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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.
101

Termodinamica do equilibrio aplicada a destilação etanol-agua

Giordano, Roberto de Campos 12 August 1985 (has links)
Orientador: Saul Gonçalves D'Avila / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Campinas / Made available in DSpace on 2018-07-16T09:04:09Z (GMT). No. of bitstreams: 1 Giordano_RobertodeCampos_M.pdf: 4794824 bytes, checksum: 4993751b8b1af3163e64a40e615f8cf7 (MD5) Previous issue date: 1985 / Resumo: Propõe-se método para o teste da consistência termodinâmica de dados experimentais de equilíbrio líquido-vapor para sistemas binários, através da integração da equação da coexistência. Este método dispensa a utilização de correlações para o coeficiente de atividade e pressões de saturação, tendo se mostrado de boa sensibilidade. A seguir, o método da equação da coexistência é utilizado na análise da consistência dos dados etanol-água da literatura. Desta forma, selecionam-se conjuntos de dados isotérmicos aos quais são ajustadas equações para o coeficiente de atividade, com parâmetros dependentes da temperatura, o que melhora sensivelmente o ajuste. As equações UNIQUAC e de van Laar são as que apresentam melhores resultados. As correlações assim obtidas são usadas na simulação da destilação do álcool etílico através do modelo de coluna de Naphtali-Sandholm. Analisa-se, por fim, a influência de simplificações nos cálculos termodinâmicos sobre os resultados desta simulação. / Abstract: A method for testing the thermodynamic consistency of experimental liquid-vapor equilibrium data for binary systems through the integration of the coexistence equation is proposed. This method exempts from the use of correlations for both the activity coefficient and saturation pressures and shows a good sensibility. The coexistence equation method is then used for checking the consistency of ethanol-water data, found in the literature. In this way, groups of isothermal data are selected and equations for the activity coefficient, with temperature dependent parameters, are adjusted to them, improving the fit. The UNIQUAC and van Laar equations show the best results. The obtained correlations are used for simulating the destillation of ethyl alcohol through the model of Naphtali Sandholm. The influence of some simplifications in the thermodynamic calculations over the simulation results is verified. / Mestrado / Mestre em Engenharia Química
102

Utilização da equação de clausius-clapeyron na correlação e predição de propriedades termodinamicas

Tofik, Clovis Sawaia 19 July 2018 (has links)
Orientador: Saul Gonçalves d'Avila / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Campinas / Made available in DSpace on 2018-07-19T05:39:57Z (GMT). No. of bitstreams: 1 Tofik_ClovisSawaia_M.pdf: 1947071 bytes, checksum: 466e1a8d4b6093e6fc458423d1dfc4c6 (MD5) Previous issue date: 1984 / Resumo: A presente tese descreve os trabalhos desenvolvidos no estabelecimento de dois novos métodos para predição de pressão de vapor e de uma metodologia para geração de dados de entalpia de vaporização, adequados para compostos apolares e polares. Um dos métodos de predição de pressão de vapor baseia-se na integração numérica da equação de Clausius-Clapeyron. Outro, baseia-se na generalização das constantes da equação de Abrams-Massaldi-Prausnitz, derivada da teoria cinética de fluidos poliatômicos devida a Moelwyn-Hughes, utilizando-se a equação de Clausius-Clapeyron como restrição. A metodologia proposta para geração de dados de entalpia de vaporização foi desenvolvida utilizando-se a equação de Clausius-Clapeyron, acoplada a correlações para predição de volumes do liquido e do vapor saturados. Os métodos propostos apresentaram bons resultados na predição de propriedades de compostos polares, sendo de especial interesse para aplicação a compostos da industria alcoolquímica. Apresenta-se, também, uma analise critica das correlações existentes na literatura para predição de dados de volume do liquido e do vapor saturado / Abstract: The present thesis describes the work undertaken to develop two methods for predicting vapor pressures and a methodology for calculating enthalpy of vaporization data, applicable to non-polar and polar compounds. The prediction methods of vapor pressures are based both on the numerical integration of the Clausius-Clapeyron equation and on the generalization of the constants in the Abrams-Massaldi-Prausnitz vapor-pressure equation. This equation has been derived from a kinetic theory of polyatomic fluids first suggested by Moelwyn-Hughes. The generalized constants are determined by imposing the Clausius-Clapeyron equation as a restrictive condition. The methodology proposed for calculating enthalpy of vaporization data has been developed through the Clausius-Clapeyron equation coupled with other correlations for estimating saturated liquid and vapor volumes. All proposed methods showed to be accurate in the prediction of thermodynamic properties of polar compounds and have been mainly applied to substances of interest in the Brazilian alcoholchemical industries. Finally, a critical review of existing correlations for determining volumetric data of saturated liquids and vapors is presented / Mestrado / Mestre em Engenharia Química
103

Coeficiente de atividade pelo metodo do arraste

Morais, Ana Lucia Ferreira de 05 February 1993 (has links)
Orientador: Saul Gonçalves D'Avila / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-07-19T04:49:26Z (GMT). No. of bitstreams: 1 Morais_AnaLuciaFerreirade_M.pdf: 3141389 bytes, checksum: e4df3abb5fd1d6da3b3e49f59f73c9b4 (MD5) Previous issue date: 1993 / Resumo: Este trabalho trata do projeto e construção de uma aparelhagem visando avaliar o potencial do Método do Arraste na obtenção de coeficiente de atividades a infinita diluição e a concentração finita. Foi desenvolvida uma metodologia experimental e de cálculo, tendo sido testada na coleta de dados isotérmicos dos sistemas n-heptano/n-metil-pirrolidona (NMP), benzeno/NMP e etanol/água na faixa de '25GRAUS¿C a '55GRAUS¿C.Foram determinados os limites de aplicabilidade da aparelhagem, que mostrou-se apropriada para a determinação dos coeficientes de atividade dos componentes voláteis de uma mistura líquida / Abstract: This work treats the design and construction of na apparatus to avaluate the potential of the Stripping Method fot determination of activity coefficients at infinite dilution and at finite concentration. An experimental and calculation methodology has been developed and tested to measure isothermal data of systems n-heptane/ n-methylpyrrolidone (NMP), benzene/NMP and ethanol/ water in the range '25GRAUS¿C to '55GRAUS¿C. Its was found the limits of applicability for the apparatus, that is suitable for determining activity coefficient of the volatile compounds of a liquid mixture / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química
104

Vapour-liquid equilibria : measurement and prediction by an analytical group solution model.

Ronc, Michel Joseph. January 1973 (has links)
No description available.
105

Vapor pressures and saturated liquid and vapor densities of isomeric heptanes and octanes /

McMicking, James Harvey January 1961 (has links)
No description available.
106

The nonideality of liquid and solid orthopara deuterium solutions from vapor pressure measurements /

Meckstroth, Wilma Koening January 1968 (has links)
No description available.
107

The effect of molecular size on vapour liquid equilibria /

Dutta, Mamata January 1969 (has links)
No description available.
108

A detailed study of the near infrared spectrum of water vapor /

Pugh, Larry Anderson January 1972 (has links)
No description available.
109

Vapor-liquid equilibrium relations in non-ideal systems. The binary systems: hexamethyldisiloxane-toluene hexamethyldisiloxane-ethyl alcohol and ethyl alcohol-toluene at 40,50,60, and 70̊C /

Guzman, Jorge A. January 1973 (has links)
No description available.
110

Vapor transport techniques for growing macroscopically uniform zinc oxide nanowires

Baker, Chad Allan 2009 August 1900 (has links)
ZnO nanowires were grown using carbothermal reduction and convective vapor phase transport in a tube furnace. Si <100> substrates that were 20 mm x 76.2 mm were sputter coated with 2 nm to 50 nm gold which formed nanoparticles on the order of 50 nm in diameter through a process of Ostwald ripening upon being heated. Growth temperatures were varied from 800ºC to 1000ºC, flow rates were varied from 24 sccm to 3300 sccm, and growth durations were varied from 8 minutes to 5 hours. Vapor phase Zn, CO, and CO2, produced by carbothermal reduction and suspended in an Ar atmosphere, were flowed over the Si substrates. The Au nanoparticles formed an eutectic alloy with Zn, causing them to become liquid nanodroplets which catalyzed vapor-liquid-solid nanowire growth. The nanowires were also synthesized by self-catalyzing vapor-solid growth in some cases. Using the tube furnace never resulted in more than 50% of the substrate being covered by nanowires. It was found that a bench-top furnace could achieve nearly 100% nanowire coverage by placing the 20 mm x 76.2 mm sample face down in a quartz boat less than 2 mm above the source powder. This was because minimizing the distance between the sample and the source powder was critical to achieve macroscopically uniform growth consistently. / text

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