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Adrian Bonillapetriciolet - One of the best experts on this subject based on the ideXlab platform.
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unconstrained Gibbs Free Energy minimization for phase equilibrium calculations in nonreactive systems using an improved cuckoo search algorithm
Industrial & Engineering Chemistry Research, 2014Co-Authors: Seifeddeen K Fateen, Adrian BonillapetricioletAbstract:This study introduces a strategy to improve the effectiveness of Cuckoo Search (CS) algorithm for the unconstrained Gibbs Free Energy minimization in phase equilibrium calculations of nonreactive systems. Specifically, the gradient information of the unconstrained Gibbs Free Energy function, which is readily available, is used to enhance the balance between diversification and intensification stages of the CS algorithm for phase-split calculations in multicomponent systems. The results showed that it is feasible to improve the numerical performance of the CS algorithm using the gradient information of the Gibbs Free Energy function; this improved method provides better results for phase equilibrium calculations in nonreactive systems with insignificant additional computational effort. This gradient-based Cuckoo Search (GBCS) algorithm outperformed the conventional CS algorithm, in terms of its reliability and efficiency in solving phase equilibrium problems, especially for multicomponent systems.
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constrained and unconstrained Gibbs Free Energy minimization in reactive systems using genetic algorithm and differential evolution with tabu list
Fluid Phase Equilibria, 2011Co-Authors: Adrian Bonillapetriciolet, G P Rangaiah, Juan Gabriel SegoviahernandezAbstract:Phase equilibrium modeling plays an important role in design, optimization and control of separation processes. The global optimization problem involved in phase equilibrium calculations is very challenging due to the high non-linearity of thermodynamic models especially for multi-component systems subject to chemical reactions. To date, a few attempts have been made in the application of stochastic methods for reactive phase equilibrium calculations compared to those reported for non-reactive systems. In particular, the population-based stochastic methods are known for their good exploration abilities and, when optimal balance between the exploration and exploitation is found, they can be reliable and efficient global optimizers. Genetic algorithms (GAs) and differential evolution with tabu list (DETL) have been very successful for performing phase equilibrium calculations in non-reactive systems. However, there are no previous studies on the performance of both these strategies to solve the Gibbs Free Energy minimization problem for systems subject to chemical equilibrium. In this study, the constrained and unconstrained Gibbs Free Energy minimization in reactive systems have been analyzed and used to assess the performance of GA and DETL. Specifically, the numerical performance of these stochastic methods have been tested using both conventional and transformed composition variables as the decision vector for Free Energy minimization in reactive systems, and their relative strengths are discussed. The results of these strategies are compared with those obtained using SA, which has shown competitive performance in reactive phase equilibrium calculations. To the best of our knowledge, there are no studies in the literature on the comparison of reactive phase equilibrium using both the formulations with stochastic global optimization methods. Our results show that the effectiveness of the stochastic methods tested depends on the stopping criterion, the type of decision variables, and the use of local optimization for intensification stage. Overall, unconstrained Gibbs Free Energy minimization involving transformed composition variables requires more computational time compared to constrained minimization, and DETL has better performance for both constrained and unconstrained Gibbs Free Energy minimization in reactive systems.
Jia-zhen Yang - One of the best experts on this subject based on the ideXlab platform.
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A new theoretical model – The ionic molar surface Gibbs Free Energy and its application
The Journal of Chemical Thermodynamics, 2018Co-Authors: Yi Pan, Yu-xuan Yang, Ning Chang, Zhi Wang, Wei Guan, Jia-zhen YangAbstract:Abstract Three novel ether-functionalized ionic liquids (ILs) 1-ethyl-3-(2-methoxyethyl)-imidazolium acetate, [C22O1IM][OAc], 1-ethyl-3-(2-methoxyethyl)-imidazolium thiocyanate, [C22O1IM][SCN], 1-ethyl-3-(2-methoxyethyl)-imidazolium trifluoromethanesulfonate, [C22O1IM][TfO], and two ILs 1-ethyl-3-(2-methoxyethyl)-imidazolium dicyanamide, [C22O1IM][DCA], 1-ethyl-3-(2-methoxyethyl)-imidazolium bis(trifluoromethylsulfonyl)imide, [C22O1IM][NTF2] were prepared and characterized. Their density and surface tension were measured at T = (298.15–338.15) K. As a new theoretical model, the ionic molar surface Gibbs Free Energy, gi, was put forward. The ionic molar surface Gibbs Free Energy, g−, for [BF4]−, which was as reference ion, was obtained in terms of the extrathermodynamic assumptions so that the ionic molar surface Gibbs Free Energy, g+, of the corresponding cations, [Cnmim]+ (n = 2–6), were determined. In terms of the g+ values of [Cnmim]+ (n = 2–6), the g− values of 12 kinds of anions were determined and then the average g+ value of [C22O1IM]+ (9.52 ± 0.21 kJ·mol−1) was gotten. By using the values of these gi, the predicted values of molar surface Gibbs Free Energy, gest, and surface tension, γest, for [C22O1IM][X] (X = OAC, SCN, DCA, TfO, NTF2) and other 45 ionic liquids were estimated. In comparison, the predicted values correlated quite well with their matching experimental values.
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a new theoretical model the ionic molar surface Gibbs Free Energy and its application
The Journal of Chemical Thermodynamics, 2018Co-Authors: Yi Pan, Yu-xuan Yang, Ning Chang, Zhi Wang, Wei Guan, Jia-zhen YangAbstract:Abstract Three novel ether-functionalized ionic liquids (ILs) 1-ethyl-3-(2-methoxyethyl)-imidazolium acetate, [C22O1IM][OAc], 1-ethyl-3-(2-methoxyethyl)-imidazolium thiocyanate, [C22O1IM][SCN], 1-ethyl-3-(2-methoxyethyl)-imidazolium trifluoromethanesulfonate, [C22O1IM][TfO], and two ILs 1-ethyl-3-(2-methoxyethyl)-imidazolium dicyanamide, [C22O1IM][DCA], 1-ethyl-3-(2-methoxyethyl)-imidazolium bis(trifluoromethylsulfonyl)imide, [C22O1IM][NTF2] were prepared and characterized. Their density and surface tension were measured at T = (298.15–338.15) K. As a new theoretical model, the ionic molar surface Gibbs Free Energy, gi, was put forward. The ionic molar surface Gibbs Free Energy, g−, for [BF4]−, which was as reference ion, was obtained in terms of the extrathermodynamic assumptions so that the ionic molar surface Gibbs Free Energy, g+, of the corresponding cations, [Cnmim]+ (n = 2–6), were determined. In terms of the g+ values of [Cnmim]+ (n = 2–6), the g− values of 12 kinds of anions were determined and then the average g+ value of [C22O1IM]+ (9.52 ± 0.21 kJ·mol−1) was gotten. By using the values of these gi, the predicted values of molar surface Gibbs Free Energy, gest, and surface tension, γest, for [C22O1IM][X] (X = OAC, SCN, DCA, TfO, NTF2) and other 45 ionic liquids were estimated. In comparison, the predicted values correlated quite well with their matching experimental values.
Ole Winther - One of the best experts on this subject based on the ideXlab platform.
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tap Gibbs Free Energy belief propagation and sparsity
Neural Information Processing Systems, 2001Co-Authors: Lehel Csato, Manfred Opper, Ole WintherAbstract:The adaptive TAP Gibbs Free Energy for a general densely connected probabilistic model with quadratic interactions and arbritary single site constraints is derived. We show how a specific sequential minimization of the Free Energy leads to a generalization of Minka's expectation propagation. Lastly, we derive a sparse representation version of the sequential algorithm. The usefulness of the approach is demonstrated on classification and density estimation with Gaussian processes and on an independent component analysis problem.
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NIPS - TAP Gibbs Free Energy, Belief Propagation and Sparsity
2001Co-Authors: Lehel Csato, Manfred Opper, Ole WintherAbstract:The adaptive TAP Gibbs Free Energy for a general densely connected probabilistic model with quadratic interactions and arbritary single site constraints is derived. We show how a specific sequential minimization of the Free Energy leads to a generalization of Minka's expectation propagation. Lastly, we derive a sparse representation version of the sequential algorithm. The usefulness of the approach is demonstrated on classification and density estimation with Gaussian processes and on an independent component analysis problem.
Frank Eckert - One of the best experts on this subject based on the ideXlab platform.
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Brick by brick computation of the Gibbs Free Energy of reaction in solution using quantum chemistry and COSMO‐RS
AIChE Journal, 2017Co-Authors: Arnim Hellweg, Frank EckertAbstract:The computational modeling of reactions is simple in theory but can be quite tricky in practice. This article aims at the purpose of providing an assistance to a proper way of describing reactions theoretically and provides rough guidelines to the computational methods involved. Reactions in liquid phase chemical equilibrium can be described theoretically in terms of the Gibbs Free Energy of reaction. This property can be divided into a sum of three disjunct terms, namely the gas phase reaction Energy, the finite temperature contribution to the Gibbs Free Energy, and the Gibbs Free Energy of solvation. The three contributions to the Gibbs Free Energy of reaction can be computed separately, using different theoretico-chemical calculation methods. While some of these terms can be obtained reliably by computationally cheap methods, for others a high level of theory is required to obtain predictions of quantitative quality. To propose workflows which can strike the balance between accuracy and computational cost, a number of benchmarks assessing the precision of different levels of theory is given. As an illustrative example, the low-temperature hydrogenation reaction of acetaldehyde to ethanol in solvent toluene is shown. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3944–3954, 2017
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Brick by Brick Computation of the Gibbs Free Energy of Reaction in Solution Using Quantum Chemistry and COSMO-RS
arXiv: Chemical Physics, 2016Co-Authors: Arnim Hellweg, Frank EckertAbstract:The computational modelling of reactions is simple in theory but can be quite tricky in practice. This article aims at the purpose of providing an assistance to a proper way of describing reactions theoretically and provides rough guidelines to the computational methods involved. Reactions in liquid phase chemical equilibrium can be described theoretically in terms of the Gibbs Free Energy of reaction. This property can be divided into a sum of three disjunct terms, namely the gas phase reaction Energy, the finite temperature contribution to the Gibbs Free Energy, and the Gibbs Free Energy of solvation. The three contributions to the Gibbs Free Energy of reaction can be computed separately, using different theoretico--chemical calculation methods. While some of these terms can be obtained reliably by computationally cheap methods, for others a high level of theory is required to obtain predictions of quantitative quality. In order to propose workflows which can strike the balance between accuracy and computational cost, a number of benchmarks assessing the precision of different levels of theory is given. As an illustrative example, the low-temperature hydrogenation reaction of acetaldehyde to ethanol in solvent toluene is shown.
Yi Pan - One of the best experts on this subject based on the ideXlab platform.
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A new theoretical model – The ionic molar surface Gibbs Free Energy and its application
The Journal of Chemical Thermodynamics, 2018Co-Authors: Yi Pan, Yu-xuan Yang, Ning Chang, Zhi Wang, Wei Guan, Jia-zhen YangAbstract:Abstract Three novel ether-functionalized ionic liquids (ILs) 1-ethyl-3-(2-methoxyethyl)-imidazolium acetate, [C22O1IM][OAc], 1-ethyl-3-(2-methoxyethyl)-imidazolium thiocyanate, [C22O1IM][SCN], 1-ethyl-3-(2-methoxyethyl)-imidazolium trifluoromethanesulfonate, [C22O1IM][TfO], and two ILs 1-ethyl-3-(2-methoxyethyl)-imidazolium dicyanamide, [C22O1IM][DCA], 1-ethyl-3-(2-methoxyethyl)-imidazolium bis(trifluoromethylsulfonyl)imide, [C22O1IM][NTF2] were prepared and characterized. Their density and surface tension were measured at T = (298.15–338.15) K. As a new theoretical model, the ionic molar surface Gibbs Free Energy, gi, was put forward. The ionic molar surface Gibbs Free Energy, g−, for [BF4]−, which was as reference ion, was obtained in terms of the extrathermodynamic assumptions so that the ionic molar surface Gibbs Free Energy, g+, of the corresponding cations, [Cnmim]+ (n = 2–6), were determined. In terms of the g+ values of [Cnmim]+ (n = 2–6), the g− values of 12 kinds of anions were determined and then the average g+ value of [C22O1IM]+ (9.52 ± 0.21 kJ·mol−1) was gotten. By using the values of these gi, the predicted values of molar surface Gibbs Free Energy, gest, and surface tension, γest, for [C22O1IM][X] (X = OAC, SCN, DCA, TfO, NTF2) and other 45 ionic liquids were estimated. In comparison, the predicted values correlated quite well with their matching experimental values.
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a new theoretical model the ionic molar surface Gibbs Free Energy and its application
The Journal of Chemical Thermodynamics, 2018Co-Authors: Yi Pan, Yu-xuan Yang, Ning Chang, Zhi Wang, Wei Guan, Jia-zhen YangAbstract:Abstract Three novel ether-functionalized ionic liquids (ILs) 1-ethyl-3-(2-methoxyethyl)-imidazolium acetate, [C22O1IM][OAc], 1-ethyl-3-(2-methoxyethyl)-imidazolium thiocyanate, [C22O1IM][SCN], 1-ethyl-3-(2-methoxyethyl)-imidazolium trifluoromethanesulfonate, [C22O1IM][TfO], and two ILs 1-ethyl-3-(2-methoxyethyl)-imidazolium dicyanamide, [C22O1IM][DCA], 1-ethyl-3-(2-methoxyethyl)-imidazolium bis(trifluoromethylsulfonyl)imide, [C22O1IM][NTF2] were prepared and characterized. Their density and surface tension were measured at T = (298.15–338.15) K. As a new theoretical model, the ionic molar surface Gibbs Free Energy, gi, was put forward. The ionic molar surface Gibbs Free Energy, g−, for [BF4]−, which was as reference ion, was obtained in terms of the extrathermodynamic assumptions so that the ionic molar surface Gibbs Free Energy, g+, of the corresponding cations, [Cnmim]+ (n = 2–6), were determined. In terms of the g+ values of [Cnmim]+ (n = 2–6), the g− values of 12 kinds of anions were determined and then the average g+ value of [C22O1IM]+ (9.52 ± 0.21 kJ·mol−1) was gotten. By using the values of these gi, the predicted values of molar surface Gibbs Free Energy, gest, and surface tension, γest, for [C22O1IM][X] (X = OAC, SCN, DCA, TfO, NTF2) and other 45 ionic liquids were estimated. In comparison, the predicted values correlated quite well with their matching experimental values.