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The purpose of this study was to determine the impact of Virginia school divisions’ policy of paying the fee for students to take Advanced Placement exams on Advanced Placement course enrollment, the number of Advanced Placement exams taken by students, the average scores earned and the percent of students earning qualifying scores of 3, 4, or 5 on Advanced Placement exams. The hierarchical regression models utilized Advanced Placement scores and school demographic data provided by the Virginia Department of Education combined with survey data on Advanced Placement policies and the number years that exam fees had been paid collected from school principals, directors of counseling and division officials. School level demographics considered in the analyses included school size, socioeconomic status, ethnicity and school achievement. Advanced Placement enrollment and the number of exams taken increased significantly over the period of study while the average scores and number of qualifying scores earned by Virginia students remained unchanged. The payment of exam fees by Virginia school divisions had no impact on the change in Advanced Placement participation. Average scores and percent of qualifying scores earned on Advanced Placement science exams fell over the study period, though participation grew in line with the overall Advanced Placement participation. No significant differences in the change in Advanced Placement participation or scores were observed based on the underserved minority enrollment of schools, however both enrollment, average scores and qualifying scores on Advanced Placement exams fell significantly as the percent of students qualified that for free and reduced-lunch programs at a school increased.

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This thesis describes the study of a variety of nanoscale materials and the development of novel synthetic strategies for their production. While the focus and bulk of this study have been directed specifically at subwavelength lithography, a significant portion of this thesis research involves nanoparticle synthesis, characterization, and functionalization. Put in very simple terms, optical lithography is a process where a beam of light, focused in a specific pattern, is used to generate a physical pattern on a solid substrate. This technology forms the basis for almost all microchip production in the world at the present time. As demand for faster and more powerful chips increases, the need to further miniaturize the patterns while minimizing cost has become very important. Multiple photochemical systems were developed in the search for non-reciprocal photochemistry at 193 nm to increase the resolution of lithographic processes at that wavelength. One approach, based on anthracene sensitization of sulfonium salts for acid generation, used photochemically reversible 4+4 aromatic cycloaddition reactions to introduce the non-linear photochemistry. A second approach took advantage of the photochemistry of N-methylphenothiazine and provided the first true example of a lithographically-relevant multi-photon acid generating process. Since all of the systems we studied used sulfonium salts as the acid generating species, we also looked at the photochemistry of the salts themselves. We evaluated the structural effects of the salts on their direct photochemistry and the implications for sensitized multi-photon photochemistry. We found that the identity of the anion plays a significant role in both processes and propose a new photochemical mechanism for acid generation that involves a charge transfer excitation process. We also describe the synthesis and characterization of novel fluorescent silver nanoparticles, both in solution and polymer films. We show that the fluorescent images can be patterned easily and preliminary results show that photolithography based on nanoparticle formation may be possible. This latter approach could provide a facile route to nanoparticle-embedded functional materials. This work with nanoparticles was inspired partly by earlier work, also presented herein, on semiconductor nanoparticles and their interactions with disulfide ligands.

This thesis describes the study of a variety of nanoscale materials and the development of novel synthetic strategies for their production. While the focus and bulk of this study have been directed specifically at subwavelength lithography, a significant portion of this thesis research involves nanoparticle synthesis, characterization, and functionalization. Put in very simple terms, optical lithography is a process where a beam of light, focused in a specific pattern, is used to generate a physical pattern on a solid substrate. This technology forms the basis for almost all microchip production in the world at the present time. As demand for faster and more powerful chips increases, the need to further miniaturize the patterns while minimizing cost has become very important. Multiple photochemical systems were developed in the search for non-reciprocal photochemistry at 193 nm to increase the resolution of lithographic processes at that wavelength. One approach, based on anthracene sensitization of sulfonium salts for acid generation, used photochemically reversible 4+4 aromatic cycloaddition reactions to introduce the non-linear photochemistry. A second approach took advantage of the photochemistry of N-methylphenothiazine and provided the first true example of a lithographically-relevant multi-photon acid generating process. Since all of the systems we studied used sulfonium salts as the acid generating species, we also looked at the photochemistry of the salts themselves. We evaluated the structural effects of the salts on their direct photochemistry and the implications for sensitized multi-photon photochemistry. We found that the identity of the anion plays a significant role in both processes and propose a new photochemical mechanism for acid generation that involves a charge transfer excitation process. We also describe the synthesis and characterization of novel fluorescent silver nanoparticles, both in solution and polymer films. We show that the fluorescent images can be patterned easily and preliminary results show that photolithography based on nanoparticle formation may be possible. This latter approach could provide a facile route to nanoparticle-embedded functional materials. This work with nanoparticles was inspired partly by earlier work, also presented herein, on semiconductor nanoparticles and their interactions with disulfide ligands.

Labyrinth seals are widely used in various turbo machines including turbines, compressors and pumps. Their purpose is to prevent the backflow of the working fluid. This backflow is due to the leakage of the seal. This loss affects the efficiency of the turbo machine, so it becomes critically important to assess the leakage of the seals under the given operating conditions. The accuracy of prediction of leakage is also important for performing rotodynamic analysis. The geometric shape of the seal plays an important role in influencing the fluid flowing through the seals and the leakage rate. Many empirical seal leakage prediction models, useful from a design/analysis point of view, have been developed. Saikishan Suryanarayanan and Gerald. L .Morrison studied the influence of various geometric and flow parameters on the leakage of labyrinth seals with rectangular cavities. They proposed a leakage equation based on their Computational Fluid Dynamics (CFD) simulations using software FLUENT. However, many real world labyrinth seals do not have simple rectangular cavities. In particular, this thesis focuses on seals with Isosceles triangle shaped teeth, right triangle shaped teeth, and a NASA seal. In the present work, CFD simulations of labyrinth seals with advanced cavity shapes are performed and the results are compared with the predictions of the rectangular seal model. The results show that the advanced cavities like, Isosceles shaped seal were more efficient as compared to rectangular seals. The pressure drop, which was taken as one of the key parameters to adjudge the efficiency of seals showed negative behavior in some of the advanced cavity shaped seal. The advanced cavity shaped seals are used in various turbo machinery equipments like steam and gas turbines. This study shows that Isosceles cavity shaped seals are the most efficient among all the advanced cavity shapes used in the present study.

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Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1931. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed January 19, 2010) Includes bibliographical references (p. 81-83) and index (leaves 98-102).

This thesis begins with the simple observation that the term ‘green consumption’ would have appeared, at the very least, oxymoronic to those concerned with environmental issues some thirty years ago. Yet now it is a commonplace aspect of popular, academic and policy discourse in the global north. In recognizing the diversity of products and services that fall under the rubric of ‘green consumption,’ this project situates it as a form of discursive positioning and a potential set of a practices that indicate a ‘friendly’ or benign association between consumption and the environment. The thesis has three components. Firstly, it reviews the literature on consumer culture and environmentalism, highlighting relevant thematic debates concerning the critique of consumer culture and its potential effects upon the environment. Secondly, the thesis constructs a post-Foucauldian ‘analytics of green consumption’ in order to understand such a radical shift in representations of consumption and environmental thinking. Thirdly, the thesis employs this analytics to examine two dominant ‘environmentalities’ or programmes of green consumption – Eco Labelling and the Ecological Footprint – wherein the advanced liberal rhetorics of ‘choice,’ ‘freedom’ and ‘responsibility’ are found to operate in different ways. Drawing upon the work of Rose (1999), Barry et al. (1996) and others, the thesis shows how these ‘informational’ techniques are predicated upon and reproduce specific conceptions of consumer behaviour, encouraging the formation of ‘green consumer-subjects.’ It is argued that the terrain of consumption has become the primary locus where political, social, economic and cultural elements overlap to shape the decisions of consumers. The field of consumption is being restructured around lifestyle choice-driven models of responsible subjectivity, with consumption becoming the key means for shaping the conduct of individual citizens. The thesis goes on to argue that such a market-based approach to engendering green consumption is problematic in terms of its conception of how consumer choice and freedom are constrained, raising difficult issues for policy efforts in this area. The thesis also points toward the limits of post-Foucauldian analyses of green consumption, especially the impossibility of knowing whether, and for what reasons, practices of green consumption are taken up by consumers. / Thesis (Master, Sociology) -- Queen's University, 2009-09-25 08:48:47.876