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Cold-Formed Steel Member Connections Using BAC Screw Fasteners

Access: Use of this item is restricted to the UNT Community
In this project, the main research objective is intend to seek criteria for evaluating the capacity of BAC screw fasteners with mixed configuration of waterproof seal washer, sealer tape and different pre-drill holes to determine shear and tension strength values for the screws used in cold-formed steel connections. The thesis presents the design methods and test program conducted to investigate the behavior and strength of the screw connections in shear and tension test. Test results were compared with AISI design provisions to determine if new design equations will be developed for those screws used in BAC cooling tower applications. LRFD resistance factors and ASD safety factors were investigated to the proposed design equations.
Date: May 2019
Creator: Li, Xun
System: The UNT Digital Library

CFD Study of Ship Hydrodynamics in Calm Water with Shear Current and in Designed Wave Trails

Although the capability of computational fluid dynamics (CFD) in modeling ship hydrodynamics is well explored in many studies, they still have two main limitations. First, those studies ignore the effect of non-uniform shear current which exists in realistic situation. Second, the focus of most studies was laid more on the seakeeping/maneuvering performance and less attention was paid to survivability of ships due to extreme ship response events in waves, which are considered rare events but influential. In this thesis, we explore the capability of CFD in those two areas. In the first part of the thesis, the hydrodynamic performance of KCS in the presence of a non-uniform shear current is investigated for the first time using high-fidelity CFD simulations. Various shear current conditions with different directions were considered and results were compared with the ones with no shear current. The second part of the thesis focuses on study of rare events of ship responses by development of extreme response conditioning techniques to design the wave trail. Two conditioned techniques based on Gaussian and non-Gaussian processes are considered.
Date: May 2022
Creator: Phan, Khang Minh
System: The UNT Digital Library
Impact of Processing Parameters and Forces on Channels Created by Friction Stir Bobbin Tools (open access)

Impact of Processing Parameters and Forces on Channels Created by Friction Stir Bobbin Tools

In this thesis, friction stir channeling (FSC) and its process parameters influence on geometry, surface quality and productivity are explored. The probe of the friction stir processing (FSP) tool used to perform these tests was a modified submerged bobbin tool made of MP 159 Co-Ni alloy. The body was made from H13 tool steel. To find the optimal channel conditions for a targeted range of process parameters, multiple 6061 aluminum samples were prepared with a U shape guide to test the effects of different spindle speeds and feed rates. Using a gantry-type computer numerical control (CNC) friction stir welding (FSW) machine, the aluminum coupons were subjected to calibration experiments, force control tests, and an increased production rate to test these effects. It was found through experimentation that the programmed feed rates, spindle speeds and forces produced by the machine had an impact on the channel geometry. It was determined from the force-controlled setup that 8.46 mm/s at 750 RPM was the best combination of results for the four conditions tested on a CNC friction stir processing-machine. It was then tested at 10.58 mm/s at 800 RPM, which had comparable results with the best combination of input parameters from the force-controlled …
Date: May 2022
Creator: Koonce, James G
System: The UNT Digital Library
Topology and Lattice-Based Structural Design Optimization for Additively Manufactured Medical Implants (open access)

Topology and Lattice-Based Structural Design Optimization for Additively Manufactured Medical Implants

Topology-based optimization techniques and lattice structures are powerful ways to accomplish lightweight components with enhanced mechanical performance. Recent developments in additive manufacturing (AM) have led the way to extraordinary opportunities in realizing complex designs that are derived from topology and lattice-based structural optimization. The main aim of this work is to give a contribution, in the integration between structural optimization techniques and AM, by proposing a setup of a proper methodology for rapid development of optimized medical implants addressing oseeointegration and minimization of stress shielding related problems. The validity of the proposed methodology for a proof of concept was demonstrated in two real-world case studies: a tibia intramedullary implant and a shoulder hemi prosthetics for two bone cancer patients. The optimization was achieved using topology optimization and replacement of solid volumes by lattice structures. Samples of three lattice unit cell configurations were designed, fabricated, mechanically tested, and compared to select the most proper configuration for the shoulder hemi prosthesis. Weight reductions of 30% and 15% were achieved from the optimization of the initial design of the tibia intramedullary implant and the shoulder hemiprosthesis respectively compared to initial designs. Prototypes were fabricated using selective laser melting (SLM) and direct light processing …
Date: May 2019
Creator: Peto, Marinela
System: The UNT Digital Library
Public Research Universities as Gendered Organizations: Institutional Rewards and the Faculty Salary Gap (open access)

Public Research Universities as Gendered Organizations: Institutional Rewards and the Faculty Salary Gap

Gendered organizational conditions create the context for persisting differences between men and women in the workplace. Within, higher education, this manifests as a salary gap between male and female faculty members. The academic capitalistic policy environment creates the conditions for increasing competition for external funding, especially in the areas of research and science and engineering. The change in the academic climate may sustain or intensify the gendering of universities as organizations. Universities with the highest level of research activity were chosen for this study and formed the 130 public institution sample. This study used fixed effects panel regression analysis to explore the relationship between the faculty gender salary gap and institutional emphasis on research as well as science and engineering. In addition, the relationship between institutional emphasis and the faculty gender salary gap was explored over time with the inclusion of a time trend and temporal interaction terms. Results showed that the higher the percentage of female faculty members, the greater the faculty gender salary gap for assistant professors. In addition, science and engineering emphasis over time had a significant impact on the professor salary gap with a decreasing effect both at the mean and one standard deviation above the …
Date: May 2017
Creator: Johnson, Jessica Ann (Higher education researcher)
System: The UNT Digital Library

Some Names for Empty Space

Some Names for Empty Space is a collection of poems that considers how poetry and language operate to define human experience, reconciling the 'empty spaces' between the self and the abstracted variables of all things. The poems here often find their impetus in fatherhood and a parent's efforts to explain the world to a child.
Date: May 2021
Creator: Koch, Andrew (Poet)
System: The UNT Digital Library
Extracting Possessions and Their Attributes (open access)

Extracting Possessions and Their Attributes

Possession is an asymmetric semantic relation between two entities, where one entity (the possessee) belongs to the other entity (the possessor). Automatically extracting possessions are useful in identifying skills, recommender systems and in natural language understanding. Possessions can be found in different communication modalities including text, images, videos, and audios. In this dissertation, I elaborate on the techniques I used to extract possessions. I begin with extracting possessions at the sentence level including the type and temporal anchors. Then, I extract the duration of possession and co-possessions (if multiple possessors possess the same entity). Next, I extract possessions from an entire Wikipedia article capturing the change of possessors over time. I extract possessions from social media including both text and images. Finally, I also present dense annotations generating possession timelines. I present separate datasets, detailed corpus analysis, and machine learning models for each task described above.
Date: May 2020
Creator: Chinnappa, Dhivya Infant
System: The UNT Digital Library
Smartphones and Tablets: Patterns of Usage among College Student Populations (open access)

Smartphones and Tablets: Patterns of Usage among College Student Populations

This study offers insight into students' use and desire to use mobile devices for educational purposes. I examined college students' mobile device usage on the basis of demographic factors including sex, age, ethnicity, class standing, mode of delivery, and socioeconomic status. This study also investigated factors that affect students' likelihood to use mobile devices for academic pursuits. I utilized data from the EDUCAUSE Center for Analysis and Research's (ECAR) 2015 Student Technology Survey. Of the 10,000 undergraduate respondents, 56% were female, 70% were between the ages of 18-24, 73% attended college full time and the breakdown of ethnicity included 59% Caucasian, 16% Hispanic, 13% African American, 8% Asian and 1% Native American. The results indicated that traditional aged students reportedly used smartphones more frequently, whereas non-traditional aged students reportedly used tablets more. Students most frequently reported using their devices in class to connect to the learning material. Institutional technology infrastructure and support were strong factors impacting students' use of smartphones. Results of this research can assist higher education faculty and administrators in devising comprehensive training and technology plans to support and encourage students' use of mobile devices for educational purposes.
Date: May 2017
Creator: Phillips, Ann (Higher education researcher)
System: The UNT Digital Library
The Product is People: An Investigation of Missile Combat Crew Perceptions Surrounding Standardized Training Curriculum (open access)

The Product is People: An Investigation of Missile Combat Crew Perceptions Surrounding Standardized Training Curriculum

Missile Combat Crew members are officers in the United States Air Force responsible for operating nuclear-tipped intercontinental ballistic missiles. They undergo on-the-job training as part of the curriculum necessary to progress in their careers and achieve higher levels of job responsibility. The curriculum they use is created and maintained by 20th Air Force Test and Training Section. This product is known as the Missile Combat Crew Commander Upgrade program, and it has received criticisms from stakeholders who use it for being out of date and failing to capture the necessary topics for ensuring adequate on the job training is being conducted. This project seeks to examine these critiques, break down the curriculum produced by 20th AF into stages (creation, implementation, and feedback) for evaluation, uses principles of user-oriented design drawing on design anthropology to suggest alternative methods for curriculum creation, and utilizes the results of a diagnostic survey to provide data-driven recommendations to 20th AF for future rewrites of their product based on feedback from the crew members who use their product in the field.
Date: May 2023
Creator: Hanel, Daniel James
System: The UNT Digital Library
Nothing Short of Really Healthy Children: Mothers, the Children's Bureau, and Disability, 1914 - 1933 (open access)

Nothing Short of Really Healthy Children: Mothers, the Children's Bureau, and Disability, 1914 - 1933

In 1931 the United States Children's Bureau asserted that "nothing short of really healthy children should satisfy parents." This thesis examines how literature published by the Children's Bureau from 1913 to 1933 shaped perceptions of motherhood and of maternal control over the body. As the bureau taught mothers how to care for their children, it also taught them that by following bureau advice, mothers could shape the bodies of their children to adhere to normative body standards. The research considers the relationship between mothers, the state, and the physical body. This thesis is divided into chapters about prenatal care and maternal marking; infant care and maternal policing; and child care and maternal control.
Date: May 2023
Creator: Edsall, Brooke C.
System: The UNT Digital Library
Analysis of "The Seven Songs" From The Pilgrim's Progress By Ralph Vaughan Williams (open access)

Analysis of "The Seven Songs" From The Pilgrim's Progress By Ralph Vaughan Williams

The opera, The Pilgrim's Progress, was written by Ralph Vaughan Williams in 1949. "The Seven Songs" are analyzed for performance, examining the elements of music and text of the songs, including melody, harmony, form, vocal line and accompaniment, with the intent of forming conclusions in regard to their usefulness as singular selections, or as a group, for performance.
Date: May 1968
Creator: Hindman, Jannette
System: The UNT Digital Library
Discriminative Control of Behavioral Variability in Video Game Play (open access)

Discriminative Control of Behavioral Variability in Video Game Play

Creativity can be a useful skill in today's classrooms and workplaces. When individuals talk about creativity, it's unclear what the controlling variables are when we tact behavior as "creative." Research in understanding the processes behind behaviors that are considered "creative" would assist in identifying functional relations and provide insight on how to teach creativity. Since creativity is often described as doing something different from the norm, behavioral variability may be a potential aspect of creativity. This study aimed to replicate previous findings by investigating the effects of discrimination training in a multiple schedule of varied and repetitive responding in the context of a video game. Participants played through a 2D online video game made in Bloxels. Different alternating-colored platforms served as the discriminative stimuli for the vary and repeat components. Three parameters of variability were measured (e.g., left jumps, right jumps, and double jumps). The results of the study indicate that participants were able to learn the discrimination of when to repeat and vary their responses depending on which colored platform they encountered.
Date: May 2023
Creator: Arias, Gabriela Isabel
System: The UNT Digital Library
Grand Canyons: Authoritative Knowledge and Patient-Provider Connection (open access)

Grand Canyons: Authoritative Knowledge and Patient-Provider Connection

In 2011, African Americans in Tarrant County, Texas experienced an infant mortality rate of 14.3 per 1,000 live births. The leading cause of infant mortality in Tarrant County is prematurity and maternal nutritional status. Both maternal under-nutrition and over-nutrition are known risk factors for premature birth. Improving maternal nutrition, by reducing rates of gestational diabetes and preeclampsia, and by increasing consumption of essential prenatal vitamins and nutrients, is a road to decreasing preterm birth in African Americans. This qualitative study, based on both anthropology and public health theory, of the nutrition behavior of a group of African American expectant mothers and the experience of their health care providers and co-facilitators had a goal to provide a foundation for future development of nutrition behavior research and education for this specific population. The main finding of this study was the substantial gap of lived experience and education between the patients and their providers and co-facilitators, which hinders delivery of care and the patients’ acquiescence to nutrition recommendations. The discrepancies between the authoritative knowledge of the providers and the bodily knowledge of expectant mothers were responsible for the ineffectiveness of nutrition recommendations.
Date: May 2015
Creator: Fowler, Rebecca (Public health researcher)
System: The UNT Digital Library
Multicultural Training and Program Climate in Masters Sport Psychology Programs (open access)

Multicultural Training and Program Climate in Masters Sport Psychology Programs

Little is known about the current state of multicultural training within sport psychology master's programs. The study explored students' perceptions of their multicultural training and program climate. Importantly, differences in perceptions were investigated based on students' demographic factors, given that students with marginalized identities tend to report less favorable perceptions of and experiences in graduate training. Participants (N = 107) consisted of students and recent graduates of master's level sport psychology programs. Participants reported moderate levels of feeling safe, valued, and comfortable within their master's program, low to moderate levels of multicultural training integration within their curriculum and supervision, and low to moderate satisfaction with their multicultural training. Asian, Asian American, bi/multiracial, Black, African American, Hispanic, and Latino/a/e students, compared to their White peers, reported less satisfaction with their multicultural training, felt less safe, comfortable, and valued within their programs, and perceived less integration of multiculturalism into curriculum and supervision. A multiple regression analysis revealed that, for all students, perceptions of multicultural training integration and reports of feeling safe, comfortable, and valued was significantly related to students' satisfaction with their multicultural training. Discussion focuses on possible explanations for these findings, training implications, and future research directions.
Date: May 2023
Creator: Arnold, Macey L.
System: The UNT Digital Library
"Scent of Ink": A Study and Performance Guide of Selected Gagok by Wonju Lee (open access)

"Scent of Ink": A Study and Performance Guide of Selected Gagok by Wonju Lee

Wonju Lee (b. 1979) has already made her own unique contribution to Korean art song. Her songs commissioned by classical Korean music performers have been recorded and released on record labels such as Universal Music and Sony Music. Albums include the Gagok collection, Lee Hwa-woo, The Pear Blossom Falls published by Soo Moon Dang. Some songs have been published by music publishers in the United States such as Classical Vocal Reprints and in Korea by the Korean Traditional Music Resource Center. Wonju Lee's songs are being performed by singers not only in Korea but also in the United States. This study provides information regarding the history of Gagok (Korean art songs) and discusses two duets "Scent of Ink" and "Under the Cherry Tree," and three solo songs "Sam-Arirang," "Relationship," and "Loom Song" by Wonju Lee. This critical essay includes biographical information about the composer and poets, IPA transcriptions for each song, and both word-for-word and poetic translations. In addition, using the methodology from Carol Kimball's book Song: A Guide to Art Song Style and Literature, style sheets of musical characteristics for each song and for the composer are provided and serve as the basis for interpretive recommendations for performers.
Date: May 2022
Creator: Lee, Eun Kyung
System: The UNT Digital Library