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An efficient numerical method for solving a model describing crystallization of polymorphs / Shamsul Qamar in Industrial & engineering chemistry research, Vol. 49 N° 10 (Mai 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 10 (Mai 2010) . - pp. 4940–4947 Titre : An efficient numerical method for solving a model describing crystallization of polymorphs Type de document : texte imprimé Auteurs : Shamsul Qamar, Auteur ; Saima Noor, Auteur ; Andreas Seidel - Morgenstern, Auteur Année de publication : 2010 Article en page(s) : pp. 4940–4947 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Crystallization  Polymorphs Résumé : Polymorphism, in which a chemical compound exhibits different crystal forms or structures, has significant influence on the processing and storage of some crystalline powders in pharmaceutical industry. Different crystal structures, the so-called polymorphs, have different physical and chemical properties, such as crystal morphology, solubility, and color. These properties can have profound effect on the performance of products. This fact has motivated several researchers in this field to analyze, simulate, and control the crystallization of polymorphs. In this article, an efficient and accurate numerical method is introduced for solving a model describing crystallization of polymorphs. The proposed method has two parts. In the first part, a coupled system of ordinary differential equations of moments and the solute concentration is numerically solved in the time domain of interest. The resulting values are used to get the discrete growth and nucleation rates in the same time domain. In the second part, these discrete values along with the initial crystal size distribution (CSD) are used to construct the final CSD. The method is applied to a model describing crystallization of polymorphs of l-glutamic acid. For a validation, the results of the proposed technique are compared with those from the finite volume schemes. The numerical results demonstrate the potential of our scheme for the simulation of current model with high efficiency and accuracy. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018353 [article] An efficient numerical method for solving a model describing crystallization of polymorphs [texte imprimé] / Shamsul Qamar, Auteur ; Saima Noor, Auteur ; Andreas Seidel - Morgenstern, Auteur . - 2010 . - pp. 4940–4947. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 10 (Mai 2010) . - pp. 4940–4947 Mots-clés : Crystallization  Polymorphs Résumé : Polymorphism, in which a chemical compound exhibits different crystal forms or structures, has significant influence on the processing and storage of some crystalline powders in pharmaceutical industry. Different crystal structures, the so-called polymorphs, have different physical and chemical properties, such as crystal morphology, solubility, and color. These properties can have profound effect on the performance of products. This fact has motivated several researchers in this field to analyze, simulate, and control the crystallization of polymorphs. In this article, an efficient and accurate numerical method is introduced for solving a model describing crystallization of polymorphs. The proposed method has two parts. In the first part, a coupled system of ordinary differential equations of moments and the solute concentration is numerically solved in the time domain of interest. The resulting values are used to get the discrete growth and nucleation rates in the same time domain. In the second part, these discrete values along with the initial crystal size distribution (CSD) are used to construct the final CSD. The method is applied to a model describing crystallization of polymorphs of l-glutamic acid. For a validation, the results of the proposed technique are compared with those from the finite volume schemes. The numerical results demonstrate the potential of our scheme for the simulation of current model with high efficiency and accuracy. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9018353

Application of discontinuous galerkin scheme to batch crystallization models / Shamsul Qamar in Industrial & engineering chemistry research, Vol. 50 N° 7 (Avril 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp. 4113-4122 Titre : Application of discontinuous galerkin scheme to batch crystallization models Type de document : texte imprimé Auteurs : Shamsul Qamar, Auteur ; Iltaf Hussain, Auteur ; Andreas Seidel - Morgenstern, Auteur Année de publication : 2011 Article en page(s) : pp. 4113-4122 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling  Crystallization  Batchwise Résumé : A discontinuous Galerkin finite element method is proposed for solving batch crystallization models. The suggested method has the capability of capturing sharp discontinuities and narrow peaks of the crystal size distribution (CSD). The accuracy of the method can be improved by introducing additional nodes in the same solution element and, hence, avoids the expansion of mesh stencils which is normally observed in the high order finite volume schemes. For that reason, the method can be easily applied up to boundary cells without losing accuracy. The method is robust and well suited for large-scale time-dependent computations in which a high degree of accuracy is demanded. Several test cases are carried out in this paper. The numerical results verify the efficiency and accuracy of the proposed method. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24027659 [article] Application of discontinuous galerkin scheme to batch crystallization models [texte imprimé] / Shamsul Qamar, Auteur ; Iltaf Hussain, Auteur ; Andreas Seidel - Morgenstern, Auteur . - 2011 . - pp. 4113-4122. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp. 4113-4122 Mots-clés : Modeling  Crystallization  Batchwise Résumé : A discontinuous Galerkin finite element method is proposed for solving batch crystallization models. The suggested method has the capability of capturing sharp discontinuities and narrow peaks of the crystal size distribution (CSD). The accuracy of the method can be improved by introducing additional nodes in the same solution element and, hence, avoids the expansion of mesh stencils which is normally observed in the high order finite volume schemes. For that reason, the method can be easily applied up to boundary cells without losing accuracy. The method is robust and well suited for large-scale time-dependent computations in which a high degree of accuracy is demanded. Several test cases are carried out in this paper. The numerical results verify the efficiency and accuracy of the proposed method. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24027659