Effect of pulse duration and size of interelectrode interval on electric-spark spraying. I. Effect of pulse duration and size of interelectrode interval on rate of electric-spark transfer

The influence exerted by electric-spark spraying on the kinetics of mass transfer and the physicomechanical properties of coatings is investigated. It is shown that electric-spark spraying is determined by the dynamic properties of the cathode jets, which depend on the electrical parameters of the spark discharge, the size of the interelectrode interval, and the physical properties of the coatings, which vary during spraying.     

Simultaneous visualisation of biofouling, organic and inorganic particle fouling on separation membranes.

Fouling is a major problem in membrane processes of water treatment. It can be caused by the deposition of inorganic and organic particulate material, and of microbial cells which may subsequently form biofilms. In practice, usually more than one foulant participates in the formation of membrane deposits. Knowledge of the composition of fouling layers is important for the development of appropriate countermeasures. For this purpose, an experimental system was established for the generation and microscopic visualisation of mixed deposits, using fluorescently labelled model foulants: (i) drinking-water bacteria stained with nucleic acid-specific dyes (biofouling), (ii) synthetic clay mineral laponite stained with rhodamine 6G (inorganic particle fouling), and (iii) fluorescently labelled polystyrene microspheres (organic particle fouling). Polycarbonate and polyethersulfone membranes were challenged with these foulants by dead-end filtration. On the basis of different fluorescent labels, the single foulants in these mixed deposits could be visualised separately by confocal laser scanning microscopy which, in combination with image analysis, allowed the generation of three-dimensional views of the complete deposits. This method offers the possibility for the estimation of quantitative surface coverage by foulants and for the determination of the efficacy of cleaning measures with respect to the removal of different foulants.     

Ceramics from mining by-products and alumina production wastes

The possibility of obtaining chemically stable ceramics in plastic molding from pastes based on comprehensive use of mining by-products (plagioporphyry, quartz-biotite shale), alumina production wastes (red mud), and polymineral clay was demonstrated. The mechanism of enhancing paste sintering on addition of finely disperse grog-flux and increasing the alkali resistance of the material (to 95%) in molding of the crystalline hematite-anorthite-quartz system was examined. __________ Translated from Steklo i Keramika, No. 2, pp. 17–20, February, 2007.     

Coding techniques for the noisy magnetic recording channel: astate-of-the-art report

Coding techniques for improving the reliability of information storage on noisy magnetic recording channels are considered. It is assumed that the Lorentzian channel model applies and that the retrieved signal is perturbed with additive white Gaussian noise. The immunity against additive noise of state-of-the-art codes such as DC-free, runlength-limited, and trellis codes are assessed     

Electron diffraction study of enzyme-hydrolyzed cotton samples

An electron diffraction study on continuously and repeatedly enzyme-hydrolyzed cotton samples was carried out. The electron diffraction pattern on repeatedly enzyme-treated sample reveals a cellulose I pattern with the absence of the 101 plane. This confirms that enzymatic hydrolysis of cotton fibers proceeds preferentially along the 101 plane, being a clevage plane.     

Biochemical quality assessment of broiler production using a hydrogen bacteria biomass in the diet

The authors studied the biochemical composition of the meat of broilers, eggs, liver and muscles of laying hens of 3 generations on a 5, 10, 25, 50 and 100% (broilers), 10 and 20% (laying hens) replacement of the animal protein quota in the diet by protein obtained from the hydrogen bacteria Alcaligenes eutrophus L-1. No deterioration of the quality of the produce was found from the standpoint of the main biochemical parameters.