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Investigations Into Selective Laser Melting of Silicon Carbide-Silicon Dioxide Ceramic Composites
Get PDFThis investigative thesis explores the potential of leveraging Selective Laser Melting (SLM) with silicon-based ceramic substrates to form three-dimensional silicon-based glass-ceramic composite parts. A Selective Laser Processing (SLP) machine was developed to conduct experimental research. The machine was utilized to study the effects of silicon dioxide (SiO2) additive in silicon carbide (SiC) substrates as well as the effect of Scanning Energy (SED) on resulting fabricated line widths and fabricated line uniformity. Preliminary and experimental fabricated line width prediction models as functions of SED, substrate SiC content, and scale of SiO2 particulate additive in the substrate were created. The machine was also utilized to study the effects of SED and scanning strategy on defect formation in fabricated square specimens.
It was found that by SLM, melt pool formation and melt pool solidification occurred in substrates containing primarily SiC. Additionally, successful bonding of joints, common in SLM of three-dimensional components, was demonstrated. The exact chemical composition of the final fabricated specimens remained unclear; however, some evidence pointed to the subversion of sublimation of SiC in standard atmosphere under rapid heating and cooling cycles.
The results provide a platform for future investigations in SLM of SiC and can be used as an impetus for increasing efforts to account for and control the process parameters involved. It is expected that with increased experimental, theoretical, and numerical modeling, as well as increased control of process parameters, the fabrication of three-dimensional components by SLM is possible using SiC substrates.It was found that by SLM, melt pool formation and melt pool solidification does occur in substrates containing primarily SiC. also, successful bonding of joints, common in SLM of three-dimensional components, was demonstrated. The exact chemical composition of the final fabricated specimens remains unclear; however, evidence pointed to the subversion of sublimation of SiC in standard atmosphere under rapid heating and cooling cycles.
The results provide a platform for future investigations in SLM of SiC and provide an impetus for increasing efforts to account for and control the process parameters involved. It is expected that with increased experimental, theoretical, and numerical modeling, as well as increased control of process parameters, the fabrication of three-dimensional components by SLM is possible using SiC substrates
Methodus Poetico-Philosophicus
No full textA plausible interpretation of Wittgenstein’s claim that philosophers should be poets can be constructed by drawing together: (1) his conception of the goal of philosophy as the ethical and existential transformation or transvaluation of both the philosopher and the philosophical interlocutor via creative and engagement-inspiring methodological means. (2) His arguments against privacy in language or knowledge of experience and (3) his explication of forms of life and ‘anthropological’ philosophy. The resultant interpretation has radical implications for philosophical methodology and enables the development of space for greater creativity in philosophical authorship and practice
Lesbian, Gay, Bisexual, and Queer (LGBQ) Youth in the Child Welfare System: Hope, Well-Being, and Future Expectations
Get PDFThe purpose of this dissertation is to examine the experiences of an often invisible and understudied population within child welfare, lesbian, gay, bisexual, and queer (LGBQ) youth. Specifically, this research explores support from caregivers, peers, and caseworkers to examine how they influence well-being among LGBQ youth who have been involved in the child welfare system. My analyses use standard statistical methods from a nationally representative data set of youth in the child welfare system and data from the state of Oklahoma. Chapter Two explores how sexual orientation and the quality of the relationship with the youth’s caregiver influences their internalizing and externalizing behavior problems. I find that for LGBQ youth, as the quality of their relationship with their caregiver increases, so too do their reported behavioral problems. I hypothesize why this might be the case. Chapter Three examines the future expectations for LGBQ and non-LGBQ youth, and results showed that caregiver and peer support influence these expectations, in positive and negative ways. Chapter Four looks at LGB youth placed in foster care within the state of Oklahoma and their levels of hope in their child welfare caseworker. My co-authors and I found that LGB youth who have experienced severe adverse childhood experiences (ACES) had greater hope in their caseworker. I conclude by discussing the implications of this research and how policies and programs could be developed, implemented, or improved to help this vulnerable population
Visual and Musical Disability Narratives in How to Train Your Dragon
No full textIn recent decades, the field of disabilities studies has shifted from solely a medical outlook to a more rounded approach of how disability is constructed culturally and socially. With this change, disability scholars aim to understand and accept disability as a part of human experience; establishing a person’s capability and behavior as a difference and not a deficit. Within disability studies, the supposed “deficit” of disability comes from a society deeming someone as normal or abnormal with normalcy as superior to anything that does not meet that standard. Not only can this view of disability studies be reflected on human bodies, but it can also be applied to musical contexts and narrative artforms. As Joseph Straus notes, music and our narratives about it, often allow for metaphors of musical dysfunction and rehabilitation, or of tension and release. Film and film music are two other artforms that also use depictions of disability as obstacles to overcome by the end of the narrative. However, within the field of music theory and disability studies specifically, film soundtracks are a less explored topic. Through this thesis, I seek to provide a cross-disciplinary approach to the analysis of film and music through visual and sonic aspects of disability narratives to provide a better understanding of how these narratives function in society and culture.
In this document I examine four narrative plot points and the accompanying music from the film How to Train Your Dragon (2010) through the lens of disability studies. This animated children’s comedic, adventure, fantasy movie incorporates complex themes of identity and friendship across differences into the narrative and music that creates an enjoyable viewing experience and invites a disability perspective. I will begin with a literary review of the scholarship on music and disability studies and narrative in film. Next, I briefly dive into four plot points that illustrate the underlying normal versus abnormal binary in the film. These plot points center on the outsider status of the main character, Hiccup, and his eventual dragon friend, Toothless, as well as the larger opposition of Hiccup's Viking community and Toothless' dragon family. I analyze important moments within the score that display these binaries, focusing specifically on the relationship between Hiccup and Toothless. To conclude, I discuss the importance of using this lens of disabilities studies to emphasize acceptance, enrich the meaning of music, and provide valuable insight of deeper connections within the narrative of a film and its music. Ultimately, this thesis seeks to expand the interdisciplinary connections across disabilities studies, film studies, and the field of music theory.
Keywords: Music and Disability Studies, Narrative, Film Music, Joseph Straus, Claudia Gorbman, John Powell, How to Train Your Dragon, Children’s Film, Animated Fil
Team Viability’s Outcome-Input Role in Team Effectiveness: A Meta-Analytic Attempt to Disentangle the Confounding Nature of Commonly Used Scales
Get PDFThe purpose of this study is to examine the unique role of team viability within an input-mediator-output-input (IMOI) framework of team effectiveness. Using meta-analytic estimates, I empirically tested the relationships between team viability and major team mediators, namely affective states, behavioral processes, and team cognition, as well as team performance. I also examined how differences in the measurement of team viability moderate these relationships. Results indicate that team viability is most strongly predicted by affective emergent states, followed by behavioral processes and team cognition. Viability is also incrementally predictive of future affective states beyond scores for past affective states but provides the most incremental validity in the prediction of future team cognition beyond scores for past team cognition. However, viability scores do not provide incremental validity in predicting future performance beyond scores for key team mediating variables. The temporal ordering of findings suggests a serial mediation model in which affective states predict viability, viability predicts team cognition, and team cognition is ultimately the strongest proximal predictor of team performance. Results of moderation analyses point to how differences in the measurement of viability confound the meaning of viability’s associations with other constructs in the empirical literature. The content of the viability measure produced meaningful differences in relationships between team viability, the key mediating mechanisms, and team performance, suggesting differences in the content of measures account for important differences in the strength of relationships. Together, these results indicate that viability taps unique variance in team effectiveness suggesting viability has the potential to meaningfully contribute to the team effectiveness literature, though additional refinement is needed for conceptual and measurement clarity
Tropopause Polar Vortex Linkages to Arctic and Midlatitude Phenomena
No full textTropopause polar vortices (TPVs) are coherent, closed tropopause-based vortices that spend at least 60% of their lifetime poleward of 65° latitude. TPVs are identified by a local minima in potential temperature and height, and a local maxima in potential vorticity on the dynamic tropopause. TPVs are most common in the Arctic, where they are often associated with the intensification of Arctic cyclones (ACs), but on occasion exit the Arctic into the midlatitudes where they are often associated with cold air outbreaks (CAOs).
This dissertation investigates TPV linkages to ACs, CAOs, and polar lows (PLs), focusing on systematic TPV-AC linkages and case studies of TPV intensity linkages to an AC case, a PL case, and a major CAO. Rapidly deepening ACs are commonly associated with an upstream TPV which becomes vertically aligned with the AC by the end of the rapid deepening episode. Summer cases are associated with closer proximity to the closest TPV and less lower-tropospheric baroclinic instability than winter cases, with summer cases often over the central Arctic Ocean and winter cases often in the North Atlantic into the Barents and Kara seas. Additionally, ACs whose rapid deepening episode coincides with cyclogenesis are less likely to be over the central Arctic Ocean and are farther from the closest TPV relative to ACs that develop at least 24 h prior to the onset of rapid deepening.
Numerical simulations designed to modify the intensity of two TPVs associated with the August 2012 ``Great Arctic Cyclone" show that stronger TPVs are associated with a faster peak deepening rate and earlier peak intensity of the cyclone, but with the closer TPV to the AC exhibiting a greater impact on the intensification rate of the AC, and the farther TPV exhibiting a greater impact on the track of the AC. The increased intensification rate is primarily associated with stronger differential cyclonic vorticity advection downstream of the TPVs. Weakening the broader upper-tropospheric trough within which the closer TPV is embedded in results in a substantially weaker and more progressive AC. Applying the same TPV modification methodology to an intense PL case only results in very minimal impact on the intensity of the PL, and a 10-member initial condition uncertainty ensemble shows the track and intensity of the PL are more sensitive to the amplitude of a ridge upstream of the TPV than the intensity of the TPV.
Finally, an investigation of the role of two merging TPVs in a historic CAO in the southern Great Plains in February 2021 shows both TPVs had a direct role in the evolution of the CAO, but that backward air parcel trajectories from the southern Great Plains were mostly associated with one TPV instead being distributed equally between both TPVs. The control simulation produces the coldest temperatures at the peak of the CAO in the southern Great Plains, as intensifying both TPVs results in an earlier merger and stronger cold pool but a slower and farther north resultant TPV, while weakening both TPVs results in a weaker cold pool. This result differs from past studies of TPV-CAO linkages where a single, fast-moving TPV exhibited a more direct linkage between TPV intensity and CAO magnitude
INVESTIGATION INTO MANUFACTURING PARTS WITHIN PARTS TO PRODUCE A HIGHER PRESSURE RESILIENT SPHERICAL PRESSURE VESSEL
Get PDFSpecifically, this thesis is an investigation into the use of Additive Manufacturing (AM) for the construction of a small rocket component whose fabrication by means of AM has not been researched extensively. In general, it is an example of how AM can be used to introduce complexity into simple, common parts for the purpose of innovation. AM is maturing into a disruptive technology allowing for the placement of payloads into Low Earth Orbit (LEO) and deep space with record-breaking cost reductions. Common AM practices allowing these cost reductions are the use of AM to produce whole systems with reduced amounts of material, manufacturing whole systems with fewer components, or constructing exotic geometries that are not obtainable by means of subtractive manufacturing but result in higher performance characteristics or efficiencies. During the preliminary literature review, it became apparent much of the research and development in the field of AM applications for spacecraft are on those systems providing opportunities for improved cost/benefit margins such as the propulsion system and human-spacecraft interfaces.
However, I believe there is missed opportunity in terms of innovation by not researching the use of AM in the other systems. In April 2022, NBC News published an article stating that the cost of sending a pound of payload into space on the space shuttle cost nearly 30,000 USD (in 2021 dollars), while the emergence of modern rockets and their systems has allowed the cost to drop down to around 1,296 USD on the Falcon 9 rocket (Chow, 2022). While this 95.68% reduction in cost is significant, our imaginations are coming up with more expensive, capable, and heavier payloads which further drives our need to find additional ways to improve efficiency and reduce weight. One way we may be able to do this is by reevaluating systems that can be manufactured through AM processes and have a relatively uncomplicated function and construction. This lack of complexity implies that a new, and hopefully innovative, design approach will add little risk to performance, reliability, and safety while providing the opportunity to shave a few pounds.
With the need to innovate in mind, I will design and manufacture artifacts representative of the traditional method by which modern spherical Pressure Vessels (PVs) are fabricated (essentially two hemispheres joined in the center by a weld) and a new, potentially innovative design only possible via AM and consisting of two unlike pieces that combine to form a spherical PV. The goal of this new design is to produce a PV that can withstand higher pressures as compared to a similar PV constructed through traditional means. Using FEA analysis and minor postprocessing, I will analyze both designs to evaluate if there is value in researching and re-thinking how we design, build, and use simple products. The results show both artifacts can withstand 100%, 125%, and 150% of their expected normal operating pressures. However, the “traditional” artifact will undergo catastrophic failure at a pressure that is about 2% greater than the point at which the “innovative” artifact experiences catastrophic failure
Modeling and Evaluation of Protonic Ceramic Fuel Cells for Flare Mitigation
Get PDFProtonic Ceramic Fuel Cells (PCFCs) are an emerging mid-temperature fuel cell technology that specializes in electrochemically converting chemical energy into electrical energy. These PCFCs have been suggested as a future technology for flare mitigation through the cogeneration of power and useful chemicals. PCFCs are here proposed to accomplish this purpose by utilizing the wasted methane and C2 components at these flaring sites to produce electricity, hydrogen, and aromatics. In this study, a numerical methane-fed protonic ceramic fuel cell model is developed utilizing recent advancements in PCFC fabrication, innovation, and experimentation. The model used a tubular PCFC geometry and implements mass and energy balances, as well as electrochemical, and kinetic equations solved using Engineering Equation Solver (EES) to predict the viability of the PCFC system. The system exhibits a very small power density on the order of ~0.01 W/cm^2, which is much lower than other fuel cells due to the chosen catalyst prioritizing the slower kinetics of methane dehydroaromatization. However, the results also indicate that the production of value-added aromatics allow the system to potentially be very economically friendly if the manufacturing costs can be brought down to 65% of their current costs. The realistic PCFC model is also compared and measured against competing technologies and is found to be competitive with current power production practices. The results of this study highlight the potential of PCFC technology to transform wasted energy into economic and environmental gains, offering a significant step forward in hydrogen-based sustainable energy practices
Reparative Analysis of OOHRP's Oklahoma and OSU Diverse Sexuality and Gender Collections
Get PDFThis presentation will focus on two Oklahoma Oral History Research Program collections, the Oklahoma and OSU Diverse Sexuality and Gender collections. As the OOHRP Digital Curation GRA, I will discuss my process of using controlled vs. homegrown vocabularies, more specifically the Library of Congress Subject Headings and FAST and the alternative vocabulary of the Homosaurus. I will go into discussion of how I approach, and what it looks like, creating metadata for these collections, along with the description writing process for these oral histories. There will also be a more broad discussion of reparative practices regarding 2SLGBTQIA+ oral histories and oral history collections
2024-25 budget.
No full textThe University of Central Oklahoma submits its budget for the upcoming fiscal year to the Oklahoma State Regents for Higher Education for final approval. This document is a copy of the approved budget for FY25