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Recently, the use of zinc oxide (ZnO) nanowires as an interphase in composite materials has been demonstrated to increase the interfacial shear strength between carbon fiber and an epoxy matrix. In this research work, the strong adhesion between ZnO and carbon fiber is investigated to elucidate the interactions at the

Recently, the use of zinc oxide (ZnO) nanowires as an interphase in composite materials has been demonstrated to increase the interfacial shear strength between carbon fiber and an epoxy matrix. In this research work, the strong adhesion between ZnO and carbon fiber is investigated to elucidate the interactions at the interface that result in high interfacial strength. First, molecular dynamics (MD) simulations are performed to calculate the adhesive energy between bare carbon and ZnO. Since the carbon fiber surface has oxygen functional groups, these were modeled and MD simulations showed the preference of ketones to strongly interact with ZnO, however, this was not observed in the case of hydroxyls and carboxylic acid. It was also found that the ketone molecules ability to change orientation facilitated the interactions with the ZnO surface. Experimentally, the atomic force microscope (AFM) was used to measure the adhesive energy between ZnO and carbon through a liftoff test by employing highly oriented pyrolytic graphite (HOPG) substrate and a ZnO covered AFM tip. Oxygen functionalization of the HOPG surface shows the increase of adhesive energy. Additionally, the surface of ZnO was modified to hold a negative charge, which demonstrated an increase in the adhesive energy. This increase in adhesion resulted from increased induction forces given the relatively high polarizability of HOPG and the preservation of the charge on ZnO surface. It was found that the additional negative charge can be preserved on the ZnO surface because there is an energy barrier since carbon and ZnO form a Schottky contact. Other materials with the same ionic properties of ZnO but with higher polarizability also demonstrated good adhesion to carbon. This result substantiates that their induced interaction can be facilitated not only by the polarizability of carbon but by any of the materials at the interface. The versatility to modify the magnitude of the induced interaction between carbon and an ionic material provides a new route to create interfaces with controlled interfacial strength.
ContributorsGalan Vera, Magdian Ulises (Author) / Sodano, Henry A (Thesis advisor) / Jiang, Hanqing (Committee member) / Solanki, Kiran (Committee member) / Oswald, Jay (Committee member) / Speyer, Gil (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Wind measurements are fundamental inputs for the evaluation of potential energy yield and performance of wind farms. Three-dimensional scanning coherent Doppler lidar (CDL) may provide a new basis for wind farm site selection, design, and control. In this research, CDL measurements obtained from multiple wind energy developments are analyzed and

Wind measurements are fundamental inputs for the evaluation of potential energy yield and performance of wind farms. Three-dimensional scanning coherent Doppler lidar (CDL) may provide a new basis for wind farm site selection, design, and control. In this research, CDL measurements obtained from multiple wind energy developments are analyzed and a novel wind farm control approach has been modeled. The possibility of using lidar measurements to more fully characterize the wind field is discussed, specifically, terrain effects, spatial variation of winds, power density, and the effect of shear at different layers within the rotor swept area. Various vector retrieval methods have been applied to the lidar data, and results are presented on an elevated terrain-following surface at hub height. The vector retrieval estimates are compared with tower measurements, after interpolation to the appropriate level. CDL data is used to estimate the spatial power density at hub height. Since CDL can measure winds at different vertical levels, an approach for estimating wind power density over the wind turbine rotor-swept area is explored. Sample optimized layouts of wind farm using lidar data and global optimization algorithms, accounting for wake interaction effects, have been explored. An approach to evaluate spatial wind speed and direction estimates from a standard nested Coupled Ocean and Atmosphere Mesoscale Prediction System (COAMPS) model and CDL is presented. The magnitude of spatial difference between observations and simulation for wind energy assessment is researched. Diurnal effects and ramp events as estimated by CDL and COAMPS were inter-compared. Novel wind farm control based on incoming winds and direction input from CDL's is developed. Both yaw and pitch control using scanning CDL for efficient wind farm control is analyzed. The wind farm control optimizes power production and reduces loads on wind turbines for various lidar wind speed and direction inputs, accounting for wind farm wake losses and wind speed evolution. Several wind farm control configurations were developed, for enhanced integrability into the electrical grid. Finally, the value proposition of CDL for a wind farm development, based on uncertainty reduction and return of investment is analyzed.
ContributorsKrishnamurthy, Raghavendra (Author) / Calhoun, Ronald J (Thesis advisor) / Chen, Kangping (Committee member) / Huang, Huei-Ping (Committee member) / Fraser, Matthew (Committee member) / Phelan, Patrick (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Unauthorized immigrants account for approximately one fourth of all immigrants in the United States, yet they dominate public perceptions and are at the heart of a policy impasse. Caught in the middle are the children of these immigrants--youth who are coming of age and living in the shadows; they are

Unauthorized immigrants account for approximately one fourth of all immigrants in the United States, yet they dominate public perceptions and are at the heart of a policy impasse. Caught in the middle are the children of these immigrants--youth who are coming of age and living in the shadows; they are an invisible cohort. An estimated 5.5 million children and adolescents are growing up with unauthorized immigrant parents, and are experiencing multiple, and yet unrecognized developmental consequences of their families' existence in the shadow of the law. Although these youth are American in spirit and voice, they are, nonetheless, members of families that are "illegal" in the eyes of the law. Many children have been exiled to México; these are the children living in the shadows of Mexican diaspora, Los Retornos. This phenomenological study developed a conceptual framework to examine the effects in which being an exiled United States citizen living in Morelia, Michoacán, affected these many children and adolescents. Bourdieu's (1977) theoretical framework is used in this study and is based on his social, cultural capital concept; the assumption is that Los Retornos carry valuable sociocultural, bilingual and monoliterate capital that is endangered, unrecognized, replaceable, and not used to the best interest of students in schools. This study made use of this framework to answer the following questions: 1. How do Retorno families (nuclear and extended) develop the self-efficacy needed to preserve the social and cultural capital they bring with them to Michoacán? 2. How are communities and identity forms imagined and created in the context of this new migration shift? 3. How are Los Retornos responding to the involuntary shift (N=7) from the U.S to Michoacán? 4. How are teachers adjusting their classroom practices and curriculum to meet the academic needs of Los Retornos? The purpose of this qualitative phenomenological study is to improve understanding of Los Retornos. This phenomenological case study is focused on identifying experiences Los Retornos encounter in their schools and family lives through their personal migration experience to illuminate how best to help them preserve the social and cultural, capital they bring with them. The findings from this study may assist educators and policy makers in developing interventions and policies that meet the needs of this cohort.
ContributorsQuezada Sanders, Irene Genevieve (Author) / Ovando, Carlos J. (Thesis advisor) / Mccarty, Teresa L. (Committee member) / De Los Santos Jr., Alfredo G. (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Examining the elements of the hidden curriculum in theatre education allows theatre educators the opportunity to reflect on their own pedagogy and its effects on the learner. The hidden curriculum refers to the unspoken or implicit values, norms, and beliefs that are transmitted through tacit messages. When the hidden curriculum

Examining the elements of the hidden curriculum in theatre education allows theatre educators the opportunity to reflect on their own pedagogy and its effects on the learner. The hidden curriculum refers to the unspoken or implicit values, norms, and beliefs that are transmitted through tacit messages. When the hidden curriculum remains veiled, the impact on the learner's education and socialization process can perpetuate gender, race, and class inequalities. In order to understand how the hidden curriculum manifests itself in theatre classrooms, we have to look at schools as "agents of legitimation, organized to produce and reproduce the dominant categories, values, and social relationships necessary for the maintenance of the larger society" (Giroux, 1983, p. 72). This qualitative study examined the hidden curriculum in theatre at the secondary level and looked at theatre teachers' pedagogy in reproducing elements of the hidden curriculum. Interviews, naturalistic observation, and a researcher reflective journal were employed in the data collection process to better understand: a) the elements of hidden curriculum that appear in theatre education at the secondary level, b) how the pedagogical practices of theatre teachers support societal structures, and c) how the hidden curriculum in theatre reinforces gender, race, and social class distinctions. Data were then coded and analyzed to find emergent themes. Multiple theoretical perspectives serve as a conceptual framework for understanding the hidden curriculum, and provide a neglected perspective of the hidden curriculum in theatre education. The theatre classroom provides a unique space to view hidden curriculum and can be viewed as a unique agent of social change. Themes related to the first research question emerged as: a) privileges for older students, b) school rules, c) respect for authority, d) acceptance of repetitive tasks, and c) punctuality. Themes related to the second research question emerged as: a) practices, b) procedures, c) rules, d) relationships, and e) structures. Finally, themes related to the third question emerged as: a) reinforcement of social inequality, b) perpetuation of class structure, and c) acceptance of social destiny. The discussion looks at the functions of theatre pedagogy in the reproduction of class, inequality, and institutionalized cultural norms.
ContributorsHines, Angela R (Author) / Saldana, Johnny (Thesis advisor) / Malewski, Erik (Committee member) / Fischman, Gustavo (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Teacher attrition and the migration between schools and districts can have a negative impact on quality of education and teacher performance. Novice teachers leave the profession because they are overwhelmed by the workload and responsibilities of the job. In a previous action research cycle, I found that novice teachers' perceptions

Teacher attrition and the migration between schools and districts can have a negative impact on quality of education and teacher performance. Novice teachers leave the profession because they are overwhelmed by the workload and responsibilities of the job. In a previous action research cycle, I found that novice teachers' perceptions of isolation and lack of opportunities to share experiences had a negative effect on teacher perceptions of efficacy. This action research project examines the effect of leveraging social media and professional learning communities to provide opportunities for a group of novice teachers to share experiences and seek advice. By addressing the challenges that novice teachers face and providing solutions for common problems, it is the hope of this researcher that highly effective teachers will remain in the classroom. The results of the study indicate that the combined use of Twitter and YouTube in collaboration with professional learning communities will improve teacher perceptions of efficacy. Teachers who participated in the social media based professional learning communities are also more likely to remain in the classroom.
ContributorsBostick, Bradley Alan (Author) / Zambo, Ronald (Thesis advisor) / Heck, Thomas (Committee member) / Isai, Shelley (Committee member) / Arizona State University (Publisher)
Created2013
ContributorsWard, Geoffrey Harris (Performer) / ASU Library. Music Library (Publisher)
Created2018-03-18
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Description
The purpose of this study was to examine the attitudes and opinions of Navajo students toward the Navajo language and culture programs within the schools they were attending. Although in the final year of the No Child Left Behind, a majority of the 265 schools on and near the Navajo

The purpose of this study was to examine the attitudes and opinions of Navajo students toward the Navajo language and culture programs within the schools they were attending. Although in the final year of the No Child Left Behind, a majority of the 265 schools on and near the Navajo reservation have not been making Adequate Yearly Progress, a concern for the parents, teachers, administrators, school board members, and the Navajo Nation. The study entailed conducting a survey at five schools; three of which were not meeting the requirements of the No Child Left Behind. The purpose of the survey instrument (27 questions) administered to the students at the five schools was to examine their attitudes and opinions as to participating in Navajo language and culture programs, to determine if the programs assisted them in their academic achievements, and to examine whether these programs actually made a difference for schools in their Adequate Yearly Progress requirement Approximately 87% of 99 Navajo students, 55 boys and 58 girls, ages 9 through 14, Grades 3 through 8, who lived off the reservation in Flagstaff, Arizona and Gallup, New Mexico, and took the survey knew and spoke Navajo, but less fluently and not to a great extent. However, the students endorsed learning Navajo and strongly agreed that the Navajo language and culture should be part of the curriculum. Historically there have been schools such as the Rock Point Community School, Rough Rock Demonstration School, Borrego Pass Community School, and Ramah Community School that have been successful in their implementation of bilingual programs. The question presently facing Navajo educators is what type of programs would be successful within the context of the No Child Left Behind federal legislation. Can there be replications of successful Navajo language and culture programs into schools that are not making Adequate Yearly Progress?
ContributorsTsosie, David J (Author) / Spencer, Dee A. (Thesis advisor) / Appleton, Nicholas A. (Committee member) / Koerperich, Robbie (Committee member) / Arizona State University (Publisher)
Created2013
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Description
In this dissertation I attempt to find elements of education and curricular perspective in the Qur'an. I argue that there is little research in the field of curriculum instruction that discusses the Qur'an's educational aspects and, as a result, much ignorance of the Qur'an's material that deals with education and

In this dissertation I attempt to find elements of education and curricular perspective in the Qur'an. I argue that there is little research in the field of curriculum instruction that discusses the Qur'an's educational aspects and, as a result, much ignorance of the Qur'an's material that deals with education and curricular perspective in the Qur'an. Researchers may find many materials that deal with reading, memorizing, and reciting the Qur'an, along with references that deal with science and math in the Qur'an. Therefore, this dissertation answers the question: What curriculum exists within the Quran? This dissertation is divided into five chapters exploring various aspects of the curriculum. The word "curriculum" is used in one chapter to mean developing the person as a whole in all aspects of life whether spiritual, social, or mental while in the other chapter curriculum is used to refer to methods of instruction. I concluded that curriculum in the Qur'an uses different methods of instructions to develop the individual as a whole in all aspects of life while granting freedom of choice.
ContributorsRisha, Sarah (Author) / Margolis, Eric (Thesis advisor) / Fischman, Gustavo (Committee member) / Ali, Souad (Committee member) / Arizona State University (Publisher)
Created2013
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Description
ABSTRACT This study describes student interactions in the academic social network site Edmodo versus student interactions in Facebook. This qualitative case study relies upon four high school juniors enrolled in Advanced Placement Language and Composition who use Edmodo to complete assignments for their English class. Their experiences were gathered in

ABSTRACT This study describes student interactions in the academic social network site Edmodo versus student interactions in Facebook. This qualitative case study relies upon four high school juniors enrolled in Advanced Placement Language and Composition who use Edmodo to complete assignments for their English class. Their experiences were gathered in an attempt to describe specific experiences in a complex system. Students were selected using an Internet Connectedness Index survey. Using a Virtual Community of Practice framework, students were asked about their experiences in Edmodo. This study concludes that Edmodo and Facebook can be compared in three categories: accessibility, functionality, and environment. Unlike Facebook, which students access regularly, students access Edmodo only to fulfill the teacher's participation expectations for the specific grade they wish to receive. Additionally, students appreciated the convenience of using Edmodo to complete assignments. The functionality of Edmodo is quite similar in layout and appearance to Facebook, yet students were unaware of the media sharing capability, wished for private messaging options, and desired the ability to tag peers for direct comment using the @ sign, all options that are available in Facebook. Students felt the environment in Edmodo could best be characterized as intellectual and academic, which some mentioned might best be used with honors or AP students. A surprising benefit of Edmodo is the lack of social cues enable students to feel free of judgment when composing writing. Some felt this allowed students to know their classmates better and share their true personae free from judgment of classmates. As a result of the case studies of four students, this study seeks to illustrate how students interact in Edmodo versus Facebook to provide a robust image of the academic social network site for teachers seeking to implement educational technology in their classes.
ContributorsCurran-Sejkora, Elizabeth (Author) / Blasingame, James (Thesis advisor) / Nilsen, Alleen (Committee member) / Rodrigo, Rochelle (Committee member) / Turchi, Laura (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Production from a high pressure gas well at a high production-rate encounters the risk of operating near the choking condition for a compressible flow in porous media. The unbounded gas pressure gradient near the point of choking, which is located near the wellbore, generates an effective tensile stress on the

Production from a high pressure gas well at a high production-rate encounters the risk of operating near the choking condition for a compressible flow in porous media. The unbounded gas pressure gradient near the point of choking, which is located near the wellbore, generates an effective tensile stress on the porous rock frame. This tensile stress almost always exceeds the tensile strength of the rock and it causes a tensile failure of the rock, leading to wellbore instability. In a porous rock, not all pores are choked at the same flow rate, and when just one pore is choked, the flow through the entire porous medium should be considered choked as the gas pressure gradient at the point of choking becomes singular. This thesis investigates the choking condition for compressible gas flow in a single microscopic pore. Quasi-one-dimensional analysis and axisymmetric numerical simulations of compressible gas flow in a pore scale varicose tube with a number of bumps are carried out, and the local Mach number and pressure along the tube are computed for the flow near choking condition. The effects of tube length, inlet-to-outlet pressure ratio, the number of bumps and the amplitude of the bumps on the choking condition are obtained. These critical values provide guidance for avoiding the choking condition in practice.
ContributorsYuan, Jing (Author) / Chen, Kangping (Thesis advisor) / Wang, Liping (Committee member) / Huang, Huei-Ping (Committee member) / Arizona State University (Publisher)
Created2013