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Design of optimal and near-optimal enterprise-wide supply networks for multiple products in the process industry / L. T. Fan in Industrial & engineering chemistry research, Vol. 48 N°4 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2003–2008 Titre : Design of optimal and near-optimal enterprise-wide supply networks for multiple products in the process industry Type de document : texte imprimé Auteurs : L. T. Fan, Auteur ; Young Kim, Auteur ; Choamun Yun, Auteur Année de publication : 2009 Article en page(s) : p. 2003–2008 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Optimal  enterprise-wide  networks  Feedstocks  Graph-theoretic  method  Mixed  integer  linear  programming  problem Résumé : The optimal and near-optimal enterprise-wide networks are designed, that is synthesized, for supplying feedstocks and distributing multiple products manufactured from these feedstocks in the process industry by resorting to the graph-theoretic method based on process graphs (P-graphs). Such feedstocks and products, conveyed through supply networks, are invariably materials for which the law of mass conservation is universally valid. Moreover, any of the actions applied to or exerted on a given feedstock or product, transiting through the supply networks, will induce a change in at least one of its attributes, thereby transforming the feedstock or product. Examples of the actions are loading, blending, pumping, tracking, unloading, subdividing, and/or wrapping; and those of the attributes are chemical composition, physical state, flow characteristics, external appearance, and/or location. Thus, in the broadest sense, any supply network can be regarded as a process network. The feedstocks and the products manufactured from them serve as the raw materials for and the products from the supply network at its entrance and exit, respectively. An operating, that is functional, unit can be unequivocally identified where any action is exerted on these raw materials or products. Naturally, the networks can be represented graph-theoretically as P-graphs. The proposed method is illustrated with an example involving three process plants, three markets, and three products under the three scenarios of coordination, cooperation, and competition. It has given rise simultaneously to the optimal as well as near-optimal supply networks in the ranked order. The example, formulated as the mixed integer linear programming problem, yields the same optimal solutions only, but not the near-optimal solutions in the ranked order. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800447g [article] Design of optimal and near-optimal enterprise-wide supply networks for multiple products in the process industry [texte imprimé] / L. T. Fan, Auteur ; Young Kim, Auteur ; Choamun Yun, Auteur . - 2009 . - p. 2003–2008. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2003–2008 Mots-clés : Optimal  enterprise-wide  networks  Feedstocks  Graph-theoretic  method  Mixed  integer  linear  programming  problem Résumé : The optimal and near-optimal enterprise-wide networks are designed, that is synthesized, for supplying feedstocks and distributing multiple products manufactured from these feedstocks in the process industry by resorting to the graph-theoretic method based on process graphs (P-graphs). Such feedstocks and products, conveyed through supply networks, are invariably materials for which the law of mass conservation is universally valid. Moreover, any of the actions applied to or exerted on a given feedstock or product, transiting through the supply networks, will induce a change in at least one of its attributes, thereby transforming the feedstock or product. Examples of the actions are loading, blending, pumping, tracking, unloading, subdividing, and/or wrapping; and those of the attributes are chemical composition, physical state, flow characteristics, external appearance, and/or location. Thus, in the broadest sense, any supply network can be regarded as a process network. The feedstocks and the products manufactured from them serve as the raw materials for and the products from the supply network at its entrance and exit, respectively. An operating, that is functional, unit can be unequivocally identified where any action is exerted on these raw materials or products. Naturally, the networks can be represented graph-theoretically as P-graphs. The proposed method is illustrated with an example involving three process plants, three markets, and three products under the three scenarios of coordination, cooperation, and competition. It has given rise simultaneously to the optimal as well as near-optimal supply networks in the ranked order. The example, formulated as the mixed integer linear programming problem, yields the same optimal solutions only, but not the near-optimal solutions in the ranked order. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800447g

Stochastic modeling for the formation of activated carbons / L. T. Fan in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8836–8841 Titre : Stochastic modeling for the formation of activated carbons : nonlinear approach Type de document : texte imprimé Auteurs : L. T. Fan, Auteur ; Andres Argoti, Auteur Année de publication : 2011 Article en page(s) : pp. 8836–8841 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Activated  carbons Résumé : Activated carbons (ACs) have been widely deployed in the purification of gases and liquids or the separation of their mixtures. The formation of ACs entails the modification of the original internal surfaces of carbonaceous substrates, for example, coal or biomass, which can be effected by a variety of chemical or physical methods, thereby augmenting the carbonaceous substrates’ adsorbing capacities. The formation of ACs tends to proceed randomly or stochastically in view of the discrete and mesoscopic nature of the carbonaceous substrates, as well as the random encounters between the activation agent and carbon on the carbonaceous substrates’ internal surfaces; in addition, the carbonaceous substrates’ internal surfaces exhibit an intricate morphology or structure. Naturally, these traits of the formation of ACs render the process to vary incessantly with time. Thus, it is highly desirable that the analysis, modeling, and simulation of the formation of ACs from carbonaceous substrates be performed in light of a stochastic paradigm. Herein, a stochastic model for the formation of ACs is formulated as a pure-death process based on a nonlinear intensity of transition. The model gives rise to the process’ nonlinear master equation whose solution is obtained by resorting to a rational approximation method, the system-size expansion. This solution renders it possible to compute the mean as well as higher moments about this mean, for example, variance or standard deviation, which reveal and quantify the process’ inherent fluctuations. The results of modeling are validated by comparing them with the available experimental data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102247z [article] Stochastic modeling for the formation of activated carbons : nonlinear approach [texte imprimé] / L. T. Fan, Auteur ; Andres Argoti, Auteur . - 2011 . - pp. 8836–8841. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8836–8841 Mots-clés : Activated  carbons Résumé : Activated carbons (ACs) have been widely deployed in the purification of gases and liquids or the separation of their mixtures. The formation of ACs entails the modification of the original internal surfaces of carbonaceous substrates, for example, coal or biomass, which can be effected by a variety of chemical or physical methods, thereby augmenting the carbonaceous substrates’ adsorbing capacities. The formation of ACs tends to proceed randomly or stochastically in view of the discrete and mesoscopic nature of the carbonaceous substrates, as well as the random encounters between the activation agent and carbon on the carbonaceous substrates’ internal surfaces; in addition, the carbonaceous substrates’ internal surfaces exhibit an intricate morphology or structure. Naturally, these traits of the formation of ACs render the process to vary incessantly with time. Thus, it is highly desirable that the analysis, modeling, and simulation of the formation of ACs from carbonaceous substrates be performed in light of a stochastic paradigm. Herein, a stochastic model for the formation of ACs is formulated as a pure-death process based on a nonlinear intensity of transition. The model gives rise to the process’ nonlinear master equation whose solution is obtained by resorting to a rational approximation method, the system-size expansion. This solution renders it possible to compute the mean as well as higher moments about this mean, for example, variance or standard deviation, which reveal and quantify the process’ inherent fluctuations. The results of modeling are validated by comparing them with the available experimental data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102247z