Documents disponibles écrits par cet auteur

Fast compartmental monte carlo simulation of population balance models / Roberto Irizarry in Industrial & engineering chemistry research, Vol. 51 N° 47 (Novembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 47 (Novembre 2012) . - pp. 15484–15496 Titre : Fast compartmental monte carlo simulation of population balance models : Application to Nanoparticle formation in nonhomogeneous conditions Type de document : texte imprimé Auteurs : Roberto Irizarry, Auteur Année de publication : 2013 Article en page(s) : pp. 15484–15496 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanoparticle Résumé : A new compartmental Monte Carlo (CMC) algorithm is introduced for the stochastic simulation of population balance models in spatially heterogeneous systems. The heterogeneities are modeled using a network of compartments. The algorithm is based on a new stochastic procedure called particle bundle flow (PBF) to model the stochastic transfer of particles between compartments in a given time interval (a time-driven algorithm). Different from other time-driven methods, the accuracy of the PBF is independent of the particle concentration. The validity of the PBF method is demonstrated by construction and confirmed with numerical experiments. A new strategy for time step control is developed to set bounds on the calculation of the time steps during the simulation. The CMC algorithm, based on the combination of the PBF algorithm with the τ point ensemble Monte Carlo algorithm, is a general-purpose methodology that can be applied to any network of compartments. The computational speed and the low computational load of this algorithm allow the solution of problems that may be intractable otherwise. A new hybrid strategy for the solution of problems with stochastic fluctuations and disparate time scales is also developed in this work. The CMC is applied to study the formation of nanoparticles in a large reactor utilizing a two-compartment model. The Monte Carlo ability to track single events is utilized to study the impact of turbulence and the stability factor on the generation of large particles. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3011116 [article] Fast compartmental monte carlo simulation of population balance models : Application to Nanoparticle formation in nonhomogeneous conditions [texte imprimé] / Roberto Irizarry, Auteur . - 2013 . - pp. 15484–15496. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 47 (Novembre 2012) . - pp. 15484–15496 Mots-clés : Nanoparticle Résumé : A new compartmental Monte Carlo (CMC) algorithm is introduced for the stochastic simulation of population balance models in spatially heterogeneous systems. The heterogeneities are modeled using a network of compartments. The algorithm is based on a new stochastic procedure called particle bundle flow (PBF) to model the stochastic transfer of particles between compartments in a given time interval (a time-driven algorithm). Different from other time-driven methods, the accuracy of the PBF is independent of the particle concentration. The validity of the PBF method is demonstrated by construction and confirmed with numerical experiments. A new strategy for time step control is developed to set bounds on the calculation of the time steps during the simulation. The CMC algorithm, based on the combination of the PBF algorithm with the τ point ensemble Monte Carlo algorithm, is a general-purpose methodology that can be applied to any network of compartments. The computational speed and the low computational load of this algorithm allow the solution of problems that may be intractable otherwise. A new hybrid strategy for the solution of problems with stochastic fluctuations and disparate time scales is also developed in this work. The CMC is applied to study the formation of nanoparticles in a large reactor utilizing a two-compartment model. The Monte Carlo ability to track single events is utilized to study the impact of turbulence and the stability factor on the generation of large particles. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3011116

Preparation and formation mechanism of silver particles with spherical open structures / Roberto Irizarry in Industrial & engineering chemistry research, Vol. 50 N° 13 (Juillet 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 8023-8033 Titre : Preparation and formation mechanism of silver particles with spherical open structures Type de document : texte imprimé Auteurs : Roberto Irizarry, Auteur ; Lourian Burwell, Auteur ; Madeline S. Leon-Velazquez, Auteur Année de publication : 2011 Article en page(s) : pp. 8023-8033 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Formation  mechanism  Preparation Résumé : A new type of highly dispersible silver particles has been developed consisting of two- and three-dimensional building blocks that form spherical shapes with open structures. The first morphology consists of uniform particles that are composed of anisotropic building blocks mainly in the form of a network of platelets forming a spherical, open-structured particle. These platelets are 100-2000 nm in length, with a crystallite size in the range 20-100 nm. The second morphology consists of isotropic components that are 100-500 nm in length, with a crystallite size in the range of 20-100 nm. In both cases, the silver powder was comprised of well-defined monosized particles and was highly dispersible. These powders were prepared by rapidly mixing a silver solution with an ascorbic acid/sodium citrate solution at low pH. A mechanism is proposed for the formation of these novel structures. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332127 [article] Preparation and formation mechanism of silver particles with spherical open structures [texte imprimé] / Roberto Irizarry, Auteur ; Lourian Burwell, Auteur ; Madeline S. Leon-Velazquez, Auteur . - 2011 . - pp. 8023-8033. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 8023-8033 Mots-clés : Formation  mechanism  Preparation Résumé : A new type of highly dispersible silver particles has been developed consisting of two- and three-dimensional building blocks that form spherical shapes with open structures. The first morphology consists of uniform particles that are composed of anisotropic building blocks mainly in the form of a network of platelets forming a spherical, open-structured particle. These platelets are 100-2000 nm in length, with a crystallite size in the range 20-100 nm. The second morphology consists of isotropic components that are 100-500 nm in length, with a crystallite size in the range of 20-100 nm. In both cases, the silver powder was comprised of well-defined monosized particles and was highly dispersible. These powders were prepared by rapidly mixing a silver solution with an ascorbic acid/sodium citrate solution at low pH. A mechanism is proposed for the formation of these novel structures. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332127

Simulated dynamic optical response strategy for model identification of metal colloid synthesis / Roberto Irizarry in Industrial & engineering chemistry research, Vol. 49 N° 12 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5588–5602 Titre : Simulated dynamic optical response strategy for model identification of metal colloid synthesis Type de document : texte imprimé Auteurs : Roberto Irizarry, Auteur Année de publication : 2010 Article en page(s) : pp. 5588–5602 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Metal  spherical  particle  formation  Optical  kinetic  data  Metal  colloid  synthesis Résumé : A model for metal spherical particle formation is proposed, guided by optical kinetic data of monodisperse metal colloid synthesis. The dynamic optical response of these systems is characterized by broad bands, making their analysis difficult to interpret in terms of particles sizes. To overcome this problem, the data are analyzed in terms of a new strategy called simulated dynamic optical response. Kinetic data were generated using a silver-ethylenediamine complex reduced with isoascorbic acid as a model system. Using this strategy, it was found that autocatalytic formation of primary particles followed by a zone of very fast aggregation mechanism can describe the dominant dynamics during early stages. In later stages, the dominant mechanism switches to slower aggregation modulated by a stability factor. The presented model and identification strategy may be applied to other reaction precipitation systems to produce metal particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100644h [article] Simulated dynamic optical response strategy for model identification of metal colloid synthesis [texte imprimé] / Roberto Irizarry, Auteur . - 2010 . - pp. 5588–5602. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5588–5602 Mots-clés : Metal  spherical  particle  formation  Optical  kinetic  data  Metal  colloid  synthesis Résumé : A model for metal spherical particle formation is proposed, guided by optical kinetic data of monodisperse metal colloid synthesis. The dynamic optical response of these systems is characterized by broad bands, making their analysis difficult to interpret in terms of particles sizes. To overcome this problem, the data are analyzed in terms of a new strategy called simulated dynamic optical response. Kinetic data were generated using a silver-ethylenediamine complex reduced with isoascorbic acid as a model system. Using this strategy, it was found that autocatalytic formation of primary particles followed by a zone of very fast aggregation mechanism can describe the dominant dynamics during early stages. In later stages, the dominant mechanism switches to slower aggregation modulated by a stability factor. The presented model and identification strategy may be applied to other reaction precipitation systems to produce metal particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100644h