Matching Items (67)
Description
The object of this study was a 26 year old residential Photovoltaic (PV) monocrystalline silicon (c-Si) power plant, called Solar One, built by developer John F. Long in Phoenix, Arizona (a hot-dry field condition). The task for Arizona State University Photovoltaic Reliability Laboratory (ASU-PRL) graduate students was to evaluate the power plant through visual inspection, electrical performance, and infrared thermography. The purpose of this evaluation was to measure and understand the extent of degradation to the system along with the identification of the failure modes in this hot-dry climatic condition. This 4000 module bipolar system was originally installed with a 200 kW DC output of PV array (17 degree fixed tilt) and an AC output of 175 kVA. The system was shown to degrade approximately at a rate of 2.3% per year with no apparent potential induced degradation (PID) effect. The power plant is made of two arrays, the north array and the south array. Due to a limited time frame to execute this large project, this work was performed by two masters students (Jonathan Belmont and Kolapo Olakonu) and the test results are presented in two masters theses. This thesis presents the results obtained on the north array and the other thesis presents the results obtained on the south array. The resulting study showed that PV module design, array configuration, vandalism, installation methods and Arizona environmental conditions have had an effect on this system's longevity and reliability. Ultimately, encapsulation browning, higher series resistance (potentially due to solder bond fatigue) and non-cell interconnect ribbon breakages outside the modules were determined to be the primary causes for the power loss.
ContributorsBelmont, Jonathan (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Henderson, Mark (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2013
Description
The use of educational technologies as a tool to improve academic achievement continues to increase as more technologies becomes available to students. However, teachers are entering the classroom not fully prepared to integrate technology into their daily classroom teaching because they have not been adequately prepared to do so. Teacher preparation programs are falling short in this area because educational technology and the role of technology in the classroom is seen as an extra component to daily teaching rather than a central one. Many teacher preparation programs consist of one stand-alone educational technology course that is expected to prepare teachers to integrate technology in their future classrooms. Throughout the remainder of the program, the teachers are not seeing educational technologies modeled in their other core courses, nor are they getting the hands-on interaction necessary to become more confident in using these technologies with their future students. The purpose of this study was to examine teachers' views of educational technology in the classroom from those enrolled in a graduate program. The study consisted 74 first- and second-year teachers who were enrolled an alternative teacher preparation program. Thirty-four of the teachers received the Integrating Curriculum and Technology (iCAT) intervention and the remaining 40 teachers were part of the control group. Each teacher completed a pre- and post-intervention questionnaire and 23 of the 74 teachers participated in one of three focus group interviews. Additional data from the teachers' course instructors were gathered and analyzed to compliment the focus group and quantitative data. Results showed that iCAT participants' scores for confidence in using technology and efficacy for using educational technology increased at a faster rate than the control group participants' scores. Similarly, confidence in using technology, perceptions about integrating technology in the classroom, and efficacy for using educational technology could be predicted by the amount of hands-on interaction with technology that the teachers received during their graduate course. The discussion focuses on recommendations for infusing technology throughout teacher preparation programs so that teachers have the tools to prepare their students to use a variety of technologies so that their students can be better prepared to complete in today's workforce.
ContributorsKisicki, Todd (Author) / Wetzel, Keith (Thesis advisor) / Bitter, Gary (Thesis advisor) / Buss, Ray (Committee member) / Savenye, Wilhelmina (Committee member) / Arizona State University (Publisher)
Created2012
Description
Microalgae represent a potential sustainable alternative for the enhancement and protection of agricultural crops. The dry biomass and cellular extracts of Scenedesmus dimorphus were applied as a biofertilizer, a foliar spray, and a seed primer to evaluate seed germination, plant growth, and crop yield of Roma tomato plants. The dry biomass was applied as a biofertilizer at 50 g and 100 g per plant, to evaluate its effects on plant development and crop yield. Biofertilizer treatments enhanced plant growth and led to greater crop (fruit) production. Timing of biofertilizer application proved to be of importance - earlier 50 g biofertilizer application resulted in greater plant growth. Scenedesmus dimorphus culture, growth medium, and different concentrations (1%, 5%, 10%, 25%, 50%, 75%, 100%) of aqueous cell extracts were used as seed primers to determine effects on germination. Seeds treated with Scenedesmus dimorphus culture and with extract concentrations higher than 50 % (0.75 g ml-1) triggered faster germination - 2 days earlier than the control group. Extract foliar sprays of 50 ml and 100 ml, were obtained and applied to tomato plants at various extract concentrations (10%, 25%, 50%, 75% and 100%). Plant height, flower development and number of branches were significantly enhanced with 50 % (7.5 g ml-1) extracts. Higher concentration sprays led to a decrease in growth. The extracts were further screened to assess potential antimicrobial activity against the bacterium Escherichia coli ATCC 25922, the fungi Candida albicans ATCC 90028 and Aspergillus brasiliensis ATCC 16404. No antimicrobial activity was observed from the microalga extracts on the selected microorganisms.
ContributorsGarcia-Gonzalez, Jesus (Author) / Sommerfeld, Milton (Thesis advisor) / Steele, Kelly (Committee member) / Henderson, Mark (Committee member) / Arizona State University (Publisher)
Created2014
Description
This study explores teacher educators' personal theories about the instructional practices central to preparing future teachers, how they enact those personal theories in the classroom, how they represent the relationship between content, pedagogy, and technology, and the function of technology in teacher educators' personal theories about the teaching of mathematics and their practices as enacted in the classroom. The conceptual frameworks of knowledge as situated and technology as situated provide a theoretical and analytical lens for examining individual instructor's conceptions and classroom activity as situated in the context of experiences and relationships in the social world. The research design employs a mixed method design to examine data collected from a representative sample of three full-time faculty members teaching methods of teaching mathematics in elementary education at the undergraduate level. Three primary types of data were collected and analyzed:
a) structured interviews using the repertory grid technique to model the mathematics education instructors' schemata regarding the teaching of mathematics methods; b) content analysis of classroom observations to develop models that represent the relationship of pedagogy, content, and technology as enacted in the classrooms; and c) brief retrospective protocols after each observed class session to explore the reasoning and individual choices made by an instructor that underlie their teaching decisions in the classroom. Findings reveal that although digital technology may not appear to be an essential component of an instructor's toolkit, technology can still play an integral role in teaching. This study puts forward the idea of repurposing as technology -- the ability to repurpose items as models, tools, and visual representations and integrate them into the curriculum. The instructors themselves became the technology, or the mediational tool, and introduced students to new meanings for "old" cultural artifacts in the classroom. Knowledge about the relationships between pedagogy, content, and technology and the function of technology in the classroom can be used to inform professional development for teacher educators with the goal of improving teacher preparation in mathematics education.
a) structured interviews using the repertory grid technique to model the mathematics education instructors' schemata regarding the teaching of mathematics methods; b) content analysis of classroom observations to develop models that represent the relationship of pedagogy, content, and technology as enacted in the classrooms; and c) brief retrospective protocols after each observed class session to explore the reasoning and individual choices made by an instructor that underlie their teaching decisions in the classroom. Findings reveal that although digital technology may not appear to be an essential component of an instructor's toolkit, technology can still play an integral role in teaching. This study puts forward the idea of repurposing as technology -- the ability to repurpose items as models, tools, and visual representations and integrate them into the curriculum. The instructors themselves became the technology, or the mediational tool, and introduced students to new meanings for "old" cultural artifacts in the classroom. Knowledge about the relationships between pedagogy, content, and technology and the function of technology in the classroom can be used to inform professional development for teacher educators with the goal of improving teacher preparation in mathematics education.
ContributorsToth, Meredith Jean (Author) / Middleton, James (Thesis advisor) / Sloane, Finbarr (Committee member) / Buss, Ray (Committee member) / Atkinson, Robert (Committee member) / Arizona State University (Publisher)
Created2014
Description
Haiti has witnessed high deforestation rates in recent decades, caused largely by the fuel needs of a growing population. The resulting soil loss is estimated to have contributed towards a decline in agricultural productivity of 0.5% -1.2% per year since 1997. Recent studies show the potential of biochar use through pyrolysis technology to increase crop yields and improve soil health. However, the appropriateness of this technology in the context of Haiti remains unexplored. The three objectives of this research were to identify agricultural- and fuel-use-related needs and gaps in rural Haitian communities; determine the appropriateness of biochar pyrolyzer technology, used to convert agricultural biomass into a carbon-rich charcoal; and develop an action-oriented plan for use by development organizations, communities, and governmental institutions to increase the likelihood of adoption. Data were collected using participatory rural appraisal techniques involving 30 individual interviews and three focus-group discussions in the villages of Cinquantin and La Boule in the La Coupe region of central Haiti. Topics discussed include agricultural practices and assets, fuel use and needs, technology use and adoption, and social management practices. The Sustainable Livelihoods framework was used to examine the assets of households and the livelihood strategies being employed. Individual and focus group interviews were analyzed to identify specific needs and gaps. E.M. Rogers' Diffusion of Innovations theory was used to develop potential strategies for the introduction of pyrolysis technology. Preliminary results indicate biochar pyrolysis has potential to address agricultural and fuel needs in rural Haiti. Probable early adopters of biochar technology include households that have adopted new agricultural techniques in the past, and those with livestock. Education about biochar, and a variety of pyrolysis technology options from which villagers may select, are important factors in successful adoption of biochar use. A grain mill as an example in one of the study villages provides a model of ownership and use of pyrolysis technology that may increase its likelihood of successful adoption. Additionally, women represent a group that may be well suited to control a new local biochar enterprise, potentially benefiting the community.
ContributorsDelaney, Michael Ryan (Author) / Aggarwal, Rimjhim (Thesis advisor) / Chhetri, Nalini (Committee member) / Henderson, Mark (Committee member) / Arizona State University (Publisher)
Created2011
Description
While the implementation of both mild hybrid and start-stop technology is widespread as a factory option in newer vehicles, the adaptation of hybrid technology to older or unequipped vehicles has not been fully realized. As such, a straight forward hybrid conversion system that is easily adapted to different vehicles regardless of drivetrain configuration, has been developed and applied to a test vehicle for less than $2,000. System performance was recorded both before and after hybridization using real world drive cycle tracking charts. The vehicle established a fuel economy baseline of 22.93 mpg, and achieved 26.58 mpg after the conversion. This corresponds to a 15.92% increase in fuel economy. Accounting for initial system costs and annual fuel saving, this corresponds to a 6-year payback period. Based on these results, it can be concluded that an inexpensive aftermarket hybrid system is both feasible and effective at improving fuel economy.
ContributorsBeeney, Tyler (Author) / Rogers, Bradley (Thesis advisor) / Madakannan, Arunachalanadar (Committee member) / Henderson, Mark (Committee member) / Arizona State University (Publisher)
Created2012
Description
Mostly, manufacturing tolerance charts are used these days for manufacturing tolerance transfer but these have the limitation of being one dimensional only. Some research has been undertaken for the three dimensional geometric tolerances but it is too theoretical and yet to be ready for operator level usage. In this research, a new three dimensional model for tolerance transfer in manufacturing process planning is presented that is user friendly in the sense that it is built upon the Coordinate Measuring Machine (CMM) readings that are readily available in any decent manufacturing facility. This model can take care of datum reference change between non orthogonal datums (squeezed datums), non-linearly oriented datums (twisted datums) etc. Graph theoretic approach based upon ACIS, C++ and MFC is laid out to facilitate its implementation for automation of the model. A totally new approach to determining dimensions and tolerances for the manufacturing process plan is also presented. Secondly, a new statistical model for the statistical tolerance analysis based upon joint probability distribution of the trivariate normal distributed variables is presented. 4-D probability Maps have been developed in which the probability value of a point in space is represented by the size of the marker and the associated color. Points inside the part map represent the pass percentage for parts manufactured. The effect of refinement with form and orientation tolerance is highlighted by calculating the change in pass percentage with the pass percentage for size tolerance only. Delaunay triangulation and ray tracing algorithms have been used to automate the process of identifying the points inside and outside the part map. Proof of concept software has been implemented to demonstrate this model and to determine pass percentages for various cases. The model is further extended to assemblies by employing convolution algorithms on two trivariate statistical distributions to arrive at the statistical distribution of the assembly. Map generated by using Minkowski Sum techniques on the individual part maps is superimposed on the probability point cloud resulting from convolution. Delaunay triangulation and ray tracing algorithms are employed to determine the assembleability percentages for the assembly.
ContributorsKhan, M Nadeem Shafi (Author) / Phelan, Patrick E (Thesis advisor) / Montgomery, Douglas C. (Committee member) / Farin, Gerald (Committee member) / Roberts, Chell (Committee member) / Henderson, Mark (Committee member) / Arizona State University (Publisher)
Created2011
Description
This paper addresses a local problem of practice at Arizona State University regarding the support for potentially underprepared students. The overarching goal of this study was to better understand the role rapport plays in student achievement. This study examines how the LEAD Project (Learn, Explore, Advance, Design), in particular student relationships with instructors and their peers, may or may not influence student achievement. LEAD students complete three courses as a group – Introduction to Human Communication (COM 100), Critical Reading and Thinking (UNI 110), and The LEAD Project (ASU 150). The innovation was designed to give students the opportunity to build relationships with their instructors and with each other, so class sizes are limited to 40 students. Additionally, instructors work together outside of class to develop curriculum, instructional plans, and how to best support individual students.
Guiding literature for this study included Self-Determination Theory (SDT) as well as related studies (Deci & Flaste, 1995). This theory describes human motivation as a factor of the extent to which one feels autonomy, competence, and relatedness. Though relevant in many contexts, past researchers used SDT as a tool for understanding students’ motivation to learn (Black & Deci, 2000; Freiberger, Steinmayr, & Spinath, 2012; Reeve & Jang, 2006).
The study used a concurrent mixed-method action research design including interviews, questionnaires, and institutional data. Over 400 first-year students participated in the study. Students shared their perceptions of their rapport with their instructors and peers, and their perceived learning in each of the three LEAD courses.
Data were analyzed using correlation and linear regression approaches. Significant relations occurred between many instructor-student rapport scales, peer rapport, perceived learning, and course grades. Additionally, instructor-student rapport scales significantly predicted perceived learning.
Qualitative and quantitative findings were aligned with each other, and were consistent with previous studies. This study advances the body of knowledge about instructor-student rapport by extending the findings around its role in student achievement. Results also suggested the need to further explore the role of peer rapport and its influence on student achievement. Results from the study show instructor-student rapport was mediators of student achievement.
Guiding literature for this study included Self-Determination Theory (SDT) as well as related studies (Deci & Flaste, 1995). This theory describes human motivation as a factor of the extent to which one feels autonomy, competence, and relatedness. Though relevant in many contexts, past researchers used SDT as a tool for understanding students’ motivation to learn (Black & Deci, 2000; Freiberger, Steinmayr, & Spinath, 2012; Reeve & Jang, 2006).
The study used a concurrent mixed-method action research design including interviews, questionnaires, and institutional data. Over 400 first-year students participated in the study. Students shared their perceptions of their rapport with their instructors and peers, and their perceived learning in each of the three LEAD courses.
Data were analyzed using correlation and linear regression approaches. Significant relations occurred between many instructor-student rapport scales, peer rapport, perceived learning, and course grades. Additionally, instructor-student rapport scales significantly predicted perceived learning.
Qualitative and quantitative findings were aligned with each other, and were consistent with previous studies. This study advances the body of knowledge about instructor-student rapport by extending the findings around its role in student achievement. Results also suggested the need to further explore the role of peer rapport and its influence on student achievement. Results from the study show instructor-student rapport was mediators of student achievement.
ContributorsVawter, Katherine (Author) / Kulinna, Pamela (Thesis advisor) / Buss, Ray (Committee member) / Potts, Shelly (Committee member) / Arizona State University (Publisher)
Created2018
Description
Teacher shortage crisis were consistent across the nation. Higher education institutions, K-12 school districts, and political leaders were actively seeking solutions to ensure classrooms did not sit vacant and were not staffed by individuals who are unqualified to teach. This mixed methods action research study examined one strategy for teacher recruitment by targeting high school students who attended a Title 1 school. Due to the growing Hispanic population in Arizona, coupled with the underrepresentation of Hispanic teachers compared to the number of Hispanic students, a particular focus was devoted to targeting Hispanic high school students as they represented a potential untapped pipeline of future educators. The study was conducted to explore factors that might increase student interest in declaring education as a major upon graduating from high school and eventually pursuing teaching as a career. Three theoretical frameworks guided the study: (a) Theory of Planned Behavior, (b) Self-Efficacy, and (c) Social Cognitive Career Theory. A total of 20 participants engaged in the intervention over the course of three weeks. The intervention included engagement in curriculum exposing students to the teaching profession as well as clinical experiences. Data gathered included pre- and post- intervention survey results and semi-structured interview questions. It was anticipated the intervention would increase students’ interest in becoming a teacher. Results demonstrated a decrease in intention post-intervention. Future research should examine alternative recruitment approaches for students who do not already have an interest in pursuing the profession.
ContributorsDiaz, Elora Denae (Author) / Buss, Ray (Thesis advisor) / Borden, Ryen (Committee member) / Preach, Deborah (Committee member) / Arizona State University (Publisher)
Created2019
Description
How does a university create a culture of affinity where students seek and maintain life-long connections to the institution? The purpose of this action research study was to examine how affinity increased or developed for undergraduate students at the Arizona State University Polytechnic campus through meaningful student-centric activities. Three theoretical frameworks guided the study including the work of Baumeister and Leary, Kuh, and Ajzen.
In this mixed method study, quantitative data about affinity, attitude, toward Arizona State University was collected using pre- and post-intervention surveys and qualitative data were gathered through individual semi-structured interviews at the conclusion of the study. Study participants were degree-seeking, undergraduate students whose degree programs were affiliated with the Polytechnic campus. The study was conducted during the first semester for first-year students. The intervention was implemented over a four-week period and consisted of providing information and opportunities to students to initiate connecting to the institution.
Quantitative data exhibited slight upward changes or slight to modest decreases in the dependent variables between pre- and post-intervention assessments. Qualitative data provided a content-rich explanation that helped in understanding the quantitative results. For example, students indicated high behavioral beliefs, attitudes toward involvement, and intentions. Moreover, they demonstrated high levels of connectedness and loyalty to the institution. Discussion focused on describing the complementarity of the data, explaining outcomes relative to the theoretical frameworks, limitations, implications for practice and future research, and lessons learned.
In this mixed method study, quantitative data about affinity, attitude, toward Arizona State University was collected using pre- and post-intervention surveys and qualitative data were gathered through individual semi-structured interviews at the conclusion of the study. Study participants were degree-seeking, undergraduate students whose degree programs were affiliated with the Polytechnic campus. The study was conducted during the first semester for first-year students. The intervention was implemented over a four-week period and consisted of providing information and opportunities to students to initiate connecting to the institution.
Quantitative data exhibited slight upward changes or slight to modest decreases in the dependent variables between pre- and post-intervention assessments. Qualitative data provided a content-rich explanation that helped in understanding the quantitative results. For example, students indicated high behavioral beliefs, attitudes toward involvement, and intentions. Moreover, they demonstrated high levels of connectedness and loyalty to the institution. Discussion focused on describing the complementarity of the data, explaining outcomes relative to the theoretical frameworks, limitations, implications for practice and future research, and lessons learned.
ContributorsMatos, Maria Regina (Author) / Buss, Ray (Thesis advisor) / Krasnow, Aaron (Committee member) / Givans Voller, Julie (Committee member) / Arizona State University (Publisher)
Created2019