Digital Commons Network^™

N-Radii Approach For Multi-Scale Characterization Of Graphite Shape In Cast Iron, Simon N. Lekakh, Laura Bartlett

Materials Science and Engineering Faculty Research & Creative Works

Knowledge of multi-scale particle macro-shape and micro-surface topology is critical in many technical disciplines. Specifically, quality assessment of the shape of the graphite phase in cast irons is essential for day-to-day metal casting operations. Common methods for evaluating particle macro-shape have several drawbacks, often resulting in underestimation of sharp corners and surface texture. In this article, a method based on plotting n-radii from the center of mass to the perimeter and computing multi-scale topological characteristics is described and tested. Parametric tests, involving variations in the number of n-radii and image resolution, were performed to optimize the test parameters. The method …

Modeling Of Transformation Temperatures In Cast Martensitic Stainless Steels-Ca6nm: Effects Of Composition, Heating Rate, And Grain Size, Ugochukwu Agbedo, Mario Buchely, Laura Bartlett, Caelan Kennedy

Materials Science and Engineering Faculty Research & Creative Works

Accurate prediction of the critical transformation temperatures Ac1 and Ac3 is one of the essential factors in the heat treatment of CA6NM cast martensitic stainless steel. In this study, the influence of alloy composition, heating rate, and prior austenite grain size on the critical temperatures was quantified using dilatometric measurements and statistical modeling. Six heat treatment conditions produced prior austenite grain sizes ranging from ~75 to 247 µm. Experimental results showed that grain size variations produced only minor changes in Ac1 and Ac3, indicating a weak dependence of transformation temperatures on prior austenite grain size within the investigated range. In …

Multiphysics Simulation And Experimental Validation Of Phase Transformation And Hardness In Jominy End-Quenched Low-Alloy Steels, J. S. Alabi, E. Heidari, M. F. Buchely, K. Chandrashekhara, S. N. Lekakh, R. J. O'Malley, V. A. Athavale, A. Kumar

Materials Science and Engineering Faculty Research & Creative Works

High-volume industrial continuous hot-rolled steel heat treatment processes involve sophisticated multi-phase modeling. The performance of a given process can be optimized by coupling phase transformation kinetics with the cooling conditions of the process. This study develops a multiphysics model to simulate an intensive quenching process for steel, which is inherently transient and highly dependent on numerous parameters. The simulated object was a Jominy end-quenched specimen geometry using two commercial steels, AISI 4130 and AISI 4140, with the goal of transferring a verified methodology to the heat treatment process for industrial heavy-section products (bars, slabs). The simulation employs thermal, mechanical, and …

Global Characterization Of Stratospheric Sulfate Aerosols By The Atmospheric Chemistry Experiment (Ace), Peter Bernath, Manish Bhusal, Michael Lecours, Chris Boone

Chemistry & Biochemistry Faculty Publications

Stratospheric sulfate aerosol (SSA) is an important part of the Earth's climate system. SSA climate impact is determined in part by particle composition, which has been measured from orbit. The weight percent of sulfuric acid in SSA has been determined from atmospheric infrared transmittance spectra recorded with the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) in limb geometry using the Sun as a light source (solar occultation). The global average SSA composition varies from about 50 to 80 percent with lowest values during the Antarctic winter. Atmospheric extinction at a wavelength of 1 μm was included in the analysis to …

An Updated Infrared Solar Spectrum From Ace-Fts And A Ch Rovibrational Line List, Manish Bhusal, Peter F. Bernath, Léo Lavy, Chris D. Boone, Frank Hase

Chemistry & Biochemistry Faculty Publications

An updated Atmospheric Chemistry Experiment Fourier Transform Spectrometer infrared solar spectrum has been produced from low-Earth orbit covering 1829-4440 cm^-¹ (2.252-5.467 mu m). Spectroscopic constants for the v = 4 and v = 5 vibrational levels of the X²Π state of CH radical have been updated by incorporating additional vibration-rotation lines from the new solar spectrum and from an archival laboratory spectrum. New ab initio calculations of the permanent dipole moment function for the X²Π state were performed with the MOLPRO quantum chemistry package using the internally contracted multireference configuration interaction method. This dipole moment function, along with …

Radial And Carotid Arterial Pulse Signals For Assessing Cardiovascular Function At Rest And During Post-Exercise Recovery In A Heart Transplant Patient: A Case Study, Md Mahfuzur Rahman, Mamun Hasan, Jennifer F. May, John M. Herre, Leryn Reynolds, Zhili Hao

Mechanical & Aerospace Engineering Faculty Publications

Aim: This study investigates the feasibility of using radial and carotid arterial pulse signals to assess cardiovascular (CV) function at rest and during post-exercise recovery in a heart transplant (HTx) patient. Method: Two micro-fabricated tactile sensors were used to simultaneously acquire arterial pulse signals at the radial artery (RA) and carotid artery (CA). Measurements were taken at rest and at multiple time points post-exercise on three subjects: an HTx patient, a percutaneous coronary intervention (PCI; coronary stent) patient and a healthy control. An SDOF-TF-based time-frequency analysis algorithm was applied to extract a comprehensive set of CV parameters, including heart rate …

Supercharging Simulation-Based Inference For Bayesian Optimal Experimental Design, Samuel Klein, Willie Neiswanger, Daniel Ratner, Michael Kagan, Sean Gasiorowski

Physics Faculty Publications

Bayesian optimal experimental design (BOED) seeks to maximize the expected information gain (EIG) of experiments. This requires a likelihood estimate, which in many settings is intractable. Simulation-based inference (SBI) provides powerful tools for this regime. However, existing work explicitly connecting SBI and BOED is restricted to a single contrastive EIG bound. We show that the EIG admits multiple formulations which can directly leverage modern SBI density estimators, encompassing neural posterior, likelihood, and ratio estimation. Building on this perspective, we define a novel EIG estimator using neural likelihood estimation. Further, we identify optimization as a key bottleneck of gradient based EIG …

Development Of Thermal Joints For Conduction-Cooling Applications, J. Lewis, G. Ciovati

Mechanical & Aerospace Engineering Faculty Publications

In support of the development of conduction-cooled superconducting radiofrequency (SRF) niobium cavities for use in continuous-wave linear accelerators, an experimental study of thermal contact resistance was performed on bolted joints using high-purity niobium, aluminium, and copper along with Apiezon N grease and indium foil as interfacial materials. The geometry of each joint investigated aims at replicating the design adopted in conduction-cooled SRF cavities currently under development at Jefferson Lab. The materials' thermal conductivity and the joints' thermal resistance were measured in the temperature range of 3.5 - 10 K. The results showed that the low thermal contact resistance of 2-4 …

A Computational Approach To Graduated Centrifuge Profiles For Partial Gravity Planetary Environments, Cabell W. Jones

Mechanical & Aerospace Engineering Faculty Publications

Missions such as NASA’s Artemis and SpaceX’s Starship aspire towards creating permanent settlements beyond Earth. In order to achieve this goal, it must be considered that the gravity present on planetary surfaces such as the Moon (0.165 g) and Mars (0.378 g) may be insufficient to support human physiology for long term habitation. On near-Earth missions, issues such as muscular atrophy, neuro-ocular changes, cardiopulmonary variations, and bone mineral density loss have been observed proportional to the duration spent in microgravity. Further studies have suggested that the severity of these conditions scales linearly with decreasing gravity, meaning that astronaut health can …

Stiffening Of Soft Silicone Upon Deep Uv Treatment As Characterized Using Nanoindentation, Amanda Wilder, Zaria Booth, Caden Obermeyer, Saika Sharmin, Venkat Maruthamuthu

Mechanical & Aerospace Engineering Faculty Publications

Silicones are elastomers that have a wide variety of uses, including biomedical applications such as the coating of biomedical devices and as implants. Soft silicones with mechanical properties similar to those of biological tissues have particularly gained use as substrates for cell culture in mechanobiology studies. In this context, it would be desirable to be able to alter their surface mechanical properties with a relatively simple physical treatment. While deep ultraviolet (deep UV) or ultraviolet C (UV-C) treatment has been previously used as a surface treatment method for stiffer silicones formulations, the effect of this treatment on soft silicones relevant …

A Combined Stochastic And Physical Framework For Alloys And Metal Casting Processes Modeling, Simon N. Lekakh, Oleg Neroslavsky

Materials Science and Engineering Faculty Research & Creative Works

High temperature metal casting processes have dualistic nature and conceptually consist of two parts of distinct processes: the first type is deterministic, strictly obeying the physical law, while the second type is stochastic. Therefore, the metal casting processes are not precisely predictable, and deterministic considerations cannot provide exact outcomes. To solve this problem, the combined stochastic and deterministic framework was suggested. The local processes were described using deterministic models for several parameter arrangements, while the distribution of these arrangements on macro level was calculated using stochastic approaches. The approach was used for cast alloy design, investment casting process optimization, and …

Thermal Transformations And Mechanical Properties Of All-D-Metal Mn2fecu Heusler-Type Shape Memory Alloy, Choji J. Daches, Joseph W. Newkirk, Mario Buchely

Materials Science and Engineering Faculty Research & Creative Works

All-d-metal Heusler alloys are emerging functional materials in which magnetic ordering, lattice distortion, and mechanical behavior are strongly coupled through d–d electronic interactions. This study systematically investigates the structural, thermal, magnetic, and mechanical properties of Mn₂FeCu synthesized within a Heusler-type compositional framework. SEM/EDS revealed a dual-phase FCC-based microstructure consisting of Mn–Fe–rich and Mn–Cu–rich domains, while XRD confirmed FCC symmetry with compositional partitioning rather than full L2₁ ordering. Differential scanning calorimetry identified partial melting of the Cu-rich phase near ~ 900 °C. Dilatometry showed a thermoelastic FCC → FCT transformation at ~ 770–780 °C with a recoverable strain of ~ 0.067%. …

Overcoming Resolution Vs. Throughput Trade-Offs In Ceramic Material Extrusion Additive Manufacturing Via Viscoelastic Filament Stretching, Abid H. Rafi, David W. Lipke, Jeremy L. Watts, Gregory E. Hilmas, Ming C. Leu

Materials Science and Engineering Faculty Research & Creative Works

Fabricating large, monolithic ceramic parts using material-extrusion additive manufacturing remains challenging due to difficulty maintaining uniform moisture content during printing, which can lead to drying-induced defects such as warping and cracking, especially as part size and print time increase. Fabricated parts have trade-offs among print resolution, high throughput, and structural fidelity. Our study has shown that increasing the ratio of nozzle traverse speed vs. material extrusion speed increases filament stretching in viscoelastic ceramic paste, helping to overcome the trade-offs between resolution and throughput. Using aqueous ZrB2–SiC (70/30 vol.%) as a representative ultra-high temperature ceramic paste, rheological characterisation revealed viscoelastic yield-stress …

Understanding Supply Chain Innovation, Kenneth B. Kahn, David P. Cook

Marketing Faculty Publications

Purpose – Supply chain innovation (SCI) represents a complex construct, capturing the interest of practitioners and researchers alike. There is no commonly accepted definition for the term, field research on the construct appears to be highly fragmented and industry examples demonstrate diverse ways in which it occurs.

Design/methodology/approach – Reviewing definitional literature and top winners of the Council of Supply Chain Management Professionals’ Supply Chain Innovation Award, this manuscript identifies salient points about SCI to guide continued research and industry practice.

Findings – Seven points are made about SCI. These pertain to its multiple definitions, technology, relationships, performance outcomes, conceptual …

Beauty Isn't Always Better: How Salesperson Attractiveness Affects Consumers' Approach Behaviors, Veronica L. Thomas, Stephanie M. Mangus, Dora E. Bock

Marketing Faculty Publications

This research examines how a consumer's committed romantic relationship influences their decision to approach an attractive salesperson in a retail environment. To date, the majority of research espouses the benefits of salesperson attractiveness in enhancing consumers' perceptions of the salesperson and the represented retailer. This is problematic because it creates a managerial bias toward attractive salespeople and, as we propose, provides an incomplete view of the effect of salesperson attractiveness on consumers' behavior. Drawing on the interpersonal relationship literature on commitment, we propose that consumers in committed relationships activate relationship-maintenance motives that override the beauty bias when a salesperson's attractiveness …

Ideational Behavior And Occupational Identity Achievement: A Study Of Emerging Adult College Students Preceding Entry Into The Fouth Industrial Revolution Workforce, Carrington M. Faulk, Michael F. Kosloski, Philip Reed

Marketing Faculty Publications

As emerging adults transition into the Fourth Industrial Revolution (4IR) workforce, it is essential to understand the factors that predict successful occupational identity achievement, as automation will impact human occupational identity crises. This descriptive cross-sectional study employed a correlational design to determine the degree to which ideational behavior predicts occupational identity achievement prior to entry into the 4IR workforce. Using a sample of 166 emerging adult college students from a Mid-Atlantic, diverse, four-year university, data were collected using Runco's Ideational Behavior Scale (RIBS) and Melgosa's Occupational Identity Achievement subscale (OIA). Results showed that ideational behavior significantly predicted occupational identity achievement …

A Case Study Of California Postsecondary Faculty Collaboration On Rubric Development To Foster Student Learning, Emmanuel Kwadwo Frimpong

Dissertations

Although perceived as the ‘gold standard’ strategy for conquering complex problems, collaboration can be ignored by intellectuals who prefer to work independently. This oversight may occur even in the face of challenging problems such as assessment of scholarships, institutional effectiveness, strategizing, and even the crafting of effective rubrics for assessing student learning. The scholarly literature clearly reveals that real difficulties often refuse to respond to routine assignments or common bureaucratic patterns. Additionally, 21st century conflicts may require creative solutions involving interdependence, joining of forces and brains, or vision sharing. Effective assessment of student learning within higher education may reflect just …

Math Anxiety, Math Self-Concept And Math Self-Efficacy: A Study Of The Jingle-Jangle Fallacies, Marsha Natasha Durrant-Walker

Dissertations

Problem

The overlap and lack of clear distinction among the constructs of math anxiety, math self-concept, and math self-efficacy presents issues for research and practice. The literature reveals that math anxiety is closely linked to math self-concept (Klee et al., 2022). Additionally, math self-concept and math self-efficacy often overlap and are not easily distinguishable (Kranzler & Pajares, 1997; Pajares & Miller, 1994; Pajares & Urdan, 1996). Each of these constructs has been shown to play a critical role in student math achievement (Timmerman et al., 2016). -- When constructs are not defined or measured distinctly, inconsistencies may emerge in research …

Exploring Lessons In Research: A Survey On Parental Perceptions Of Reading Opportunities, Laura Kettlehut

Dissertations

Problem

This exploratory study examines how parents’ past reading experiences relate to their perceptions of their children’s current reading opportunities across home and school contexts. Grounded in longstanding literacy research, the study explores how parent‑led, educator‑led, and child‑initiated reading experiences collectively shape children’s literacy development.

Method

Two research questions guided the inquiry: (1) How do parents perceive their own past reading opportunities? and (2) How do they perceive their children’s reading opportunities at home and in school? To address these questions, a 41‑item survey was developed and administered to parents of children enrolled in K–8 schools. The instrument measured two …

The Influence Of Black African American Fathers’ Parenting Styles On Young Adult Children’S Attachment Styles: The Roles Of Gender And Fathers’ Residence, Robert Baptiste Thompson

Dissertations

Parenting

Black African American (BAA) fathers in the United States are frequently mischaracterized as absent or uninvolved, reinforcing deficit-based narratives rooted in historical and systemic racism. Such portrayals obscure the meaningful and sustained roles many BAA fathers play in their families and fail to account for the cultural, structural, and contextual conditions that shape paternal involvement and parenting practices. Although a growing body of research has documented the importance of father involvement for child development, comparatively limited empirical attention has been given to how BAA fathers’ parenting styles influence their children’s attachment—particularly as a function of fathers’ co-residency histories. This …

Associating Emotional Intelligence, Cultural Intelligence, And Inclusive Leadership: A Correlational Study Of Seventh-Day Adventist Pastors And Church Leaders In Canada, Damson Anim Oppong

Dissertations

Problem

In an increasingly polarized world, church leaders are expected to foster inclusion, belonging, and unity within diverse congregations. Inclusive leadership (IL), supported by emotional intelligence (EQ) and cultural intelligence (CQ), may offer a relational leadership posture well-suited to this challenge. Growing evidence suggests that relational qualities such as EQ and CQ help leaders develop inclusive communities, foster belonging, and bridge differences (Thomas & Inkson, 2017; Wise, 2022). Emotional and cultural intelligence are studied increasingly in organizational settings, but little is known about how they affect inclusive leadership in faith-based institutions, such as among pastors and church leaders in the …

Teacher Self-Efficacy Perceptions For Technology Integration And Social Media Use As Instructional Tools: Future Implications For Pedagogy In Trinidad And Tobago, Paula Edwards Sealey

Dissertations

Problem

As the educational landscape in Trinidad and Tobago evolve post COVID-19, gaining an understanding of the purpose of teachers in the implementation of national and ministerial ICT policies seem imperative. The exploration of teacher’s personal belief about their ability to effectively infuse technology and social media with their traditional teaching practices, may provide much needed insight about the role that teacher self-efficacy plays in this educational shift (Caner & Aydin, 2021; Phillip & Cain, 2015). Very few studies in the local and regional literature involve teacher self-efficacy as a variable of interest. Moreso, there has been no research to …

Continuity And Development In The Eschatological Sabbath: Themes In Seventh-Day Adventist Thought (1842–2020), Joseph Nesbit

Dissertations

The Topic

This dissertation explores continuity and development in the eschatological understanding of the seventh-day Sabbath within selected Adventist theological writings from its Millerite origins to the contemporary scholarship of Jo Ann Davidson. The eschatological aspects of the Sabbath have played a central role in both pioneer and contemporary Adventist thought, particularly in its identification as the seal of God in Revelation and as a sign of covenant loyalty in the final crisis. While this understanding has displayed remarkable continuity in its essential themes, it has also undergone significant maturation in tone, scope, and theological emphasis. By tracing both enduring …

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 …

Validation Of The Touch/Bonding Sense Of The Five Senses Model Of Intimacy As A Spiritually Based Whole-Person Lifestyle Approach To Intimacy In Dating And Marital Relationships, Karen J. Holland

Dissertations

Problem

Intimacy is in crisis and is being culturally defined and redefined through a number of influencing factors. These include the ongoing development of individualist and narcissistic relationships; the fragmentation of human wholeness; the influence of social media and an increasingly entertainment focused society; the permeation of technology influencing personal choice and lifestyle, including the use of generative AI; and the diminishing influence of Judeo-Christian principles and values as key drivers in the development of life-long marriage relationships. This study seeks to address the need for establishing a foundation for relational intimacy based on the biblical relationship demonstrated by God’s …

A Phenomenological Qualitative Study Of The Experiences Of Board Chairs Toward Governance In Seventh-Day Adventist Schools Across Canada, Shad Lehmann

Dissertations

Problem

There is limited understanding of how school board chairs within the Canadian Seventh-day Adventist education system perceive and carry out their leadership and governance roles. The role of the board chair is complex, involving oversight of the organization, adherence to denominational policies, and alignment with the school’s academic and spiritual missions. Although effective governance is vital for school success, there remains a lack of clarity about how board chairs interpret their roles, fulfill their responsibilities, and navigate the unique demands of faith-based school leadership. This gap in understanding restricts the system’s ability to provide appropriate training, support, and clear …

Called To Lead: Leadership Journeys And Workplace Experiences Of Women Presidents In Seventh-Day Adventist Institutions, Gary Thurber

Dissertations

Problem

Although women constitute more than half of Seventh-day Adventist Church membership, they remain substantially underrepresented in senior leadership roles across North America. This disparity raises important questions about the historical, theological, organizational, and gender-related factors that shape women’s access to institutional leadership within the denomination. A growing body of scholarship has examined the life experiences of women clergy in the church; however, limited research has explored the experiences of women serving in presidential leadership roles within Seventh-day Adventist institutions.

Purpose

The purpose of this study was to understand and describe the experiences of women serving in presidential leadership roles …

The Desecration Of Sacred Spaces In The Dead Sea Scrolls And Pre-Nicene Latin Christianity: A History Of Interpretation Of The Eschatological Motif Of The Defiling Enemy In Apocalypticism, Rodrigo Galiza

Dissertations

Problem

The motif of the polluting enemy in the sanctuary is an important point of departure in the articulation of community boundaries in Hebraic-Christian culture. This particular motif has the potential to explain, at least in part, how Jewish and Christian communities would have understood the apocalyptic evil other and, from this understanding, set boundaries for their holy communities. Texts such as Dan 8 and 2 Thess 2 have been the locus classicus of the so-called antichrist, and ever since their interpretation has shaped how Christians and Jews have understood the enemy to their respective communities. In the history of …

Heat Misers, Snow Misers, And Cognitive Misers: The 'Nukewarm' Perceptions Of Nuclear Power, Tyler Williams

Dissertations and Theses

Rising energy demand in the United States necessitates alternatives to fossil fuels, yet renewable energy sources alone are insufficient to meet this demand. Nuclear power presents a promising option but faces persistent public hesitancy. This study examines how heuristic-based biases relate to American's risk-benefit perceptions towards nuclear power. Guided by the heuristic-systematic model. Results indicate that competence and affect are related to risk-benefit perceptions, and naturalness shows no relationship with risk perceptions but does correlate with benefit perceptions. Implications highlight the importance of affect-driven communication strategies for nuclear communicators, while also underscoring the need for participatory approaches that foster trust …

Rethinking Dfw In Gateway Mathematics: Preserved, Disrupted, And Dissipated Momentum Pathways To Student Retention, John Alan Nunnery, Charles Mathies

Educational Leadership & Workforce Development Faculty Publications

This study examines how disaggregated first-year mathematics outcomes, including failure, low-passing grades, course withdrawal, and no attempt at a credit-bearing mathematics course, are associated with second-year retention at a large, diverse, urban public university. The study extends academic momentum theory by positing and operationalizing preserved (marginal passing), disrupted (failure or withdrawal), and dissipated (non-enrollment) as qualitatively distinct momentum states rather than a single condition. Using a segmented binary logistic regression model with more than 26,000 first-time, full-time students across ten entry cohorts (2012–2021), we estimate differences in retention by mathematics outcome, course type, and cohort context. Results show a pronounced …