Dissertation Defense Announcements

Candidate Name: Richard James Gerdts II
Title: The Dark Side of Entrepreneurship Meets the Dark Triad: Entrepreneurial Passion, Work Addiction, and Personality Traits
 April 05, 2022  12:00 PM
Location: Virtual

Passion can drive entrepreneurs to new heights of success and fulfilment, but the dark side can also lead to conflict with relationships and activities. Work addiction goes a step further as it demands the entrepreneur’s time and energy even when they are off the clock. This study explores the relationship between entrepreneurial passion and work addiction, leaning on the Dualistic Model of Passion. It also investigates the possibility that personality traits influence this connection. Empirical evidence suggests that obsessively passionate entrepreneurs are more likely to encounter work addiction than their less passionate counterparts. The data also supports a weak link between harmonious entrepreneurial passion and work addiction, with harmoniously passionate entrepreneurs being less susceptible to work addiction. Finally, there was minimal support for the idea that the Dark Triad traits (narcissism, Machiavellianism, psychopathy) play a role in this exchange. There is a secondary nuance to this study regarding passion and addiction. It provides evidence that passion with one target can relate to addiction with another. This encourages the examination of other cross-target passion and addiction relationships.

Candidate Name: Courtney S. Green
Title: Persistence of Engineering Transfer Students: Identifying Student-Influenced and Institution-Influenced Academic Success Factors
 April 08, 2022  11:00 AM
Location: virtual

This correlational study utilized secondary, longitudinal data to examine the extent to which student-influenced and institution-influenced factors predict the academic success and degree completion of engineering transfer students at public four-year institutions in North Carolina. The sample included students who transferred from community colleges to pursue baccalaureate degrees at UNC System institutions that offered engineering or engineering technology programs from 2009 to 2016. Based on the data structure, regression analyses were utilized to examine the factors that predict first-semester academic performance and persistence to degree attainment at the receiving institutions. The hierarchical organization of student-influenced, institution-influenced, and both student and institution-influenced factors were based on a modified version of Smith and Van Aken’s (2020) literature-based conceptual framework on engineering transfer student persistence.

Results indicated that first-term academic performance is impacted by student background, college/department of engineering characteristics, and attempted and earned hours in the first semester. Further, persistence was affected by age, the amount of transfer credit, college/department of engineering characteristics, and cumulative GPA and total earned hours at the receiving institution by the student. This study provides practical and actionable findings that will aid four-year engineering institutions in increasing the academic success and persistence of vertical transfer students pursuing baccalaureate engineering degrees.

Please email me at csgreen2@gmail.com for the Zoom link if you would like to attend.

Candidate Name: Bryndle Laine Bottoms
Title: A Systematic Approach to Interrater Reliability in Teacher Performance Evaluations
 April 05, 2022  2:30 PM
Location: Zoom

Teacher evaluations are routinely conducted across the United States for licensure and professional development supports. However, there is limited research on the interrater reliability of these evaluation assessment systems, despite federal recommendations (Graham et al., 2012). This research explores the systematic approach to interrater reliability utilized by the Early Educator Support (EES) Office in North Carolina. The EES Office supports the Birth-through-Kindergarten (B-K) teacher licensure of over 900 early educators in both private and public sectors. The evaluators employed undergo extensive trainings and hold a B-K license themselves. As part of the training, the evaluators undergo an interrater reliability activity that requires them to rate ten fictitious profiles, using the North Carolina Teacher Evaluation Process (NCTEP) Rubric. This research aims to understand the evaluator response process. In this study, Many Facets Rasch Models are used to understand evaluator patterns of strictness, leniency and potential bias based on the race of teacher profile. Additionally, two of the models are compared to understand the extent that these rater response patterns are exhibited in their real caseloads of actual early educators. In conclusion, the group of evaluators do show evidence of strictness, leniency, and bias, however it is mostly exhibited by a small number of individual evaluators. It is possible to use the results to inform the professional growth of these evaluators, so that all early educators served by the EES Office receive valid, fair, and reliable teacher evaluations. Furthermore, it depicts a systematic approach to interrater reliability that could be used by other evaluation systems across the country.

 April 01, 2022  1:30 PM
Location: Zoom Meeting https://uncc.zoom.us/j/95668169625?pwd=Q1c0YUhMVTFycmFJTVFzWWNKaHFrdz09

Turnover in is a critically important issue as organizations seek to retain quality personnel in the face of shortages in skilled and experienced labor. However, prior research in the area has been limited and produced mixed results, which may be in part due to difficulties in operationalizing related constructs and moderators. In addition, the COVID-19 pandemic caused an unprecedented employment crisis all around the world. The study is built on the premise that when employees feel that their interests are protected, and support is given to them, they will have a positive response in return. As such, this study, grounded in social exchange and reciprocity norm theories, will seek to provide additional evidence on the relationship between Perceived Organization Support and Job Embeddedness on turnover intention. Second, this dissertation will provide insight into how employees’ perception of COVID-19 has had on the forementioned constructs and employees’ productivity. Third, the study seeks to verify the moderating effect of gender, age, and ethnicity. This study seeks to understand how employees’ perceptions of the organization and their connections to their job influences their turnover intentions. This paper utilizes survey data collected from employees in various industries including accounting. While the results did not confirm interaction effects from the demographic tested, the results did affirm the impact of Perceived Organization Support and Job Embeddedness on turnover intention. Results also provided evidence of the impact of the stress related to and fear of COVID-19 to turnover intention and the impact of benefits use and benefits needed on Perceived Organizational Support. These findings extend prior research on the role organization policies and practices impact turnover intention outcomes.

Candidate Name: LaShana M. Wiggs
Title: The Credibility of Racial Justice Statements: The Impact of Charisma and Race
 March 30, 2022  10:00 AM
Location: Friday Building Conference Room 222

Recent events in society have brought racial justice to the forefront of conversations and have prompted companies to issue statements on their stance on racial justice in America. These statements have been pervasive, with many companies touting their support for diversity, equity, and inclusion in their organizations and society at large. However, little is known regarding whether a stakeholder finds these statements as credible or not. This research empirically examined the perceived credibility of racial justice statements assessing the impact of race and use of charismatic leadership tactics (CLTs) in messages. A 2 (high charisma vs. low charisma) x 2 (White leader vs. BIPOC leader) experimental design was used to survey (N=1200) participants for their evaluation of racial justice statements. I found that across all conditions CLT usage significantly influenced message credibility for White and BIPOC leaders as well as White and BIPOC stakeholders. Theoretical and practical implications, limitations and future research are discussed.

Candidate Name: Jatnna Acosta
Title: The T is Silent: An Autoethnographic Portrayal of Latinx Teacher Identity Development and Consciousness
 April 04, 2022  12:00 PM
Location: Virtual

Despite evidence of the rapid growth of Latinx students throughout the country (Gándara, 2017; He & Yu, 2017), there has been inadequate critical examination of the educational policies and practices impacting this population and their self-identification. Teachers play a crucial role in ensuring that all students, regardless of cultural or linguistic background, receive a quality education that will equip them for post-school success in an increasingly diverse society. Studies suggest that teachers who share the racial, cultural, and/or ethnic identity of their students can play an important role in their success. Unfortunately, Latinx teachers remain starkly underrepresented within the field (Shapiro & Partelow, 2018), even though Latinx teacher representation plays a critical role in not only the academic achievement of Latinx students but is also prevalent in the solving of larger issues related to ethnic and racial identity development and consciousness (Goldhaber et al., 2019) because of the postcolonial structures in schools. Postcolonial structures are implicated by the structural inequality and racial and economic disparities that continue to plague racialized groups throughout society. In order to fulfill this role, Latinx teachers need to richly understand their Latinx identity development and consciousness.

The purpose of this autoethnographic study was to systematically examine and reflect on my lived experiences as an immigrant in the United States to better understand Latinx identity development and consciousness and the role of Latinx teachers in combating the exclusionary practices of postcolonial structures in schooling. Using Latinx Critical Theory (LatCrit) as the theoretical framework, this dissertation focuses on Latinx teachers and the impact of identity development on their role in the classroom. I examined my Latinx identity at different stages of my life and positioned this within the collective experiences of other Latinx teachers to better understand the factors that have contributed to my evaluation of self.

The data collected for this study consisted of a life timeline, transcribed journals I kept throughout my teaching career, cultural artifacts, and an individual autobiographical narrative. This highly reflective process was then analyzed thematically to identify themes and patterns that emerged from the data. The findings revealed three major themes: ongoing identity detachment, Latinx imposter syndrome, and unveiled hypocrisy in education. Ongoing identity detachment highlights my continued loss of identity. Latinx imposter syndrome depicts the feelings of doubt, fear, and fraud I had to overcome in my role as a bilingual teacher of emergent bilingual students. Lastly, unveiled hypocrisy in education captures my awareness and understanding of the marginalization and exclusion within the education system. This study has significant implications for the understanding of Latinx teacher identity development and the influence their self-perception has on their work within the classroom. Recommendations on how to further the discussion on identity development and consciousness and the role of Latinx teachers in combating the exclusionary practices of postcolonial structures in schooling are made to teacher preparation programs, school and district leaders, Latinx teachers, and for future research.

Keywords: postcolonial structures, raciolinguistic ideologies, internalized oppression, immigrant experience, Latinx teacher identity

Candidate Name: Xiaoyun Chen
Title: The general non-stationary Anderson Parabolic Model with correlated white noise
 March 29, 2022  2:00 PM
Location: Online via Zoom

This dissertation contains the analysis of the general lattice non-stationary Anderson parabolic model with correlated white noise. It starts form the brief description of known results about parabolic problem with local Laplacian and the detailed description of the general non-local Anderson model in the non-stationary random environment (Chapter 2). Chapter 3 is devoted to existence-uniqueness theorems for the parabolic model in the weighted Hilbert space and the solution in Feynman–Kac formula representation. The chapter 4 contains the results on the first and second moments of the solution and the spectral properties of the Hamiltonian $\mathcal{H}_2$, providing the basic information on the phase transition of the model from the regular to intermittent structure, additional results concerns the other spectral bifurcations of $\mathcal{H}_2$.

Candidate Name: Zheng Li
Title: Constitutive Modeling and Dynamic Impact Analysis of Bighorn Sheep Horn
 March 30, 2022  2:00 PM
Location: DUKE 308

Bighorn sheep (Ovis canadensis) is known for its giant spiral horns that can sustain impact loading at a speed up to 5.5 m/s during ramming without causing severe damage or head concussion. The bighorn sheep horn was composed of a keratin-based biological material with a tubule-lamella structure. This special structure gives the anisotropic hardening characteristics of the horn material under impact loading. Investigating the mechanisms of energy dissipation of the bighorn sheep horns could inspire the design and development of artificial materials with high capacity of energy dissipation and/or impact mitigation.

In this study, a transversely isotropic constitutive model with anisotropic hardening and strain-rate effects was developed for predicting the mechanical responses of the horn under impact loading. The characterization of material properties was conducted using test data from uniaxial compression tests of the horns under both quasi-static and dynamic loadings. The constitutive model was later implemented into the commercial finite element code, LS-Dyna, as user-defined material subroutine and was successfully validated against test results. Finite element simulation was conducted on the dynamic impact against the bighorn sheep horn and the user-defined constitutive model was used to study the mechanical responses of the horn material that was under large impact loads without severe damage. The mechanism of energy dissipation was also investigated from energy absorption and conversion, stress distributions, and propagation of displacement waves.

Candidate Name: Yikai Jia
Title: Multiphysics nature of Lithium-ion Battery safety issues
 April 01, 2022  1:30 PM
Location: Duke 324

Safety issues of lithium-ion batteries (LIBs) are usually initiated from an internal short circuit (ISC) that can be triggered by external accidental abusive loadings. The generated heat and the increased temperature would lead to several complicated physio-chemical changes of the batteries, e.g., thermal runaway (TR). Thus, investigation of the multiphysics behaviors of lithium-ion batteries becomes a paramount task to understand the battery safety issues. Experimental characterization and numerical simulation are essential ways to understand the underlying nature of the multiphysics behavior of batteries. However, experimental observation may only provide insufficient data due to the limitation of experimental technology. Particularly, in-situ and operando experiment methodologies are limited. Multiphysics modeling is regarded as a critical and insightful tool to unravel the nonlinear and complicated behaviors. Machine learning (ML) model with data-driven methodology is another important tool to realize fast and accurate estimation and classification. Herein, an ML-based ISC risk evaluation model will be first developed based on the training dataset generated by the combination of experimental data and simulation data. A Representative Volume Element (RVE) based mechanical model, which can predict accurate mechanical behaviors at a much lower calculation time cost, will be established to assist the data generation. Next, an ML-based classifier will be developed to classify the cell’s safety levels under various work conditions. A multiphysics model will be developed to assist the generation of training data samples. Finally, two typical safety issues: defect and TR propagation are systematically studied. The safety risk of the defective batteries will be further evaluated. Electrochemical and mechanical characterization tests will be designed and conducted. The multiphysics model will be used to provide necessary auxiliary instructions of the related mechanisms. TR propagation behaviors of battery packs will be experimentally and numerically investigated. The battery pack TR model will be developed based on the single-cell multiphysics model.
This study comprehensively investigates the multiphysics behavior of LIB cells under mechanical abusive loadings, highlights the promise of combining the physical model with a data-driven model, and provides an innovative solution for the recognition of the battery safety risks for battery safety monitoring.

Candidate Name: Jacob Cole
Title: Characterization of Surfaces by X-Ray Reflectometry
 March 31, 2022  10:00 AM
Location: Duke 106A, Zoom https://uncc.zoom.us/j/95090807593?pwd=blQxaXNJUFVTY2NIQzVGR1VBVExEZz09

X-ray reflectometry (XRR) is a highly used tool for the measurement of semiconductor and other high-performance surfaces. This work presents novel models and methods for the evaluation of surfaces having geometries that have not been addressed previously.

A model and experimental procedure are developed to determine the effect that mid-spatial frequency errors have on the x-ray reflectivity of optics. This model is used to simultaneously determine the surface roughness and waviness of surfaces; greatly extending the breadth of XRR. To evaluate this model, borosilicate glass optics were magnetorheologically polished to have waviness features of 100 nm peak-valley and spatial wavelength 4 mm/cycle. XRR measurements of these samples predicted the high-frequency surface roughness and the mid-spatial frequency waviness as measured by atomic force microscopy (AFM) and Fizeau interferometry with sub-nanometer accuracy.

Additionally, a comprehensive model for the evaluation of surface roughness of curved surfaces using XRR is developed. This work extends XRR as a technique for evaluating the surface roughness of external and internal surfaces of cylinders and spherical shells. Experimental measurements using thin polished silicon wafers that were bent using a specialized flexure-based fixture to various radii and the predicted RMS roughness from XRR is compared with AFM measurements.