Made available in DSpace on 2014-06-11T19:35:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-03Bitstream added on 2014-06-13T19:05:51Z : No. of bitstreams: 1 napoleao_das_dr_guara.pdf: 1233136 bytes, checksum: e1780c6a0f02e82cd3c85543e0c3f36c (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os sistemas de refrigeração por absorção da mistura amônia-água têm sido amplamente utilizados e referenciados na literatura. Normalmente, os modelos encontrados para análises são baseados considerando-se, dados de tabelas e diagramas para a entalpia em função da concentração. Para a análise de tabelas e diagramas de entropia em função da concentração de amônia na mistura, não se detém a mesma atenção, existindo ausência de dados disponíveis na literatura para esta propriedade termodinâmica. Estes sistemas apresentam-se complexos quanto aos parâmetros físico-químicos, tornando-se necessário um estudo mais aprofundado e detalhado da termodinâmica associada, corroborando para a determinação da inter-relação da entropia com outras propriedades associadas a refrigeração. Neste trabalho são formulados modelos de cálculos para o levantamento da entropia em função da temperatura, pressão e concentração de misturas amônia-água S = S (T, P, x). A confecção dos diagramas de entropia na fase líquido-vapor foram determinados visando auxiliar projetos industriais através de análises energéticas e exergéticas, simulação e otimização de processos relacionados ao sistema de refrigeração por absorção. / Refrigeration systems of the ammonia-water mixtures by absorption have been widely used and referred in the literature. Usually the models found for analyses are based taking in to account data of tables and diagrams for the enthalpy as a function of the concentration. For the analysis of tables and entropy diagrams in function of the concentration of ammonia in the mixture, it has not been taken the same attention, existing lack of available data in the literature for that thermodynamic property. These systems seem to be complex as for the physiochemical parameters, becoming necessary a deeper and detailed study on the associated thermodynamics, corroborating to determine the interrelation of the entropy with other associated refrigeration properties. In this work, calculation models to improve the entropy are formulated in function of temperature, pressure and concentration of the ammonia-water mixtures S = S (T, P, x). The performance of the entropy diagrams in the liquid-vapor phase was surely aiming to aid industrial projects through energy analyses and exergetic simulation and optimization of processes related to the system of cooling by absorption.

Made available in DSpace on 2014-06-11T19:28:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-12-12Bitstream added on 2014-06-13T18:57:54Z : No. of bitstreams: 1 bruno_ep_me_guara.pdf: 714704 bytes, checksum: 551c99845af4bf7d520a176c8e24c7b4 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O motor de combustão interna é uma máquina existente há mais de um século, sendo muito utilizado em aplicações industriais e de transporte. Uma pesquisa para se obter informações dessa máquina revelou que existe bastante literatura especializada sobre o assunto. Foi desenvolvido o cálculo termodinâmico a partir dos dados do projeto, com a finalidade de se obter o diâmetro do pistão e o seu curso. Este trabalho desenvolve procedimentos para o projeto do motor monocilíndrico, seguindo uma metodologia para se obter o desenho de conjunto, os detalhes, ajustes e tolerância. Em seguida foi realizado um estudo para implementar as etapas de usinagem das peças utilizando máquinas convencionais e de controle numérico. Finalmente, realizou-se a montagem dos subconjuntos obtendo-se enfim a parte alternativa do motor. / The internal combustion engine exists since a century ago; its main application is in the industry and in the mobile machines in general. A research to obtain information about this kind of machine revealed a rich specialized literature. It was developed the thermodynamic calculation starting from the data related to this work, in order to obtain the piston diameter and its stroke. This work still develops procedures related to mechanical design of the alternating parts of a one cylinder engine and its support such as the block, the crankcase and the cylinder. The assembly drawing and the detailed drawing of each part were also attained. A study to implement the various phases of machining of parts making use of conventional and numerically controlled machines was also developed. Finally, the parts were assembled and the alternative group get running.

Made available in DSpace on 2014-10-09T12:42:52Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:03Z (GMT). No. of bitstreams: 1 05026.pdf: 15504738 bytes, checksum: a9ee04810e777929af2a6dd91c0227ac (MD5) / Tesis(Doctoral) / IPEN/T / Universidad Autonoma de Madrid, Facultad de Ciencias, Espanha

Made available in DSpace on 2014-10-09T12:42:52Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:03Z (GMT). No. of bitstreams: 1 05026.pdf: 15504738 bytes, checksum: a9ee04810e777929af2a6dd91c0227ac (MD5) / Tesis(Doctoral) / IPEN/T / Universidad Autonoma de Madrid, Facultad de Ciencias, Espanha

A majority of tornado research focuses on the Great Plains region of the United States. Knowledge of tornado environments outside of the Great Plains is limited; this is especially true for the Southeast U.S. In addition, little is known about the role of the lower troposphere on tornadogenesis. Therefore, this study examines low-level thermodynamic parameters associated with tornadoes in the Southeast U.S between 1960 and 2002. Previous studies have shown that higher values of CAPE, 0-3 km CAPE, 0-1 and 0-3 km SRH, and 0-1 and 0-1 km EHI are more likely associated with significant tornadoes. Similar studies have shown that decreasing LCL, LFC heights, and CIN are common with significant tornadoes. This study supports that higher values of shear and instability/shear and lower CIN values are associated with significant tornadoes in the Southeast. However, this study indicates that instability, LCL, and LFC heights may be poor tornado strength discriminators.

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