Documents disponibles écrits par cet auteur

Controlled crystallization of macromolecules using patterned substrates in a sandwiched plate geometry / Anindita Sengupta Ghatak in Industrial & engineering chemistry research, Vol. 50 N° 23 (Décembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12984–12989 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 [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

Generation of air – water two - phase flow patterns by altering the helix angle in triple helical microchannels / Sambasiva Rao Ganneboyina in Industrial & engineering chemistry research, Vol. 51 N° 27 (Juillet 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9356–9364 Titre : Generation of air – water two - phase flow patterns by altering the helix angle in triple helical microchannels Type de document : texte imprimé Auteurs : Sambasiva Rao Ganneboyina, Auteur ; Animangsu Ghatak, Auteur Année de publication : 2012 Article en page(s) : pp. 9356–9364 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Phase  flow  Microchannels Résumé : Flow of a liquid inside a helical tube is composed of axial and circumferential components, the latter arising because of its specific geometry. For a gas–liquid two-phase flow inside a helical tube, the coupled effect of these two flow components leads to a variety of flow patterns, for example, slug, bubble, and stratified flow. We present here a novel triple-helical microchannel, in which, the two-phase flow is found to engender several additional flow patterns not observed with the conventional geometries, for example, the parallel and oscillating annular flow and even simultaneous occurrence of several such patterns. We show that the transition between these patterns depends not only on the fluid rates of the two liquids but also on the helix angle. We have presented detailed phase diagrams to elaborate these effects. We have examined also the effect of channel geometry on the specific features of these flow patterns. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201249g [article] Generation of air – water two - phase flow patterns by altering the helix angle in triple helical microchannels [texte imprimé] / Sambasiva Rao Ganneboyina, Auteur ; Animangsu Ghatak, Auteur . - 2012 . - pp. 9356–9364. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9356–9364 Mots-clés : Phase  flow  Microchannels Résumé : Flow of a liquid inside a helical tube is composed of axial and circumferential components, the latter arising because of its specific geometry. For a gas–liquid two-phase flow inside a helical tube, the coupled effect of these two flow components leads to a variety of flow patterns, for example, slug, bubble, and stratified flow. We present here a novel triple-helical microchannel, in which, the two-phase flow is found to engender several additional flow patterns not observed with the conventional geometries, for example, the parallel and oscillating annular flow and even simultaneous occurrence of several such patterns. We show that the transition between these patterns depends not only on the fluid rates of the two liquids but also on the helix angle. We have presented detailed phase diagrams to elaborate these effects. We have examined also the effect of channel geometry on the specific features of these flow patterns. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201249g