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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- All Subjects: Climate Change
- All Subjects: Educational Administration
Description
Farmer-Managed Irrigation Systems (FMIS) are community managed and operated irrigation systems, celebrated for their successful governance of water resources for many decades and in several countries. Nevertheless, in the face of climatic, political, and social change, their future is uncertain. This dissertation utilizes household adaptive capacity, socio-ecological system (SES) robustness, and the Institutional Analysis and Development framework to structure a multi-scalar and multi-stressor analysis of changes experienced in Nepal’s FMIS. The dissertation documents irrigators’ perception of environmental change, impacts, and response; diagnoses the multiple disturbances impacting the robustness of the FMIS; and analyzes changes in the FMIS as an institution over time, in an effort to understand the major drivers of SES change. Fifteen FMIS from five districts of Nepal were selected for the study. Data were collected through field observations, household surveys, key informant interviews, and focus group discussions. The status of the existing rules was compared with the data collected three decades ago in the Nepal Irrigation Institutions and Systems database. This study finds that FMIS’s robustness is threatened by uncertain water supply, inefficient infrastructure, scarcity of farm labor, weakening collective action, and natural disasters. Farm households, whose actions are necessary to sustain the management of FMIS, perceive environmental change differently according to their ecological region and position along the irrigation canal, leading to different adaptation strategies. Despite livelihood diversification, irrigators rely primarily on irrigation infrastructure management to respond to the impacts of environmental change. Institutional analysis demonstrates the evolution of FMIS in terms of working rules in the face of multiple stressors. In this study, payoff, information, and position rules have exhibited the most substantive change. However, boundary, choice, aggregation, and scope rules are less likely to change. The findings of this work point to the need for geographically differentiated adaptation support policies, and a need for closer attention to the dynamics of labor, environmental change, and institutional persistence in agriculture and irrigation sectors. FMIS being an exemplary institutional arrangement for the study of a SES, the research findings benefit similar institutions globally facing challenges to the sustainable governance of common pool resources.
ContributorsParajuli, Jagadish (Author) / Eakin, Hallie (Thesis advisor) / Chhetri, Netra (Thesis advisor) / Anderies, Marty (Committee member) / Arizona State University (Publisher)
Created2021
Description
Crystalline silicon covers more than 85% of the global photovoltaics industry and has sustained a nearly 30% year-over-year growth rate. Continued cost and capital expenditure (CAPEX) reductions are needed to sustain this growth. Using thin silicon wafers well below the current industry standard of 160 µm can reduce manufacturing cost, CAPEX, and levelized cost of electricity. Additionally, thinner wafers enable more flexible and lighter module designs, making them more compelling in market segments like building-integrated photovoltaics, portable power, aerospace, and automotive industries. Advanced architectures and superior surface passivation schemes are needed to enable the use of very thin silicon wafers. Silicon heterojunction (SHJ) and SHJ with interdigitated back contact solar cells have demonstrated open-circuit voltages surpassing 720 mV and the potential to surpass 25% conversion efficiency. These factors have led to an increasing interest in exploring SHJ solar cells on thin wafers. In this work, the passivation capability of the thin intrinsic hydrogenated amorphous silicon layer is improved by controlling the deposition temperature and the silane-to-hydrogen dilution ratio. An effective way to parametrize surface recombination is by using surface saturation current density and a very low surface saturation density is achieved on textured wafers for wafer thicknesses ranging between 40 and 180 µm which is an order of magnitude lesser compared to the prevalent industry standards. Implied open-circuit voltages over 760 mV were accomplished on SHJ structures deposited on n-type silicon wafers with thicknesses below 50 µm. An analytical model is also described for a better understanding of the variation of the recombination fractions for varying substrate thicknesses. The potential of using very thin wafers is also established by manufacturing SHJ solar cells, using industrially pertinent processing steps, on 40 µm thin standalone wafers while achieving maximum efficiency of 20.7%. It is also demonstrated that 40 µm thin SHJ solar cells can be manufactured using these processes on large areas. An analysis of the percentage contribution of current, voltage, and resistive losses are also characterized for the SHJ devices fabricated in this work for varying substrate thicknesses.
ContributorsBalaji, Pradeep (Author) / Bowden, Stuart (Thesis advisor) / Alford, Terry (Thesis advisor) / Goryll, Michael (Committee member) / Augusto, Andre (Committee member) / Arizona State University (Publisher)
Created2021
Assessing the Response of Macroinvertebrate Communities to River Flow Dynamics in the Sonoran Desert
Description
Climate change is causing hydrologic intensification globally by increasing both the frequency and magnitude of floods and droughts. While environmental variation is a key regulator at all levels of ecological organization, such changes to the hydrological cycle that are beyond the normal range of variability can have strong impacts on stream and riparian ecosystems within sensitive landscapes, such as the American Southwest. The main objective of this study was to investigate how anomalous hydrologic variability influences macroinvertebrate communities in desert streams. I studied seasonal changes in aquatic macroinvertebrate abundances in eleven streams that encompass a hydrologic gradient across Arizona’s Sonoran Desert. This analysis was coupled with the quantification and assessment of stochastic hydrology to determine influences of flow regimes and discrete events on invertebrate community composition. I found high community variability within sites, illustrated by seasonal measures of beta diversity and nonmetric multidimensional scaling (NMDS) plots. I observed notable patterns of NMDS data points when invertebrate abundances were summarized by summer versus winter surveys. These results suggest that there is a difference within the communities between summer and winter seasons, irrespective of differences in site hydroclimate. Estimates of beta diversity were the best metric for summarizing and comparing diversity among sites, compared to richness difference and replacement. Seasonal measures of beta diversity either increased, decreased, or stayed constant across the study period, further demonstrating the high variation within and among study sites. Regime shifts, summarized by regime shift frequency (RSF) and mean net annual anomaly (NAA), and anomalous events, summarized by the power of blue noise (Maximum Blue Noise), were the best predictors of macroinvertebrate diversity, and thus should be more widely applied to ecological data. These results suggest that future studies of community composition in freshwater systems should focus on understanding the cause of variation in biodiversity gradients. This study highlights the importance of considering both flow regimes and discrete anomalous events when studying spatial and temporal variation in stream communities.
ContributorsSainz, Ruby (Author) / Sabo, John L (Thesis advisor) / Grimm, Nancy (Committee member) / Stampoulis, Dimitrios (Committee member) / Arizona State University (Publisher)
Created2021
Description
The purpose of this action research study was to better understand how aspiring school leaders orient themselves toward present and future uncertainty and to explore what mindsets and conceptual understandings they believe they need to lead through uncertainty. An innovation, delivered through a graduate course on leading change in a Master of Educational Leadership program, focused on supporting participants’ mindsets and conceptual understanding toward leading change in the midst of uncertainty, including the COVID-19 global pandemic. A total of 34 students participated in this qualitative case study. The educational innovation was designed by this action researcher and was informed by transformative leadership theory, design thinking, and imagination. Four sources of data were used to answer the research questions, including students’ written assignments and video reflection assignments, as well as researcher course observations and semi-structured interviews with participants. Major findings suggested that the educational innovation was effective in supporting participants identity development as transformative leaders, as well as supporting participants’ adoption of design thinking mindsets and use of imagination as tools for leading change in complex systems and during uncertain times.
ContributorsScragg, Benjamin S (Author) / Giorgis, Cyndi (Thesis advisor) / Hermanns, Carl (Committee member) / Loescher, Shawn T (Committee member) / Arizona State University (Publisher)
Created2021
Description
Academic integrity among college students continues to be a problem at colleges and universities. This is particularly important for journalism students where ethical issues in the profession are critical, especially in an era of “fake news” and distrust in the media. While most journalism students study professional ethics, they do not necessarily make the connection between their future careers and their academic career. In fact, at Western Washington University (Western) a recent exploration into academic dishonesty revealed that violations were increasing, and that journalism was one of the top three majors where violations occurred (based on percent of majors). To address this problem of practice, an online academic integrity resource – specific to journalism – was developed to see whether it could increase students’ knowledge as it relates to academic integrity and decrease violations. The mixed methods action research (MMAR) study took place during summer and fall quarter at Western Washington University, a state university located in Bellingham, Washington. Participants included students who were pre-majors, majors, and minors in the three tracks of journalism: news-editorial, public relations, and visual journalism. They were given multiple opportunities to self-enroll in the Resource for Ethical Academic Development (READ) Canvas course for academic integrity. Self-efficacy theory and social learning theory provided a framework for the study. Data was collected through pre- and post-innovation surveys as well as qualitative interviews. Quantitative results suggest that there is work yet to do in order to educate students about academic integrity and potential consequences of behavior. Qualitative results suggest that one avenue may be through an online resource that provides concise and comprehensive information, models behavior relevant to the student’s own discipline, and is easily accessible. It also suggests that a culture change from a systemic emphasis on grades to a focus on growth and individual learning may be beneficial.
ContributorsKeller, Jennifer Margaret (Author) / Henriksen, Danah (Thesis advisor) / Silcock, Bill (Committee member) / VanderStaay, Steven (Committee member) / Arizona State University (Publisher)
Created2021
Description
Academic advisors play a critical role in student success within United States institutions of higher education. Although uniquely positioned to contribute to important institutional and student outcomes, academic advising is identified in the literature as an emerging profession, often delegitimizing advisor authority and limiting their contribution to institutional objectives. A review of the literature explores the history academic advising, and the current state of professionalization of the field. Additionally, entrepreneurial mindset is introduced as a framework of practice for professional agency. As a field working to professionalize itself within the higher education context, academic advisors must be able to fully participate and contribute to the process of developing innovative practices within the contexts of their institutions. This mixed-methods study drew upon proactive work behavior as defined by Hackman and Oldham to understand how academic advisors demonstrate and perceive their professional agency and ability to make decisions when working with students in the context of their role. Findings suggest professional agency as a construct exists not as a stand-alone concept, but rather as part of an ecosystem within the institution that includes layered systems, structures, and cultures which influence advisor behaviors and how they navigate decision-making. Implications include considerations for academic advising leaders and administrators, specifically related to departmental structures and advisor perceptions of their professional agency. This study contributes to the advising literature in the area of professionalization, with implications for scholarship and practice that can address gaps in the current scholarship.
ContributorsRudd, Melissa (Author) / Basile, Carole (Thesis advisor) / Kim, Jeongeun (Committee member) / Mcintyre, Lisa (Committee member) / Arizona State University (Publisher)
Created2021
Description
Energy consumption in buildings, accounting for 41% of 2010 primary energy consumption in the United States (US), is particularly vulnerable to climate change due to the direct relationship between space heating/cooling and temperature. Past studies have assessed the impact of climate change on long-term mean and/or peak energy demands. However, these studies usually neglected spatial variations in the “balance point” temperature, population distribution effects, air-conditioner (AC) saturation, and the extremes at smaller spatiotemporal scales, making the implications of local-scale vulnerability incomplete. Here I develop empirical relationships between building energy consumption and temperature to explore the impact of climate change on long-term mean and extremes of energy demand, and test the sensitivity of these impacts to various factors. I find increases in summertime electricity demand exceeding 50% and decreases in wintertime non-electric energy demand of more than 40% in some states by the end of the century. The occurrence of the most extreme (appearing once-per-56-years) electricity demand increases more than 2600 fold, while the occurrence of the once per year extreme events increases more than 70 fold by the end of this century. If the changes in population and AC saturation are also accounted for, the impact of climate change on building energy demand will be exacerbated.
Using the individual building energy simulation approach, I also estimate the impact of climate change to different building types at over 900 US locations. Large increases in building energy consumption are found in the summer, especially during the daytime (e.g., >100% increase for warehouses, 5-6 pm). Large variation of impact is also found within climate zones, suggesting a potential bias when estimating climate-zone scale changes with a small number of representative locations.
As a result of climate change, the building energy expenditures increase in some states (as much as $3 billion/year) while in others, costs decline (as much as $1.4 billion/year). Integrated across the contiguous US, these variations result in a net savings of roughly $4.7 billion/year. However, this must be weighed against the cost (exceeding $19 billion) of adding electricity generation capacity in order to maintain the electricity grid’s reliability in summer.
Using the individual building energy simulation approach, I also estimate the impact of climate change to different building types at over 900 US locations. Large increases in building energy consumption are found in the summer, especially during the daytime (e.g., >100% increase for warehouses, 5-6 pm). Large variation of impact is also found within climate zones, suggesting a potential bias when estimating climate-zone scale changes with a small number of representative locations.
As a result of climate change, the building energy expenditures increase in some states (as much as $3 billion/year) while in others, costs decline (as much as $1.4 billion/year). Integrated across the contiguous US, these variations result in a net savings of roughly $4.7 billion/year. However, this must be weighed against the cost (exceeding $19 billion) of adding electricity generation capacity in order to maintain the electricity grid’s reliability in summer.
ContributorsHuang, Jianhua (Author) / Gurney, Kevin Robert (Thesis advisor) / Miller, Clark Anson (Committee member) / Rey, Sergio J (Committee member) / Georgescu, Matei (Committee member) / Arizona State University (Publisher)
Created2016
Description
In an effort to better prepare K-12 students for college and career readiness, Advancement Via Individual Determination (AVID) has created a college and career readiness system that is implemented in schools across the United States and in many international locations. Part of this system of schoolwide transformation, is the AVID Elective class, designed for students in the academic-middle. In the AVID Elective, students are supported in their efforts to attend four-year universities. A critical aspect of the AVID Elective class is the weekly implementation of AVID Tutorials, ideally led by trained college tutor/mentors.
The purpose of this action research study is to investigate support structures of AVID Tutors beyond the current tutor training system, in order to see how additional methods can contribute to continual improvement of the tutor training system. Findings from this study indicate that expanding current tutor-training practice to include a blended-learning, on-the-job model, might be beneficial for AVID Tutors and AVID Students.
Through a mixed methods action research study, both qualitative and quantitative data collection tools were employed to help understand the effect of additional tutor training supports. Interviews, tutor assignments, observations of tutorials, and pre- and post-tests provide the bulk of the data studied. Further, this study could provide critical information for key AVID stakeholders who seek to offer training to tutors in AVID.
The purpose of this action research study is to investigate support structures of AVID Tutors beyond the current tutor training system, in order to see how additional methods can contribute to continual improvement of the tutor training system. Findings from this study indicate that expanding current tutor-training practice to include a blended-learning, on-the-job model, might be beneficial for AVID Tutors and AVID Students.
Through a mixed methods action research study, both qualitative and quantitative data collection tools were employed to help understand the effect of additional tutor training supports. Interviews, tutor assignments, observations of tutorials, and pre- and post-tests provide the bulk of the data studied. Further, this study could provide critical information for key AVID stakeholders who seek to offer training to tutors in AVID.
ContributorsGarcia, Michael B (Author) / Kulinna-Hodges, Pamela (Thesis advisor) / Carlson, David (Committee member) / Johnston, Dennis (Committee member) / Arizona State University (Publisher)
Created2018
Description
Nonlinear responses in the dynamics of climate system could be triggered by small change of forcing. Interactions between different components of Earth’s climate system are believed to cause abrupt and catastrophic transitions, of which anthropogenic forcing is a major and the most irreversible driver. Meantime, in the face of global climate change, extreme climatic events, such as extreme precipitations, heatwaves, droughts, etc., are projected to be more frequent, more intense, and longer in duration. These nonlinear responses in climate dynamics from tipping points to extreme events pose serious threats to human society on a large scale. Understanding the physical mechanisms behind them has potential to reduce related risks through different ways. The overarching objective of this dissertation is to quantify complex interactions, detect tipping points, and explore propagations of extreme events in the hydroclimate system from a new structure-based perspective, by integrating climate dynamics, causal inference, network theory, spectral analysis, and machine learning. More specifically, a network-based framework is developed to find responses of hydroclimate system to potential critical transitions in climate. Results show that system-based early warning signals towards tipping points can be located successfully, demonstrated by enhanced connections in the network topology. To further evaluate the long-term nonlinear interactions among the U.S. climate regions, causality inference is introduced and directed complex networks are constructed from climatology records over one century. Causality networks reveal that the Ohio valley region acts as a regional gateway and mediator to the moisture transport and thermal transfer in the U.S. Furthermore, it is found that cross-regional causality variability manifests intrinsic frequency ranging from interannual to interdecadal scales, and those frequencies are associated with the physics of climate oscillations. Besides the long-term climatology, this dissertation also aims to explore extreme events from the system-dynamic perspective, especially the contributions of human-induced activities to propagation of extreme heatwaves in the U.S. cities. Results suggest that there are long-range teleconnections among the U.S. cities and supernodes in heatwave spreading. Findings also confirm that anthropogenic activities contribute to extreme heatwaves by the fact that causality during heatwaves is positively associated with population in megacities.
ContributorsYang, Xueli (Author) / Yang, Zhihua (Thesis advisor) / Lai, Ying-Cheng (Committee member) / Li, Qi (Committee member) / Xu, Tianfang (Committee member) / Zeng, Ruijie (Committee member) / Arizona State University (Publisher)
Created2023
Description
Academic tracking has long been a subject of debate due to its potential impact on educational equity, with students who are tracked highly receiving a higher quality
education in comparison to students tracked lowly. These disparities in education quality
may be affecting students’ outcomes, as it has been demonstrated that the short-term
academic outcomes of students, such as their grades, tend to be affected by their
academic track positioning. This dissertation builds upon these previous findings by
utilizing a subsample of 20,584 students from the High School Longitudinal Study (2009)
to examine the relation between academic track positioning and post-secondary education
attendance, program length, college major, and expected future job. Additionally, the
relation between academic tracking and each of these outcomes was also assessed using
mediation, with potential mediators including education aspiration, expectations, and
academic self-efficacy. Findings suggest that academic track positioning in math and
science are influential in students’ post-secondary and career outcomes, with students
who are positioned highly in either subject having greater post-secondary attendance,
program length, higher representation in STEM college majors, and expectations for
future jobs in STEM fields in comparison to students tracked lowly. Additionally,
education aspirations and expectations mediated the relations between math academic
track positioning and each of the outcomes, although the effects were small in size.
Educators should consider exploring avenues for improving education quality in low
academic tracks.
ContributorsWoods, Kenton Bentley (Author) / Hanish, Laura (Thesis advisor) / DeLay, Dawn (Committee member) / Martin, Carol (Committee member) / Jager, Justin (Committee member) / Arizona State University (Publisher)
Created2023