Van Der Waals Equation
Mostrando 1-12 de 20 artigos, teses e dissertações.
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1. Evaluation of the Direct Interaction between Amino Acids and Glutathione-Coated CdTe Quantum Dots and Application in Urinalysis for Histidine Determination
The present work aimed to direct amino acid (AA) sensing by quantum dots (QD) and development of an analytical method for potential fast clinical tests. Notably, AA with a positive charge or neutral polar chains, namely L-histidine (His) and L-threonine (Thr), responded to glutathione-coated CdTe (GSH-CdTe) (ΔF ≤ 90%, variation of fluorescence intensity).
J. Braz. Chem. Soc.. Publicado em: 2021-03
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2. PHASE BEHAVIOR DATA AND THERMODYNAMIC MODELING OF THE BINARY SYSTEM {CO2 + COUMARIN} AT HIGH PRESSURES
Abstract In this work, vapor - liquid (VLE) equilibrium for the binary system carbon dioxide (1) + coumarin (2) at high pressures was measured by a static synthetic method using a variable-volume view cell. Experimental data were obtained in the temperature range of 318 - 338 K and pressures up to 20 MPa. Coumarin molar fraction ranged from 3.0x10-3 to 6.0x1
Braz. J. Chem. Eng.. Publicado em: 30/09/2019
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3. An Examination of the Prediction of Hydrate Formation Conditions in the Presence of Thermodynamic Inhibitors
Abstract Gas hydrates are crystalline compounds, solid structures where water traps small guest molecules, typically light gases, in cages formed by hydrogen bonds. They are notorious for causing problems in oil and gas production, transportation and processing. Gas hydrates may form at pressures and temperatures commonly found in natural gas and oil product
Braz. J. Chem. Eng.. Publicado em: 2018-01
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4. Modeling the pull-in instability of the CNT-based probe/actuator under the Coulomb force and the van der Waals attraction
Carbon nano-tube (CNT) is applied to fabricate nano-probes, nano-switches, nano-sensors and nano- actuators. In this paper, a continuum model is employed to obtain the nonlinear constitutive equation and pull-in instability of CNT-based probe/actuators, which includes the effect of electrostatic interaction and intermolecular van der Waals (vdW) forces. The
Lat. Am. j. solids struct.. Publicado em: 2014-12
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5. Determinação de parâmetros de equações de estado para líquidos iônicos a partir de dados de velocidade do som / Determination of parameters of equation of state for ionic liquids through speed of sound data
Os líquidos iônicos são compostos químicos cujas propriedades termofísicas têm sido estudadas a fim de aplicá-los em diversos processos, tais como o de separação. No caso da destilação, para realizar o projeto, otimização e a operacao do sistema, necessita-se conhecer o equilíbrio liquida-vapor, cujo calculo pode ser realizado por equações de
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/06/2012
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6. Estudo de estados estáveis e não estáveis através da termodinâmica dos processos homogêneos em meios contínuos / Study of stable and unstable states using the thermodynamics of homogeneous processes in continuous media
O presente trabalho tem três metas principais: (1) usar as transformações de Levin para estimar coeficientes viriais e avaliar a qualidade das estimativas; (2) inserir adaptações, coerentes com as transformações de Levin, na equação original de van der Waals, de modo a aprimorar sua capacidade de se aproximar de dados experimentais para estados est�
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 24/02/2012
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7. Modelagem de equilíbrio líquido-líquido, líquido-vapor e líquido-líquido-vapor para sistemas binários, ternários, quaternários e pseudo-quaternários, envolvendo a produção de biodiesel / Modeling of liquid-liquid, liquid-vapor and liquid-liquid-vapor equilibria for binary, ternary, quarternay and pseudo-quaternary systems involving biodiesel production
The worldwide energy demand increases every year. This demand will reach levels that cannot be supplied by current conventional fossil fuel resources. In this context, biofuels arise as a growing primary source of energy, raising research opportunities and encouraging technology development. An important technical issue related to biofuels development is the
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 19/01/2012
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8. Cálculo do volume na equação de van der Waals pelo método de cardano
Analytical solutions of a cubic equation with real coefficients are established using the Cardano method. The method is first applied to simple third order equation. Calculation of volume in the van der Waals equation of state is afterwards established. These results are exemplified to calculate the volumes below and above critical temperatures. Analytical a
Química Nova. Publicado em: 2010
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9. Phase equilibria of oleic, palmitic, stearic, linoleic and linolenic acids in supercritical CO2
The knowledge of the phase equilibrium is one of the most important factors to study the design of separation processes controlled by the equilibrium. Fatty acids are present in high concentration as by-products in vegetable oils but the equilibrium data involving these components is scarce. The objective of this work is the experimental determination of the
Brazilian Journal of Chemical Engineering. Publicado em: 2009-03
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10. Supercritical CO2 recovery of caffeine from green coffee oil: new experimental solubility data and modeling
The caffeine solubility in supercritical CO2 was studied by assessing the effects of pressure and temperature on the extraction of green coffee oil (GCO). The Peng-Robinson¹ equation of state was used to correlate the solubility of caffeine with a thermodynamic model and two mixing rules were evaluated: the classical mixing rule of van der Waals with two ad
Química Nova. Publicado em: 2008
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11. Modeling of the liquid-vapor equilibrium in mixtures contend ionic liquids / Modelagem do equilíbrio liquido-vapor em misturas contendo liquidos ionicos
Os líquidos iônicos têm recebido considerável interesse devido a seu potencial como solventes projetados, que podem ser adaptados a vários tipos de processos industriais. A razão principal do interesse nos líquidos iônicos como solventes é sua baixa pressão de vapor, a qual minimiza os riscos de exposição e contaminação ambiental. Esta pesquisa
Publicado em: 2007
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12. Modification of Sako-Wu-Prausnitz equation of state for fluid phase equilibria in polyethylene-ethylene systems at high pressures
In order to model phase equilibria at all pressures, it is necessary to have an equation of state. We have chosen the Sako-Wu-Prausnitz cubic equation of state, which had shown some promising results. However, in order to satisfy our demands, we had to modify it slightly and fit new pure component parameters. New pure component parameters have been determine
Brazilian Journal of Chemical Engineering. Publicado em: 2006-09