University of Tennessee Institute of Agriculture
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Cost Sensitivity to Radiological Soil Release Criteria in Decontamination and Decommissioning Projects
No full textThe linear no-threshold (LNT) hypothesis and the ALARA (as low as reasonably achievable) principle are fundamental to setting release criteria for Decontamination and Decommissioning (D&D) projects. The LNT model assumes that any radiation dose, no matter how small, increases health risks, such as cancer, in a linear, proportional manner without a safe threshold. This can lead to selection of release criteria that are more stringent than federal requirements, potentially driving up project costs. This research presents a method to quantify the impact of lower release criteria on the relative cost of soil remediation and final status surveys (FSS).
Using Python scripts, a methodology was developed that uses existing radiological characterization data to calculate total contaminated soil volumes and surface areas for a range of release criteria. Unit cost factors for both soil remediation and FSS were then applied to these calculations. The remediation unit costs were based on a previous license termination plan\u27s ALARA analysis and the FSS unit costs were derived using the MARSSIM methodology and available characterization data.
This methodology was tested on two case studies: the Rocky Flats Plant and the former Hematite fuel fabrication facility. The results show a power-function relationship where costs increase significantly as release criteria are lowered. Costs were normalized to a 0.25 mSv/y release criterion and compared with historical estimates identified in a Government Accountability Office report. The Rocky Flats case study demonstrated a more sensitive, inversely proportional cost response to reductions in the release criterion, consistent with previous estimates for the Nevada Test Site. The Hematite facility showed a less sensitive but still significant cost escalation.
These case studies illustrate a clear, direct relationship between project cost and the selected release criterion. The model developed can serve as a valuable tool for stakeholders to scope the relative costs of soil remediation and FSS for future D&D projects
ANALYZING ADVANCED COMPOSITE SHIELD MATERIALS FOR FUSION AND SPACE REACTOR APPLICATIONS
No full textTwo feasibility issues associated with high performance composite radiation shields for nuclear energy systems were investigated. The first research thrust involved identification of sintering aids for reducing the sintering temperature of HfH2-ceramic matrix in order to suppress hydrogen dissociative loss from the HfH2 particles during consolidation. The second research thrust involved quantification of the impact of uniformly distributed incoherent hydride particles on the effective diffusion, solubility and permeability of hydrogen isotopes of composite radiation shields.
LiF was chosen as a sintering aid for ZrN and MgO ceramic matrix powders to investigate whether sintering enhancement could be achieved during spark plasma sintering (SPS). LiF additions up to 2%wt did not affect SPS sintering for ZrN whereas a strong reduction in sintering temperature occurred for MgO. The mechanisms responsible for the difference in sintering behavior of these two ceramics were investigated by modeling and advanced characterization techniques. The conventional hypothesis of enhanced consolidation due to LiF liquid phase sintering appears to be invalid since LiF doping did not result in sintering temperature reduction in ZrN, and did not strongly affect MgO sintering above and below the LiF melting temperature. An alternative mechanism is proposed based on enhanced self-diffusion due to creation of Schottky vacancies by the monovalent LiF dopant in the divalent ceramic matrix. Differences in effectiveness of LiF doping for MgO vs. ZrN are attributed to much lower LiF solubility in ZrN, with a corresponding reduction inSchottky vacancy production.
Hydrogen isotope permeation measurements on sintered MgO and metal matrix composite Fe-HfH2 samples were obtained. The results were compared with model predictions considering H permeation in the metal or ceramic matrix and trapping of diffusing H isotopes at the incoherent particle-matrix interfaces of the distributed HfH2 particles that can produce significant increases in effective solubility and decreases in effective diffusivity, with a resultant increase in effective permeability at low temperatures. An interfacial trap binding energy for H isotopes of ~1 eV and incoherent interface trap thickness of ~1% the matrix lattice plane spacing provided reasonable agreement between experimental measurement and model predictions of effective diffusivity and permeability in the composite
COLLABORATIVE ONLINE LEARNING MEDIATED THROUGH CONCURRENT UPDATE TECHNOLOGY IN ASYNCHRONOUS AND SYNCHRONOUS ENVIRONMENTS
No full textThis dissertation investigates how collaborative modality (asynchronous versus synchronous) and collaborative technology (standard tools versus concurrent update tools) affect academic performance, perceived learning outcomes, and collaborative experiences in fully online higher education. Grounded in the Theory of Transactional Distance, the Community of Inquiry framework, and Social Presence Theory, the research addresses gaps in understanding how technology and instructional modality interact to shape collaboration when instructional content, assessments, and group tasks are held constant. Using a quasi-experimental 2×2 factorial design, undergraduate business students (n = 242) completed two small-group collaboration assignments in one of four conditions: asynchronous standard, asynchronous concurrent, synchronous standard, or synchronous concurrent. Data sources included objective performance scores, post-assignment surveys measuring perceptions of academic performance and collaborative experience, and demographic information. Analyses using ANOVA, Welch’s ANOVA, Games-Howell post hoc tests, and independent samples t-tests revealed that concurrent update tools were consistently associated with higher academic performance, particularly in asynchronous conditions, and with improved perceptions of group functioning, structure, and tool support. Synchronous conditions supported greater trust, affective connection, and engagement, while asynchronous concurrent conditions demonstrated notable performance advantages. Results indicate that neither collaboration alone nor concurrent update technology in isolation consistently improved outcomes; the most substantial benefits occurred when iii collaborative activities were purposefully structured and paired with concurrent update tools aligned with task demands and learning objectives. These findings refine and extend existing theoretical frameworks by showing how co-editing platforms can bridge structure, presence, and learner interaction across modalities. Practical implications include designing intentional collaborative activities supported by real-time tools in both synchronous and asynchronous environments, alongside institutional investments in platform access, student training, and learning management system integration. By centering both outcomes and the processes that shape collaboration, this dissertation advances empirical and theoretical understanding of technology-mediated collaboration in online higher education and offers actionable strategies for creating equitable, engaging, and effective digital learning environments
Rapid and Sensitive Molecular Detection Tools for Oak wilt and Laurel Wilt Pathogen and Comparative Transcriptomics of Oak Wilt Hosts
No full textVascular wilt diseases caused by fungal pathogens represent major threats to forest health and agricultural systems across North America. Laurel wilt, caused by Harringtonia lauricola and vectored primarily by the redbay ambrosia beetle, has led to extensive mortality of Lauraceae species in the southeastern United States (US) and poses a significant risk to avocado production in Florida. Oak wilt, caused by Bretziella fagacearum, continues to spread through central and eastern regions of the United States, killing red oaks (Quercus rubra) within weeks of infection while white oaks (Q. alba) exhibit partial resistance. A critical challenge common to both diseases is the difficulty of detecting fungal DNA during early or low-titer infection, especially in host tissues or insect vectors.
To overcome these limitations, we developed highly sensitive, species-specific detection assays targeting informative SSR regions: the IFW TaqMan probe for H. lauricola and the BF45 TaqMan probe for B. fagacearum. Both probes function with gold standard quantitative PCR (qPCR) and conventional PCR systems. Using a simple blue-light flashlight visualization method, fluorescence in amplified products can be interpreted without specialized equipment or technical expertise. Detection limits achieved by qPCR were 0.32 pg/µL for H. lauricola and 0.008 ng/µL for B. fagacearum, while conventional PCR combined with blue-light detection identified 0.008 ng/µL and 0.04 ng/µL, respectively. Validation using symptomatic host tissue and insect vectors confirmed the robustness of these assays for early-stage diagnosis and field-oriented surveillance.
We also investigated the molecular basis underlying the differential susceptibility of oak species to B. fagacearum through a time-course RNA-seq experiment comparing Q. rubra and Q. alba following controlled inoculation. Transcriptomic profiles revealed that Q. alba rapidly transitions from growth to defense, activating salicylic acid and reactive oxygen signaling, reinforcing cell walls, and inducing vessel-occluding defenses. In contrast, Q. rubra displayed strong early perception and detoxification signaling but weaker downstream defense integration, suggesting a temporal mismatch that contributes to systemic fungal spread and rapid mortality. Together, these studies deliver practical, low-cost diagnostic tools and provide new insight into host defense dynamics. The sensitive detection assays and molecular understanding of disease response will support monitoring, management, and resistance-based strategies for laurel wilt and oak wilt
Unravelling Chemical Bond Exchange Pathways in Polyester-based Vitrimers and its Composites
No full textPolymers and their composites are ubiquitous materials with applications across a broad range of sectors, including automotive, aerospace, biomedical, and construction industries. Despite their technological significance, conventional polymers face persistent challenges related to sustainability, recyclability, and multifunctionality. To address these limitations, vitrimers, a new class of polymeric materials possessing covalently adaptive networks (CANs) have emerged as promising candidates that bridge the gap between thermosets and thermoplastics. Vitrimers combine the mechanical robustness and thermal stability of thermosets with the reprocessability, repairability, and recyclability typical of thermoplastics, offering a transformative pathway toward circular materials design. However, their industrial adoption remains limited due to an incomplete understanding of the molecular parameters governing bond-exchange dynamics and network relaxation behavior.
This dissertation aims to elucidate the molecular-level mechanisms controlling relaxation dynamics in polyester-based vitrimer systems engineered for scalable manufacturing. A fast-relaxing vitrimer matrix was designed by incorporating dynamic ester linkages between rigid aromatic precursors (hard segments) and soft, rubbery components (soft segments), forming a dual-phase architecture that exhibits high mechanical toughness and robustness due to the rigid domains, while enabling rapid reprocessability and recyclability upon thermal activation via the flexible segments. The dynamic ester-based functionalities of this vitrimer matrix were further exploited to fabricate hierarchically structured fiber-reinforced composites (FRCs) that demonstrate exceptional mechanical strength and closed-loop recyclability, driven by reversible covalent interactions between hydroxyl-rich fibers and the vitrimeric ester matrix. To develop a comprehensive understanding of relaxation dynamics beyond chemical exchange phenomena, model systems were synthesized to isolate and analyze key parameters such as crosslink density, spatial bond orientation, and proximity of exchangeable sites. Furthermore, novel non-invasive spectroscopic methodologies, including low-field NMR and AFM-based nanoIR, were developed to accurately determine the topology freezing temperature (Tv) in vitrimers, effectively decoupling chemical bond exchange dynamics from local segmental motion.
The findings presented herein aim to advance fundamental understanding of molecular determinants governing bond-exchange and relaxation dynamics in ester-based vitrimer systems. These insights not only inform the rational design of vitrimer networks with tunable processability and performance but also provide guiding principles for scalable manufacturing of next-generation recyclable and repairable polymer composites
Interdisciplinary and Cross-Disciplinary Collaborations in Counselor Education and Supervision
No full textInterdisciplinary research has exponentially developed in response to federal funding opportunities, more complex needs in the community, and program expansion within schools. Given the counseling profession’s unique qualities, counselor education and supervision researchers can elicit robust platforms to cement counselors as key collaborators in community-based interventions, public health initiatives, and large-scale programs. Bringing together a collection of five articles, this special issue focuses on interdisciplinary and cross-disciplinary collaborations in counselor education and supervision
Recognizing Cognitive Decline in the Rural Communities: An Initiative to Improve Cognitive Screening in Adults less than 65 years old in Rural Areas
Get PDFBACKGROUND: Cognitive impairment is much higher in rural areas than in urban locations. With a rapidly aging population, multiple healthcare disparities, and increasing healthcare costs, there is a critical need to implement earlier detection of cognitive decline in rural communities. Cognitive Screenings in primary care clinics show benefits through patient outcomes and have cost-effective benefits. Healthy People 2030 aims to increase the percentage of adults aged 45 and older who have confusion and memory loss and report these findings to their healthcare provider to 50.4 %.
LOCAL PROBLEM: The setting of this practice improvement project was a rural primary care clinic in Western North Carolina. There was no standardized screening process for adults ages 40-64 in this primary care setting. The purpose of the project was to standardize a screening process in the primary care setting for patients ages 40-64 at the annual visits.
METHODS: The Evidence-based Practice Improvement model provided a framework for project implementation. The clinical workflow for administering the cognitive tool was determined through PDSA (Plan-Do-Study-Act) cycles. Implementation data were measured to evaluate the screening process and compliance.
INTERVENTIONS: An educational session was conducted before the implementation of the screening process. Weekly training was provided to the clinic staff during implementation with email follow-ups to providers on the screening rates and positive screenings.
RESULTS: There were a total of 124 annual visits completed and 110 mini-cog screenings completed. This resulted in an average of 89% screening rate overall, 13% of those found to be positive for cognitive impairment, 100% were scheduled for follow up.
CONCLUSION: Implementing a standardized brief screening tool for adults aged 40-64 adults had a clinically significant impact on the detection of early cognitive decline. Sustainability plans include utilizing the electronic health record to incorporate alerts for screenings and follow-up
