Fibrous asbestos

With decreasing amounts of metal oxide, the degree of polymerisation increases. Chains of linked tetrahedra form, like the long chain polymers with a -C-C- backbone, except that here the backbone is an -Si-O-Si-O-Si- chain (Fig. 16.4c). Two oxygens of each tetrahedron are shared (there are two bridging oxygens). The others form ionic bonds between chains, joined by the MO. These are weaker than the -Si-O-Si- bonds which form the backbone, so these silicates are fibrous asbestos, for instance, has this structure. 

Faser-asbest, m. fibrous asbestos, -asche, /. fiber ash. -bildung, /. fiber formation, fibra-tion. -blende, /. fibrous sphalerite. Faserchen, n. little fiber, fibril, filament. Faserfarbung, /. coloration of the fiber, faserfdrmig, a. fibrous, filiform. 

The Gooch crucible is prepared with a filtering layer of good fibrous asbestos on top of which is placed a perforated porcelain plate. The asbestos should be previously purified by boiling first with aqua regia for a short time, and then with cone, hydrochloric acid for a week, the acid being renewed each day. (J. S. C. I., 38,189.)... 

Soil plays an integral part in our lives and is inherently linked to public health. For example, many of the essential trace elements which we require in our diet to remain healthy are derived from soils and parent rock material, and low concentrations or the unavailability of these elements in soil can cause dietary deficiencies. Soils can also be contaminated with a range of potentially hazardous substances (both chemical and biological) which, if present at sufficiently elevated levels, can present a potential public health problem. For example, soils may contain elevated levels of heavy metals such as cadmium and lead which can have measurable and often severe effects on local populations. The soils of Cappadocia in central Turkey are naturally rich in fibrous asbestos-like minerals that are thought to be the cause of a rare cancer in local communities1 while exposure to the bacterium Clostridium tetani in soils can cause tetanus. Despite such examples, the effects of contaminated land have, until recently, been relatively ignored and, even today, our understanding of the mechanisms and level of risk associated with contaminated land is poor in relation to air and water. 

In the murine alveolar type n cell line, MLE-15, the addition of serum to the culture media reduced the in vitro cristobalite (particle diameter 1.2/ n)-induced chemokine response (i.e., shift in the dose-response curve) as specific serum component, apolipoprotein-Al selectively binds to silica (Barrett et al. 1999). This serum protein also binds to other non-fibrous (Ti02) and fibrous (asbestos) particles. 

Superheating of Vapour.—When the amount of liquid in the still is very small, the vapour is liable to be superheated by the flame, and unless the bulb of the thermometer is thoroughly moistened with condensed liquid, too high a temperature will be registered. If a very little cotton wool, or, for temperatures above 230 , a little fibrous asbestos, be wrapped round the bulb of the thermometer, it remains, as a rule, thoroughly moist, and, with a pure liquid, heated by a naked flame, the thermometer registers a perfectly con-... 

Condensation on the thermometer is promoted by covering it with a little cotton wool (1), or, for high temperatures, fibrous asbestos and, in determining a boiling point or carrying out a distillation with the ordinary apparatus, it is always advisable to cover the thermometer bulb in this way. If the liquid, the boiling point of which is to be determined, is not known to be quite pure, it is advisable to distil a fair... 

There are many more minerals that could be discussed ranging from wollas-tonite, to attapulgite clays, or zeolites. Some mineral zeolites are fibrous asbestos types of crystals. Natrolite, Na2Al2Si30io-2H20, is called Fibrous Zeolite. Zeolites are used extensively in detergents, throughout the world, as a poor substitute for phosphates, but it is unlikely that synthetic zeolites will cause problems as an... 

Double chains Ampliiboles (note the hexagonal ring structures. These include the fibrous asbestos minerals. 

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