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ContributorsASU Library. Music Library (Publisher)
Created2021-11-21
Description
Given the prevalence and severity of dating violence (DV) in our World, uncovering the long-term effects of DV is pivotal. This thesis provides information about how prior DV impacts a survivor’s future relationships. First, understanding the association between prior DV and current relationship satisfaction. Next, suggesting potential moderators between DV and current relationship satisfaction in forms of resilience. Tangible resilience strategies such as seeking therapy and obtaining an order of protection were assessed as potential moderators. As well as one’s attachment style as a predictor of how one overcomes prior DV and impacts current relationship satisfaction. A study was conducted with 218 participants from both the United States and international countries. Prior DV was a predictor of relationship satisfaction, however in the adverse way as predicted. Survivors of prior dating violence reported higher levels of current relationship satisfaction. Tangible resilience and secure attachment style were both significant moderators of the relationship between prior DV and current relationship satisfaction. These results present new ways to face the challenge of overcoming the repercussions of DV for survivors. As well as provide hope and support to all survivors of DV that their past does not have to impact their future.
ContributorsGraham, Kaylyn (Author) / Mickelson, Kristin (Thesis advisor) / Randall, Ashley (Committee member) / Burleson, Mary (Committee member) / Arizona State University (Publisher)
Created2022
Description
Modern aircraft propulsion systems such as the ultra high bypass ratio turbofan impose constraints on engine installation below the wing, causing jet–wing interactions. Similar interactions are encountered when a jet-powered aircraft takes off on airport runway or aircraft carrier deck. High-speed jet flow near a solid surface shows markedly different turbulence characteristics compared with free jet, including attached turbulent jet and development of non-equilibrium boundary layer down- stream. Wall pressure fluctuations tend to be more unsteady and stronger, leading to increased vibration affecting aircraft cabin noise and modified jet noise radiation. Large-eddy simulation (LES) is useful to characterize turbulent jet flows over a solid surface as well as wall pressure distribution to promote physical understanding and modeling studies. In this study, LES is performed for an installed setup of a Mach 0.7 turbulent jet where the jet–plate distance is fixed at 2D where D is the nozzle-exit diameter. Unstructured-grid LES is used to validate the corresponding experiment (from literature). In addition, a high-fidelity numerical database is built for further analysis and modeling. Turbulence statistics and energy spectra show that agreement with the experimental measurement for the installed case is encouraging, paving a way for future analysis and modeling.
ContributorsTamhane, Nikhil (Author) / Kim, Jeongale (Thesis advisor) / Peet, Yulia (Thesis advisor) / Jeun, Jinah (Committee member) / Arizona State University (Publisher)
Created2022
Description
Given the emergence of social media over the past decade and its popularity with adolescents, understanding its impact on this population is crucial to investigate. The purpose of this thesis was to identify potential links between social media use, identity formation, self-esteem, and social comparison motives. The first hypothesis proposed a positive association between passive social media use and identity moratorium, diffusion, and distress. The second hypothesis suggested self-esteem would mediate this relationship. The final hypothesis posited that the social comparison motives of self-destruction and self-evaluation would exacerbate negative influences of social media use on self-esteem and identity, while self-enhancement and self-improvement motives would buffer them. Two studies were conducted, one observational with 568 participants and one experimental with 15 participants. The first study found active social media use significantly predicted identity diffusion and distress, whereas the second study determined passive social media use led to identity distress. Self-esteem was not found to mediate either relationship. Finally, self-destruction, self-enhancement, self-evaluation, and self-improvement all had differing moderating effects on social media use and the distinct identity outcomes and self-esteem. These results introduce a new concern for late adolescents still developing their identities who utilize social media, as having an online presence can further impede commitment to an identity.
ContributorsCaldera, Karla (Author) / Mickelson, Kristin D (Thesis advisor) / Hall, Deborah (Committee member) / DeLay, Dawn (Committee member) / Arizona State University (Publisher)
Created2022
Description
Nanostructured (NS, grain size (d) <100nm) and ultrafine grained (UFG, d<500nm) metals possess superior mechanical and electrical properties over coarse grained (CG, d≫1μm) metals. The strength of metals like copper (Cu) has been shown to be significantly improved when engineered to have fine and ultrafine grain sizes via processes such as cryomilling, Cold Isostatic Pressing (CIP) and Continuous Equal Channel Angular Pressing (C-ECAP). This study investigates the mechanical and electrical properties of laboratory scale copper (Cu) conductors manufactured through several steps including cryomilling followed by cold isostatic pressing and finally C-ECAP and how its strength is affected by a variety of parameters when tested in uniaxial tension. The copper material is fabricated through cryomilling, cold isostatic pressing and (C-ECAP). Mechanical characterization is conducted using uniaxial tensile tests, nanoindentation and hardness tests. Pre and Post fabrication examination of the material with 3D-xray tomography, optical and electron microscope were conducted to gain deeper understanding of the effects of the processing parameters on the material during fabrication and the evolution of the microstructure as the powders go through the manufacturing process. Electrical testing is conducted to evaluate the electrical conductivity of the manufactured copper.
While the material showed improved strength and hardness compared to conventional copper material at room temperature, its ductility decreased. Also, higher ECAP temperatures produced materials with higher electrical and mechanical properties.
ContributorsOpoku, Jackson Abankwa (Author) / Ladani, Leila LJL (Thesis advisor) / Razmi, Jafar JR (Committee member) / Li, Xiangjia XL (Committee member) / Arizona State University (Publisher)
Created2022
Description
Material behavior under high strain rate deformation has always been an interesting topic. Under this extreme impact, possible structure changes such as phase transformation, chemical reaction, and densification occur in materials. It is helpful to develop a fundamental understanding of structure-property relationship, which helps to build a theoretical model and speed up the material design process. Although shock experiment techniques have been widely developed, numerical approaches such as first principle calculations and molecular dynamics simulations have demonstrated their power in predicting shock behavior and revealing structure-property relationship in an economic and feasible manner. In this dissertation, the mechanical properties and shock responses of three materials, polyurea, silicate glass, and erythritol were investigated, among which polyurea and silicate glass are proposed to be protective materials, while erythritol is proposedto be a surrogate of the explosive material pentaerythritol tetranitrate. First principle calculations and classical molecular dynamics were carried out to predict the shock Hugoniot, and other thermomechanical properties. The simulations also explored potential shock-induced phase transformations in these three materials and seek to draw connections between shock-driven transformations and the underlying chemical composition and material structure.
composition and material structure.
ContributorsHu, Jing (Author) / Oswald, Jay JO (Thesis advisor) / Muhich, Christopher CM (Committee member) / Zhuang, Houlong HZ (Committee member) / Solanki, Kiran KS (Committee member) / Peralta, Pedro PP (Committee member) / Arizona State University (Publisher)
Created2022
Description
Vanadium-dioxide-based devices show great switchability in their optical properties due to its dramatic thermochromic phase transition from insulator to metal, but generally have concerns due to its relatively high transition temperature at 68 °C. Doping the vanadium dioxide with tungsten has been shown to reduce its transition temperature at the cost lower optical property differences between its insulating and metallic phases. A recipe is developed through parametric experimentation to fabricate tungsten-doped vanadium dioxide consisting of a novel dual target co-sputtering deposition, a furnace oxidation process, and a post-oxidation annealing process. The transmittance spectra of the resulting films are measured via Fourier-transform infrared spectroscopy at different temperatures to confirm the lowered transition temperature and analyze their thermal-optical hysteresis behavior through the transition temperature range. Afterwards, the optical properties of undoped sputtered vanadium films are modeled and effective medium theory is used to explain the effect of tungsten dopants on the observed transmittance decrease of doped vanadium dioxide. The optical modeling is used to predict the performance of tungsten-doped vanadium dioxide devices, in particular a Fabry-Perot infrared emitter and a nanophotonic infrared transmission filter. Both devices show great promise in their optical properties despite a slight performance decrease from the tungsten doping. These results serve to illustrate the excellent performance of the co-sputtered tungsten-doped vanadium dioxide films.
ContributorsChao, Jeremy (Author) / Wang, Liping (Thesis advisor) / Wang, Robert (Committee member) / Tongay, Sefaattin (Committee member) / Arizona State University (Publisher)
Created2022
Description
It is well known that neighborhood contexts form an integral part in shaping development across the lifespan. At the same time, it is recognized that there is variability in the manner with which the neighborhood context is associated with pertinent outcomes, such as mental health and psychological well-being. In this regard, empirical research has differentiated between subjective and objective neighborhood indicators. Midlife is a critical life stage due to middle-aged adults being “sandwiched” between generations and being firmly entrenched in the workforce; in this regard, the neighborhood context could play a role in shaping mental health and psychological well-being in midlife. Of importance is determining which factors account for development in midlife, and whether individuals can find protective factors in order to preserve their health and psychological wellbeing into older adulthood. The purpose of this dissertation was to examine whether and how neighborhood context is associated with mental health and psychological well-being in midlife. The first study examined whether the subjective and objective neighborhood context moderates the impact of monthly adversity on mental health and psychological well-being in midlife. The second study aimed to examine whether and which potentially relevant latent factors exist among subjective and objective neighborhood indicators in a sample of middle-aged adults from the Phoenix Metropolitan area.
Taken together, the results of these studies provide evidence that neighborhood context is indeed relevant resource for middle-aged adults. Specifically, in Paper 1, found that individuals who live in neighborhoods with less disorder show fewer steep declines in mental health and well-being in months when an adversity was reported. Paper 2 found that that there are distinct latent constructs that were primarily comprised of factors related to resource and prosperity and financial strain for the objective indicators. For subjective perceptions factors comprised neighborhood insights. These findings contribute to the literature on potential ways in which neighborhood context may serve as a resource and serve as the groundwork for future studies that test mechanisms linking the neighborhood context to mental health and well-being in midlife and inform future intervention studies.
ContributorsStaben, Omar Enrique (Author) / Infurna, Frank J (Thesis advisor) / Sheehan, Connor (Committee member) / White, Rebecca (Committee member) / Grimm, Kevin (Committee member) / Arizona State University (Publisher)
Created2022
Description
humans are currently facing issues with the high level of carbon emissions that will cause global warming and climate change, which worsens the earth’s
environment. Buildings generate nearly 40% of annual global CO2 emissions, of which
28% is from building operations, and 11% from materials and construction. These
emissions must be decreased to protect from further environmental harm. The good news
is there is a way that carbon emissions can be decreased. The use of thermogalvanic
bricks enables electricity generation by the temperature difference between the enclosure
above the ceiling (i.e., the attic in a single-family home) and the living space below. A
ceiling tile prototype was constructed that can make use of this temperature difference to
generate electricity using an electrochemical system called a thermogalvanic cell.
Furthermore, the application of triply periodic minimal surfaces (TPMS) can increase the
thermal resistance of the ceiling tile, which is important for practical applications. Here,
Schwarz P TPMS structures were 3D-printed from polyvinylidene fluoride (PVDF), and
inserted into the electrolyte solution between the electrodes. Graphite was used as
electrodes on the positive and negative sides of the tile, and Iron (II) and Iron (III)
perchlorate salts were used as electrolytes. The maximum generated power was measured
with different porosities of TPMS structure, and one experiment without a TPMS
structure. The results indicated that as the porosity of the TPMS structure increases, the
maximum power decreases. The experiment with no TPMS structure had the largest
maximum power.
ContributorsWen, Chonghan (Author) / Phelan, Patrick (Thesis advisor) / Chen, Candace (Committee member) / Li, Xiangjia (Committee member) / Arizona State University (Publisher)
Created2022
Description
Dehumidifiers are ubiquitous and essential household appliances in many parts of the world. They are used extensively in tropical and sub-tropical environments to lower humidity in living spaces, where high ambient humidity can lead to numerous negative health effects from mild physical discomfort to more serious conditions such as mold build up in structures and dangerous illnesses in humans. Most common dehumidifiers are based on conventional mechanical refrigeration cycles, where the effects of condensation heat transfer play a critical role in their effectiveness. In these devices, humid ambient air flows over a cold evaporator, which lowers the temperature of the humid ambient air below its dew point temperature and therefore decreases its water content by causing liquid water condensation on the evaporator surface. The rate at which humidity can be extracted from the ambient air is governed in part by how quickly the evaporator can shed the condensed droplets. Recent advances in soft, stretchable, thermally enhanced (through the addition of liquid metals) silicone tubing offer the potential to use these stretchable tubes in place of conventional copper pipe for applications such as dehumidification. Copper is a common material choice for dehumidifier evaporator tubing owing to its ubiquity and its high thermal conductivity, but it has several thermal downsides. Specifically, copper tubes remain static and typically rely on gravity alone to remove water droplets when they reach a sufficient mass. Additionally, copper’s naturally hydrophilic surface promotes film-wise condensation, which is substantially less effective than dropwise condensation. In contrast to copper, thermally enhanced soft stretchable tubes have naturally hydrophobic surfaces that promote the more effective dropwise condensation mode and a soft surface that offers higher nucleation density. However, soft surfaces also increase droplet pinning, which inhibits their departure. This work experimentally explores the effects of periodic axial stretching and retraction of soft tubing internally cooled with water on droplet condensation dynamics on its exterior surface. Results are discussed in terms of overall system thermal performance and real-time condensation imaging. An overall null result is discovered, and recommendations for future experiments are made.
Contributorsnordstog, thomas (Author) / Rykaczewski, Konrad (Thesis advisor) / Wang, Robert (Committee member) / Devasenathipathy, Shankar (Committee member) / Arizona State University (Publisher)
Created2022