K-State Electronic Theses, Dissertations, and Reports: 2004 -
Permanent URI for this collectionhttps://hdl.handle.net/2097/4
This is the collection for doctoral dissertations and masters theses and reports submitted electronically by K-State students. Electronic submission of doctoral dissertations was required beginning Fall semester 2006. Electronic submission for masters theses and reports was required beginning Fall 2007. The collection also contains some dissertations, theses, and reports from the years 2004 and 2005 that were submitted during a pilot test project. Some items before 2004 have been digitized and are available in K-State Electronic Theses, Dissertations, and Reports: pre-2004. Check the Library catalog for dissertations, theses, and reports not found in these collections.
All items included in this collection have been approved by the K-State Graduate School. More information can be found on the ETDR Information Page. Items within this collection are protected by U.S. Copyright. Copyright on each item is held by the individual author.
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Item Open Access Investigating legged robots' mobility control on simple surfaces using a light-weight machine learning architecture(2025) Morton, CoryEstablishing a long-term human presence on the lunar surface necessitates robust autonomous systems capable of navigating unpredictable terrain with limited external control. Surface mobility is challenged by diverse slopes, abrasive regolith, and low-gravity conditions, all while operating under strict power and processing constraints. This thesis investigates the application of Deep Reinforcement Learning (DRL) to train a neural network-based motion controller for a legged robotic platform, with the goal of deploying the trained controller to a low-resource microcontroller. Using the MuJoCo-based Ant environment from the Gymnasium API, a DRL agent was trained with the Proximal Policy Optimization (PPO) algorithm to develop stable and adaptive locomotion policies. The trained model was then quantized and converted using the ExecuTorch framework for deployment on an Arduino Nano BLE 33 Sense microcontroller, representative of the limited processing resources expected in real-world space missions. Performance was evaluated by comparing the behavior of the controller on the development machine to its performance on the microcontroller. Results showed that the deployed model could maintain similar performance to the trained model. While performance degradation due to conversion and hardware limitations was observed, the study offers a practical roadmap for bridging high-performance simulation with real-time embedded control. These findings contribute to advancing autonomous mobility systems for extraterrestrial exploration, emphasizing the potential of DRL and TinyML to operate effectively in low-power, communication-limited environments.Item Open Access Lead in Kansas City soils: Lead source tracking and assessment of wastewater-derived phosphate for fertilization and lead remediation(2025) Murphy, JackLead is a toxic, naturally occurring element in soil that is widely elevated in surface soils due to anthropogenic Pb pollution. Various sources have contributed to soil Pb contamination such as leaded gasoline, lead paint, and industrial activities. Knowing the contributors of Pb to soil is crucial for protecting soils from further contamination, choosing mitigation methods, and public health. Isotope tracing is a source-tracing method that strives to utilize natural isotopic variations for the discernment of different sources of the element. For Pb, this method can identify anthropogenic contributions in soil by observing the similarity in ratios between the soil and the unique isotopic signature sources can have. The first objective of this study is to identify the major sources of Pb contamination in Kansas City, MO. Surface soils (0 to 15 cm) were collected from various residential and vacant sites in the area. Three near-pristine subsurface soil cores from the Konza prairie was also collected as a background. Soils were digested using USEPA method 3051, and concentrations were determined using an inductively coupled plasma- optical emissions spectrometry (ICP-OES). Diluted samples were analyzed for isotope ratios in ICP- Triple quadrupole mass spectrometry (ICP-QQQ). Results showed that Pb isotope ratios of Kansas City sites overlapped with leaded paint and gasoline ratios. Konza Prairie Pb isotope ratios were distinct from Kansas City sites. Phosphorus is a vital nutrient essential for the global agricultural system and maintaining food security for the world’s growing population. As the population continues to grow, so does the demand for these fertilizers for increasing crop yields. Phosphorus fertilizers are derived from phosphate rocks which are a non-renewable resource and will soon be scarce due to their growing demand. Wastewater streams from agricultural and urban areas are a renewable resource that contain high concentrations of nutrients such as P and can be extracted from wastewater in the form of reclaimed nutrient products (RNPs). The objective of the second study is to evaluate the effectiveness of RNP product as an alternative fertilizer and a potential stabilization treatment for Pb in contaminated soils. The RNP for the study was selected based on wet chemical methods and X-ray diffraction (XRD) characterization. The selected RNP had a total P concentration of 12.57% and a citric soluble P content of 35.89% (% of total P). Two P species were identified by XRD; 84.8% octacalcium phosphate (OCP), and 15.2% struvite. Three soils were acquired from a vacant lot different levels of Pb and classified as mild (208 mg/kg), moderate (323 mg/kg), and extreme (2418 mg/kg). Treatments included four P sources, treatments, ammonium polyphosphate (APP), triple superphosphate (TSP), calcium phosphate based RNP, struvite and a control. Phosphorus treatments were applied to soils at equal rates. Completely randomized block design (RCBD) was used with 3 blocks for each plant type (leafy, lettuce and root crop, radish). Lead concentrations were determined with Graphite Furnace Atomic Absorption Spectrophotometry (GFAAS). Other elemental concentrations were determined with ICP-OES, and diluted plant samples Pb isotope ratios were determined with ICP-QQQ. Struvite and RNP treatments showed significant reductions in Pb concentrations for root and leafy crops. Lead concentrations in mild and moderate soils did not exceed FAO/WHO maximum Pb levels for leafy crop. Struvite, RNP and APP showed significant increases compared to the control in P uptake, despite initial excess soil P masking treatment effects. Agronomic levels of P addition had no significant effect on soil Pb bioaccessability. Plant Pb isotope ratios of unamended controls were significantly different than soil Pb isotope ratios, while P treated plants remaining close to the original soil ratios, suggesting selective uptake and/or translocation of soil Pb upon natural attenuation.Item Open Access Talk to Me How I Talk: The Role of African American Vernacular English in Mental Health Diagnosis and Communication(2025) Bell, Char'daeThis qualitative study explored how African American millennial women understood their mental health diagnoses and whether language, particularly African American Vernacular English (AAVE), influenced that understanding. Guided by Critical Discourse Analysis and Critical Theory, the results demonstrate how diagnostic communication intersects with culture, language, and identity. Twelve participants were interviewed to capture their lived experiences and perspectives surrounding diagnosis comprehension. Findings revealed that participants did not receive clear explanations of their diagnoses of generalized anxiety disorder (GAD) and often had to seek understanding independently. Cultural and spiritual norms also shaped how participants interpreted their experiences and approached mental health care. The use of AAVE emerged as a culturally grounded means of expressing and making sense of these experiences. The results emphasize the importance of culturally responsive and linguistically inclusive communication to improve understanding, trust, and engagement among African American millennial women in clinical settings.Item Open Access Data-driven approach to evaluate fire risk for grassland prescribed burning management in the Great Plains Region(2025) George, MayowaPrescribed burning is a critical land management practice in the Great Plains of North America, helping to maintain native rangelands, reduce wildfire risk, and to facilitate favorable grazing. However, the Great Plains experienced approximately 498,000 wildfires between 1992 and 2020 which raised concerns about the effectiveness and safety of prescribed fire as a land management tool. Barriers to prescribed burning practice remain due to concerns on potential fire escape and fire danger. A localized fire danger index can help address these concerns by providing clear, science-based guidance, encouraging safer and confident use of prescribed fire. The Overall goal of this research is to develop a localized Grassland fire danger index through a data-driven modeling approach to support the planning and implementation of prescribed fire in the Great Plains. The specific research objectives of this dissertation include: (1) characterizing wildfire risks across the Great Plains using long-term historical records and climatic data to evaluate the spatial and temporal variability of fire activity and to identify key factors influencing wildfire occurrence; (2) developing user-friendly sub-models for dead fuel moisture content (DFMC) and grass curing, which serve as components of the proposed Grassland Fire Danger Index (GFDI), using localized meteorological and satellite data to represent mid-term and short-term drivers of fire potential. To characterize risks for wildfires risk in the Great Plains, this study analyzes wildfire records from 1992 to 2020 across the Great Plains states to assess spatiotemporal patterns in wildfire risk and evaluate the role of prescribed fires through combined analysis of wildfire data. Results show a threefold increase in both wildfire frequency and area burned, with fire size increasing from east to west and frequency rising from north to south. Wildfire seasons have gradually shifted earlier due to climate change. Drought severity accounted for 51% of the interannual variability in area burned, while grass curing accounted for 60% of the monthly variability of wildfires in grasslands. To develop user-friendly sub-models for DFMC and grass curing, which serve as components of the proposed GFDI, this study uses Oklahoma Mesonet weather data and satellite observations in a data-driven statistical approach. DFMC reflects short-term fuel moisture that affects ignition and fire spread, while grass curing represents seasonal drying that controls fuel availability. Both are critical for fire prediction and safe burns. Lower DFMC and higher grass curing levels are strongly associated with wildfire risks. The DFMC sub-model improves the accuracy and sensitivity of existing models. The grass curing sub-model shows that 50% curing usually occurs around April 15–16, which matches the time for the most intensive prescribed fire activities in the region, indicating it as a safe and effective window for prescribed fire recognized by landowners. The detailed findings from this research will lay a foundation for the development of a localized fire danger assessment tool that integrates long-term, mid-term, and short-term risk factors to improve prescribed fire planning and implementation in the Great Plains. The outcome of this study will assist land managers, fire professionals, and policymakers in making informed decisions for safer and more effective prescribed burning.Item Open Access Experimental evaluation of maximum debonding strain in thick CFRP layers for flexural strengthening(2025) Do, KhangCarbon fiber reinforced polymer (CFRP) is widely used for strengthening RC structures; however, the externally bonded reinforcement (EBR) method is often governed by premature debonding at the CFRP-concrete interface, preventing CFRP from reaching its full tensile capacity. Current design provisions limit the effective strain to control debonding, but most are based on test results conducted using thin CFRP layers, leaving uncertainties in their applicability to thick CFRP systems. This study investigated the maximum debonding strain, load-carrying capacity, and failure behavior of RC T-beams strengthened with multiple layers of thick CFRP sheets (V-Wrap C400HM) using the epoxy resin V-Wrap 770. The experimental program included ten RC Tbeams, which were divided into two groups: low-strength concrete (2.86 ksi) and normal strength concrete (4.44 ksi). Each group included a control beam, three beams strengthened with one to three thick CFRP layers, and one hybrid beam using an externally bonded reinforcement on grooves (EBROG) technique, where the soffit was pre-grooved and filled with epoxy putty before applying one thick CFRP layer. All specimen were tested under four-point bending, using displacement – controlled loading at a constant rate of 0.05 in/min. Experimental results showed significant strength enhancement with CFRP, with the peak performance observed in the two-layer systems, which provided the best strength – ductility balance. Specimens with three CFRP layers exhibited premature debonding or cover delamination, indicating a practical limit for effective CFRP thickness without additional mechanical anchorage. The hybrid grooved-putty configuration improved bond performance when applied in the normal strength concrete series compared to a single-layer externally bonded system. Among evaluated design guidelines, ACI 440.2R-23 provided most reliable prediction as compared to TR55, CNR-DT 200, fib-14, and JSCEItem Open Access Wildland fire risk quantification for prescribed fire management in the Great Plains(2025) Okafor, IzuchukwuWildfire activity in the Great Plains has increased over the past three decades. As a fire-dependent ecosystem, the region relies on prescribed fire to sustain the grassland structure, improve forage quality, support biodiversity, and reduce wildfire risk posed by antecedent fuel accumulation. Despite its ecological importance, prescribed fire application remains constrained by safety concerns and lack of tools for accurate fire risk assessment. Existing fire danger indices often focus on forests or have coarse spatial resolution, limiting their use for operational-scale grassland fire planning. This study quantified and modeled wildland fire risk in the Great Plains using historical local weather, fine fuel, and wildfire data from 1992 to 2020. A composite fire risk framework was developed, defining wildland fire risk as the product of seasonal and daily fire risks. The seasonal fire risk was estimated as the ratio of smoothed multi-year average daily burned area to the total land area and was modeled using multi-year average daily grass curing and multi-year average daily air temperature changes as predictors representing fuel phenology and climatic conditions, respectively. The seasonal fire risk model explained 97% of the variability in seasonal fire risk. Seasonal fire risk in the southern Flint Hills counties showed a bimodal pattern, with a primary peak in March and a secondary peak in October, covering 0.01% of the land area. In spring, seasonal fire risk decreases rapidly from its March peak of 0.034% of the land area. This decline coincides with the traditional April period for intensive prescribed burning, highlighting the importance of seasonal fire risk assessment. The daily fire risk was represented as the ratio of wildfire daily burned area to the smoothed multi-year average wildfire daily burned area, and was modeled using maximum sustained wind speed and dead fuel moisture as predictors. The daily fire risk was estimated as the ratio of wildfire daily burned area to the smoothed multi-year average wildfire daily burned area, and was modeled using maximum sustained wind speed and dead fuel moisture as predictors. The model explained 15% of the variability in daily fire risk. Analysis of wildland fire risk during the spring burn window (March 8 - May 8) over 15 years in the Flint Hills reveals that the quantified risk ranged from 0.005% to 0.088%, representing an approximately 18-fold difference in burning potential. Eleven days were found within the defined low-risk level (≤ 0.01%), during which optimal prescribed burning can be safely conducted, and 28 days were within the marginal range (0.01% - 0.18%), during which prescribed burning requires utmost caution. Spring’s peak seasonal risk (0.034%) was three times more than the fall seasonal risk peak (0.01%), which lies within the defined safe range of wildland fire risk. This pattern indicates that the fall season offers opportunities to implement prescribed burns at lower daily fire risk. The consistent distribution of fire size, frequency, and fuel characteristics across the Flint Hills offers an opportunity to generalize the framework prospectively across the Great Plains. These results provide a data-driven basis for selecting optimal prescribed burn days that consider fuel conditions and daily fire-weather variability. This approach establishes a foundation for continued efforts to develop localized decision-support tools for prescribed fire planning and wildfire management in the Great Plains.Item Open Access Effects of grain source and feed additive inclusion on processing characteristics and feeding value of swine diets(2025) Friesen, WalterA total of 7 experiments were conducted and structured in 3 chapters to evaluate the effects of grain sources and feed additive supplementation on feed processing characteristics, digestibility of energy and AA, and growth performance of growing pigs. For Chapter 1, two experiments were conducted to determine the effects of Kernza® grain on geometric mean diameter (dgw), Standard deviation (Sgw), angle of repose (AoR), and pellet durability index (PDI). Grinding characteristics were determined by changing hammermill screen hole diameters (2.0 mm, 2.8mm, 3.6mm), while pelleting characteristics were observed by increasing inclusion levels of Kernza® into treatments (0, 2.5, 5, 10, 30%). Increasing screen hole diameter increased dgw and decreased Sgw. Increasing Kernza grain from 0 to 30% of the diet improved PDI from 58.6% to 88.4%. For Chapter 2, two experiments were conducted to determine the effect of 3 sorghum varieties (red non-waxy, red waxy, white waxy) on dgw, Sgw, AoR, and PDI when ground with consistent hammermill settings (Exp.1), or to a consistent dgw of 550µm (Exp. 2). Waxy sorghum had greater dgw and PDI with a lower sgw , and AOR than that of the non-waxy sorghum and corn within Exp. 1. When comparing grain sources at a consistent particle size, waxy sorghum had a lower sgw leading to a more uniform product. Waxy red sorghum diets improved PDI compared to other grain sources. Chapter 3 encompassed three experiments to determine the impact of feed additive premix (FAP; proprietary blend of enzymes, prebiotics, plant extracts, and acidifiers) on energy metabolism, standardized ileal digestibility of AA, and growth performance when fed to pigs with varying diet compositions. Treatments were arranged with 2 levels of FAP (0.0, or 0.13%), and 3 diet types (corn-, sorghum-, sorghum & DDGS-based). Pigs fed corn and sorghum-based diets had similar growth performance and pigs fed sorghum and DDGS-based diets had reduced growth performance. The FAP used in this experiment did not improve growth performance of pigs and even reduced ADG of finishing pigs fed sorghum-based.Item Open Access Susceptibility of ruminant livestock to experimental infection with SARS-CoV-2 and HPAIV H5N1(2025) Cool, KonnerEmerging RNA viruses represent a constant and expanding threat to global public health, agriculture, and biosecurity. The recent panzootics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and highly pathogenic avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b illustrate how host-generalist viruses can infect a broad range of wildlife, companion, and food production animal species, sometimes sustaining transmission and spillover to humans. These events underscore the critical need to understand host susceptibility and potential transmission pathways early in an outbreak. The experiments described here were designed to investigate the susceptibility and transmission potential of ruminant hosts to SARS-CoV-2 and HPAIV H5N1 through controlled experimental infection studies. The objectives were to assess infection outcomes, viral shedding, within host virus competition, host adaptation, and potential animal-to-animal transmission following experimental exposure to each of these pathogens. The resulting data clarified the role of ruminant species in the respective pathogen ecology, reduced the uncertainty about undetected virus maintenance, and informed targeted surveillance and outbreak response. Collectively, these findings advanced our understanding of host range, intraspecies transmission, and the potential for these emerging zoonotic RNA viruses to establish new animal reservoirs.Item Open Access TABLE TALK Impact of Intergenerational food transmission on the nutritional environment and strategies for the prevention of eating disorders(2025) Meek, KathleenThis report examines the role of intergenerational food transmission in the prevention of eating disorders, emphasizing the influence of early feeding practices and family food environments on long-term relationships with food and body image. As rates of disordered eating continue to rise, this research highlights protective strategies rooted in nutrition science and developmental psychology, including shared family meals, responsive feeding using Satter’s Division of Responsibility, and parental modeling of intuitive eating. Through a comprehensive review of current literature, this report explores how food behaviors, attitudes, and language are passed down within families, often shaping a child’s internal regulation and self-perception. Particular attention is given to the impacts of weight-focused talk, food moralization, and restrictive feeding on emotional and physical health outcomes. Findings suggest that fostering autonomy at the table, eliminating shame-based messaging, and creating emotionally supportive food environments can reduce the risk of disordered eating and promote a lifelong, positive relationship with food. The research calls for more inclusive, longitudinal studies across diverse family structures, cultures, and socioeconomic contexts to better understand and apply these findings. This work positions food not just as sustenance, but as a vehicle for connection, identity, and emotional well-being. The research offers a framework for prevention that begins in the home and has the potential to shift generational narratives around eating and body trust.Item Open Access Families of students with exceptionalities: A phenomenological study of the lived experiences of families and public school discipline(2025) George, EmilyIn this study, I explored the lived experiences of eleven Kansas families navigating special education systems and disciplinary practices in public schools. I used a hermeneutic framework to interpret the meanings families ascribe to their advocacy, challenges, and resilience. Participants were limited to families of students with documented disabilities or exceptionalities who were enrolled in and received discipline from a Kansas public middle or high school. I collected data through semi-structured interviews in person and over Zoom and kept a researcher’s journal of my thoughts and responses during the entire research process. I cleaned the transcripts of the interviews and analyzed them using grounded theory approaches informed by Charmaz’s (2025) methodological guidance. I combed the transcripts twice to find recurring ideas, which I grouped into seven themes. Then, I read through the transcripts two more times to search for quotes that highlighted those themes and to check for outliers or discrepancies in my findings. Those findings revealed seven central themes: accessing services or supports, discipline and its effects on student wellbeing, family and school staff relationships, parental advocacy and agency, inequity and bias, familial strain, and informal growth and supports. All participant families described accessing services as a prolonged and continuous process that could be emotionally and financially exhausting. Inequity and systemic bias appeared in surprising ways, such as school staff using overt racial or ableist remarks or with academic performance used to deny formal services or accommodations and to perpetuate misinformation about child development. School staff used informal and formal discipline to promote safety and to discourage undesired behaviors. However, when discipline was exclusionary, it was stigmatizing and reinforced negative student self-perception, often increasing the behaviors the school attempted to decrease. Families reported behaviors being interpreted negatively, rather than being seen as communication or evidence of a skill deficit or underlying need. Teacher relationships emerged as pivotal: supportive educators were transformative influences that anchored the students in schooling, while punitive, traumatizing, or dismissive educators increased student disengagement, distrust of school staff, social isolation, and stress. Parental advocacy was a lifeline for student success, but also a burden, which left parents feeling misunderstood or marginalized. For some families, inequity and bias shaped daily school interactions, with race, disability, previous interactions with the district, academic standing, and narrow eligibility criteria influencing access to services and disciplinary outcomes. These systemic challenges encroached on the home and impacted family stress and dynamics, yet families also highlighted resilience and growth for their students through informal supports and affirming spaces, especially those within extracurricular activities. This study contributes to scholarship on family experiences in special education and public-school discipline through parent and student voices. The findings underscore the impact of school staff responses to and perceptions of students and the deleterious effects on student wellbeing when these are negative or punitive. While the participants mostly communicated neutral or negative experiences, the study findings also emphasize the transformative potential of supportive relationships. Implications for changes in practice include the need for consistent, individualized supports, trauma-informed and restorative disciplinary approaches, supported family-school partnerships, and an overall deeper understanding of students’, and their families’, experiences. In the conclusion, I recommend changes in school policy that highlight the importance of upholding the mandates of IDEA (Individuals with Disabilities Education Act, 2004), addressing the effects of exclusionary discipline, increasing access to information and supports, and strengthening the school-family-student relationship, especially for those students in need of support, such as those for whom the school issues a disciplinary action and those with disabilities or exceptionalities. Ultimately, this study calls for educational systems to move beyond deficit-based perceptions and toward practices that affirm the strengths and individuality of all students and their families.Item Open Access Evaluating U.S. Purity Culture’s Impact on Female Sexual Health and Development(2025) Pugh, Mary-JoyThe purpose of this research was to investigate the impact of Christian purity culture on the sexual health and development of emerging adult women in the United States. Using self-determination theory and social script theory, the research explores how exposure to purity culture and the internalization of Christian messages via identification and introjection impact sexual health outcomes, including functioning, guilt, pleasure, and first coital affect. The study also examines mediating and moderating variables including age and relationship status at the time of first intercourse. Using a mixed sample (N = 300) of college-attending and national panel participants, women aged 18-29 were asked to complete a retrospective online Qualtrics survey assessing exposure to purity culture, sexual health indicators, and religious internalization. Path analyses were conducted to test three hypotheses referencing the relationships among purity culture, religious internalization, and sexual health outcomes. Results indicated that exposure to purity culture beliefs in childhood is associated with poorer sexual health outcomes in emerging adult women, particularly when religious values are internalized through introjection rather than identification. Identification, while also associated with guilt, was positively associated with sexual pleasure, functioning, and older age at first intercourse, suggesting a buffering effect against the negative impacts of purity culture. Guilt was identified as a mediating factor in sexual health outcomes, and relationship status was found to moderate associations between purity culture and introjection, purity culture and guilt, and introjection and guilt. Findings contribute to a deeper understanding of how religious socialization and sexual scripts influence female sexual development and may inform future sexual education and mental health interventions. Ultimately, purity culture has a net negative influence on women’s sexual health outcomes, although the way its messages are internalized can mitigate the impact.Item Open Access The impact of effort on the search for information(2025) Payne, KarissaIn everyday environments, people encounter vast amounts of information but are limited in what they can realistically use in making decisions. Because acquiring information often requires effort, individuals may favor less demanding sources even at the expense of their accuracy. However, it remains unclear how effort costs and the predictive validity of information jointly shape information search in decision-making. This study investigates how these factors interact in probabilistic environments. Across two experiments, participants explored a two-dimensional digital environment, using their mouse cursor to uncover cue information used to predict answers in a two-alternative forced choice task. Cue predictive validities ranged from 50% to 100%, and effort was manipulated through cursor speed and cue distance. Experiment 1 tested how effort costs and predictive validity influenced sampling when validities were explicitly presented on screen, whereas Experiment 2 required participants to learn predictive validities through trial and error. In both experiments, higher effort reduced sampling of less valid cues, while perfectly predictive (100%) cues were consistently prioritized even under greater effort, demonstrating a certainty effect in information search. When predictive validities were hidden in Experiment 2, effort exerted a stronger deterrent effect than it did when predictive validities were known (Experiment 1), and individual variability in exploration strategies increased. Analyses further indicated that participants treated perfectly predictive cues as categorically distinct, and the functional form of effort’s influence was similar to that of a delay discounting curve. Together, these findings support a cost-benefit view of information search, in which people weigh expected information gain against the cost of effort. Effort constrains information sampling, but perfectly predictive information resists the cost of effort much more than less predictive information.Item Open Access Habitat and adaptive foraging impacts on the topology and conservation of plant-pollinator interaction networks(2025) Poyner, HeatherPlant-pollinator mutualistic interactions are crucial for maintaining global biodiversity. Therefore, it is important to identify the behaviors that confer stability to these communities by evaluating emergent patterns of community organization using network analysis for effective biodiversity conservation. In the U.S. Great Plains, habitat loss resulting from agricultural intensification has contributed to steep declines in pollinator populations. Private land conservation programs such as the Conservation Reserve Program (CRP) offer a potential solution to declining pollinator populations. However, most work has focused on bees with less effort to assess overall pollinator community structure in these conservation plantings. In addition to studying simple metrics of diversity, plant-pollinator network topology can provide insight into the behavior and ecological dynamics that structure these communities, such as adaptive foraging. Although theory has often implicitly assumed that plant-pollinator interactions are static, there is mounting evidence that pollinator species continually switch the plant species with which they interact to maximize energy gain per cost and enhance the efficiency of resource utilization. Pollinators may adapt their foraging choices to maximize mutualistic benefits or minimize competitive costs, but it is difficult to separate these influences on community structure and stability empirically. To address these issues, I performed empirical observations of plant-pollinator interactions on different CRP planting types as well as non-CRP grasslands and simulated plant-pollinator community dynamics with different adaptive foraging strategies. The objectives of this work were to: a) evaluate how local- and landscape-scale habitat characteristics influence the effectiveness of CRP planting types in supporting pollinator communities and b) examine how different adaptive foraging strategies and pollinator dependence on plants impact community stability and the resulting network topology in comparison to empirical networks. Pollinator community composition differed across CRP planting types, whereas pollinator abundance and diversity were more influenced by site-specific habitat characteristics, such as forb species richness and grassland habitat availability. Habitat characteristics had an interactive effect on pollinators such that landscape-scale habitat availability modulated the availability and diversity of pollinators that could use floral resources within CRP plantings. Plant-pollinator networks were specialized and modular, indicating that pollinator foraging decisions are guided more by niche partitioning in response to the abundance of competitors and the diversity of floral resources. In the simulation model, adaptive foraging resulted in less stable pollinator communities but larger pollinator populations, which suggests that without interaction switching interspecific competition kept pollinator populations at lower densities, but not so low as to result in competitive exclusion. Additionally, empirical network topology was most similar to that of simulated networks when pollinators were highly dependent on plants for survival. These findings offer insights into how the habitat characteristics of conservation plantings impact pollinator communities while highlighting the ecological dynamics that confer stability to plant-pollinator networks.Item Open Access Uncovering Hidden Patterns in Flight Safety Data Through Statistical Analysis(2025) Vandervort, MaxThis research aims to identify trends in data that indicate a potential increase in the risk of aviation accidents. By analyzing aviation incident historical data, we look at the relationship between incidents on the ground and those in flight, as well as minor incidents and major incidents within an Army aviation unit. Machine learning algorithms applied to data sets involving crew experience and mishap reports may determine whether indications exist that forecast a higher risk of an aviation incident for an aviation organization within the U.S. Army. Achieving zero preventable mishaps regarding aviation operations requires a proactive approach to hazard identification and risk management, which is explored in the methods of this project. The results from the analyzed data determine if any consistencies exist in the conditions within an aviation unit leading up to recordable mishaps.Item Open Access Diagnostic approaches to transboundary and zoonotic diseases(2025) Bold, DashzevegTransboundary animal diseases (TADs), including those caused by African swine fever virus (ASFV), Classical swine fever virus (CSFV), and Foot-and-mouth disease virus (FMDV), as well as highly contagious zoonotic agents such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), pose significant threats to agriculture and public health globally. Early detection and follow-up measures are critical for the management of these infectious diseases. In the laboratory, polymerase chain reaction (PCR) is the most commonly used method for diagnosing these pathogens; however, in order to rapidly identify and prevent the spread of these highly infectious viruses, point-of-care (POC) diagnostic assays for the detection of the pathogen’s genetic materials, antigens (Ag), and antibodies (Ab) in the field are necessary. In this dissertation, lateral flow assays (LFAs) for ASFV Ag and Ab detection, multi-antigen print immunoassays (MAPIAs) for ASFV and FMDV Ab detection, and indirect ELISAs for SARS-CoV-2 Ab detection were established. It was also demonstrated that POC approaches used in a low-income country were able to identify ASFV, CSFV, and FMDV genetic sequences in suspect materials, proving the feasibility of POC diagnostics for these pathogens in low resource environments. As a result of this thesis, valuable tools were generated for improving the detection and diagnosis of ASFV, CSFV, FMDV, and SARS-CoV-2.Item Embargo Evaluating the Efficacy of Nutrient Solution Reuse in Hydroponics(2025) Tetteh, MillicentNutrient solution reuse in hydroponics is a sustainable strategy to improve resource efficiency. However, increased microbial risks, nutrient toxicity, and accumulation of allelochemicals can compromise system safety and crop yield. The first objective of this study they are not specifically tailored to hydroponic nutrient solutions. This review synthesizes current knowledge on the risks and opportunities of nutrient reuse in hydroponic systems, highlighting emerging treatment technologies and the urgent need for hydroponics-specific, science-based standards to ensure both sustainability and food safety to support production by small scale farmers. In the second objective, we evaluated the combined performance of slow sand filtration (SSF), biochar filtration, and UV-C disinfection for multi-cycle reuse of hydroponic nutrient solution in romaine lettuce production and assessed the impact of treated nutrient solutions use of plant growth and nutritional quality. Results showed that SU (SSF + UV-C) and SBU (SSF + Biochar + UV-C) consistently achieved ≥5 log₁₀ reductions of E. coli, meeting World Health Organization (WHO) microbial safety criteria. Physically, turbidity remained <2 NTU, and SBU showed the highest light transmittance. Chemically, both treatments reduced ammonium-N, total N, and total P, with SBU showing the highest removals. However, nitrate levels remained relatively stable, calcium steadily accumulated across cycles, and pH in SU and C fell below Food and Agriculture Organization (FAO)/World Health Organization (WHO) guidelines. Micronutrient analysis revealed substantial declines in Fe, Zn, Cu, and Mn—up to 90–97% in SBU resulting in progressive micronutrient imbalance despite EC-based nutrient supplementation. Romaine lettuce grown in SU initially produced the highest biomass but declined by ~30% across cycles, while SBU showed even larger reductions (~45%). Chlorophyll, SPAD, and vitamin C decreased in all treatments, reflecting micronutrient depletion, salinity stress, and oxidative damage. The freshwater treatment also experienced reduced quality due to ammonium accumulation. Overall, combining SSF, biochar, and UV-C provides effective microbial inactivation and maintains physical water quality but progressively depletes essential micronutrients, limiting long-term crop performance. These findings highlight the potential of low-cost treatment systems for small-scale hydroponic growers while emphasizing the need for cycle-specific micronutrient supplementation to sustain yield and nutritional quality during extended nutrient-solution reuse.Item Open Access Fed Cattle Basis Risk under Grid Pricing(2025) Alderson, CaitlynHedging risk in fed cattle markets has become increasingly important as producers face elevated price volatility and market uncertainty. This challenge is particularly pronounced for producers marketing cattle using grid pricing systems, which reward or penalize producers based on carcass attributes such as yield grade, quality grade, and carcass weight. Grid pricing has expanded rapidly over the last decade to represent about 70% of fed cattle marketings. Despite its prominence, little is known about how basis risk changes when cattle are priced using grids instead of traditional live or dressed pricing. With more variable factors impacting realized net price, we expect basis risk increases when cattle are sold on a grid. While grid pricing offers opportunities to capture premiums for higher-quality cattle, it also exposes producers to downside risk due to discounts applied to cattle that do not meet desired specifications. Managing this dual exposure to both price and quality-related premium/discount risks requires quantifying the price risk managed through traditional live or dressed price hedging. It also involves understanding the risk that remains due to varying cattle quality and associated grid component value variation. Results will inform producers using grid pricing of unhedgeable risk using traditional price risk management tools of futures and Livestock Risk Protection. Depending on the magnitude of elevated price risk, additional price risk management instruments might be warranted to manage price risk more effectively. For example, developing a Choice-Select spread or other price risk management market may be valuable. The objectives of this thesis are to quantify how fed cattle hedging risk has changed and to identify the main determinants of hedging risk for grid-priced fed cattle. A key measure is basis risk, the difference between the realized and predicted basis under various fed cattle valuation systems, and the uncertainty of cattle quality. Unique to this study is the adjustment of the predicted basis based on how cattle are priced and the expected quality distributions of cattle of varying quality and premiums/discounts, providing an essential contribution to better understanding contemporary fed cattle basis risk. Hedging risk changes as uncertainty on cattle quality and premiums and discounts are introduced: 1. We start by quantifying traditional weekly basis risk for cash-negotiated cattle over 20 years (2005-2024). This provides a baseline to illustrate historical trends and the evolution of basis risk. 2. Next, risk is quantified on a weekly basis for constant cattle quality (used broadly here to include quality grades, yield grades, carcass weights, etc.), letting premiums and discounts vary over time. Constant carcass quality distributions are averages based on more than 10,000 pens of packing plant grid carcass data obtained from commercial feedyards. This step enables us to determine how introducing varying premiums and discounts affects traditional hedging risk. 3. The analysis then incorporates quality and premium variability over time assuming producers have perfect foresight of quality of each pen hedged. To accomplish this analysis, a random pen of cattle is selected each week from the commercial feedyard data noted above. In this way, quality variation is introduced, but since it is assumed that the producer perfectly anticipates the quality of each pen, there is no quality uncertainty. This segment enables incremental measurement relative to the previous scenario of how introducing quality variation impacts hedging risk and premium/discount variation over time. 4. Finally, imperfect quality guesses are introduced by adding random errors to predicted quality distributions based on the above-referenced feedyard data. This segment enables incremental variation from above scenarios adding quality uncertainty. My approach highlights increasing complexity and variability in basis risk as grid pricing systems dominate the market. Understanding this complexity is critical for producers because it directly impacts the effectiveness of traditional risk management tools. Producers, policymakers, and market participants must recognize these dynamics to develop innovative tools and strategies that better address the unique risks posed by grid pricing. Price risk management in fed cattle markets is of greater importance than ever, with high price levels and elevated price risk. However, traditional hedging instruments are designed for hedging commodity cattle sold using negotiated cash prices. However, with grid pricing, valuing cattle based on carcass merit has become the dominant fed cattle valuation method, and the basis risk for cattle hedging is poorly understood. Traditional hedging instruments enable only base price protection but do nothing to manage varying premiums and discounts on uncertain cattle carcass quality. This study will demonstrate how basis risk changes as cattle are grid-priced and quantify the amount of price risk unhedged for grid-valued cattle. The study will also explain how much of this variation is due to premium/discount variation and uncertainty about varying cattle quality. The findings will provide critical insights for evolving price risk management tools for cattle producers and inform policymakers in designing LRP risk management programs. Depending on the extent of unhedgeable risk identified, new price risk management tools or institutions may be needed to mitigate the increasing price risk associated with grid pricing.Item Embargo Modifying Functional and Nutritional Properties of Pulse Flours and Starches by Roller Milling and Thermal Processes(2025) Qi, JingFunctional and nutritional properties of pulse flours and starches were enhanced by controlled roller milling and thermal processes, with an emphasis on increasing resistant starch (RS) content and understanding factors that influence starch digestibility. In Chapter 1, a comprehensive review highlighted the nutritional significance of pulses, particularly dry peas, lentils, and chickpeas, which are rich in dietary fiber, slowly digestible starch (SDS), and RS. This chapter discussed how pulse-based ingredients, especially flours, can be strategically used in food applications to reduce glycemic response and enhance satiety. In Chapter 2, the molecular structure of pea starch was analyzed, and its amylose content was measured by four methods and compared with starches from maize, potato, and high amylose maize. Pea starch had ~38–40% amylose content as measured by iodine colorimetric, differential scanning calorimetry (DSC), and gel-permeation method (GPC) methods. The Concanavalin A method yielded a lower value (30.4%), suggesting the presence of clustered short branches in pea amylose. The findings highlight the importance of method selection in characterizing starch structure. Given their high amylose content, pea and high amylose maize starches were selected for the production of starch spherulites. In Chapter 3, DSC and a Parr reactor were used to investigate spherulite formation. Spherical crystalline aggregates, known as starch spherulites, were successfully formed from both starches through a controlled thermal process involving heating followed by controlled cooling. Under optimized conditions, both pea and high amylose maize starches formed B-type crystalline spherulites, highlighting the potential for scalable production and future applications in targeted nutrient delivery. In Chapter 4, dry roller milling was used to generate pulse flours from yellow peas, chickpeas, and lentils with varying cell wall integrity. Coarse-sized flours retained more intact cotyledon cell walls, leading to significantly reduced starch digestibility and higher RS levels, particularly after cooking. Chapter 5 focused on the thermal properties of dehulled pulse flours at different moisture levels using DSC. Distinct thermal behavior was observed among the flours and their components (isolated starch, protein fractions), providing fundamental knowledge for the hydration-dependent functional performance of pulse ingredients. In Chapter 6, a novel heat moisture treatment (HMT) protocol was developed and applied to pulse flours to enhance their structural and nutritional qualities. HMT led to increased RS and total dietary fiber content, altered thermal transitions, and reinforced starch crystallinity, demonstrating its potential to improve starch-protein interactions and enzymatic resistance. Chapter 7 summarized the overall conclusions and future research directions. Overall, this dissertation integrates molecular analysis, starch crystallization, flour processing, and thermal/digestibility profiling across seven chapters, advancing the understanding of how pulse starch and flour properties can be optimized for nutritional and functional applications.Item Open Access Community economic development in two rural Kansas communities: a thematic analysis(2025) Colle, KevinRural communities across Kansas face growing challenges of population decline, limited financial resources, and shifting economic structures. This study examines the factors that shape community economic development (CED) in two rural Kansas towns, Sterling and Nickerson, using the Community Capitals Framework (CCF) as an analytical lens. The CCF identifies seven interrelated forms of capital that collectively influence a community’s development trajectory. Through a qualitative comparative case study approach, nine semi-structured interviews were conducted with local leaders and stakeholders from both communities. Data were coded deductively using the seven capitals and analyzed inductively through thematic analysis. Findings reveal four interrelated themes shaping CED in these communities: (1) the power and limits of social capital, (2) political capital as a gatekeeper to development, (3) identity and attachment to place, and (4) built strengths and constraints. The study concludes that communities with well-coordinated political, social, built, and cultural capitals are more likely to “spiral up” toward sustainable growth, while those with fragmented or exclusionary networks risk “spiraling down.” By applying the CCF to rural Kansas, this study contributes to the understanding of how small towns mobilize their assets amid structural and demographic challenges. The findings offer insights for policymakers, local leaders, and development practitioners seeking to strengthen community resilience and guide equitable economic growth in rural America.Item Open Access Free choice feeding and its impact on feed efficiency and oxidative stress in growing sheep(2025) Frey, JonnThe traditional total mixed ration (TMR) is a staple in the animal feeding industry as it allows, on aggregate, for animals to perform at a high level of efficiency when feeding large numbers of animals together. However, free choice feeding could have performance benefits and help improve the well-being of animals compared to TMR feeding that is used today. With free choice feeding, animals can develop and exercise individual preference of feedstuffs which has been theorized as one potential reason for the improvement in efficiency with free choice feeding. We conducted a study using growing sheep to assess differences in performance and oxidative stress between the two feeding methods. For this study, Polypay lambs (n=23, BW = 29.7 ± 6.6 kg) were utilized with lambs being blocked by body weight and randomly assigned to either a TMR diet (CON) or a free choice diet (FCD). The diets for both TMR and the FCD were of the same primary ingredients, with the free choice group having the macro nutrients (energy and protein) being supplied by the two main components of the TMR, corn and alfalfa, offered separately in pelleted form. For determination of the oxidative health impact of the two feeding systems, blood was collected at the beginning and end of the experiment, and was analyzed for the oxidative stress metabolite malonaldehyde (MDA) and the overall antioxidant capacity (AO). The experiment lasted a total of 42 days. Lambs were fed daily with the refusals targeting 5% to allow for ad libitum consumption. Lambs were weighed weekly for the duration of the experiment and rate of gain was determined using linear regression, with the slope of the regression line being average daily gain (ADG). The heavy block of FCD had a greater (P <0.05) ADG compared to the heavy block of CON (0.23 kg/d vs 0.17 kg/d), but was similar to light blocks of the FCD and CON treatments. For DMI, TDN intake, and the variability of daily intake, there was no significant difference between treatments for any of these variables. For F:G, although no difference was observed between treatments, a significant treatment by block interaction was observed (P = 0.04). Intake of CP was a greater (P = 0.03) for CON than for FCD (0.31 kg/d vs. 0.26 kg/d). Sheep in the FCD group showed an initial preference for the alfalfa pellets, but they began to prefer corn relative to alfalfa as the experiment progressed. Measures of oxidative stress showed no differences between treatment groups at the start as well as the end of the experiment. The results of this study showed that, although some benefits to animal performance might occur with FCD, the positive impact on oxidative stress may not be true in all situations, in contrast with previously published literature.
