ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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Description
Traditional approaches to modeling microgrids include the behavior of each inverter operating in a particular network configuration and at a particular operating point. Such models quickly become computationally intensive for large systems. Similarly, traditional approaches to control do not use advanced methodologies and suffer from poor performance and limited operating range. In this document a linear model is derived for an inverter connected to the Thevenin equivalent of a microgrid. This model is then compared to a nonlinear simulation model and analyzed using the open and closed loop systems in both the time and frequency domains. The modeling error is quantified with emphasis on its use for controller design purposes. Control design examples are given using a Glover McFarlane controller, gain sched- uled Glover McFarlane controller, and bumpless transfer controller which are compared to the standard droop control approach. These examples serve as a guide to illustrate the use of multi-variable modeling techniques in the context of robust controller design and show that gain scheduled MIMO control techniques can extend the operating range of a microgrid. A hardware implementation is used to compare constant gain droop controllers with Glover McFarlane controllers and shows a clear advantage of the Glover McFarlane approach.
ContributorsSteenis, Joel (Author) / Ayyanar, Raja (Thesis advisor) / Mittelmann, Hans (Committee member) / Tsakalis, Konstantinos (Committee member) / Tylavsky, Daniel (Committee member) / Arizona State University (Publisher)
Created2013
Description
Arizona has become infamous for its strong nativist and anti-immigrant climate, gaining national and international attention for legislation and policing practices that are in violation of civil and human rights. Despite the grave injustices perpetuated against migrants and communities of color, they exist in an environment of acceptance. Applying Critical Pedagogy, Critical Race Theory/ Latina(o) Critical Race Theory, and Chicana Feminist epistemologies, this study interrogates the polarized discourse that has intensified in Arizona, within the immigration movement and across its political spectrum, from 2006 to 2008. I present an auto-ethnographic account, including use of participant action research, narrative, and storytelling methods that explores ways in which resistance is manifested and the implications for creating sustainable social change. I argue that legislation, raids, and local immigration enforcement tactics reinforce the dominant group's fear of the "other," resulting in micro and macro aggressions that legitimize racial profiling and help safeguard and fortify White privilege through the fabrication of racialized identities. Simultaneously, organizing strategies and discourse of immigrant rights advocates reflect an entanglement of perceived identities and a struggle to negotiate, contest, and redefine boundaries of public space. The raids, coupled with protests and counter demonstrations, produced a public spectacle that reinforces anti-immigrant connections between race and crime. Lastly, I apply and introduce Border Crit, a new and emerging theory I propose to better address research in the borderlands.
ContributorsMaldonado, Angeles (Author) / Swadener, Elizabeth B. (Thesis advisor) / Scott, Kimberly (Committee member) / Mckinley Jones Brayboy, Bryan (Committee member) / Arizona State University (Publisher)
Created2013
Description
Exiting prostitution is a process whereby women gradually leave prostitution after a number of environmental, relational, and cognitive changes have taken place. Most women attempting to leave street prostitution reenter five or more times before successfully exiting, if they are able to at all. Prostitution-exiting programs are designed to alleviate barriers to exiting, but several studies indicate only about 20-25% of participants enrolled in such programs are successful. There is little quantitative knowledge on the prostitution exiting process and current literature lacks a testable theory of exiting. This mixed-methods study defined and operationalized key cognitive processes by applying the Integrative Model of Behavioral Prediction (IMBP) to measure intentions to exit street-level prostitution. Intentions are thought to be a determinant of behavior and hypothesized as a function of attitudes, norms, and efficacy beliefs. The primary research objective was to measure and test a theory-driven hypothesis examining intentions to exit prostitution. To accomplish these aims, interviews were conducted with 16 men and women involved in prostitution to better capture the latent nuances of exiting (e.g., attitudinal changes, normative influence). These data informed the design of a quantitative instrument that was pilot-tested with a group of former prostitutes and reviewed by experts in the field. The quantitative phase focused on validating the instrument and testing the theory in a full latent variable structural equation model with a sample of 160 former and active prostitutes. Ultimately, the theory and instrument developed in this study will lay the foundation to test interventions for street prostituted women. Prior research has only been able to describe, but not explain or predict, the prostitution exiting process. This study fills a gap in literature by providing a quantitative examination of women's intentions to leave prostitution. The results contribute to our understanding of the cognitive changes that occur when a person leaves prostitution, and the validated instrument may be used as an intervention assessment or an exit prediction tool. Success in predicting an individual's passage through the exiting process could have important and far-reaching implications on recidivism policies or interventions for this vulnerable group of women.
ContributorsCimino, Andrea N (Author) / Gerdes, Karen E. (Thesis advisor) / Sun, Fei (Committee member) / Gillmore, Mary R (Committee member) / Arizona State University (Publisher)
Created2013
Description
Purpose: This study examines the role of social support on adjustment to widowhood. Past research has indicated that the role of social support on adjustment to widowhood remains inconclusive, and needs further examination. This study examines the varying coping trajectories of middle-aged and retired bereaved spouses. Additionally, this study examines how bereavement stage may also influence one's adaptation to widowhood. Methods: This study used in-depth and semi-structured interviews as a means of understanding the role of social support on adjustment to widowhood. Participants were recruited through two hospice services available in a major metropolitan area in the United States. Convenient and purposive samplings are used in this study; this study will execute a grounded theory approach in order to determine the inconclusive role of social support on adjustment to widowhood. This study is contrasting between two stages- life course stages (middle aged versus retirement aged people) and bereavement stages (a year or less time following the death of a spouse versus three or more years following the death of a spouse). As a means of reducing bias and subjectivity, all data collected during the interview will be transcribed immediately. Results: Middle-aged bereaved spouses reported higher levels of motivation for adjusting positively and quickly towards widowhood due to their concern for protecting the well-being of their surviving young children compared to retired bereaved spouses. Differences between middle-aged widows and widowers have been found in this study; middle-aged widowers have a higher linkage to negative health behaviors. Retired bereaved spouses may fare better depending upon their housing location. Living in a retirement center may lower negative effects of bereavement on retired spouses' health. Conclusions: Types of social support received and expected varied between middle-aged widows and widowers. Gender norms may influence the type of social support widows and widowers receive. Middle-aged widowers are less likely to receive emotional support which may explain their higher linkage to negative health behaviors. Bereavement stage and housing location may be the key factors that influence widowhood trajectories of retired bereaved spouses. Living in a retirement center may lower the negative effects of bereavement on overall health.
ContributorsRafieei, Noshin (Author) / Kronenfeld, Jennie (Thesis advisor) / Haas, Steven (Committee member) / Damgaard, Anni (Committee member) / Arizona State University (Publisher)
Created2013
Description
The object of this study was a 26 year old residential Photovoltaic (PV) monocrystalline silicon (c-Si) power plant, called Solar One, built by developer John F. Long in Phoenix, Arizona (a hot-dry field condition). The task for Arizona State University Photovoltaic Reliability Laboratory (ASU-PRL) graduate students was to evaluate the power plant through visual inspection, electrical performance, and infrared thermography. The purpose of this evaluation was to measure and understand the extent of degradation to the system along with the identification of the failure modes in this hot-dry climatic condition. This 4000 module bipolar system was originally installed with a 200 kW DC output of PV array (17 degree fixed tilt) and an AC output of 175 kVA. The system was shown to degrade approximately at a rate of 2.3% per year with no apparent potential induced degradation (PID) effect. The power plant is made of two arrays, the north array and the south array. Due to a limited time frame to execute this large project, this work was performed by two masters students (Jonathan Belmont and Kolapo Olakonu) and the test results are presented in two masters theses. This thesis presents the results obtained on the north array and the other thesis presents the results obtained on the south array. The resulting study showed that PV module design, array configuration, vandalism, installation methods and Arizona environmental conditions have had an effect on this system's longevity and reliability. Ultimately, encapsulation browning, higher series resistance (potentially due to solder bond fatigue) and non-cell interconnect ribbon breakages outside the modules were determined to be the primary causes for the power loss.
ContributorsBelmont, Jonathan (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Henderson, Mark (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2013
Description
Criminologists have directed significant theoretical and empirical attention toward the institution of marriage over the past two decades. Importantly, the momentum guiding this line of research has increased despite the fact that people are getting married far less often and much later in the life course than in any point in American history. The aim of this dissertation is to address this disconnect by focusing attention to nonmarital romantic relationships and their instability during emerging adulthood. To do so, it uses data from the Pathways to Desistance Study, a longitudinal study of 1,354 at-risk males and females who were adjudicated from the juvenile and adult systems in Phoenix and Philadelphia between 2000 and 2003. The project focuses attention to the following issues: (1) the effect of romantic dissolution on aggressive and income-based offenses; (2) the extent to which strain
egative emotionality and peer influence/exposure account for the effect of romantic dissolution on crime; and (3) the extent to which certain relationship and individual circumstances moderate the effect of romantic dissolution. The models reveal a few key findings. First, romantic dissolution is strongly related to an increase in both aggressive and income-based crime, but is more strongly related to income-based crime. Second, the effect of romantic dissolution is reduced when measures of strain
egative emotionality and peer influence/exposure measures are added to models, but the peer influence/exposure measures account for the strongest reduction. Finally, romantic dissolution does not serve as a positive life event among these at-risk youth, but its effect is exacerbated under a number of contexts (e.g. when an individual is unemployed). This study closes with a summary of these findings as well as its key limitations, and offers insight into potential policy implications and avenues of future research.
egative emotionality and peer influence/exposure account for the effect of romantic dissolution on crime; and (3) the extent to which certain relationship and individual circumstances moderate the effect of romantic dissolution. The models reveal a few key findings. First, romantic dissolution is strongly related to an increase in both aggressive and income-based crime, but is more strongly related to income-based crime. Second, the effect of romantic dissolution is reduced when measures of strain
egative emotionality and peer influence/exposure measures are added to models, but the peer influence/exposure measures account for the strongest reduction. Finally, romantic dissolution does not serve as a positive life event among these at-risk youth, but its effect is exacerbated under a number of contexts (e.g. when an individual is unemployed). This study closes with a summary of these findings as well as its key limitations, and offers insight into potential policy implications and avenues of future research.
ContributorsLarson, Matthew Joseph (Author) / Sweeten, Gary (Thesis advisor) / Piquero, Alex (Committee member) / Spohn, Cassia (Committee member) / Wallace, Danielle (Committee member) / Arizona State University (Publisher)
Created2013
Description
This thesis builds upon previous research exploring the different factors that influence divorce access attitudes, using data drawn from the General Social Survey in 1991, 1994, and 2008. I examine different social values and economic characteristics and their influence on divorce access attitudes, and explore gender differences within these factors. I examine how information drawn from this analysis supports the argument for Second Demographic Transition Theory as a theoretical framework to explain influential factors in the formation of divorce access attitudes. I conclude that social values variables related to attitudes towards sex behaviors remain significant predictors of divorce access attitudes. I also recognize that socioeconomic context bears influence on the formation of divorce access attitudes. Gender differences lead to the conclusion that behavior and interactions around divorce access attitude formation are dynamic and complex, but are effectively explained using Second Demographic Transition Theory.
ContributorsFrump, Jonathan (Author) / Hayford, Sarah (Thesis advisor) / Glick, Jennifer (Committee member) / Yabiku, Scott (Committee member) / Arizona State University (Publisher)
Created2013
Description
Dye sensitized solar cells (DSSCs) are currently being explored as a cheaper alternative to the more common silicon (Si) solar cell technology. In addition to the cost advantages, DSSCs show good performance in low light conditions and are not sensitive to varying angles of incident light like traditional Si cells. One of the major challenges facing DSSCs is loss of the liquid electrolyte, through evaporation or leakage, which lowers stability and leads to increased degradation. Current research with solid-state and quasi-solid DSSCs has shown success regarding a reduction of electrolyte loss, but at a cost of lower conversion efficiency output. The research work presented in this paper focuses on the effects of using nanoclay material as a gelator in the electrolyte of the DSSC. The data showed that the quasi-solid cells are more stable than their liquid electrolyte counterparts, and achieved equal or better I-V characteristics. The quasi-solid cells were fabricated with a gel electrolyte that was prepared by adding 7 wt% of Nanoclay, Nanomer® (1.31PS, montmorillonite clay surface modified with 15-35% octadecylamine and 0.5-5 wt% aminopropyltriethoxysilane, Aldrich) to the iodide/triiodide liquid electrolyte, (Iodolyte AN-50, Solaronix). Various gel concentrations were tested in order to find the optimal ratio of nanoclay to liquid. The gel electrolyte made with 7 wt% nanoclay was more viscous, but still thin enough to allow injection with a standard syringe. Batches of cells were fabricated with both liquid and gel electrolyte and were evaluated at STC conditions (25°C, 100 mW/cm2) over time. The gel cells achieved efficiencies as high as 9.18% compared to 9.65% achieved by the liquid cells. After 10 days, the liquid cell decreased to 1.75%, less than 20% of its maximum efficiency. By contrast, the gel cell's efficiency increased for two weeks, and did not decrease to 20% of maximum efficiency until 45 days. After several measurements, the liquid cells showed visible signs of leakage through the sealant, whereas the gel cells did not. This resistance to leakage likely contributed to the improved performance of the quasi-solid cells over time, and is a significant advantage over liquid electrolyte DSSCs.
ContributorsMain, Laura (Author) / Munukutla, Lakshmi (Thesis advisor) / Madakannan, Arunachalanadar (Committee member) / Polesky, Gerald (Committee member) / Arizona State University (Publisher)
Created2012
Description
Potential induced degradation (PID) due to high system voltages is one of the major degradation mechanisms in photovoltaic (PV) modules, adversely affecting their performance due to the combined effects of the following factors: system voltage, superstrate/glass surface conductivity, encapsulant conductivity, silicon nitride anti-reflection coating property and interface property (glass/encapsulant; encapsulant/cell; encapsulant/backsheet). Previous studies carried out at ASU's Photovoltaic Reliability Laboratory (ASU-PRL) showed that only negative voltage bias (positive grounded systems) adversely affects the performance of commonly available crystalline silicon modules. In previous studies, the surface conductivity of the glass surface was obtained using either conductive carbon layer extending from the glass surface to the frame or humidity inside an environmental chamber. This thesis investigates the influence of glass surface conductivity disruption on PV modules. In this study, conductive carbon was applied only on the module's glass surface without extending to the frame and the surface conductivity was disrupted (no carbon layer) at 2cm distance from the periphery of frame inner edges. This study was carried out under dry heat at two different temperatures (60 °C and 85 °C) and three different negative bias voltages (-300V, -400V, and -600V). To replicate closeness to the field conditions, half of the selected modules were pre-stressed under damp heat for 1000 hours (DH 1000) and the remaining half under 200 hours of thermal cycling (TC 200). When the surface continuity was disrupted by maintaining a 2 cm gap from the frame to the edge of the conductive layer, as demonstrated in this study, the degradation was found to be absent or negligibly small even after 35 hours of negative bias at elevated temperatures. This preliminary study appears to indicate that the modules could become immune to PID losses if the continuity of the glass surface conductivity is disrupted at the inside boundary of the frame. The surface conductivity of the glass, due to water layer formation in a humid condition, close to the frame could be disrupted just by applying a water repelling (hydrophobic) but high transmittance surface coating (such as Teflon) or modifying the frame/glass edges with water repellent properties.
ContributorsTatapudi, Sai Ravi Vasista (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Srinivasan, Devarajan (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2012
Description
ABSTRACT As the use of photovoltaic (PV) modules in large power plants continues to increase globally, more studies on degradation, reliability, failure modes, and mechanisms of field aged modules are needed to predict module life expectancy based on accelerated lifetime testing of PV modules. In this work, a 26+ year old PV power plant in Phoenix, Arizona has been evaluated for performance, reliability, and durability. The PV power plant, called Solar One, is owned and operated by John F. Long's homeowners association. It is a 200 kWdc, standard test conditions (STC) rated power plant comprised of 4000 PV modules or frameless laminates, in 100 panel groups (rated at 175 kWac). The power plant is made of two center-tapped bipolar arrays, the north array and the south array. Due to a limited time frame to execute this large project, this work was performed by two masters students (Jonathan Belmont and Kolapo Olakonu) and the test results are presented in two masters theses. This thesis presents the results obtained on the south array and the other thesis presents the results obtained on the north array. Each of these two arrays is made of four sub arrays, the east sub arrays (positive and negative polarities) and the west sub arrays (positive and negative polarities), making up eight sub arrays. The evaluation and analyses of the power plant included in this thesis consists of: visual inspection, electrical performance measurements, and infrared thermography. A possible presence of potential induced degradation (PID) due to potential difference between ground and strings was also investigated. Some installation practices were also studied and found to contribute to the power loss observed in this investigation. The power output measured in 2011 for all eight sub arrays at STC is approximately 76 kWdc and represents a power loss of 62% (from 200 kW to 76 kW) over 26+ years. The 2011 measured power output for the four south sub arrays at STC is 39 kWdc and represents a power loss of 61% (from 100 kW to 39 kW) over 26+ years. Encapsulation browning and non-cell interconnect ribbon breakages were determined to be the primary causes for the power loss.
ContributorsOlakonu, Kolapo (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Srinivasan, Devarajan (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2012