Drag on non-spherical particles in power law non-Newtonian media

The free settling velocity of cylinders and disks falling in quiescent Newtonian and power law liquids has been measured over wide ranges of experimental conditions of the particle Reynolds number (10-5-~300), power law flow behaviour index (0.31-1) and the length-to-diameter ratio, ~0.4-~14. The corresponding range of sphericity is 0.62 to 0.86. An existing drag expression which has been tested extensively for spherical particles falling in Newtonian and in power law fluids has been slightly modified here for non-spherical particles. In particular, the use of this drag expression necessitates a knowledge of an equal volume sphere diameter (to evaluate the Reynolds number and drag coefficient) and the ratio of the surface area to the projected area of a non-spherical particle. With these modifications, the approach outlined here reproduces the present and the literature data for a wide range of non-spherical particles including cones, prisms, needles, cylinders settling in both Newtonian and power law fluids with reasonable levels of accuracy

Performance of a sand filter in removal of algal bloom for SWRO pre-treatment

International audienc

Microtitration of Rubella Virus in Monovalent Vaccinal Products

"nBackground: Potency test for control of rubella vaccine is a significant factor to qualify production line and vaccination pro­gram. For this reason, WHO recommends to use the microtitration method by both vaccine companies and control laborato­ries. Then the study was done to improve this test."nMethods: Three rubella virus samples, including an in-house standard, a lot of vaccine and an in- process product, were tit­tered in cell culture tubes. Then micro titration steps were tested on 96-well microplate using cocultivation of standard ru­bella vaccine dilutions and RK- 13 cell line. After 6-7 days, final reading was done and calculated the titer. Two other sam­ples were assayed with the micromethod."nResults: Titer reduction less than 0.5 log was acquired for each sample during frequent tests and between two methods."nConclusion: The procedure was profitable and accurate for potency and identity tests of rubella virus vaccine, on the basis of WHO recommendations. &nbsp