Digital Commons Network^™

Design And Development Of Evacuated Photovoltaic-Thermal Systems For Efficient Cogeneration Of Heat And Electricity, Behnam Roshanzadeh

Mechanical Engineering ETDs

In conventional PV systems, most of the solar energy is dissipated into the environment as heat. Accordingly, hybrid Photovoltaic-thermal systems have been developed to utilize the waste heat from PV cells for various thermal applications. However, most PVT systems suffer from low thermal performance compared to solar thermal collectors, as the absorber plate in PVT systems is partially or fully covered by PV cells. This dissertation focuses on improving the thermal performance of PVT systems by introducing the evacuated PVT systems.

An evacuated-tube PVT system was designed and simulated for domestic hot water supply. The evacuated-tube PVT system demonstrated 40% …

Dense Temporary Array Investigation Of Jemez Uplift Seismicity, Jillian D. Podmore

Earth and Planetary Sciences ETDs

A protracted multi-stage tectonic and magmatic evolution combined with low regional crustal strain rates make it challenging to characterize active structure that may host earthquakes in the Jemez Mountains of New Mexico. Here, we leverage temporary 1-month deployments of nodal seismometers to gain new insights into seismicity of the Jemez Mountains, which only have continuous seismic monitoring on their eastern flank as a result of the Los Alamos Seismic Network. Our catalog is built using 4 steps: phase picking in continuous seismic data, association of picks to detect unique events, event magnitude estimation, and absolute hypocenter estimation. We detect and …

Seismological Investigations Of Magmatic Systems Using Dense Nodal Arrays, Wenkai Song

Earth and Planetary Sciences ETDs

Understanding the internal architecture of magmatic systems is crucial for volcanology, yet conventional geophysical techniques often lack the resolution to image their fine-scale structures. This dissertation leverages unique datasets from dense nodal arrays to investigate the upper crustal magmatic systems beneath Yellowstone Caldera, Valles Caldera, and Mount St. Helens. At Yellowstone, I processed vibroseis data to delineate the top of the modern magma reservoir and evaluate the thermal connection between the magmatic and the overlying hydrothermal systems. At Valles, 3D radial seismic anisotropy imaging reveals strong positive radial anisotropy within the reservoir, indicating an organized structure of horizontally sill-like melt …

Application Of Bimetallic Transition Metal Oxides Electrocatalysts For Li-Co2 Batteries And Li-O2 Batteries, Jianda Wang

Chemical and Biological Engineering ETDs

Li-ion batteries are the dominant commercial rechargeable batteries nowadays, which are used in electronic devices and electrified transportation widely. However, undesirable energy density of Li-ion batteries prohibits them from meeting requirements of new generation electronic devices. Therefore, it is important to find more alternative electronic energy storage systems with higher capacity. Fortunately, Li-CO2 batteries, featured high capacity and ability to convert CO2, have become a promising candidate to replace Li-ion batteries. In addition, Li-O2 batteries also attract people’s attention due to their high energy density and low cost. However, Li-CO2 batteries and Li-O2 batteries both face challenges of terrible cycle …

Physical Education Through The Lens Of A Transgender Individual, Allison L. Graham

Health, Exercise, and Sports Sciences ETDs

Transgender students face unique challenges in K–12 physical education (PE) that other groups of students do not experience. The purpose of this qualitative study was to explore the life history of a transgender woman, Evergreen, with a focus on her experiences in PE throughout K-12 school. This study was guided by Queer Theory (Jagose, 1996) and Atkinson’s (1998) life history methodology, data was collected through nine semi-structured interviews and participant-selected artifacts. Data was analyzed using Merriam and Tisdell’s (2016) coding procedures to identify themes. Findings revealed distinct experiences across four areas: (1) Elementary School PE—positive memories centered on play …

Predicting The Unpredictable: Advancing Risk Management In Fitness Centers Through Data Science-Driven Judicial Outcome Modeling, Hongyoung Kim

Health, Exercise, and Sports Sciences ETDs

This study developed a prediction model of judicial outcomes in fitness exercise-related injury lawsuits to identify key factors influencing fitness centers’ success in litigation. Using 209 U.S. court cases from Westlaw, Phase One employed text mining and content analysis to identify legal variables. Phase Two applied descriptive statistics and multiple logistic regression to evaluate the combined influence of these variables on judicial outcomes. For the multiple logistic regression analysis, the sample size was reduced to 184 cases after excluding 25 remanded cases.

Results showed that victim behavior, hazardous facility conditions, and enforceable waivers or exculpatory clause defenses significantly predicted judicial …

Analysis Of Heat Transfer And Pressure Drops Associated With Twisted Tube Heat Exchangers, Braden Foderaro

Nuclear Engineering ETDs

Several studies have been done on the effects of twisted tubes in heat exchangers, including the correlations that relate the flow parameters to the heat transfer and pressure drop experienced. These studies are new, with the earliest being performed in 1982. As such, there are many correlations covering only certain flow parameters and geometrical configurations such as the Reynolds number and modified Froude number.

This thesis attempts to cover flow regimes and tube geometries not yet studied and yield correlations. Data are gathered from heat exchangers featuring twisted tubes with water as the working fluid. It is noticed that the …

Non-Destructive Characterization Of Ion Irradiated Yttrium Hydride For Microreactor Applications, Ryan E. Pena

Nuclear Engineering ETDs

As energy demands increase, nuclear reactors, especially microreactors, become a promising energy source. These reactors run at high temperatures (>280°C), requiring moderators that can endure these environments. Yttrium hydride is a possible moderator, but little is known about the material’s phase stability and hydrogen retention under irradiation. Through the use of a gold ion beam, samples with stoichiometries ranging from 1.6 to 2.0 were irradiated and tested. Through Vickers hardness testing, a model was created showing a correlation between hydrogen content and hardness. Raman spectroscopy showed high temperature and irradiated samples have significant hydrogen loss. XRD quantified this hydrogen …

Sequential Low Dose Proton Irradiation And Nanomechanical Testing To Understand Mechanical And Microstructural Property Changes In Alloy 709, Abhishek Kc

Nuclear Engineering ETDs

Alloy 709, a 20Cr25Ni alloy, is an advanced austenitic steel designed for next generation sodium fast reactors. Preliminary studies have shown the potential of Alloy 709 in sodium fast reactors. In this study, Precipitate Treated Alloy 709 specimens are irradiated with 2 MeV H⁺ at 500 °C from 0.0057 dpa to 1.7 dpa. Electron microscopy characterization techniques are used to understand the effects of radiation on mechanical properties as well as microstructure of Alloy 709. The microstructure did not show formation of voids, amorphization of precipitates, or increase in grain size up to 1.7 dpa. Correspondingly nano-indentation and micro-pillar …

Coupled Adjoint-Based Perturbation Theory For Dynamics And Heat Transfer Multiphysics For Nuclear Transients, Alexis Maldonado

Nuclear Engineering ETDs

Nuclear reactor multiphysics modeling and simulation (M&S) enable advanced reactor design by analyzing how systems will react over time to various configurations, scenarios, and perturbations. However, high-fidelity coupled transient M&S for reactor cores are computationally expensive, making robust analyses challenging. This work develops a Coupled Adjoint-based Perturbation Theory for dynAmIcs and heat traNsfer (CAPTAIN) framework to rapidly quantify the impact of uncertainty to overall transient responses by generating sensitivity coefficients for temperature, power, and delayed neutron precursor concentrations using forward and adjoint solutions. This work presents an initial proof of principle, verified with direct perturbations to several inputs. Furthermore, this …

A Risk-Informed Approach To Performing The Pre-Closure Safety Analysis For The Deep Borehole Disposal Of Radioactive Waste, Jennifer Elizabeth Leute

Nuclear Engineering ETDs

Deep borehole disposal is an emerging concept which involves disposing of radioactive

waste in boreholes several kilometers deep then backfilling to minimize radionuclide

transport and distribute weight. Unfortunately, little documentation exists on borehole

safety case development, especially for pre-closure operations. This study aims to close

this gap by proposing a graded approach matrix based on consequence, maturity, and

complexity. Two case studies are used to demonstrate this application: Hanford CsCl

capsules and spent PWR assemblies. Simulations are used to predict potential for dose

exposure, revealing CsCl capsules have a much higher potential for being above the 5

rem public dose …

Kakeya Sets Over The Heisenberg Group, Gabriel Jacob Gress

Mathematics & Statistics ETDs

The Hausdorff dimension of Kakeya sets is an interesting problem where the two-dimensional case can be proven directly, but even obtaining bounds on the higher dimension analogues can require highly technical machinery. The difficulty of the general case has inspired analysts to look at Kakeya sets from non-Euclidean viewpoints.

In this paper, we explore a construction of the Kakeya set in the first Heisenberg group H^1. By utilizing the sub-Riemannian manifold of H^1 we can apply tools in geometric measure theory which at this time cannot be applied in R^3. We restate and provide a detailed proof for a sharp …

On Sharpest Tail Bounds For Functions Of Tail Bounded Random Variables, Stephen Harrison

Mathematics & Statistics ETDs

Consider n real/complex, independent/dependent random variables with respective tail bounds and g a measurable function of the r.v.’s. Consider f the “sharpest” tail bound of g (sharpest in the sense, if f were any less, then for some X1, ..., Xn satisfying the conditions, g(X1, ..., Xn) would not satisfy the tail f). Significant research has been done to approximate f often with high accuracy. These results are often of the form, for g in this family, and tail bounds of Xk in this family, f is bounded by some f′ with high accuracy. However, the question “what would it …

Improvising Across Abilities: Pauline Oliveros And The Adaptive Use Musical Instrument [Book Review], Maria A. Souliotis

Disability in LIS (DisLIS)

This book reviews how the AUMI movement has evolved in the years since its inception, with the people involved in it most closely detailing its impact on music education and disability activism. Narratives, case studies, and personal reflections highlight Oliveros’ philosophical and realized contributions to the AUMI movement, which until this book’s publication has received little attention.

Becoming Steve Bright, Robert L. Tsai

Kentucky Law Journal

No abstract provided.

Like Balance On Ice: Towards A New Approach To The Open And Obvious Doctrine Under Kentucky Law, Hayden T. Crosby

Kentucky Law Journal

No abstract provided.

Just A Place Or A Just Place?: Domestic Violence, Urban-Rural Differences, And Access To Justice, Cassie Chambers Armstrong

Kentucky Law Journal

No abstract provided.

Prosecutorial Discretion And Digital Democracy, Erin Sheley

Kentucky Law Journal

No abstract provided.

Steady Flow Over A Plate With Variable Fluid Properties In The Presence Of Magnetic Fields And Thermal Radiation, Jonas A. James, Makungu J. Ng'oga, Augustino I. Msigwa, Ahmada O. Ali

Tanzania Journal of Engineering and Technology (TJET)

The study examines a steady convective boundary layer flow model influenced by magnetic fields and variable fluid properties over the inclined plate. The governing model system of non-linear partial differential equations is transformed into a system of coupled non-linear ordinary differential equations through similarity transformations. These transformed equations are then solved numerically using the fourth-order Runge-Kutta method combined with the shooting techniques using MATLAB package because it is efficiency, stable and converge to the expected solutions compared with other methods. The numerical results detail the fluid velocity, temperature, concentration, and the local Sherwood number, Nusselt number, and skin friction coefficient …

Affordability And Usability Of Digital Learning Resources In Higher Education: A Case Of Online Mathematics Tutorials For Engineering Students At The University Of Dar Es Salaam, Fatuma S. Ikuja, Idrissa S. Amour, Abdi T. Abdalla

Tanzania Journal of Engineering and Technology (TJET)

Effective learning requires engagements with both learning contents and instructor’s personalized support. Large class sizes often limit opportunities for personalized instruction and timely feedback. Digital resources offer a viable solution to enhanced engagement and independent learning. This study investigated the affordability and usability of online digital learning resources for mathematics tutorials, specifically targeting engineering students at the University of Dar es Salaam. A quasi-experimental research design was adopted, focusing on digitization of undergraduate course: Matrices and Basic Calculus for Non-Majors (MT161). The course was delivered through the Moodle Learning Management System integrating STACK to support Mathematics questions. Data was collected …

Denoising Low Dose Ct Images Using Enhanced Autoencoder Deep Learning Model: A Phantom Study, Ali O. Masoud, Khamis O. Amour, Ahmed M. Jusabani, Adithya Rajnaryanan, Manoj Kumar, Yasir M. Haji, Mwingereza J. Kumwenda

Tanzania Journal of Engineering and Technology (TJET)

Reducing radiation dose in Computed Tomography (CT) inherently leads to increased image noise, which can compromise clinical interpretation. To address this limitation in Low Dose CT images (LDCT), numerous computational techniques particularly convolutional neural networks (CNN) have been explored for CT image enhancement. Various CNN architectures with different convolutional layer designs have been developed to improve image quality. This study evaluates the effectiveness of a developed CNN-based autoencoder for denoising LDCT images while preserving diagnostic integrity. An end-to-end CNN autoencoder with information bottleneck (IB) pipeline was designed and trained using CT phantom images with varying noise levels, aiming to suppress …

Dynamic-Based Assessment Of Shear Connectors In Composite Bridges With Data Taken From The Surface Of The Deck Slab, Emmanuel S. Leo

Tanzania Journal of Engineering and Technology (TJET)

Most bridge management systems generally rely on visual inspections for condition assessment; this means that damage in inaccessible parts of the structure, such as shear connectors in concrete composite bridges, can remain undetected until failure occurs. Localised non-destructive techniques are limited to small areas, time-consuming, and require prior knowledge of the damaged zone. These limitations can be overcome by using dynamic-based techniques. This study aims to investigate experimentally the efficiency of dynamic-based techniques in assessing the condition of shear connectors based on measurements taken from the surface of the deck slab. The study involved the construction of five composite beam …

Estimation Of Crop Water Requirements And Irrigation Demand For Maize And Rice In Morogoro, Tanzania Using The Cropwat 8.0 Model, Regina Pasiani, Johnson Mangesho, Paul Ts Limbu

Tanzania Journal of Engineering and Technology (TJET)

This study assessed the crop water requirements (CWR) and irrigation demands of maize and rice in Mvomero District, Morogoro Region in Tanzania, under varying seasonal rainfall and soil conditions. Using the CROPWAT 8.0 model, agrometeorological parameters such as temperature, rainfall, evapotranspiration, and effective rainfall were integrated with crop-specific characteristics and soil properties to simulate irrigation demands and quantify water needs across different crop phenological stages. The analysis employed decadal climatic data and crop coefficients (K_c) to simulate both the net and gross irrigation requirements. The findings revealed that maize, cultivated predominantly on red loamy soils, had a seasonal …

Impacts Of Climate Variability On Hydrological Response And Water Resources: Case Of Little Ruaha Catchment -Tanzania Using Ground And Chirps Data, Florence H. Mahay, Patrick C. Valimba, Madaka H. Tumbo, Fides J. Izdori, Leonard Maketa

Tanzania Journal of Engineering and Technology (TJET)

The Little Ruaha River catchment in Tanzania is increasingly affected by climate variability, with implications for agriculture, hydropower, and water supply. This study evaluates the effects of climate variability on rainfall and streamflow and assesses the usefulness of satellite-based rainfall data for hydrological modeling. Thirty-year records (1991–2020) of rain gauge and river flow data were analyzed using the Mann–Kendall test, and the HBV rainfall–runoff model was run with both gauge and CHIRPS satellite rainfall inputs. Annual rainfall exhibited no significant trends at most stations (p > 0.05), except for a notable decline at one eastern site. Seasonal rainfall and streamflow showed …

In-Depth Review Of Animal Anatomy In Veterinary Medicine, Fatima Ayad Hasan, Sarah Kamal Naser

Al-Bahir

This review explores the significance of animal anatomy across different fields, emphasizing both microscopic and macroscopic structures. The text covers teaching methods in veterinary medicine, with a focus on diagnostics and surgery. It also delves into various anatomical and moral issues, alongside contemporary teaching approaches. The importance of anatomy in both biological and clinical contexts continues to be central in advancing veterinary education, even with the presence of various digital tools and cutting-edge imaging technologies.

Health Implications Of Heavy Metal Contamination In Commercially Available Deodorant And Antiperspirant Products Sold In Benghazi, Libya, Maysson Yaghi, Khaled Elsherif

Al-Bahir

The extensive usage of deodorants and antiperspirants raises concerns about the potential health risks posed by heavy metal content. This study quantified the levels of five heavy metals: Aluminum, Zirconium, Lead, Cadmium, and Chromium in 22 commercial products widely used in Benghazi, Libya, and assessed the associated health risks. Samples, categorized into gel, stick, and roll-on formulations, were analyzed using iCAP TQ ICP-MS. Al and Zr showed the widest concentration ranges, reflecting their intentional use as active ingredients. Al levels ranged from trace amounts (0.032 mg/kg) up to a maximum of 99.10 mg/kg, while Zr was found exclusively in gel …

Takotsubo Cardiomyopathy In A 55-Year-Old Female With Atypical Chest Pain And A History Of Autoimmune Disease, Carrie Greene, Dana Mathew

Florida Journal of Emergency Medicine (FJEM)

A 55-year-old woman with rheumatoid arthritis and supraventricular tachycardia presented with acute chest pain radiating to the back/left shoulder, with nausea and lightheadedness. Initial ECG showed inferior–lateral ST-segment elevation with reciprocal depressions; within 90 minutes the STE resolved with new incomplete RBBB and diffuse low voltage. High-sensitivity troponin rose (delta ~270 ng/L). Point-of-care and formal echocardiography revealed LV wall-motion abnormalities. Emergent catheterization showed no obstructive CAD (<30% distal OM) with apical ballooning and EF 40–45%, consistent with Takotsubo cardiomyopathy; cardiac MRI confirmed myocardial edema. She was managed with anticoagulation initially, telemetry, and supportive care, and recovered uneventfully with normalization of function on follow-up.

ED Takeaways

• TTC can mimic STEMI with transient STE and conduction changes.

• Troponin rise + non-obstructive coronaries should prompt consideration of TTC.

• Consider TTC in post-menopausal women and those with autoimmune disease; use …

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Meningococcemia In Boy With Dense Deposit Disease Receiving C5 Complement Inhibitor Ravulizumab, Andrew Gonedes, Alexandra Martinez, Allan M. Greissman, Hanan Atia, Eric Boccio

Florida Journal of Emergency Medicine (FJEM)

No abstract provided.

Unexpected Companions: Appendicitis And Bilateral Testicular Torsion, Jc Alvarenga, Melissa Kirk, Michelle Osorio-Rodriguez

Florida Journal of Emergency Medicine (FJEM)

Abdominal pain is a frequent chief complaint in the emergency department (ED), responsible for 5% of all visits yearly. Despite emergency room work ups, 25% of these cases go undiagnosed. In the pediatric population, abdominal pain can be even harder to differentiate with causes ranging from low acuity constipation to emergent surgical emergencies like torsion or appendicitis. During these visits, the likelihood of two emergent surgical diagnoses occurring concurrently is a rare and often overlooked occurrence.

This case describes a 15-year-old male with a chief complaint of nausea and vomiting starting several hours prior to arrival. In the ED, history, …

Building Resilience One Connection At A Time: A Guide To Developing Retention Programming On College Campuses, Stephanie Sibley, Rachel Daltry

Journal of Access, Retention, and Inclusion in Higher Education

Despite college students having the potential to be more socially connected than ever before thanks to technology and social media, many students still struggle with isolation, loneliness, and a lack of belongingness and community. These feelings and experiences not only increase the risk for suicidal behavior and diminish resilience, but they can also negatively impact student retention. Outreach programming that targets social connectedness will be described. Specific guidelines developed from first-hand experiences with implementing such programming will be highlighted, and readers will be encouraged to consider how similar programming could be implemented by various offices or personnel at their own …