A fundamental test of the Higgs Yukawa coupling at RHIC in A+A collisions

Searches for the intermediate boson, $W^{\pm}$, the heavy quantum of the Weak Interaction, via its semi-leptonic decay, $W\to e +\nu$, in the 1970's instead discovered unexpectedly large hadron production at high $p_T$, notably $\pi^0$, which provided a huge background of $e^{\pm}$ from internal and external conversions. Methods developed at the CERN ISR which led to the discovery of direct-single-$e^{\pm}$ in 1974, later determined to be from the semi-leptonic decay of charm which had not yet been discovered, were used by PHENIX at RHIC to make precision measurements of heavy quark production in p-p and Au+Au collisions, leading to the puzzle of apparent equal suppression of light and heavy quarks in the QGP. If the Higgs mechanism gives mass to gauge bosons but not to fermions, then a proposal that all 6 quarks are nearly massless in a QGP, which would resolve the puzzle, can not be excluded. This proposal can be tested with future measurements of heavy quark correlations in A+A collisionsComment: 12 pages, 16 figures, 26th Winter Workshop on Nuclear Dynamics, Ocho Rios, Jamaica WI, January 2-9, 2010. Corrected citation of 1974 direct single lepton discover

Gibbs free energy minimization for the calculation of chemical and phase equilibrium using linear programming

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)One important concern in the calculation of chemical and phase equilibrium using Gibbs free energy minimization is how to guarantee finding the global optimum without depending on an initial guess. This work proposes an approach for the minimization of the Gibbs free energy using linear programming that guaran tees finding the global optimum within some level of precision, for any kind of thermodynamic model. The strategy was used in the calculation of chemical and phase equilibrium involving binary and ternary systems at low and high pressure. The method presented in this proposal is easy to implement, robust and can use several thermodynamic models. (C) 2009 Elsevier B.V. All rights reserved.27841671117128Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Parameter estimation and thermodynamic model fitting for components in mixtures for bio-diesel production

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)In the search of clean, sustainable and renewable energy sources, at present the use of bio-diesel from vegetable oils is one of the possibilities being considered. The knowledge of phase equilibrium in mixtures found in the bio-diesel production is essential for the correct design and operation of the process. However, there is still a lack of information about the parameter values for the models used to describe the phase equilibrium, which could lead to incorrect design of the reactors and the separation processes, and to low efficiency caused by low mass transfer due to the presence of heterogeneous mixtures. In this study, two algorithms are described for the model fitting and parameter estimation, which were used to estimate the values of the parameters in the UNIQUAC and NRTL model for a mixture of vegetable oils and bio-diesel. One of the algorithms uses the Simulated Annealing (SA) method, to find good initial estimates, without any previous knowledge of the parameters. Another algorithm uses Successive Quadratic Programming, using the estimates calculated in the SA algorithm to refine these estimates. In both algorithms, the criterion for fitting is the minimization of the square of the difference between calculated and experimental values. In both algorithms, the equilibrium is calculated using the direct global minimization of the Gibbs free energy with respect to the number of moles of each component, at constant T and P, for a given set of model parameters. The results obtained were able to correctly reproduce the experimental values of phase equilibrium composition.143435442Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Simultaneous calculation of chemical and phase equilibria using convexity analysis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Chemical and phase equilibria were considered for closed multicomponent reactive systems at: (a) constant pressure and temperature; (b) constant pressure and enthalpy. Equilibrium at constant P and T was found by minimization of G, while equilibrium at constant P and H was found by maximization of S or minimization of -S, all with respect to the number of moles of each component in each phase. Both cases could be handled as optimization problems, satisfying the restrictions imposed by mole or atom balances, and non-negativity of number of moles. Convexity analyses were carried out, and the conditions were found in order to guarantee global minimum, for one liquid phase, one gas phase, and a number of solid phases. The minimum point was then found either by analytical methods or by direct minimization methods. These strategies were tested for a number of cases, with good results. (c) 2010 Elsevier Ltd. All rights reserved.35712261237Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Thermodynamic analysis of steam reforming of ethanol and glycerine for hydrogen production

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)In the past few years there has been a growing interest in environmentally clean renewable sources for hydrogen production. in this context new technologies have been developed for ethanol and glycerine reforming. Hydrogen production varies significantly according to the operating conditions such as pressure, temperature and feed reactants ratio. The thermodynamic analysis provides important knowledge about the effects of those variables on the process of ethanol and glycerine reforming. The present work was aimed at analyzing the thermodynamic steam reforming of ethanol and glycerine, using Gibbs free energy minimization using actual temperature and pressure data found in the literature. The nonlinear programming model was implemented in GAMS (R) and the CONOPT2 solver was used to solve the equations. The ideality in gaseous phase and the formation of solid carbon was considered. The methodology used reproduced the most relevant papers involving experimental studies and thermodynamic analysis. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.341323332Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)FINEPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Thermodynamic analysis of supercritical water gasification of methanol, ethanol, glycerol, glucose and cellulose

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)In the present work the Gibbs free energy minimization, using a non-linear programming formulation and an approximation in the gas fugacities, was used to calculate the equilibrium composition for supercritical water gasification of methanol, ethanol, glycerol, glucose and cellulose. The proposed formulation mathematically ensures finding the global optimal solution with no need of an initial estimate and the numerical results are close to the ones calculated using non-ideal gas formulation. Therefore, the proposed approach is reliable and easy to use, without numerical difficulties, such as an undesirable local minimum. The model predictions show a good agreement with the experimental studies in all cases studied in this work. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.342497379744FINEPFundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [142741/2008-6, 140933/2008-5

Thermodynamic analysis of fatty acid esterification for fatty acid alkyl esters production

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The development of renewable energy source alternatives has become a planet need because of the unavoidable fossil fuel scarcity and for that reason biodiesel production has attracted growing interest over the last decade. The reaction yield for obtaining fatty acid alkyl esters varies significantly according to the operating conditions such as temperature and the feed reactants ratio and thus investigation of the thermodynamics involved in such reactional systems may afford important knowledge on the effects of process variables on biodiesel production. The present work reports a thermodynamic analysis of fatty acid esterification reaction at low pressure. For this purpose, Gibbs free energy minimization was employed with UNIFAC and modified Wilson thermodynamic models through a nonlinear programming model implementation. The methodology employed is shown to reproduce the most relevant investigations involving experimental studies and thermodynamic analysis. (C) 2010 Elsevier Ltd. All rights reserved.352781788Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [142741/2008-6, 140933/2008-5