Documents disponibles écrits par cet auteur

Direct Chlorination of Nickel-Containing Materials. Recovery of the Metal from Different Sources / J. F. Álvarez in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8184–8191 Titre : Direct Chlorination of Nickel-Containing Materials. Recovery of the Metal from Different Sources Type de document : texte imprimé Auteurs : J. F. Álvarez, Auteur ; Ana E. Bohé, Auteur Année de publication : 2008 Article en page(s) : p. 8184–8191 Note générale : chemical engineering Langues : Anglais (eng) Mots-clés : Chlorination  of  nickel Résumé : In the present work, the chlorination of nickel-containing materials is proposed: using NiO and mixtures that simulate the conditions of 12 wt % NiO−Al2O3 catalyst, prepared by mechanical mixing and incipient wetness impregnation (IWI), the reaction with gaseous chlorine proceeds from 500 to 800 °C. Non-isothermal experiments from 20 to 950 °C and isothermal measurements at 725, 800, and 850 °C were performed under Ar−Cl2 atmosphere in a thermogravimetric (TG) system. Direct chlorination of the mixtures was carried out isothermally in a tubular reactor under a flow of Cl2 from 500 to 800 °C. The chlorination started at 725, 473, and 428 °C for NiO, the mechanical mixture, and the IWI mixture, respectively. The high temperature for NiO can be explained by its BET area, which is small enough to reduce the reactivity of the sample. The recovery factor of Ni from Al2O3 attained at 800 °C was 85% for the mechanical mixture and 96% for the IWI mixture. All the species were characterized by X-ray diffraction (XRD), scanning-electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) techniques. They were quantified by X-ray fluorescence spectrometry (XRF), and BET surface area (BET) was measured in the samples. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006598 [article] Direct Chlorination of Nickel-Containing Materials. Recovery of the Metal from Different Sources [texte imprimé] / J. F. Álvarez, Auteur ; Ana E. Bohé, Auteur . - 2008 . - p. 8184–8191. chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8184–8191 Mots-clés : Chlorination  of  nickel Résumé : In the present work, the chlorination of nickel-containing materials is proposed: using NiO and mixtures that simulate the conditions of 12 wt % NiO−Al2O3 catalyst, prepared by mechanical mixing and incipient wetness impregnation (IWI), the reaction with gaseous chlorine proceeds from 500 to 800 °C. Non-isothermal experiments from 20 to 950 °C and isothermal measurements at 725, 800, and 850 °C were performed under Ar−Cl2 atmosphere in a thermogravimetric (TG) system. Direct chlorination of the mixtures was carried out isothermally in a tubular reactor under a flow of Cl2 from 500 to 800 °C. The chlorination started at 725, 473, and 428 °C for NiO, the mechanical mixture, and the IWI mixture, respectively. The high temperature for NiO can be explained by its BET area, which is small enough to reduce the reactivity of the sample. The recovery factor of Ni from Al2O3 attained at 800 °C was 85% for the mechanical mixture and 96% for the IWI mixture. All the species were characterized by X-ray diffraction (XRD), scanning-electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) techniques. They were quantified by X-ray fluorescence spectrometry (XRF), and BET surface area (BET) was measured in the samples. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006598

Mathematical expressions for the transit time of merchandise through a liner shipping network / J. F. Álvarez in Journal of the operational research society (JORS), Vol. 63 N° 6 (Juin 2012) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 63 N° 6 (Juin 2012) . - pp. 709–714 Titre : Mathematical expressions for the transit time of merchandise through a liner shipping network Type de document : texte imprimé Auteurs : J. F. Álvarez, Auteur Année de publication : 2012 Article en page(s) : pp. 709–714 Note générale : Operational research Langues : Anglais (eng) Mots-clés : Sea  transport  Logistics  Integer  programming  Level  of  service Index. décimale : 001.424 Résumé : Recent publications on the design of liner shipping networks are limited in their treatment of the level of service (LoS) experienced by shippers. We propose the use of inventory holding costs—a function of merchandise transit time—as a proxy for LoS. We assume the existence of a two-tier optimization model, where fleet deployment, vessel routing, and vessel speed are determined in the higher tier. Merchandise flows and transshipment quantities are determined in the lower tier. We partition the total merchandise transit time into time spent in open waters, time spent during port calls, and time spent dwelling in the terminal yard. Using the notions of service frequency and service phase, we develop mathematical expressions for the three aforementioned quantities within the lower tier of the optimization model. We arrive at a bilinear expression for overall inventory holding costs that is suitable for liner shipping network design. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n6/abs/jors201172a.html [article] Mathematical expressions for the transit time of merchandise through a liner shipping network [texte imprimé] / J. F. Álvarez, Auteur . - 2012 . - pp. 709–714. Operational research Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 63 N° 6 (Juin 2012) . - pp. 709–714 Mots-clés : Sea  transport  Logistics  Integer  programming  Level  of  service Index. décimale : 001.424 Résumé : Recent publications on the design of liner shipping networks are limited in their treatment of the level of service (LoS) experienced by shippers. We propose the use of inventory holding costs—a function of merchandise transit time—as a proxy for LoS. We assume the existence of a two-tier optimization model, where fleet deployment, vessel routing, and vessel speed are determined in the higher tier. Merchandise flows and transshipment quantities are determined in the lower tier. We partition the total merchandise transit time into time spent in open waters, time spent during port calls, and time spent dwelling in the terminal yard. Using the notions of service frequency and service phase, we develop mathematical expressions for the three aforementioned quantities within the lower tier of the optimization model. We arrive at a bilinear expression for overall inventory holding costs that is suitable for liner shipping network design. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n6/abs/jors201172a.html