Cloud point and microemulsion phase behavior of sodium linear alkylbenzene sulfonate with tetrabutyl- and benzyltributyl-substituted ammonium halides / Deeleep K. Rout in Industrial & engineering chemistry research, Vol. 48 N° 19 (Octobre 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 19 (Octobre 2009) . - pp. 8842–8847 Titre : Cloud point and microemulsion phase behavior of sodium linear alkylbenzene sulfonate with tetrabutyl- and benzyltributyl-substituted ammonium halides Type de document : texte imprimé Auteurs : Deeleep K. Rout, Auteur ; Siddharth Chauhan, Auteur ; Ashwani Agarwal, Auteur Année de publication : 2009 Article en page(s) : pp. 8842–8847 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cloud point phenomenon Binary water−  anionic surfactant Organic salts Résumé : We report cloud point phenomenon in binary water−anionic surfactant (sodium linear alkylbenzene sulfonate, NaLAS) after incorporation of organic salts, such as tetrabutyl- and benzyltributyl- ammonium halides. The effect of alkyl/aromatic hydrophobic substituents of such reagents on the cloud point phenomenon was also investigated. It was observed that the aqueous solution clouding behavior is dependent upon surfactant concentration, type of hydrophobic substituent of the salt, and operating temperature. At a given temperature, with increasing surfactant concentration, a higher amount of salt is required for the onset of clouding. Besides, at a given surfactant concentration, the amount of salt required for the cloud point is inversely proportional to the temperature. With addition of an oil phase to the binary water(salt)−surfactant system, a three-phase microemulsion could be generated. Phase diagrams for these ternary systems were determined, and the formation of the microemulsion phase behavior was established from phase visualization and oil−water interfacial tension measurements. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801873f [article] Cloud point and microemulsion phase behavior of sodium linear alkylbenzene sulfonate with tetrabutyl- and benzyltributyl-substituted ammonium halides [texte imprimé] / Deeleep K. Rout, Auteur ; Siddharth Chauhan, Auteur ; Ashwani Agarwal, Auteur . - 2009 . - pp. 8842–8847. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 19 (Octobre 2009) . - pp. 8842–8847 Mots-clés : Cloud point phenomenon Binary water−  anionic surfactant Organic salts Résumé : We report cloud point phenomenon in binary water−anionic surfactant (sodium linear alkylbenzene sulfonate, NaLAS) after incorporation of organic salts, such as tetrabutyl- and benzyltributyl- ammonium halides. The effect of alkyl/aromatic hydrophobic substituents of such reagents on the cloud point phenomenon was also investigated. It was observed that the aqueous solution clouding behavior is dependent upon surfactant concentration, type of hydrophobic substituent of the salt, and operating temperature. At a given temperature, with increasing surfactant concentration, a higher amount of salt is required for the onset of clouding. Besides, at a given surfactant concentration, the amount of salt required for the cloud point is inversely proportional to the temperature. With addition of an oil phase to the binary water(salt)−surfactant system, a three-phase microemulsion could be generated. Phase diagrams for these ternary systems were determined, and the formation of the microemulsion phase behavior was established from phase visualization and oil−water interfacial tension measurements. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801873f

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Response of multilayer foundation system beneath railway track under cyclic loading / Deepankar Choudhury in Journal of geotechnical and geoenvironmental engineering, Vol. 134 N°10 (Octobre 2008)  

Public ISBD [article]  inJournal of geotechnical and geoenvironmental engineering > Vol. 134 N°10 (Octobre 2008) . - pp. 1558–1563 Titre : Response of multilayer foundation system beneath railway track under cyclic loading Type de document : texte imprimé Auteurs : Deepankar Choudhury, Auteur ; Rajeev Kumar Bharti, Auteur ; Siddharth Chauhan, Auteur Année de publication : 2008 Article en page(s) : pp. 1558–1563 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Railroad tracks Dynamic models Cyclic loads Subgrades Ballast Displacement Foundations Résumé : For an efficient and economical design of a railway track system, it is necessary to understand the behavior of each track component with special reference to ballast and subgrade, which play a pivotal role in distributing the large, cyclic wheel loads longitudinally, laterally, and vertically away from the wheel contact area on the rail surface to the underlying soil strata. This paper presents an analytical model of a track-ballast-subgrade system with different formation soils such as dense uniform sand, stiff clay, loose sand, and soft clay modeled by using a mass-spring dashpot system with two degrees of freedom. This represents the varying energy distribution through ballast and subgrade in the vertical direction. Results are presented in the form of time-displacement response profiles for both the ballast and subgrade layers. In addition, the magnification factors for displacements with variation in subgrade soils for cyclic loading frequencies are reported. It is observed that the results obtained from the present analysis follow the experimentally observed trends already available in the literature. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A10%281 [...] [article] Response of multilayer foundation system beneath railway track under cyclic loading [texte imprimé] / Deepankar Choudhury, Auteur ; Rajeev Kumar Bharti, Auteur ; Siddharth Chauhan, Auteur . - 2008 . - pp. 1558–1563. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N°10 (Octobre 2008) . - pp. 1558–1563 Mots-clés : Railroad tracks Dynamic models Cyclic loads Subgrades Ballast Displacement Foundations Résumé : For an efficient and economical design of a railway track system, it is necessary to understand the behavior of each track component with special reference to ballast and subgrade, which play a pivotal role in distributing the large, cyclic wheel loads longitudinally, laterally, and vertically away from the wheel contact area on the rail surface to the underlying soil strata. This paper presents an analytical model of a track-ballast-subgrade system with different formation soils such as dense uniform sand, stiff clay, loose sand, and soft clay modeled by using a mass-spring dashpot system with two degrees of freedom. This represents the varying energy distribution through ballast and subgrade in the vertical direction. Results are presented in the form of time-displacement response profiles for both the ballast and subgrade layers. In addition, the magnification factors for displacements with variation in subgrade soils for cyclic loading frequencies are reported. It is observed that the results obtained from the present analysis follow the experimentally observed trends already available in the literature. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A10%281 [...]

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