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The More-electric aircraft (MEA) concept has been raised since 1990s in order to increase fuel economy and reduce environmental impact of aircrafts. The fundamental of the concept is to replace pneumatic, hydraulic and mechanical systems in conventional aircrafts with its electrical equivalent that is lighter and more reliable. In this movement, power electronics technology plays a key role in interfacing the new types of electrical loads to the new aircraft electrical power system. One of the major tasks for power electronics circuits in MEA is to transfer aircraft variable frequency AC voltage into DC voltage, which could be conveniently utilized by different types of loads or power buses. The converters carrying out the task is commonly known as "rectifiers". This work aims at designing and constructing rectifiers that can work efficiently and reliably in more-electric aircrafts. One of the major challenge for these rectifiers comes from the complex aircraft environment. The ambient temperature could be as high as 70 ºC. Moreover, active cooling for converters may not be desirable. To deal with this, rectifiers should achieve extreme efficiency (especially at full load) so that all the components are not overheated without active cooling. This work aims at achieving extreme converter efficiency through advanced converter topologies and design. Both single-phase and three-phase rectifiers are discussed in this work. For single-phase rectifiers, this work focused on boost-type power factor correction (PFC) converters due to the promising efficiency and good PFC characteristics. The well-known two-level semi-bridgeless PFC boost rectifier, together with its interleaved and three-level counterparts, are studied and compared in this work. The operation principles of the converters are analyzed. Models and methods for converter efficiency evaluation are discussed. The efficiency evaluation of the topologies shows the advantage of three-level topologies and interleaved topologies in achieving higher efficiency and better thermal management. For three-phase rectifiers, two-level boost rectifier, three-level neutral point clamped (NPC) rectifier and Vienna rectifier are investigated. The evaluation shows the advantage of Vienna rectifier in achieving high efficiency due to reduced switching loss. Based on the evaluation of single-phase and three-phase active rectifiers, the author selected interleaved Vienna rectifier to achieve extreme efficiency and avoid overheating problem. The operation principle of the interleaved Vienna rectifier is introduced, with particular attention paid to the circulating current generated by interleaving operation. The design procedure for achieving maximum efficiency is described. Finally, a prototype of the proposed converter is constructed, which achieves 99.26% efficiency at nominal load. / Master of Science

Deeply influenced by emotional, ethical, and ecological principles, John Steinbeck developed a holistic ideology to describe and analyze the relationships among individuals, society, and the more-than-human world. Although he explored environmental issues with ecological insight and philosophical contemplation that placed him well beyond his literary and scientific contemporaries, Steinbeck’s contributions to modern ecological inquiry and environmental thought have received only intermittent attention from literary scholars. Throughout his writing, Steinbeck develops a view of intellectual holism that encourages (perhaps even enables) us to dovetail science and ethics as we attempt to construct a new environmental paradigm. Viewing the world through his holistic lens, Steinbeck was able to see the global ecosystem, local environments, human communities, and even minute tide pools as objects of scientific and artistic inquiry. Specifically, it is my contention that the American environmental movement owes a greater debt to John Steinbeck than it realizes. In short, John Steinbeck made significant contributions to the growing awareness of human-nature interconnectedness and the parallels between social ills and ecological ailments. Yet, for whatever reasons Steinbeck is not granted a position of honor alongside the other giants of American environmental thought. Now witnessing the full blossoming of 21st century environmentalism, it is useful to cast a reflexive eye upon our ideological forebears with the intent to better understand the genealogy of the American environmental movement. Doing so will not only provide a richer and fuller family tree, but will also promote additional flourishing of new approaches to solving ongoing environmental troubles. / Master of Arts

The United States Air Force is in the process of developing a more electric aircraft. The development of an aircraft Integrated Power Unit and an Internal Starter/Generator will be instrumental in producing sufficient electrical power to run all non propulsive systems. Iron-cobalt alloys, such as Hiperco alloy 50HS, are high temperature, high strength magnetic materials ideal for these power applications. Design requirements and previous studies indicate that these materials need to survive in temperatures up to 1000F (810K), rotation speeds of about 55,000 rpm, and have strengths in excess of 80 ksi. Research conducted by Fingers provided the material and creep properties used in the analysis presented in this report. The finite element method was used to analyze a spinning rotor mounted to a circular shaft via an interference fit subjected to various operating environments. The power law creep model defined by Fingers was used to analyze three distinct rotor configurations. The first configuration was a constant temperature single lamina, mounted to a shaft of equal thickness, subject to temperatures between 727K and 780K, rotation speeds between 35,000 rpm and 60,000 rpm, and two different interference fits: 0.0015 inches and 0.003 inches. The results yield conservative predictions that indicate that these models could not survive the required operating conditions. The second configuration was a linear radial variation in temperature single lamina, mounted to a shaft of equal thickness, subjected to three temperature ranges, rotation speeds between 30,000 rpm and 55,000 rpm, and two different interference fits; 0.0015 inches and 0.003 inches. These results represent a more realistic model, which indicate that the "cooler" inner portions of the rotor restrict the creep deformations of the "hotter" outer portions resulting in higher possible operating temperatures and rotation speeds very near the required operating conditions. The third configuration was a lamina stack comprised of two rotor lamina, with a Coulomb friction surface interaction, and held together by a compressive axial force. These models represent a first step towards understanding the behavior of the entire rotor stack. / Master of Science

Made available in DSpace on 2016-04-28T18:23:20Z (GMT). No. of bitstreams: 1 Denise Lage Maggioli.pdf: 29496152 bytes, checksum: d58aba37e35ff1739460c8a9b535fa32 (MD5) Previous issue date: 2007-02-13 / This research is a result of the concerns I had as a professional in education related to the evaluation of didactic material, which nowadays include not only printed material but also material connected to technology, such as softwares and online courses. This research aims at evaluating an educational software recommended to be used at the public schools of Ensino Fundamental e Médio, considering the paradigms presented in the Parâmetros Curriculares Nacionais Língua Estrangeira. The theoretical basis for this research were the Parâmetros Curriculares Nacionais -Lingua Estrangeira (Brasil, 1998) and Parâmetros Curriculares Nacionais Ensino Médio (Brasil, 1999), used as a reference by the teacher in his or her classroom, the lines of thinking in psychology that were used as basis for the teaching and learning theories that have had most influence in the teaching and learning process of foreign language in our culture (Williams & Burden, 1997; Rego, 2004; Vygotsky, 1993,2003), the language description theories (Graddol, 1994; Hutchinson & Waters 1987; Bloor & Bloor, 1995), considerations on didactic material (Cunningsworth, 1984, 1995; Tomlinson, 1998; Graves, 2000), the definition of task according to Ellis (2003), software evaluation criteria (Squires & McDougall, 1997; Stirling, 1998; Alagumali & Anderson, 1997) and the evaluation criteria for didactic material by Ramos (1998) and Freire et al. (2004). This research has shown that, although the language description theories and the teaching and learning theories that constitute the software do not match the educational paradigms in force nowadays, according to the Parâmetros Curriculares Nacionais Língua Estrangeira (Brasil, 1998) and the Parâmetros Curriculares Nacionais Ensino Médio (Brasil, 1999), from a technological point of view the software presents resources that can help both teachers and students in the teaching and learning process of a foreign language / Esta pesquisa originou-se de uma inquietação minha como profissional da área de educação com respeito à avaliação de material didático, que hoje além de material impresso inclui também materiais ligados à área tecnológica, tais como softwares e cursos on-line. O objetivo deste trabalho é avaliar um software educacional (Tell Me More), recomendado para ser usado na rede pública de Ensino Fundamental e Médio à luz dos paradigmas educacionais apregoados nos Parâmetros Curriculares Nacionais Língua Estrangeira. As bases teóricas desta pesquisa foram os Parâmetros Curriculares Nacionais -Língua Estrangeira (Brasil, 1998) e Parâmetros Curriculares Nacionais Ensino Médio (Brasil, 1999), utilizados como referência para o trabalho do professor em sala de aula, as correntes de pensamento da psicologia que serviram de base para as teorias de ensino-aprendizagem que mais influenciaram o ensino-aprendizagem de língua estrangeira em nossa cultura (Williams & Burden, 1997; Rego, 2004; Vygotsky, 1993,2003), as teorias de linguagem (Graddol, 1994; Hutchinson & Waters 1987; Bloor & Bloor, 1995), considerações sobre material didático (Cunningsworth, 1984, 1995; Tomlinson, 1998; Graves, 2000), o conceito de tarefa segundo Ellis (2003), os critérios de avaliação de software (Squires & McDougall, 1997; Stirling, 1998; Alagumali & Anderson, 1997) e os critérios de avaliação de Ramos (1998) e Freire et al. (2004). A pesquisa revelou que, embora as teorias de linguagem e de ensino-aprendizagem que embasam o software contrariam os paradigmas educacionais vigentes segundo os Parâmetros Curriculares Nacionais Língua Estrangeira (Brasil, 1998) e os Parâmetros Curriculares Nacionais Ensino Médio (Brasil, 1999), do ponto de vista tecnológico apresenta recursos que podem auxiliar a professores e alunos no processo de ensino-aprendizagem

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The structure of the Swedish public library field has been evolving during the last decades. The traditional mission of educating the citizens to become responsible, democratic and knowledgeable members of society has in a way led to the integration between public and school libraries. Lately new co-operational models have been under debate and a sense of resistance has arisen because of the economical and market influences. In parallel with closure of library branches new libraries have evolved in malls and wash houses and some with self-service with no use of librarians. This work shows how co-operation in rural areas finds the common goals for the people living there who are concerned about keeping the service needed including the public library and thus using existing means and crossing borders of commercial thinking. Participators in the project are interviewed to find out their various wishes and a mutual goal. The degree of local democracy is also investigated. The outcome of this thesis is that in rural areas with tough municipal economy the citizens co-operate over borders to keep the services they want, and in this specific case it is found to be a meeting spot in the centre of the village, where also the library will be located, together with the country store.

Packaging is a topic under debate and scrutiny intoday’s society, due to its obvious environmentaldetriment – but also the business opportunities – tied tominimizing or even eliminating packaging.therefore, in this thesis, the aim is to introduce Chinesetea culture to the Swedish through packaging design,By tea culture studies and surveys of the Swedishmarket, with less is more, and minimalism designtheory to design elegant and Sustainable package. Withthis design, convey the Chinese tea ceremony cultureand Zen philosophy.Through the study of Chinese tea culture, then analysiscurrent tea packaging on Chinese and Swedish markets,from the structure, color, material...every aspects ofpackaging design to show the Chinese tea culture in theSwedish market.4According to our respondents and theory, packaging isa big component in a brand's marketing strategy and tocommunicate the brand’s message and values.Marketing information can be designed into visualelements that are used on the package to communicatea message which could speak out the consumers'emotions. But packaging is a topic under debate andscrutiny in today’s society, due to its obviousenvironmental detriment – but also the businessopportunities.So, how to balance the commercial and environmentalthose two aspects and how to express sustainabledesign in my project, is the major issues I have to figureout.Key words: Chinese tea culture, less is more,sustainable packaging design, graphic design, Zen andtea ceremony, tea business marketing