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: Aerospace Engineering
Description
I study the performance of hedge fund managers, using quarterly stock holdings from 1995 to 2010. I use the holdings-based measure built on Ferson and Mo (2012) to decompose a manager's overall performance into stock selection and three components of timing ability: market return, volatility, and liquidity. At the aggregate level, I find that hedge fund managers have stock picking skills but no timing skills, and overall I do not find strong evidence to support their superiority. I show that the lack of abilities is driven by the large fluctuations of timing performance with market conditions. I find that conditioning information, equity capital constraints, and priority in stocks to liquidate can partly explain the weak evidence. At the individual fund level, bootstrap analysis results suggest that even top managers' abilities cannot be separated from luck. Also, I find that hedge fund managers exhibit short-horizon persistence in selectivity skill.
ContributorsKang, MinJeong (Author) / Aragon, George O. (Thesis advisor) / Hertzel, Michael G (Committee member) / Boguth, Oliver (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 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
"YouTube Shakespeares" is a study of Shakespeare online videos and the people who create, upload, and view them on YouTube. Employing an interdisciplinary approach, this work is a remix of theories and methodologies from literary, performance, (social) media, fan, and Internet studies that expands the field of Shakespeare studies. This dissertation explores the role of YouTube users and their activities, the expansion of literary research methods onto digital media venues, YouTube as site of Shakespeare performance, and YouTube Shakespeares' fan communities. It analyzes a broad array of Shakespeare visual performances including professional and user-generated mashups, remixes, film clips, auditions, and high school performances. A rich avenue for the study of people's viewing and reception of Shakespeare, YouTube tests the (un)limitations of Shakespeare adaptation. This work explores the ethical implications of researching performances that include human subjects, arguing that their presence frequently complicates common concepts of public and private identities. Although YouTube is a "published" forum for social interactivity and video repository, this work urges digital humanities scholars to recognize and honor the human users entailed in the videos not as text, but as human subjects. Shifting the study focus to human subjects demands a revision of research methods and publications protocols as the researcher repositions herself into the role of virtual ethnographer. "YouTube Shakespeares" develops its own ethics-based, online research method, which includes seeking Institutional Board Review approval and online interviews. The second half of the dissertation shifts from methodology to theorizing YouTube Shakespeares' performance spaces as analogs to the interactive and imaginary areas of Shakespeare's early modern theatre. Additionally, this work argues that YouTube Shakespeares' creators and commentators are fans. "YouTube Shakespeares" is one of the first Shakespeare-centric studies to employ fan studies as a critical lens to explore the cultural significance and etiquette of people's online Shakespeare performance activities. The work ends with a conversation about the issues of ephemerality, obsolescence, and concerns about the instability of digital and online materials, noting the risk of evidentiary loss of research materials is far outweighed by a scholarly critical registration of YouTube in the genealogy of Shakespeare performance.
ContributorsFazel, Valerie Margaret (Author) / Thompson, Ayanna (Thesis advisor) / Ryner, Bradley (Committee member) / Fox, Cora (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
The integration of yoga into the music curriculum has the potential of offering many immediate and life-long benefits to musicians. Yoga can help address issues such as performance anxiety and musculoskeletal problems, and enhance focus and awareness during musical practice and performance. Although the philosophy of yoga has many similarities to the process of learning a musical instrument, the benefits of yoga for musicians is a topic that has gained attention only recently. This document explores several ways in which the practice and philosophy of yoga can be fused with saxophone pedagogy as one way to prepare students for a healthy and successful musical career. A six-week study at Arizona State University was conducted to observe the effects of regular yoga practice on collegiate saxophone students. Nine participants attended a sixty-minute "yoga for musicians" class twice a week. Measures included pre- and post- study questionnaires as well as personal journals kept throughout the duration of the study. These self-reported results showed that yoga had positive effects on saxophone playing. It significantly increased physical comfort and positive thinking, and improved awareness of habitual patterns and breath control. Student participants responded positively to the idea of integrating such a course into the music curriculum. The integration of yoga and saxophone by qualified professionals could also be a natural part of studio class and individual instruction. Carrie Koffman, professor of saxophone at The Hartt School, University of Hartford, has established one strong model for the combination of these disciplines. Her methods and philosophy, together with the basics of Western-style hatha yoga, clinical reports on performance injuries, and qualitative data from the ASU study are explored. These inquiries form the foundation of a new model for integrating yoga practice regularly into the saxophone studio.
ContributorsAdams, Allison Dromgold (Author) / Norton, Kay (Thesis advisor) / Hill, Gary (Committee member) / McAllister, Timothy (Committee member) / Micklich, Albie (Committee member) / Standley, Eileen (Committee member) / Arizona State University (Publisher)
Created2012
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
Description
The Holocaust and the effects it has had upon witnesses has been a topic of study for nearly six decades; however, few angles of research have been conducted relating to the long-term effects of the Holocaust upon the children and grandchildren of Holocaust survivors--the After Generations. The After Generations are considered the proof--the living legacies--that their parents and grandparents survived. Growing up with intimate knowledge of the atrocities that occurred during the Holocaust, members of the After Generations not only carry with them their family's story, but also their own vicarious experience(s) of trauma. From this legacy comes a burden of responsibility to those who perished, their survivor parents/grandparents, the stories that were shared, as well as to future generations. Using grounded theory method, this study not only explores the long-term effects of the Holocaust upon members of the After Generations, but what it means to responsibly remember the stories from the Holocaust, as well as how individuals might ethically represent such stories/memories. Findings that developed out of an axial analysis of interview transcripts and journal writing, as well as the later development of a performance script, are embodied in a manner that allows the actual language and experiences of the participants to be collectively witnessed both symbolically and visually. Through their desire to remember, members of the After Generations demonstrate how they plan to carry on traditions, live lives that honor those that came before them, and maintain hope for the future. In so doing, the stories shared reveal the centrality of the Holocaust in the lives of members of the After Generations through their everyday choices to responsibly and actively remember through their art, writings, life-work, as well as from within their work in their local communities. Such acts of remembrance are important to the education of others as well as to the construction and maintenance of the After Generations' identities. The representation of these voices acts as a reminder of how hatred and its all-consuming characteristics can affect not only the person targeted, but multiple generations, as well.
ContributorsRath, Sandra (Author) / de la Garza, Sarah Amira (Thesis advisor) / Underiner, Tamara (Committee member) / Corey, Frederick C. (Committee member) / Eisenberg, Judith (Committee member) / Arizona State University (Publisher)
Created2012