http://nopr.niscpr.res.in/handle/123456789/22611 2026-10-10T23:53:10Z http://nopr.niscpr.res.in/handle/123456789/22755 Title: Preparation and characterization of lobster shell chitosan: Modification of traditional method Authors: Chatterjee, S; Guha, A K; Chatterjee, B P Abstract: Preparation of chitosan from lobster shells by Hackman method and modified Hackman method was compared with respect to, their physico-chemical properties, molecular weight, degree of deacetylation, polydispersity and crystallinity. In modified method maximum yield (78%) of chitosan with almost 91% degree of deacetylation determined by first derivative UV spectra was achieved. Molecular size distribution as well as average size of chitosan produced by Hackman method was higher (PI 1.205, particle size 1448.6 nm) and of <img src='http://www.niscair.res.in/jinfo/mbar.gif' border=0>_wt 10 ×10⁵ when compared to chitosan produced by modified Hackman method (PI 0.8832, particle size 95.3 nm) of <img src='http://www.niscair.res.in/jinfo/mbar.gif' border=0>_wt 3.98×10⁵. X-ray powdered diffraction showed that chitosan prepared by Hackman method was found to be more crystalline, Bragg refractions 13.3°2θ (d = 6.66Å) and 19.7°2θ (d = 4.51Å), respectively than chitosan produced by modified method, Bragg refraction 13.6°2θ (d = 6.51Å). This method provides quality product in less time and is economical. Page(s): 350-354 2003-07-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/22738 Title: James Dewar — More than a flask Authors: Wisniak, Jaime Abstract: James Dewar (1842-1923) is widely known for his pioneering work in cryogenics, of being the first to achieve the liquefaction of hydrogen, by the flask that carries his name, and by his studies about the behaviour of living organisms and materials under conditions of extreme cold. Although he was an excellent experimentalist, he did not leave many significant theoretical contributions. Page(s): 424-434 2003-07-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/22737 Title: Kinetics of esterification of tri-ethylene glycol-methacrylic acid reaction system Authors: Notay, J S; Bhagade, S S Abstract: Catalysis of esterification reaction of triethylene glycol and methacrylic acid has been reported. A kinetic empirical expression correlating the fractional conversion of methacrylic acid, with catalyst concentration, mole ratio (glycol to methacrylic acid) and temperature is presented for tri-ethylene glycol-methacrylic acid reaction system using methane sulphonic acid and sulphuric acid as homogenous catalyst. Page(s): 420-423 2003-07-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/22736 Title: Effect of substituents on corrosion inhibition efficiency of arylisothiocyanates and their condensation products with thiosemicarbazide for corrosion of copper in aqueous chloride solution Authors: Singh, M M; Rastogi, R B; Upadhyay, B N; Yadav, M Abstract: The inhibition of copper corrosion in 1.5% sodium chloride solution was studied at 25, 35 and 45°C using different concentrations of thiosemicarbazide, <i>p</i>-methoxyphenyl isothiocyanate, <i>p</i>-methylphenyl isothiocyanate and <i>p-</i>chlorophenyl isothiocyanate and their corresponding condensation products with thiosemicarbazide. The inhibition efficiency IE of these compounds was evaluated by weight loss and electrochemical polarisation techniques. Substitution at <i>p</i>-position in the phenyl group resulted in change in IE in the following order for both the aryl isothiocyanates and their corresponding condensation products with thiosemicarbazide-<i>p</i>-chlorophenyl-< phenyl- < <i>p</i>-methylphenyl- <<i>p</i>-methoxyphenyl. Page(s): 414-419 2003-07-01T00:00:00Z