Digital Commons Network^™

Design And Synthesis Of Coke-Resistant Nickel-Based Catalysts For Efficient Methane Reforming And Hydrogen Production, Abdulmuizz Adamson

Dissertations

Ni-based catalysts are widely employed in methane reforming and cracking processes, however, their industrial application remains constrained by rapid deactivation caused by carbon deposition (coking). This thesis investigates the role of iron on the catalytic performance and coking resistance of the catalysts with focus on the mode of incorporation, oxidation state, reaction environment, and concentration of iron present as dopant.

The results show that doping the γ-Al₂O₃ support of Ni catalysts with well-dispersed iron ions in the support matrix significantly enhances catalyst stability during methane partial oxidation (POM) and combined dry reforming and partial oxidation (DR-POM). At 700°C, catalysts containing …

Fully Decentralized Hierarchical Federated Learning At The Edge With Post-Quantum Secure Communication, Tariq Qayyum

Dissertations

Federated learning (FL) enables collaborative model training without centralizing raw data, but deploying FL at scale in real edge environments remains challenging because iterative training and aggregation must operate over heterogeneous, resource-constrained, and often mobile devices with time-varying connectivity. Conventional hierarchical federated learning (HFL) partially mitigates communication cost by introducing fog/edge aggregation, yet many designs retain cloud-based global aggregation and cloud-centric coordination. This places wide-area network latency on the critical path of every training round, creates a single point of failure, and limits responsiveness as model sizes and federation scale grow. Moreover, moving coordination and aggregation closer to the edge …

Efficient Energy Management In Networked Microgrids Using Multi-Agent Deep Reinforcement Learning In The Presence Of Uncertainties, Ayodele Benjamin Chukwuyem

Dissertations

Microgrid technology is essential in facilitating the transition to smart energy grids in developed countries and mitigating energy poverty in developing countries, particularly in areas where grid extensions are not feasible. Recently, the concept of networked microgrids (NMGs) has garnered tremendous attention due to the plausibility of interactions among interconnected microgrids leading to power networks that are more resilient, reliable, and stable. However, because each microgrid has diverse distributed generation resources (renewables and controllable generators) and each microgrid operator (MO) has different objectives, coordinated energy management is required to satisfy local and system-wide goals under conditions with significant uncertainty. Existing …

Intelligent Deep Learning-Based Sign Language Translation System, Nada Rasem Shahin

Dissertations

The Deaf and Hard of Hearing (DHH) community uses sign language as a primary means of communication. However, the shortage of sign language interpreters and the existence of hundreds of sign languages limit accessibility and inclusion. Sign Language Machine Translation (SLMT) systems present a promising solution for bridging the communication gap between the DHH and the hearing individuals, supporting inclusive societies. In smart cities, such systems play an essential role in improving the quality of life on a community level. In particular, as the population’s well-being is critical, developing intelligent assistive technologies, such as SLMT systems, is necessary to provide …

Application Of The Tridiagonal Representation Approach And The J- Matrix Method Of Scattering In Theoretical Physics, Tunde Joseph Osunmusanmi

Dissertations

This dissertation is about the application of the Tridiagonal Representation Approach (TRA) in handling linear phenomenons, and for the first time, the J-matrix method of scattering in handling nonlinear phenomenons. The TRA is an algebraic method for solving linear ordinary differential equations of the second order. The advantage of the method in being algebraic is reinforced by the analytic power of orthogonal polynomials and special functions. On the computational side, it is favored as being reliant on powerful numerical techniques that deal with tridiagonal matrices such as Gauss quadrature and continued fraction. In the method, the solution of the differential …

A Low-Noise And High-Gain Integrated Photoplethysmography Sensor For Continuous Vital Signs Monitoring, Neethu Mohan

Dissertations

Photoplethysmography (PPG) sensing is an important technology used for measuring health parameters like, heart rate, respiratory rate, blood oxygen saturation, and blood pressure (BP). The PPG sensing is used for individuals who have to periodically monitor their health due to chronic health conditions. The basic requirements of a wearable PPG sensor include non-invasiveness, prolonged battery life, and being userfriendly. These type of sensors have great demand in the healthcare applications and there is a significant rise in the demand of these sensors. The basic objective of these PPG sensors is to make the continuous vital health monitoring easier without the …

Examining The Impact Of Restorative Practices On Student Behavior, Discipline, And Relationships In A K–5 Elementary School, Kathleen Tomaszewski

Dissertations

This study examined the implementation of restorative practices in a K–5 elementary school and their influence on student behavior, disciplinary actions, and teacher–student relationships. Restorative practices in schools focus on building a positive school climate and addressing student behavior through community and relationship-building rather than punitive measures. The rationale for the study was grounded in concerns regarding the use of exclusionary discipline practices and the need for proactive, student-centered approaches to improving school climate. Two main research questions guided the inquiry: To what extent do restorative practices impact student referrals and disciplinary actions in a K-5 elementary school? How do …

Feedback In Digital Game-Based Learning: A Taxonomy And The Design And Empirical Evaluation Of A Feedback System In A Mathematics Serious Game, André Almo

Dissertations

Digital Game-Based Learning (DGBL) is an active, student-centred pedagogical approach in which feedback plays a central role by informing learners’ actions, guiding decision-making and shaping motivation and engagement. Despite its importance, feedback in serious games is often described inconsistently and insufficiently in research, limiting comparability across studies and the accumulation of design knowledge, particularly for children. This thesis addresses these gaps through two complementary contributions: the development of a taxonomy for feedback design in digital serious games and the empirical evaluation of a taxonomy-informed feedback system in a mathematics game for primary school students. First, this work introduces the Taxonomy …

Utilization Of National Guard Cyber Forces In Title 32 Status For National Cyber Missions, David A. Schroeder

Dissertations

There has been a debate for more than a decade in the United States about the precise role National Guard and Reserve military forces, and the National Guard in particular, can and should play in cyberspace operations. There are legal, policy, doctrinal, organizational, cultural, and bureaucratic issues that must be overcome or understood to employ National Guard forces for national cyber operations. Leaders in Congress, U.S. Cyber Command, and the National Guard have clearly articulated the need to leverage the cyber expertise in the National Guard in defense of the nation. Papers, articles, and hearings have repeatedly examined the existing …

Quantum Safe Encryption (Qse) Within The Internet Of Medical Things (Iomt) Environment Using Zero Trust Architecture (Zta), Michael Grant Williams

Dissertations

This research will use a Design Science Research (DSR) methodology and show that the results would be feasible, since there will not be any actual validating or testing occurring within or on this research project because this model is a theoretical model. In addition, this proposed theoretical model is based on extensive use of NIST standards and frameworks. This theoretical model will focused on the use of Quantum-Safe Encryption (QSE) within the Vivalink Electrocardiogram (ECG) Patch Monitor Internet of Medical Things (IoMT) device in a Zero Trust Architecture (ZTA). The advancement of quantum computing (QC) is expected to …

A Capability Maturity Model For Artificial Intelligence Integration In Supply Chain Management, Lordt Becklines

Dissertations

Artificial Intelligence (AI) is transforming Supply Chain Management (SCM), yet many organizations struggle to assess their readiness for AI adoption and to understand how AI capabilities develop across maturity stages. This dissertation addresses this gap by developing a Capability Maturity Model (CMM) for AI integration in SCM, grounded in Organizational Information Processing Theory (OIPT), the Resource-Based View, and related capability frameworks. The model provides a structured approach for evaluating an organization's information-processing requirements, resource configurations, and alignment needed for effective AI-enabled supply chain operations.

Using a design science research approach, the AI-SCM CMM and its associated assessment instrument were derived …

How Principals Who Use Artificial Intelligence For Innovation Create Cognitive Equity While Principals Who Use Ai For Efficiency Create Cognitive Debt, Jethro Jones

Dissertations

This dissertation in practice examined whether a targeted professional learning   intervention could shift school leaders’ use of generative artificial intelligence (AI) from efficiency-oriented tasks toward innovation-oriented strategic problem solving. AI is typically adopted to accelerate existing routines, which can deepen “cognitive debt” by reinforcing ineffective practices rather than improving systems. This study advanced a “cognitive equity” frame, positioning AI as a tool that can expand principals’ cognitive capacity to address complex problems and lead adaptive change. Using a quasi-experimental, single-group design, the study evaluated a free, full-day AI for Innovation workshop, which emphasized foundational understanding of how AI tools work …

Optical Fiber Sensors Using Vernier Effect In Cascaded Fiber Interferometers, Zhouchen Wang

Dissertations

The optical Vernier effect has emerged as a powerful tool to enhance the sensitivity of optical fiber interferometer-based sensors, opening new opportunities for developing highly sensitive fiber sensing systems. Optical fiber interferometric sensors based on the Vernier effect are widely used for various applications due to their ultra-compact size, high sensitivity, immunity to electromagnetic interference, electrical isolation, resistance to harsh environments, flexibility, multiplexing capability, and remote operation. The aim of this doctoral thesis was to gain a deeper fundamental understanding of the Vernier effect in optical fiber structures and to develop and investigate a series of novel Vernier effect optical …

The Effects Of A Viniyoga-Based Practice On Mental Health Clinicians' Perceived Stress, Burnout, And Quality Of Life, Julie Pate

Dissertations

Psychotherapists often experience stress when treating distressed or emotionally troubled patients due to the emotionally taxing nature of their work, which can lead to burnout and other negative consequences (Bell et al., 2023; Maslach & Leiter, 2016; Simionato & Simpson, 2018) Therapists find it challenging to maintain regular self-care routines (Driscoll, 2023; Baker & Gabriel, 2021; Posluns & Gall, 2020). With the constant demand for counselors (Bureau of Labor Statistics, U.S. Department of Labor, 2024), there is a critical need for effective stress management strategies to mitigate burnout risks (Substance Abuse and Mental Health Services Administration [SAMHSA], 2022; Sibitz, Pils, …

The Voices Of Educators And Elders: Examining A Supplemental Educational Program Through A Culturally Responsive Lens In Gullah Geechee And African American Communities, Kelly D. Shelton

Dissertations

African American students in South Carolina experience historical educational suppression (Anderson, 1988; Bowers et al., 2018; Fabel, 2019). This qualitative case study investigated how the use of African Diaspora and Gullah Geechee culture in supplemental education programs supported the academic success of youth. Using a culturally and historically responsive literacy and critical race theoretical framing (Gay, 2013; Hammond, 2015; Ladson-Billings, 2014; Ladson-Billings & Tate, 1997; Mills, 1997; Muhammad, 2020), this study captured the voices and insights of community elders and program directors of The Village Group, that makes use of Gullah Geechee cultural, academic, and vocational practices to engage and …

Selling The Spell: The Commodification Of Feminist Witchcraft, Noël Subrina Sucese

Dissertations

"Selling the Spell" argues that Feminist Witches, or Crafters, navigated a fraught relationship with consumer culture, at once resisting commodification, embracing it, and reshaping it in ways that carried spiritual, political, and economic consequences. Drawing on oral histories, archival and digital sources, this dissertation traces the evolution of American Feminist Witchcraft and related Pagan traditions from the 1960s through the early 2000s. It situates the Craft at the intersection of feminism, counterculture, and capitalism, showing how spiritual practices that emphasized female embodiment and communal ritual became entangled with publishing, festivals, consumer goods, and the Internet. The dissertation contributes to four …

Understanding Early Childhood Community Collaborations (Ecccs) In Relation To Systems Change, Rebecca Waterstone Halperin

Dissertations

The early childhood system in the United States is piecemeal and fragmented (Adams et al., 2017; Gomez & Rendon, 2019; Kagan & Kauerz, 2012; State Capacity Building Center, 2022). The result is that families have unequal access to care, education, and other early childhood services for their young children. There have been various approaches to building, impacting, and changing the early childhood system to move toward equity, and many of these approaches call for collaborative efforts. The state of Illinois is engaged in comprehensive early childhood systems work, and one of the vehicles driving this change has been the work …

Revisiting Collective Efficacy: Insights From Cognitive Interviews And Experimental Surveys, Tori Kay Olson

Dissertations

This three-part study revisits the collective efficacy scale developed by Sampson and colleagues in the 1990s to see if the scale needs updating. Defined as community cohesion and social control, collective efficacy is often used in community research to explain crime rates. The first phase uses cognitive interviews to understand how survey respondents interpret the original collective efficacy survey. The interview data then helps create new versions of the ten questions in the second phase. In the third phase, ChatGPT generates a revised version of the collective efficacy scale. The study employs a split-ballot experimental survey to test whether the …

In Search Of Resilience: A Case Study Of Leadership In Challenging Times In An International School Setting, Bradylee W. Mcgeough

Dissertations

This study investigated the leadership of a long-serving head of an international school during six periods of significant crisis affecting the school. The study was conducted at a private school in Islamabad, Pakistan, often referred to locally as The American School.

The study paid particular attention to the development of resilience in the leader and in the follower group during and after periods of crisis. Initially designed as a heuristic inquiry, in practice the study emerged more as a collection of oral histories, although heuristic inquiry methods were employed throughout the study. Polkinghorne’s conception of narrative analysis also …

Investigating Host Factors In Coronavirus Assembly And Egress, Surovi Binte Sharmin Mohona

Dissertations

Coronavirus (CoV) structural proteins congregate at the ER-Golgi intermediate compartments (ERGIC) prior to virus budding into the organelle lumen. Subsequent trafficking and fusion of virus-containing, ERGIC-derived vesicles then release nascent viruses from infected cells. Our findings in this dissertation illuminate mechanisms by which CoV structural proteins coalesce at the virus assembly and budding sites. The cytoplasmic tails of all CoV spike (S) glycoproteins contain variants of a consensus KxKxx coatomer-binding motif. Host coatomer complexes facilitate retrograde trafficking of client cargo proteins via recognition of such motifs. Utilizing reverse genetics methodologies, we introduced variations in the S coatomer motif in a …

Thermal Analysis Of The Fiber Fuse Effect, John Seekins

Dissertations

The fiber fuse effect is a self-sustaining damage propagation mechanism that can occur in the core of optical fibers. Under sufficient levels of applied power, laser light is absorbed as heat in the fiber. This phenomenon is characterized by a brightly glowing spot in the fiber that propagates towards the source of laser light at about 1 𝑚/𝑠. A numerical simulation of the fiber fuse effect is developed that solves the transient heat equation with source terms in cylindrical coordinates utilizing an explicit finite difference discretization. For the first time in a simulation of this type, a radiation transport equation …

Rocket Injector Flowfield Characterization Through Local, Instantaneous Gas Composition Tracing Using Laser Induced Breakdown Spectroscopy, Michaela Renee Hemming

Dissertations

Laser induced breakdown spectroscopy (LIBS) was developed for applications in the characterization of rocket engine injectors to evaluate the instantaneous, local gas concentration, or local mixture ratio of the injector flowfield. In this work, LIBS was tested in steady flows of premixed methane and air to create the correlation of the LIBS spectral species ratios H/O ratio, followed by a steady non-premixed flow to extract the localized mixing and shape of the flow field, then a transient study was performed to measure the development of the flow of the reactants in a pentad impingement injector previously used in RDE tests. …

An Explanatory Mixed-Methods Study Identifying And Describing The Perceived Impact Of Five Disruptive Career Skills On Women’S Career Advancement To An Executive Leadership, Roque Ramirez

Dissertations

Purpose: The purpose of this explanatory mixed-methods study was to identify and describe the perceived impact of Johnson and Mohr’s (2019) five disruptive career skills on the career advancement of female chief petty officers with a military background as they progressed into a leadership position.Methodology: This explanatory mixed-methods study examined the experienced of eight female chief petty officers regarding the use of personal disruption strategies. Participants were selected through purposive sampling based on predetermined eligibility criteria and recommendations. Data were collected and analyzed by calculating means scores for quantitative responses and identifying qualitative themes related to the five personal disruption …

The Geometry Of Seminormed Spaces With Applications To The Fixed Point Theory Of Operators Defined On Geometric FréChet Spaces, Quinten Ryan Mckinney

Dissertations

A geometric theory of seminorms is introduced and exposited. The concept of a G-Space, which is a Frechet which holds the sequence of seminorms that generate its topology as intrinsic to its definition, is introduced. Abstract results which involve concluding, from the existence of common pseudo-fixed points of a family of operators on a G-Space, the existence of a common fixed point for that family, are presented. These results are exploited to prove the existence of fixed points of some operators defined on totally closed, convex subsets of certain G-Spaces. Three specific fixed point scenarios are addressed. The first is …

Grit And Inclusive Practice: A Phenomenological Study Of General Education Teachers In A Title I Elementary School, Andrea Martinez

Dissertations

Purpose: The purpose of this qualitative phenomenological study was to describe elementary general education teachers' perceptions of how the core principles of grit, as defined by Duckworth et al. (2007); passion, perseverance, resilience, goal commitment, and growth mindset, influence their ability to implement inclusive practices for students with disabilities in general education classrooms.

Methodology: A qualitative phenomenological design was used to explore the lived experiences of elementary general education teachers. Purposeful sampling was used to identify participants who met the study criteria. Eight elementary general education teachers employed at a Title I public elementary school in Kings County, California, participated …

The Art Of Crisis Leadership By Exemplary Naval Frontline Leaders, Broadus Brooks

Dissertations

Purpose: This qualitative, multiple-case study held significant importance because it aimed to identify and describe the strategies used by exemplary naval frontline leaders to lead in crisis, particularly during the COVID-19 pandemic. The study focused on the five critical tasks of strategic crisis leadership (sensemaking, decision making/coordination, meaning making, accounting, and learning), providing a unique insight into the experiences of these leaders during a crisis.Methodology: This qualitative, multiple-case study employed interviews to collect data from exemplary naval frontline leaders to identify and describe their leadership strategies during the unprecedented COVID-19 global health crisis.

Findings: Crisis leadership among U.S. naval frontline …

The Adolescent Development Of Small Business Owners’ Entrepreneurial Mindset, Fern Arredondo

Dissertations

Purpose: The purpose of this phenomenological study was to describe how small business owners in Southern California interpret experiences before age 20 that influenced the development of the eight domains of the Network for Teaching Entrepreneurship (NFTE) Entrepreneurial Mindset Index (EMI). This study used a qualitative phenomenological approach to explore how adult small business owners reflect upon and interpret experiences before age 20 that influenced the development of their entrepreneurial mindset. By examining the influence of pre-adulthood on these owners, the study aimed to deepen the understanding of how early experiences shape entrepreneurial mindsets and contribute to long-term entrepreneurial success. …

Rewriting The Future: Examining The Influence Of Mentoring On Ged Graduates' Pursuit And Performance In Postsecondary Education, Shari Antoinette Crain

Dissertations

This phenomenological study explored the lived experiences of GED graduates who were mentored while earning their GED and examined how those mentoring experiences contributed to their academic achievement in community college. Although increasing numbers of adult learners pursue postsecondary education through the GED pathway, many encounter barriers related to academic confidence, institutional navigation, and access to support systems. Limited research has examined how mentoring supports GED graduates during their transition into higher education.

Guided by the College Student Mentoring Scale developed by Nora and Crisp (2009), this study examined mentoring experiences across four domains: psychological and emotional support, degree and …

Meeting Battery Electric Vehicle Demand With A Focus On Throughput Capacity Across The Transport Nodes In The Upstream Cobalt Supply Chain, Nicholas J. Visconti

Dissertations

This study assesses whether cobalt transport capacity in sub-Saharan Africa is sufficient to support projected battery electric vehicle (BEV) demand under the Paris Accord. Using open-source data from ArcGIS, the Highway Capacity Manual, and the World Bank, the analysis applies a simplified linear programming approach to estimate the maximum throughput of the primary transport corridor connecting the Democratic Republic of the Congo to the Port of Durban. The model identifies significant constraints along the Rutenga-to-Beitbridge segment, reducing network capacity to an estimated 42,494 tons of ore per day. When converted to refined cobalt, this capacity falls well short of the …

A Qualitative Multiple Case Study Exploring Shifts In Thinking Of Principals Through Initiatives To Foster Relational Leadership Conducive To Retaining Teachers In High-Minority, High-Poverty Public Schools, Rita Seay

Dissertations

Problem

The public education system is broken, and teacher shortages have reached a crisis, especially in some specialty fields in United States (Carrillo & Salhotra, 2022; Podolsky et al., 2016). Lately, the teacher workforce has been described as a “leaky bucket” (Podolsky et al., 2016, p. 1). Indeed, the problems are complex in poor socioeconomic communities with racial and ethnic groups of students because teachers struggle to make a difference and, in most cases, fail due to insurmountable situations that are beyond their scope of influence (Rondfeldt et al., 2013). Evidence published that students suffer immensely from a broken, segregated …