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
This qualitative, action research study examines how teacher-writers' identities are constructed through the practice of revision in an extra-curriculum writing group. The writing group was designed to support the teacher-writers as they revised classroom research projects for submission for a scholarly journal. Using discourse analysis, the researcher explores how the teacher-writers' identities are constructed in the contested spaces of revision. This exploration focuses on contested issues that invariably emerge in a dynamic binary of reader/writer, issues of authority, ownership, and unstable reader and writer identities. By negotiating these contested spaces--these contact zones--the teacher-writers construct opportunities to flex their rhetorical agency. Through rhetorical agency, the teacher-writers shift their discoursal identities by discarding and acquiring a variety of discourses. As a result, the practice of revision constructs the teacher-writers identities as hybrid, as consisting of self and other.
ContributorsClark-Oates, Angela (Author) / Smith, Karen (Thesis advisor) / Roen, Duane (Thesis advisor) / Fischman, Gustavo (Committee member) / Early, Jessica (Committee member) / Arizona State University (Publisher)
Created2013
Description
A simple passion for reading compels many to enter the university literature classroom. What happens once they arrive may fuel that passion, or possibly destroy it. A romanticized relationship with literature proves to be an obstacle that hinders a deeper and richer engagement with texts. Primary research consisting of personal interviews, observations, and surveys, form the source of data for this dissertation project which was designed to examine how literature teachers engage their students with texts, discussion, and assignments in the university setting. Traditionally text centered and resolute, literature courses will need refashioning if they are to advance beyond erstwhile conventions. The goal of this study is to create space for a dialogue about the need for a pedagogy of literature.
ContributorsSanchez, Shillana (Author) / Goggin, Maureen (Thesis advisor) / Tobin, Beth (Thesis advisor) / Rose, Shirley (Committee member) / Arizona State University (Publisher)
Created2013
Description
For CFD validation, hypersonic flow fields are simulated and compared with experimental data specifically designed to recreate conditions found by hypersonic vehicles. Simulated flow fields on a cone-ogive with flare at Mach 7.2 are compared with experimental data from NASA Ames Research Center 3.5" hypersonic wind tunnel. A parametric study of turbulence models is presented and concludes that the k-kl-omega transition and SST transition turbulence model have the best correlation. Downstream of the flare's shockwave, good correlation is found for all boundary layer profiles, with some slight discrepancies of the static temperature near the surface. Simulated flow fields on a blunt cone with flare above Mach 10 are compared with experimental data from CUBRC LENS hypervelocity shock tunnel. Lack of vibrational non-equilibrium calculations causes discrepancies in heat flux near the leading edge. Temperature profiles, where non-equilibrium effects are dominant, are compared with the dissociation of molecules to show the effects of dissociation on static temperature. Following the validation studies is a parametric analysis of a hypersonic inlet from Mach 6 to 20. Compressor performance is investigated for numerous cowl leading edge locations up to speeds of Mach 10. The variable cowl study showed positive trends in compressor performance parameters for a range of Mach numbers that arise from maximizing the intake of compressed flow. An interesting phenomenon due to the change in shock wave formation for different Mach numbers developed inside the cowl that had a negative influence on the total pressure recovery. Investigation of the hypersonic inlet at different altitudes is performed to study the effects of Reynolds number, and consequently, turbulent viscous effects on compressor performance. Turbulent boundary layer separation was noted as the cause for a change in compressor performance parameters due to a change in Reynolds number. This effect would not be noticeable if laminar flow was assumed. Mach numbers up to 20 are investigated to study the effects of vibrational and chemical non-equilibrium on compressor performance. A direct impact on the trends on the kinetic energy efficiency and compressor efficiency was found due to dissociation.
ContributorsOliden, Daniel (Author) / Lee, Tae-Woo (Thesis advisor) / Peet, Yulia (Committee member) / Huang, Huei-Ping (Committee member) / Arizona State University (Publisher)
Created2013
Description
Derived from the necessity to increase testing capabilities of hybrid rocket motor (HRM) propulsion systems for Daedalus Astronautics at Arizona State University, a small-scale motor and test stand were designed and developed to characterize all components of the system. The motor is designed for simple integration and setup, such that both the forward-end enclosure and end cap can be easily removed for rapid integration of components during testing. Each of the components of the motor is removable allowing for a broad range of testing capabilities. While examining injectors and their potential it is thought ideal to obtain the highest regression rates and overall motor performance possible. The oxidizer and fuel are N2O and hydroxyl-terminated polybutadiene (HTPB), respectively, due to previous experience and simplicity. The injector designs, selected for the same reasons, are designed such that they vary only in the swirl angle. This system provides the platform for characterizing the effects of varying said swirl angle on HRM performance.
ContributorsSummers, Matt H (Author) / Lee, Taewoo (Thesis advisor) / Chen, Kangping (Committee member) / Wells, Valana (Committee member) / Arizona State University (Publisher)
Created2013
Description
A new theoretical model was developed utilizing energy conservation methods in order to determine the fully-atomized cross-sectional Sauter mean diameters of pressure-swirl atomizers. A detailed boundary-layer assessment led to the development of a new viscous dissipation model for droplets in the spray. Integral momentum methods were also used to determine the complete velocity history of the droplets and entrained gas in the spray. The model was extensively validated through comparison with experiment and it was found that the model could predict the correct droplet size with high accuracy for a wide range of operating conditions. Based on detailed analysis, it was found that the energy model has a tendency to overestimate the droplet diameters for very low injection velocities, Weber numbers, and cone angles. A full parametric study was also performed in order to unveil some underlying behavior of pressure-swirl atomizers. It was found that at high injection velocities, the kinetic energy in the spray is significantly larger than the surface tension energy, therefore, efforts into improving atomization quality by changing the liquid's surface tension may not be the most productive. From the parametric studies it was also shown how the Sauter mean diameter and entrained velocities vary with increasing ambient gas density. Overall, the present energy model has the potential to provide quick and reasonably accurate solutions for a wide range of operating conditions enabling the user to determine how different injection parameters affect the spray quality.
ContributorsMoradi, Ali (Author) / Lee, Taewoo (Thesis advisor) / Herrmann, Marcus (Committee member) / Huang, Huei-Ping (Committee member) / Arizona State University (Publisher)
Created2013
Description
This study compares some sites, structures, theories and praxis of transnational feminisms in India and the U.S., simultaneously guided by and interrogating contemporary academic feminist theoretical and methodological trends. The goal is twofold: to understand similarities and differences in feminist praxis of two geo-epistemological spaces; and to interrogate the notion and currency of the "transnational" within feminist knowledge-creation. The phenomenon of transnational feminist knowledge-making is interrogated from a philosophical/theoretical and phenomenological/experiential standpoint. The philosophical inquiry is concentrated on the theoretical texts produced on transnational/global/postcolonial feminisms. This inquiry also focuses on some unpublished, uncirculated archival materials that trace the history of academic feminisms and their transnationalization. The phenomenological side focuses on interview and survey data on transnational feminism, gathered from feminist practitioners working in the U.S. and India, as well as being "transmigrant," or "traveling scholars." Digital/institutional ethnography is used to ground the findings in operational spaces of knowledge-making, including cyberspace. This research shows that the global logic of circulation and visibility organize the flow of knowledge as data, narratives and reports from the global south, which are analyzed, clarified and theorized in the global north. Perhaps responding to many critiques on "speaking of" and "speaking for" the "other," the trend to represent third world women as perpetual victims has given way to newer representations and accounts of resistance, collaboration, and activism. However, this creates a fresh "theory-here-activism-there" model of transnational feminism that preserves unequal feminist division of labor. This comparative and critical study focuses not just on feminist discourses in two countries but also their relationships, suggests some viable models of transnational feminism that can preserve epistemic justice, and aims to contribute to the theoretical corpus of transnational feminism.
ContributorsChakravarty, Debjani (Author) / Kitch, Sally L (Thesis advisor) / Fonow, Mary M (Committee member) / Koblitz, Ann H (Committee member) / Arizona State University (Publisher)
Created2013
Description
This research examines the current challenges of using Lamb wave interrogation methods to localize fatigue crack damage in a complex metallic structural component subjected to unknown temperatures. The goal of this work is to improve damage localization results for a structural component interrogated at an unknown temperature, by developing a probabilistic and reference-free framework for estimating Lamb wave velocities and the damage location. The methodology for damage localization at unknown temperatures includes the following key elements: i) a model that can describe the change in Lamb wave velocities with temperature; ii) the extension of an advanced time-frequency based signal processing technique for enhanced time-of-flight feature extraction from a dispersive signal; iii) the development of a Bayesian damage localization framework incorporating data association and sensor fusion. The technique requires no additional transducers to be installed on a structure, and allows for the estimation of both the temperature and the wave velocity in the component. Additionally, the framework of the algorithm allows it to function completely in an unsupervised manner by probabilistically accounting for all measurement origin uncertainty. The novel algorithm was experimentally validated using an aluminum lug joint with a growing fatigue crack. The lug joint was interrogated using piezoelectric transducers at multiple fatigue crack lengths, and at temperatures between 20°C and 80°C. The results showed that the algorithm could accurately predict the temperature and wave speed of the lug joint. The localization results for the fatigue damage were found to correlate well with the true locations at long crack lengths, but loss of accuracy was observed in localizing small cracks due to time-of-flight measurement errors. To validate the algorithm across a wider range of temperatures the electromechanically coupled LISA/SIM model was used to simulate the effects of temperatures. The numerical results showed that this approach would be capable of experimentally estimating the temperature and velocity in the lug joint for temperatures from -60°C to 150°C. The velocity estimation algorithm was found to significantly increase the accuracy of localization at temperatures above 120°C when error due to incorrect velocity selection begins to outweigh the error due to time-of-flight measurements.
ContributorsHensberry, Kevin (Author) / Chattopadhyay, Aditi (Thesis advisor) / Liu, Yongming (Committee member) / Papandreou-Suppappola, Antonia (Committee member) / Arizona State University (Publisher)
Created2013
Description
This dissertation provides a critical analysis of public administration's understanding of the relationship between rational thought and action in its discourse on ethics. It argues that rationalist ethics assume a particular relationship between thought and action: that good knowledge leads to good, proper action. While there have been many critiques of rationalist administrative ethics, scholars have not examined the way in which rationalism persists in the way in which the teaching of ethics is conducted. The use of the case study figures prominently in this. Thus, the dissertation explores the historical and theoretical intersection of rationalism, ethics, and teaching through the lens of the case study. It begins with a history of the pedagogical use of the case study and the institutional transformations of the university. While conventional accounts of the field locate its founding in the United States in the municipal reform movement, here the founding of the field of public administration is recast through connections to reforms in the university including changes in epistemic assumptions, pedagogical methods, and curricular changes in ethics in which the case study is central and remains so as the field develops. The dissertation then considers scholarship in public administration that raises questions about rationalist ethics. Three critical approaches are explored: recognition of the uncertainty and complexity of administrative practice, critique as unmasking of power relationships, and the shift of ethics from an epistemological to an ontological inquiry. The dissertation builds on the work in this third approach and shows how it attempts to articulate a non-rationalist, or immanent, ethics. This ethics is concerned with exploring the conditions that make possible mutually beneficial relationships and meaningful lives from which categorical norms of the good life could emerge. Drawing on the philosophy of Gilles Deleuze and Felix Guattari, it is argued that the distinction Deleuze and Guattari make between "arborescent" and "rhizomatic" knowledge gets to the root of the tension between thought and action and offers an innovative and useful way to advance an immanent, non-rational ethics. The challenge digital technologies and the information society present to the field is considered to illustrate the need to rethink administrative ethics and also the particular usefulness of Deleuze and Guattari in doing so. The dissertation concludes with a discussion of pedagogical practices and classroom examples that encourage a rhizomatic understanding of the theory and practice of public administration.
ContributorsCallen, Jeffrey Craig (Author) / Catlaw, Thomas J (Thesis advisor) / Corley, Elizabeth (Committee member) / Kim, Yushim (Committee member) / Arizona State University (Publisher)
Created2013
Description
Gas turbines have become widely used in the generation of power for cities. They are used all over the world and must operate under a wide variety of ambient conditions. Every turbine has a temperature at which it operates at peak capacity. In order to attain this temperature in the hotter months various cooling methods are used such as refrigeration inlet cooling systems, evaporative methods, and thermal energy storage systems. One of the more widely used is the evaporative systems because it is one of the safest and easiest to utilize method. However, the behavior of water droplets within the inlet to the turbine has not been extensively studied or documented. It is important to understand how the droplets behave within the inlet so that water droplets above a critical diameter will not enter the compressor and cause damage to the compressor blades. In order to do this a FLUENT simulation was constructed in order to determine the behavior of the water droplets and if any droplets remain at the exit of the inlet, along with their size. In order to do this several engineering drawings were obtained from SRP and studies in order to obtain the correct dimensions. Then the simulation was set up using data obtained from SRP and Parker-Hannifin, the maker of the spray nozzles. Then several sets of simulations were run in order to see how the water droplets behaved under various conditions. These results were then analyzed and quantified so that they could be easily understood. The results showed that the possible damage to the compressor increased with increasing temperature at a constant relative humidity. This is due in part to the fact that in order to keep a constant relative humidity at varying temperatures the mass fraction of water vapor in the air must be changed. As temperature increases the water vapor mass fraction must increase in order to maintain a constant relative humidity. This in turn makes it slightly increases the evaporation time of the water droplets. This will then lead to more droplets exiting the inlet and at larger diameters.
ContributorsHargrave, Kevin (Author) / Lee, Taewoo (Thesis advisor) / Huang, Huei-Ping (Committee member) / Chen, Kaangping (Committee member) / Arizona State University (Publisher)
Created2013
Description
This study focuses on implementing probabilistic nature of material properties (Kevlar® 49) to the existing deterministic finite element analysis (FEA) of fabric based engine containment system through Monte Carlo simulations (MCS) and implementation of probabilistic analysis in engineering designs through Reliability Based Design Optimization (RBDO). First, the emphasis is on experimental data analysis focusing on probabilistic distribution models which characterize the randomness associated with the experimental data. The material properties of Kevlar® 49 are modeled using experimental data analysis and implemented along with an existing spiral modeling scheme (SMS) and user defined constitutive model (UMAT) for fabric based engine containment simulations in LS-DYNA. MCS of the model are performed to observe the failure pattern and exit velocities of the models. Then the solutions are compared with NASA experimental tests and deterministic results. MCS with probabilistic material data give a good prospective on results rather than a single deterministic simulation results. The next part of research is to implement the probabilistic material properties in engineering designs. The main aim of structural design is to obtain optimal solutions. In any case, in a deterministic optimization problem even though the structures are cost effective, it becomes highly unreliable if the uncertainty that may be associated with the system (material properties, loading etc.) is not represented or considered in the solution process. Reliable and optimal solution can be obtained by performing reliability optimization along with the deterministic optimization, which is RBDO. In RBDO problem formulation, in addition to structural performance constraints, reliability constraints are also considered. This part of research starts with introduction to reliability analysis such as first order reliability analysis, second order reliability analysis followed by simulation technique that are performed to obtain probability of failure and reliability of structures. Next, decoupled RBDO procedure is proposed with a new reliability analysis formulation with sensitivity analysis, which is performed to remove the highly reliable constraints in the RBDO, thereby reducing the computational time and function evaluations. Followed by implementation of the reliability analysis concepts and RBDO in finite element 2D truss problems and a planar beam problem are presented and discussed.
ContributorsDeivanayagam, Arumugam (Author) / Rajan, Subramaniam D. (Thesis advisor) / Mobasher, Barzin (Committee member) / Neithalath, Narayanan (Committee member) / Arizona State University (Publisher)
Created2012