Compositionally Graded Indium Gallium Nitride Solar Cells

For the past several decades, methods to harvest solar energy have been investigated intensively. A majority of the work done in this field has been on solar cells made with silicon – the most mature semiconductor material. Recent developments in material fabrication and processing techniques have enabled other semiconductor materials to attract practical interest and research effort as well. Indium gallium nitride (InGaN) is one such material. The material properties of InGaN indicate that solar cells made with it have the potential to achieve much higher power density than a standard silicon solar cell. High power density InGaN solar cells could replace silicon cells in applications where size and weight are critical, or in environments where silicon devices cannot survive. This is especially true of space, and most InGaN development has been done with that in mind. However, at high enough power densities, InGaN solar cells could begin to compete with silicon devices in commercial applications. The goal of this research is to investigate the effect a novel growth technique for InGaN – graded layer deposition – has on the power density of an InGaN solar cell. In this research, first a baseline InGaN solar cell was grown, fabricated, and characterized. A standard PiN (P: p-type, i: intrinsic, N: n-type) structure was used for this baseline device. The reference alloy composition was chosen to be 20% indium and 80% gallium (In­0.2Ga0.8N). This sample was grown using molecular beam epitaxy (MBE) under standard conditions for the material. Once the reference crystal was fabricated it was optically and electrically characterized. The material composition was verified through a combination of x-ray diffraction (XRD), photoluminescence (PL), and transmittance/reflectance measurements. The quality of the surface of the crystal was examined using atomic force microscopy (AFM). Once the optical characterization of the material was complete, the crystal was processed for electrical characterization. Individual devices were constructed by etching away much of the p-type and intrinsic layer, leaving behind circular mesas. Each mesa was then given a top and bottom contact, so that it could be connected to test equipment electrically. After the crystal was processed into a solar cell in this way, each device was connected to a test source electrically, and the current-voltage (I-V) curves were taken. This information was used to find the current and power densities of each device. The second step in this work was fabricating and characterizing a graded layer device that was similar to the reference cell. To this end, the graded layer device was chosen to have a starting composition of 25% indium and 75% gallium, with an ending composition of 15% indium and 85% gallium in place of the intrinsic layer. This new crystal was grown under identical conditions as the baseline cell, except for the graded layer, which required a slightly different approach. The graded layer crystal was then characterized and processed consistent with the reference in an attempt to get as accurate of a comparison between the two as possible. The results of this research could significantly affect the field of III-nitride solar cells

Sakura, Sakura | 16-96870

Sakura, Sakura Part Number: 16-96870 Price: $1.75 Voicing: SA Music By: Japanese Folk Song Arranged By: Christopher Matthews Translation: Cherry Blossoms, Cherry Blossoms. On mountains, in villages. As far as you can see. They look like fog or clouds. They are fragrant in the morning sun. Cherry Blossoms, Cherry Blossoms. In full bloom. Watch a Video!https://digitalcommons.butler.edu/jca_scores/1300/thumbnail.jp

The meaning of concrete for inter-war Nottingham: geography, economy and politics

What did concrete mean to the city of Nottingham during the 1920s and 1930s? How did the city respond to the formative years of this material in terms of geography, economy and politics? On the one hand this was a city that momentarily saw concrete as the vanguard of pragmatic modernism and economic diversification alongside a utilitarian approach to social reform. And on the other, a city more willing to fall back on established materials and structures. Concrete was very rarely a monstrosity for inter-war Nottingham: it more often meant economic revitalisation, technological change, social improvement, cleanliness, efficiency, fashion and comfort. As a product of the landscape, the city made an important contribution to the formative years of this twentieth-century material. In a climate of recession after the First World War, concrete represented a hope for the future that was readily expressed by the most innovative of the city's commercial firms. Yet compared to the city's commercial concrete achievements, the approach from local government appeared tame: here a delicate balance had to be played out between the power of conservative symbolism and the efficiency of social improvement

The Creative Impulse

Panel: The Creative Impulse (this panel took place in St. Louis

The thrill of the fight - sensuous experiences of boxing - towards a sociology of violence

This thesis employs ethnographic methods to examine lived experiences of sports violence, particularly, the ways in which action in, and around, a boxing ring can be psychologically and physically significant. Crucial in this regard is the social conditioning of such experiences. Here, norms and values that dominate the framing of sports violence are informed by participants assumptions based on traditional understandings of gender and class. In this way, social processes associated with masculine identities and the working classes inform what was considered possible, permissible and pleasurable. It is contended that phenomenologically informed accounts of such pleasurable experiences of violence remain relatively underrepresented within research examining sports participation. The central focus of this thesis is to provide such an account within a boxing environment. As such, the observations and interviews presented in what follows contribute to the sociological study of sports violence in particular and violence more generally. Alongside this substantive dimension, there are also conceptual, theoretical and methodological contributions that can inform future sociological study in the area and more broadly. Specifically, the contention that experiences of sports violence tend to contain a mimetic dimension and a figurational or processes sociological interpretation of such experiences, are empirically evaluated. The naturalisation of biological interpretations of masculinity as a popular means of explaining and justifying acts of violence is explored. The embodiment of social processes, including masculinity, is theorised using figurational sociology, specifically employing the interconnected concepts of habitus, figuration and established/outsider relations. Methodologically, notions of insider / outsider knowledge are reconceptualised using Elias discussions of involvement/detachment. The sports violence masculinity complex is proposed as a means of conceptually framing the social processes that contour the pleasurable experiences of conducting, and being the target of, violence. This overarching frame is linked to local factors that also impinge upon the gym space. With these social fault lines explored, a phenomenologically sensitive account of sports violence is presented. In this way, it is hoped that some of the theoretical pitfalls of other, arguably asociological, examinations of emotion and sensation are avoided. Using field notes and interview extracts a wart and all picture of gym life is painted. Particular attention is paid to sensuous experiences of working the bag and sparring. Here, significant physical markers and emotional expressions are detailed. Inside and around the ring, men learned the techniques and tactics of mimetic violence. These experiences enabled a socially conditioned, controlled decontrolling of emotional controls and the elicitation of physical sensations that generally remain off limits during the relative emotional and physical staleness of their work-a-day lives. It is contended that the experiences detailed within this thesis and the theoretical frame used to interpret them can inform future work examining sports violence and violence more generally

EZRA pound and the ideogrammic method

This work addresses the question of Pound's poetics, proceeding upon the conviction that the term "ideogrammic method", so often slighted by commentators, is to be taken seriously, and that an understanding of its nature and implications provides a sound framework for one's understanding of Pound's mature poetic practice. Part One begins by tracing the evolution of Imagism/Worticism, locating in Pound's theory and practice at that time his first adumbration of the poetic morphology which I maintain is central to the Cantos. The first four Cantos are then examined and their pattern of theophanies related to the merphology. The Malatesta Cantos are identified as the first expression of the ideogrammic method, the latter being defined as an extention into the "epic" dimension of Imagist/Vorticist principles. Part Two retreats somewhat from the detail of the Cantos to deal more speculatively with the ideogrammic method and its related ideas. In particular, through the figures of Francis Bacon, Emerson, Fenollosa and Pound himself the method is set in relation to the Adamic conception of language. Part Three begins by further enlarging the terms of the ideogrammic method to incorporate Pound's notion of the forma, and relating both method and notion to the poetic morphology. This complex of ideas is then shown in action in Cantos XXXIX and XLVII. The rhythms of the Leopoldine Cantos are examined, and a more generalizing discussion of rhythms in the Cantos as a whole follows; This is then related to the question of form in the poem. The work concludes with a detailed examination of the Pisan Cantos and Canto XC. The ideogrammic method is not a body of settled doctrine, but I believe it to be the generative locus of Pound's mature poetics. It as as such that I would recommend the concept for fresh attention

Effective Principal Leadership Behaviors and AYP Attainment: An Examination of Distinguished and Needs Improvement Middle Schools in Georgia

The purpose of this study was to examine effective principal leadership behaviors in relation to the AYP attainment of middle schools in Georgia. The relationship was examined through analyses of teachers\u27 ratings of principals\u27 leadership behaviors via an e-mailed instrument. The instrument contained 32 specific leadership behaviors linked to the 11 Marzano et al.\u27s leadership responsibilities with the highest correlation to student achievement. Three major research questions guided the inquiry of the study. First, the study investigated the presence of the leadership behaviors in distinguished and needs improvement middle schools in Georgia. Secondly, the study investigated whether there were differences between principal leadership behaviors in distinguished and needs improvement middle schools in Georgia. Lastly, the study investigated whether the 11 leadership behaviors were related to and predictive of AYP status in Georgia middle schools. Descriptive statistics indicated that the mean ratings of teachers in distinguished middle schools were higher than the mean ratings of teachers in needs improvement schools for 10 of the 11 leadership responsibilities. Results of t-Test analyses indicated that teachers in distinguished middle schools had statistically higher ratings than teachers in needs improvement middle for the leadership responsibilities: order, resources, input, and change agent. Multiple Regression analyses were employed and revealed that the leadership responsibility, order, was positively related to and predictive of AYP status. The leadership responsibilities, flexibility and culture, as well the school variables, the size of the school, percentage of students in the school with disabilities, and percentage of students in the school receiving free and reduced lunch were all negatively related to and predictive of AYP status