Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
Displaying 101 - 108 of 108
ContributorsBuessing, Robert (Author) / Nian, Qiong (Thesis director) / Zhuang, Houlong (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2022-05
Description
Over the past several decades, middle-aged Americans have exhibited troubling trends of declining mental and physical health over successive cohorts. Interestingly, this trend has not been observed in peer nations in Europe, Asia, and Mexico. Later-born cohorts in other countries typically report better midlife mental and physical health than their earlier-born counterparts. It is less clear the extent to which physical pain shows similar trends to what has been observed in the U.S. and comparison peer nations. The goal of the current study was to examine how self-reports of pain have historically changed during midlife and investigate whether differences emerge between the U.S. and peer nations. We used harmonized data on pain from nationally representative longitudinal panel surveys from the U.S., 13 European nations, South Korea, and Mexico to directly quantify similarities and differences in historical change in midlife pain. Our results supported the hypothesis that midlife pain is higher amongst later-born cohorts in the U.S. A similar pattern of historical increases in pain was observed in Continental and Nordic Europe. In England, Mediterranean Europe, South Korea, and Mexico, the opposite pattern was observed with historical declines in pain. Historical increases in reports of pain in the U.S. emerged more quickly for later-born cohorts at earlier stages of midlife. These results suggest there could be aspects of American midlife today that are exacerbating reports of pain, and these aspects may be shared in some European nations but absent or less influential in other peer nations. Our discussion focuses on potential explanations for this pattern, such as population level discrepancies in health, differential use of health care services, and the inter/intrapersonal costs of westernization, as well as how pain is conceptualized across nations.
ContributorsSyed, Orchee (Author) / Infurna, Frank (Thesis director) / Corbin, William (Committee member) / Davis, Mary (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / Sanford School of Social and Family Dynamics (Contributor)
Created2023-12
Description
Previous evidence implicating fighting gameplay with markers for cardiovascular changes in response to stress appraisals emphasizes the plausibility of additional biopsychosocial factors varying between players and dictating gameplay changes (Porter & Goolkasian, 2019). The current study builds upon previous research using the Biopsychosocial Model of Challenge and Threat (Blascovich and Tomaka, 1996) alongside the Mental Load Rating Scale (Hughes, 2023) to link perceptions of increased stress during gameplay with increases in gameplay errors. Participants were allotted a set time to acclimate to fighting game mechanics, then began combo trials. The game used in research (Street Fighter 6) requires precise movements in rapid succession completion the completion of a “combo”. Competitive fighting game players were compared to players lacking fighting game experience in post-participation response measuring stress salience or hindrance perception, as well as total input error comparison. Current findings suggest Competitive fighting game players report factors such as spectator viewing and time limits as hindrances capable of being overcome as opposed to Noncompetitor reports of factors and stressors during game acclimation. Findings between Competitor and Noncompetitor groups allude to cultural significance when navigating gameplay. Future research should continue measuring sociocultural perception of stress when navigating specific genres of video game play and avenues for stress reappraisal techniques.
ContributorsDavis, Nicholas (Author) / Holloway, Steven (Thesis director) / Flores, Valerie (Committee member) / Davis, Mary (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)
Created2023-12
Description
Approximately 20% of youth experience mental health problems (Vasileva et al., 2021), and dimensions of early childhood temperament, specifically negative affectivity and effortful control, predict later mental health (Rothbart, 2007). Examining temperament using person-centered methods, particularly in stressful contexts, may improve our understanding of vulnerability to adolescent emotional problems. The current study examined whether specific patterns, or types, of infant temperament longitudinally predicted adolescent anxiety and depression symptoms and whether family relationship stress moderated this association. We hypothesized that infants with a Negative Dysregulated temperament would experience higher anxiety and depression symptoms in later childhood compared to those with a Typical Expressive temperament, and that family relationship stress would exacerbate this link. In an ongoing-longitudinal study of families with twins (N=563, 51% female, 29.8% Hispanic/Latinx, 58.4% White; Lemery-Chalfant et al., 2019), primary caregivers (PCs) reported on infant temperament at 12 months (IBQ; Gartstein & Rothbart, 2003, α=.74-.90). In a prior study (Murillo et al., 2023), latent profile analysis yielded three infant temperament types: Negative Dysregulated, Positive Well-Regulated, and Typical Expressive. PCs reported on partner strain (PSS; Schuster, Kessler, & Asseltine, 1990, α=.87) and family conflict (FCS; Porter & O’Leary, 1980, α=.80) at age 8 and a composite of these two measures represented Family Relationship Stress (r = .689). Confirmatory factor analysis was used to form Depression and Anxiety outcome composites based on PC (4 reports), secondary caregiver (2 reports), teacher (2 reports), and self-report (3 reports) measures of depression and anxiety symptoms collected from ages 8-11 (HBQ, Armstrong & Goldstein, 2003; BPI, Measelle et al., 1998, all α’s > .80). We randomly selected one twin from each pair and conducted regression analyses, and then used the second twin for an internal replication. Family relationship stress had a significant main effect on both anxiety and depressive symptoms. The Negative Dysregulated temperament type did not predict anxiety and depression at ages 8-11, however, it interacted with family relationship stress to predict anxiety and depression in 1 of 2 samples. When family relationship stress was low, the Negative Dysregulated type was significantly associated with higher anxiety and depression outcomes compared to the Typical Expressive type, and high family relationship stress was significantly associated with lower depression outcomes. Elucidating these longitudinal relations is important for informing early intervention and reducing the burden of adolescent psychopathology.
ContributorsSingh, Ajuni (Author) / Lemery-Chalfant, Kathryn (Thesis director) / Corbin, William (Committee member) / Davis, Mary (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / Sanford School of Social and Family Dynamics (Contributor)
Created2023-12
Description
Research on self-regulatory variables like mindfulness and effortful control proposes strong links with physical and mental health outcomes across the lifespan, from childhood and adolescence to adulthood and old age. One pathway by which self-regulation may confer health benefits is through individual differences in reports of and emotional responses to daily negative and positive events. Mindfulness is broadly defined as non-reactivity to inner experiences, while effortful control is broadly defined as attentional and behavioral regulation. Mindfulness and effortful control have both been conceptualized to exert their beneficial effects on development through their influence on exposure/engagement and emotional reactivity/responsiveness to both negative and positive events, yet few empirical studies have tested this claim using daily-diary designs, a research methodology that permits for examining this process. With a sample of community-dwelling adults (n=191), this thesis examined whether dispositional mindfulness (i.e., non-reactivity of inner experience) and effortful control (i.e., attention and behavioral regulation) modulate reports of and affective reactivity/responsiveness to daily negative and positive events across 30 days. Results showed that mindfulness and effortful control were each associated with reduced exposure to daily stressors but not positive events. They also showed that mindfulness and effortful control, respectively, predicted smaller decreases in negative affect and smaller increases in positive affect on days that positive events occurred. Overall, these findings offer insight into how these self-regulatory factors operate in the context of middle-aged adults’ everyday life.
ContributorsCastro, Saul (Author) / Infurna, Frank (Thesis advisor) / Doane, Leah (Committee member) / Davis, Mary (Committee member) / Arizona State University (Publisher)
Created2018
Description
Janus Transition Metal Dichalcogenides (TMDs) are emerging 2D quantum materials with an asymmetric chalcogen configuration that induces an out-of-plane dipole moment. Their synthesis has been a limiting factor in exploring these systems' many-body physics and interactions. This dissertation examines the challenges associated with synthesis and charts the excitonic landscape of Janus crystals by proposing the development of the Selective Epitaxy and Atomic Replacement (SEAR) technique. SEAR utilizes ionized radical precursors to modify TMD monolayers into their Janus counterparts selectively. The synthesis is coupled with optical spectroscopy and monitored in real-time, enabling precise control of reaction kinetics and the structural evolution of Janus TMDs. The results demonstrate the synthesis of Janus TMDs at ambient temperatures, reducing defects and preserving the structural integrity with the hitherto best-reported exciton linewidth emission value, indicating ultra-high optical quality. Cryogenic optical spectroscopy (4K) coupled with a magnetic field on Janus monolayers has allowed the isolation of excitonic transitions and the identification of charged exciton complexes. Further study into macroscopic and microscopic defects reveals that structural asymmetry results in the spontaneous formation of 2D Janus Nanoscrolls from an in-plane strain. The chalcogen arrangement in these structures dictates two types of scrolling dynamics that form Archimedean or inverted C-scrolls. High-resolution scanning transmission electron microscopy of these superlattices shows a preferential orientation of scrolling and formation of Moiré patterns. These materials' thermodynamically favorable defect states are identified and shown to be optically active. The encapsulation of Janus TMDs with hexagonal Boron Nitride (h-BN) has allowed isolation defect transitions. DFT coupled with power-dependent PL spectroscopy at 4K shows the broad defect band to be a convolution of individual defect states with extremely narrow linewidth (2 meV) indicative of a two-state quantum system. The research presents a comprehensive synthesis approach with insights into the structural and morphological stability of 2D Janus layers, establishing a complete structure-property correlation of optical transitions and defect states, broadening the scope for practical applications in quantum information technologies.
ContributorsSayyad, Mohammed Yasir (Author) / Tongay, Sefaattin (Thesis advisor) / Esqueda, Ivan S (Committee member) / Zhuang, Houlong (Committee member) / Arizona State University (Publisher)
Created2024
Description
In the age of 5th and upcoming 6th generation fighter aircraft one key proponent of these impressive machines is the inclusion of stealth. This inclusion is demonstrated by thoughtful design pertaining to the shape of the aircraft and rigorous material selection. Both criteria aim to minimize the radar cross section of these aircraft over a wide bandwidth of frequencies corresponding to an ever-evolving field of radar technology. Stealth is both an offensive and defensive capability meaning that service men and women depend on this feature to carry out their missions, and to return home safely. The goal of this paper is to introduce a novel method to designing disordered two-phase composites with desired electromagnetic properties. This task is accomplished by employing the spatial point correlation function, specifically at the two-point level. Effective at describing the dispersion of phases within a two-phase system, the two-point correlation function serves as a statistical function that becomes a realizable target for heterogeneous composites. Simulated annealing is exercised to reconstruct two-phase composite microstructures that initially do not match their target function, followed by two separate experiments aimed at studying the impact of the provided inputs on its outcome. Once conditions for reconstructing highly accurate microstructures are identified, modifications are made to the target function to extract and compare dielectric constants associated with each microstructure. Both the real and imaginary components, which respectively affect wave propagation and attenuation, of the dielectric constants are plotted to illustrate their behavior with increasing wavenumber. Conclusions suggest that favorable values of the complex dielectric constant can be reverse-engineered via careful consideration of the two-point correlation function. Subsequently, corresponding microstructures of the composite can be simulated and then produced through 3-D printing for testing and practical applications.
ContributorsPlantz, Alex Chadewick (Author) / Jiao, Yang (Thesis advisor) / Zhuang, Houlong (Committee member) / Yang, Sui (Committee member) / Arizona State University (Publisher)
Created2024
Description
This dissertation contributes to uncertainty-aware neural networks using multi-modality data, with a focus on industrial and aviation applications. Drawing from seminal works in recent years that have significantly advanced the field, this dissertation develops techniques for incorporating uncertainty estimation and leveraging multi-modality information into neural networks for tasks such as fault detection and environmental perception. The escalating complexity of data in engineering contexts demands models that predict accurately and quantify uncertainty in these predictions. The methods proposed in this document utilize various techniques, including Bayesian Deep Learning, multi-task regularization and feature fusion, and efficient use of unlabeled data. Popular methods of uncertainty quantification are analyzed empirically to derive important insights on their use in real world engineering problems. The primary objective is to develop and refine Bayesian neural network models for enhanced predictive accuracy and decision support in engineering. This involves exploring novel architectures, regularization methods, and data fusion techniques. Significant attention is given to data handling challenges in deep learning, particularly in the context of quality inspection systems. The research integrates deep learning with vision systems for engineering risk assessment and decision support tasks, and introduces two novel benchmark datasets designed for semantic segmentation and classification tasks. Additionally, the dissertation delves into RGB-Depth data fusion for pipeline defect detection and the use of semi-supervised learning algorithms for manufacturing inspection tasks with imaging data. The dissertation contributes to bridging the gap between advanced statistical methods and practical engineering applications.
ContributorsRathnakumar, Rahul (Author) / Liu, Yongming (Thesis advisor) / Yan, Hao (Committee member) / Jayasuriya, Suren (Committee member) / Zhuang, Houlong (Committee member) / Kwon, Beomjin (Committee member) / Arizona State University (Publisher)
Created2024