Matching Items (99)
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Earth-abundant sustainable inorganic thin-film solar cells, independent of precious elements, pivot on a marginal material phase space targeting specific compounds. Advanced materials characterization efforts are necessary to expose the roles of microstructure, chemistry, and interfaces. Herein, the earth-abundant solar cell device, Cu2ZnSnS(4-x)Sex, is reported, which shows a high abundance of

Earth-abundant sustainable inorganic thin-film solar cells, independent of precious elements, pivot on a marginal material phase space targeting specific compounds. Advanced materials characterization efforts are necessary to expose the roles of microstructure, chemistry, and interfaces. Herein, the earth-abundant solar cell device, Cu2ZnSnS(4-x)Sex, is reported, which shows a high abundance of secondary phases compared to similarly grown Cu2ZnSnSe4.

ContributorsAguiar, Jeffery A. (Author) / Patel, Maulik (Author) / Aoki, Toshihiro (Author) / Wozny, Sarah (Author) / Al-Jassim, Mowafak (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2016-02-02
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The development of high efficiency III-V solar cells is needed to meet the demands of a promising renewable energy source. Intermediate band solar cells (IBSCs) using semiconductor quantum dots (QDs) have been proposed to exceed the Shockley-Queisser efficiency limit [1]. The introduction of an IB in the forbidden gap of

The development of high efficiency III-V solar cells is needed to meet the demands of a promising renewable energy source. Intermediate band solar cells (IBSCs) using semiconductor quantum dots (QDs) have been proposed to exceed the Shockley-Queisser efficiency limit [1]. The introduction of an IB in the forbidden gap of host material generates two additional carrier transitions for sub-bandgap photon absorption, leading to increased photocurrent of IBSCs while simultaneously allowing an open-circuit voltage of the highest band gap. To realize a high efficiency IBSC, QD structures should have high crystal quality and optimized electronic properties. This dissertation focuses on the investigation and optimization of the structural and optical properties of InAs/GaAsSb QDs and the development of InAs/GaAsSb QD-based IBSCs.

In the present dissertation, the interband optical transition and carrier lifetime of InAs/GaAsSb QDs with different silicon delta-doping densities have been first studied by time-integrated and time-resolved photoluminescence (PL). It is found that an optimized silicon delta-doping density in the QDs enables to fill the QD electronic states with electrons for sub-bandgap photon absorption and to improve carrier lifetime of the QDs.

After that, the crystal quality and QD morphology of single- and multi-stack InAs/GaAsSb QDs with different Sb compositions have been investigated by transmission electron microscopy (TEM) and x-ray diffraction (XRD). The TEM studies reveal that QD morphology of single-stack QDs is affected by Sb composition due to strain reducing effect of Sb incorporation. The XRD studies confirm that the increase of Sb composition increases the lattice mismatch between GaAs matrix and GaAsSb spacers, resulting in increase of the strain relaxation in GaAsSb of the multi-stack QDs. Furthermore, the increase of Sb composition causes a PL redshift and increases carrier lifetime of QDs.

Finally, the spacer layer thickness of multi-stack InAs/GaAsSb QDs is optimized for the growth of InAs/GaAsSb QD solar cells (QDSCs). The InAs/GaAsSb QDSCs with GaP strain compensating layer are grown and their device performances are characterized. The increase of GaP coverage is beneficial to improve the conversion efficiency of the QDSCs. However, the conversion efficiency is reduced when using a relatively large GaP coverage.
ContributorsKim, Yeongho (Author) / Honsberg, Christiana (Thesis advisor) / Goodnick, Stephen (Committee member) / Faleev, Nikolai (Committee member) / Smith, David (Committee member) / Arizona State University (Publisher)
Created2015
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The literature including social media shows that Mexican/Latino immigrants have attracted contempt and have been traditionally objected to as a minority in the U.S. The intent here is to search for historical and other factors that might explain the public antipathy and to identify reasons that could, either in isolation

The literature including social media shows that Mexican/Latino immigrants have attracted contempt and have been traditionally objected to as a minority in the U.S. The intent here is to search for historical and other factors that might explain the public antipathy and to identify reasons that could, either in isolation or in combination with others, explain anti-immigrant sentiments among people, many of whom are descendants of immigrants. The perusal of the challenges of Mexican immigrants to the U.S. through the decades will highlight some similarities related to discrimination against waves “peoples of color”, not only in the U.S. but in other parts of the world. The daily treatment within the society of immigrants of color as well as the frequent lower immigration quotas imposed on certain groups, including Mediterranean people, makes the topic quite relevant to today’s concerns.

Created2017-06
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This article presents an exploration of the relationship between community building and lifelong learning. Using a reflective style, the authors propose that the fusion of community building principles with lifelong learning practice can positively transform educational practice. Seven positive pursuits are highlighted regarding their potential to assist the implementation of

This article presents an exploration of the relationship between community building and lifelong learning. Using a reflective style, the authors propose that the fusion of community building principles with lifelong learning practice can positively transform educational practice. Seven positive pursuits are highlighted regarding their potential to assist the implementation of community building into lifelong learning programs: (1) asset-based thinking; (2) critical reflection; (3) systems thinking; (4) cognitive vibrancy, (5) inclusiveness; (6) creative expression; and, (7) purpose in life. These pursuits draw upon the power of the community development field to bring about more positive transformative moments for individuals and communities participating in lifelong learning programs. The metaphor of bread making is used to illustrate how such transformative moments occur and why they are meaningful to individuals pursuing lifelong learning.

Created2017
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The increased interdependence and complexity of modern societies have increased the need to involve all members of a community into solving problems. In times of great uncertainty, when communities face threats of different kinds and magnitudes, the traditional top-down approach where government provides solely for community wellbeing is no longer

The increased interdependence and complexity of modern societies have increased the need to involve all members of a community into solving problems. In times of great uncertainty, when communities face threats of different kinds and magnitudes, the traditional top-down approach where government provides solely for community wellbeing is no longer plausible. Crowdsourcing has emerged as an effective means of empowering communities with the potential to engage individuals in innovation, self-organization activities, informal learning, mutual support, and political action that can all lead to resilience. However, there remains limited resource on the topic. In this paper, we outline the various forms of crowdsourcing, economic and community resilience, crowdsourcing and economic resilience, and a case study of the Nepal earthquake. his article presents an exploratory perspective on the link can be found between crowdsourcing and economic resilience. It introduces and describes a framework that can be used to study the impact of crowdsourcing initiatives for economic resilience by future research. An initial a set of indicators to be used to measure the change in the level of resilience is presented.

ContributorsSmith, Kendra (Author) / Ramos, Isabel (Author) / Desouza, Kevin (Author) / College of Public Service and Community Solutions (Contributor)
Created2015-09
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Identifying stakeholder beliefs and attitudes is critical for resolving management conflicts. Debate over outdoor cat management is often described as a conflict between two groups, environmental advocates and animal welfare advocates, but little is known about the variables predicting differences among these critical stakeholder groups. We administered a mail survey

Identifying stakeholder beliefs and attitudes is critical for resolving management conflicts. Debate over outdoor cat management is often described as a conflict between two groups, environmental advocates and animal welfare advocates, but little is known about the variables predicting differences among these critical stakeholder groups. We administered a mail survey to randomly selected stakeholders representing both of these groups (n = 1,596) in Florida, where contention over the management of outdoor cats has been widespread. We used a structural equation model to evaluate stakeholder intention to support non-lethal management. The cognitive hierarchy model predicted that values influenced beliefs, which predicted general and specific attitudes, which in turn, influenced behavioral intentions. We posited that specific attitudes would mediate the effect of general attitudes, beliefs, and values on management support. Model fit statistics suggested that the final model fit the data well (CFI = 0.94, RMSEA = 0.062). The final model explained 74% of the variance in management support, and positive attitudes toward lethal management (humaneness) had the largest direct effect on management support. Specific attitudes toward lethal management and general attitudes toward outdoor cats mediated the relationship between positive (p<0.05) and negative cat-related impact beliefs (p<0.05) and support for management. These results supported the specificity hypothesis and the use of the cognitive hierarchy to assess stakeholder intention to support non-lethal cat management. Our findings suggest that stakeholders can simultaneously perceive both positive and negative beliefs about outdoor cats, which influence attitudes toward and support for non-lethal management.

Created2014-04-15
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Many municipal governments have adopted affordable housing policies to benefit people whose socio-economic status is not commensurate with the price of housing. However, the effects and the functions of these policies in the city on sustainable development and living remains limited. Using a comparative case study, this study explores the

Many municipal governments have adopted affordable housing policies to benefit people whose socio-economic status is not commensurate with the price of housing. However, the effects and the functions of these policies in the city on sustainable development and living remains limited. Using a comparative case study, this study explores the characteristics and effects of affordable housing policies in three metropolitan cities in China: Beijing, Tianjin, and Guangshou. This study finds that these cities have their unique affordable housing policies and have experienced various challenges in implementing those policies. Conclusions and implications for other cities in China are addressed.

ContributorsCai, Xiang (Author) / Tsai, Chin-Chang (Author) / Wu, Wei-Ning (Author) / College of Public Service and Community Solutions (Contributor)
Created2017-04-01
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The purpose of this research project was to implement a staff development program that would assess and strengthen the level of emotional intelligence of the teachers at a local low-income middle school. A goal of the project was to increase a teacher's level of emotional intelligence such that they could

The purpose of this research project was to implement a staff development program that would assess and strengthen the level of emotional intelligence of the teachers at a local low-income middle school. A goal of the project was to increase a teacher's level of emotional intelligence such that they could strengthen effective relationships and better ground them in trust with their students. Teachers participated in a 9 week program. Pre- and post emotional intelligence scores were reported.
ContributorsCarpenter, Breanna (Author) / Lietz, Cynthia (Thesis director) / Ferguson, Kristin (Committee member) / Rittenhouse, Sarah (Committee member) / School of Social Work (Contributor) / College of Public Service and Community Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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The rates of anxiety, depression, and attempted suicide for transgender individuals are extremely elevated relative to the general population. Yet, little research has been conducted about the transgender population regarding social transition (an individual presenting as their authentic/true gender, one different than the gender they were assigned at birth, in

The rates of anxiety, depression, and attempted suicide for transgender individuals are extremely elevated relative to the general population. Yet, little research has been conducted about the transgender population regarding social transition (an individual presenting as their authentic/true gender, one different than the gender they were assigned at birth, in the context of everyday life) and parental acceptance. Both of which have been shown to impact the mental health of transgender individuals. The purposes of this study were: (1) To characterize a sample of transgender adults on their age of awareness of their authentic gender identity and their age of social transition. (2) Examine whether age of social transition, (3) parental acceptance, and (4) the gap in time between age of awareness and age of social transition (awareness-transition gap) were related to mental health. (5) Examine whether parental acceptance was related to age of social transition or to awareness-transition gap. (6) Examine whether age of social transition or awareness-transition gap interact with parental acceptance as correlates of mental health. The sample consisted of 115 transgender adults, ages 18 to 64. Measures were separated into 7 subheadings: demographics, transgender
on-cisgender identity, age of awareness, age of social transition, primary caregiver acceptance, secondary caregiver acceptance, and mental health. Hypotheses were partially supported for age of social transition with mental health, parental acceptance with mental health, and awareness-transition gap with parental acceptance. This study investigated under studied concepts of social transition and parental acceptance that appear to have an effect on the mental health of transgender adults.
ContributorsRosenberg, Beth Ann (Author) / Gonzales, Nancy (Thesis director) / Saenz, Delia (Committee member) / Davis, Mary (Committee member) / Department of Psychology (Contributor) / Sanford School of Social and Family Dynamics (Contributor) / College of Public Service and Community Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05