Digital Commons Network^™

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 …

Improving The Electrochemical Properties Of Mno2 By Doping With Fe For Water Splitting And Supercapacitor Application, Joseph Okwe

Electronic Theses & Dissertations

An Abstract of the Thesis by

Joseph Okwe

These days when the issue of energy is talked about, it is usually more than just the usefulness of different types of energy. This topic now encompasses ways of generating and storing energy in the most efficient and sustainable way. For this reason, various research has shown that materials that are fabricated for the purpose of energy storage and conversion also find applications in other areas such as water splitting and supercapacitors. And so certain materials, when synthesized, can serve more than one purpose in either generating or storing energy. This project …

2025 Fall Commencement, Harding University

Commencement Programs

Program for the Harding University Commencement on December 13. 
Commencement Speaker: Dr. Susan Kehl

From Public To Private: Understanding Parental Perceptions On Middle School Transitions, Joseph P. Peeden

Ed.D. Dissertations

The purpose of this qualitative study was to explore parents/guardians’ perceptions of their children’s transition from elementary to middle school, focusing on transitions to private middle schools and differences based on prior schooling (private versus public elementary) and gender. In this study, I addressed the lack of understanding regarding how private education transitions impacted students academically, socially, and culturally, including challenges related to social-emotional learning and cultural adjustment. I collected data from 75 parents/guardians using questionnaires and conducted 20 follow-up interviews in the Southeast United States to examine their experiences. I found that students transitioning from public schools to private …

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 …

A Comprehensive Study Of Clique Graphs And Clique Regular Graphs, Connor Phillips

Senior Honors Projects, 2020-current

If Γ is a graph for which every edge is in exactly one clique of order ω, then one can form a new graph with vertex set equal to these cliques.  This is a generalization of the line graph of Γ.  We discover many general results and classifications related to these clique graphs that will be useful to researchers studying graphs with this property. In particular, we find bounds on the spectrum of Γ (with exact results when Γ is k-regular) and some complete classifications when Γ is strongly regular. We apply our results to derive novel information about the …

Contemporary Martian Geomorphic Processes And The Suitability Characterization Of Terrestrial Analogues, Daniel Paul Mason

Earth and Planetary Sciences ETDs

Both historical and contemporary evidence for geomorphic activity on the surface of Mars is apparent. This evidence is showcased by features including a) well-preserved deltaic remnants in an otherwise cold and arid environment, present along the western flank of Jezero Crater, and b) the seasonal appearance of candidate recurring slope lineae throughout Martian equatorial, lower, and mid-latitudes as seen within both the Eos Chasma region and on the walls of Raga, Lohse, Rauna, and Tivat Craters. In this dissertation, I elucidate the role that geomorphic processes, whether aqueous or dry, have played in shaping both the ancient and contemporary Martian …

When Two Worlds Collide: A Narrative Inquiry Into The Teacher Identity Development Of Graduate Students Of Additional Languages, Hannah L. Garver

Teacher Education, Educational Leadership & Policy ETDs

This study explores a population that has been understudied in teacher identity research: native English-speaking graduate teaching assistants (GTAs) of additional languages who assumed this role with no prior teaching experience. Influenced by my own experience as a GTA, the purpose of this study is to gain insight into how this population’s experiences shape their identities as teachers and later careers. This qualitative study uses narrative inquiry as a method by which to examine their experiences through the stories told by participants: six former GTAs of French and German.

Using data in the form of semi-structured interviews and some participants’ …

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 …

Arcsine Ratio Sine Generalized Distributions With Applications To Biomedical And Engineering Data, Kizito E. Anyiam, Mohamed A. F. Elbarkawy, Ehab M. Almetwally, Okechukwu J. Obulezi, Mohammed Elgarhy

Mesopotamian Journal of CyberSecurity

gonometric distributions offer a powerful approach to solving complex problems in probability and statistical modeling. In this study, we introduce a novel class of distributions: the Arcsine Ratio Sine Generalized (ARS-G) family. We provide a complete set of explicit formulas for the family’s statistical properties. Our key illustration is the ARS-Weibull (ARS-W) distribution, which uses the Weibull model as its foundation. This particular model demonstrates remarkable flexibility, with its hazard function capable of assuming diverse shapes, including bump, bathtub, reversed bathtub, J-shaped, and L-shaped profiles. We thoroughly examine the ARS W distribution’s statistical properties and employ various established estimation methods …

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 …

Modeling Mineral Redistribution In Biological Tissue Using Apple As An In Vitro Analogue, Daler Djuraev, Ali Algemsh, Halima Alazeb, Zeenia Ahmed

Publications and Research

This project aims to model mineral (ion) redistribution that occurs in human soft tissue after injury or mechanical/thermal stress. Because direct, repeatable in vivo measurements are difficult, we use apples as an in vitro analogue: their mineral content is relatively uniform and the tissue can be cut, dried, and repeatedly imaged under controlled conditions. Using X-ray imaging, we tracked how minerals in apple tissue move toward damaged regions immediately after cutting, and how subsequent drying at room temperature drives a redistribution toward the central core. We also observed that biological degradation (decay) alters mineral density over time, indicating that even …

Assessment Of Fish Community Dynamics, Movement, And Morphology In Relation To Stream Barriers In The Upper Illinois Bayou Watershed, Risa Mccollough

ATU Theses and Dissertations 2021 - Present

Intermittent streams are increasingly recognized as vital components of river networks by supporting dynamic fish communities shaped by variable hydrology and habitat connectivity. They are becoming increasingly vulnerable to fragmentation by anthropogenic activities, namely road crossings, dams, and climate shifts that intensify seasonal drying. In response, I conducted two studies in the Illinois Bayou watershed in Arkansas to assess the effects of fragmentation on fish community dynamics and morphology in intermittent streams.

In the first study, I examined temporal fish community dynamics across two barriers: a natural waterfall in Dare Creek and a low-water crossing in Dry Creek. Simultaneously, I …

Graph Based Planning With Guarantees, Trazon Tyrik Jimerson

Mechanical Engineering ETDs

This thesis presents two graph-based methods with formal guarantees for motion planning and routing. First, the invariant-set motion planner (ISMP), which uses constraint admissible positive invariant (CAPI) sets of closed-loop dynamics, is adapted for spacecraft attitude planning to avoid moving keep-out zones. Contributions include time bounds for maneuvers via exponential stability, a single-stage reachability graph from one-step backward reachable CAPI sets, and its multi-stage expansion to certify node safety over time. Simulations verify safe attitude control with moving obstacles. Second, we formulate a convex optimization problem over a network for evacuation planning with operational constraints such as helicopter capacity and …

Real-Time Frequency Tuning Of Kinetic Energy Harvesters Via System Mass Adjustment, Rahul Adhikari

Mechanical Engineering ETDs

This research presents a method for real-time frequency tuning of piezoelectric kinetic energy harvesters through system-mass adjustment. Custom 3D-printed proof masses with cavity arrays were used to redistribute solid or liquid mass, enabling controlled modification of resonant frequency. Experimental studies using microparticles and liquids—including water, silicone oil, and sodium polytungstate—demonstrated an achievable tuning range of 115.27 Hz with sub-hertz resolution (< 0.1 Hz), confirming precise and repeatable frequency control. Finite-element modeling guided design optimization, while a microfluidic channel system enabled automated liquid filling for real-time operation. A MATLAB-based EH_Tuning application was developed to visualize and predict frequency responses. The combined …

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% …

Lycopene, Race And Periodontitis: Disparities In Older Adults, Katherine Kwong, You Lu, Zhuo Huan Li, Susu Luo, Zhaoyu Huang, Zhong Chen, Na Zhao, Tung Sung Tseng

School of Public Health Faculty Publications

Background Periodontitis is a severe gum disease that can be an indicator of other health conditions such as cardiovascular disease and diabetes. Lycopene has been suggested as an adjunct therapy for periodontitis. This study aims to investigate the association between insufficient lycopene intake and the risk of Periodontitis among non-Hispanic White (NHW) and non-Hispanic Black (NHB) older adults. Methods The study included 1,227 adults aged 65–79 years from the National Health and Nutritional Examination Survey (2009–2014). Total lycopene intake from daily diet was studied with age, race, marital status, smoking status, BMI, diabetes, sex, and education as independent variables in …

Do Stakeholders Benefit From Green Bonds Denominated In Euro? Evidence From Global Greenium, Piotr Jaworski

Journal of Banking and Financial Economics

The aim of this paper is to estimate the greenium in the financial debt market, calculated as the difference between the yield of green bonds and conventional bonds with the same type of with respect to euro-denominated bonds, type of the debt security, type of issuers, and maturity. The hypothesis is The greenium for the euro-denominated bonds does exist. For the analysis, yield curves for green bonds and conventional bonds were built. It employed the yield curve methodology proposed by Nelson Siegel Svensson. Statistical tests on greenium were also prepared. Daily data were collected from the Refinitiv Eikon database, covering …

Dynamic Admittance Parameterization For Non-Prehensile Multi-Robot Transport With Optimal Coordinated Planning, Calvin J. Stahoviak

Computer Science ETDs

The Dynamic Admittance Parameterization of Non-Prehensile Multi-Robot Trans- port with Optimal Coordinated Planning (DYNAMO) architecture offers a practical framework for cooperative payload transportation using two robots equipped with nonholonomic mobile bases and four-degree-of-freedom manipulators. Coordinated mobile manipulation is a difficult problem in robotics, and the non-prehensile case is even more challenging than its prehensile counterpart because the robot bases and the payload are dynamically coupled. DYNAMO adapts arm motion in response to interaction forces and generates coordinated base trajectories that account for this coupling. Robust payload transport is achieved through the combination of opti- mal planning and adaptive compliant control, …

Recreating Fiber Recruitment With Fiber Recruitment Using Additive Manufacturing, Natalia D. Mciver

Biomedical Engineering ETDs

Injured ligaments are often repaired with tendon grafts which may over or under constrain the joint; there is a need for an artificial graft option with the mechanical properties of a native ligament. Crimped fibers within ligaments allow for recruitment which means the viscoelastic properties of stress relaxation and creep are not inversely related. A feasibility study using ACLs and large-scale crimp models to study viscoelasticity, led to an in-depth analysis of the scapholunate interosseous ligament. Using the Modified Kelvin spring-dashpot model, for describing viscoelasticity with a variable stiffness property (time dependent fiber recruitment), we defined the relationship between creep …

Needs Analysis: Ar As An Innovative Learning Media Solution For Elementary School Students, Rosfaniarti Rosfaniarti, Makmum Raharjo, Meilinda Meilinda

Jurnal Pendidikan: Teori, Penelitian, dan Pengembangan

This study aims to identify the need for the development of Augmented Reality (AR)-based learning media as an innovative solution in elementary school learning. The needs analysis method was conducted using a mixed methods approach through questionnaires and interviews with 103 students and 5 teachers. The data were analyzed descriptively and quantitatively to obtain a comprehensive picture of instructional needs. The results showed that student needs were in the high category, with a percentage of 80.64%-85.30%. The socio-cultural aspect was the highest need (85.30%), followed by the pedagogical and technical aspects, while the cognitive aspect had the lowest value (80.64%). …

In-Situ Determination Of Tension Zone Of Sediments By Using Dynamic Light Cone Penetration Test: Tropical Sediments In Tanzania, Francis K. Mutabazi, Gabriel D. Mulibo, Dalmas L. Nyaoro, Keneth Lupogo

Tanzania Journal of Engineering and Technology (TJET)

Dynamic probing of the light hammer (DPL) has been analysed by plotting the penetration index (blows per 10 cm penetration depth). The information obtained provides vital insight into ground profile variation. However, the results presentation and analysis have not been sufficiently investigated in ascertaining more information on the ground properties; therefore, focus on additional analysis techniques are needed to reveal further ground information. This paper aims at exposing the potential of using total penetration blows plots for examining the ground characteristics, narrating procedure for such graphical analysis. The analysis of the results, using total blows on linear and log scales, …

Design And Testing Of Adaptable Piston Damping Mechanism For Rapid Compression Machine, Myeji C. Materego

Tanzania Journal of Engineering and Technology (TJET)

A Rapid Compression Machine (RCM) is, essentially, a piston housed inside a cylinder. Its main objective is to compress a combustible mixture as rapid as possible to a higher temperature and pressure at which its auto ignition characteristics can be studied. Such machines are useful in the study of engine fuels autoignition behaviour because they provide a good representation of a single stroke compression ignited engine. There are various designs and operation techniques of RCM, but they all have to possess a key characteristic of compressing the fuel mixture rapidly while producing minimum heat and mass loss, turbulence and pressure …

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 …

Space Vectors Discretization-Based Direct Torque Control Scheme For High Performance Induction Motor Drives, Francisco Balenga, Francis Mwasilu

Tanzania Journal of Engineering and Technology (TJET)

In this paper, a direct torque controller (DTC) based on discretization of space vectors (DSV-DTC) for induction motor drives is proposed. By using this technique, the number of voltage vectors is increased, consequently it reduces the torque ripple compared to the conventional DTC control scheme. Specifically, the switching table of the proposed DSV-DTC scheme is comprised of thirty-six nonzero voltage vectors compared to the six voltage vectors in the conventional DTC scheme. Furthermore, it makes use of a five – level torque hysteresis comparator instead of three-level of the conventional DTC. The performance of the proposed control scheme is validated …

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 …

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 …

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 …