Working properties

ASTM D883 defines a filler as "...a relatively inert material added to a plastic to modify its strength, permanence, working properties, or other quaHties or to lower costs." EiHers (qv) that modify the properties and characteristics of epoxies are employed in epoxy resins for a variety of reasons. Then principal functions are to control viscosity, reduce shrinkage and the coefficient of thermal expansion, effect a cost reduction, and color the epoxy resins. 

Properties of sodium sulfate help speed up the melting process in glassmaking. Its use reduces the tendency for alkaline gas bubbles to form in the glass and provides a less expensive form of Na20 than soda ash (6). Sodium sulfate improves the working properties of high siUca glasses. 

Edited by Edward Hooker, with preface signed by J.L. (i.e. Jane Lead). Separately title-paged third part A treatise of eternal nature with her seven essential forms, or original working properties, J.P.M.D. London, printed Anno Dom. 1681 pp.[97]-162. This was reprinted 1770 as A compendious view of the grounds of the Teutonic philosophy... 

Mixing molten copper with other metals yields a variety of alloys, such as bronze when alloyed with tin, brass with zinc, and arsenical copper with arsenic (see Table 34 and text below). All these alloys have extremely good mechanical and working properties and have, therefore, been employed for applications requiring strength and hardness (West 1982). 

The discovery of the working properties of clays must have resulted in one of humankind s first expressions of representational art, roughly contemporaneous with the discovery of the colouring properties of natural pigments and their use in cave art. The additional discovery that the result of the manipulation of this art form could be rendered permanent by the use of fire must indeed have been a source of wonder. The earliest fired ceramic so far known is a small moulded figurine from Dolni Vestonice in what was Czechoslovakia, dated to approximately 26000 years BP (Vandiver et al., 1989). By approximately 10000 years ago, simple utilitarian vessels were being produced in the Near and Far East. 

Composition 60% copper, 38% zinc, and 2% lead. Used in hardware and plumbing parts due to its good hot working properties. 

P. It was developed by Chase Division, Kennecott Copper Corp., in 1950. The machinability rating is 80. The hot-working properties are comparable to those of a high copper commercial bronze and are superior to lead-containing free-machining copper alloys. The tensile strength is high, and the electrical and thermal conductivities are similar to those of nickel bronze CDA No. 191, and about one half those of copper (see Copper alloys). 

Aluminium alloys well with up to about 3-5 per cent, of tantalum, which has no effect, however, on the mechanical strength, ductility, and working properties of aluminium.3 Reduction of tantalum pentoxide by the thermite process yields hard, brittle alloys.1 A substance the composition of which corresponds with the formula TaAls has been obtained by reducing potassium tantalum fluoride, K2TaF7, with aluminium filings at a high temperature. It is described as an iron-grey crystalline powder, of density 7-02, which is scarcely attacked by acids.5... 

There is a trend in commercial testing of product quality to introduce non-destructive methods, in other words, tests that leave no defects in the tested materials that would affect their working properties. The use of these methods not only spares products but also permits more frequent testing, and gives better product quality control. This should be considered in the choice of hardness determination method. 

Selenium copper also available for combining high electrical conductivity with free-machining and hoi-working properties. Alloy makes excellent copper-to-glass seals. 

Dense cores increase difficulty in on-site working properties and nailability. 

Even though it has been in use since 1880 pyrocatechin (catechol) is one of the most overlooked developing agents. The working properties of catechol are very much like those of hydroquinone and it can even be used as a substitute for hydroquinone in many formulae, though it works more rapidly than hydroquinone. 

In time both Solution A and B will oxidize, form a precipitate, and turn brown and muddy. This is normal and will not affect the working properties of the formula. 

Fillers are relatively nonadhesive substances added to the adhesive formulation to improve its working properties, strength, permanence, or other qualities. The improvements resulting from the use of fillers are listed in Table 1.8. Fillers are also used to reduce material cost. By selective use of fillers, the properties of an adhesive can be changed significantly. Thermal expansion, electrical and thermal conduction, shrinkage, viscosity, and thermal resistance are only a few properties that can be modified by the use of fillers. Common fillers are wood flour, silica, alumina, titanium oxide, metal powders, china clay and earth, slate dust, and glass fibers. Some fillers may act as extenders. 

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