NOPR Collection:

Preparation of mixed oxide supports by homogeneous precipitation method

1994-01-01T00:00:00Z

Title: Preparation of mixed oxide supports by homogeneous precipitation method Authors: Reddy, B Mahipal; Madhavend, S S; Reddy, E Padmanabha Abstract: Preparation of catalytically important TiO₂–Al₂O₃, TiO₂- SiO₂, TiO₂ -ZrO₂, TiO₂ -SiO₂ -ZrO₂ and SiO₂ -ZrO₂ mixed oxides by coprecipitation method using urea as hydrolyzing agent is described. These mixed oxides are X-ray amorphous and exhibit high N₂BET surface areas. Page(s): 60-62

Photoelectrochemical studies of sprayed thin film n- ZnO/acetonitrile based photocell sensitized by rhodamine B

1994-01-01T00:00:00Z

Title: Photoelectrochemical studies of sprayed thin film n- ZnO/acetonitrile based photocell sensitized by rhodamine B Authors: Bahadur, Lal; Pandey, J P Abstract: Photoelectrochemical cell based on thin film ZnO electrode sensitized by rhodamine B (Rh B) has been studies in acetonitrile medium using hydroquinone as supersesitizer. Redox potentials of Rh B determined cyclic voltammetrically at Pt electrode in acetonitrile, coupled with the flat-band potential of ZnO electrode (obtained from Mott-Schottky plot) have been used to determine their respective energy levels. Stable photovolrage was found to be -260 mV. Quantum efficiency of the sensitized photocurrent at 550 nm wavelength of monochromatic light was found to be 6.5%, the highest ever reported for pure ZnO electrode sensitized by Rh B. Long-term stability of ZnO electrode in the medium of investigation has been tested and quite encouraging results have been obtained. Page(s): 53-59

Synthesis, characterization and evaluation of chlorinated soybean oil alkyds

1994-01-01T00:00:00Z

Title: Synthesis, characterization and evaluation of chlorinated soybean oil alkyds Authors: Bhandari, S; Chandra, S Abstract: The chlorinated alkyds were synthesized by the direct chlorination of the soybean oil alkyds of 55% oil length in carbon tetrachloride. Five samples of chlorinated alkyds, varying in the chlorine content from 11.8 to 50.8%, were synthesized in order to study the effect of chlorine. It was confirmed through IR spectroscopy that chlorine enters only into the aliphatic portion of the alkyd molecule by addition and substitution reactions. Thermal stability of the chlorinated alkyds was found to increase with the chlorine content. In addition to general characterization, the mechanical and chemical film properties of the unchlorinated and chlorinated soybean alkyds were also appraised simultaneously which revealed that, in general, the chlorinated soybean alkyds possessed superior film forming properties as compared to the unchlorinated ones except in terms of flexibility and solvent resistance. Page(s): 45-52

Condensation of a spherical two-phase bubble in an immiscible liquid -A parametric study

1994-01-01T00:00:00Z

Title: Condensation of a spherical two-phase bubble in an immiscible liquid -A parametric study Authors: Wanchoo, R K Abstract: This paper presents a theoretical analysis of the condensation of a single two-phase bubble during its rise in a quiescent column of an immiscible liquid. Governing equations are derived and solved by a numerical method. Dimensionless parameters governing the phenomenon are identified and a parametric study is carried out for different parameters. The predicted results are compared with available experimental data. The bubble collapse rate and Nusselt number are found to be dependent on: Peclet number, system Jakob number and thermal property parameter, K*. Page(s): 40-44