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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Sobre a vivência da condição juvenil: um estudo com jovens egressos do Projovem Urbano (2008-2010) da cidade do Rio de Janeiro / About the living of juvenile condition: a study of young egresses of Projovem Urbano (2008-2010) of the city of Rio de Janeiro

Márcia Teixeira Pinto 01 June 2012 (has links)
Essa dissertação tem por objetivo compreender como, numa sociedade marcada pela desigualdade, jovens pobres experimentam a condição juvenil. Para tanto se caracterizou a situação familiar, a experiência escolar e laboral bem como, as práticas de sociabilidade dos jovens egressos selecionados do Projovem Urbano, procurando perceber em que medida a participação num Programa voltado para jovens pobres contribuiu para criação de estratégias que viabilizem os projetos de futuro desses jovens. Partimos do pressuposto que Juventude é uma categoria construída socialmente, não podendo ser compreendida de forma monolítica e objetivamente dada. Condição social, etnia, gênero, origem regional, territorial, bem como a fase da vida, influenciam na forma de experimentar a condição juvenil. Pela natureza das questões, optou-se por uma abordagem qualitativa associando revisão bibliográfica e pesquisa de campo onde as realizações de entrevistas aprofundadas semi - estruturadas e a análise de documentos relacionados ao tema constituíram os elementos centrais do campo. Foram realizadas entrevistas aprofundadas com 14 jovens, concluintes do Projovem Urbano (2008-2010), na cidade do Rio de Janeiro, de ambos os sexos (8 mulheres e 6 homens) e com idade entre 20 e 30 anos, agrupados em faixa etária ( 20 a 25 anos e 26 a 30 anos). Ao final desse estudo nos foi possível entender que o acesso desigual às oportunidades para se vivenciar esse período, reduzem as possibilidades de experimentação da condição juvenil. / This dissertation aims to understand how, in a society marked by inequality, poor youth experience the juvenile condition. For that it has been characterized the family situation, school and work experience as well as the practices of sociability of young graduates selected from the Projovem Urbano ( 2008-2010), seeking to understand to what extent participation in a program focusing on poor youth contributed to creating strategies that enable the future projects of these young people. We assume that youth is a category socially constructed, could not be understood monolithically and objectively given. Social condition, ethnicity, gender, regional and territorial origin, as well as the stage of life, are determining factors in the way of experiencing the young condition. By the nature of the issues, it has been chosen a qualitative approach associating literature review and field research where the realization of in-depth semi structured interviews and the analysis of documents related to the theme were the central elements of the field. Depth interviews were conducted with 14 youngsters, graduates of the Projovem Urbano (2008-2010) in the city of Rio de Janeiro, of both sexes (eight women and six men) aged between 20 and 30 years, divided into age groups (20-25 years and 26-30 years). At the end of this study we were able to understand that unequal access to opportunities to experience this period, reduce the possibilities of experiencing the juvenile condition by poor youth.
2

Sobre a vivência da condição juvenil: um estudo com jovens egressos do Projovem Urbano (2008-2010) da cidade do Rio de Janeiro / About the living of juvenile condition: a study of young egresses of Projovem Urbano (2008-2010) of the city of Rio de Janeiro

Márcia Teixeira Pinto 01 June 2012 (has links)
Essa dissertação tem por objetivo compreender como, numa sociedade marcada pela desigualdade, jovens pobres experimentam a condição juvenil. Para tanto se caracterizou a situação familiar, a experiência escolar e laboral bem como, as práticas de sociabilidade dos jovens egressos selecionados do Projovem Urbano, procurando perceber em que medida a participação num Programa voltado para jovens pobres contribuiu para criação de estratégias que viabilizem os projetos de futuro desses jovens. Partimos do pressuposto que Juventude é uma categoria construída socialmente, não podendo ser compreendida de forma monolítica e objetivamente dada. Condição social, etnia, gênero, origem regional, territorial, bem como a fase da vida, influenciam na forma de experimentar a condição juvenil. Pela natureza das questões, optou-se por uma abordagem qualitativa associando revisão bibliográfica e pesquisa de campo onde as realizações de entrevistas aprofundadas semi - estruturadas e a análise de documentos relacionados ao tema constituíram os elementos centrais do campo. Foram realizadas entrevistas aprofundadas com 14 jovens, concluintes do Projovem Urbano (2008-2010), na cidade do Rio de Janeiro, de ambos os sexos (8 mulheres e 6 homens) e com idade entre 20 e 30 anos, agrupados em faixa etária ( 20 a 25 anos e 26 a 30 anos). Ao final desse estudo nos foi possível entender que o acesso desigual às oportunidades para se vivenciar esse período, reduzem as possibilidades de experimentação da condição juvenil. / This dissertation aims to understand how, in a society marked by inequality, poor youth experience the juvenile condition. For that it has been characterized the family situation, school and work experience as well as the practices of sociability of young graduates selected from the Projovem Urbano ( 2008-2010), seeking to understand to what extent participation in a program focusing on poor youth contributed to creating strategies that enable the future projects of these young people. We assume that youth is a category socially constructed, could not be understood monolithically and objectively given. Social condition, ethnicity, gender, regional and territorial origin, as well as the stage of life, are determining factors in the way of experiencing the young condition. By the nature of the issues, it has been chosen a qualitative approach associating literature review and field research where the realization of in-depth semi structured interviews and the analysis of documents related to the theme were the central elements of the field. Depth interviews were conducted with 14 youngsters, graduates of the Projovem Urbano (2008-2010) in the city of Rio de Janeiro, of both sexes (eight women and six men) aged between 20 and 30 years, divided into age groups (20-25 years and 26-30 years). At the end of this study we were able to understand that unequal access to opportunities to experience this period, reduce the possibilities of experiencing the juvenile condition by poor youth.
3

Varia??o espacial na estrutura das assembleias de peixes jovens em tr?s lagunas com diferentes gradientes de salinidade no Estado do Rio de Janeiro / Spatial variation in structure of juvenile fish assemblages in three coastal lagoons with different salinity gradient in Rio de Janeiro State

FRANCO, Taynara Pontes 22 February 2013 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-10-23T18:42:10Z No. of bitstreams: 1 2013 - Taynara Pontes Franco.pdf: 1292257 bytes, checksum: 6adb092b864fac2081ba5afb46e52d2e (MD5) / Made available in DSpace on 2018-10-23T18:42:10Z (GMT). No. of bitstreams: 1 2013 - Taynara Pontes Franco.pdf: 1292257 bytes, checksum: 6adb092b864fac2081ba5afb46e52d2e (MD5) Previous issue date: 2013-02-22 / FAPERJ / Coastal lagoons can have different salinity gradient depending on the geographical position, hydrological balance, type of sea connection and other environmental conditions, which influence structure of fish assemblages that uses these systems. The aim of this study was to assess the use of ichthyofauna and eventual changes in structure of fish assemblages in relation to environmental variables, mainly the salinity, in three choked lagoon systems of the coastal lowlandsof Rio de Janeiro State (Maric?, Saquarema and Araruama). The raised hypothesis wasthat different fish assemblages use lagoons with different salinity gradient and that the species richness is directly associated to salinity with optimum at normal marine water (36), and that changes above or below this value can limit occurrence of species. Beach seines and environmental variables measurements were performed during the winter 2011 and the summer 2012. Three zones determined according to distance from the connection with the sea (Inner zone ? the farthest area from the channel that connect the lagoon to the sea with lesser marine influence; Middle zone ? the central part of the lagoon; and Outer zone - next to the channel thatconnect the lagoon to the sea, with more marine influence) and ten sites evenly distributed in each lagoon were sampled in three replicates, totaling 168 samples. Environmental variables of salinity, temperature, depth, transparency and turbidity were measured in each sampling occasion. Considering all pooled samples, the environmental variables that most contributed to lagoon separation was the salinity (higher in Araruama and lower in Maric?) and temperature between the two sampled periods (winter and summer). A total of 57,083 fishes were collected in 44 species. The more representative families were Gerreidae with six species, Clupeidae and Gobiidae with cinco species and Sciaenidae with four species. Twenty species were common to the three lagoons with more represented species being Atherinella brasiliensis and Anchoa januaria with frequency of occurrence higher than 65%. Despite of differences in environmental gradient, mainly the salinity, only the fish assemblage of Araruama lagoon differed from the other two lagoons, although with high fish sobreposition. The highest richness found in the hyperhaline Araruama lagoon (32 esp?cies) was very close of fish richness in the Saquarema lagoon (30 species), although the latter had a much smaller area, which confirm the hypothesis that the highest richness occur in salinity near to the marine water salinity. Differences in environmental conditions among the three lagoon zones were significantly only in Maric? lagoon, which may be related to its estuarine conditions. Salinity, transparency and turbidity were the most important factors influences fish assemblages depending on the lagoon, with Maric? having a higher influence of transparency on fish assemblages, while the turbidity had higher influence during the Summer in Saquarema and Araruama fish assemblages. Such information are a baseline to future evaluation of the environmental condition of these systems aiming the resources conservation, but other studies need to be incorporate to these analyses, mainly the influences of physical habitat on fish assemblages structure. / Lagunas podem assumir diferentes gradientes de salinidade dependendo de sua localiza??o geogr?fica, balan?o h?drico, conex?o com mar e outras condi??es ambientais, as quais influenciam a estrutura das assembleias de peixes que utilizam esses ambientes. O objetivo deste trabalho foi avaliar o uso da ictiofauna e eventuais varia??es na estrutura das assembleias de peixes em rela??o ?s vari?veis ambientais, principalmente o gradiente de salinidade em tr?s sistemas lagunares sufocados da Baixada Litor?nea do Estado do Rio de Janeiro (Maric?, Saquarema e Araruama). A hip?tese testada foi a de que diferentes assembleias de peixes usam lagunas com diferentes gradientes salinos, e que a riqueza de esp?cies ? diretamente associada a salinidade at? o valor da salinidade normal da ?gua do mar (36), e que varia??es acima ou abaixo destes n?veis poderiam restringir a ocorr?ncia das esp?cies. Arrastos de praia e medi??es de vari?veis ambientais foram realizados durante o Inverno de 2011 e Ver?o de 2012. Tr?s zonas foram determinadas a partir da dist?ncia da conex?o com o mar (Zona Interna ? mais distante do canal de conex?o com o mar e com menor influ?ncia marinha; Zona Central ? parte mais central da laguna, e Zona Externa ? mais pr?xima do canal de conex?o com o mar e com maior influ?ncia marinha) e dez locais de coleta foram amostrados, com tr?s r?plicas cada, distribu?dos entre estas zonas em cada laguna, totalizando 168 amostras. Vari?veis ambientais de salinidade, temperatura, profundidade, transpar?ncia e turbidez foram medidas em cada arrasto realizado. Considerando todo o conjunto de amostras, as vari?veis ambientais que mais contribu?ram para a separa??o das lagunas foram salinidade (maior em Araruama e menor em Maric?) e a temperatura entre os dois per?odos de coleta (Inverno e Ver?o). Foram coletados 57.083 indiv?duos em 44 esp?cies de peixes. As fam?lias de maior representatividade foram Gerreidae com seis esp?cies, Clupeidae e Gobiidae com cinco esp?cies e Sciaenidae com quatro esp?cies. Vinte esp?cies foram comuns ?s tr?s lagunas e as esp?cies de maior representatividade entre elas foram Atherinella brasiliensis e Anchoa januaria com frequ?ncia de ocorr?ncia superiores a 65%. Apesar das diferen?as no gradiente ambiental, principalmente na salinidade, somente a assembleia de peixes de Araruama diferiu das demais, embora com grande sobreposi??o de esp?cies. A maior riqueza foi encontrada na laguna hipersalina de Araruama (32 esp?cies), por?m muito pr?xima da riqueza na laguna de Saquarema (30 esp?cies), embora com esta ?ltima tendo uma ?rea bem menor, o que confirma a hip?tese de maior riqueza em salinidade pr?xima da ?gua do mar. As diferen?as nas condi??es ambientais existentes entre as zonas das lagunas somente foram significativas na laguna de Maric?, o que pode estar relacionado ao seu car?ter estuarino. A salinidade, transpar?ncia e turbidez foram os fatores que mais influenciaram as assembleias de peixes, com diferentes graus de influ?ncia dependendo da laguna, com Maric? tendo maior influ?ncia da transpar?ncia na assembleia de peixes, enquanto a turbidez teve maior influ?ncia no ver?o nas assembleias de peixes em Saquarema e Araruama. Estas informa??es servem de base para futuras avalia??es da condi??o ambiental deste sistema visando a conserva??o destes recursos, por?m outros estudos devem ser incorporados nas an?lises, principalmente as influ?ncias do habitat f?sico na estrutura das assembleias de peixes.
4

Conception d’un onduleur triphasé à base de composants SiC en technologie JFET à haute fréquence de commutation / Design of a 3-phase inverter using SiC JFETs for high frequency applications

Fonteneau, Xavier 12 June 2014 (has links)
Depuis le début des années 2000, les composants en carbure de silicium (SiC) sont présents sur le marché principalement sous la forme de diodes Schottky et de transistors FET. Ces nouveaux semi-conducteurs offrent des performances en commutation bien supérieures à celles des composants en silicium (Si) ce qui se traduit par une diminution des pertes et une réduction de la température de fonctionnement à système de refroidissement identique. L’utilisation de composants SiC ouvre donc la possibilité de concevoir des convertisseurs plus compacts ou à une fréquence de commutation élevée pour une même compacité. C’est avec cet objectif d’augmentation de la fréquence de commutation qu’a été menée cette étude axée sur l’utilisation de composants SiC au sein d’un onduleur triphasé. Le convertisseur sur lequel se base l’étude accepte une tension d’entrée de 450V et fournit en régime nominal un courant de sortie efficace par phase de 40 A. Le choix des composants SiC s’est porté sur des transistors JFET Normally-Off et des diodes Schottky SiC car ces composants étaient disponibles à la vente au début de ces travaux et offrent des pertes en commutation et en conduction inférieures aux autres structures en SiC. Les transistors FET possèdent une structure et des propriétés bien différentes des IGBT habituellement utilisés pour des convertisseurs de la gamme considérée notamment par leur capacité à conduire un courant inverse avec ou sans diode externe. De ce fait, il est nécessaire de développer de nouveaux outils d’aide au dimensionnement dédiés à ces composants SiC. Ces outils de calculs sont basés principalement sur les paramètres électriques et thermiques du système et sur les caractéristiques des composants SiC. Les premiers résultats montrent qu’en autorisant la conduction d’un courant inverse au sein des transistors, il est possible de diminuer le nombre de composants. Basées sur ces estimations, une maquette de bras d’onduleur a été développée et testée. Les premiers thermiques montrent que pour une puissance de 12kW, il est possible d’augmenter la fréquence de commutation de 12 kHz à 100 kHz. / Since 2000, Silicon Carbide (SiC) components are available on the market mainly as Schottky diodes and FET transistor. These new devices provide better switching performance than Silicon (Si) components that leads to a reduction of losses and operating temperatures at equivalent cooling system. Using SiC components allows to a better converter integration. It is in this context that ECA-EN has started this thesis dedicated to using SiC devices in a three-phase inverter at high switching frequency. The converter object of this study is supply by a input voltage of 450V and provides a current of 40A per phase. The components used for these study are SiC Normally-Off JFET and Schottky Diodes because these devices were commercialized at the begining of this thesis and offer better switching performance than others SiC components. FET transistors have a different structure compared to traditionnal IGBT especially their capability to conduct a reverse current with or without body diode. So it is necessary to develop new tools dedicated to the design of converters built with SiC components. These tools are based on the electrical properties of the converters and the statics and dynamics characteristics of the transistor and the diode. The results show that when the transistors conduct a reverse current, the number of components/dies can be reduced. According to data, a PCB board of an inverter leg has been built and tested at ECA-EN. The thermal measurement based on the heatsink shows that the switching frequency of an inverter leg can be increased from 12 to 100 kHz for an ouput power of 12kW.

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