Electron microscopic studies on the useful life of liquid permeated membranes

Morphological changes occurring on the surface of a polyethylene membrane used in liquid permeation of hydrocarbons have been studied by electron microscopy. The upstream surface of the membrane in contact with liquid feed has been shown to be eroded considerably whereas the downstream surface remained sensibly unaffected. Thus, the useful life of a particular membrane is limited depending on temperature and nature and quantity of the feed used.     

Fatty acids of boal fish oil by urea fractionation and gas-liquid chromatography.

The fatty acid composition of body and liver fats of boal, Wallago attu (Schn.), a cat fish, belonging to the family Siluridae and commonly known as fresh-water shark has been determined by urea fractionation and gas–liquid chromatography (g.l.c.). The percentages of major component acids were found to be, 16:0, 10.5; 16:1 ω9, 7.6; 18:0, 7.2; 18:1 ω9, 17.4; 18:2ω9, 8.4; 18:3ω3, 6.1; 20:4ω3, 3.7 and 22:6ω3, 4.4. In addition, a number of minor component acids have been detected and estimated. The liver oil fatty acids have also been determined without fractionation and the percentages of major component acids found were 16:0, 23.5; 18:0, 12.7; 18:1ω9, 7.0; 20:4ω3, 13.7; 22:6ω3, 11.2. The oil has been studied for the first time for its fatty acid composition.     

Vapor sorption characteristics of condensable hydrocarbon vapor in low-density polyethylene

Sorption characteristics of vapors of pure hydrocarbon and their binary mixtures in low-density polyethylene were studied under various conditions of temperature and pressure. A new apparatus devised and utilized for the determination of composition of sorbed vapor in case of binary mixtures is described. The study demonstrates the effect of the presence of one component within the polymer on the sorption of another and also the occurrence of selectivity in sorption.     

Field and carrier current density profiles in linearly graded silicon avalanche diodes

A detailed study for the d.c. field and carrier current density profiles of linearly graded double drift avalanche diodes is presented taking into account the effect of impurity and mobile charge density and the realistic field dependance of the ionization rates and drift velocities for the charge carriers. The study involves finding the location and magnitude of the electric field maximum by an iterative method. A small shift in the position of the electric field maximum towards the p-side of the metallurgical junction is observed which increases with increasing current density and decreasing doping gradient. The maximum field and the depletion layer width change sharply with doping gradient but very slightly with d.c. current density. Over a larger fraction of the depletion layer, hole current density exceeds electron current density and hole dominance increases with decreasing doping gradient. The avalanche centre where J_p = J_n is found to be always on the n-side of the junction.     

Arc-assisted electric discharges in high-pressure carbon monoxide gas mixtures

Continuous arc-assisted electric discharges have been obtained in CO-Ar and CO-N2-Ar gas mixtures at pressures of about 0.1 atm and with maximum discharge loadings of 7.9 and 23 kW/ mole/s, respectively. The discharge technique appears suitable for adaptation to CW, high-power CO lasers.