Open Research Oklahoma (Oklahoma State Univ.)
Not a member yet
42035 research outputs found
Sort by
Multi agent coordination through visual and tracking interaction using system identification method
No full textInsects, serving as model systems for swarming robotic agents, pose a challenge for fully explicating the mechanisms underlying their onboard sensing and feedback supporting such coordinated motions. This study addresses this gap by measuring untethered insects engaged in solo in-flight visual tracking tasks and employing system identification techniques to construct an experimentally consistent model of their visual tracking behaviors. Integrating measured experimental delays and their variation into a visually interconnected swarm model, the study develops theoretical and simulated solutions and stability limits. Linear stability and bifurcation analysis reveal delay distributions leading to a family of solutions with stable and unstable swarm center of mass locations. Additionally, the study experimentally records multiple flying insects tracking a moving visual stimulus, quantifying visual tracking delay variation and revealing average delays and standard deviations for solitary and group behaviors. These results quantify the role of visuomotor delay heterogeneity in flying insects and their role in supporting swarm cohesion through implicit communication. Further, the study analyzes recordings of flying honeybees in groups approaching a moving stimulus, uncovering a novel three-stage decision-making process involving pairwise interactions. Through neighborhood identification and testing against three regulation candidates, the study highlights individual decision-making capabilities, feedback rule changes, and PID interaction rules within aerial groups, offering insights with implications for mathematics, biology, and robotics. Finally, hypervelocity impact on space debris propagation is analyzed based on the multi-agent system identification technique. The primary objective is to capture and analyze debris impacts across the collector’s layers, focusing on interactions and debris transfer between layers. Advanced image processing techniques, including debris distribution analysis for each layer, were employed to evaluate the patterns and transitions of debris. Among the tested models, the second-order model structure provided the best approximation of debris distribution for single plates. This study provides valuable insights into optimizing future space debris collection systems and improving our understanding of debris dynamics in layered shielding structures. The findings contribute significantly to the fields of bio-inspired robotics, swarm dynamics, and space technology, paving the way for designing more effective multi-agent systems and resilient debris mitigation strategies
Suggested system for Oklahoma cotton farms
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
Impact of land use change on hydrological ecosystem services in the Tano River Basin in Ghana
No full textThe exploitation of natural resources, especially forests, land, water, and animal diversity in the world, has led to significant changes in the environment and the degradation of resources with serious consequences within the ecosystem. As the human population grows, so does the demand for these products, resulting in a major transformation on the earth's surface and causing a change in land use. The human dimension of natural resource extraction through various land use activities has significantly affected the services provided by the ecosystem, particularly those provided by rivers. This study focuses on examining the impact of land use change on hydrological ecosystem services using the example of the Tano River Basin, Ghana. The study used satellite images from 1986 to 2022 and generated land use and land cover (LULC) maps and then simulated for potential LULC in 2032 and 2052. The results revealed that the first interval between (1988–2003) showed a faster change intensity when compared to the second (2003–2013) and third (2013–2022) intervals. Across all the intervals (1986–2022), dense forests experienced a major decline of (-12.68%), followed by open forests with (-2.17%). Agriculture experienced a gain of (+12.72%), followed by built-up areas of (+2.09%). Simulation in the basin shows that open forests could witness the highest loss of 4.99% and 9.44%, while dense forests could also witness a loss of 0.07% and 0.25% in 2032 and 2052, respectively. Agriculture and built-up areas could also increase by 4.99% and 0.02% in 2032, and 9.61% and 0.03% in 2052, respectively. To determine the impact of land use on hydrology in the basin, water yield (SWY) was estimated using the integrated valuation of ecosystem services and trade-offs (InVEST). The study found that there was an increase in water yield which includes quick flow and baseflow from 1986–2022. Overall, my findings indicate that anthropogenic activities are contributing to land use change. Moreover, these findings show that land use change has a significant influence on water yield
Exploring freshmen need support during the COVID-19 pandemic: A naturalistic study
No full textWhen the world experienced the COVID-19 pandemic, it required the radical alteration of many facets of life. Educational institutions were no exception. All educational institutions had to discover and implement ways to provide education to their students even though their students could not see each other's faces, stayed six feet apart, and had to remain socially distant. These constraints ultimately required a redesign of many educational models and teaching plans to reflect an environment whose main priority was safety. Within this environment, students may have received a drain on their motivational supports of autonomy, competence, and relatedness. According to Self-Determination Theory, these motivational supports are necessary for the successful completion of tasks. From a selected university, 10 students were sampled that had experienced their freshman year during the COVID-19 pandemic. This study seeks to explore the motivational supports that these students experienced. As this was a naturalist study, data was collected through observations, interviews, and artifacts that were embedded within the setting
Insight into the deformation of unsaturated chemically stabilized and natural soils from the fundamental relation of water content-void ratio-suction under isothermal conditions
No full textThis study first constructed a conceptual framework for the interrelation between the water retention and the elastic deformation of soils caused by suction change under constant mechanical stresses and under isothermal conditions. For compacted expansive soils, a double porosity medium, the interrelationship between the virgin line of the water retention curve and the reversible volume change of the clay aggregates was established. The built conceptual framework was then employed to study the effectiveness of two stabilizers, an ionic agent, and a type of ground granulated blast furnace slag (GGBS), in improving the engineering properties of expansive and sulfaterich soils. For GGBS, sulfate-rich soils were treated, and extensive experiments were conducted to study swell-shrink behavior, unconfined compressive strength, suction change with curing time, and microstructural investigations via X-ray diffraction and environmental scanning electron microscope. It was found that GGBS treatment resulted in improving the 28-day strength of the tested sulfate bearing soils up to five times. An interesting finding from GGBS treatment was the occurrence of a delayed sulfate-induced heave that started beyond a month from the time of exposing the treated soils to water. For suction change with curing time, the GGBS treatment resulted in a consistent increase of matric suction at a certain period during curing from 0.05 to above 2 MPa, mainly due to the consumption of water in the hydration process and ettringite formation. The latter finding could be carried out to a further stage in future studies by correlating the suction increase with time to the strength development. Another significant finding presented in this study is that the comparison between the shrinkage curve measured at the macroscopic level of treated and that of untreated soils lays the possibility to understand the modification of the soil microstructures after GGBS treatment. This study was completed by developing an analytical hydro-physio mechanical approach that elucidates the mechanism of crack initiation based on the cavitation phenomenon, plastic limit concept, soil ductility, and tensile stress-tensile strength curve. Following this approach, it is proposed that cavitation phenomenon in micropores may explain the mechanism of cracking in compacted soils
Balancing the books: A reflective analysis of my academic journey through Oklahoma State University’s School of Accounting
No full textThis thesis aims to provide a comprehensive and reflective exploration of my educational journey within the Oklahoma State University School of Accounting, emphasizing the crucial role played by active participation in student clubs and internships. This essay seeks to uncover the transformative effects of academics, extracurricular and experiential learning on my personal and professional development
Computed tomography: Solving a historic problem in estimating sex and ancestry in forensic anthropology
No full textThe following study investigated the utility of computed tomography (CT) for the estimation of ancestry in forensic anthropology. While the usage of three-dimensional replicas of skeletal material has increased across the field of forensics, there is currently minimal literature demonstrating the utility of skull replicas for data acquisition for the purposes of estimating ancestry by forensic anthropologists. This study tested the effectiveness of CTs for ancestral data acquisition used by forensic investigators. The empirical data collected from a sample of Computed Tomography (CT) scans from cadavers of known sex and ancestry were used to produce three-dimensional (3D) virtual replicas. The accuracy of using the replica to correctly classify decedents within the correct sex and ancestral group was determined. Discussed within this study are the ancestral data which was effectively and ineffectively obtained from the 3D representations. Applying a multi-methods research approach, including radiologic data collection, macroscopic and metric data collection techniques, and statistical analysis, advantages and limitations of CT data for ancestral acquisition were identified
Impact of subsurface geochemical rock-fluid reactions on the permeability of hydraulically fractured Caney Shale of Southern Oklahoma
No full textProduction rate in hydraulically fractured reservoirs is expected to decline with time linearly in log-log space, with a slope of -1/2. However, most hydraulically fractured reservoirs witness a faster decline within the first 2 to 5 years of production, indicating a rapid loss of permeability. Several studies have tried to diagnose the predominant mechanism driving this loss, but the findings remain divergent at best. While some researchers aver subsurface geo-mechanical stress dynamics, others promote subsurface geochemical rock-fluid reactions as the predominant cause of this decline. It however remains imperative to understand the causes of the rapid permeability loss in order to develop the right solutions to mitigate the challenge.
This study evaluates permeability decline from the perspective of geochemical rock-fluid reactions considering these reactions are pervasive and impact micro and nano-scale fractures and pores within the reservoir. In this research, six experimental designs categorized under three thematic areas are employed to study geochemical rock-fluid reactions in hydraulically fractured Caney Shale. The first and second thematic areas employ static batch experiments where fracturing fluids are reacted with powdered rock and polished cored rock respectively. This helps to understand crucial post-fracturing reactions that adversely affect permeability. In the third category, dynamic core flooding experiments are adopted using artificially fractured rocks to assess the impact of geochemical reactions on petrophysical and mechanical properties of shales.
Results from this study reveal complex post-fracturing geochemical reactions in shale reservoirs. This is simplified as follows: Injection of highly oxygenated fracturing fluids into the subsurface triggers the oxidative dissolution of pyrites and other sulfides formed in reduced environments. This causes transient localized acidification leading to the dissolution of proximal minerals and increasing the ionic concentration of the fluid. These ions precipitate new minerals to occlude fractures and pore throats in the reservoir. This process ultimately causes the rapid permeability decline observed in hydraulically fractured shale reservoirs.
This study provides insight on adverse post-fracturing geochemical rock-fluid reactions. It also proffers substantial evidence to confirm the predominance of geochemical reactions in permeability loss in hydraulically fractured shale reservoirs. The study also has applications in geological carbon storage
Denitrification in stormwater constructed wetlands: Temporal variability and trace metal effects
No full textReduction of nitrous oxide (N₂O) production from nutrient rich stormwater constructed wetland ecosystems will enable a more environmentally sustainable system in urban and unmanaged areas. During the nitrogen metabolic reaction, N₂O can either escape to the atmosphere or be further reduced to N₂ by nitrous oxide reductase, which is the only known enzyme responsible for catalyzing this process. Denitrifiers need copper (Cu) to make this enzyme, but too much will inhibit the process, and too little will have no or few impacts. To investigate the effect of Cu on stormwater-constructed wetlands, two wetlands were selected here in Oklahoma. Laboratory denitrification enzyme activity assays and molecular analysis were performed to see the impact of spatial and temporal variability due to the Cu amendments. The treatment concentrations ranged from 0.01 µM (lowest) to 30 µM (highest). The results demonstrated that the effects of Cu amendments varied due to spatial and temporal variability. The ratio of N₂O to (N₂O+N₂) was also reduced or, in some cases, increased for the Cu treatments with varying levels, but not for the treatment with a fixed level of Cu. Furthermore, the addition of Cu amendments according to the United States Environmental Protection Agency’s requirements for aquatic ecosystem quality may not result in a substantial reduction in N₂O when compared to higher concentrations. For further investigation, Paracoccus denitrificans, a model denitrifier, was selected for Cu amendment experiments. It was found that high concentrations of Cu treatment reduced the N2O production rate in P. denitrificans-incubated systems. The quantitative polymerase chain reaction analysis with nosZ operational taxonomic unit (OTU) 1 and nosZ clade II primers showed that Cu additions have a general inverse relationship between N₂O production rate and nosZ gene abundance
Food accessibility and food insecurity on campus: Experiences of international students at Oklahoma State University
No full textBackground: The high prevalence of food insecurity on university campuses has prompted many institutions, including Oklahoma State University (OSU), to implement strategies to curb the situation, such as providing food assistance programs. While some research has explored university food insecurity status and awareness and utilization of these food resources, limited attention has been given to international students specifically, who may face challenges in meeting their food needs in an unfamiliar environment.Objectives: In the present study, we aimed to evaluate international students’ food insecurity status; awareness, utilization, and barriers to access of food resources; and coping strategies adopted in the face of limited food resources.Methods: International students of OSU were recruited through their university email to participate in an anonymous online survey in February 2024. A total of 215 participants responded to questions gauging their food insecurity status; awareness, utilization, and barriers to utilization of food assistance programs on campus and in the community, as well as international markets in Stillwater; and utilization of coping strategies. Participants also provided information on the availability of international foods at these locations. Socio-demographic data were also collected. The USDA Six-item Short Form Food Security Survey was used to assess food insecurity status. Descriptive analysis was used to summarize data.Results: On average, participants were aged 28.8±8.3 years, mostly male (55.2%), graduate students (92.6%), single (68.3%), worked part-time (63.6%), not receiving any financial aid (65%), and lived off campus (65.2%). The prevalence of food insecurity was 45.7%. Of the participants who experienced some level of food insecurity, 31.2% had low food security and 14.5% had very low food security. While 91.5% were aware of at least one food assistance program, only 78.7% reported using at least one program. Participants were most aware of Pete’s Pantry (83.5%), Our Daily Bread Community Food Resource Center (69.3%) and Our Daily Bread Mobile market (57.4%), while only 55.6%, 54.2% and 32.5% used them, respectively. However, only 22.2%, 23.5% and 14.7% of participants indicated that these programs offered international foods, respectively. Major reasons international students reported not using the food assistance programs were schedule conflicts/hours of operation (30.2%), feeling like other people needed the food more (24.7%), and the potential that the foods available would not meet their needs (24.7%). When asked about international food markets specifically, majority of participants reported being aware of the Himalayan Grocery Store (88.7%) and Crepe Myrtle Asian Market (56%), but only 76.8% and 42.9% reported purchasing food from them, respectively. Most international students adopted a coping strategy when faced with limited food resources including cutting down the size of their meals (73.9%), eating less healthy meals (66.9%), and purchasing cheap, processed foods (66.3%).Conclusion: A large percentage of international students struggle with food insecurity. While they are aware of food assistance programs available on the OSU campus or in the Stillwater community, their utilization remains sub-optimal. The limited availability of international foods may be a barrier to utilizing these programs. We recommend that OSU and the Stillwater community should work to provide international foods at their food assistance programs and determine what hours of operation would allow international students to benefit most. Future studies should investigate the factors associated with non-use of these food assistance programs and identify what specific international foods should be provided