http://nopr.niscair.res.in/handle/123456789/8564 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/8634 Title: A mass transfer model for the prediction of permeate concentration during ultrafiltration of methyl violet dye solution <br/> <br/>Authors: Chatterjee, S; Acharjee, D K <br/> <br/>Abstract: A mass transfer model is proposed for prediction of permeate concentration and percent rejection at different inlet pressures and feed dye concentrations in membrane ultrafiltration. A differential equation in cylindrical co-ordinates considering the spiral wound membrane equivalent to a cylindrical module is derived which coupled with mass balance and permeate flux equations are solved to yield the theoretical permeate concentration. As the mass transfer coefficient used from literature gave high values for predicted permeate concentration, an empirical correlation for mass transfer coefficient was obtained based on experimental data on the dissolution of solid in aqueous solution from the wall of a hollow cylindrical tube where the mass transfer occurred in the boundary layer. The experimental permeate concentrations agreed reasonably well with those predicted from the model developed. <br/> <br/>Page(s): 205-211 Sat, 26 Feb 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/8633 Title: Inhibition of mild steel corrosion by oleochemical based hydrazides <br/> <br/>Authors: Quraishi, M A; Saxena, N; Jamal, D <br/> <br/>Abstract: Selected hydrazides of fatty acids with C₉–C₁₇carbon atoms have been synthesized and evaluated as corrosion inhibitors of mild steel (MS) in hydrochloric acid (HCl) solutions by weight loss and potentiodynamic polarization methods. The adsorption of all the hydrazides on mild steel surface in the acid solution has been found to obey Langmuir's adsorption isotherm. The potentiodynamic polarization studies revealed that all compounds block the corrosion reactions. Inhibition efficiency (IE) of these compounds has been found to vary with the concentration of the compound, solution temperature, immersion time and concentration of the acid solution. The values of activation energy (<i>E</i>_a<i>)</i> and free energy of adsorption (Δ<i>G</i>_ads) have been calculated to investigate the mechanism of the corrosion inhibition. <br/> <br/>Page(s): 220-224 Sat, 26 Feb 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/8632 Title: Assay of bromhexine hydrochloride in pharmaceutical formulations by extraction spectrophotometry <br/> <br/>Authors: Rao, S V Murali Mohan; Rao, I Nageswara; Reddy, T Rama Subba; Sastry, C S P <br/> <br/>Abstract: Three simple and sensitive spectrophotometric methods (A-C) for the assay of bromhexine hydrochloride in pure and dosage forms based on the formation of chloroform soluble ion-associates under specified experimental conditions are described. Three acidic dyes, namely, Tropaeolin oo (TP oo, method A), Naphthalene blue 12BR (NB 12BR, method B) and Azocarmine G (ACG, method C) are utilized. The extracts of the ion-associates exhibit absorption maxima at 420, 620 and 540 nm for methods A, B and C respectively. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges (2.0-10) <img src='/image/spc_char/micro.gif' border=0> g/mL for method A, (5.0-25) <img src='/image/spc_char/micro.gif' border=0> g/mL for methods B and C respectively. Beer’s law and the precision and accuracy of the methods are checked by the UV reference method. The results are reproducible with an accuracy of ± 1.0%. The methods are found to be suitable for the determination of bromhexine hydrochloride in the presence of the other ingredients that are usually present in dosage forms. <br/> <br/>Page(s): 170-174 Sat, 26 Feb 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/8631 Title: Determination of heavy metals in selected drug substances by inductively coupled plasma – mass spectrometry <br/> <br/>Authors: Murty, A S R Krishna; Kulshresta, U C; Rao, T Nageswara; Talluri, M V N Kumar <br/> <br/>Abstract: Heavy metal contents in dicyclomineHCl, ethambutol, pyrazinamide and furazolidone drugs were determined by inductively coupled plasma (ICP) - mass spectrometry (MS). The drugs were analyzed for Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg, Pb metals by selecting a suitable isotope. Cr, Fe, Ti and Cu were observed to be highest in dicyclomineHCl, ethambutol, pyrazinamide and furazolidone respectively. Ni and Hg were absent in all the four drugs, while traces of Cd were present in ethambutol and pyrazinamide. Analytical results showed that ICP-MS method is useful for monitoring inorganic impurities present in such drugs. <br/> <br/>Page(s): 229-231 Sat, 26 Feb 2005 22:58:59 GMT