Open Research Oklahoma (Oklahoma State Univ.)
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Wheat yield prediction using machine learning, proximal sensing, nitrogen and climate data for Oklahoma and North Africa and the evaluation of NDVI response index consistency using proximal sensors and satellites
No full textAccurate and timely crop yield prediction is critical for optimizing food availability, forecasting economic returns, and setting market prices. It also allows in-season management adjustments, such as optimization of nitrogen (N) fertilization. Machine Learning (ML) have gained prominence for handling big data and modeling non-linear relationships. This study evaluates the effectiveness of using ML with climate variables, canopy sensing data, and N application rates to predict wheat yield in Oklahoma and North Africa. Data were collected from 41 site-years in Oklahoma and 13 site-years across North Africa. The dataset included climate variables, canopy sensing data (NDVI), and pre-plant N application rates. In Oklahoma, the CatBoost model achieved the highest performance, with an R² of 0.81 and an RMSE of 0.63 t/ha. The feature set for Oklahoma was optimized to 13 variables, including NDVI at various growth stages, monthly temperature, rainfall, and evapotranspiration. In North Africa, CatBoost model performed best, with an R² of 0.42 and an RMSE of 0.92 t/ha. The feature set for North Africa was simplified to 14 variables, focusing on NDVI measurements, N rate and climate variables like monthly rainfall and temperatures. This research highlights the potential of integrating ML, remote sensing, weather, and N management for accurate yield prediction. Aside from yield prediction, another important concept for in-season N recommendation is the Response index NDVI (RINDVI), which evaluates crop responsiveness to additional N fertilizer. In a separate study,the response index RINDVI was calculated using NDVI values from GreenSeeker™ and satellite platforms (PlanetScope and Sentinel-2). NDVI data were collected from both the N-rich strip (high N application) and the standard practice strip. High NDVI correlations between GreenSeeker™ and satellites enabled calibration using GreenSeeker™ as a reference. However, even after calibration, GreenSeeker™ consistently displayed a broader range of RINDVI values, leading to differences in N recommendations. PlanetScope showed the closest alignment with GreenSeeker™, with an average underapplication of 4 kg/ha, though deviations of up to 33 kg/ha were observed. The study demonstrated underapplication of N when using satellites, compared to GreenSeeker™ as a reference within the current context of agricultural practices for the N-rich strip
Senior design project: Blue hydrogen production
No full textThe demand for hydrogen continues to rise as it becomes more widely used in a variety of industries, including food, petroleum refining, electronics, and transportation1. Company A has requested an in-depth preliminary design of a new blue hydrogen production facility located in the Gulf Coast region to meet the rising demand. Company A defined many of the constraints and specifications for the new production plant, including the production target of 250 MMSCFD (Million Standard Cubic feet per day) of hydrogen on average, which would make our proposal the largest known hydrogen production plant in the world2,3. To achieve the targeted production, our design team has developed a novel facility comprised of eight reactors and two intensive separation units, along with many auxiliary operations. The design was analyzed, optimized, and modeled using a combination of Aspen HYSYS version 14, PolymathPlus, and Aspen Energy Analyzer version 14. The basic process route is as follows: Natural gas is processed via ZnO bed, sent to a pre-reforming reactor, then refined in a set of steam methane reforming reactors before entering the water-gas shift system and finally purifying to 99.99% hydrogen via pressure swing adsorption beds. The decision to supersede the autothermal reforming reactor (ATR) with a steam methane reforming reactor (SMR) was done in the pursuit of efficiency. The isothermal nature of a SMR permits a much greater methane conversion rate of 99% via PolymathPlus, allowing for a much safer overall process due to the reduction of flammable fluids needed to achieve target production. Safety was among our top criteria when designing; as a result, metallurgy, controls, and inherent safety were diligently selected and implemented. Nearly all equipment was designed using 316 stainless steel to avoid corrosion and hydrogen embrittlement. In areas with both corrosion and high temperatures, the team employed nickel alloy. Equipment under incredible heat will be constructed using 310 stainless steel due to its superior heat resistance. Ceramic wool insulation will be installed in the direct-fired heater, the pre-reformer, and the SMRs. Environmental impact was also heavily considered and satisfied using a monoethylamine (MEA) absorption system. The system is designed to be wholly environmentally friendly through the sequestration of MEA yearly and the sale of 100% of the CO2 produced to the beverage industry. Additionally, the facilities’ chosen location in Livingston, Texas allows the plant to employ renewable hydroelectric and solar energy for the operation of the plant. This further reduces scope 2 emissions to a negligible measure. Overall, the plant is designed to capture 100% of all greenhouse gases short of any spontaneous incidents. Over the life of the project, the production plant is predicted to make nearly 700 million. The discounted cash flow rate of return (DCFROR) or yield rate is just under 21%, which places the project close to 6% above the hurdle rate. The yearly operating cost of the entire process comes to just over $760 million, and under these conditions, the payback period is estimated at nearly 9 years. Overall, the economics prove appealing when considering the lack of economic variability identified by the sensitivity analysi
Institutions and stakeholder management in entrepreneurship
No full textThe three essays in this dissertation study how institution-driven stakeholder management shapes entrepreneurial outcomes. The first paper develops a theory that distinguishes entrepreneur-driven from institution-driven stakeholder management in entrepreneurship. It conceptualizes how institutions—not just entrepreneurs—can initiate, structure, and constrain stakeholder engagement through enforcement- and legitimacy-based mechanisms. This theory highlights differences in who initiates stakeholder management, the timing of engagement, the selection of stakeholders, and the underlying logics driving the process. By introducing a multilevel framework, this paper reframes stakeholder management as a dynamic interplay between institutional influence and entrepreneurial discretion. The second paper investigates the psychological consequences of institution-driven stakeholder management by analyzing how South Korea’s 2018 minimum wage hike—an exogenous regulatory shock related to stakeholder management—impacted entrepreneurial mental health. Drawing on person–environment fit theory, the study theorizes that sudden institutional shifts can disrupt the fit between entrepreneurs’ personal resources and external demands, leading to increased psychological distress. Using a difference-in-differences design with longitudinal data from the Korean Welfare Panel Study, the analysis includes 51,734 individual-year observations between 2015 and 2021. Results show that depression levels significantly increased among entrepreneurs relative to non-entrepreneurs following the policy change, especially for those experiencing financial strain, highlighting the role of institutional pressures in shaping mental well-being. The third paper applies the external enabler framework to examine how constraint-based institutional change—specifically, employment protection legislation —influences entrepreneurial activity in the United States. Leveraging the staggered adoption of the implied contract exception across states from 1972 to 1992, the study uses a difference-in-differences approach with 1,892 state-year observations drawn from the U.S. Census Bureau’s Business Dynamics Statistics. Findings indicate that employment protection legislation significantly reduces corporate entrepreneurial activity. The results suggest that employment protection legislation imposes rigidities that undermine firms’ capacity for internal innovation and adaptation. Together, these essays contribute to the literature by theorizing how institutional frameworks influence stakeholder management in entrepreneurship and by testing both the intended and unintended mechanisms
Antimicrobial effectiveness of X-tox proteins
No full textAntimicrobial proteins and peptides (AMPs) are crucial components of innate immune systems in multicellular organisms, serving as effectors against pathogen infections. Insect defensins and their homologs, including X-tox, represent a diverse AMP family, most of which exhibit activity against bacteria or fungi. These peptides share a conserved three-dimensional αβ fold stabilized by three disulfide bonds characteristic of defensins. In Manduca sexta, four X-tox variants have been identified, arising not from gene duplication but through exon duplication, sequence divergence, and alternative splicing. The M. sexta 5-tox gene comprises six exons, with exons 2 through 6 each encoding a tox domain. This project aims to investigate whether specific isoforms of the X-tox AMP can gain functionality and to determine if different isoforms can act synergistically to enhance the insect’s immune response
Serving success: A strategic communication plan for kickingbird pickleplaza
No full textThis thesis explores the comprehensive development of a brand identity and communication strategy for KickingBird PicklePlaza, a new pickleball facility in Edmond, Oklahoma. Capitalizing on the national surge in pickleball participation—which has grown 39% since 2021—this research addresses the opportunity to create a cohesive brand identity that resonates with the facility's diverse user base. Through methodological triangulation incorporating secondary research on industry trends, primary research via focus groups with 20 participants, and A/B testing with 229 respondents, the study identified key user personas, brand elements, and communication preferences. The research revealed a strong emphasis on community connection, with 79.1% of survey respondents reacting positively to narrative messaging centered on hometown spirit. These insights informed the development of a comprehensive visual identity including a logo that synthesizes feedback from closely split preferences (48.5% vs. 45.0%), a color palette connecting to both the sport and local heritage, and the tagline "KickingBird PicklePlaza: Come. Connect. Compete." which received 67.2% preference among respondents. The resulting strategic framework includes implementation plans for social media engagement, promotional content creation, and measurable success metrics, positioning KickingBird PicklePlaza as a premier destination for play, community, and growth in the expanding pickleball landscape
Eyewitness testimony and gender in violent crimes
No full textThe present study experimentally investigates the effect of gender on the accuracy of eyewitness testimony. I ask whether women or men give a more accurate testimony after witnessing crimes with varying levels of violence. I also examine whether the gender of the victim affects the accuracy of the testimony. Participants are randomly assigned to a vignette that describes a crime that contains either no violence, threats present, or physical violence. The victim will either be masculine or feminine presenting. Participants are then asked to recall details about the victim, perpetrator, and crime setting. I expected that women would perform better in the threat of violence condition or violent condition than the no violence condition. I also expected that women would provide more accurate testimony overall, and that women would provide more accurate details of victims who are also women. My hypotheses were not supported, although small differences did emerge, suggesting that gender and violence may play a role in producing accurate testimony, albeit not a large one. Results also showed that the level of accuracy was significantly impacted by the participants’ confidence in their answers
Characterization of an aircraft turbo-generator design space with a shared turbine-electric rotor disk
No full textThis dissertation presents design considerations such as the impact of geometry, generator type, operating temperature, and rotational speed on the design and performance of a novel configuration of turbo-generator. The unique shared-rotor disk architecture reduces total part count by radially ”sharing” the rotor of the generator and the turbine. This allows power to be extracted, while retaining axial engine flow that can then be used to generate thrust. The architecture has several additional advantages, a reduction in weight when compared to a geared turbo-generator, the ability to quickly retrofit existing engines, and the ability to operate at a different rotational speed than the main shaft. A representative 10-kW sub-scale design point was specified and investigated, to evaluate key parameters such as the diameter ratio of turbine to overall rotor assembly, operating temperature, tip speed, and generator type. Results from detailed evaluation utilizing thermal, mechanical, and electromagnetic finite element analysis showed that the principle limiting factor was mechanical implementation of the generator structure, as opposed to the turbine structure. This observation necessitated creation of novel generator rotor configurations to handle temperature and stress induced by thermal expansion. One configuration utilizes a novel slide joint to alleviate turbine thermal expansion, whereas the other configuration utilizes turbine thermal expansion to create the required retaining sleeve interference fit. A bench test experiment involving a generator in both delta and star winding configurations was conducted to verify manufacturer data. Using measurements of the physical generator and manufacturer specifications, a finite element model of the existing generator was created and used as a point of comparison with the proposed shared-rotor and a conventional 13-kW turbo-generator. Comparisons of key figures of merit such as weight, specific power, component losses, and overall efficiency were made between different turbo-generator configurations. The proposed high-current-density, shared-rotor disk configuration had the largest specific power, around 22.5% greater than the proposed turbine with existing generator and around 264% greater than the conventional 13-kW turbo-generator. However, with notable room for improvement, the shared-rotor generator configuration was found to be between 1-5% less efficient than the existing generator coupled to the proposed turbine. The study culminates in broad recommendations for design and implementation of shared-rotor turbo-generator systems
Associations among family functioning, food security, and diaper need in Oklahoma
No full textBackground: Diaper need and food insecurity are prevalent forms of material hardship among low-income families with young children. Family systems theories suggest that family functioning can affect and be affected by material hardship.
Objective: The purpose of this thesis was to examine the associations between family functioning (chaos and flexibility), food insecurity, and diaper need in low-income families in Oklahoma.
Methods: Data were collected in a cross-sectional online survey from caregivers of at least one child in diapers (N = 91). Participants were recruited at community service agencies across Oklahoma from April to May 2024. Measures included the Family Adaptability and Cohesion Scale IV-Short Form (family flexibility and chaos), the USDA Six-Item Short Form (food insecurity), and the National Diaper Bank Network Diaper Check (diaper need). Pearson correlations, chi-square analysis, and t-tests were conducted to assess associations among these variables.
Results: A large portion of participants reported food insecurity (72%) and diaper need (52%). Participants were more likely to have diaper need when they also reported low or very low food security (X2 = 15.9, p < .001). Results indicated a significant negative correlation (r = -0.34, p < .001) between family flexibility and chaos, showing that greater flexibility was associated with lower chaos. Food insecurity was positively associated with family chaos (p = .016) and negatively associated with family flexibility (p =0.12), showing that food insecurity was more common in families with lower levels of functioning. However, no significant associations were observed between family functioning and diaper need, indicating that diaper need may be more directly related to financial constraints rather than family dynamics.
Discussion: These findings highlight that while family adaptability may buffer the effects of food insecurity, direct financial interventions are essential to address diaper need. Expanding access to both nutrition and diaper assistance programs could support family well-being by reducing economic stress and enhancing family stability