Asbestos fibre

Asbestos-cement was the first FRC composite in modern times, and was used extensively as a cladding material, for roofing and wall units as well as pipes. The asbestos fibres are made of natural crystalline fibrous minerals, consisting of bundles of filaments (sometimes known as fibrils), with individual filaments being as thin as 0.1 /tm or less. In the manufacture of the actual composite, the bundles tend to be split up during the processing procedure, though considerable portions of the reinforcement remain in the form of small fibre bundles. 

The technical and economic success of asbestos-cement in the past has been largely the result of the compatibility between the fibres and the cement matrix. This is due to the high modulus of elasticity and strength of the fibres, and to 

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The resistance of PTFE to creep can be improved by blending in up to 25% of glass or asbestos fibre using PTFE dispersions as mentioned in the previous section. By the same technique alumina, silica and lithia may be incorporated to... 

Of the fibrous fillers which greatly reduce the brittleness, blue asbestos fibre is normally used for battery boxes, the principal outlet. Other materials that may be used include cotton fibres, ground wood, slag wool and ground cork. 

Talc (containing no asbestos fibres) Talc (containing asbestos fibres) 1 2 (respirable du Use asbestos TLV-TWA... 

Asbestos fibres in air Asbestos in bulk material Azodicarbonamide in air Benzene in air... 

This class of material does not set and must be held in position by a rigid cement or some mechanical means. A material commonly used is asbestos fibre mixed with various other substances such as china clay, sand, etc. and plasticised with some form of oil or tar. 

Continuous filament glass fibres Respirable Inhalable Glass wool fibres Rock wool fibres Stag wool fibres Special purpose glass fibres Talc (containing no asbestos fibres)... 

Johnson, N.F. and Davies, R. (1981). An ultrastructural study of the effect of asbestos fibres on cultured peritoneal macrophages. Br. J. Exp. Path. 62, 559-570. 

Mossman, B.T. and Marsh, J.P. (1985). Mechanisms of cell toxic injury by asbestos fibres role of oxygen free radicals. In In vitro Effects of Mineral Dusts (eds. E.G. Beck and J. Bignon) pp. 66-81. Springer Verlag, Berlin. 

Yano, E, Takeuchi, A., Yukiyamo, Y. and Brown, R.C. (1984). Chemotactic fector generation by asbestos. Fibre type differences and the effects of leaching. Br. J. Exp. Pathol. 65, 223-229. 

Talc (containing asbestos fibres)1 11 Tantalum metal and oxide dusts Use asbestos TLV-TWA ,U 5 ... 

Fibres are added to rubbers for a number of reasons. Asbestos fibres were used in such products as brake linings, but their use has been discontinued in the rubber industry due to health and safety considerations. 

There are two main types of proficiency testing scheme. First, there are those set up to assess the competence of a group of laboratories to undertake a very specific analysis, e.g. lead in blood or the number of asbestos fibres in air collected on membrane filters. Secondly, there are those schemes used to evaluate the performance of laboratories across a certain sector for a particular type of analysis. Because of the wide range of possible analyte/matrix combinations it is not practicable to assess the performance of laboratories when analysing all the possible sample types. Instead, a representative cross-section of analyses is chosen (e.g. determination of different pesticide residues in a range of foodstuffs or the determination of trace levels of metals in water samples). 

RICE (Regular Interlaboratory Health and Safety Asbestos fibre counting in the... 

Materials Required Sodium chloride 0.25 g 5% w/v silver nitrate in DW (+ 2-3) drops of cone. HN03 dilute nitric acid (6 N) asbestos fibre. 

To separate solids from a liquid, filtering through paper filters (smooth or fluted) is employed. Cotton wool, asbestos fibres, glass wool, crushed coal, porous glass, and a number of other materials can also be used as filters. The liquid separated in filtration is called the filtrate. 

Silicone rubber in combination with asbestos fibre can be used in pressure reducers in receivers. In comparison tests all diaphragms from organic rubbers and asbestos cease operation due to aging after 200-360 thousand cycles on the other hand, diaphragms from silicone rubber are still in perfect state after 1 million cycles. We should also mention the use of silicone rubbers in industrial furnaces and various apparatuses operating at high temperatures (oil cracking towers, gas pipelines, recuperation installations). 

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