Nos Abonnements
Ressources Électroniques
|
[n° ou bulletin]
[n° ou bulletin]
Vol. 50 N° 23 - Décembre 2011 [texte imprimé] . - 2012 . - p. 12845-13588 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
|
Exemplaires
| Code-barres | Cote | Support | Localisation | Section | Disponibilité |
|---|---|---|---|---|---|
| aucun exemplaire | |||||
|
Dépouillements
Ajouter le résultat dans votre panierKinetic mechanisms of cholesterol synthesis / Tapobrata Panda in Industrial & engineering chemistry research, Vol. 50 N° 23 (Décembre 2011)
Titre : Kinetic mechanisms of cholesterol synthesis : a review Type de document : texte imprimé Auteurs : Tapobrata Panda, Auteur ; Tanmay Basak, Auteur ; Ganesan Saraswathi, Auteur Année de publication : 2012 Article en page(s) : pp. 12847-12864 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Résumé : Increased levels of cholesterol lead to critical health risk factors such as hypercholesterolemia and atherosclerosis in the human system. Regulation of cholesterol synthesis in mammals, especially in humans, is required for a healthy lifestyle. Cholesterol synthesis from acetyl Co-A in liver involves more than 10 enzymes, beginning with acetoacetyl Co-A thiolase, to desmosterol reductase. Among these, 3-hydroxy-3-methylglutaryl-Coenzyme A reductase (HMGR) could be involved in the rate-determining step of cholesterol synthesis. Statins are used to control HMGR. Because statins possess many side effects, an alternate drug for hypercholesterolemia with minimum or no side effects is in great demand. The first and foremost step in drug design is to select a suitable drug target, most likely an enzyme inhibitor. In this regard, an in-depth study of the kinetics of the enzymes involved in cholesterol synthesis is required for a preferred drug target, which, in turn, requires a thorough knowledge of the mechanisms involved in each step of cholesterol synthesis. This communication gives an overview of the mechanisms and kinetics of the key enzymatic reactions involved in the cholesterol synthesis pathway in different organisms. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267443
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12847-12864[article] Kinetic mechanisms of cholesterol synthesis : a review [texte imprimé] / Tapobrata Panda, Auteur ; Tanmay Basak, Auteur ; Ganesan Saraswathi, Auteur . - 2012 . - pp. 12847-12864.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12847-12864
Mots-clés : Kinetics Résumé : Increased levels of cholesterol lead to critical health risk factors such as hypercholesterolemia and atherosclerosis in the human system. Regulation of cholesterol synthesis in mammals, especially in humans, is required for a healthy lifestyle. Cholesterol synthesis from acetyl Co-A in liver involves more than 10 enzymes, beginning with acetoacetyl Co-A thiolase, to desmosterol reductase. Among these, 3-hydroxy-3-methylglutaryl-Coenzyme A reductase (HMGR) could be involved in the rate-determining step of cholesterol synthesis. Statins are used to control HMGR. Because statins possess many side effects, an alternate drug for hypercholesterolemia with minimum or no side effects is in great demand. The first and foremost step in drug design is to select a suitable drug target, most likely an enzyme inhibitor. In this regard, an in-depth study of the kinetics of the enzymes involved in cholesterol synthesis is required for a preferred drug target, which, in turn, requires a thorough knowledge of the mechanisms involved in each step of cholesterol synthesis. This communication gives an overview of the mechanisms and kinetics of the key enzymatic reactions involved in the cholesterol synthesis pathway in different organisms. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267443 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Evaluation of the effect of the concentration of CO2 on the overall reactivity of drop tube furnace derived indian sub - bituminous coal chars during CO2/O2 combustion Type de document : texte imprimé Auteurs : V. Saravanan, Auteur ; R. Shivakumar, Auteur ; Jayanti, S., Auteur Année de publication : 2012 Article en page(s) : pp. 12865–12871 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nonisothermal Thermogravimetric Derived Résumé : A nonisothermal thermogravimetric analysis technique was used to evaluate the effect of CO2 concentration on the overall reactivity of Indian coal chars during CO2/O2 combustion. The study was carried out for the drop tube furnace derived chars of three Indian sub-bituminous coals from different sources. The selected coal char samples were combusted in different CO2/O2 molar volume combinations, namely, 80:20, 60:40, 40:60, 20:80, and 0:100 (pure O2) so that the effect of the concentration of CO2 on the overall reaction rate could be quantified. The Arrhenius constants (E and A) were determined using the random pore model. The concept of weighted mean activation energy was used to account for the multi-Arrhenius linearities. Empirical equations were proposed to evaluate the Arrhenius constants in terms of the mole fraction of CO2 for the overall reaction rate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1019358
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12865–12871[article] Evaluation of the effect of the concentration of CO2 on the overall reactivity of drop tube furnace derived indian sub - bituminous coal chars during CO2/O2 combustion [texte imprimé] / V. Saravanan, Auteur ; R. Shivakumar, Auteur ; Jayanti, S., Auteur . - 2012 . - pp. 12865–12871.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12865–12871
Mots-clés : Nonisothermal Thermogravimetric Derived Résumé : A nonisothermal thermogravimetric analysis technique was used to evaluate the effect of CO2 concentration on the overall reactivity of Indian coal chars during CO2/O2 combustion. The study was carried out for the drop tube furnace derived chars of three Indian sub-bituminous coals from different sources. The selected coal char samples were combusted in different CO2/O2 molar volume combinations, namely, 80:20, 60:40, 40:60, 20:80, and 0:100 (pure O2) so that the effect of the concentration of CO2 on the overall reaction rate could be quantified. The Arrhenius constants (E and A) were determined using the random pore model. The concept of weighted mean activation energy was used to account for the multi-Arrhenius linearities. Empirical equations were proposed to evaluate the Arrhenius constants in terms of the mole fraction of CO2 for the overall reaction rate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1019358 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Modeling the cytotoxicity of cisplatin Type de document : texte imprimé Auteurs : Vishnu Sresht, Auteur ; Jayesh R. Bellare, Auteur ; Santosh K. Gupta, Auteur Année de publication : 2012 Article en page(s) : pp. 12872–12880 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cytotoxicity Cisplatin Résumé : Cisplatin has been the mainstay of chemotherapeutic efforts against several types of cancers for over 30 years. However, there is still much that is unknown regarding its mechanism of action. The several serious side effects of cisplatin therapy and the lack of consensus regarding the ideal dosage regimen necessitate the development of a quantitative model for cisplatin action. A first-level mathematical model is presented for the cytotoxicity of cisplatin which predicts the survival of cancer cells when subjected to a given dose of this antitumor drug. This model comprises of (i) an uptake model that describes the movement of cisplatin molecules from the extracellular medium to the cell nucleus and the formation (and repair) of cisplatin−DNA adducts and (ii) a tolerance model that relates the quantity of cisplatin−DNA adducts formed inside the cell nuclei in a tumor to the fraction of tumor cells that are killed. The predictions of the model are in good agreement with in vitro experimental data obtained for carcinoma cell lines. To the best of our knowledge, this is the first model combining the uptake of cisplatin (consistent with the biochemical mechanism of action) with cell death (based on cisplatin−DNA adducts). It predicts a Pareto-type set of dosage regimen (dosage, Cext, vs exposure time, texp) of cisplatin to obtain a desired chemotherapeutic efficacy. Some reported patient-data is consistent with this prediction DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102360e
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12872–12880[article] Modeling the cytotoxicity of cisplatin [texte imprimé] / Vishnu Sresht, Auteur ; Jayesh R. Bellare, Auteur ; Santosh K. Gupta, Auteur . - 2012 . - pp. 12872–12880.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12872–12880
Mots-clés : Cytotoxicity Cisplatin Résumé : Cisplatin has been the mainstay of chemotherapeutic efforts against several types of cancers for over 30 years. However, there is still much that is unknown regarding its mechanism of action. The several serious side effects of cisplatin therapy and the lack of consensus regarding the ideal dosage regimen necessitate the development of a quantitative model for cisplatin action. A first-level mathematical model is presented for the cytotoxicity of cisplatin which predicts the survival of cancer cells when subjected to a given dose of this antitumor drug. This model comprises of (i) an uptake model that describes the movement of cisplatin molecules from the extracellular medium to the cell nucleus and the formation (and repair) of cisplatin−DNA adducts and (ii) a tolerance model that relates the quantity of cisplatin−DNA adducts formed inside the cell nuclei in a tumor to the fraction of tumor cells that are killed. The predictions of the model are in good agreement with in vitro experimental data obtained for carcinoma cell lines. To the best of our knowledge, this is the first model combining the uptake of cisplatin (consistent with the biochemical mechanism of action) with cell death (based on cisplatin−DNA adducts). It predicts a Pareto-type set of dosage regimen (dosage, Cext, vs exposure time, texp) of cisplatin to obtain a desired chemotherapeutic efficacy. Some reported patient-data is consistent with this prediction DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102360e Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Steam reforming of ethanol in a microchannel reactor : kinetic study and reactor simulation Type de document : texte imprimé Auteurs : Nageswara Rao Peela, Auteur ; Deepak Kunzru, Auteur Année de publication : 2012 Article en page(s) : pp. 12881-12894 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor Kinetics Microreactor Steam reforming Résumé : The kinetics of steam reforming of ethanol (SRE) was determined at atmospheric pressure in the temperature range of 450―550 °C over 2% Rh/20% CeO2/Al2O3 in a microchannel reactor. The product distribution could be explained by a reaction scheme consisting of four reactions: reaction of steam with ethanol, decomposition of ethanol, methane steam reforming, and the water-gas shift reaction. The kinetic expression based on Langmuir―Hinshelwood kinetics could explain the experimental data satisfactorily. A two-dimensional simulation was also carried out to predict the performance of a microchannel SRE reactor in which the endothermic heat of reaction was supplied by the co-current flow of a hot gas in the adjacent channel. The performance of the coupled reactor/heat exchange system was evaluated by varying several parameters such as heating side gas velocity and temperature, width of the channel, weight of the catalyst, reactor inlet temperature, and inlet flow rate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267446
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12881-12894[article] Steam reforming of ethanol in a microchannel reactor : kinetic study and reactor simulation [texte imprimé] / Nageswara Rao Peela, Auteur ; Deepak Kunzru, Auteur . - 2012 . - pp. 12881-12894.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12881-12894
Mots-clés : Reactor Kinetics Microreactor Steam reforming Résumé : The kinetics of steam reforming of ethanol (SRE) was determined at atmospheric pressure in the temperature range of 450―550 °C over 2% Rh/20% CeO2/Al2O3 in a microchannel reactor. The product distribution could be explained by a reaction scheme consisting of four reactions: reaction of steam with ethanol, decomposition of ethanol, methane steam reforming, and the water-gas shift reaction. The kinetic expression based on Langmuir―Hinshelwood kinetics could explain the experimental data satisfactorily. A two-dimensional simulation was also carried out to predict the performance of a microchannel SRE reactor in which the endothermic heat of reaction was supplied by the co-current flow of a hot gas in the adjacent channel. The performance of the coupled reactor/heat exchange system was evaluated by varying several parameters such as heating side gas velocity and temperature, width of the channel, weight of the catalyst, reactor inlet temperature, and inlet flow rate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267446 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Multicomponent dosing in membrane reactors including recycling — concept and demonstration for the oxidative dehydrogenation of propane Type de document : texte imprimé Auteurs : Christof Hamel, Auteur ; Tanya Wolff, Auteur ; Pushpavanam Subramaniam, Auteur Année de publication : 2012 Article en page(s) : pp. 12895-12903 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dehydrogenation Oxidation Recycling Membrane reactor Résumé : The potential of a multicomponent distributed reactant dosing via membranes for enhancing selectivity and yield in a network of series and parallel reactions is investigated in this work. In a preliminary theoretical feasibility study, the optimal local concentrations of the various reactants used to improve the selectivity and conversion of the desired intermediate product were determined. These results were extended to a case study. For this examination, the oxidative dehydrogenation of propane to the kinetically limited intermediate product propylene on a VOx/γ-Al2O3 catalyst was considered. The kinetic equations and parameters were first estimated. It is shown that, compared to a single-component dosing of O2 via membranes, the yield of propylene can be almost trebled via a controlled simultaneous dosing of oxygen and propane. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267447
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12895-12903[article] Multicomponent dosing in membrane reactors including recycling — concept and demonstration for the oxidative dehydrogenation of propane [texte imprimé] / Christof Hamel, Auteur ; Tanya Wolff, Auteur ; Pushpavanam Subramaniam, Auteur . - 2012 . - pp. 12895-12903.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12895-12903
Mots-clés : Dehydrogenation Oxidation Recycling Membrane reactor Résumé : The potential of a multicomponent distributed reactant dosing via membranes for enhancing selectivity and yield in a network of series and parallel reactions is investigated in this work. In a preliminary theoretical feasibility study, the optimal local concentrations of the various reactants used to improve the selectivity and conversion of the desired intermediate product were determined. These results were extended to a case study. For this examination, the oxidative dehydrogenation of propane to the kinetically limited intermediate product propylene on a VOx/γ-Al2O3 catalyst was considered. The kinetic equations and parameters were first estimated. It is shown that, compared to a single-component dosing of O2 via membranes, the yield of propylene can be almost trebled via a controlled simultaneous dosing of oxygen and propane. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267447 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Integrated multiscale methodology for virtual prototyping of porous catalysts Type de document : texte imprimé Auteurs : V. Novak, Auteur ; P. Koci, Auteur ; F. Stepanek, Auteur Année de publication : 2012 Article en page(s) : pp.12904–12914 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Porous catalysts Résumé : The microstructure of the support determines a key property of porous catalysts—effective diffusivity. Typically, supporting materials with bimodal pore size distribution are used that involve both meso- and macropores. Spatial distribution of active metal crystallites within the porous support then influences reaction rates and conversions. To optimize the catalyst support microstructure and ultimately the whole catalyst, it is necessary to relate quantitatively the morphological features of the porous structure both to its preparation conditions and to the final transport properties and catalyst performance under reaction conditions. In this paper we demonstrate the application of novel models based on the generalized volume-of-fluid method and 3D digital reconstruction of a porous structure. The procedure includes simulation of porous support formation (virtual packing of primary particles of defined shapes and sizes), drying and crystallization of impregnated metal solution (growth of metal nanoparticles), and solution of reaction and transport within the final virtual catalyst structure to obtain volume-averaged reaction rates that are then used in a full-scale model of a catalytic monolith reactor. A parametric study is performed to investigate the effects of the sizes of primary particles (influencing the meso- and macroporosity and pore sizes) and active metal impregnation conditions (influencing the distribution of active catalytic surface area) on the macroscopic activity of a catalytic monolith with Pt/γ-Al2O3 washcoat used for automotive exhaust gas aftertreatment. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003347
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp.12904–12914[article] Integrated multiscale methodology for virtual prototyping of porous catalysts [texte imprimé] / V. Novak, Auteur ; P. Koci, Auteur ; F. Stepanek, Auteur . - 2012 . - pp.12904–12914.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp.12904–12914
Mots-clés : Porous catalysts Résumé : The microstructure of the support determines a key property of porous catalysts—effective diffusivity. Typically, supporting materials with bimodal pore size distribution are used that involve both meso- and macropores. Spatial distribution of active metal crystallites within the porous support then influences reaction rates and conversions. To optimize the catalyst support microstructure and ultimately the whole catalyst, it is necessary to relate quantitatively the morphological features of the porous structure both to its preparation conditions and to the final transport properties and catalyst performance under reaction conditions. In this paper we demonstrate the application of novel models based on the generalized volume-of-fluid method and 3D digital reconstruction of a porous structure. The procedure includes simulation of porous support formation (virtual packing of primary particles of defined shapes and sizes), drying and crystallization of impregnated metal solution (growth of metal nanoparticles), and solution of reaction and transport within the final virtual catalyst structure to obtain volume-averaged reaction rates that are then used in a full-scale model of a catalytic monolith reactor. A parametric study is performed to investigate the effects of the sizes of primary particles (influencing the meso- and macroporosity and pore sizes) and active metal impregnation conditions (influencing the distribution of active catalytic surface area) on the macroscopic activity of a catalytic monolith with Pt/γ-Al2O3 washcoat used for automotive exhaust gas aftertreatment. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003347 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Photocatalytic activity of combustion synthesized ZrO2 and ZrO2 – TiO2 mixed oxides Type de document : texte imprimé Auteurs : Sneha Polisetti, Auteur ; Parag A. Deshpande, Auteur ; Giridhar Madras, Auteur Année de publication : 2012 Article en page(s) : pp. 12915-12924 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Titanium oxide Combustion Photocatalysis Résumé : Tetragonal ZrO2, synthesized by solution combustion technique, was found to be photocatalytically active for the degradation of anionic dyes. The compound was characterized by FT-Raman spectroscopy, X-ray photoelectron spectroscopy, FT-infrared spectroscopy, UV―vis spectroscopy, BET surface area analysis, and zero point charge pH measurement. A high concentration of surface hydroxyl groups was observed over the catalyst, as confirmed by XPS and FTIR. The photocatalytic degradation of orange G, amido black, remazol brilliant blue R, and alizarin cyanine green (ACG) was carried out with this material. The effect of pH, inorganic salts, and H2O2 on the activity of the catalyst was also studied, and it was found that the catalyst maintained its activity at a wide range of pH and in the presence of inorganic salts. Having established that ZrO2 was photocatalytically active, mixed oxide catalysts of TiO2―ZrO2 were also tested for the photocatalytic degradation of ACG, and the 50% ZrO2―TiO2 mixed oxides showed activity that was comparable to the activity of TiO2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267449
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12915-12924[article] Photocatalytic activity of combustion synthesized ZrO2 and ZrO2 – TiO2 mixed oxides [texte imprimé] / Sneha Polisetti, Auteur ; Parag A. Deshpande, Auteur ; Giridhar Madras, Auteur . - 2012 . - pp. 12915-12924.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12915-12924
Mots-clés : Titanium oxide Combustion Photocatalysis Résumé : Tetragonal ZrO2, synthesized by solution combustion technique, was found to be photocatalytically active for the degradation of anionic dyes. The compound was characterized by FT-Raman spectroscopy, X-ray photoelectron spectroscopy, FT-infrared spectroscopy, UV―vis spectroscopy, BET surface area analysis, and zero point charge pH measurement. A high concentration of surface hydroxyl groups was observed over the catalyst, as confirmed by XPS and FTIR. The photocatalytic degradation of orange G, amido black, remazol brilliant blue R, and alizarin cyanine green (ACG) was carried out with this material. The effect of pH, inorganic salts, and H2O2 on the activity of the catalyst was also studied, and it was found that the catalyst maintained its activity at a wide range of pH and in the presence of inorganic salts. Having established that ZrO2 was photocatalytically active, mixed oxide catalysts of TiO2―ZrO2 were also tested for the photocatalytic degradation of ACG, and the 50% ZrO2―TiO2 mixed oxides showed activity that was comparable to the activity of TiO2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267449 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Numerical analysis of fractal catalyst structuring in microreactors Type de document : texte imprimé Auteurs : Venkat Reddy Regatte, Auteur ; Niket S. Kaisare, Auteur Année de publication : 2012 Article en page(s) : pp. 12925-12932 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microreactor Catalyst Fractal Numerical simulation analysis Résumé : The objective of this work is to verify the feasibility of implementing fractal structuring to reduce the amount of active catalyst surface required in microreactors. This work follows up on the work by Phillips et al. [Chem. Eng. ScL, 2003, 58, 2403―2408], where the authors reported the use of Cantor triads to reduce the total amount of active catalyst in a mass-transfer-limited system. They considered flat-plate geometry with infinitely fast reactions. This work is extended to realistic microreactors with finite rate chemistry to study the effect of catalyst structuring in the presence of flow confinement. Fractal and periodic patterns are formed by removing the catalyst from various sections along the reactor wall, resulting in alternating catalytic and noncatalytic segments. Two-dimensional computational fluid dynamics (CFD) simulations of tubular microreactor channel with catalyst structuring are performed. Our results show that the role of catalyst structuring confined geometry is rather modest, compared to the open (flat-plate) geometries considered so far. We also show that singularities (boundary of noncatalytic and catalytic segments) formed with catalyst structuring, and not the fractal pattern itself, are responsible for improved conversion from the microreactor. Large gradients at singularities result in enhanced mass transfer, which is analyzed using Sherwood number correlations. The effect of various operating parameters is investigated. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267450
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12925-12932[article] Numerical analysis of fractal catalyst structuring in microreactors [texte imprimé] / Venkat Reddy Regatte, Auteur ; Niket S. Kaisare, Auteur . - 2012 . - pp. 12925-12932.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12925-12932
Mots-clés : Microreactor Catalyst Fractal Numerical simulation analysis Résumé : The objective of this work is to verify the feasibility of implementing fractal structuring to reduce the amount of active catalyst surface required in microreactors. This work follows up on the work by Phillips et al. [Chem. Eng. ScL, 2003, 58, 2403―2408], where the authors reported the use of Cantor triads to reduce the total amount of active catalyst in a mass-transfer-limited system. They considered flat-plate geometry with infinitely fast reactions. This work is extended to realistic microreactors with finite rate chemistry to study the effect of catalyst structuring in the presence of flow confinement. Fractal and periodic patterns are formed by removing the catalyst from various sections along the reactor wall, resulting in alternating catalytic and noncatalytic segments. Two-dimensional computational fluid dynamics (CFD) simulations of tubular microreactor channel with catalyst structuring are performed. Our results show that the role of catalyst structuring confined geometry is rather modest, compared to the open (flat-plate) geometries considered so far. We also show that singularities (boundary of noncatalytic and catalytic segments) formed with catalyst structuring, and not the fractal pattern itself, are responsible for improved conversion from the microreactor. Large gradients at singularities result in enhanced mass transfer, which is analyzed using Sherwood number correlations. The effect of various operating parameters is investigated. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267450 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Single - event microKinetics of aromatics hydrogenation on Pt / H - ZSM22 Type de document : texte imprimé Auteurs : Tapan Bera, Auteur ; Joris W. Thybaut, Auteur ; Guy B. Marin, Auteur Année de publication : 2012 Article en page(s) : pp.12933–12945 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : MicroKinetics Hydrogenation Résumé : A fundamental Single-Event MicroKinetic (SEMK) model for the hydrogenation of aromatic components on a Pt catalyst has been developed. It is based on the Horiuti-Polanyi mechanism considering atomic hydrogen addition steps to the (partially hydrogenated) aromatic species on the catalyst surface. The reaction network used accounts for the position at which the hydrogen atoms are added to the ring. In accordance with a quantum chemical assessment of the reaction pathway it was assumed that the kinetic parameters only depend on the saturation degree of the nearest neighbor carbon atoms and the branching degree of the carbon atom involved in the hydrogen atom addition. Six reactions families, of which three occur in the reaction network for benzene, are considered. The total number of 18 model parameters was reduced to 7 by calculation of the pre-exponential factors and by accounting for thermodynamic constraints. Experimental benzene hydrogenation data measured at temperatures in the range from 423 to 498 K, benzene inlet partial pressures in the range from 10 to 60 kPa, and hydrogen inlet partial pressures from 100 to 600 kPa on Pt catalyst have been regressed. In accordance with quantum chemical, statistical, and thermodynamic calculations, the selected version of the model gives the best description of the data with an F value of 4150. According to this selected SEMK model, the activation energies for the hydrogen addition to a carbon atom between two unsaturated or two saturated carbon atoms are identical and lower than the activation energy for hydrogen addition to a carbon atom between an unsaturated and saturated hydrogen atom. The estimated chemisorption enthalpy of hydrogen amounts to −59.4 kJ mol–1 and corresponds with an average surface coverage of 30%. A value of −56.0 kJ mol–1 for the chemisorption enthalpy of benzene is obtained. The total surface coverage by hydrocarbon species amounts to 60% under typical reaction conditions, without a pronounced Most Abundant Surface Intermediate (MASI). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200541q
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp.12933–12945[article] Single - event microKinetics of aromatics hydrogenation on Pt / H - ZSM22 [texte imprimé] / Tapan Bera, Auteur ; Joris W. Thybaut, Auteur ; Guy B. Marin, Auteur . - 2012 . - pp.12933–12945.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp.12933–12945
Mots-clés : MicroKinetics Hydrogenation Résumé : A fundamental Single-Event MicroKinetic (SEMK) model for the hydrogenation of aromatic components on a Pt catalyst has been developed. It is based on the Horiuti-Polanyi mechanism considering atomic hydrogen addition steps to the (partially hydrogenated) aromatic species on the catalyst surface. The reaction network used accounts for the position at which the hydrogen atoms are added to the ring. In accordance with a quantum chemical assessment of the reaction pathway it was assumed that the kinetic parameters only depend on the saturation degree of the nearest neighbor carbon atoms and the branching degree of the carbon atom involved in the hydrogen atom addition. Six reactions families, of which three occur in the reaction network for benzene, are considered. The total number of 18 model parameters was reduced to 7 by calculation of the pre-exponential factors and by accounting for thermodynamic constraints. Experimental benzene hydrogenation data measured at temperatures in the range from 423 to 498 K, benzene inlet partial pressures in the range from 10 to 60 kPa, and hydrogen inlet partial pressures from 100 to 600 kPa on Pt catalyst have been regressed. In accordance with quantum chemical, statistical, and thermodynamic calculations, the selected version of the model gives the best description of the data with an F value of 4150. According to this selected SEMK model, the activation energies for the hydrogen addition to a carbon atom between two unsaturated or two saturated carbon atoms are identical and lower than the activation energy for hydrogen addition to a carbon atom between an unsaturated and saturated hydrogen atom. The estimated chemisorption enthalpy of hydrogen amounts to −59.4 kJ mol–1 and corresponds with an average surface coverage of 30%. A value of −56.0 kJ mol–1 for the chemisorption enthalpy of benzene is obtained. The total surface coverage by hydrocarbon species amounts to 60% under typical reaction conditions, without a pronounced Most Abundant Surface Intermediate (MASI). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200541q Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Oxidation of chloride ion on platinum electrode : dynamics of electrode passivation and its effect on oxidation kinetics Type de document : texte imprimé Auteurs : Rajkumar S. Patil, Auteur ; Vinay A. Juvekar, Auteur ; Vijay M. Naik, Auteur Année de publication : 2012 Article en page(s) : pp. 12946–12959 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxidation Ion Kinetics Résumé : Kinetics of oxidation of chloride ion is studied on both active platinum electrode and that undergoing transient passivation. Experiments are conducted in concentrated NaCl solution at rotating disk electrode. It is observed that on the active platinum electrode, oxidation is very fast, and hence the current density is controlled by the ohmic resistance of the solution. Electrode kinetics becomes important only when the electrode is passivated to a significant extent. Kinetics of chloride oxidation on the electrode undergoing passivation is modeled using the Butler–Volmer equation, in which the contribution from the ohmic resistance of the solution is incorporated. Two regimes of passivation are identified. The first is the fast regime corresponding to the formation of the platinum oxide monolayer. In this regime, the rate of passivation is first order in the concentration of the metal sites on the surface. In the slow passivation regime, the exchange current density for chloride oxidation is found to vary inversely with square root of time. This regime is modeled by considering unsteady diffusion of oxygen ions through the metal lattice. From this analysis it is concluded that the chloride oxidation current is almost totally contributed by a small fraction of the active metal sites which are continuously being regenerated as a result of diffusion of oxygen ions from the surface into the bulk of the metal. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200663a
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12946–12959[article] Oxidation of chloride ion on platinum electrode : dynamics of electrode passivation and its effect on oxidation kinetics [texte imprimé] / Rajkumar S. Patil, Auteur ; Vinay A. Juvekar, Auteur ; Vijay M. Naik, Auteur . - 2012 . - pp. 12946–12959.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12946–12959
Mots-clés : Oxidation Ion Kinetics Résumé : Kinetics of oxidation of chloride ion is studied on both active platinum electrode and that undergoing transient passivation. Experiments are conducted in concentrated NaCl solution at rotating disk electrode. It is observed that on the active platinum electrode, oxidation is very fast, and hence the current density is controlled by the ohmic resistance of the solution. Electrode kinetics becomes important only when the electrode is passivated to a significant extent. Kinetics of chloride oxidation on the electrode undergoing passivation is modeled using the Butler–Volmer equation, in which the contribution from the ohmic resistance of the solution is incorporated. Two regimes of passivation are identified. The first is the fast regime corresponding to the formation of the platinum oxide monolayer. In this regime, the rate of passivation is first order in the concentration of the metal sites on the surface. In the slow passivation regime, the exchange current density for chloride oxidation is found to vary inversely with square root of time. This regime is modeled by considering unsteady diffusion of oxygen ions through the metal lattice. From this analysis it is concluded that the chloride oxidation current is almost totally contributed by a small fraction of the active metal sites which are continuously being regenerated as a result of diffusion of oxygen ions from the surface into the bulk of the metal. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200663a Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Incremental identification of reaction and mass – transfer kinetics using the concept of extents Type de document : texte imprimé Auteurs : Nirav Bhatt, Auteur ; Michael Amrhein, Auteur ; Dominique Bonvin, Auteur Année de publication : 2012 Article en page(s) : pp. 12960–12974 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mass transfer Kinetics Résumé : This paper proposes a variation of the incremental approach to identify reaction and mass-transfer kinetics from concentration measurements for both homogeneous and gas–liquid reaction systems. This incremental approach proceeds in two steps: (i) computation of the extents of reaction and mass transfer from concentration measurements without explicit knowledge of the reaction and mass-transfer rate expressions, and (ii) estimation of the rate parameters for each rate expression individually from the computed extents using the integral method. The novelty consists in using extents, thereby avoiding differentiation of measured concentrations. For the computation of extents, two cases are considered: a linear transformation is used if the concentrations of all liquid-phase species can be measured; otherwise, if the concentrations of only a subset of the liquid-phase species are available, an approach that uses additional measurements of flow rates and possibly gas-phase concentration is proposed. The incremental identification approach is illustrated in simulation via two reaction systems, namely, the homogeneous acetoacetylation of pyrrole and the gas–liquid chlorination of butanoic acid. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2007196
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12960–12974[article] Incremental identification of reaction and mass – transfer kinetics using the concept of extents [texte imprimé] / Nirav Bhatt, Auteur ; Michael Amrhein, Auteur ; Dominique Bonvin, Auteur . - 2012 . - pp. 12960–12974.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12960–12974
Mots-clés : Mass transfer Kinetics Résumé : This paper proposes a variation of the incremental approach to identify reaction and mass-transfer kinetics from concentration measurements for both homogeneous and gas–liquid reaction systems. This incremental approach proceeds in two steps: (i) computation of the extents of reaction and mass transfer from concentration measurements without explicit knowledge of the reaction and mass-transfer rate expressions, and (ii) estimation of the rate parameters for each rate expression individually from the computed extents using the integral method. The novelty consists in using extents, thereby avoiding differentiation of measured concentrations. For the computation of extents, two cases are considered: a linear transformation is used if the concentrations of all liquid-phase species can be measured; otherwise, if the concentrations of only a subset of the liquid-phase species are available, an approach that uses additional measurements of flow rates and possibly gas-phase concentration is proposed. The incremental identification approach is illustrated in simulation via two reaction systems, namely, the homogeneous acetoacetylation of pyrrole and the gas–liquid chlorination of butanoic acid. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2007196 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Kinetic modeling and statistical optimization of lipase catalyzed enantioselective resolution of (R,S) - 2 - pentanol Type de document : texte imprimé Auteurs : Jyoti B. Sontakke, Auteur ; Ganapati D. Yadav, Auteur Année de publication : 2012 Article en page(s) : pp. 12975-12983 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Enzymatic catalysis Optimization Kinetic model Résumé : S-2-pentanol is a chiral intermediate in the synthesis of several potential antialzheimer's drugs that inhibit β-amyloid peptide release or its synthesis. The present work focuses on the kinetic resolution of (R,S)-2-pentanol using vinyl acetate as an acyl donor. Effects of various parameters were studied to deduce the kinetics and mechanism of the reaction. Novozyme 435 was found to be the most efficient catalyst among different catalysts studied Response Surface methodology and Box-Behnken design were employed to evaluate the effect of process parameters such as speed of agitation, enzyme loading, temperature and acyl donor/ alcohol molar ratio on conversion, enantiomeric excess, enantioselectivity and initial rate. Initial rate data and progress curve data were used to arrive at a suitable model. Ping-pong bi-bi mechanism with 2-pentanol inhibition was found to describe the kinetics of the reaction. The kinetic parameters evaluated from initial rate data were used to simulate the experimental results. There was a very good agreement between theory and experiment. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267454
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12975-12983[article] Kinetic modeling and statistical optimization of lipase catalyzed enantioselective resolution of (R,S) - 2 - pentanol [texte imprimé] / Jyoti B. Sontakke, Auteur ; Ganapati D. Yadav, Auteur . - 2012 . - pp. 12975-12983.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12975-12983
Mots-clés : Modeling Enzymatic catalysis Optimization Kinetic model Résumé : S-2-pentanol is a chiral intermediate in the synthesis of several potential antialzheimer's drugs that inhibit β-amyloid peptide release or its synthesis. The present work focuses on the kinetic resolution of (R,S)-2-pentanol using vinyl acetate as an acyl donor. Effects of various parameters were studied to deduce the kinetics and mechanism of the reaction. Novozyme 435 was found to be the most efficient catalyst among different catalysts studied Response Surface methodology and Box-Behnken design were employed to evaluate the effect of process parameters such as speed of agitation, enzyme loading, temperature and acyl donor/ alcohol molar ratio on conversion, enantiomeric excess, enantioselectivity and initial rate. Initial rate data and progress curve data were used to arrive at a suitable model. Ping-pong bi-bi mechanism with 2-pentanol inhibition was found to describe the kinetics of the reaction. The kinetic parameters evaluated from initial rate data were used to simulate the experimental results. There was a very good agreement between theory and experiment. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267454 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Controlled crystallization of macromolecules using patterned substrates in a sandwiched plate geometry Type de document : texte imprimé Auteurs : Anindita Sengupta Ghatak, Auteur ; Animangsu Ghatak, Auteur Année de publication : 2012 Article en page(s) : pp. 12984–12989 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Macromolecules Résumé : Crystallization of macromolecules such as proteins and peptides is known to be influenced by the topographical and chemical heterogeneity of the substrate. However, controlling the nucleation and the growth of crystal on such surfaces has been an issue. Here, we present systematic experiments carried out on hydrophilic elastomeric substrates topographically patterned by forming stretch induced surface wrinkles; the distance between the wrinkles, importantly the density of occurrence of defects between the wrinkles, is systematically varied. Furthermore, to maximize the effect of the substrates, the crystallization experiment is carried out between two such parallel substrates, the gap between which is maintained by using spacers. This process results in very controlled evaporation of the solvent. Experiments with two different model proteins: hen egg-white lysozyme and Thaumatin from Thaoumatococcus daniellii show that on surfaces with uniformly spaced wrinkles the crystals nucleate extensively but with insignificant growth. However, when a small number of defects are introduced into the patterns, fewer crystals nucleate, which grow to form large crystals. With further increase in the defect density, extent of nucleation increases again, but with decrease in the crystal growth. Thus, the crystal size attains maxima at an intermediate wavelength of the wrinkles and the defect density. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102596c
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12984–12989[article] Controlled crystallization of macromolecules using patterned substrates in a sandwiched plate geometry [texte imprimé] / Anindita Sengupta Ghatak, Auteur ; Animangsu Ghatak, Auteur . - 2012 . - pp. 12984–12989.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12984–12989
Mots-clés : Macromolecules Résumé : Crystallization of macromolecules such as proteins and peptides is known to be influenced by the topographical and chemical heterogeneity of the substrate. However, controlling the nucleation and the growth of crystal on such surfaces has been an issue. Here, we present systematic experiments carried out on hydrophilic elastomeric substrates topographically patterned by forming stretch induced surface wrinkles; the distance between the wrinkles, importantly the density of occurrence of defects between the wrinkles, is systematically varied. Furthermore, to maximize the effect of the substrates, the crystallization experiment is carried out between two such parallel substrates, the gap between which is maintained by using spacers. This process results in very controlled evaporation of the solvent. Experiments with two different model proteins: hen egg-white lysozyme and Thaumatin from Thaoumatococcus daniellii show that on surfaces with uniformly spaced wrinkles the crystals nucleate extensively but with insignificant growth. However, when a small number of defects are introduced into the patterns, fewer crystals nucleate, which grow to form large crystals. With further increase in the defect density, extent of nucleation increases again, but with decrease in the crystal growth. Thus, the crystal size attains maxima at an intermediate wavelength of the wrinkles and the defect density. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102596c Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Measurement and analysis of effective thermal conductivity of MmNi4.5Al0.5 hydride bed Type de document : texte imprimé Auteurs : E. Anil Kumar, Auteur ; M. Prakash Maiya, Auteur ; S. Srinivasa Murthy, Auteur Année de publication : 2012 Article en page(s) : pp. 12990–12999 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermal conductivity Résumé : The effective thermal conductivity (ke) of a MmNi4.5Al0.5 hydride powder bed was measured using an one-dimensional steady-state axial heat transfer comparative method. The experiments showed that ke lies between 0.1 and 1.2 W/m K in the pressure and the temperature ranges of 0–50 bar and 0–100 °C, respectively. While hydrogen pressure and concentration showed strong influence on ke over the complete range, the temperature effects were minimal. Thermal conductivity of the solid materials, MmNi4.5Al0.5 alloy and its hydrides, was also back calculated from the experimentally measured ke values. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200116d
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12990–12999[article] Measurement and analysis of effective thermal conductivity of MmNi4.5Al0.5 hydride bed [texte imprimé] / E. Anil Kumar, Auteur ; M. Prakash Maiya, Auteur ; S. Srinivasa Murthy, Auteur . - 2012 . - pp. 12990–12999.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12990–12999
Mots-clés : Thermal conductivity Résumé : The effective thermal conductivity (ke) of a MmNi4.5Al0.5 hydride powder bed was measured using an one-dimensional steady-state axial heat transfer comparative method. The experiments showed that ke lies between 0.1 and 1.2 W/m K in the pressure and the temperature ranges of 0–50 bar and 0–100 °C, respectively. While hydrogen pressure and concentration showed strong influence on ke over the complete range, the temperature effects were minimal. Thermal conductivity of the solid materials, MmNi4.5Al0.5 alloy and its hydrides, was also back calculated from the experimentally measured ke values. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200116d Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Filling characteristics for an activated carbon based adsorbed natural gas storage system Type de document : texte imprimé Auteurs : Pradeepta K. Sahoo, Auteur ; Mathew John, Auteur ; Bharat L. Newalkar, Auteur Année de publication : 2012 Article en page(s) : pp. 13000–13011 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon Natural gas Résumé : The storage capacity of an activated carbon bed is studied using a 2D transport model with constant inlet flow conditions. The predicted filling times and variation in bed pressure and temperature are in good agreement with experimental observations obtained using a 1.82 L prototype ANG storage cylinder. Storage efficiencies based on the maximum achievable V/V (volume of gas/volume of container) and filling times are used to quantify the performance of the charging process. For the high permeability beds used in the experiments, storage efficiencies are controlled by the rate of heat removal. Filling times, defined as the time at which the bed pressure reaches 3.5 MPa, range from 120 to 3.4 min for inlet flow rates of 1.0 L min–1 and 30.0 L min–1, respectively. The corresponding storage efficiencies, ηs, vary from 90% to 76%, respectively. Simulations with L/D ratios ranging from 0.35 to 7.8 indicate that the storage efficiencies can be improved with an increase in the L/D ratios and/or with water cooled convection. Thus for an inlet flow rate of 30.0 L min–1, an ηs value of 90% can be obtained with water cooling for an L/D ratio of 7.8 and a filling time of a few minutes. In the absence of water cooling the ηs value reduces to 83% at the same L/D ratio. Our study suggests that with an appropriate choice of cylinder dimensions, solutions based on convective cooling during adsorptive storage are possible with some compromise in the storage capacity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200241x
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13000–13011[article] Filling characteristics for an activated carbon based adsorbed natural gas storage system [texte imprimé] / Pradeepta K. Sahoo, Auteur ; Mathew John, Auteur ; Bharat L. Newalkar, Auteur . - 2012 . - pp. 13000–13011.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13000–13011
Mots-clés : Carbon Natural gas Résumé : The storage capacity of an activated carbon bed is studied using a 2D transport model with constant inlet flow conditions. The predicted filling times and variation in bed pressure and temperature are in good agreement with experimental observations obtained using a 1.82 L prototype ANG storage cylinder. Storage efficiencies based on the maximum achievable V/V (volume of gas/volume of container) and filling times are used to quantify the performance of the charging process. For the high permeability beds used in the experiments, storage efficiencies are controlled by the rate of heat removal. Filling times, defined as the time at which the bed pressure reaches 3.5 MPa, range from 120 to 3.4 min for inlet flow rates of 1.0 L min–1 and 30.0 L min–1, respectively. The corresponding storage efficiencies, ηs, vary from 90% to 76%, respectively. Simulations with L/D ratios ranging from 0.35 to 7.8 indicate that the storage efficiencies can be improved with an increase in the L/D ratios and/or with water cooled convection. Thus for an inlet flow rate of 30.0 L min–1, an ηs value of 90% can be obtained with water cooling for an L/D ratio of 7.8 and a filling time of a few minutes. In the absence of water cooling the ηs value reduces to 83% at the same L/D ratio. Our study suggests that with an appropriate choice of cylinder dimensions, solutions based on convective cooling during adsorptive storage are possible with some compromise in the storage capacity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200241x Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Biomimicked superhydrophobic polymeric and carbon surfaces Type de document : texte imprimé Auteurs : Chandra S. Sharma, Auteur ; Kumar Abhishek, Auteur ; Hari Katepalli, Auteur Année de publication : 2012 Article en page(s) : pp. 13012–13020 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon Polymer Résumé : We report two direct and easy ways of fabricating stable, superhydrophobic polymeric and carbon surfaces directly by biomimicking the patterns found on natural plant leaves by micromolding and nanoimprint lithography. Two distinct classes of naturally occurring microtextures on superhydrophobic leaves were mimicked in this study, which include leaves of Elephant creeper (Argyreia Nervosa) and Nasturtium (Tropaeolum Majus). These show structural superhydrophobicity derived from high aspect ratio hairs and lower aspect ratio microtextures, respectively. Both the textures could be replicated by micromolding in different polymers, polydimethylsiloxane, polystyrene, and an organic resorcinol-formaldehyde (RF) gel. Patterned RF gel surfaces yielded superhydrophobic carbon surfaces upon pyrolysis because RF gel is a polymer precursor to glassy carbon. The nanoimprint lithography could be used for a direct transfer of the lower aspect ratio leaf patterns on the surfaces of various other polymers like poly(ethylene terephthalate) and poly(methyl methacrylate). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200369r
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13012–13020[article] Biomimicked superhydrophobic polymeric and carbon surfaces [texte imprimé] / Chandra S. Sharma, Auteur ; Kumar Abhishek, Auteur ; Hari Katepalli, Auteur . - 2012 . - pp. 13012–13020.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13012–13020
Mots-clés : Carbon Polymer Résumé : We report two direct and easy ways of fabricating stable, superhydrophobic polymeric and carbon surfaces directly by biomimicking the patterns found on natural plant leaves by micromolding and nanoimprint lithography. Two distinct classes of naturally occurring microtextures on superhydrophobic leaves were mimicked in this study, which include leaves of Elephant creeper (Argyreia Nervosa) and Nasturtium (Tropaeolum Majus). These show structural superhydrophobicity derived from high aspect ratio hairs and lower aspect ratio microtextures, respectively. Both the textures could be replicated by micromolding in different polymers, polydimethylsiloxane, polystyrene, and an organic resorcinol-formaldehyde (RF) gel. Patterned RF gel surfaces yielded superhydrophobic carbon surfaces upon pyrolysis because RF gel is a polymer precursor to glassy carbon. The nanoimprint lithography could be used for a direct transfer of the lower aspect ratio leaf patterns on the surfaces of various other polymers like poly(ethylene terephthalate) and poly(methyl methacrylate). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200369r Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Carbothermal synthesis of aerosol - based adsorptive - reactive iron – carbon particles for the remediation of chlorinated hydrocarbons Type de document : texte imprimé Auteurs : Jingjing Zhan, Auteur ; Bhanukiran Sunkara, Auteur ; Jingjian Tang, Auteur Année de publication : 2012 Article en page(s) : pp. 13021-13029 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Decontamination Aerosols Résumé : Spherical iron—carbon nanocomposites were synthesized through a facile aerosol-based process and a subsequent carbothermal reduction. The distribution and immobilization of iron particles throughout the carbon microspheres prevents nanoiron aggregation, allowing the maintenance of particle reactivity. The carbon microspheres allow adsorption of TCE, thus removing dissolved TCE rapidly and facilitating reaction by increasing the local concentration ofTCE in the vicinity of iron particles. The strongly adsorptive property of the composites may prevent release of toxic chlorinated intermediate products. The nanoscale composite particle size is in the optimal range for effective transport through groundwater saturated sediments. It is also shown that carbothermal treatment of the composite material leads to highly porous carbon materials containing zerovalent iron species, a necessary reactive component in the reaction pathway. The mesoporous structure generated allows access to internal reactive sites. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267459
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13021-13029[article] Carbothermal synthesis of aerosol - based adsorptive - reactive iron – carbon particles for the remediation of chlorinated hydrocarbons [texte imprimé] / Jingjing Zhan, Auteur ; Bhanukiran Sunkara, Auteur ; Jingjian Tang, Auteur . - 2012 . - pp. 13021-13029.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13021-13029
Mots-clés : Decontamination Aerosols Résumé : Spherical iron—carbon nanocomposites were synthesized through a facile aerosol-based process and a subsequent carbothermal reduction. The distribution and immobilization of iron particles throughout the carbon microspheres prevents nanoiron aggregation, allowing the maintenance of particle reactivity. The carbon microspheres allow adsorption of TCE, thus removing dissolved TCE rapidly and facilitating reaction by increasing the local concentration ofTCE in the vicinity of iron particles. The strongly adsorptive property of the composites may prevent release of toxic chlorinated intermediate products. The nanoscale composite particle size is in the optimal range for effective transport through groundwater saturated sediments. It is also shown that carbothermal treatment of the composite material leads to highly porous carbon materials containing zerovalent iron species, a necessary reactive component in the reaction pathway. The mesoporous structure generated allows access to internal reactive sites. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267459 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Polymer - functionalized nanoparticles for improving waterflood sweep efficiency : characterization and transport properties Type de document : texte imprimé Auteurs : R. Ponnapati, Auteur ; O. Karazincir, Auteur ; E. Dao, Auteur Année de publication : 2012 Article en page(s) : pp. 13030-13036 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Transport properties Nanoparticle Résumé : Water-dispersible polymer―silica nanocomposite particles, SiO2―ethylene oxide-based polymer nanoparticles hybrids, were synthesized using a "grafting-from" method, where polymer brushes were grown on silica nanoparticles using living radical polymerization. Water-soluble polymer chains were grown from initiator-tethered 15-nm silica nanopartides with ∼600 chains grafted per nanopartide, resulting in a surface grafting of∼1 chain per square nanometer. The single-phase and multiphase transport properties of low concentration brine dispersions of these polymer nanoparticles hybrids through a Berea sandstone core were measured. Experiments show that, while the viscosity increase is modest for dispersions with concentrations of 0.5― 2 wt % of the nanopartide hybrid, the dispersions were able to transport without hindrance through the porous media and, furthermore, were found to be effective at mobilizing waterflood residual oil. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267460
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13030-13036[article] Polymer - functionalized nanoparticles for improving waterflood sweep efficiency : characterization and transport properties [texte imprimé] / R. Ponnapati, Auteur ; O. Karazincir, Auteur ; E. Dao, Auteur . - 2012 . - pp. 13030-13036.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13030-13036
Mots-clés : Transport properties Nanoparticle Résumé : Water-dispersible polymer―silica nanocomposite particles, SiO2―ethylene oxide-based polymer nanoparticles hybrids, were synthesized using a "grafting-from" method, where polymer brushes were grown on silica nanoparticles using living radical polymerization. Water-soluble polymer chains were grown from initiator-tethered 15-nm silica nanopartides with ∼600 chains grafted per nanopartide, resulting in a surface grafting of∼1 chain per square nanometer. The single-phase and multiphase transport properties of low concentration brine dispersions of these polymer nanoparticles hybrids through a Berea sandstone core were measured. Experiments show that, while the viscosity increase is modest for dispersions with concentrations of 0.5― 2 wt % of the nanopartide hybrid, the dispersions were able to transport without hindrance through the porous media and, furthermore, were found to be effective at mobilizing waterflood residual oil. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267460 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Effect of alkaline hydroxides on the vapor − liquid equilibrium of ammonia / water and the performance of absorption chillers Type de document : texte imprimé Auteurs : Simona Steiu, Auteur ; David Martínez-Maradiaga, Auteur ; Daniel Salavera, Auteur Année de publication : 2012 Article en page(s) : pp. 13037-13044 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Phase equilibrium Liquid vapor Résumé : New simple and accurate correlations of the equilibrium properties and solution enthalpies for NH3/H2O/alkaline hydroxide mixtures are presented for use in the modeling and design of absorption chillers in a temperature range between 273.15 and 353.15 K. The correlations are used to calculate the P—T—x diagrams and show the effect of hydroxide on the liquid-vapor equilibrium. Finally, the correlations presented are used to estimate the improvement in the cycle performance in absorption chillers when NH3/H2O mixtures containing NaOH are used instead of the conventional NH3/H2O mixture. Results show that the addition of hydroxide can significantly decrease the generator temperature of ammonia/water absorption refrigeration cycles while simultaneously increasing the Coefficient of Performance (COP). For a NaOH concentration of 12%, the temperature at the generator decreases by about 17°C, the COP increases by 28%, and the size of the rectifier can be up to 46% less than that required when the conventional NH3/H2O cycle is used. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267461
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13037-13044[article] Effect of alkaline hydroxides on the vapor − liquid equilibrium of ammonia / water and the performance of absorption chillers [texte imprimé] / Simona Steiu, Auteur ; David Martínez-Maradiaga, Auteur ; Daniel Salavera, Auteur . - 2012 . - pp. 13037-13044.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13037-13044
Mots-clés : Phase equilibrium Liquid vapor Résumé : New simple and accurate correlations of the equilibrium properties and solution enthalpies for NH3/H2O/alkaline hydroxide mixtures are presented for use in the modeling and design of absorption chillers in a temperature range between 273.15 and 353.15 K. The correlations are used to calculate the P—T—x diagrams and show the effect of hydroxide on the liquid-vapor equilibrium. Finally, the correlations presented are used to estimate the improvement in the cycle performance in absorption chillers when NH3/H2O mixtures containing NaOH are used instead of the conventional NH3/H2O mixture. Results show that the addition of hydroxide can significantly decrease the generator temperature of ammonia/water absorption refrigeration cycles while simultaneously increasing the Coefficient of Performance (COP). For a NaOH concentration of 12%, the temperature at the generator decreases by about 17°C, the COP increases by 28%, and the size of the rectifier can be up to 46% less than that required when the conventional NH3/H2O cycle is used. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267461 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Optimal plant friendly input design for system identification Type de document : texte imprimé Auteurs : Sridharakumar Narasimhan, Auteur ; S. Arun Srikanth, Auteur ; J. V. N. Sreeram, Auteur Année de publication : 2012 Article en page(s) : pp. 13045-13055 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : System identification Design Résumé : The primary objective in solving optimal input design problems is to obtain maximally informative inputs to be used as perturbation signals in system identification experiments. In plant-fiiendly identification, the designer has to respect constraints on experiment time, input and output amplitudes or input move sizes. This work focuses on plant friendly input design with constraints on input move size and output power. We present a convex relaxation to the problem of designing an informative input subject to input move size and output power constraints. The problem is finitely parametrized using ideas from Tchebycheff systems and reformulated as a SemiDefinite Progamme. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267462
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13045-13055[article] Optimal plant friendly input design for system identification [texte imprimé] / Sridharakumar Narasimhan, Auteur ; S. Arun Srikanth, Auteur ; J. V. N. Sreeram, Auteur . - 2012 . - pp. 13045-13055.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13045-13055
Mots-clés : System identification Design Résumé : The primary objective in solving optimal input design problems is to obtain maximally informative inputs to be used as perturbation signals in system identification experiments. In plant-fiiendly identification, the designer has to respect constraints on experiment time, input and output amplitudes or input move sizes. This work focuses on plant friendly input design with constraints on input move size and output power. We present a convex relaxation to the problem of designing an informative input subject to input move size and output power constraints. The problem is finitely parametrized using ideas from Tchebycheff systems and reformulated as a SemiDefinite Progamme. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267462 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Influence of feed entry on the segregation of a binary mixture of solids in a continuous fast fluidized bed Type de document : texte imprimé Auteurs : K. Ganesh Palappan, Auteur ; P. S. T. Sai, Auteur Année de publication : 2012 Article en page(s) : pp. 13056–13065 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fast fluidized Résumé : Studies on the influence of feed entry on segregation using continuous fast fluidization is not clearly understood even though studies are available on the segregation of particles in continuous bubbling/turbulent fluidized beds. In the present study, four different feed inlet positions are selected and tested in a 69 mm ID and 3.65 m height continuous fast fluidized bed. The feed is a binary mixture of solid particles of the same size, but different density. The inimitable observations noticed at various feed locations on fluidization behavior with segregation is discussed. Change in the feed inlet height of the fluidized bed is reflected drastically on the compositions of top and bottom products. Disparate behavior of continuous fluidization is noticed at selected feed inlet positions. Operation is not stable due to either particle congestion in the feeding line or nonuniform discharge of solids from the fluidized bed when the feed inlet position is located close to distributor. Further an enhanced-feed inlet location created a particle’s cloud above the dense phase. Excess of feed inlet height transformed the binary mixture severance and freeboard height. The optimum operating gas velocity required for maximum separation of both species is identified at every feed entry for different feed rates. A unique feed entry location is recognized for maximum separation of both the species and minimum gas. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200093d
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13056–13065[article] Influence of feed entry on the segregation of a binary mixture of solids in a continuous fast fluidized bed [texte imprimé] / K. Ganesh Palappan, Auteur ; P. S. T. Sai, Auteur . - 2012 . - pp. 13056–13065.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13056–13065
Mots-clés : Fast fluidized Résumé : Studies on the influence of feed entry on segregation using continuous fast fluidization is not clearly understood even though studies are available on the segregation of particles in continuous bubbling/turbulent fluidized beds. In the present study, four different feed inlet positions are selected and tested in a 69 mm ID and 3.65 m height continuous fast fluidized bed. The feed is a binary mixture of solid particles of the same size, but different density. The inimitable observations noticed at various feed locations on fluidization behavior with segregation is discussed. Change in the feed inlet height of the fluidized bed is reflected drastically on the compositions of top and bottom products. Disparate behavior of continuous fluidization is noticed at selected feed inlet positions. Operation is not stable due to either particle congestion in the feeding line or nonuniform discharge of solids from the fluidized bed when the feed inlet position is located close to distributor. Further an enhanced-feed inlet location created a particle’s cloud above the dense phase. Excess of feed inlet height transformed the binary mixture severance and freeboard height. The optimum operating gas velocity required for maximum separation of both species is identified at every feed entry for different feed rates. A unique feed entry location is recognized for maximum separation of both the species and minimum gas. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200093d Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Prediction of liquid – liquid equilibria for biofuel applications by quantum chemical calculations using the cosmo - SAC method Type de document : texte imprimé Auteurs : Mitesh R. Shah, Auteur ; Ganapati D. Yadav, Auteur Année de publication : 2012 Article en page(s) : pp. 13066-13075 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Phase equilibrium Liquid liquid Prediction Résumé : Currently, there is a great interest in the production of biofuels such as biodiesel, bioethanol and biobutanol. These processes involve liquid―liquid equilibria, which are important for the overall design of the process. However, suitable experimental data are often scarce. The Cosmo-SAC model provides a method to predict liquid―liquid equilibrium data from quantum chemical calculations without any experimental data. Hence, it can be used to provide initial estimates where experimental data are not available. In this work, we have evaluated the Cosmo-SAC model for the liquid―liquid equilibria involved in biodiesel production and bioalcohol extraction using ionic liquids, and we have compared it with the currently available experimental data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267464
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13066-13075[article] Prediction of liquid – liquid equilibria for biofuel applications by quantum chemical calculations using the cosmo - SAC method [texte imprimé] / Mitesh R. Shah, Auteur ; Ganapati D. Yadav, Auteur . - 2012 . - pp. 13066-13075.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13066-13075
Mots-clés : Phase equilibrium Liquid liquid Prediction Résumé : Currently, there is a great interest in the production of biofuels such as biodiesel, bioethanol and biobutanol. These processes involve liquid―liquid equilibria, which are important for the overall design of the process. However, suitable experimental data are often scarce. The Cosmo-SAC model provides a method to predict liquid―liquid equilibrium data from quantum chemical calculations without any experimental data. Hence, it can be used to provide initial estimates where experimental data are not available. In this work, we have evaluated the Cosmo-SAC model for the liquid―liquid equilibria involved in biodiesel production and bioalcohol extraction using ionic liquids, and we have compared it with the currently available experimental data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267464 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : The gibbs - duhem equation, the ideal gas mixture, and a generalized interpretation of dalton’s law Type de document : texte imprimé Auteurs : R. Ravi, Auteur Année de publication : 2012 Article en page(s) : pp. 13076–13082 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gibbs duhem equation Gas mixture Résumé : The ideas used by Gibbs in defining the ideal gas mixture are brought to light in view of their fundamental significance and the fact that they have not received due attention in the literature. Specifically, the central role played by the well-known Gibbs−Duhem equation in this regard is explained. The concept of a fundamental equation and its importance in the definition of an ideal gas as well as an ideal gas mixture is elucidated. The manner in which these ideas enabled Gibbs to give a very general interpretation of Dalton’s law is examined in detail. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101614s
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13076–13082[article] The gibbs - duhem equation, the ideal gas mixture, and a generalized interpretation of dalton’s law [texte imprimé] / R. Ravi, Auteur . - 2012 . - pp. 13076–13082.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13076–13082
Mots-clés : Gibbs duhem equation Gas mixture Résumé : The ideas used by Gibbs in defining the ideal gas mixture are brought to light in view of their fundamental significance and the fact that they have not received due attention in the literature. Specifically, the central role played by the well-known Gibbs−Duhem equation in this regard is explained. The concept of a fundamental equation and its importance in the definition of an ideal gas as well as an ideal gas mixture is elucidated. The manner in which these ideas enabled Gibbs to give a very general interpretation of Dalton’s law is examined in detail. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101614s Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Intensification of the dissolution of a sparingly soluble solid from a spinning disk in the presence of power ultrasound Type de document : texte imprimé Auteurs : D. Krishna Sandilya, Auteur ; A. Kannan, Auteur Année de publication : 2012 Article en page(s) : pp. 13083–13091 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Power ultrasound Résumé : The effect of power ultrasound (20 kHz) on the dissolution rates of a spinning disk made from sparingly soluble benzoic acid was investigated. Ultrasound was found to intensify the dissolution rates especially at lower rotational speeds of the spinning disk. The ultrasonic intensification was found to decrease with increase in the rotational speed of the spinning disk. Empirical correlation was developed for the Sherwood number in the presence of ultrasound and mechanical rotation of the disk. From this, the intensification factor was derived in terms of ultrasonic power input and Reynolds number corresponding to the spinning disk. The intensification factor obtained in the current spinning disk configuration was compared with that obtained for the rotating cylinder configuration studied by Kannan and Pathan [Kannan, A.; Pathan, S. K. Enhancement of Solid Dissolution Process. Chem. Eng. J.2004, 102, 45.]. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101702u
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13083–13091[article] Intensification of the dissolution of a sparingly soluble solid from a spinning disk in the presence of power ultrasound [texte imprimé] / D. Krishna Sandilya, Auteur ; A. Kannan, Auteur . - 2012 . - pp. 13083–13091.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13083–13091
Mots-clés : Power ultrasound Résumé : The effect of power ultrasound (20 kHz) on the dissolution rates of a spinning disk made from sparingly soluble benzoic acid was investigated. Ultrasound was found to intensify the dissolution rates especially at lower rotational speeds of the spinning disk. The ultrasonic intensification was found to decrease with increase in the rotational speed of the spinning disk. Empirical correlation was developed for the Sherwood number in the presence of ultrasound and mechanical rotation of the disk. From this, the intensification factor was derived in terms of ultrasonic power input and Reynolds number corresponding to the spinning disk. The intensification factor obtained in the current spinning disk configuration was compared with that obtained for the rotating cylinder configuration studied by Kannan and Pathan [Kannan, A.; Pathan, S. K. Enhancement of Solid Dissolution Process. Chem. Eng. J.2004, 102, 45.]. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101702u Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Modification of activated carbon fiber by metal dispersion and surface functionalization for the removal of 2 - chloroethanol Type de document : texte imprimé Auteurs : Mekala Bikshapathi, Auteur ; Susovan Mandal, Auteur ; Gyanesh N. Mathur, Auteur Année de publication : 2012 Article en page(s) : pp. 13092–13104 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon Fiber Chloroethanol Résumé : Nickel-impregnated phenolic resin precursor-based activated carbon fiber (ACF) was functionalized with pyridine and investigated for the adsorptive removal of 2-chloroethanol. Adsorption tests were carried out under flow conditions for different gas flow rates, solute concentrations, and temperatures in a perforated tubular adsorber. Various analytical and spectroscopic techniques, including X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and CHNSO elemental analysis, were used to characterize the adsorbents that have been prepared in this study. The results showed that the ACFs adsorbed significant amounts of 2-chloroethanol. Temperature had adverse effects on adsorption. At metallic concentrations in excess of 0.4 M of nickel, the formation of metal crystallites occurred, causing blockage of the pores and a decrease in the number of active metal sites. The functionalization of ACFs by pyridine was shown to produce a basic surface, resulting in the enhanced adsorption of the organic solute. The results have applications in the preparation of effective ACF-based adsorbents for controlling the emission of hazardous organic compounds. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101860e
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13092–13104[article] Modification of activated carbon fiber by metal dispersion and surface functionalization for the removal of 2 - chloroethanol [texte imprimé] / Mekala Bikshapathi, Auteur ; Susovan Mandal, Auteur ; Gyanesh N. Mathur, Auteur . - 2012 . - pp. 13092–13104.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13092–13104
Mots-clés : Carbon Fiber Chloroethanol Résumé : Nickel-impregnated phenolic resin precursor-based activated carbon fiber (ACF) was functionalized with pyridine and investigated for the adsorptive removal of 2-chloroethanol. Adsorption tests were carried out under flow conditions for different gas flow rates, solute concentrations, and temperatures in a perforated tubular adsorber. Various analytical and spectroscopic techniques, including X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and CHNSO elemental analysis, were used to characterize the adsorbents that have been prepared in this study. The results showed that the ACFs adsorbed significant amounts of 2-chloroethanol. Temperature had adverse effects on adsorption. At metallic concentrations in excess of 0.4 M of nickel, the formation of metal crystallites occurred, causing blockage of the pores and a decrease in the number of active metal sites. The functionalization of ACFs by pyridine was shown to produce a basic surface, resulting in the enhanced adsorption of the organic solute. The results have applications in the preparation of effective ACF-based adsorbents for controlling the emission of hazardous organic compounds. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101860e Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Drag on a sphere in poiseuille flow of shear - thinning power - law ffuids Type de document : texte imprimé Auteurs : Daoyun Song, Auteur ; Rakesh K. Gupta, Auteur Année de publication : 2012 Article en page(s) : pp. 13105–13115 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Poiseuille Flow Résumé : The effect of finite boundaries on the drag experienced by a sphere exposed to the Poiseuille flow of power-law fluids in cylindrical vessels has been investigated numerically. In particular, the momentum equations have been solved over the following ranges of conditions: sphere Reynolds number based on the area average velocity in the pipe, Re 1−100; power law index, n: 0.2−1, and sphere-to-tube diameter ratio, λ: 0−0.5. Due to the obstruction in the path of the fluid caused by the sphere fixed at the axis of the tube and the corresponding changes in the velocity field close to the sphere, there is extra viscous dissipation at the walls and this, in turn, leads to an increase in the drag force acting on the sphere. Conversely, there is an extra pressure drop caused by the fixed sphere for the flow of the fluid in the tube. The effect, however, is more significant at low Reynolds numbers than that at high Reynolds numbers. Similarly, the additional drag due to the confining walls increases with the increasing degree of obstruction, i.e., sphere-to-tube diameter ratio. Overall, all else being equal, the wall effect is seen to be less severe in power-law fluids than that in Newtonian fluids. Furthermore, the confining walls also influence the onset of flow separation and subsequently the size of the recirculation region. The present numerical predictions are consistent with the scant experimental results available in the literature for Newtonian and power-law fluids. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102120p
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13105–13115[article] Drag on a sphere in poiseuille flow of shear - thinning power - law ffuids [texte imprimé] / Daoyun Song, Auteur ; Rakesh K. Gupta, Auteur . - 2012 . - pp. 13105–13115.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13105–13115
Mots-clés : Poiseuille Flow Résumé : The effect of finite boundaries on the drag experienced by a sphere exposed to the Poiseuille flow of power-law fluids in cylindrical vessels has been investigated numerically. In particular, the momentum equations have been solved over the following ranges of conditions: sphere Reynolds number based on the area average velocity in the pipe, Re 1−100; power law index, n: 0.2−1, and sphere-to-tube diameter ratio, λ: 0−0.5. Due to the obstruction in the path of the fluid caused by the sphere fixed at the axis of the tube and the corresponding changes in the velocity field close to the sphere, there is extra viscous dissipation at the walls and this, in turn, leads to an increase in the drag force acting on the sphere. Conversely, there is an extra pressure drop caused by the fixed sphere for the flow of the fluid in the tube. The effect, however, is more significant at low Reynolds numbers than that at high Reynolds numbers. Similarly, the additional drag due to the confining walls increases with the increasing degree of obstruction, i.e., sphere-to-tube diameter ratio. Overall, all else being equal, the wall effect is seen to be less severe in power-law fluids than that in Newtonian fluids. Furthermore, the confining walls also influence the onset of flow separation and subsequently the size of the recirculation region. The present numerical predictions are consistent with the scant experimental results available in the literature for Newtonian and power-law fluids. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102120p Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Population balance modeling of environment dependent breakage : role of granular viscosity, density and compaction. model formulation and similarity analysis Type de document : texte imprimé Auteurs : Jayanta Chakraborty, Auteur ; Doraiswami Ramkrishna, Auteur Année de publication : 2012 Article en page(s) : pp. 13116–13128 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Similarity Compaction Density Viscosity Modeling Population balance Résumé : In this work, we introduce mechanistic considerations in nonlinear milling of particulate material. We show that the mobility of the powder can have a significant effect on the breakage frequency. During grinding, the change in particle size leads to changes in the mobility of the powder which in turn alters the breakage rate. The mechanistic modeling, being able to accommodate different responses of powder mobility for wet and dry grinding, is able to distinguish naturally between dry and wet grinding, an attribute not possessed by other nonlinear models. It is shown that the rich variety of phenomena observed in grinding mills emanates from the interplay between opposing factors that influence the breakage environment in a mill. Such factors include viscosity, density, and compaction of the powder. For dry grinding, the change in powder porosity and viscosity leads to a variety of nonlinear effects. For wet grinding the viscosity and density of the slurry impart a nonmonotonic variation in the breakage rate with particle size. A population balance equation (PBE) for environment dependent breakage has been formulated by considering the foregoing effects. Similarity analysis of the model equation shows the existence of self-similar behavior even for the environment dependent breakage. Experimental investigation of such self-similarity provides an effective diagnostic process for validating model framework. Furthermore, when combined with the methodology of solving inverse problems (e.g., Sathyagal, A. N.; Ramkrishna, D. Chem. Eng. Sci. 1996, 51, 1377), an effective approach becomes available for model identification. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267469
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13116–13128[article] Population balance modeling of environment dependent breakage : role of granular viscosity, density and compaction. model formulation and similarity analysis [texte imprimé] / Jayanta Chakraborty, Auteur ; Doraiswami Ramkrishna, Auteur . - 2012 . - pp. 13116–13128.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13116–13128
Mots-clés : Similarity Compaction Density Viscosity Modeling Population balance Résumé : In this work, we introduce mechanistic considerations in nonlinear milling of particulate material. We show that the mobility of the powder can have a significant effect on the breakage frequency. During grinding, the change in particle size leads to changes in the mobility of the powder which in turn alters the breakage rate. The mechanistic modeling, being able to accommodate different responses of powder mobility for wet and dry grinding, is able to distinguish naturally between dry and wet grinding, an attribute not possessed by other nonlinear models. It is shown that the rich variety of phenomena observed in grinding mills emanates from the interplay between opposing factors that influence the breakage environment in a mill. Such factors include viscosity, density, and compaction of the powder. For dry grinding, the change in powder porosity and viscosity leads to a variety of nonlinear effects. For wet grinding the viscosity and density of the slurry impart a nonmonotonic variation in the breakage rate with particle size. A population balance equation (PBE) for environment dependent breakage has been formulated by considering the foregoing effects. Similarity analysis of the model equation shows the existence of self-similar behavior even for the environment dependent breakage. Experimental investigation of such self-similarity provides an effective diagnostic process for validating model framework. Furthermore, when combined with the methodology of solving inverse problems (e.g., Sathyagal, A. N.; Ramkrishna, D. Chem. Eng. Sci. 1996, 51, 1377), an effective approach becomes available for model identification. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267469 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : pH and temperature stresses in bioreactor cultures : intracellular superoxide levels Type de document : texte imprimé Auteurs : Pritish Sarkar, Auteur ; G. K. Suraishkumar, Auteur Année de publication : 2012 Article en page(s) : pp. 13129–13136 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Bioreactor Résumé : Two of the most common stresses in natural environments, as well as in bioreactors, that are of importance in biofuel or bioterrorism contexts are pH and temperature stresses. Superoxide generation has been suspected as a possible reason for the effects of the above stresses, and superoxide is suspected to play a role in cell signaling. But, no information is available on a direct relationship between environmental stress and intracellular superoxide levels. We hypothesize that the exposure of cells to pH stress induces superoxide radicals, which leads to oxidative cellular damage, and thus it affects cells in culture. We tested the hypothesis on a model organism, Bacillus subtilis, which is well studied, and has relevance in biofuel and bioterrorism contexts. Bacillus subtilis cells were exposed to different pH-stress conditions (pH 5, 6, 8, or 9) and temperature-stress conditions (42, 45, 48, and 55 °C). Specific superoxide levels at pH 8 and 9 were 22% and 160%, respectively, higher than that of normal growth pH (pH 7), which was 6.48 ± 0.37 mmol (1012 live cells)−1. Superoxide generation due to pH stress has not been reported thus far in the literature. Although detection of superoxide induced by temperature stress has been reported, it has not been quantified. When Bacillus subtilis cells were exposed to 42, 45, 48, and 55 °C for 1 h, the specific intracellular superoxide levels were 52%, 150%, 220%, and 314%, respectively, higher than the value at normal growth temperature, 37 °C. The extent of intracellular lipid peroxidation was higher under the stressed conditions. The mechanism for alkaline pH-stress-induced superoxide generation seems to be the continuation of metabolic activities even though the growth is arrested. The mode of temperature-stress-mediated cell death is necrosis, and the extent of cell death is correlated with the specific intracellular superoxide level. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200081k?mi=qryllt&af=R&pageSize=20&searchT [...]
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13129–13136[article] pH and temperature stresses in bioreactor cultures : intracellular superoxide levels [texte imprimé] / Pritish Sarkar, Auteur ; G. K. Suraishkumar, Auteur . - 2012 . - pp. 13129–13136.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13129–13136
Mots-clés : Bioreactor Résumé : Two of the most common stresses in natural environments, as well as in bioreactors, that are of importance in biofuel or bioterrorism contexts are pH and temperature stresses. Superoxide generation has been suspected as a possible reason for the effects of the above stresses, and superoxide is suspected to play a role in cell signaling. But, no information is available on a direct relationship between environmental stress and intracellular superoxide levels. We hypothesize that the exposure of cells to pH stress induces superoxide radicals, which leads to oxidative cellular damage, and thus it affects cells in culture. We tested the hypothesis on a model organism, Bacillus subtilis, which is well studied, and has relevance in biofuel and bioterrorism contexts. Bacillus subtilis cells were exposed to different pH-stress conditions (pH 5, 6, 8, or 9) and temperature-stress conditions (42, 45, 48, and 55 °C). Specific superoxide levels at pH 8 and 9 were 22% and 160%, respectively, higher than that of normal growth pH (pH 7), which was 6.48 ± 0.37 mmol (1012 live cells)−1. Superoxide generation due to pH stress has not been reported thus far in the literature. Although detection of superoxide induced by temperature stress has been reported, it has not been quantified. When Bacillus subtilis cells were exposed to 42, 45, 48, and 55 °C for 1 h, the specific intracellular superoxide levels were 52%, 150%, 220%, and 314%, respectively, higher than the value at normal growth temperature, 37 °C. The extent of intracellular lipid peroxidation was higher under the stressed conditions. The mechanism for alkaline pH-stress-induced superoxide generation seems to be the continuation of metabolic activities even though the growth is arrested. The mode of temperature-stress-mediated cell death is necrosis, and the extent of cell death is correlated with the specific intracellular superoxide level. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200081k?mi=qryllt&af=R&pageSize=20&searchT [...] Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Effects of particle diameter and position on hydrodynamics around a confined sphere Type de document : texte imprimé Auteurs : Suresh Krishnan, Auteur ; Kannan Aravamudan, Auteur Année de publication : 2012 Article en page(s) : pp. 13137–13160 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrodynamics Résumé : The effect of confinement of a sphere within a tube on the hydrodynamics of Newtonian fluid flow around the solid surface is investigated. The ratio of particle diameter to tube diameter (blockage ratio), the ratio of sphere distance from the tube axis to the tube diameter (eccentricity), and the fluid flow rate were the parameters of this study. Computational fluid dynamics (CFD) simulations were carried out to obtain the flow field around the sphere from which the angle of boundary layer separations, as well as drag and lift coefficients, were obtained. The pressure distributions and friction factor along the sphere surface are also reported. To estimate the effect of confinement and eccentricity in position of the particle, with respect to the tube axis, the results are compared with the classical case involving the flow of an unbounded fluid over the sphere. The drag coefficient diminished when the particle was positioned eccentrically with respect to the tube axis at very low particle Reynolds number (Rep). However, the drag coefficient increased with increasing eccentric positions at higher Rep. At eccentric particle positions, boundary layer separation occurred earlier from the upper hemisphere while, depending on the eccentricity, it was delayed or nonexistent in the lower hemisphere. The difference in pressure between the lower and upper hemisphere regions led to incursion of fluid into the upper hemispherical region. Correlations are proposed for the drag and lift coefficients in the range of 0.1≤ Rep ≤ 500 for different possible eccentricities and blockage ratios. The results from this work will be of relevance in applications such as fluidization and aseptic food processing. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2000852
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13137–13160[article] Effects of particle diameter and position on hydrodynamics around a confined sphere [texte imprimé] / Suresh Krishnan, Auteur ; Kannan Aravamudan, Auteur . - 2012 . - pp. 13137–13160.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13137–13160
Mots-clés : Hydrodynamics Résumé : The effect of confinement of a sphere within a tube on the hydrodynamics of Newtonian fluid flow around the solid surface is investigated. The ratio of particle diameter to tube diameter (blockage ratio), the ratio of sphere distance from the tube axis to the tube diameter (eccentricity), and the fluid flow rate were the parameters of this study. Computational fluid dynamics (CFD) simulations were carried out to obtain the flow field around the sphere from which the angle of boundary layer separations, as well as drag and lift coefficients, were obtained. The pressure distributions and friction factor along the sphere surface are also reported. To estimate the effect of confinement and eccentricity in position of the particle, with respect to the tube axis, the results are compared with the classical case involving the flow of an unbounded fluid over the sphere. The drag coefficient diminished when the particle was positioned eccentrically with respect to the tube axis at very low particle Reynolds number (Rep). However, the drag coefficient increased with increasing eccentric positions at higher Rep. At eccentric particle positions, boundary layer separation occurred earlier from the upper hemisphere while, depending on the eccentricity, it was delayed or nonexistent in the lower hemisphere. The difference in pressure between the lower and upper hemisphere regions led to incursion of fluid into the upper hemispherical region. Correlations are proposed for the drag and lift coefficients in the range of 0.1≤ Rep ≤ 500 for different possible eccentricities and blockage ratios. The results from this work will be of relevance in applications such as fluidization and aseptic food processing. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2000852 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Influence of shear thinning on viscoelastic fluid – structure interaction in a two - dimensional collapsible channel Type de document : texte imprimé Auteurs : Debadi Chakraborty, Auteur ; J. Ravi Prakash, Auteur Année de publication : 2012 Article en page(s) : pp. 13161–13168 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Viscoelastic Fluid structure Résumé : We compute numerically the steady flow of a viscoelastic FENE-P fluid in a two-dimensional collapsible channel, in which a zero-thickness membrane under constant tension has replaced part of the top wall. This geometry has been studied extensively as a benchmark to examine fluid-structure interactions between a flowing Newtonian fluid and a deformable wall. The rheological behavior of the viscoelastic FENE-P fluid is described in terms of a conformation tensor model. The mesh equation and transport equations are discretized using the discrete elastic viscous stress split-traceless gradient (DEVSS-TG/SUPG) mixed finite-element method. The influence of viscoelasticity and shear thinning on flow patterns and stress profiles is examined, and comparisons with Newtonian predictions are reported. The existence of a limiting Weissenberg number beyond which computations fail is demonstrated. The extent of shear thinning is shown to be a key factor in determining the nature of the fluid-structure interaction. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200173b
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13161–13168[article] Influence of shear thinning on viscoelastic fluid – structure interaction in a two - dimensional collapsible channel [texte imprimé] / Debadi Chakraborty, Auteur ; J. Ravi Prakash, Auteur . - 2012 . - pp. 13161–13168.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13161–13168
Mots-clés : Viscoelastic Fluid structure Résumé : We compute numerically the steady flow of a viscoelastic FENE-P fluid in a two-dimensional collapsible channel, in which a zero-thickness membrane under constant tension has replaced part of the top wall. This geometry has been studied extensively as a benchmark to examine fluid-structure interactions between a flowing Newtonian fluid and a deformable wall. The rheological behavior of the viscoelastic FENE-P fluid is described in terms of a conformation tensor model. The mesh equation and transport equations are discretized using the discrete elastic viscous stress split-traceless gradient (DEVSS-TG/SUPG) mixed finite-element method. The influence of viscoelasticity and shear thinning on flow patterns and stress profiles is examined, and comparisons with Newtonian predictions are reported. The existence of a limiting Weissenberg number beyond which computations fail is demonstrated. The extent of shear thinning is shown to be a key factor in determining the nature of the fluid-structure interaction. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200173b Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Analysis of entropy generation due to natural convection in rhombic enclosures Type de document : texte imprimé Auteurs : R. Anandalakshmi, Auteur ; Tanmay Basak, Auteur Année de publication : 2012 Article en page(s) : pp. 13169–13189 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Entropy generation Résumé : One way of increasing the energy efficiency in thermal processing of materials is to reduce exergy losses due to irreversibilities, measured as “entropy generation”. In this study, an analysis of entropy generation during natural convection in rhombic enclosures with various inclination angles (φ = 30°, 45°, and 75°) has been carried out for the efficient thermal processing of various fluids (Prandtl numbers of Pr = 0.015, 0.7, 7.2, and 1000) in a range of Rayleigh numbers (Ra = 103–105). The enclosure is bounded by an adiabatic top wall, cold side walls, and an isothermally (case 1) and nonisothermally (case 2) heated bottom wall. Isotherms (θ), streamlines (ψ), and entropy generation contours due to heat transfer (Sθ) and fluid friction irreversibility (Sψ) are analyzed for both cases. At low Rayleigh number (Ra = 103), the entropy generation in the cavity is dominated by Sθ for all φ, irrespective of Pr. As Ra increases to 105, the fluid flow intensifies and Sψ also increases for all φ, irrespective of Pr. The total entropy generation (Stotal), average Bejan number (Beav), and average heat-transfer rate (Nub) are plotted for Rayleigh number ranges of 103 ≤ Ra ≤ 105. The total entropy generation (Stotal) is found to be low for φ = 30° and high for φ = 75° for all Pr values at Ra = 105. Analysis of variations of Beav with Ra for high-Pr fluids indicates that Sψ contributes significantly for increase in Stotal. It is also found that the largest heat-transfer rate (Nub) corresponds to minimum entropy generation (Stotal) for φ = 30° cavities at Ra = 105 with all Pr in case 1. The nonisothermal heating strategy (case 2) is energy efficient, because of its lower Stotal value, corresponding to low Nub, which is due to a lesser heating effect than case 1 for all φ. Overall, rhombic cavities with φ = 30° may be the optimal geometrical design for thermal processing of all types of fluids (Pr = 0.015, 0.7, 7.2, and 1000), irrespective of the heating strategy. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200184y
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13169–13189[article] Analysis of entropy generation due to natural convection in rhombic enclosures [texte imprimé] / R. Anandalakshmi, Auteur ; Tanmay Basak, Auteur . - 2012 . - pp. 13169–13189.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13169–13189
Mots-clés : Entropy generation Résumé : One way of increasing the energy efficiency in thermal processing of materials is to reduce exergy losses due to irreversibilities, measured as “entropy generation”. In this study, an analysis of entropy generation during natural convection in rhombic enclosures with various inclination angles (φ = 30°, 45°, and 75°) has been carried out for the efficient thermal processing of various fluids (Prandtl numbers of Pr = 0.015, 0.7, 7.2, and 1000) in a range of Rayleigh numbers (Ra = 103–105). The enclosure is bounded by an adiabatic top wall, cold side walls, and an isothermally (case 1) and nonisothermally (case 2) heated bottom wall. Isotherms (θ), streamlines (ψ), and entropy generation contours due to heat transfer (Sθ) and fluid friction irreversibility (Sψ) are analyzed for both cases. At low Rayleigh number (Ra = 103), the entropy generation in the cavity is dominated by Sθ for all φ, irrespective of Pr. As Ra increases to 105, the fluid flow intensifies and Sψ also increases for all φ, irrespective of Pr. The total entropy generation (Stotal), average Bejan number (Beav), and average heat-transfer rate (Nub) are plotted for Rayleigh number ranges of 103 ≤ Ra ≤ 105. The total entropy generation (Stotal) is found to be low for φ = 30° and high for φ = 75° for all Pr values at Ra = 105. Analysis of variations of Beav with Ra for high-Pr fluids indicates that Sψ contributes significantly for increase in Stotal. It is also found that the largest heat-transfer rate (Nub) corresponds to minimum entropy generation (Stotal) for φ = 30° cavities at Ra = 105 with all Pr in case 1. The nonisothermal heating strategy (case 2) is energy efficient, because of its lower Stotal value, corresponding to low Nub, which is due to a lesser heating effect than case 1 for all φ. Overall, rhombic cavities with φ = 30° may be the optimal geometrical design for thermal processing of all types of fluids (Pr = 0.015, 0.7, 7.2, and 1000), irrespective of the heating strategy. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200184y Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Constitutive models for filtered two - fluid models of fluidized gas – particle flows Type de document : texte imprimé Auteurs : Yesim Igci, Auteur ; Sankaran Sundaresan, Auteur Année de publication : 2012 Article en page(s) : pp. 13190–13201 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas Particle flows Résumé : Our prior study [Igci et al., AIChE J., 2008, 54, 1431–1448] presented a methodology where computational results obtained through highly resolved simulations of a given microscopic two-fluid model (TFM) for gas-particle flows are filtered to deduce models for the residual correlations appearing in the corresponding filtered TFM equations that are appropriate for coarse-grid simulations of gas-particle flows. In the present study, we have performed a large number of highly resolved simulations of a kinetic theory based TFM in two- and three-dimensional periodic domains using this methodology and filtered the results to generate computational data on the filtered drag coefficient, the filtered particle phase pressure, and the filtered particle phase viscosity. These results have been captured in the form of correlations that can readily be employed in coarse-grid simulations of gas-particle flows. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200190q
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13190–13201[article] Constitutive models for filtered two - fluid models of fluidized gas – particle flows [texte imprimé] / Yesim Igci, Auteur ; Sankaran Sundaresan, Auteur . - 2012 . - pp. 13190–13201.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13190–13201
Mots-clés : Gas Particle flows Résumé : Our prior study [Igci et al., AIChE J., 2008, 54, 1431–1448] presented a methodology where computational results obtained through highly resolved simulations of a given microscopic two-fluid model (TFM) for gas-particle flows are filtered to deduce models for the residual correlations appearing in the corresponding filtered TFM equations that are appropriate for coarse-grid simulations of gas-particle flows. In the present study, we have performed a large number of highly resolved simulations of a kinetic theory based TFM in two- and three-dimensional periodic domains using this methodology and filtered the results to generate computational data on the filtered drag coefficient, the filtered particle phase pressure, and the filtered particle phase viscosity. These results have been captured in the form of correlations that can readily be employed in coarse-grid simulations of gas-particle flows. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200190q Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : A mechanism for the occurrence of ions in distilled water Type de document : texte imprimé Auteurs : Ramesh Balakrishnan, Auteur ; Ravi Sankannavar, Auteur ; K. Kesava Rao, Auteur Année de publication : 2012 Article en page(s) : pp. 13202–13209 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ions water Solar distillation Résumé : Solar distillation can be used to produce potable water from contaminated water. However, studies show that ions such as F– and NO3– occur in distillates from solar stills. In order to understand the reasons for this behavior, imaging and distillation experiments were conducted. White dots were seen in the vapor space above the interface of hot water poured into containers. The concentrations of various ions such as F– and SO42– in the distillates from thermal and solar distillation experiments were roughly comparable when the feed consisted of deionized water and also solutions having fluoride concentrations of 100 and 10 000 mg/L. These observations suggest that aerosols enter the distillation setup through leaks and provide nuclei for the condensation of water vapor. The water-soluble component of aerosols dissolves in the drops formed, and some of the drops are transferred to the distillate by buoyancy-driven convection. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2002022
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13202–13209[article] A mechanism for the occurrence of ions in distilled water [texte imprimé] / Ramesh Balakrishnan, Auteur ; Ravi Sankannavar, Auteur ; K. Kesava Rao, Auteur . - 2012 . - pp. 13202–13209.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13202–13209
Mots-clés : Ions water Solar distillation Résumé : Solar distillation can be used to produce potable water from contaminated water. However, studies show that ions such as F– and NO3– occur in distillates from solar stills. In order to understand the reasons for this behavior, imaging and distillation experiments were conducted. White dots were seen in the vapor space above the interface of hot water poured into containers. The concentrations of various ions such as F– and SO42– in the distillates from thermal and solar distillation experiments were roughly comparable when the feed consisted of deionized water and also solutions having fluoride concentrations of 100 and 10 000 mg/L. These observations suggest that aerosols enter the distillation setup through leaks and provide nuclei for the condensation of water vapor. The water-soluble component of aerosols dissolves in the drops formed, and some of the drops are transferred to the distillate by buoyancy-driven convection. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2002022 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Investigation of high - frequency, high - intensity ultrasonics for size reduction and washing of coal in aqueous medium Type de document : texte imprimé Auteurs : B. Ambedkar, Auteur ; R. Nagarajan, Auteur ; Jayanti, S., Auteur Année de publication : 2012 Article en page(s) : pp. 13210-13219 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Aqueous medium Coal Washing Résumé : While ultrasonic coal-wash is not entirely new in many countries, it has not yet been practiced in India, though it would appear that the relatively high-ash content of Indian coals would render them particularly suitable for such a washing procedure. In this study, state-of-the-art ultrasonic equipment, spanning the frequency range from highly cavitational ( 100 kHz), were used. The coal to be studied was received from Giral mine, Rajasthan, India. Four stages for ultrasound assisted coal particle breakage have been proposed and characterized with SEM images of sonicated coal. Sono-treatment, followed by the decanting process, has been found to remove detached ash effectively. Decanted coal samples were analyzed by SEM/EDX to determine the mechanism of ash removal by sonication. The present investigation also encompasses aqueous-based ultrasonic coal desulfurization. Ultrasound in aqueous medium produces OH, H2O2, HO2, O2, and ozone, which are strong oxidizing agents. The oxidation occurring in the presence of ultrasound is called αadvanced oxidation process", and this converts the sulfur present in the coal to water-soluble sulfates, thereby enhancing sulfur removal. Larger-scale trials with high-ash and sulfur coals are strongly recommended. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267476
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13210-13219[article] Investigation of high - frequency, high - intensity ultrasonics for size reduction and washing of coal in aqueous medium [texte imprimé] / B. Ambedkar, Auteur ; R. Nagarajan, Auteur ; Jayanti, S., Auteur . - 2012 . - pp. 13210-13219.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13210-13219
Mots-clés : Aqueous medium Coal Washing Résumé : While ultrasonic coal-wash is not entirely new in many countries, it has not yet been practiced in India, though it would appear that the relatively high-ash content of Indian coals would render them particularly suitable for such a washing procedure. In this study, state-of-the-art ultrasonic equipment, spanning the frequency range from highly cavitational ( 100 kHz), were used. The coal to be studied was received from Giral mine, Rajasthan, India. Four stages for ultrasound assisted coal particle breakage have been proposed and characterized with SEM images of sonicated coal. Sono-treatment, followed by the decanting process, has been found to remove detached ash effectively. Decanted coal samples were analyzed by SEM/EDX to determine the mechanism of ash removal by sonication. The present investigation also encompasses aqueous-based ultrasonic coal desulfurization. Ultrasound in aqueous medium produces OH, H2O2, HO2, O2, and ozone, which are strong oxidizing agents. The oxidation occurring in the presence of ultrasound is called αadvanced oxidation process", and this converts the sulfur present in the coal to water-soluble sulfates, thereby enhancing sulfur removal. Larger-scale trials with high-ash and sulfur coals are strongly recommended. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267476 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Experimental and computational investigation of two phase gas — liquid flows : point source injection at the center Type de document : texte imprimé Auteurs : Ashraf Ali, Auteur ; S. Pushpavanam, Auteur Année de publication : 2012 Article en page(s) : pp. 13220-13229 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Point source Two phase flow Gas liquid Résumé : In this work, an experimental and numerical investigation ofhydrodynamics in a liquid induced by a bubble plume is carried out. The gas is introduced through a needle in the center of the tank containing water. The gas―liquid flow in such systems is inherently unsteady. Particle image velocimetry (PIV) was used to experimentally determine the transient velocity fields in the system. For this gas―liquid flow system, both the fluctuating and mean liquid velocities were determined experimentally by 2D and 3D PIV. The system was investigated for a liquid phase Reynolds number in the range of 3.7 × 104 to 1.8 × 105 and bubble phase Reynolds number in the range from 2350 to 11773. The behavior of the system was simulated in FLUENT 6.3.26 using a two fluid Euler―Lagrangian (EL) model with a constant bubble size of 5 mm. Here, water is treated as the continuous phase, and gas bubbles are treated as the dispersed phase. Motion of the bubbles renders the flow turbulent, and this effect is captured by the standard k―ε turbulence model. The temporal prediction of the flow field is compared with experimental results obtained from 2D and 3D measurements. The predictions from the 3D simulations capture the oscillating behavior found using 3D PIV. The 2D simulations predict a significantly higher value of turbulent viscosity. This is hypothesized as the reason as to why these simulations do not capture the oscillating behavior. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267477
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13220-13229[article] Experimental and computational investigation of two phase gas — liquid flows : point source injection at the center [texte imprimé] / Ashraf Ali, Auteur ; S. Pushpavanam, Auteur . - 2012 . - pp. 13220-13229.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13220-13229
Mots-clés : Point source Two phase flow Gas liquid Résumé : In this work, an experimental and numerical investigation ofhydrodynamics in a liquid induced by a bubble plume is carried out. The gas is introduced through a needle in the center of the tank containing water. The gas―liquid flow in such systems is inherently unsteady. Particle image velocimetry (PIV) was used to experimentally determine the transient velocity fields in the system. For this gas―liquid flow system, both the fluctuating and mean liquid velocities were determined experimentally by 2D and 3D PIV. The system was investigated for a liquid phase Reynolds number in the range of 3.7 × 104 to 1.8 × 105 and bubble phase Reynolds number in the range from 2350 to 11773. The behavior of the system was simulated in FLUENT 6.3.26 using a two fluid Euler―Lagrangian (EL) model with a constant bubble size of 5 mm. Here, water is treated as the continuous phase, and gas bubbles are treated as the dispersed phase. Motion of the bubbles renders the flow turbulent, and this effect is captured by the standard k―ε turbulence model. The temporal prediction of the flow field is compared with experimental results obtained from 2D and 3D measurements. The predictions from the 3D simulations capture the oscillating behavior found using 3D PIV. The 2D simulations predict a significantly higher value of turbulent viscosity. This is hypothesized as the reason as to why these simulations do not capture the oscillating behavior. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267477 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Liquid – liquid mixing in coiled flow inverter Type de document : texte imprimé Auteurs : Monisha Mridha Mandal, Auteur ; Palka Aggarwal, Auteur ; K. D. P. Nigam, Auteur Année de publication : 2012 Article en page(s) : pp. 13230-13235 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mixing Résumé : The mixing of liquids is a common operation in process industries such as refineries and chemical and pharmaceutical industries, etc. However, the problem of mixing of different liquids has not been rigorously characterized. Therefore, the objective of this paper is to investigate liquid―liquid mixing in a novel coiled flow inverter (CFI). The device works on the principle of flow inversion which is achieved by bending a coiled tube to 90° at equidistant length. In the present study, velocity field and scalar concentration distribution of liquids were characterized. The mixing performances and pressure drop in CFI was investigated and compared with that of a straight, coiled tube and helical element mixer (HEM) for a liquid flow range of 98 ≤ Re ≤ 1020. CFI exhibits significant mixing of two liquids with negligible change in pressure drop as compared to a coiled tube as well as a HEM. The present study reveals that CFI is an efficient device for the mixing of two liquids in process industries. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267478
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13230-13235[article] Liquid – liquid mixing in coiled flow inverter [texte imprimé] / Monisha Mridha Mandal, Auteur ; Palka Aggarwal, Auteur ; K. D. P. Nigam, Auteur . - 2012 . - pp. 13230-13235.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13230-13235
Mots-clés : Mixing Résumé : The mixing of liquids is a common operation in process industries such as refineries and chemical and pharmaceutical industries, etc. However, the problem of mixing of different liquids has not been rigorously characterized. Therefore, the objective of this paper is to investigate liquid―liquid mixing in a novel coiled flow inverter (CFI). The device works on the principle of flow inversion which is achieved by bending a coiled tube to 90° at equidistant length. In the present study, velocity field and scalar concentration distribution of liquids were characterized. The mixing performances and pressure drop in CFI was investigated and compared with that of a straight, coiled tube and helical element mixer (HEM) for a liquid flow range of 98 ≤ Re ≤ 1020. CFI exhibits significant mixing of two liquids with negligible change in pressure drop as compared to a coiled tube as well as a HEM. The present study reveals that CFI is an efficient device for the mixing of two liquids in process industries. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267478 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Chemical engineering at the cellular scale : cellular signal processing Type de document : texte imprimé Auteurs : J. Krishnan, Auteur Année de publication : 2012 Article en page(s) : pp. 13236–13243 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cellular processes signal Résumé : There has been a considerable effort in the past decade to understand different aspects of cellular processes from both a reverse engineering and, more recently, a synthetic perspective. In this article I provide a perspective on aspects of cellular signal processing which involve traditional chemical engineering elements (reactions, transport, control) and their variants, along with additional ingredients, sometimes combined in unusual ways. I also compare and contrast certain basic aspects of chemical engineering and cellular signal processing in areas of mutual overlap. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200323p
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13236–13243[article] Chemical engineering at the cellular scale : cellular signal processing [texte imprimé] / J. Krishnan, Auteur . - 2012 . - pp. 13236–13243.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13236–13243
Mots-clés : Cellular processes signal Résumé : There has been a considerable effort in the past decade to understand different aspects of cellular processes from both a reverse engineering and, more recently, a synthetic perspective. In this article I provide a perspective on aspects of cellular signal processing which involve traditional chemical engineering elements (reactions, transport, control) and their variants, along with additional ingredients, sometimes combined in unusual ways. I also compare and contrast certain basic aspects of chemical engineering and cellular signal processing in areas of mutual overlap. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200323p Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Effect of domain perturbations on the critical condition for steady - state thermal explosions Type de document : texte imprimé Auteurs : W. R. Batson, Auteur ; L. E. Johns, Auteur ; R. Narayanan, Auteur Année de publication : 2012 Article en page(s) : pp. 13244-13249 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermal explosion Steady state Critical conditions Résumé : A region heated by a temperature-dependent source is said to be stable if the heat conducted to the surroundings can balance the heat generated in the region. The critical value of the Frank-Kamenetskii number gives the limit of stability, the point at which a steady temperature field is no longer possible. Assuming that the critical Frank-Kamenetskii number can be obtained for a symmetric region where the problem is one-dimensional, we present a method for determining how it changes as the region is displaced into a less-symmetric region. We find that the displacement can be either stabilizing or destabilizing. The case of exponential heat generation is fairly well-predicted by the case of linear heat generation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267480
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13244-13249[article] Effect of domain perturbations on the critical condition for steady - state thermal explosions [texte imprimé] / W. R. Batson, Auteur ; L. E. Johns, Auteur ; R. Narayanan, Auteur . - 2012 . - pp. 13244-13249.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13244-13249
Mots-clés : Thermal explosion Steady state Critical conditions Résumé : A region heated by a temperature-dependent source is said to be stable if the heat conducted to the surroundings can balance the heat generated in the region. The critical value of the Frank-Kamenetskii number gives the limit of stability, the point at which a steady temperature field is no longer possible. Assuming that the critical Frank-Kamenetskii number can be obtained for a symmetric region where the problem is one-dimensional, we present a method for determining how it changes as the region is displaced into a less-symmetric region. We find that the displacement can be either stabilizing or destabilizing. The case of exponential heat generation is fairly well-predicted by the case of linear heat generation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267480 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Stabilizing the interface in the rayleigh – taylor and the saffman – taylor problems by heating Type de document : texte imprimé Auteurs : Kamuran E. Uguz, Auteur ; Lewis E. Johns, Auteur ; Ranga Narayanan, Auteur Année de publication : 2012 Article en page(s) : pp. 13250-13257 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Heating Résumé : We can stabilize the Rayleigh―Taylor instability to perturbations of any wavelength by heating from above. The same is true for the Saffinan―Taylor instability. We present formulas for estimating the temperature difference required to do this and find that more reasonable temperature differences obtain in the Saffman―Taylor problem because the temperature dependence of the viscosity is much stronger than the temperature dependence of the density. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267481
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13250-13257[article] Stabilizing the interface in the rayleigh – taylor and the saffman – taylor problems by heating [texte imprimé] / Kamuran E. Uguz, Auteur ; Lewis E. Johns, Auteur ; Ranga Narayanan, Auteur . - 2012 . - pp. 13250-13257.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13250-13257
Mots-clés : Heating Résumé : We can stabilize the Rayleigh―Taylor instability to perturbations of any wavelength by heating from above. The same is true for the Saffinan―Taylor instability. We present formulas for estimating the temperature difference required to do this and find that more reasonable temperature differences obtain in the Saffman―Taylor problem because the temperature dependence of the viscosity is much stronger than the temperature dependence of the density. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267481 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Celerity - amplitude relations for solitary waves on vertically falling films Type de document : texte imprimé Auteurs : Cesar E. Meza, Auteur ; Vemuri Balakotaiah, Auteur Année de publication : 2012 Article en page(s) : pp. 13258–13272 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Celerity solitary waves Résumé : Experimental data relating the amplitude and celerity of solitary waves on vertically falling and naturally excited films are presented over a wide of range of fluid properties and flow rates (2 DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2005803
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13258–13272[article] Celerity - amplitude relations for solitary waves on vertically falling films [texte imprimé] / Cesar E. Meza, Auteur ; Vemuri Balakotaiah, Auteur . - 2012 . - pp. 13258–13272.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13258–13272
Mots-clés : Celerity solitary waves Résumé : Experimental data relating the amplitude and celerity of solitary waves on vertically falling and naturally excited films are presented over a wide of range of fluid properties and flow rates (2 DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2005803 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Effect of calcination temperature on catalytic hydrolysis of COS over CoNiAl catalysts derived from hydrotalcite precursor Type de document : texte imprimé Auteurs : Honghong Yi, Auteur ; Hongyan Wang, Auteur ; Xiaolong Tang, Auteur Année de publication : 2012 Article en page(s) : pp. 13273-13279 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Precursor Catalyst Hydrolysis Catalytic reaction Calcining Résumé : A series of CoNiAl composite oxide catalysts were prepared by calcining the CoNiAl hydrotalcite-like precursor at various temperatures and used in the catalytic hydrolysis of carbonyl sulfide (COS). The raw CoNiAl precursor and calcined products were characterized by various technologies. The catalyst calcined at 350 °C showed excellent activity and stability for COS hydrolysis at 50 °C and GHSV of 2000 h―1 with temperature of water saturator of 25 °C. The CoNiAl precursor was decomposed at 350 °C to form NiO accompanying spinel phase and hydroxyl groups (OH―), which were active sites of the hydrolysis of COS. With lower calcination temperature, the precursor is incompletely decomposed to form mixed oxides, thereby decreasing the catalyst activity. Increasing the calcination temperature above 350 °C led to severe sintering of NiO and other active components, causing decrease in the number of active sites. The deactivation of catalysts was also investigated. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267483
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13273-13279[article] Effect of calcination temperature on catalytic hydrolysis of COS over CoNiAl catalysts derived from hydrotalcite precursor [texte imprimé] / Honghong Yi, Auteur ; Hongyan Wang, Auteur ; Xiaolong Tang, Auteur . - 2012 . - pp. 13273-13279.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13273-13279
Mots-clés : Precursor Catalyst Hydrolysis Catalytic reaction Calcining Résumé : A series of CoNiAl composite oxide catalysts were prepared by calcining the CoNiAl hydrotalcite-like precursor at various temperatures and used in the catalytic hydrolysis of carbonyl sulfide (COS). The raw CoNiAl precursor and calcined products were characterized by various technologies. The catalyst calcined at 350 °C showed excellent activity and stability for COS hydrolysis at 50 °C and GHSV of 2000 h―1 with temperature of water saturator of 25 °C. The CoNiAl precursor was decomposed at 350 °C to form NiO accompanying spinel phase and hydroxyl groups (OH―), which were active sites of the hydrolysis of COS. With lower calcination temperature, the precursor is incompletely decomposed to form mixed oxides, thereby decreasing the catalyst activity. Increasing the calcination temperature above 350 °C led to severe sintering of NiO and other active components, causing decrease in the number of active sites. The deactivation of catalysts was also investigated. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267483 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Novel interpenetrating polymer network hydrogel microspheres of chitosan and poly (acrylamide) - grafted - guar gum for controlled release of ciprofloxacin Type de document : texte imprimé Auteurs : Praveen B. Kajjari, Auteur ; Lata S. Manjeshwar, Auteur ; Tejraj M. Aminabhavi, Auteur Année de publication : 2012 Article en page(s) : pp. 13280–13287 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymer Hydrogel Microspheres Résumé : Acrylamide-grafted-guar gum (pAAm-g-GG) was prepared and blended with chitosan (CS) to form interpenetrating polymer network (IPN) hydrogel microspheres by the emulsion cross-linking method using glutaraldehyde (GA) as a cross-linker. The microspheres encapsulated up to 74% of ciprofloxacin (CFX), an antibiotic drug, having a plasma half-life of 4 h and the release of CFX was extended up to 12 h. Scanning electron microscopy (SEM) confirmed their spherical structure with smooth surfaces; Fourier transform infrared spectroscopy (FTIR) confirmed the grafting reaction as well as chemical stability of CFX in the blend IPN hydrogel microspheres. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques confirmed the molecular level dispersion of CFX in the matrix. Swelling of microspheres performed in pH 7.4 buffer media was used to understand the drug release kinetics. In vitro release of CFX in pH 1.2 and 7.4 media showed a dependence on blend composition of the IPN, extent of cross-linking as well as initial drug loading. In vitro release data was analyzed using empirical equations, namely, Korsmeyer–Peppas, to compute the diffusion exponent (n), whose value ranged between 0.19 and 0.33, indicating non-Fickian transport of CFX through the blend IPN hydrogel microspheres. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2012856
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13280–13287[article] Novel interpenetrating polymer network hydrogel microspheres of chitosan and poly (acrylamide) - grafted - guar gum for controlled release of ciprofloxacin [texte imprimé] / Praveen B. Kajjari, Auteur ; Lata S. Manjeshwar, Auteur ; Tejraj M. Aminabhavi, Auteur . - 2012 . - pp. 13280–13287.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13280–13287
Mots-clés : Polymer Hydrogel Microspheres Résumé : Acrylamide-grafted-guar gum (pAAm-g-GG) was prepared and blended with chitosan (CS) to form interpenetrating polymer network (IPN) hydrogel microspheres by the emulsion cross-linking method using glutaraldehyde (GA) as a cross-linker. The microspheres encapsulated up to 74% of ciprofloxacin (CFX), an antibiotic drug, having a plasma half-life of 4 h and the release of CFX was extended up to 12 h. Scanning electron microscopy (SEM) confirmed their spherical structure with smooth surfaces; Fourier transform infrared spectroscopy (FTIR) confirmed the grafting reaction as well as chemical stability of CFX in the blend IPN hydrogel microspheres. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques confirmed the molecular level dispersion of CFX in the matrix. Swelling of microspheres performed in pH 7.4 buffer media was used to understand the drug release kinetics. In vitro release of CFX in pH 1.2 and 7.4 media showed a dependence on blend composition of the IPN, extent of cross-linking as well as initial drug loading. In vitro release data was analyzed using empirical equations, namely, Korsmeyer–Peppas, to compute the diffusion exponent (n), whose value ranged between 0.19 and 0.33, indicating non-Fickian transport of CFX through the blend IPN hydrogel microspheres. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2012856 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Thorium (IV) removal and recovery from aqueous solutions using tannin - modified poly (glycidylmethacrylate) - grafted zirconium oxide densified cellulose Type de document : texte imprimé Auteurs : Thayyath S. Anirudhan, Auteur ; Sylaja R. Rejeena, Auteur Année de publication : 2012 Article en page(s) : pp. 13288-13298 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Aqueous solution Résumé : A novel adsorbent, tannin-modified poly(glycidylmethacrylate)-grafted zirconium oxide-densified cellulose (TMPGZDC) was synthesized by graft copolymerization reaction of glycidylmethacrylate onto zirconium oxide densified cellulose (ZDC) in the presence of N,N'-methylenebuacrylamide as cross-linker followed by tannin immobilization, and well characterized. The adsorption efficiency of TMPGZDC toward thorium(IV) from aqueous solutions was studied at different optimized conditions. The optimum pH for maximum adsorption was found to be 5.5 with the adsorption percentage of99.2% for an initial concentration of 10 mg/L Equilibrium was achieved within 2 h. The kinetic data were found to follow pseudo-second-order model, which assumes the presence of chemisorption. The temperature dependence indicates an exothermic process. The well agreement of equilibrium data with Langmuir isotherm and Redlich-Peterson isotherm models confirms the monolayer coverage of Th(IV) onto TMPGZDC surface and the maximum adsorption capacity was found to be 96.7 mg/g. Complete removal of Th(IV) from simulated seawater was possible with an adsorbent dosage of 3.0 g/L. Spent adsorbent was effectively degenerated with 0.1 M HNO3. The present investigation shows that TMPGZDC is a promising adsorbent for the removal and recovery of Th(IV) from aqueous solutions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267485
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13288-13298[article] Thorium (IV) removal and recovery from aqueous solutions using tannin - modified poly (glycidylmethacrylate) - grafted zirconium oxide densified cellulose [texte imprimé] / Thayyath S. Anirudhan, Auteur ; Sylaja R. Rejeena, Auteur . - 2012 . - pp. 13288-13298.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13288-13298
Mots-clés : Aqueous solution Résumé : A novel adsorbent, tannin-modified poly(glycidylmethacrylate)-grafted zirconium oxide-densified cellulose (TMPGZDC) was synthesized by graft copolymerization reaction of glycidylmethacrylate onto zirconium oxide densified cellulose (ZDC) in the presence of N,N'-methylenebuacrylamide as cross-linker followed by tannin immobilization, and well characterized. The adsorption efficiency of TMPGZDC toward thorium(IV) from aqueous solutions was studied at different optimized conditions. The optimum pH for maximum adsorption was found to be 5.5 with the adsorption percentage of99.2% for an initial concentration of 10 mg/L Equilibrium was achieved within 2 h. The kinetic data were found to follow pseudo-second-order model, which assumes the presence of chemisorption. The temperature dependence indicates an exothermic process. The well agreement of equilibrium data with Langmuir isotherm and Redlich-Peterson isotherm models confirms the monolayer coverage of Th(IV) onto TMPGZDC surface and the maximum adsorption capacity was found to be 96.7 mg/g. Complete removal of Th(IV) from simulated seawater was possible with an adsorbent dosage of 3.0 g/L. Spent adsorbent was effectively degenerated with 0.1 M HNO3. The present investigation shows that TMPGZDC is a promising adsorbent for the removal and recovery of Th(IV) from aqueous solutions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267485 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Synthesis and UV Absorption Properties of Aurintricarboxylic Acid Intercalated Zn–Al Layered Double Hydroxides Type de document : texte imprimé Auteurs : Haifeng Zhu, Auteur ; Yongjun Feng, Auteur ; Pinggui Tang, Auteur Année de publication : 2012 Article en page(s) : pp. 13299–13303 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ultraviolet radiation Résumé : Aurintricarboxylic acid (ATA), a UV absorbent, has successfully been intercalated into the interlayer spacing of Zn-Al-NO3LDHs precursor through an anion-exchange reaction. The structure and the thermal- and photostability of the intercalated product were investigated by various techniques such as powder X-ray diffraction (XRD), infrared spectroscopy (FT-IR), thermogravimetry and differential thermal analysis (TG―DTA), and UV―vis spectroscopy. The increase of the basal spacing from 0.90 to 1.52 nm as observed by XRD suggests that the ATA anions have replaced the NO3― anions in the interlayer region of the precursor LDHs. The results of infrared spectroscopy and thermogravimetry and differential thermal analysis (TG―DTA) also reveal the presence of supramolecular host—guest interactions between the brucite-like sheet and the intercalated ATA anions. The intercalation of the ATA anions into the LDHs markedly enhances the thermal stability of this UV absorbent After incorporation of 1 wt % ZnAl-ATA-LDHs to polypropylene (PP), also, the resulted ZnAl-ATA-LDHs/PP composite has much higher resistance to UV degradation related to PP. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267486
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13299–13303[article] Synthesis and UV Absorption Properties of Aurintricarboxylic Acid Intercalated Zn–Al Layered Double Hydroxides [texte imprimé] / Haifeng Zhu, Auteur ; Yongjun Feng, Auteur ; Pinggui Tang, Auteur . - 2012 . - pp. 13299–13303.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13299–13303
Mots-clés : Ultraviolet radiation Résumé : Aurintricarboxylic acid (ATA), a UV absorbent, has successfully been intercalated into the interlayer spacing of Zn-Al-NO3LDHs precursor through an anion-exchange reaction. The structure and the thermal- and photostability of the intercalated product were investigated by various techniques such as powder X-ray diffraction (XRD), infrared spectroscopy (FT-IR), thermogravimetry and differential thermal analysis (TG―DTA), and UV―vis spectroscopy. The increase of the basal spacing from 0.90 to 1.52 nm as observed by XRD suggests that the ATA anions have replaced the NO3― anions in the interlayer region of the precursor LDHs. The results of infrared spectroscopy and thermogravimetry and differential thermal analysis (TG―DTA) also reveal the presence of supramolecular host—guest interactions between the brucite-like sheet and the intercalated ATA anions. The intercalation of the ATA anions into the LDHs markedly enhances the thermal stability of this UV absorbent After incorporation of 1 wt % ZnAl-ATA-LDHs to polypropylene (PP), also, the resulted ZnAl-ATA-LDHs/PP composite has much higher resistance to UV degradation related to PP. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267486 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Packed - bed catalytic cracking of oak - derived pyrolytic vapors Type de document : texte imprimé Auteurs : David J. Mihalcik, Auteur ; Akwasi A. Boateng, Auteur ; Charles A. Mullen, Auteur Année de publication : 2012 Article en page(s) : pp. 13304–13312 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic Pyrolysis vapors Résumé : Catalytic upgrading of pyrolysis vapors derived from oak was carried out using a fixed-bed catalytic column at 425 °C. The vapors were drawn by splitting a fraction from the full stream of vapors produced at 500 °C in a 5 kg/h bench-scale fast pyrolysis reactor system downstream from the cyclone separator. The placement of the fixed-bed column was varied within the condenser train to determine the effect of temperature, residual water, solids, and oxygenated components of the approach vapor stream on the upgraded product quality. The upgraded liquid was collected by immediate contact with a dry ice acetone bath, complimented by a secondary collection system comprised of a methanol spray condenser. Quantitative gas chromatography/mass spectroscopy (GC/MS) analysis of the recovered liquid showed a substantial decrease of oxygen-containing species with a significant increase in carbon-rich (≥C6) aromatic hydrocarbons. The extent of deoxygenation was location-specific and dependent upon temperature and the relative concentrations of water, oxygenates, and residual solids in the approach vapor. The study provides the engineering practicality to catalytic vapor upgrading and offers the necessary data for the design and optimization of a full-stream upgrading of pyrolysis oils via in situ vapor cracking. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201831e
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13304–13312[article] Packed - bed catalytic cracking of oak - derived pyrolytic vapors [texte imprimé] / David J. Mihalcik, Auteur ; Akwasi A. Boateng, Auteur ; Charles A. Mullen, Auteur . - 2012 . - pp. 13304–13312.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13304–13312
Mots-clés : Catalytic Pyrolysis vapors Résumé : Catalytic upgrading of pyrolysis vapors derived from oak was carried out using a fixed-bed catalytic column at 425 °C. The vapors were drawn by splitting a fraction from the full stream of vapors produced at 500 °C in a 5 kg/h bench-scale fast pyrolysis reactor system downstream from the cyclone separator. The placement of the fixed-bed column was varied within the condenser train to determine the effect of temperature, residual water, solids, and oxygenated components of the approach vapor stream on the upgraded product quality. The upgraded liquid was collected by immediate contact with a dry ice acetone bath, complimented by a secondary collection system comprised of a methanol spray condenser. Quantitative gas chromatography/mass spectroscopy (GC/MS) analysis of the recovered liquid showed a substantial decrease of oxygen-containing species with a significant increase in carbon-rich (≥C6) aromatic hydrocarbons. The extent of deoxygenation was location-specific and dependent upon temperature and the relative concentrations of water, oxygenates, and residual solids in the approach vapor. The study provides the engineering practicality to catalytic vapor upgrading and offers the necessary data for the design and optimization of a full-stream upgrading of pyrolysis oils via in situ vapor cracking. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201831e Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Modeling of chemical vapor deposition of pyrolytic carbon in a gas - spouted bed reactor Type de document : texte imprimé Auteurs : Palash Kumar Mollick, Auteur ; Dakshinamoorthy Sathiyamoorthy, Auteur ; Pandugula Thirmaleshwar Rao, Auteur Année de publication : 2012 Article en page(s) : pp. 13313–13321 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor Fluidization Spouted bed Chemical vapor deposition Modeling Résumé : Spouted beds are used in chemical vapor deposition as they provide good solid mixing, thereby enhancing high mass and heat transfer rates. In the present study, investigations on the kinetics of a coating process by chemical vapor deposition were carried out in a spouted-bed reactor. Pyrolytic carbon coatings were studied by thermal cracking of acetylene mixed with carrier gas argon at 1350 °C. A theoretical model was proposed based on the mass balance of the precursor in the spout and annulus zones at isothermal condition, and the model equations were solved using MATLAB (version 7.1) software. The effect of the operating gas velocity, initial static bed height, and acetylene concentration on the coating rate was examined experimentally and also by simulation results. The simulated results agreed well with the experimental results. Model equations used for simulation were utilized to evaluate the reaction rate constant and radial gas diffusion coefficient and then to study the effect of spout diameter, operating gas velocity, and precursor concentration on the overall conversion of the precursor. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267488
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13313–13321[article] Modeling of chemical vapor deposition of pyrolytic carbon in a gas - spouted bed reactor [texte imprimé] / Palash Kumar Mollick, Auteur ; Dakshinamoorthy Sathiyamoorthy, Auteur ; Pandugula Thirmaleshwar Rao, Auteur . - 2012 . - pp. 13313–13321.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13313–13321
Mots-clés : Reactor Fluidization Spouted bed Chemical vapor deposition Modeling Résumé : Spouted beds are used in chemical vapor deposition as they provide good solid mixing, thereby enhancing high mass and heat transfer rates. In the present study, investigations on the kinetics of a coating process by chemical vapor deposition were carried out in a spouted-bed reactor. Pyrolytic carbon coatings were studied by thermal cracking of acetylene mixed with carrier gas argon at 1350 °C. A theoretical model was proposed based on the mass balance of the precursor in the spout and annulus zones at isothermal condition, and the model equations were solved using MATLAB (version 7.1) software. The effect of the operating gas velocity, initial static bed height, and acetylene concentration on the coating rate was examined experimentally and also by simulation results. The simulated results agreed well with the experimental results. Model equations used for simulation were utilized to evaluate the reaction rate constant and radial gas diffusion coefficient and then to study the effect of spout diameter, operating gas velocity, and precursor concentration on the overall conversion of the precursor. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267488 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Low - temperature catalytic oxidation of monochlorobenzene by ozone over silica - supported manganese oxide Type de document : texte imprimé Auteurs : Hsu Sheng Liang, Auteur ; Hou Chuan Wang, Auteur ; Moo Been Chang, Auteur Année de publication : 2012 Article en page(s) : pp. 13322-13329 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxidation Catalytic reaction Low temperature Résumé : In this study, we investigated the use of a silica-supported manganese oxide prepared through the impregnation method for the low-temperature ( DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267489
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13322-13329[article] Low - temperature catalytic oxidation of monochlorobenzene by ozone over silica - supported manganese oxide [texte imprimé] / Hsu Sheng Liang, Auteur ; Hou Chuan Wang, Auteur ; Moo Been Chang, Auteur . - 2012 . - pp. 13322-13329.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13322-13329
Mots-clés : Oxidation Catalytic reaction Low temperature Résumé : In this study, we investigated the use of a silica-supported manganese oxide prepared through the impregnation method for the low-temperature ( DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267489 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Kinetics of copper oxidation in the air reactor of a chemical looping combustion system using the law of additive reaction times Type de document : texte imprimé Auteurs : Asad H. Sahir, Auteur ; JoAnn S. Lighty, Auteur Année de publication : 2012 Article en page(s) : pp. 13330–13339 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Oxidation Résumé : Chemical looping combustion (CLC) is one of the promising technologies for fuel combustion which has the potential to reduce the energy penalty associated with the CO2 capture process. A CLC system typically consists of two interconnected fluidized beds that act as a fuel and an air reactor, with a recirculating metal/metal-oxide system acting as the carrier of oxygen from the latter to the former. Insights to the design and optimization of an air reactor in a CLC process could be obtained by analyzing the oxidation kinetics by the Law of Additive Reaction Times. The law offers an approximate closed form solution for a gas–solid reaction in which structural changes on reaction can be neglected. It takes into account the pore diffusion of gaseous species in the interior of the porous oxygen carrier. This is in contrast to shrinking-core model, which assumes the occurrence of the reaction along a well-defined sharp reaction interface that progresses into the solid as the reaction occurs; when applied to an initially porous solid, this model is only appropriate when pore diffusion is controlling. This law provides a convenient and realistic means for analyzing the oxidation process in an air reactor of a CLC system. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201577g
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13330–13339[article] Kinetics of copper oxidation in the air reactor of a chemical looping combustion system using the law of additive reaction times [texte imprimé] / Asad H. Sahir, Auteur ; JoAnn S. Lighty, Auteur . - 2012 . - pp. 13330–13339.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13330–13339
Mots-clés : Kinetics Oxidation Résumé : Chemical looping combustion (CLC) is one of the promising technologies for fuel combustion which has the potential to reduce the energy penalty associated with the CO2 capture process. A CLC system typically consists of two interconnected fluidized beds that act as a fuel and an air reactor, with a recirculating metal/metal-oxide system acting as the carrier of oxygen from the latter to the former. Insights to the design and optimization of an air reactor in a CLC process could be obtained by analyzing the oxidation kinetics by the Law of Additive Reaction Times. The law offers an approximate closed form solution for a gas–solid reaction in which structural changes on reaction can be neglected. It takes into account the pore diffusion of gaseous species in the interior of the porous oxygen carrier. This is in contrast to shrinking-core model, which assumes the occurrence of the reaction along a well-defined sharp reaction interface that progresses into the solid as the reaction occurs; when applied to an initially porous solid, this model is only appropriate when pore diffusion is controlling. This law provides a convenient and realistic means for analyzing the oxidation process in an air reactor of a CLC system. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201577g Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Sulfur-Emission-Free Process of Molybdenum Carbide Synthesis by Lime-Enhanced Molybdenum Disulfide Reduction with Methane Type de document : texte imprimé Auteurs : Samad Ghasemi, Auteur ; Mohammad Hasan Abbasi, Auteur ; Ali Saidi, Auteur Année de publication : 2012 Article en page(s) : pp. 13340-13346 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Molybdenum carbide disulfide Résumé : To investigate a sulfur-emission-free process of molybdenum carbide synthesis from molybdenite, the reaction pathways of MoS2 reduction with methane in the presence of lime (CaO) have been studied. A mixture of MoS2 + 2CaO was reduced isothermally with CH4 in a microreactor, and the composition of effluent gases and the reduced fraction were determined as a function of reaction time. Analysis of the solid phase at different reaction times at 800 °C showed the formation of CaMoO4 as an intermediate phase. Hence, the reaction pathways proposed for reduction of MoS2 + CaO with CH4 involves the direct reduction of MoS2 with CH4 to form Mo2C and sulfur-containing gases. The sulfur-containing gases are captured by CaO to form CaS, CO(g), CO2(g), and H2O(g). The uureacted MoS2 is oxidized by CO2(g) and H2O(g) to form MoO3(g), which reacted with CaO to form CaMoO4 on CaO particles. Finally, CaMoO4 and remaining MoS2 are further reduced with CH4, Characterization of solid samples was carried out by XRD, CHN, and FE-SEM equipped with EDS, providing results consistent with the proposed reaction pathways. Carbon content of solid sample increased with reduction time, and in fully reduced sample at 800 °C it was well above the stoichiometric amount indicating considerable excess carbon deposition due to CH4 cracking. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201860h
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13340-13346[article] Sulfur-Emission-Free Process of Molybdenum Carbide Synthesis by Lime-Enhanced Molybdenum Disulfide Reduction with Methane [texte imprimé] / Samad Ghasemi, Auteur ; Mohammad Hasan Abbasi, Auteur ; Ali Saidi, Auteur . - 2012 . - pp. 13340-13346.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13340-13346
Mots-clés : Molybdenum carbide disulfide Résumé : To investigate a sulfur-emission-free process of molybdenum carbide synthesis from molybdenite, the reaction pathways of MoS2 reduction with methane in the presence of lime (CaO) have been studied. A mixture of MoS2 + 2CaO was reduced isothermally with CH4 in a microreactor, and the composition of effluent gases and the reduced fraction were determined as a function of reaction time. Analysis of the solid phase at different reaction times at 800 °C showed the formation of CaMoO4 as an intermediate phase. Hence, the reaction pathways proposed for reduction of MoS2 + CaO with CH4 involves the direct reduction of MoS2 with CH4 to form Mo2C and sulfur-containing gases. The sulfur-containing gases are captured by CaO to form CaS, CO(g), CO2(g), and H2O(g). The uureacted MoS2 is oxidized by CO2(g) and H2O(g) to form MoO3(g), which reacted with CaO to form CaMoO4 on CaO particles. Finally, CaMoO4 and remaining MoS2 are further reduced with CH4, Characterization of solid samples was carried out by XRD, CHN, and FE-SEM equipped with EDS, providing results consistent with the proposed reaction pathways. Carbon content of solid sample increased with reduction time, and in fully reduced sample at 800 °C it was well above the stoichiometric amount indicating considerable excess carbon deposition due to CH4 cracking. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201860h Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : An Efficient Catalyst for the Large Scale Production of Multi-Walled Carbon Nanotubes Type de document : texte imprimé Auteurs : Jayaseelan Logeswari, Auteur ; Arumugam Pandurangan, Auteur ; Dharmalingam Sangeetha, Auteur Année de publication : 2012 Article en page(s) : pp. 13347–13354 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon nanotubes Résumé : The main objective of this work is to design an efficient catalyst for the synthesis of multiwalled carbon nanotubes (MWNTs) in our scalable, high quality with gram amount synthesis. The catalysts with composition of Fe, Mo, and MgO in the molar ratios 1:0.5:13, 1:1:13, and 1:1:50 were prepared by combustion method. The high acetylene conversion and carbon yield of chemical vapor deposition (CVD) reaction suggest the formation of MWNTs by 1:1:50 molar ratio catalysts under pyrolysis of the pure C2H2 gas with the flow rate about 60 mL/min at 800 ̊C for 30 min. The catalysts and the resulting CNT samples were analyzed by XRD, TGA, FT-Raman, SEM, and TEM to establish a relation between catalyst design and MWNT yield. Raman results indicate that CNTs are in multiwalled structure, since no single-walled characteristic features appear in the 200–400 cm–1 region. We give evidence that increased carbon conversion, carbon yields and % purity of more than 65%, 1000%, and 99%, respectively, with respect to our catalysts are directly related to ratio between Fe–Mo and MgO. One g of acetylene containing 0.9231 g of carbon would enter the reaction chamber, which is responsible for the 1.96, 1.9842, and 2.2356 g of the carbon deposition per 200 mg of catalyst A, B, and C respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102525u
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13347–13354[article] An Efficient Catalyst for the Large Scale Production of Multi-Walled Carbon Nanotubes [texte imprimé] / Jayaseelan Logeswari, Auteur ; Arumugam Pandurangan, Auteur ; Dharmalingam Sangeetha, Auteur . - 2012 . - pp. 13347–13354.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13347–13354
Mots-clés : Carbon nanotubes Résumé : The main objective of this work is to design an efficient catalyst for the synthesis of multiwalled carbon nanotubes (MWNTs) in our scalable, high quality with gram amount synthesis. The catalysts with composition of Fe, Mo, and MgO in the molar ratios 1:0.5:13, 1:1:13, and 1:1:50 were prepared by combustion method. The high acetylene conversion and carbon yield of chemical vapor deposition (CVD) reaction suggest the formation of MWNTs by 1:1:50 molar ratio catalysts under pyrolysis of the pure C2H2 gas with the flow rate about 60 mL/min at 800 ̊C for 30 min. The catalysts and the resulting CNT samples were analyzed by XRD, TGA, FT-Raman, SEM, and TEM to establish a relation between catalyst design and MWNT yield. Raman results indicate that CNTs are in multiwalled structure, since no single-walled characteristic features appear in the 200–400 cm–1 region. We give evidence that increased carbon conversion, carbon yields and % purity of more than 65%, 1000%, and 99%, respectively, with respect to our catalysts are directly related to ratio between Fe–Mo and MgO. One g of acetylene containing 0.9231 g of carbon would enter the reaction chamber, which is responsible for the 1.96, 1.9842, and 2.2356 g of the carbon deposition per 200 mg of catalyst A, B, and C respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102525u Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Preparation of Mesoporous ZnO Microspheres through a Membrane-Dispersion Microstructured Reactor and a Hydrothermal Treatment Type de document : texte imprimé Auteurs : Chunling Zhang, Auteur ; Yujun Wang, Auteur ; Siwei Bi, Auteur Année de publication : 2012 Article en page(s) : pp. 13355-13361 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrothermal treatment Reactor Dispersion Microsphere Preparation Résumé : Mesoporous ZnO microspheres with a diameter of about 10 μm were prepared through the combination of a membrane-dispersion microstructured reactor with a hydrothermal process. First, ZnSO4 reacted with NH4HCO3 in a membrane-dispersion reactor to produce the Zn5(CO3)2(OH)6 precursor, and then the precursor was treated at the temperature of 80 °C for 2 h to form the Zn5(CO3)2(OH)6 microspheres aided by the surfactant CTAB or F127; after the calcinations, mesoporous ZnO microspheres were obtained. The experimental results showed that the morphology of ZnO microspheres obtained using the membrane-dispersion microstructured reactor to mix the raw materials was better than that of those obtained using stirred tanks. Without surfactants and the hydrothermal treatment of the precursors, uniform ZnO microspheres could not be obtained. The SEM images showed that the monodispersed ZnO microspheres were assembled by the plates, and deeper observations revealed that these plates were aggregated by the ZnO nanorods formed by ZnO nanoparticles with a diameter of 9.0 nm. The adsorption-desorption isotherm curve indicated that the ZnO microspheres had mesoporous structures with an average pore diameter of 13.8 nm when using CTAB as the surfactant, and the specific surface area of the ZnO microspheres could reach 71.3 m2/g, much higher than that of ZnO nanoparticles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267493
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13355-13361[article] Preparation of Mesoporous ZnO Microspheres through a Membrane-Dispersion Microstructured Reactor and a Hydrothermal Treatment [texte imprimé] / Chunling Zhang, Auteur ; Yujun Wang, Auteur ; Siwei Bi, Auteur . - 2012 . - pp. 13355-13361.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13355-13361
Mots-clés : Hydrothermal treatment Reactor Dispersion Microsphere Preparation Résumé : Mesoporous ZnO microspheres with a diameter of about 10 μm were prepared through the combination of a membrane-dispersion microstructured reactor with a hydrothermal process. First, ZnSO4 reacted with NH4HCO3 in a membrane-dispersion reactor to produce the Zn5(CO3)2(OH)6 precursor, and then the precursor was treated at the temperature of 80 °C for 2 h to form the Zn5(CO3)2(OH)6 microspheres aided by the surfactant CTAB or F127; after the calcinations, mesoporous ZnO microspheres were obtained. The experimental results showed that the morphology of ZnO microspheres obtained using the membrane-dispersion microstructured reactor to mix the raw materials was better than that of those obtained using stirred tanks. Without surfactants and the hydrothermal treatment of the precursors, uniform ZnO microspheres could not be obtained. The SEM images showed that the monodispersed ZnO microspheres were assembled by the plates, and deeper observations revealed that these plates were aggregated by the ZnO nanorods formed by ZnO nanoparticles with a diameter of 9.0 nm. The adsorption-desorption isotherm curve indicated that the ZnO microspheres had mesoporous structures with an average pore diameter of 13.8 nm when using CTAB as the surfactant, and the specific surface area of the ZnO microspheres could reach 71.3 m2/g, much higher than that of ZnO nanoparticles. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267493 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Anodic dissolution of pure aluminum during electrocoagulation process : influence of supporting electrolyte, Initial pH, and current density Type de document : texte imprimé Auteurs : Khaled Mansouri, Auteur ; Karim Ibrik, Auteur ; Nasr Bensalah, Auteur Année de publication : 2012 Article en page(s) : pp. 13362-13372 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Density pH Electrolyte Electrocoagulation Dissolution Résumé : In this work, effects of some experimental parameters (supporting electrolyte, initial pH, and current density) on aluminum corrosion and anodic dissolution of aluminum during electrocoagulation process were investigated. Potentiodynamic polarization tests, impedance spectroscopy measurements and potentisotatic current density transients were used to evaluate corrosion parameters and verify effects of supporting electrolyte and initial pH on aluminum corrosion. The presence of NaCl and Na2SO4 shifted the corrosion potential toward more cathodic potentials, indicating that corrosion of aluminum is catalyzed by the presence NaCl and Na2SO4. On the contrary, the presence of NaH2PO4 increased the corrosion potential, which indicates that the presence of NaH2PO4 inhibits the corrosion of aluminum. Galvanostatic electrolyses demonstrated that measured concentrations of aluminum exceeded theoretical values calculated using Faraday's Law. The excess in dissolved aluminum produced during galvanostatic electrolyses is primary due to the chemical dissolution of aluminum, which is more significant at highly alkaline conditions. A final pH of value around pH 9 was observed in the presence of NaCl for pH values in the range pH 4―11 which can be explained by buffering effects of aluminum hydroxides. DEWEY : 660 ISSN : 088-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267494
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13362-13372[article] Anodic dissolution of pure aluminum during electrocoagulation process : influence of supporting electrolyte, Initial pH, and current density [texte imprimé] / Khaled Mansouri, Auteur ; Karim Ibrik, Auteur ; Nasr Bensalah, Auteur . - 2012 . - pp. 13362-13372.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13362-13372
Mots-clés : Density pH Electrolyte Electrocoagulation Dissolution Résumé : In this work, effects of some experimental parameters (supporting electrolyte, initial pH, and current density) on aluminum corrosion and anodic dissolution of aluminum during electrocoagulation process were investigated. Potentiodynamic polarization tests, impedance spectroscopy measurements and potentisotatic current density transients were used to evaluate corrosion parameters and verify effects of supporting electrolyte and initial pH on aluminum corrosion. The presence of NaCl and Na2SO4 shifted the corrosion potential toward more cathodic potentials, indicating that corrosion of aluminum is catalyzed by the presence NaCl and Na2SO4. On the contrary, the presence of NaH2PO4 increased the corrosion potential, which indicates that the presence of NaH2PO4 inhibits the corrosion of aluminum. Galvanostatic electrolyses demonstrated that measured concentrations of aluminum exceeded theoretical values calculated using Faraday's Law. The excess in dissolved aluminum produced during galvanostatic electrolyses is primary due to the chemical dissolution of aluminum, which is more significant at highly alkaline conditions. A final pH of value around pH 9 was observed in the presence of NaCl for pH values in the range pH 4―11 which can be explained by buffering effects of aluminum hydroxides. DEWEY : 660 ISSN : 088-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267494 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Fast - rate – constant - rate oxidation kinetics model for asphalt binders Type de document : texte imprimé Auteurs : Xin Jin, Auteur ; Rongbin Han, Auteur ; Yuanchen Cui, Auteur Année de publication : 2012 Article en page(s) : pp. 13373-13379 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Binders Kinetic model Oxidation Kinetics Rate constant Résumé : Asphalt oxidative aging at constant temperature is characterized by a declining fast-rate period and a constant-rate period. While constant-rate reaction kinetics are known for many asphalt materials, much less is known about the equally important fast-rate region. Fifteen modified and unmodified asphalts were aged at five temperatures in 1 atm air, with samples collected during both fast-rate and constant-rate periods. Arrhenius kinetics parameters were obtained for both reactions; an additional parameter characterizes the total oxidation that occurs by the fast-rate, first-order reaction. Interestingly, the data show correlations between the kinetics parameters. Viscosity hardening in response to oxidation, as characterized by hardening susceptibility, is not significantly different for the two aging periods for a single binder. Therefore, the combined first-order, zero-order oxidation model together with hardening susceptibility is capable of modeling asphalt oxidation and hardening. Such a capability is fundamentally important to modeling pavement oxidation, to predicting pavement performance, and to improving pavement design. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267495
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13373-13379[article] Fast - rate – constant - rate oxidation kinetics model for asphalt binders [texte imprimé] / Xin Jin, Auteur ; Rongbin Han, Auteur ; Yuanchen Cui, Auteur . - 2012 . - pp. 13373-13379.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13373-13379
Mots-clés : Modeling Binders Kinetic model Oxidation Kinetics Rate constant Résumé : Asphalt oxidative aging at constant temperature is characterized by a declining fast-rate period and a constant-rate period. While constant-rate reaction kinetics are known for many asphalt materials, much less is known about the equally important fast-rate region. Fifteen modified and unmodified asphalts were aged at five temperatures in 1 atm air, with samples collected during both fast-rate and constant-rate periods. Arrhenius kinetics parameters were obtained for both reactions; an additional parameter characterizes the total oxidation that occurs by the fast-rate, first-order reaction. Interestingly, the data show correlations between the kinetics parameters. Viscosity hardening in response to oxidation, as characterized by hardening susceptibility, is not significantly different for the two aging periods for a single binder. Therefore, the combined first-order, zero-order oxidation model together with hardening susceptibility is capable of modeling asphalt oxidation and hardening. Such a capability is fundamentally important to modeling pavement oxidation, to predicting pavement performance, and to improving pavement design. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267495 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : CoAl - CrO4 layered double hydroxides as selective oxidation catalysts at room temperature Type de document : texte imprimé Auteurs : Jinesh Cherukattu Manayil, Auteur ; Sivashunmugam Sankaranarayanan, Auteur ; Deep Singh Bhadoria, Auteur Année de publication : 2012 Article en page(s) : pp.13380–13386 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydroxides Oxidation Catalysts Résumé : A new combined approach of using layered double hydroxides (LDHs) for both environmental remediation and the derived material as heterogeneous catalyst for selective oxidation is presented. A series of CoAl LDHs with carbonate or nitrate anion in the interlayers was synthesized by two different methods, namely, constant-pH precipitation using NaOH as precipitating agent and homogeneous precipitation by hexamine hydrolysis. The samples were optimized for chromate removal and an uptake of 45 mg Cr/g was obtained for CoAl2-N (CoAl-LDH with Co/Al atomic ratio of 2 and nitrate as interlayer anion by constant-pH precipitation) which was significantly higher than its corresponding carbonate sample that showed 15 mg Cr/g. The thus derived materials after uptake of chromate were explored for solvent free selective oxidation of benzyl alcohol using tert-butyl hydroperoxide as oxidant at room temperature. Among the catalysts screened, CoAl2-N sample after chromate uptake gave 23% conversion with 100% selectivity for benzaldehyde using a catalyst/substrate weight ratio 1:20. The catalyst was recyclable up to four cycles, and the reaction was heterogeneous. The studies revealed that the chromate ion-exchanged sample was more stable and selective as oxidation catalyst than that of surface adsorbed sample. The observed activity of this catalyst was ascribed to the cooperative contribution of Co and Cr. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201436b
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp.13380–13386[article] CoAl - CrO4 layered double hydroxides as selective oxidation catalysts at room temperature [texte imprimé] / Jinesh Cherukattu Manayil, Auteur ; Sivashunmugam Sankaranarayanan, Auteur ; Deep Singh Bhadoria, Auteur . - 2012 . - pp.13380–13386.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp.13380–13386
Mots-clés : Hydroxides Oxidation Catalysts Résumé : A new combined approach of using layered double hydroxides (LDHs) for both environmental remediation and the derived material as heterogeneous catalyst for selective oxidation is presented. A series of CoAl LDHs with carbonate or nitrate anion in the interlayers was synthesized by two different methods, namely, constant-pH precipitation using NaOH as precipitating agent and homogeneous precipitation by hexamine hydrolysis. The samples were optimized for chromate removal and an uptake of 45 mg Cr/g was obtained for CoAl2-N (CoAl-LDH with Co/Al atomic ratio of 2 and nitrate as interlayer anion by constant-pH precipitation) which was significantly higher than its corresponding carbonate sample that showed 15 mg Cr/g. The thus derived materials after uptake of chromate were explored for solvent free selective oxidation of benzyl alcohol using tert-butyl hydroperoxide as oxidant at room temperature. Among the catalysts screened, CoAl2-N sample after chromate uptake gave 23% conversion with 100% selectivity for benzaldehyde using a catalyst/substrate weight ratio 1:20. The catalyst was recyclable up to four cycles, and the reaction was heterogeneous. The studies revealed that the chromate ion-exchanged sample was more stable and selective as oxidation catalyst than that of surface adsorbed sample. The observed activity of this catalyst was ascribed to the cooperative contribution of Co and Cr. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201436b Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Supercritical carbon dioxide induced foaming of highly oriented isotactic polypropylene Type de document : texte imprimé Auteurs : Jin-Biao Bao, Auteur ; Tao Liu, Auteur ; Ling Zhao, Auteur Année de publication : 2012 Article en page(s) : pp. 13387–13395 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dioxide Carbon Isotactic Polypropylene Résumé : A highly oriented isotactic polypropylene (iPP) with a shish-kebab crystalline structure is used as a template to achieve nanocellular foams by CO2 foaming in the solid state. The shish-kebab crystalline structure is obtained by tuning injection-molding conditions. Nanocells are generated in amorphous domains confined by shish-kebab crystalline domains which cannot foam. The highly oriented iPP consists of both shish-kebab crystalline structure and spherulites structure and is used to investigate the effect of the crystalline morphology on the cell formation at a given CO2 saturation pressure (15 MPa) and various foaming temperatures (135, 140, 143, and 146 °C). When the foaming temperature is 143 °C, a uniform open nanocellular morphology is obtained. The cell size and cell density both increase with foaming temperature from 135 to 143 °C due to the fact that more crystals are molten, providing more space for cell nucleation and growth. However, when the foaming temperature is increased to 146 °C, the cell size abruptly increases from dozens of nanometers to dozens of micrometers, and the corresponding cell density decreases by several orders of magnitude. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2018228
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13387–13395[article] Supercritical carbon dioxide induced foaming of highly oriented isotactic polypropylene [texte imprimé] / Jin-Biao Bao, Auteur ; Tao Liu, Auteur ; Ling Zhao, Auteur . - 2012 . - pp. 13387–13395.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13387–13395
Mots-clés : Dioxide Carbon Isotactic Polypropylene Résumé : A highly oriented isotactic polypropylene (iPP) with a shish-kebab crystalline structure is used as a template to achieve nanocellular foams by CO2 foaming in the solid state. The shish-kebab crystalline structure is obtained by tuning injection-molding conditions. Nanocells are generated in amorphous domains confined by shish-kebab crystalline domains which cannot foam. The highly oriented iPP consists of both shish-kebab crystalline structure and spherulites structure and is used to investigate the effect of the crystalline morphology on the cell formation at a given CO2 saturation pressure (15 MPa) and various foaming temperatures (135, 140, 143, and 146 °C). When the foaming temperature is 143 °C, a uniform open nanocellular morphology is obtained. The cell size and cell density both increase with foaming temperature from 135 to 143 °C due to the fact that more crystals are molten, providing more space for cell nucleation and growth. However, when the foaming temperature is increased to 146 °C, the cell size abruptly increases from dozens of nanometers to dozens of micrometers, and the corresponding cell density decreases by several orders of magnitude. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2018228 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Characterization of jack pine early - and iatewood fibers in thermomechanical pulping Type de document : texte imprimé Auteurs : Fang Huang, Auteur ; Robert Lanouette, Auteur ; Kwei-Nam Law, Auteur Année de publication : 2012 Article en page(s) : pp. 13396–13402 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermomechanical Résumé : The principal objective of this research was to study the morphological changes of Jack pine (Pinus banksiana) earlywood (EW) and latewood (LW) in thermomechanical pulping (TMP). The results indicate that EW fibers tend to separate at the P/S1 interface, whereas LW fibers commonly fail in the regions between the primary wall and the transition layer or outer layer of the secondary wall (P/S1) and between the outer and central layers of the secondary wall (S1/S2). LW fibers exhibit mostly intrawall failure and lower curl and kink indices, whereas EW fibers tend to fail in transwall mode (splitting) and suffer fiber cuttings. In addition, the thin-walled EW fibers show higher collapsibility and conformability than their thick-walled LW counterparts. Moreover, EW fines have higher surface lignin coverage, whereas LW fines have a higher specific volume (SV). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2019992
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13396–13402[article] Characterization of jack pine early - and iatewood fibers in thermomechanical pulping [texte imprimé] / Fang Huang, Auteur ; Robert Lanouette, Auteur ; Kwei-Nam Law, Auteur . - 2012 . - pp. 13396–13402.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13396–13402
Mots-clés : Thermomechanical Résumé : The principal objective of this research was to study the morphological changes of Jack pine (Pinus banksiana) earlywood (EW) and latewood (LW) in thermomechanical pulping (TMP). The results indicate that EW fibers tend to separate at the P/S1 interface, whereas LW fibers commonly fail in the regions between the primary wall and the transition layer or outer layer of the secondary wall (P/S1) and between the outer and central layers of the secondary wall (S1/S2). LW fibers exhibit mostly intrawall failure and lower curl and kink indices, whereas EW fibers tend to fail in transwall mode (splitting) and suffer fiber cuttings. In addition, the thin-walled EW fibers show higher collapsibility and conformability than their thick-walled LW counterparts. Moreover, EW fines have higher surface lignin coverage, whereas LW fines have a higher specific volume (SV). DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2019992 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Improvements in petroleum refinery planning : 1. formulation of process models Type de document : texte imprimé Auteurs : Omar J. Guerra, Auteur ; Galo A. C. Le Roux, Auteur Année de publication : 2012 Article en page(s) : pp.13403–13418 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Petroleum Refinery Process models Résumé : Optimization of the production planning is crucial for the economic success of a petroleum refinery. Nevertheless, it is a difficult task, because of the large scale of the system and the complexity of the processes involved. Part 1 of this series of two papers addresses the formulation of process models for petroleum refinery planning. First, a generic formulation of nonlinear refinery planning model is adopted from the literature. Subsequently, the formulation of nonlinear empirical models for crude distillation units (CDUs) and a fluid catalytic cracking (FCC) unit is addressed. These empirical models were successfully validated using rigorous process simulators. Finally, the results from model validation showed that the accuracy of model predictions is as good as the current empirical process models reported in the literature, while the empirical process models proposed in this work overcome the limitations of both linear and nonlinear empirical models for CDUs and FCC units previously developed by other authors. Part 2 [Ind. Eng. Chem. Res.2011, DOI: 10.1021/ie200304v] involves the implementation of nonlinear empirical process models in the petroleum refinery planning. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200303m
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp.13403–13418[article] Improvements in petroleum refinery planning : 1. formulation of process models [texte imprimé] / Omar J. Guerra, Auteur ; Galo A. C. Le Roux, Auteur . - 2012 . - pp.13403–13418.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp.13403–13418
Mots-clés : Petroleum Refinery Process models Résumé : Optimization of the production planning is crucial for the economic success of a petroleum refinery. Nevertheless, it is a difficult task, because of the large scale of the system and the complexity of the processes involved. Part 1 of this series of two papers addresses the formulation of process models for petroleum refinery planning. First, a generic formulation of nonlinear refinery planning model is adopted from the literature. Subsequently, the formulation of nonlinear empirical models for crude distillation units (CDUs) and a fluid catalytic cracking (FCC) unit is addressed. These empirical models were successfully validated using rigorous process simulators. Finally, the results from model validation showed that the accuracy of model predictions is as good as the current empirical process models reported in the literature, while the empirical process models proposed in this work overcome the limitations of both linear and nonlinear empirical models for CDUs and FCC units previously developed by other authors. Part 2 [Ind. Eng. Chem. Res.2011, DOI: 10.1021/ie200304v] involves the implementation of nonlinear empirical process models in the petroleum refinery planning. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200303m Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Improvements in petroleum refinery planning : 2. case studies Type de document : texte imprimé Auteurs : Omar J. Guerra, Auteur ; Galo A. C. Le Roux, Auteur Année de publication : 2012 Article en page(s) : pp. 13419-13426 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Planning Refinery Petroleum Résumé : This paper is the second part of a series of two papers on the recent advances in petroleum refinery planning. In Part 1 (Guerra and Le Roux, Ind. Eng. Chem. Res. 2011, DOI: 10.1021/ie200303m), nonlinear empirical process models for CDUs and a FCC unit were developed. The implementation of these models in two case studies for petroleum refinery planning is presented in this paper. In the first case, the empirical model for CDUs was implemented in the planning model for a small-scale refinery. In the second case, the empirical models for CDUs and a FCC unit were integrated in the planning model for a medium-scale refinery. In both case studies, empirical process models from the literature were adopted for refinery processes that were not considered in Part 1 of this work. In addition, a comparison of the computational performance for three popular nonlinear programming (NLP) solvers is presented in case study 1. The case studies showed that the empirical models developed in Part 1 of this work are computationally adequate for the petroleum refinery planning. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267500
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13419-13426[article] Improvements in petroleum refinery planning : 2. case studies [texte imprimé] / Omar J. Guerra, Auteur ; Galo A. C. Le Roux, Auteur . - 2012 . - pp. 13419-13426.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13419-13426
Mots-clés : Planning Refinery Petroleum Résumé : This paper is the second part of a series of two papers on the recent advances in petroleum refinery planning. In Part 1 (Guerra and Le Roux, Ind. Eng. Chem. Res. 2011, DOI: 10.1021/ie200303m), nonlinear empirical process models for CDUs and a FCC unit were developed. The implementation of these models in two case studies for petroleum refinery planning is presented in this paper. In the first case, the empirical model for CDUs was implemented in the planning model for a small-scale refinery. In the second case, the empirical models for CDUs and a FCC unit were integrated in the planning model for a medium-scale refinery. In both case studies, empirical process models from the literature were adopted for refinery processes that were not considered in Part 1 of this work. In addition, a comparison of the computational performance for three popular nonlinear programming (NLP) solvers is presented in case study 1. The case studies showed that the empirical models developed in Part 1 of this work are computationally adequate for the petroleum refinery planning. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267500 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Optimal structure of learning - type set - point in various set - point - related indirect ILC algorithms Type de document : texte imprimé Auteurs : Youqing Wang, Auteur ; Jianyong Tuo, Auteur ; Zhong Zhao, Auteur Année de publication : 2012 Article en page(s) : pp. 13427–13434 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimal Résumé : According to the literature statistics, only less than 10% of reported iterative learning control (ILC) methods have been devoted to the indirect approach. Motivated by the full potential of research opportunities in this field, a number of studies on indirect ILC were proposed recently, where ILC-based P-type control and learning-type model predictive control (L-MPC) are two successful stories. All indirect ILC algorithms consist of two loops: an ILC in the outer loop and a local controller in the inner loop. The local controllers are, respectively, a P-type controller in the ILC-based P-type control and a model predictive control (MPC) in the L-MPC. Logically, this leads to the question of what type of ILC should be chosen respectively for the two above-mentioned indirect ILC methods. In this study, P-type ILC and anticipatory P-type (A-P-type) ILC are studied and compared, because they are typical and widely implemented. Based on mathematical analysis and simulation test, it has been proved that the A-P-type ILC should be used in the ILC-based P-type control and while the P-type ILC should be used in the L-MPC. Furthermore, an improved L-MPC with batch-varying learning gain was proposed to handle the trade-off between convergence rate and robustness performance. The simulation results on injection molding process and a nonlinear batch process validated the feasibility and effectiveness of the proposed algorithm. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200021t
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13427–13434[article] Optimal structure of learning - type set - point in various set - point - related indirect ILC algorithms [texte imprimé] / Youqing Wang, Auteur ; Jianyong Tuo, Auteur ; Zhong Zhao, Auteur . - 2012 . - pp. 13427–13434.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13427–13434
Mots-clés : Optimal Résumé : According to the literature statistics, only less than 10% of reported iterative learning control (ILC) methods have been devoted to the indirect approach. Motivated by the full potential of research opportunities in this field, a number of studies on indirect ILC were proposed recently, where ILC-based P-type control and learning-type model predictive control (L-MPC) are two successful stories. All indirect ILC algorithms consist of two loops: an ILC in the outer loop and a local controller in the inner loop. The local controllers are, respectively, a P-type controller in the ILC-based P-type control and a model predictive control (MPC) in the L-MPC. Logically, this leads to the question of what type of ILC should be chosen respectively for the two above-mentioned indirect ILC methods. In this study, P-type ILC and anticipatory P-type (A-P-type) ILC are studied and compared, because they are typical and widely implemented. Based on mathematical analysis and simulation test, it has been proved that the A-P-type ILC should be used in the ILC-based P-type control and while the P-type ILC should be used in the L-MPC. Furthermore, an improved L-MPC with batch-varying learning gain was proposed to handle the trade-off between convergence rate and robustness performance. The simulation results on injection molding process and a nonlinear batch process validated the feasibility and effectiveness of the proposed algorithm. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200021t Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Two - stage stochastic programming model for planning CO2 utilization and disposal infrastructure considering the uncertainty in the CO2 emission Type de document : texte imprimé Auteurs : Jee-Hoon Han, Auteur ; In-Beum Lee, Auteur Année de publication : 2012 Article en page(s) : pp. 13435-13443 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mathematical programming Uncertainty Carbon dioxide Planning Modeling Stochastic Résumé : Numerous research works have been undertaken to plan carbon capture and storage (CCS) infrastructures for CO2 utilization and disposal. CO2 emissions are difficult to estimate precisely, because CO2 is emitted from various sources at varying rates. In this study, a two-stage stochastic programming model is developed for planning CCS infrastructure including CO2 utilization and disposal under stochastic CO2 emissions. The proposed model considers uncertainties in the variation of CO2 emissions. It can help determine where and how much CO2 to capture, store, transport, utilize, or sequester for the purpose of maximizing the total profit of handling uncertain CO2 emissions while meeting the CO2 mitigation target. The capability of the proposed model to provide correct decisions despite changing CO2 emissions is tested by applying it to an industrial complex on the eastern coast of Korea in 2020. The results will help to determine planning of, and budgeting for, development of a CCS infrastructure. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267502
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13435-13443[article] Two - stage stochastic programming model for planning CO2 utilization and disposal infrastructure considering the uncertainty in the CO2 emission [texte imprimé] / Jee-Hoon Han, Auteur ; In-Beum Lee, Auteur . - 2012 . - pp. 13435-13443.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13435-13443
Mots-clés : Mathematical programming Uncertainty Carbon dioxide Planning Modeling Stochastic Résumé : Numerous research works have been undertaken to plan carbon capture and storage (CCS) infrastructures for CO2 utilization and disposal. CO2 emissions are difficult to estimate precisely, because CO2 is emitted from various sources at varying rates. In this study, a two-stage stochastic programming model is developed for planning CCS infrastructure including CO2 utilization and disposal under stochastic CO2 emissions. The proposed model considers uncertainties in the variation of CO2 emissions. It can help determine where and how much CO2 to capture, store, transport, utilize, or sequester for the purpose of maximizing the total profit of handling uncertain CO2 emissions while meeting the CO2 mitigation target. The capability of the proposed model to provide correct decisions despite changing CO2 emissions is tested by applying it to an industrial complex on the eastern coast of Korea in 2020. The results will help to determine planning of, and budgeting for, development of a CCS infrastructure. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267502 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : A superstructure optimization approach for membrane separation - based water regeneration network synthesis with detailed nonlinear mechanistic reverse osmosis model Type de document : texte imprimé Auteurs : Cheng Seong Khor, Auteur ; Dominic C. Y. Foo, Auteur ; Mahmoud M. El-Halwagi, Auteur Année de publication : 2012 Article en page(s) : pp. 13444-13456 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Reverse osmosis Membrane separation Optimization Superstructure Résumé : Scarcity of freshwater resources and increasingly stringent environmental regulations on industrial effluents have motivated the process industry to identify and develop various water recovery strategies. This work proposes the use of detailed model representation for water regeneration network synthesis, in which nonlinear mechanistic models of the regeneration units are embedded within an overall mixed-integer nonlinear programming (MINLP) optimization framework. The superstructure-based MINLP framework involves both continuous variables for water flow rates and contaminant concentrations and 0―1 variables for selection ofpiping interconnections. The nonlinear regeneration model produces a rigorous cost-based relation, instead of a "black box" model, that is incorporated within the overall MINLP representing a network of numerous water sources and water sinks. Hence, such an approach enables a simultaneous evaluation of both direct water reuse/recycle and regeneration-reuse/recycle opportunities. To demonstrate the proposed approach, an industrial case study is illustrated that incorporates a mechanistic model of reverse osmosis network (RON) for water regeneration for an operating refinery in Malaysia. The results indicate a potential of 58% savings in freshwater use. The capital investment for the water regeneration network is reported as $8,960,000 with a payback period of 2.1 years, thus providing economic support to pursue the RON retrofit option. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267503
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13444-13456[article] A superstructure optimization approach for membrane separation - based water regeneration network synthesis with detailed nonlinear mechanistic reverse osmosis model [texte imprimé] / Cheng Seong Khor, Auteur ; Dominic C. Y. Foo, Auteur ; Mahmoud M. El-Halwagi, Auteur . - 2012 . - pp. 13444-13456.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13444-13456
Mots-clés : Modeling Reverse osmosis Membrane separation Optimization Superstructure Résumé : Scarcity of freshwater resources and increasingly stringent environmental regulations on industrial effluents have motivated the process industry to identify and develop various water recovery strategies. This work proposes the use of detailed model representation for water regeneration network synthesis, in which nonlinear mechanistic models of the regeneration units are embedded within an overall mixed-integer nonlinear programming (MINLP) optimization framework. The superstructure-based MINLP framework involves both continuous variables for water flow rates and contaminant concentrations and 0―1 variables for selection ofpiping interconnections. The nonlinear regeneration model produces a rigorous cost-based relation, instead of a "black box" model, that is incorporated within the overall MINLP representing a network of numerous water sources and water sinks. Hence, such an approach enables a simultaneous evaluation of both direct water reuse/recycle and regeneration-reuse/recycle opportunities. To demonstrate the proposed approach, an industrial case study is illustrated that incorporates a mechanistic model of reverse osmosis network (RON) for water regeneration for an operating refinery in Malaysia. The results indicate a potential of 58% savings in freshwater use. The capital investment for the water regeneration network is reported as $8,960,000 with a payback period of 2.1 years, thus providing economic support to pursue the RON retrofit option. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267503 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Subspace - modeling - based nonlinear measurement for process design Type de document : texte imprimé Auteurs : XinJiang Lu, Auteur ; MingHui Huang, Auteur ; YiBo Li, Auteur Année de publication : 2012 Article en page(s) : pp. 13457–13465 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nonlinear processes Résumé : In industry, many nonlinear processes can be approximated well by a linear model under a suitable design parameter, upon which a linear controller can effectively control these processes. The key problem is how to find this suitable design parameter, which is never considered in process design. In this paper, a novel design for control approach is proposed to design the process to have a satisfactory linear approximation. First, a subspace-modeling-based nonlinear measurement is proposed to avoid the infinite dimensional optimization problem in the traditional nonlinearity measurement. Then a particle-swarm-optimization-based design approach is developed to obtain the optimal design parameter through solving the nonconvex and nondifferential measurement problem. Finally, the proposed design is applied to design a practical curing oven and compared with the existing design. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2008554
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13457–13465[article] Subspace - modeling - based nonlinear measurement for process design [texte imprimé] / XinJiang Lu, Auteur ; MingHui Huang, Auteur ; YiBo Li, Auteur . - 2012 . - pp. 13457–13465.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13457–13465
Mots-clés : Nonlinear processes Résumé : In industry, many nonlinear processes can be approximated well by a linear model under a suitable design parameter, upon which a linear controller can effectively control these processes. The key problem is how to find this suitable design parameter, which is never considered in process design. In this paper, a novel design for control approach is proposed to design the process to have a satisfactory linear approximation. First, a subspace-modeling-based nonlinear measurement is proposed to avoid the infinite dimensional optimization problem in the traditional nonlinearity measurement. Then a particle-swarm-optimization-based design approach is developed to obtain the optimal design parameter through solving the nonconvex and nondifferential measurement problem. Finally, the proposed design is applied to design a practical curing oven and compared with the existing design. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2008554 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Evaluation tool for the environmental design of chemical processes Type de document : texte imprimé Auteurs : Carmen M. Torres, Auteur ; Mamdouh A. Gadalla, Auteur ; Josep M. Mateo-Sanz, Auteur Année de publication : 2012 Article en page(s) : pp. 13466-13474 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Design Résumé : Since the environmental awareness increases and regulations become more restrictive, chemical industries are forced to adopt measures for minimizing the environmental impact and to include these techniques in the process design. This work proposes a methodology where environment and human health considerations are coupled with the process design of new and existing plants. With this aim, a new assessment tool for the environmental evaluation of chemical processes is presented. It includes the development of a new environmental indicator (Material Balance Environmental Index, MBEl) based on the toxicities of the chemicals involved and the materials flows between the process and environment. Moreover, a total index is computed following three levels of aggregation using the geometric mean of the ratios of several environmental impact categories. The environmental evaluation tool is tested using two case studies (formaldehyde and styrene production), where data are obtained from rigorous process simulation validated with industrial data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267505
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13466-13474[article] Evaluation tool for the environmental design of chemical processes [texte imprimé] / Carmen M. Torres, Auteur ; Mamdouh A. Gadalla, Auteur ; Josep M. Mateo-Sanz, Auteur . - 2012 . - pp. 13466-13474.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13466-13474
Mots-clés : Design Résumé : Since the environmental awareness increases and regulations become more restrictive, chemical industries are forced to adopt measures for minimizing the environmental impact and to include these techniques in the process design. This work proposes a methodology where environment and human health considerations are coupled with the process design of new and existing plants. With this aim, a new assessment tool for the environmental evaluation of chemical processes is presented. It includes the development of a new environmental indicator (Material Balance Environmental Index, MBEl) based on the toxicities of the chemicals involved and the materials flows between the process and environment. Moreover, a total index is computed following three levels of aggregation using the geometric mean of the ratios of several environmental impact categories. The environmental evaluation tool is tested using two case studies (formaldehyde and styrene production), where data are obtained from rigorous process simulation validated with industrial data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267505 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Production of B - carotene nanoparticles by the solution enhanced dispersion with enhanced mass transfer by ultrasound in supercritical CO2 (SEDS - EM) Type de document : texte imprimé Auteurs : He Yang Jin, Auteur ; Melinda Hemingway, Auteur ; Fei Xia, Auteur Année de publication : 2012 Article en page(s) : pp. 13475–13484 Note générale : Chimie industrielle Langues : Anglais (eng) Résumé : In recent years, the solution enhanced dispersion in supercritical fluids (SEDS) technique is widely applied to produce fine and small particles of drugs and other active ingredients. However, this technique still cannot be used to generate particles in the submicrometer range for specific compounds, such as carotenoids. In this study, a modified SEDS technique is explored and applied in the preparation of β-carotene nanoparticles with relatively narrow size distribution. This novel technique, termed SEDS-EM, combines a traditional SEDS technique with ultrasonication from the supercritical antisolvent with enhanced mass transfer precipitation technique (SAS-EM). For this new technique, the β-carotene solution is premixed with the antisolvent (supercritical CO2) in a coaxial nozzle; then the mixed solution is sprayed from the coaxial nozzle onto a surface vibrating at an ultrasonic frequency. The solution jet is dispersed by the coaxial nozzle and further atomized into very small droplets by the ultrasonic vibrating surface. This combination of a coaxial nozzle and the ultrasound field enhances the mass transfer between the solution and the antisolvent. The resultant β-carotene particles decreased in size from the micrometer range (2–5 μm) by SEDS to the nanometer range (20–205 nm) by SEDS-EM. This smaller particle size can be controlled by the power supplied from the attached ultrasound transducer utilized in SEDS-EM. The size and morphology of the particles are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effects of the process parameters on the β-carotene yield are discussed. The crystallography transformation of the processed and unprocessed β-carotene is characterized by XRD and FTIR. The particle precipitation in sub and near critical regions of the DCM-CO2 binary system is also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2011565
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13475–13484[article] Production of B - carotene nanoparticles by the solution enhanced dispersion with enhanced mass transfer by ultrasound in supercritical CO2 (SEDS - EM) [texte imprimé] / He Yang Jin, Auteur ; Melinda Hemingway, Auteur ; Fei Xia, Auteur . - 2012 . - pp. 13475–13484.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13475–13484
Résumé : In recent years, the solution enhanced dispersion in supercritical fluids (SEDS) technique is widely applied to produce fine and small particles of drugs and other active ingredients. However, this technique still cannot be used to generate particles in the submicrometer range for specific compounds, such as carotenoids. In this study, a modified SEDS technique is explored and applied in the preparation of β-carotene nanoparticles with relatively narrow size distribution. This novel technique, termed SEDS-EM, combines a traditional SEDS technique with ultrasonication from the supercritical antisolvent with enhanced mass transfer precipitation technique (SAS-EM). For this new technique, the β-carotene solution is premixed with the antisolvent (supercritical CO2) in a coaxial nozzle; then the mixed solution is sprayed from the coaxial nozzle onto a surface vibrating at an ultrasonic frequency. The solution jet is dispersed by the coaxial nozzle and further atomized into very small droplets by the ultrasonic vibrating surface. This combination of a coaxial nozzle and the ultrasound field enhances the mass transfer between the solution and the antisolvent. The resultant β-carotene particles decreased in size from the micrometer range (2–5 μm) by SEDS to the nanometer range (20–205 nm) by SEDS-EM. This smaller particle size can be controlled by the power supplied from the attached ultrasound transducer utilized in SEDS-EM. The size and morphology of the particles are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effects of the process parameters on the β-carotene yield are discussed. The crystallography transformation of the processed and unprocessed β-carotene is characterized by XRD and FTIR. The particle precipitation in sub and near critical regions of the DCM-CO2 binary system is also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2011565 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Process optimization of FT - diesel production from lignocellulosic switchgrass Type de document : texte imprimé Auteurs : Mariano Martin, Auteur ; Ignacio E. Grossmann, Auteur Année de publication : 2012 Article en page(s) : pp. 13485–13499 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization Lignocellulosic Résumé : In this paper, we present the conceptual design for the optimization of FT-diesel production process from switchgrass via gasification of biomass. We propose a limited superstructure where the process starts with the gasification of the biomass. Two different alternatives are evaluated, direct and indirect gasification. The gas obtained is cleaned up and its composition adjusted in terms of the ratio CO/H2 considering a bypass, a PSA system and water gas shift reaction. Next, the removal of CO2 and H2S is performed using absorption in monoethanolamines and PSA. Once the syngas is prepared, the Fischer-Tropsch reaction is conducted and the products separated. Hydrocracking of the heavy products is also considered to increase the yield toward green diesel. The optimization of the system is formulated as an equation-based Mixed-Integer Nonlinear Programming (MINLP) problem that is solved for the optimal production of the biodiesel fraction while minimizing the energy consumption and the hydrogen consumption. The optimal solution requires the use of indirect gasification followed by steam reforming. The ratio of CO/H2 is left unchanged as the one obtained after gas reforming, while adjusting the temperature at the FT reactor and the operating conditions of the hydrocracking to increase the FT-diesel production. A promising production cost of 0.71 $/gallon is obtained, and only 0.15 gal Water/gal bioifuel of water consumption is required if air cooling is implemented in the plant. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201261t
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13485–13499[article] Process optimization of FT - diesel production from lignocellulosic switchgrass [texte imprimé] / Mariano Martin, Auteur ; Ignacio E. Grossmann, Auteur . - 2012 . - pp. 13485–13499.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13485–13499
Mots-clés : Optimization Lignocellulosic Résumé : In this paper, we present the conceptual design for the optimization of FT-diesel production process from switchgrass via gasification of biomass. We propose a limited superstructure where the process starts with the gasification of the biomass. Two different alternatives are evaluated, direct and indirect gasification. The gas obtained is cleaned up and its composition adjusted in terms of the ratio CO/H2 considering a bypass, a PSA system and water gas shift reaction. Next, the removal of CO2 and H2S is performed using absorption in monoethanolamines and PSA. Once the syngas is prepared, the Fischer-Tropsch reaction is conducted and the products separated. Hydrocracking of the heavy products is also considered to increase the yield toward green diesel. The optimization of the system is formulated as an equation-based Mixed-Integer Nonlinear Programming (MINLP) problem that is solved for the optimal production of the biodiesel fraction while minimizing the energy consumption and the hydrogen consumption. The optimal solution requires the use of indirect gasification followed by steam reforming. The ratio of CO/H2 is left unchanged as the one obtained after gas reforming, while adjusting the temperature at the FT reactor and the operating conditions of the hydrocracking to increase the FT-diesel production. A promising production cost of 0.71 $/gallon is obtained, and only 0.15 gal Water/gal bioifuel of water consumption is required if air cooling is implemented in the plant. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201261t Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : A GA - based neural fuzzy system for modeling a paper mill wastewater treatment process Type de document : texte imprimé Auteurs : Mingzhi Huang, Auteur ; Jinquan Wan, Auteur ; Yongwen Ma, Auteur Année de publication : 2012 Article en page(s) : pp. 13500–13507 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Neural fuzzy system Wastewater treatment Résumé : A genetic algorithm-based neural fuzzy system (GA-NFS) was presented for studying the coagulation process of wastewater treatment in a paper mill. In order to adapt the system to a variety of operating conditions and acquire a more flexible learning ability, the GA-NFS was employed to model the nonlinear relationships between the effluent concentration of pollutants and the chemical dosages, and a hybrid learning algorithm divided into two stages was proposed for parameters learning. During the first learning stage, a genetic algorithm was used to optimize the structure of GA-NFS and the membership function of each fuzzy term due to its capability of parallel and global search. On the basis of an optimized training stage, the back-propagation algorithm (BP algorithm) was chosen to update the parameters of GA-NFS to improve the system precision. The GA-NFS proves to be very effective in modeling coagulation perform and performs better than adaptive-network-based fuzzy inference system (ANFIS). RMSE, MAPE, and R between the predicted and observed values for GA-NFS were only 0.01099, 2.3337, and 0.9375, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201296p
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13500–13507[article] A GA - based neural fuzzy system for modeling a paper mill wastewater treatment process [texte imprimé] / Mingzhi Huang, Auteur ; Jinquan Wan, Auteur ; Yongwen Ma, Auteur . - 2012 . - pp. 13500–13507.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13500–13507
Mots-clés : Neural fuzzy system Wastewater treatment Résumé : A genetic algorithm-based neural fuzzy system (GA-NFS) was presented for studying the coagulation process of wastewater treatment in a paper mill. In order to adapt the system to a variety of operating conditions and acquire a more flexible learning ability, the GA-NFS was employed to model the nonlinear relationships between the effluent concentration of pollutants and the chemical dosages, and a hybrid learning algorithm divided into two stages was proposed for parameters learning. During the first learning stage, a genetic algorithm was used to optimize the structure of GA-NFS and the membership function of each fuzzy term due to its capability of parallel and global search. On the basis of an optimized training stage, the back-propagation algorithm (BP algorithm) was chosen to update the parameters of GA-NFS to improve the system precision. The GA-NFS proves to be very effective in modeling coagulation perform and performs better than adaptive-network-based fuzzy inference system (ANFIS). RMSE, MAPE, and R between the predicted and observed values for GA-NFS were only 0.01099, 2.3337, and 0.9375, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201296p Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : CO2 - Tolerant oxygen - permeable Fe2O3 - Ce0.9Gd0.1O2 - δ dual phase membranes Type de document : texte imprimé Auteurs : Huixia Luo, Auteur ; Heqing Jiang, Auteur ; Konstantin Efimov, Auteur Année de publication : 2012 Article en page(s) : pp. 13508–13517 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Phase membranes Oxygen permeable Résumé : CO2-stable oxygen-permeable Fe2O3 (FO) - Ce0.9Gd0.1O2-δ (CGO) dual phase composite membranes of the composition χ wt % FO - (100 – χ) wt % CGO with χ = 25, 40, 50 were successfully prepared via a one-pot single-step method. X-ray diffraction (XRD) demonstrated that all FO - CGO composite membranes after sintering at 1300 °C for 5 h represent a microscale mixture of only the two pure phases FO and CGO. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS), and oxygen permeation revealed that the microstructure of the composition of the χ FO - (100 – χ) CGO dual phase membranes has a great influence on the oxygen permeability including its time-dependence. It was found that the composition of 40FO - 60CGO displays the highest oxygen permeability. An oxygen permeation flux of 0.18 mL/min·cm2 was obtained through the uncoated 40FO - 60CGO membrane with a thickness of 0.5 mm under an air/He oxygen gradient at 1000 °C. In situ XRD demonstrates that the 40FO - 60CGO material possesses a good phase stability not only in an atmosphere of 50 vol % CO2/50 vol % Ar but also in other atmospheres with a low oxygen partial pressure like reduced pressure (vacuum) and 5 vol % H2/95 vol % He. After coating the 40FO - 60CGO dual phase membrane with a porous La0.6Sr0.4CoO3-δ (LSC) layer of a few μm thicknesses on the air side, the oxygen permeation flux reaches the steady state immediately. This steady oxygen permeation flux of the LSC coated membrane was found to be 0.20 mL/min·cm2 unchanged for more than 150 h even when pure CO2 was used as the sweep gas, which indicates that the coated 40FO - 60CGO dual phase membrane is CO2 stable. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200517t
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13508–13517[article] CO2 - Tolerant oxygen - permeable Fe2O3 - Ce0.9Gd0.1O2 - δ dual phase membranes [texte imprimé] / Huixia Luo, Auteur ; Heqing Jiang, Auteur ; Konstantin Efimov, Auteur . - 2012 . - pp. 13508–13517.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13508–13517
Mots-clés : Phase membranes Oxygen permeable Résumé : CO2-stable oxygen-permeable Fe2O3 (FO) - Ce0.9Gd0.1O2-δ (CGO) dual phase composite membranes of the composition χ wt % FO - (100 – χ) wt % CGO with χ = 25, 40, 50 were successfully prepared via a one-pot single-step method. X-ray diffraction (XRD) demonstrated that all FO - CGO composite membranes after sintering at 1300 °C for 5 h represent a microscale mixture of only the two pure phases FO and CGO. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS), and oxygen permeation revealed that the microstructure of the composition of the χ FO - (100 – χ) CGO dual phase membranes has a great influence on the oxygen permeability including its time-dependence. It was found that the composition of 40FO - 60CGO displays the highest oxygen permeability. An oxygen permeation flux of 0.18 mL/min·cm2 was obtained through the uncoated 40FO - 60CGO membrane with a thickness of 0.5 mm under an air/He oxygen gradient at 1000 °C. In situ XRD demonstrates that the 40FO - 60CGO material possesses a good phase stability not only in an atmosphere of 50 vol % CO2/50 vol % Ar but also in other atmospheres with a low oxygen partial pressure like reduced pressure (vacuum) and 5 vol % H2/95 vol % He. After coating the 40FO - 60CGO dual phase membrane with a porous La0.6Sr0.4CoO3-δ (LSC) layer of a few μm thicknesses on the air side, the oxygen permeation flux reaches the steady state immediately. This steady oxygen permeation flux of the LSC coated membrane was found to be 0.20 mL/min·cm2 unchanged for more than 150 h even when pure CO2 was used as the sweep gas, which indicates that the coated 40FO - 60CGO dual phase membrane is CO2 stable. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200517t Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Equilibrium and kinetic studies on reactive extraction of pyruvic acid with trioctylamine in 1 - octanol Type de document : texte imprimé Auteurs : Mustafa E. Marti, Auteur ; Turker Gurkan, Auteur ; L. K. Doraiswamy, Auteur Année de publication : 2012 Article en page(s) : pp. 13518–13525 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetic Résumé : Interest in pyruvic acid has been growing due to the increase in its potential areas of use and its importance in metabolic reactions. These reasons along with the limitations on recovery have prompted researchers to consider novel recovery techniques. Reactive extraction has been proposed as a promising approach to the recovery of carboxylic acids. In this study, equilibrium and kinetic data were obtained for reactive extraction of pyruvic acid using trioctylamine (TOA) or Alamine 336 in 1-octanol or oleyl alcohol. The results showed that, without pH adjustment in the aqueous phase, and without the use of an extractant, 1-octanol extracted more pyruvic acid than oleyl alcohol with a distribution coefficient (KD) of 0.30. This trend remained the same when tertiary amines were used as an extractant. The KD values did not significantly differ with TOA or Alamine 336. The recovery of pyruvic acid was observed to increase as a function of TOA concentration and the stoichiometry of the reaction was mainly 1:1. As tertiary amines react only with undissociated acids, an increase in the initial pH of the aqueous phase lowered the KD values. When the pH was 4.0, the effect of TOA concentration on pyruvic acid extraction disappeared and for all concentration levels a distribution coefficient of 0.10 was obtained. Kinetic measurements showed that the reaction between pyruvic acid and TOA in 1-octanol is first order with respect to the two reactants with a rate constant of 0.94 L mol–1 s–1. The enhancement factor was calculated as 25. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200625q
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13518–13525[article] Equilibrium and kinetic studies on reactive extraction of pyruvic acid with trioctylamine in 1 - octanol [texte imprimé] / Mustafa E. Marti, Auteur ; Turker Gurkan, Auteur ; L. K. Doraiswamy, Auteur . - 2012 . - pp. 13518–13525.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13518–13525
Mots-clés : Kinetic Résumé : Interest in pyruvic acid has been growing due to the increase in its potential areas of use and its importance in metabolic reactions. These reasons along with the limitations on recovery have prompted researchers to consider novel recovery techniques. Reactive extraction has been proposed as a promising approach to the recovery of carboxylic acids. In this study, equilibrium and kinetic data were obtained for reactive extraction of pyruvic acid using trioctylamine (TOA) or Alamine 336 in 1-octanol or oleyl alcohol. The results showed that, without pH adjustment in the aqueous phase, and without the use of an extractant, 1-octanol extracted more pyruvic acid than oleyl alcohol with a distribution coefficient (KD) of 0.30. This trend remained the same when tertiary amines were used as an extractant. The KD values did not significantly differ with TOA or Alamine 336. The recovery of pyruvic acid was observed to increase as a function of TOA concentration and the stoichiometry of the reaction was mainly 1:1. As tertiary amines react only with undissociated acids, an increase in the initial pH of the aqueous phase lowered the KD values. When the pH was 4.0, the effect of TOA concentration on pyruvic acid extraction disappeared and for all concentration levels a distribution coefficient of 0.10 was obtained. Kinetic measurements showed that the reaction between pyruvic acid and TOA in 1-octanol is first order with respect to the two reactants with a rate constant of 0.94 L mol–1 s–1. The enhancement factor was calculated as 25. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200625q Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Natural nontoxic solvents for recovery of picolinic acid by reactive extraction Type de document : texte imprimé Auteurs : Mangesh D. Waghmare, Auteur ; Kailas L. Wasewar, Auteur ; Shriram S. Sonawane, Auteur Année de publication : 2012 Article en page(s) : pp. 13526–13537 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nontoxic solvents Résumé : Pyridine carboxylic acids and their derivatives are attracting considerable attention for their presence in many natural products. 2-Pyridinecarboxylic acid, also known as picolinic acid is widely used in the pharmaceutical industries. Compared to chemical methods, enzymatic oxidation of 3-hydroxyanthranillic acid is an advantageous alternative for the production of picolinic acid. Reactive extraction is a promising method to recover carboxylic acid but suffers from toxicity problems of the diluent and extractant employed, therefore there is a need for a nontoxic extractant and diluent or a combination of less toxic extractants in a nontoxic diluent that can recover acid efficiently. The present paper focuses on the reactive extraction of picolinic acid using tri-n-butyl phosphate (TBP) in sunflower oil and castor oil. Results were presented in terms of distribution coefficients (0.0066 to 0.664 for sunflower oil and 0.0099 to 0.94 for castor oil), loading ratio ( DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201228u
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13526–13537[article] Natural nontoxic solvents for recovery of picolinic acid by reactive extraction [texte imprimé] / Mangesh D. Waghmare, Auteur ; Kailas L. Wasewar, Auteur ; Shriram S. Sonawane, Auteur . - 2012 . - pp. 13526–13537.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13526–13537
Mots-clés : Nontoxic solvents Résumé : Pyridine carboxylic acids and their derivatives are attracting considerable attention for their presence in many natural products. 2-Pyridinecarboxylic acid, also known as picolinic acid is widely used in the pharmaceutical industries. Compared to chemical methods, enzymatic oxidation of 3-hydroxyanthranillic acid is an advantageous alternative for the production of picolinic acid. Reactive extraction is a promising method to recover carboxylic acid but suffers from toxicity problems of the diluent and extractant employed, therefore there is a need for a nontoxic extractant and diluent or a combination of less toxic extractants in a nontoxic diluent that can recover acid efficiently. The present paper focuses on the reactive extraction of picolinic acid using tri-n-butyl phosphate (TBP) in sunflower oil and castor oil. Results were presented in terms of distribution coefficients (0.0066 to 0.664 for sunflower oil and 0.0099 to 0.94 for castor oil), loading ratio ( DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201228u Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : On the subgrid behavior of accelerated riser flows for a high stokes number particulate Type de document : texte imprimé Auteurs : Christian C. Milioli, Auteur ; Fernando E. Milioli, Auteur Année de publication : 2012 Article en page(s) : pp. 13538-13544 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Riser Résumé : We carried out two-fluid highly resolved subgid simulations (SGS) to investigate the effective hydrodynamics of solid phases in riser flows. We considered a high Stokes number articulate, solid hold-ups and gas velocities typical of circulating Fluidized bed combustors and gasifiers (CFBC-G), namely a 520 μm size and 2620 kg/m3 density particulate, average solid fractions from 0.015 to 0.09, and gas velocities from about 3 to 9 m/s. Periodic boundaries were applied in the gravitational direction with the flow driving force provided by an additional gas phase pressure gradient chosen to exceed the gravity acting on the local gas-solid mixture. As a consequence, the simulations produced transient accelerated flows, giving rise to instantaneous field predictions and volume averaged effective parameters at growing gas velocities. The results showed significant effects of both gas velocity and solid bold-up over the flow topology, over the effective stresses and pressure of the solid phase, and over the effective drag. A reasonable agreement was found with a few empirical data that were available for effective shear stresses and effective drag. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267512
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13538-13544[article] On the subgrid behavior of accelerated riser flows for a high stokes number particulate [texte imprimé] / Christian C. Milioli, Auteur ; Fernando E. Milioli, Auteur . - 2012 . - pp. 13538-13544.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13538-13544
Mots-clés : Riser Résumé : We carried out two-fluid highly resolved subgid simulations (SGS) to investigate the effective hydrodynamics of solid phases in riser flows. We considered a high Stokes number articulate, solid hold-ups and gas velocities typical of circulating Fluidized bed combustors and gasifiers (CFBC-G), namely a 520 μm size and 2620 kg/m3 density particulate, average solid fractions from 0.015 to 0.09, and gas velocities from about 3 to 9 m/s. Periodic boundaries were applied in the gravitational direction with the flow driving force provided by an additional gas phase pressure gradient chosen to exceed the gravity acting on the local gas-solid mixture. As a consequence, the simulations produced transient accelerated flows, giving rise to instantaneous field predictions and volume averaged effective parameters at growing gas velocities. The results showed significant effects of both gas velocity and solid bold-up over the flow topology, over the effective stresses and pressure of the solid phase, and over the effective drag. A reasonable agreement was found with a few empirical data that were available for effective shear stresses and effective drag. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267512 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Experimental investigation on the performances on the shell side of shell - and - tube heat exchangers with multiparallel channels Type de document : texte imprimé Auteurs : Wen-Liang Zeng, Auteur ; Zheng-Guo Zhang, Auteur Année de publication : 2012 Article en page(s) : pp. 13545-13553 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Heat exchanger Résumé : This paper presents an experimental investigation on the local surface heat-transfer coefficient on the shell side of a longitudinal-flow shell-and-tube heat exchanger with a multiparallel channel (MPC) inlet and outlet. Under the conditions of with or without a fluid flow distributor (FDB) in the inlet region of the heat exchanger, some characteristics (such as the local Nussult number (Nu) distribution, local-mean Nu distribution, overall heat-transfer performance, and pressure drop) were investigated. The investigation results reveal the distribution of the local surface Nu value in the inlet region, and they give a reasonable mechanism analysis. It was suggested that not only the uniformity of both the fluid flow and the local Nu distribution was effectively improved by FDBs, but also that the global heat-transfer surface Nu value of the heat exchanger was enhanced by more than 10% with the pressure drop increasing slightly by FDBs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267513
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13545-13553[article] Experimental investigation on the performances on the shell side of shell - and - tube heat exchangers with multiparallel channels [texte imprimé] / Wen-Liang Zeng, Auteur ; Zheng-Guo Zhang, Auteur . - 2012 . - pp. 13545-13553.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13545-13553
Mots-clés : Heat exchanger Résumé : This paper presents an experimental investigation on the local surface heat-transfer coefficient on the shell side of a longitudinal-flow shell-and-tube heat exchanger with a multiparallel channel (MPC) inlet and outlet. Under the conditions of with or without a fluid flow distributor (FDB) in the inlet region of the heat exchanger, some characteristics (such as the local Nussult number (Nu) distribution, local-mean Nu distribution, overall heat-transfer performance, and pressure drop) were investigated. The investigation results reveal the distribution of the local surface Nu value in the inlet region, and they give a reasonable mechanism analysis. It was suggested that not only the uniformity of both the fluid flow and the local Nu distribution was effectively improved by FDBs, but also that the global heat-transfer surface Nu value of the heat exchanger was enhanced by more than 10% with the pressure drop increasing slightly by FDBs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267513 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : New correlation for mass transfer characteristics of spray column Type de document : texte imprimé Auteurs : Tsubsa Tanda, Auteur ; Koichi Shirai, Auteur ; Yukihiko Matsumura, Auteur Année de publication : 2012 Article en page(s) : pp. 13554-13560 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Spray tower Mass transfer Correlation analysis Résumé : This paper presents a study of the mass transfer characteristics of a spray column being used as a dehumidification device for air. The experiment was conducted using high humidity air and polyethylene glycol (PEG) as a desiccant solution over a range of process conditions including various liquid flow rates, gas flow rates, water concentrations of PEG, temperatures of PEG, and nozzle diameters. The performance of the spray column was evaluated in terms of volumetric mass transfer coefficients. The results were well expressed by the correlation using dimensionless groups including the physical properties of the liquid and nozzle diameter. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267514
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13554-13560[article] New correlation for mass transfer characteristics of spray column [texte imprimé] / Tsubsa Tanda, Auteur ; Koichi Shirai, Auteur ; Yukihiko Matsumura, Auteur . - 2012 . - pp. 13554-13560.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13554-13560
Mots-clés : Spray tower Mass transfer Correlation analysis Résumé : This paper presents a study of the mass transfer characteristics of a spray column being used as a dehumidification device for air. The experiment was conducted using high humidity air and polyethylene glycol (PEG) as a desiccant solution over a range of process conditions including various liquid flow rates, gas flow rates, water concentrations of PEG, temperatures of PEG, and nozzle diameters. The performance of the spray column was evaluated in terms of volumetric mass transfer coefficients. The results were well expressed by the correlation using dimensionless groups including the physical properties of the liquid and nozzle diameter. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267514 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Thermodynamic preparation window of alpha calcium sulfate hemihydrate from calcium sulfate dihydrate in non - electrolyte glycerol – water solution under mild conditions Type de document : texte imprimé Auteurs : Baohong Guan, Auteur ; Guangming Jiang, Auteur ; Hailu Fu, Auteur Année de publication : 2012 Article en page(s) : pp. 13561-1356 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Electrolyte Preparation Résumé : Through vapor pressure measurements, water activities of the glycerol-water solution were first examined under temperatures of 30―85 °C and glycerol concentrations of 0―50 mol %. The water activity is the only determinant of phase-transition point among CaSO4·2H2O (DH), α-CaSO4·0.5H2O (α-HH), and CaSO4 (AH) in glycerol-water solution. Accordingly, a phase-transition diagram was constructed as a function of temperature (0―140 °C) and glycerol concentration (0―50 mol %), which provided a thermodynamic preparation window of α-HH from DH. Controlling glycerol concentration and temperature within the window, direct transition of DH to α-HH can be regnlated. However, the window is apt to shrink as the operating time is shortened, indicating that its available profile is directed by transition kinetics ofDH to α-HH besides transition thermodynamics. Overall, the glycerol―water solution could act as a novel category of nonelectrolyte medium for α-HH preparation from DH. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267515
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13561-1356[article] Thermodynamic preparation window of alpha calcium sulfate hemihydrate from calcium sulfate dihydrate in non - electrolyte glycerol – water solution under mild conditions [texte imprimé] / Baohong Guan, Auteur ; Guangming Jiang, Auteur ; Hailu Fu, Auteur . - 2012 . - pp. 13561-1356.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13561-1356
Mots-clés : Electrolyte Preparation Résumé : Through vapor pressure measurements, water activities of the glycerol-water solution were first examined under temperatures of 30―85 °C and glycerol concentrations of 0―50 mol %. The water activity is the only determinant of phase-transition point among CaSO4·2H2O (DH), α-CaSO4·0.5H2O (α-HH), and CaSO4 (AH) in glycerol-water solution. Accordingly, a phase-transition diagram was constructed as a function of temperature (0―140 °C) and glycerol concentration (0―50 mol %), which provided a thermodynamic preparation window of α-HH from DH. Controlling glycerol concentration and temperature within the window, direct transition of DH to α-HH can be regnlated. However, the window is apt to shrink as the operating time is shortened, indicating that its available profile is directed by transition kinetics ofDH to α-HH besides transition thermodynamics. Overall, the glycerol―water solution could act as a novel category of nonelectrolyte medium for α-HH preparation from DH. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267515 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : On the influencing factors and strengthening mechanism for thermal conductivity of nanofluids by molecular dynamics simulation Type de document : texte imprimé Auteurs : Wenzheng Cui, Auteur ; Minli Bai, Auteur ; Jizu Lv, Auteur Année de publication : 2012 Article en page(s) : pp. 13568–13575 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanofluids Dynamics simulation Résumé : Compared with conventional single-phase working fluids, nanofluids possess significantly increased thermal conducting properties, but the mechanism for the increase still lacks perfect theory to explain. The aim of this study was to investigate effects of various influencing factors and determine the strengthening mechanism for thermal conductivity of nanofluids by Molecular Dynamics simulations. Thermal conductivities of nanofluids containing nanoparticles with different materials, volume concentrations, and shapes were calculated based on the Green–Kubo formula. Besides, Radical Distribution Function was first applied to nanofluids to analyze the microstructure. In addition, micromotions of nanoparticles were investigated thoroughly by statistical analysis. It was found for the first time that the effects of influencing factors for thermal conductivity of nanofluids can be explained and forecasted by comparing the proportion of energetic atoms containing in different nanoparticles. The changed microstructure of nanofluids is a newly discovered mechanism, and combined with the micromotions of nanoparticles they are proposed to be the main mechanism for strengthening thermal conductivity of nanofluids. The present work indicates that analyzing the proportion of energetic atoms can be an effective way for predicting thermal conducting properties of nanofluids and suggests the main mechanism for thermal conductivity increase which is the basis of developing new heat transfer theory for nanofluids. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201307w
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13568–13575[article] On the influencing factors and strengthening mechanism for thermal conductivity of nanofluids by molecular dynamics simulation [texte imprimé] / Wenzheng Cui, Auteur ; Minli Bai, Auteur ; Jizu Lv, Auteur . - 2012 . - pp. 13568–13575.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13568–13575
Mots-clés : Nanofluids Dynamics simulation Résumé : Compared with conventional single-phase working fluids, nanofluids possess significantly increased thermal conducting properties, but the mechanism for the increase still lacks perfect theory to explain. The aim of this study was to investigate effects of various influencing factors and determine the strengthening mechanism for thermal conductivity of nanofluids by Molecular Dynamics simulations. Thermal conductivities of nanofluids containing nanoparticles with different materials, volume concentrations, and shapes were calculated based on the Green–Kubo formula. Besides, Radical Distribution Function was first applied to nanofluids to analyze the microstructure. In addition, micromotions of nanoparticles were investigated thoroughly by statistical analysis. It was found for the first time that the effects of influencing factors for thermal conductivity of nanofluids can be explained and forecasted by comparing the proportion of energetic atoms containing in different nanoparticles. The changed microstructure of nanofluids is a newly discovered mechanism, and combined with the micromotions of nanoparticles they are proposed to be the main mechanism for strengthening thermal conductivity of nanofluids. The present work indicates that analyzing the proportion of energetic atoms can be an effective way for predicting thermal conducting properties of nanofluids and suggests the main mechanism for thermal conductivity increase which is the basis of developing new heat transfer theory for nanofluids. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201307w Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : A new quartic equation of state based on a general form and its application to pure fluids Type de document : texte imprimé Auteurs : Daxue Li, Auteur ; Jingjing Cao, Auteur ; Zhi Yun, Auteur Année de publication : 2012 Article en page(s) : pp. 13576-13584 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamic properties Equations of state Résumé : A new quartic equation of state (EOS) based on a general form is proposed. Parameters in the new equation are regressed as substance-specific constants for 88 pure substances. The calculated saturated properties for nonpolar and polar substances are compared with experimental data and with that obtained by the Peng―Robinson Stryjek―Vera (PRSV), Patel―Teja (PT), and Yun EOSs for the various pure substances. Despite its simplicity, the proposed equation has good predictive capability over the entire temperature region. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267517
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13576-13584[article] A new quartic equation of state based on a general form and its application to pure fluids [texte imprimé] / Daxue Li, Auteur ; Jingjing Cao, Auteur ; Zhi Yun, Auteur . - 2012 . - pp. 13576-13584.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13576-13584
Mots-clés : Thermodynamic properties Equations of state Résumé : A new quartic equation of state (EOS) based on a general form is proposed. Parameters in the new equation are regressed as substance-specific constants for 88 pure substances. The calculated saturated properties for nonpolar and polar substances are compared with experimental data and with that obtained by the Peng―Robinson Stryjek―Vera (PRSV), Patel―Teja (PT), and Yun EOSs for the various pure substances. Despite its simplicity, the proposed equation has good predictive capability over the entire temperature region. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267517 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Synthesis of Cd hydroxide particles with hollow structures by a one - step process Type de document : texte imprimé Auteurs : Ying Tian, Auteur ; Xin Cui, Auteur ; Fangming Jin, Auteur Année de publication : 2012 Article en page(s) : pp. 13585–13588 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydroxide Résumé : Cd4Cl3(OH)5 particles, for use as a CdS photocatalyst precursor with hollow morphology, were successfully synthesized at room temperature via a one-step process, using boric acid or sodium borate as a buffer. The identification of the morphology and characterization of synthesized particles by high-resolution transmission electron microscopy coupled with energy-dispersive X-ray analysis (HR-TEM/EDX) and X-ray diffraction (XRD) revealed that Cd4Cl3(OH)5 was the main compound. with a size of 40–100 nm, and boron was mostly concentrated on the shell covering nanosized Cd4Cl3(OH)5 particles. Compared with the traditional synthetic methods, this approach has benefits of direct, easy synthesis without the need for additional treatment. It is suggested that boron should play an important role in the synthesis of hollow morphology. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201518t
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13585–13588[article] Synthesis of Cd hydroxide particles with hollow structures by a one - step process [texte imprimé] / Ying Tian, Auteur ; Xin Cui, Auteur ; Fangming Jin, Auteur . - 2012 . - pp. 13585–13588.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13585–13588
Mots-clés : Hydroxide Résumé : Cd4Cl3(OH)5 particles, for use as a CdS photocatalyst precursor with hollow morphology, were successfully synthesized at room temperature via a one-step process, using boric acid or sodium borate as a buffer. The identification of the morphology and characterization of synthesized particles by high-resolution transmission electron microscopy coupled with energy-dispersive X-ray analysis (HR-TEM/EDX) and X-ray diffraction (XRD) revealed that Cd4Cl3(OH)5 was the main compound. with a size of 40–100 nm, and boron was mostly concentrated on the shell covering nanosized Cd4Cl3(OH)5 particles. Compared with the traditional synthetic methods, this approach has benefits of direct, easy synthesis without the need for additional treatment. It is suggested that boron should play an important role in the synthesis of hollow morphology. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201518t Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
