Open Research Oklahoma (Oklahoma State Univ.)
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Assessing coaxial collector performances: Field data and analysis
No full textSince the development of Ground Source Heat Pumps (GSHPs), there have been mostly three types of borehole heat exchangers in use, single and double U-pipes as well as coaxial, the latter being seldom installed. Most earlier work has thereby been focusing on the classic U-tube solutions. This work aims at providing more information on coaxial heat exchangers. Field data from 11 installations having coaxial borehole heat exchangers has been gathered in this work and measured effective borehole resistance as well as pressure drop have been presented and compared to calculated values. The Hellström approach as well as correlations for pressure drop have been implemented. Significant deviation from theory has been observed regarding the pressure drop (75% average absolute relative error) as well as the effective borehole resistance, albeit to a lesser extent (33%). An exploration of the geometrical parameter space (length, brine concentration, fluid temperature and inner diameter) has been carried out, giving insights into potentially better coaxial designs
Understanding the effects of warming on nitrogen cycling dynamics in a tropical forest
No full textTropical forests have an exceptional capacity to sequester carbon, support biodiversity, and cycle nutrients. Ample soil nitrogen (N) in these forests allows high rates of primary production and rapid regeneration. Nitrogen is regulated by microbial communities, which can be free-living in the soil and leaf litter (asymbiotic) or in symbioses with certain trees. Climate warming is predicted to increase microbial N fixation and may alter the growth of N-fixing trees, which are major N inputs in tropical forests. To investigate the effects of warming on both the asymbiotic and symbiotic components of the N cycle in tropical forests, we analyzed soil and leaf litter samples as well as annual seedling census data from a warming field experiment in Puerto Rico. Amplicon sequencing of the 16S and nifH regions of our samples revealed that microbial community composition was significantly altered by warming. We found that asymbiotic N fixation rates were increased under warming, and this increase in fixation was partially mediated by the change in the N-fixing bacterial community, at least in the leaf litter. Nitrogen-fixing seedlings exhibited a higher growth rate than non-fixers under warming, and this growth advantage was absent under ambient conditions. The growth of N fixers was reduced by a higher proportion of neighboring N fixers, but this competitive effect was only significant under warming. Finally, seedling growth increased following hurricane disturbance before significantly decreasing, possibly because a flux of growth-supporting light and nutrients after the hurricane quickly dissipated. This growth increase and subsequent decrease was significantly exaggerated in N fixers under ambient conditions. These results tentatively indicate that the anticipated increase in N fixation under warming confers N fixers a growth advantage that alters neighborhood growth dynamics and growth response to hurricane disturbance. These effects of warming on both asymbiotic and symbiotic N fixers suggest that warming increases N flux from the atmosphere into this tropical forest, but it remains unclear how the other components of the N cycle are altered, including N mineralization. Future research should aim at understanding how climate change influences the full N cycle in tropical forests
Analysis of unmanned aerial system integration and the impact of rules and regulations on safety of flight within the United States of America’s National Airspace System
No full textThis study provides an analysis of how the Federal Aviation Administration (FAA) policies on Unmanned Aircraft Systems (UAS) integration have impacted the safety of airspace operations within the National Airspace System (NAS). The study sought to determine if an impact exists and, if so, if the impact was positive or negative. Despite state-level laws governing the usage of UASs at the recreational and commercial level, this study only analyzed the integration of UASs at the federal level. Utilizing the Aviation Safety Reporting System (ASRS) and the National Transportation Safety Board (NTSB) accident database, a mixed methodology study was conducted to analyze three distinct time periods: prior to 2013, 2013-2014, and 2015-present day. Through the collection, organization, and analyses of incidences and accidents involving UASs, a descriptive analysis was conducted to analyze the impact of rules and regulations on UAS integration in the NAS. The findings also provided a metric for understanding how integration of UASs has been impacted by regulations, growth in the industry, and ongoing efforts to educate and train the UAS sector. Lastly, this study presents approximately 30 years of historical data and provides a baseline to assist in future measurement of ongoing integration success or failure
Investigation of an optimal approach to 3D print small scale wings with minimal post processing
No full textThis paper will discuss an optimal approach to fully 3D printing a wing with internal structure and with minimal post processing required. The goal of this research is to determine which factors of 3D printing can be changed to then manufacture a 3D printed wing. A comparison between the 3D printed wings and fiberglass composite wings was then studied to demonstrate the differences in stiffness, strength to weight ratios, manufacturing costs, and fabrication times of each type of wing. The methods of testing and fabrication were determined by those readily available to students at the graduate student design lab at Oklahoma State University. To begin, research was done to determine what use cases composites and 3D printing have within the aerospace industry to determine whether there would be a use case for 3D printed wings. Once determined that there was a use case for 3D printed wings, research was done to determine what factors could be changed when printing such as plastic type, layer height, orientation, infill type/density, wall thickness, print speed, and raster angle. Some of these factors were then tested to narrow the final selection of the optimal case following the ASTM D790 bending test standards while others had extensive research done to determine what was considered optimal. Results from the ASTM D790 bending tests and research done were then used to test print the wings to determine if the results made sense with the geometry of the wing. After wings were successfully printed, they were then compared to composite wings that were manufactured using traditional fabrication methods seen in the graduate student design lab. Each set of wings underwent a bending test to determine stiffness and strength to weight ratios of the wings. Once the results of the wing bending test were obtained, cost and fabrication time were compared to determine a more holistic comparison between the two manufacturing methods. Overall results showed that the fiberglass composite wings were stronger and had a higher stiffness, however the 3D printed wings were significantly quicker to manufacture and cost a fraction of what the composite wings cost to fabricate
Compactifying sufficiently regular covering spaces of compact 3-manifolds
No full textIn this paper it is proven that if the group of covering translations of the covering space of a compact, connected, P²-irreducible 3-manifold corresponding to a non-trivial, finitely-generated subgroup of its fundamental group is infinite, then either the covering space is almost compact or the subgroup is infinite cyclic and has normalizcr a non-finitely-generated subgroup of the rational numbers. In the first case additional information is obtained which is then used to relate Thurston's hyperbolization and virtual bundle conjectures to some algebraic conjectures about certain 3-manifold groups.Mathematic
LEAN healthcare: Evaluation of the discharge process at mid-sized hospital
No full textIntroduction/Objectives: A team of 8 osteopathic medical students were tasked with learning and implementing the LEAN process. LEAN is a philosophy of process improvement through creation of standard workflow and minimization of waste. Oklahoma State University Center for Health Systems Innovation in partnership with Oklahoma State University Medical Center tasked the team with identifying inefficiencies embedded within the Discharge Process specifically, patients being discharged from inpatient units. This research discusses the teams findings and recommendations provided to hospital leadership.Methods: The Medical student team participated in lecture and simulation instruction led by two LEAN trainers to obtain knowledge of the use of LEAN in healthcare settings. The Students involved performed Gemba walk at a local hospital on Medical/Surgical floors specifically observing tasks related to discharging patients, interviewed key players that contribute to the discharge process, obtained perspectives on the current state, known inefficiencies, and recommendations for change. Documentation was obtained for current protocols/standard operating procedures. The team shadowed staff and collected data points for 40 patients including date of discharge, time discharge order was signed, time After Visit Summary was printed and signed, time patient exited unit, and time patient was marked ‘Out of Room’ on EPIC. Information was collected regarding events associated with discharging the patient through observation and communication with staff involved. A flow chart was then created to map out the current state for discharging a patient, identified areas of inefficiencies, notated with ‘Storm Clouds’ were shown on the flow chart. Students then analyzed inefficiencies and potential recommendations evaluating benefit vs. effort, controllable vs. non-controllable, and cost vs. no cost. At the end of the project, the team presented LEAN Discovery Recommendations to hospital leadership.Results: The current state of the discharge process was divided into three stages. Stage one begins when the patient is admitted to the hospital and ends the morning of discharge. Stage two takes place from pre-rounds to when the discharge order is placed in Epic. Stage three begins after the discharge order is placed and ends when the Environmental Services Department is notified of patient's departure. During stage one, we observed inconsistent communication between care teams, a lack of standardization, and no defined role for collecting a discharge pharmacy. Stage two showed a lack of standardization amongst physician teams and inconsistent communication of potential patient discharge between hospital leadership and nursing staff. Inefficiencies observed in stage three consisted of discharge orders placed with pending tasks and difficulties securing patient transportation.Conclusions: The team’s investigation of this topic identified themes of inefficiencies: standardization, defined roles, and communication. With the implementation of LEAN training students produced potential recommendations of cost-effective interventions and “best practice” procedures for key players involved
Winter barley, oat and triticale tests, 1974
No full textThe Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Social presence and brand narrative engagement in branded virtual worlds: Exploring their effects on brand immersion and purchase intention for fashion brands
No full textThe present research elaborates on the concept of a Branded Virtual World (BVW) for fashion brands, establishing four distinct BVW categories determined by the level of social presence and brand narrative engagement within the BVW environment. Building upon this typology of BVWs, this study aims to examine the impact of BVWs on brand immersion and purchase intention, exploring the varying levels of social presence and brand narrative engagement within the BVW environment. A 2 (brand narrative engagement: high vs. low) X 2 (social presence: high vs. low) between-subject experiment design was utilized. Videos were created to represent the four types of BVWs, utilizing the gaming platform of Animal Crossing in collaboration with the fashion brand H&M. A total of 176 female adult U.S. consumers were recruited. The results revealed the significant impact of brand narrative engagement on brand immersion and purchase intention, supporting H1 and H2. However, the interaction effect between brand narrative engagement and social presence was not significant on either brand immersion or purchase intention. Thus, H3 and H4 were not supported
Low energy availability in collegiate softball athletes
No full textChronic and problematic conditions of low energy availability (LEA) have been identified as the underlying cause of Relative Energy Deficiency in Sport (REDs), which is a condition that may lead to impaired physiological function and long-term health consequences. The REDs “spotlight” has often been on endurance and weight-restricted sports, but research in other team sports is limited. PURPOSE: To identify the prevalence of LEA in collegiate softball athletes during preseason and assess differences in health metrics based on risk of LEA. METHODS: Twenty-three females who were 20±2 years old, 165.5±32.5 cm tall, weighed 77.3±12.4 kg and were members of the Oklahoma State University softball team participated in this study. All participants provided informed consent prior to completing a single lab visit consisting of injury history and sleep quality questionnaires, a total body Dual-energy X-ray Absorptiometry (DXA) scan, and a 24-hour dietary recall. The Harris-Benedict equation was used to calculate basal metabolic rate (BMR), with an activity factor of 1.5 to calculate total energy expenditure (TEE). BMR was subtracted from TEE to estimate exercise energy expenditure (EEE). Energy availability was calculated and reflected as kcal/kgLM/day: high risk <30 (n=15); moderate/low risk ≥30 (n=8). Group comparisons were made for anthropometrics, questionnaire responses, body composition, and skeletal health using Independent t-tests and Levene’s tests for equality of variances (α≤0.05). RESULTS: Sixty-five percent of athletes were at high-risk for LEA, indicating a high prevalence of this condition in this cohort. LEA groups were similar for anthropometrics, injury history, and most DXA measures (p≥0.131). However, athletes in the high-risk LEA group reported clinically poor sleep quality (5.6±3.1) and lower bone mineral density Z-Scores (0.7±1.1), compared to moderate/low risk who had normal sleep quality (4.3±0.7) and higher Z-Scores (1.4±0.9). DISCUSSION: The results of the current study showcase the high prevalence of LEA in a non-weight restricted and understudied sport. In addition, those at high-risk for LEA suffered worse sleep and displayed lower skeletal health measures, potentially putting them at an increased risk for injury. These findings provide a foundation for future research by exposing interventional targets for at-risk female athletes
When stories do not matter: An examination of legitimate distinctiveness in pooling equilibria
No full textIf investors cannot perceive differences among ventures, how can they decide which ventures to support? By marrying signaling theory with the legitimate distinctiveness literature, I argue that a pooling equilibrium—a context wherein investors cannot discriminate higher quality signalers from lower quality signalers due to unreliable signals—will limit the benefits of differentiation (e.g., an innovation that differentiates from peers) as a resource acquisition strategy. In this regard, I argue that the type of equilibrium present will moderate the relationship between legitimate distinctiveness and access to resources.
Following the legitimate distinctiveness literature, I theorize that the benefits of legitimate distinctiveness depend on the possibility of actually being able to establish perceptions of both conformity and distinctiveness in the minds of audiences. That is, if an environment is such that audience members cannot perceive one or both properties, legitimate distinctiveness cannot be established, and benefits may not be forthcoming. Thus, I argue that the benefits accrued from legitimate distinctiveness to increase access to resources will hold in a separating equilibrium; but in a pooling equilibrium different dynamics may be at play. I, thus, theorize that the presence of a pooling equilibrium limits the effect of legitimate distinctiveness on private equity funding because investors cannot perceive differentiation signals to discriminate higher quality ventures from lower quality ventures.
This dissertation contributes to signaling and entrepreneurship literature by being one of the first studies to explore a pooling equilibrium in the entrepreneurial process. This dissertation also relieves the tension in the conformity versus distinctiveness paradox, by suggesting that the signaling context significantly influences this decision for entrepreneurs, contributing to the integration of institutional theory and strategic management. I find support for my theorizing. In particular, the positive effect of distinctiveness and conformity on increased access to resources when assuming the existence of a separating equilibria. In a pooling equilibrium, though, the positive relationship between conformity and access to resources is supported, while post hoc analysis reveals the negative relationship between distinctiveness and access to resources