2D MoS2 film exceeding 1 S/cm was measured that is more than two orders of magnitude higher than those of conventional solid ionic materials, including 2D ionic materials. The second section of this dissertation focus on catalyzing the transformation of LiPSs to prevent the shuttle effect during the battery cycling by synthesizing 2H (semiconducting) – 1T (metallic) mixed phase 2D Mo0.5W0.5S2 alloy on CNF paper, using two step sputtering and sulfurization method. The lithium sulfur (Li-S) battery cell assembled with the 2D Mo0.5W0.5S2/CNF/S cathode shows a high specific capacity of 1228 mAh g-1 at 0.1C and much higher cyclic stability over 4 times as compared to the pristine cathodes. The high LiPSs binding energy of catalyst efficiently prevents the shuttling effect and corrosion of Li …
Date: December 2021
Creator: Bhoyate, Sanket
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Aerodynamic Optimization of a 2D Airfoil for Rotary-Wing Aircraft at Mars Atmospheric Conditions

The interest toward Mars exploration has been considerably increasing due to also the successful deployment of the Perseverance rover and the continuous tests developed by SpaceX's launch vehicle, Starship. While the Mars 2020 mission is currently in progress, the first controlled flight on another planet have been proven in April 2021 with the vertical take-off and landing of the Ingenuity rotorcraft on Mars. In addition, the rotorcraft Dragonfly is expected to achieve the same endeavor in Titan, the largest moon of Saturn, by 2036. Continuous efforts have been oriented toward the development of new technologies and aircraft configurations to improve the performance of current proposed designs to achieve powered flight in different planetary bodies. This thesis work is a preliminary study to develop a comprehensive analysis over the generation of optimum airfoil geometries to achieve vertical flight in environments where low Reynolds numbers and Mach number equal to 0.2 and 0.5.
Date: December 2021
Creator: Saez, Aleandro G.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Aging Texas Well Strategic Plan: 2022 - 2023 (open access)

Aging Texas Well Strategic Plan: 2022 - 2023

Strategic plan for the Aging Texas Well program outlining priorities and strategies for addressing them. The goal of the plan is to help older Texans and their informal caregivers plan for the future while providing community and state leadership with recommendations and guidance for establishing policies and the infrastructure to support healthy aging for all Texans.
Date: December 2021
Creator: Texas Health and Human Services Commission
Object Type: Report
System: The Portal to Texas History
Air Corridors: Concept, Design, Simulation, and Rules of Engagement (open access)

Air Corridors: Concept, Design, Simulation, and Rules of Engagement

Air corridors are an integral part of the advanced air mobility infrastructure. They are the virtual highways in the sky for transportation of people and cargo in the controlled airspace at an altitude of around 1000 ft. to 2000 ft. above the ground level. This paper presents fundamental insights into the design of air corridors with high operational efficiency as well as zero collisions. It begins with the definitions of air cube, skylane or track, intersection, vertiport, gate, and air corridor. Then, a multi-layered air corridor model is proposed. Traffic at intersections is analyzed in detail with examples of vehicles turning in different directions. The concept of capacity of an air corridor is introduced along with the nature of distribution of locations of vehicles in the air corridor and collision probability inside the corridor are discussed. Finally, the results of simulations of traffic flows are presented.
Date: December 2021
Creator: Muna, Sabrina Islam
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Algebraic Trait for Structurally Balanced Property of Node and Its Applications in System Behaviors

This thesis targets at providing an algebraic method to indicate network behaviors. Furthermore, for a signed-average consensus problem of the system behaviors, event-triggering signed-average algorithms are designed to reduce the communication overheads. In Chapter 1, the background is introduced, and the problem is formulated. In Chapter 2, notations and basics of graph theory are presented. It is known that the terminal value of the system state is determined by the initial state, left eigenvector and right eigenvector associated with zero eigenvalue of the Laplacian matrix. Since there is no mathematical expression of right eigenvector, in Chapter 3, mathematical expression of right eigenvector is given. In Chapter 4, algebraic trait for structurally balanced property of a node is proposed. In Chapter 5, a method for characterization of collective behaviors under directed signed networks is developed. In Chapter 6, dynamic event-triggering signed-average algorithms are proposed and proved for the purpose of relieving the communication burden between agents. Chapter 7 summarizes the thesis and gives future directions.
Date: December 2021
Creator: Du, Wen (Electrical engineering researcher)
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Analysis of the Integration of LEO Satellite Constellations into 5G Networks

Low Earth orbit (LEO) satellite systems have been proposed as a resource for combating the challenges in 5G network coverage and expanding connectivity to a global realm. This research focuses on the current architecture of LEO satellite constellations, with an emphasis on satellite coverage, visibility patterns and coordination schemes. Key-elements of integrating LEO satellites into the eMBB component of 5G are presented and a breakdown of potential link channel characteristics and physical layer performance metrics are described. The produced information allows for a justified analysis on the conceptualized integration.
Date: December 2021
Creator: Cruz Vazquez, Martin
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Analyzing the Principal Perspective to Lead the Implementation of Learning Technologies in Public Schools: A Multi-Strategy Study (open access)

Analyzing the Principal Perspective to Lead the Implementation of Learning Technologies in Public Schools: A Multi-Strategy Study

As technologies for learning become increasingly available in K-12 schools, the role and responsibilities of campus principals continue to evolve. Incorporating technologies in schools requires shifts in practices, the development of new skills, and in some cases, changes in the mindset of stakeholders. Schools should be capable of absorbing the knowledge and creating the systemic structures required for the implementation ICTs. The purpose of this study was to research the principals' perspective to lead the implementation of ICTs for learning in public schools. As campus leaders, principals are increasingly required to support the utilization of ICTs for classroom instruction. It is of particular importance, therefore, to study and explore the needs school principals identify to lead the implementation of technologies for learning. More specifically, the goal was to gather relevant data to analyze topics that campus principals believe positively and negatively influence the implementation of ICTs in schools.
Date: December 2021
Creator: Orta, Nelson A
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Annual Report on Federal Substance Abuse Prevention and Treatment Block Grant Expenditures: 2020 (open access)

Annual Report on Federal Substance Abuse Prevention and Treatment Block Grant Expenditures: 2020

This report describes all expenditures for programs that received SABG funds during fiscal year 2020 (September 1, 2019 - August 31, 2020). HHSC funds a variety of substance use programs across the substance use service continuum of care. These substance use programs use SABG funds to offer a comprehensive array of prevention, intervention, and treatment services
Date: December 2021
Creator: Texas Health and Human Services Commission
Object Type: Report
System: The Portal to Texas History

Anxiously Yours, (fe)mail: A Narrative Exploration of Anxiety, Empathy and Hope in Art Museum Education

This research explores the relationship between narrative, empathy and anxiety in art museum education. The study begins from my personal experience with anxiety and is methodologically rooted in narrative inquiry and friendship as method. In this study, I propose a creative method of narrative postcard writing called (fe)mail – rooted in a feminist ethic of care that seeks to understand and empathize with the experience of others through correspondence. This research asks relevant questions about the future of art museum programming for mental illness and the act of writing (fe)mail as a reflective practice for academics and educators in the field of social science. In my narrative analysis of the program and the data, I also problematizes my role as researcher, educator and friend throughout the study by considering my own biases, expectations and personal educator agenda. The study is divided into two parts. The first comprises correspondence and analysis of (fe)mail between myself and my best friend/co-participant, Atleigh. In Part I, I conduct a narrative analysis of the (fe)mail data produced between us in order to answer the following questions: What qualities of (fe)mail will appear in the exchange? Can (fe)mail be used as a tool for self-care during …
Date: December 2021
Creator: Galuban, Beatriz Asfora
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Assessing the Clinical Experiences and Attitudes of Play Therapists Working with Children of Parental Substance Use (open access)

Assessing the Clinical Experiences and Attitudes of Play Therapists Working with Children of Parental Substance Use

This study aimed to gain insight into the clinical practices and attitudes of currently practicing play therapists working with children with a parent with a substance use disorder. Participants in the study were play therapists credentialed by the Association for Play Therapy, either as a Registered Play Therapist™ or Registered Play Therapist-Supervisor™. A total of 198 play therapists participated in the study. Results demonstrated that variables including prior education, caseload of children affected by parental substance use, and the number of years since obtaining a mental health licensure explained 16% of the variance in participant attitude scores on the Drug and Drug Problems Perceptions Questionnaire (DDPPQ). Specifically, education (β = -.335, rs2 = .884, p < .001) was found to be a significant predictor of play therapist attitudes towards substance users as it explained 88% of the variance accounted for in the effect. Additionally, although not found to be significant, caseload (β = -.134, rs2 = .325, p = .058) was found to explain 33% of the variance accounted for in the effect. This initial exploration of play therapists' attitudes towards substance users provides strong evidence towards the importance of education and training in substance use disorders. Further exploration of …
Date: December 2021
Creator: Yurkovich, Chelsea V
Object Type: Thesis or Dissertation
System: The UNT Digital Library
A Behavior Analytic Account of Humor Responses: Taking a Joke Way Too Seriously (open access)

A Behavior Analytic Account of Humor Responses: Taking a Joke Way Too Seriously

Compared to other examples of human behavior, humor responses have received relatively little attention from the scientific community and by the behavior analytic community in particular. This study investigated what some of the controlling variables for humans to emit a humor response may be. Participants were randomly presented two types of word sequences/jokes: one with a matching punchline and one without a matching punchline. Participants rated whether the jokes were funny or not funny, and reaction time was measured for all stimuli presented. Generally, the results showed that reaction times to punchlines rated as not funny were shorter than punchlines that were rated funny. These differences in reaction time were interpreted with priming, intraverbal control, and multiple control as an experimental foundation. Limitations include the absence of physiological measures due to COVID-19 restrictions and the forced choice of two rating responses. The implications of this research reveal opportunities for future research of humor responses.
Date: December 2021
Creator: Amezquita IV, Edward Brandon
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Behavioral and Neural Correlates of Speech Perception Outcomes in Adults with Cochlear Implants

Postlingually deafened cochlear implant (CI) adults have large variability in speech perception abilities. While CIs are one of the most successful neural prosthetic devices, they are not able to adequately provide fine structure cues which results in a degraded signal for the listener to interpret. While behavioral measures remain the gold standard for determining speech perception abilities, an objective measure is needed for patients who are unable to provide reliable behavioral responses. Behavioral, cognitive, and neural measures were collected in this study to identify potential neural biomarkers that correlate with speech perception performance. Behavioral experiments evaluated participants' abilities to identify, discriminate, and recognize words as well as sentences in quiet and in noise. Cognitive measures were assessed to determine the roles of attention, impulse control, memory, and cognitive flexibility on speech recognition. Auditory event-related potentials (ERP) were obtained with a double oddball paradigm to produce the mismatch negativity (MMN) response, which has been shown to have associations with phonetic categorical perception at the group level. The results indicated that executive function is highly predictive of speech performance and that the MMN is associated with categorical perception at the individual level. These findings are clinically relevant to determining appropriate follow-up care …
Date: December 2021
Creator: Manning, Jacy
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Behind the Curtain of Public Space: Revealing the Narratives of Corporate Street Hawking in Globalizing Accra

All street hawkers are not the same in many Newly Industrialized Countries (NICs) of the global south as often portrayed by the media and documented in extant literature. This perception has created a gap in knowledge as researchers explore street hawking activities in NICs. In this study, I investigated a new informality trend of street hawking is coming into being within the capital city of Accra, Ghana. As governance is increasingly becoming entrepreneurial, informal activities are gradually becoming formal. Formal and registered businesses are increasingly capitalizing on hawking activities to occupy public spaces. The advent of the informality trend, I term corporate street hawking opens up new issues for the political economy, labor, and urban studies. By employing semi-structured interviews with 47 street hawkers in Accra, this paper sought to investigate three broadly interrelated questions. First, how do neoliberal policies impact the production of public space in Accra? Second, is corporate street hawking a form of creative destruction? Finally, how do corporate street hawkers practice agency within Accra?
Date: December 2021
Creator: Ansah, Hilary Ama
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Body Doubles: Materiality and Gender Non-Binarism in Victorian Supernatural Fiction

This dissertation is a study of supernatural doubles in Victorian literature. It argues that these doubles expand our understanding of gender variance in the Victorian period. The texts in this dissertation privilege gender non-binarism through their depictions of materiality, gender embodiment, and temporality.
Date: December 2021
Creator: Schneider, Katherine
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Brazos Bend State Park: Geoarcheological Assessment and Test Excavations at Site 41FB320, Fort Bend County, Texas (open access)

Brazos Bend State Park: Geoarcheological Assessment and Test Excavations at Site 41FB320, Fort Bend County, Texas

Report detailing geoarchaeological investigations into site 41FB320 at Brazos Bend State Park in Fort Bend County, including an overview of the geology of the site, the cultural findings excavated there, and an assessment of a drainage control program.
Date: December 2021
Creator: Lawrence, Ken; Bury, Benjamin G. & Eyeington, Ashley
Object Type: Report
System: The Portal to Texas History
The Briefing, December 2021 (open access)

The Briefing, December 2021

Newsletter of the Texas Commission on Law Enforcement dsecribing news, events, and activities of the Commission, as well as updates about changes to laws or other information of interest to readers.
Date: December 2021
Creator: Texas Commission on Law Enforcement
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Caesar Kleberg Wildlife Research Institute Report of Current Research: 2021 (open access)

Caesar Kleberg Wildlife Research Institute Report of Current Research: 2021

Annual report of the Caesar Kleberg Wildlife Research Institute discussing the institute's personnel and finances as well as compiled papers summarizing in-progress and completed research, with biographical information about authors and in-press publications.
Date: December 2021
Creator: Caesar Kleberg Wildlife Research Institute
Object Type: Report
System: The Portal to Texas History

A Career Construction Expressive Arts Group: An Exploration of Self-Concept and Life Themes of Preadolescent Girls

Preadolescence is a transitional stage between childhood and adolescence characterized by rapid and erratic change. Preadolescent girls are particularly vulnerable to negative impacts to self-concept and adaptability and may benefit from support to strengthen these key aspects of their development. School-based expressive arts groups provide a developmentally appropriate opportunity for preadolescent girls to process their thoughts, feelings, and experiences that can influence their self-concept and adaptability. Additionally, providing expressive arts groups from a career perspective provides participants a three-fold developmental intervention that includes components of the personal/social, academic, and career domains. Lindo and Ceballos combined the Career Construction Interview (CCI) with expressive arts school-based group counseling to create a developmentally appropriate intervention called the Child and Adolescent Career Construction Interview (CACCI). This study examined preadolescent girls' perceptions of participated in a CACCI group. Analysis of data yielded four major themes: (a) experiencing, (b) connecting, (c) expressing, and (d) becoming. Finding of this study have the potential to inform developmentally appropriate career counseling for preadolescents.
Date: December 2021
Creator: Hastings, Tessa M.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Character Strengths in High School Choir: Students' Perceptions of Their Choral Experience (open access)

Character Strengths in High School Choir: Students' Perceptions of Their Choral Experience

The purpose of this study was to examine the prevalence of character strengths that high school students reported to develop while participating in choir. I created the Character Strengths in Choir Scale (CSCS) to explore the degree to which students believed they exercised 18 character strengths. Local choir students in the pilot study (n = 44) and the main study (n = 114) completed the CSCS and revealed that gratitude, teamwork, and honesty were among the most prevalent strengths while bravery, creativity, and spirituality were among the least prevalent strengths. Student responses were also investigated by subgroups according to gender and years of experience. Results indicated that there were statistically significant differences for the ranking of various character strengths in each subgroup. Aggregately, high school choir students viewed themselves as above average on all assessed strengths.
Date: December 2021
Creator: Critchfield, Jared B., II
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Children With Special Health Care Needs Client Demographics Report: 2021 (open access)

Children With Special Health Care Needs Client Demographics Report: 2021

This report describes the Children with Special Health Care Needs (CSHCN) Services Program’s client demographics yearly by December 1 to the Governor and the Legislative Budget Board. The report include a demographic description of both the population served by the program, and of those individuals on the program's waiting list. Descriptive data includes information regarding income, citizenship, and other health care resources (i.e., insured status).
Date: December 2021
Creator: Texas Health and Human Services Commission
Object Type: Report
System: The Portal to Texas History
The Choral Music of Elaine Hagenberg: From Process to Product to Performance (open access)

The Choral Music of Elaine Hagenberg: From Process to Product to Performance

The Choral Music of Elaine Hagenberg explores the oeuvre of composer Elaine Hagenberg through a musicological, qualitative, and performance-based analysis of her compositional style that has led to her increasing acclaim. This study serves as the first primary source of scholarly output on her. Through an examination of her musical background as a pianist and choral educator, one can identify her principal sources of musical inspiration: text, nature, and her faith. Shaped by these experiences, her compositional philosophy encapsulates five elements of text, form, rhythm, melody, and harmony as she strives to produce singer-centric, authentic, and socially relevant compositions that unite people together. What begins as a consideration of her background and compositional process culminates in practical musical analysis and conducting and vocal considerations to aid future conductors in creating compelling performances of her works. The compositions discussed are As The Rain Hides The Stars (2015), O Love (2016), Song of Miriam (2019), My Companion (2019), and Alleluia (2020).
Date: December 2021
Creator: Cathlina, Francis
Object Type: Thesis or Dissertation
System: The UNT Digital Library