Bubbles
Mostrando 25-36 de 209 artigos, teses e dissertações.
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25. EXPERIMENTAL STUDY OF ELONGATED BUBBLES IN HORIZONTAL TWO-PHASE INTERMITTENT FLOW / ESTUDO EXPERIMENTAL DE BOLHAS ALONGADAS NO ESCOAMENTO BIFÁSICO HORIZONTAL INTERMITENTE
The present work experimentally studied several relevant dynamic characteristics of gas-liquid intermittent flow through a horizontal pipe. All tests were performed in a test section formed by 50.8 mm internal diameter pipe using air and water as working fluids. The tests covered a region where the flow undergoes a complex transition from elongated bubble fl
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 04/04/2012
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26. A Common-Feature Approach for Testing Present-Value Restrictions with Financial Data
It is well known that cointegration between the level of two variables (labeled Yt and yt in this paper) is a necessary condition to assess the empirical validity of a present-value model (PV and PVM, respectively, hereafter) linking them. The work on cointegration has been so prevalent that it is often overlooked that another necessary condition for the PVM
Escola de Pós-Graduação em Economia da FGV. Publicado em: 24/02/2012
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27. Investigation of hydrodynamics and transition regime in an internal loop airlift reactor using CFD
CFD modeling for an internal loop airlift reactor is developed for different superficial gas velocities, ranging from 0.015 to 0.073 m/s. Based on the presence of gas bubbles in the downcomer, three regimes can be generally classified as: no gas bubbles (I), stagnation of gas bubbles (II), and recirculation of gas bubbles into the riser (III). The aim of the
Braz. J. Chem. Eng.. Publicado em: 2012-12
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28. Dynamics of gas bubble growth in oil-refrigerant mixtures under isothermal depressurization
This paper proposes a numerical model to predict the growth of gaseous refrigerant bubbles in oil-refrigerant mixtures with high contents of oil subjected to isothermal depressurization. The model considers an Elementary Cell (EC) in which a spherical bubble is surrounded by a concentric and spherical liquid layer containing a finite amount of dissolved liqu
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2012-06
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29. Simple model for CO2 absorption in a bubbling water column
A simple analytical model is presented for the time-evolution of dissolved CO2 concentration in a batch water column. The application in mind is the removal of the CO2 produced by the propulsion plant of a submarine cruising underwater. The model is based on a constant number of constant size CO2 bubbles within the water column, with uniform gas injection th
Brazilian Journal of Chemical Engineering. Publicado em: 2012-03
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30. O uso de cópulas para gestão de riscos
The large number of publications in finance using currently copulas can be explained by the ability of this technique to deal with statistical evidence of non-normality of the return series of financial assets. The non-normality is evidenced by the "volatility smile" in the series of stock options near expiration, the existence of "heavy tails" in portfolios
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2012
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31. Comunicação e crise na era da cibercultura: lógica mediática da hipervolatilização financeira contemporânea
A presente Dissertação versa sobre a relação entre o fenômeno glocal e a hipervolatilização financeira do capitalismo cibercultural. Fio condutor da reflexão, o fenômeno glocal é a hibridação entre contexto local e cultura mundial satelitizada, mescla inextricável articulada e modulada pela comunicação instantânea e aprofundada com a prolifer
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 15/12/2011
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32. Remoção de matéria orgânica carbonácea e nitrogênio em Reator Aeróbio-Anóxico de Leito Fixo (RAALF) aplicado ao pós-tratamento de efluente de reator anaeróbio / Removal of carbonaceous organic matter and nitrogen in an Aerobic-Anoxic Fix Bed Reactor (AAFBR) applied to the tertiary treatment of domestic wastewater
This work presents the Aerobic-Anoxic Fix Bed Reactor (AAFBR), with superimposed chambers, as an alternative concerning the post-treatment of anaerobic reactors efiluents aiming the removal of carbonaceous organic matter and nitrogen. Polyurethane foam cubic matrices (5 mm) were used packing material. Hydrodynamic essays were carried out in order to obtain t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/07/2011
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33. ATUAÇÃO DE BENTONITE E POLIVINILPOLIPIRROLIDONA (PVPP) NA CLARIFICAÇÃO DE VINHOS ESPUMANTES / PERFORMANCE OF BENTONITE AND POLYVINYLPOLYPYRROLIDONE (PVPP) IN THE CLARIFICATION OF SPARKLING WINE
The size and persistence of the bubbles is one of the characteristics pursued by consumers of sparkling wine. The perlage is closely linked to nitrogen products, usually proteins of low molecular weight. Furthermore, bentonite and polyvinylpolypyrrolidone (PVPP) are glues used both in cleaning up the base wine and the sparkling wines, in other words, the fer
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/04/2011
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34. Estudo numérico e experimental de uma coluna de bolhas operando em regime heterogêneo / Numerical and experimental study of a bubble column operating in heterogeneous regime
Os principais problemas da simulação da fluidodinâmica em sistemas gás-líquido por CFD são as simplificações do comportamento dinâmico das bolhas. Na maioria dos processos industriais com escoamento gás-líquido em colunas de bolhas, as bolhas estão em velocidades altas e a coluna opera em regime heterogêneo. Existe ainda a influência da geometr
Publicado em: 2011
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35. Mecanismos de floculação com polímeros hidrossolúveis, geração de flocos aerados, floculação em núcleos de bolhas floculantes e aplicações na separação de partículas modelos por flotação
A presente tese de doutorado apresenta estudos avançados de floculação com diferentes polímeros (poliacrilamidas), investigando os mecanismos da geração de flocos aerados e o desenvolvimento de técnicas de caracterização de sistemas multifásicos (bolhas, polímeros e sólidos) para aprimorar a separação de partículas por flotação utilizando su
Publicado em: 2011
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36. Metallographic analysis of the internal microstructure of orthodontic mini-implants
Effective orthodontic anchorage may be obtained by miniimplants inserted into the maxillary bones. However, the risk of miniimplant failure is one of the most important issues, especially the rupture of its structure referred to as fracture, mainly due to metal deficiencies. This study analyzed the internal microstructure of orthodontic mini-implants, ascert
Brazilian Oral Research. Publicado em: 2010-12