NOPR Collection:

Specific deposit evaluation from filter's headloss

Mon, 01 Feb 1999 00:00:00 GMT

Title: Specific deposit evaluation from filter's headloss Authors: Bhargava, Devendra S; Pande, P K Abstract: A simple theoretical approach, based on Ives model for headloss development as a function of specific deposit in filters, has been presented for determining specific deposits from headloss variation versus time plots during the progress of filtration. The evolved model for specific deposit prediction has been tested with experimental data. Page(s): 9-12

Galvanostatic formation and photoelectrochemical characterization of zinc selenide and mercury containing zinc selenide films

Mon, 01 Feb 1999 00:00:00 GMT

Title: Galvanostatic formation and photoelectrochemical characterization of zinc selenide and mercury containing zinc selenide films Authors: Singh, Kehar; Mishra, Sameer S D Abstract: Electrosynthesis of zinc selenide and mercury containing zinc selenide films has been carried out under controlled galvanostatic conditions. For photoelectrochemical characterization of these preparations, photoelectro-convertibility and photoaction spectral behaviour have been investigated. Resistance of these photoelectroactive films towards electrochemical corrosion has also been examined on the basis of polarization studies and Tafel plots. Page(s): 48-52

Quantitative measurement of pigment diffusion by automatic image profile scan technique

Mon, 01 Feb 1999 00:00:00 GMT

Title: Quantitative measurement of pigment diffusion by automatic image profile scan technique Authors: Ohanuzue, C B C; Nobbs, J H Abstract: A technique combining light transmission microscopy with computer analysis of an image profile has been developed for the quantitative measurement of the migration behaviour of pigment molecules dispersed in plasticised poly(vinyl chloride). The technique is based on the interactive hard- and soft-ware programs which generated an analogue to digital conversion of a photometer response to a gamma corrected luminance signal output of the light intensity with decreasing pigment concentration in the direction of the diffusion. This technique provides a precise and quantitative assessment of the suitability of pigments as additives in polymeric systems. Page(s): 43-47

Ignition and combustion studies on metallized UDMH-RFNA bipropellant system

Mon, 01 Feb 1999 00:00:00 GMT

Title: Ignition and combustion studies on metallized UDMH-RFNA bipropellant system Authors: Gupta, B L; Varma, Mohan Abstract: The ignition delay studies on unsymmetrical dimethyl hydrazine gelled with methyl cellulose (4.48 wt%) containing varying amounts of metal powder (Al and Mg) with red fuming nitric acid oxidant have been carried out at and around oxidizerfuel(O/F) ratios corresponding to maximum specific impulse. The minimum ignition delay is registered at a critical O/F ratio which is always less than the respective stoichiometric mixture ratios. Further, the ignition delay is related with theoretical specific impulse and are both found to be inversely related with each other. The minimum ignition delay and critical O/F ratio have been found to vary linearly with metal content of fuel gel. The data on 'heat of combustion' show that it increases linearly with the degree of metallization of gelled fuel and experimental value of 'heat of combustion' is found to be less than its theoretical value. The analysis of data show that the oxide formation in case of aluminium occurs mainly by water vapour-metal interaction and marginally due to direct oxidizer-metal reaction whereas for the oxidation of magnesium only the former mechanism seems to be operative. Page(s): 13-21