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- Creators: Arizona State University
- Creators: Shrake, Scott
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Description
HgCdTe is the dominant material currently in use for infrared (IR) focal-plane-array (FPA) technology. In this dissertation, transmission electron microscopy (TEM) was used for the characterization of epitaxial HgCdTe epilayers and HgCdTe-based devices. The microstructure of CdTe surface passivation layers deposited either by hot-wall epitaxy (HWE) or molecular beam epitaxy (MBE) on HgCdTe heterostructures was evaluated. The as-deposited CdTe passivation layers were polycrystalline and columnar. The CdTe grains were larger and more irregular when deposited by HWE, whereas those deposited by MBE were generally well-textured with mostly vertical grain boundaries. Observations and measurements using several TEM techniques showed that the CdTe/HgCdTe interface became considerably more abrupt after annealing, and the crystallinity of the CdTe layer was also improved. The microstructure and compositional profiles of CdTe(211)B/ZnTe/Si(211) heterostructures grown by MBE was investigated. Many inclined {111}-type stacking faults were present throughout the thin ZnTe layer, terminating near the point of initiation of CdTe growth. A rotation angle of about 3.5° was observed between lattice planes of the Si substrate and the final CdTe epilayer. Lattice parameter measurement and elemental profiles indicated that some local intermixing of Zn and Cd had taken place. The average widths of the ZnTe layer and the (Cd, Zn)Te transition region were found to be roughly 6.5 nm and 3.5 nm, respectively. Initial observations of CdTe(211)B/GaAs(211) heterostructures indicated much reduced defect densities near the vicinity of the substrate and within the CdTe epilayers. HgCdTe epilayers grown on CdTe(211)B/GaAs(211) composite substrate were generally of high quality, despite the presence of precipitates at the HgCdTe/CdTe interface. The microstructure of HgCdSe thin films grown by MBE on ZnTe/Si(112) and GaSb(112) substrates were investigated. The quality of the HgCdSe growth was dependent on the growth temperature and materials flux, independent of the substrate. The materials grown at 100°C were generally of high quality, while those grown at 140°C had {111}-type stacking defects and high dislocation densities. For epitaxial growth of HgCdSe on GaSb substrates, better preparation of the GaSb buffer layer will be essential in order to ensure that high-quality HgCdSe can be grown.
ContributorsZhao, Wenfeng (Author) / Smith, David J. (Thesis advisor) / McCartney, Martha (Committee member) / Carpenter, Ray (Committee member) / Bennett, Peter (Committee member) / Treacy, Michael J. (Committee member) / Arizona State University (Publisher)
Created2011
Description
In a conscious effort to combat the low enrollment of women in construction management, a program was created to retain women through a mentorship program - Advancing Women in Construction. A qualitative analysis, facilitated through a grounded theory approach, sought to understand if the program was indeed successful, and what value did the students derive from the programs and participating in the mentoring process.
ContributorsEicher, Matthew (Author) / Wilkinson, Christine Kajikawa (Thesis advisor) / Calleroz-White, Mistalene (Committee member) / Gibson, Jr., G. Edward (Committee member) / Arizona State University (Publisher)
Created2013
Description
ABTRACT For decades the United States has tried to increase the number of students pursuing science, technology, engineering, and mathematics (STEM) education and careers. Educators and policy makers continue to seek strategies to increase the number of students in the STEM education pipeline. Public institutions of higher education are involved in this effort through education and public outreach (EPO) initiatives. Arizona State University opened its largest research facility, the new Interdisciplinary Science and Technology Building IV (ISTB4) in September, 2012. As the new home of the School of Earth & Space Exploration (SESE), ISTB4 was designed to serve the school's dedication to K-12 education and public outreach. This dissertation presents a menu of ideas for revamping the EPO program for SESE. Utilizing the Delphi method, I was able to clarify which ideas would be most supported, and those that would not, by a variety of important SESE stakeholders. The study revealed that consensus exists in areas related to staffing and expansion of free programming, whereas less consensus exist in the areas of fee-based programs. The following most promising ideas for improving the SESE's EPO effort were identified and will be presented to SESE's incoming director in July, 2013: (a) hire a full-time director, theater manager, and program coordinator; (b) establish a service-learning requirement obligating undergraduate SESE majors to serve as docent support for outreach programs; (c) obligate all EPO operations to advise, assist, and contribute to the development of curricula, activities, and exhibits; (d) perform a market and cost analysis of other informational education venues offering similar programming; (3) establish a schedule of fee-based planetarium and film offerings; and (f) create an ISTB4 centric, fee-based package of programs specifically correlated to K12 education standards that can be delivered as a fieldtrip experience.
ContributorsFisher, Richard D. (Author) / Clark, Christopher M. (Thesis advisor) / Kelley, Michael (Committee member) / Glasper, Rufus (Committee member) / Arizona State University (Publisher)
Created2013
Description
Legislative changes and discussions about the United States falling further and further behind other nations in science, technology, engineering, and math (STEM) achievement are growing. As they grow, STEM instruction in elementary school has earned its place as a national area of interest in education. In the case of Ivory School District, teachers are being asked to radically change their daily practices by consistently implementing inquiry-based STEM experiences in their classrooms. As such, teachers are being asked to scale a divide between the district expectations and their knowledge and experience. Many fourth grade educators are teachers who have been trained as generalists and typically do not have specific background or experience in the philosophy, instructional strategies, or content associated with STEM. Using a prototype approach, this study aims to understand how such teachers conceptualize STEM instruction and the relationship between their experience and conceptions.
ContributorsKenney, Meghan (Author) / Fischman, Gustavo (Thesis advisor) / Powers, Jeanne (Committee member) / Rasch, Katherine D (Committee member) / Arizona State University (Publisher)
Created2013
Description
Historically, African American students have been underrepresented in the fields of science, technology, engineering and mathematics (STEM). If African American students continue to be underrepresented in STEM fields, they will not have access to valuable and high-paying sectors of the economy. Despite the number of African Americans in these fields being disproportionately low, there are still individuals that persist and complete science degrees. The aim of this study was to investigate African American students who excel in science at Arizona State University and examine the barriers and affordances that they encounter on their journey toward graduation. Qualitative research methods were used to address the research question of the study. My methodology included creating a case study to investigate the experiences of eight African American undergraduate college students at Arizona State University. These four male and four female students were excelling sophomores, juniors, or seniors who were majoring in a science field. Two of the males came from lower socioeconomic status (SES) backgrounds, while two of the males were from higher SES backgrounds. The same applied to the four female participants. My research utilized surveys, semistructured interviews, and student observations to collect data that was analyzed and coded to determine common themes and elements that exist between the students. As a result of the data collection opportunities, peer support and financial support were identified as barriers, while, parental support, financial support, peer support, and teacher support were identified as affordances. In analyzing the data, the results indicated that for the student subjects in this study, sex and SES did not have any relationship with the barriers and affordances experienced.
ContributorsBoyce, Quintin (Author) / Scott, Kimberly (Thesis advisor) / Falls, Deanne (Committee member) / Baker, Dale (Committee member) / Arizona State University (Publisher)
Created2012
Description
Latinas and Latinos are currently underrepresented in terms of our 21st century student academic attainment and workforce, compared to the total U.S. Hispanic population. In a field such as mathematical sciences, Hispanic or Latino U.S. citizenship doctoral recipients only accounted for 3.04% in 2009-2010. While there are various initiatives to engage underrepresented STEM populations through education, there is a need to give a voice to the experiences of Latinas and Latinos engaged in such programs. This study explored the experiences of seven Arizona State University undergraduate Latina and Latino Joaquín Bustoz Math-Science Honors Program (JBMSHP) participants as well as examined how the program enhanced their math and science learning experiences. Participants attended either a five-week or eight-week program and ranged in attendance from 2006 to 2011. Students were provided an opportunity to begin university mathematics and science studies before graduating high school. Through a demographic survey and one-on-one guided interview, participants shared their personal journey, their experience in the JBMSHP, and their goals. Using grounded theory, a qualitative research approach, this study focuses on the unique experiences of Latina and Latino participants. Four major themes emerged from the analysis of the data. Each participant applied to the program with a foundation in which they sought to challenge themselves academically through mathematics and/or science. Through their involvement it the JBMSHP, participants recognized benefits during and after the program. All participants recognized the value of these benefits and their participation and praised the program. Overall, the JBMSHP provided the students the resources to grow their academic capital and if they chose seek a STEM related bachelor degree. The results of this study emphasize the need to expand the JBMSHP both within Arizona and nationally. In addition, there is a need to explore the other components of their parent center, the Mathematical, Computational and Modeling Sciences Center (MCMSC), to determine if the suggested pipeline, MCMSC Model for Enhancing the Math and Science Experiences of Latinas and Latinos, can positively impact our 21st century workforce and the dire representational need of Latinas and Latinos in STEM fields.
ContributorsEscontrias, Gabriel (Author) / Turner, Caroline S. (Thesis advisor) / Keller, Gary D. (Committee member) / Calleroz White, Mistalene D. (Committee member) / Arizona State University (Publisher)
Created2012
Description
The goal of this research study was to empirically study a poster-based messaging campaign in comparison to that of a project-based learning approach in assessing the effectiveness of these methods in conveying the scope of biomedical engineering to upper elementary school students. For the purpose of this honors thesis, this research paper specifically reflects and analyzes the first stage of this study, the poster-based messaging campaign. 6th grade students received socially relevant messaging of juniors and seniors at ASU achieving their biomedical aspirations, and received information regarding four crucial themes of biomedical engineering via daily presentations and a website. Their learning was tracked over the course of the weeklong immersion program through a pre/post assessment. This data was then analyzed through the Wilcoxon matched pairs test to determine whether the change in biomedical engineering awareness was statistically significant. It was determined that a poster-based messaging campaign indeed increased awareness of socially relevant themes within biomedical engineering, and provided researchers with tangible ways to revise the study before a second round of implementation. The next stage of the study aims to explain biomedical engineering through engaging activities that stimulate making while emphasizing design-aesthetic appeal and engineering habits of mind such as creativity, teamwork, and communication.
ContributorsSwaminathan, Swetha Anu (Author) / Ganesh, Tirupalavanam (Thesis director) / Shrake, Scott (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Over the past several years, there has been growing concern regarding concussions and traumatic brain injuries (TBIs) in all levels of sports. A concussion is a traumatic brain injury that occurs from a blow to the head. When a concussion occurs, the brain knocks against the walls of the skull. A concussion causes temporary loss of brain function leading to cognitive, physical, and emotional symptoms, such as confusion, vomiting,headache, nausea,depression, disturbed sleep, moodiness, and amnesia. Although the short-term effects of concussions are limited, the long-term effects of concussions, if untreated, can be devastating and even life-threatening. Concussions are having detrimental ramifications on society and it is important to know what these ramifications are. Concussions are a common occurrence in traditional physical sports such as soccer, basketball, and football. However, due to the violent nature of football (American football), concussions are more prevalent and the effects are more severe. Changes to rules and equipment, specifically helmets, have been made to reduce head impacts in football but there is not currently enough evidence to conclude that they significantly lessen the frequency and severity of concussions.
ContributorsLaughlin, Riley James (Author) / Squires, Kyle (Thesis director) / Shrake, Scott (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2015-05
Description
The goal of this research study was to empirically study the effects of a project based learning activity. The effectiveness of this study was benchmarked according to two results: the effectiveness in communicating the scope and impact of engineering, and the effectiveness in increasing interest in computer systems engineering (CSE). This research report presents an analysis of the effects of making engineering education socially relevant, interesting and accessible. High school students participated in a learning experience in which they designed flood evacuation systems that could warn a city of incoming floods. Both pre-assessments and post-assessments were implemented to capture students' awareness of engineering tasks and their interest levels in engineering tasks. Data on students' perceptions of specific engineering tasks were analyzed quantitatively through Wilcoxon signed-rank testing and determined that the program had significant positive effects on developing more accurate conceptions of engineering tasks. The results relating to student interest in CSE indicated that there was an increased level of interest in CSE engineering tasks after the program. There was a 14% increase in number of students who found engineering tasks interesting from 64% to 78%. However, as participants self-selected to participate in this learning experience, many students had positive perceptions of engineering tasks prior to engaging in the learning experience. This study was successful and met both of its primary goals of enhancing awareness and interest in engineering in this particular group of high school students.
ContributorsRidhwaan, Syed (Author) / Ganesh, Tirupalavanam (Thesis director) / Shrake, Scott (Committee member) / Computer Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
While deep disciplinary knowledge will be required to develop next-generation clean energy technologies, the skills to work across disciplines and with diverse stakeholders will also be required. Providing authentic and explicit opportunities for graduate students in science, technology, engineering, and math (STEM) to engage in the broader impacts (BI) 0f their research could support the development of these skills. A concurrent mixed methods action research study was conducted to evaluate the effects of a three-part, semi-structured design workshop on clean energy fellows’ knowledgeability of the broader impacts of their research, their identification with the clean energy field, and their ability to develop high-quality educational outreach products. This study was grounded in a sociocultural theory of learning and informed by several conceptual frameworks: situated learning (Lave & Wenger, 1991), communities of practice (Wenger, 1998), and knowledgeability (Wenger-Trayner & Wenger-Trayner, 2015). Quantitative data was collected through a rubric and survey informed by guiding principles from the Broader Impacts Review Document for National Science Foundation Proposals (Center for Advancing Research Impact in Society, 2020). Qualitative data was collected through this survey and a focus group interview. Results demonstrated a significant, strong, and positive correlation between attendance at the design workshop attendance and Product of Lasting Value (PLV) quality. Unfortunately, the lack of respondents in the post-survey prevented the ability to quantify any changes that took place in fellows’ knowledgeability of the BI of their research and their identification with the clean energy field due to the innovation. Yet, results from the focus group interview do show that some fellows experienced increased knowledgeability of the BI of their research and identification with the clean energy field, but these gains were not necessarily due to the PLV Design Workshop.
ContributorsHendrickson, Danica Lyn (Author) / Salik, Steven (Thesis advisor) / Weinberg, Andrea (Committee member) / Garcia, David (Committee member) / Arizona State University (Publisher)
Created2022