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Hardness nature

By comparison, temperatures as high as 150°C are often required for mold-enclosed hard natural mbber compounds, where mold plattens are directly heated by steam or electricity. Synthetic latex mbber compounds, however, can be vulcanised at temperatures higher than those for natural mbber neoprene and acrylonitrile—butadiene can be vulcanised at as high as 135°C. [Pg.261]

X-ray evidence shows the material to be completely amorphous as might be expected from such a complex mixture. The specific gravity ranges from 1.05 to 1.10. It is slightly harder than gypsum and therefore just not possible to scratch with a fingernail. Yellow in colour, it is less brittle than other hard natural resins and may therefore be carved or machined with little difficulty. The refractive index is 1.54. [Pg.871]

The carbonyl compounds [Fe(CO)5], [Mn2(CO)iol, and [Co2(CO)g] react in the same manner and no traces of a neutral or cationic carbodiphosphorane complex can be detected. In the case of these earlier and middle carbonyls in non-polar solvents, apparently the hard nature of C(PPh3)2 comes into force upon attacking a carbonyl carbon atom and formation of the C2PPh3 ligand [122] in THF, DME, quantitatively the related salts (HC PPh3 2)[M(CO)J (M = Mn, x = 5 M = Co, X = 4) were formed upon deprotonation of the solvent [123, 124],... [Pg.75]

Explosive Materials by Micro Hardness , Nature 181, 260-61 (1958) 71) V.V. Sviridov,... [Pg.93]

The mass to be ground in placed in a porcelain container with grinding spheres which in its turn is situated on top of two rotating axes. The grinding spheres come in different sizes and degrees of hardness. Naturally... [Pg.133]

The iron obtained by this process is known as pig or cast iron and contains about 4% carbon (as well as some other impurities). The name pig iron arises from the fact that if it is not subsequently converted into steel it is poured into moulds called pigs. Because of its brittle and hard nature, the iron produced by this process has limited use. Gas cylinders are sometimes made of cast iron, since they are unlikely to get deformed during their use. [Pg.170]

Except for the anomalous pyridyl group, the above values confirm the hard nature of lanthanides. [Pg.276]

S. C. Wallwork and T. T. Harding. Nature 171, 40-1 (1953). GrysAl structure phenoqUinone, quinhydrone, complexes. [Pg.444]

As opposed to that, hard natural water (with high content of Ca, Mg, Fe and other polyvalent metals) has low household properties. To decrease the hardness, such water is run through sea clays or shales... [Pg.175]

Enamels are characterized by their smooth and glossy appearance and hard nature. They are primarily pigmented varnishes or varnish-paint mixtures. [Pg.176]

Total hardness (natural hardness - - age hardening) of Pb—Sb alloys. Cast temperature 500 °C,... [Pg.159]

However, the affinity for metal cations is also regulated by the character of the donor atoms contained in the podand framework. " While the all-oxygen podands, in keeping with the hard nature of the oxygen donor atoms, favor the formation of complexes with alkali and alkaline earth metal cations incorporation of nitrogen and sulfur donor atoms into the podand framework is attractive, as it alters the binding tendency of all-oxygen podands so that they may more readily complex cations of the transition metals, such as Ag, Cd, Hg, Co, or Several other... [Pg.1111]

It must be concluded that this is another example of nucleophilic assistance. In this case even in protic environments the fluoride ion can serve as this agent, presumably because of the hard/hard nature of the interaction. We shall see that in the R—sn system, hydrogen-bonding solvents wash out such nucleophilic participation from the observed kinetics. [Pg.321]

The only exception seems to be the rock asphalt of Buton Island (south of Sulawesi Island) in Indonesia. In this island, the rock asphalt forms hills and mountains. This porous rock contains hard natural asphalt (penetration of 5-10 dmm) at 15%-30% and soft limestone with fossilised shell impurities. The extraction is very simple and cheap, because of low local labour cost thus, it is used locally for the production of bituminous mixtures. [Pg.98]

The next stage of development was to incorporate a resin into the bodied oil to further increase the viscosity, which was adjusted with a thinner, usually white spirit, to facilitate application. The resins used were initially the hard natural resins such as Congo copal, which required pyrolysis (running) to render them miscible with the oil. These were followed by synthetic phenolic resins. It was at this stage that unpigmented products (varnishes), particularly copal varnishes, were widely used. [Pg.244]


See other pages where Hardness nature is mentioned: [Pg.213]    [Pg.392]    [Pg.226]    [Pg.884]    [Pg.303]    [Pg.11]    [Pg.392]    [Pg.39]    [Pg.213]    [Pg.640]    [Pg.115]    [Pg.1194]    [Pg.122]    [Pg.569]    [Pg.69]    [Pg.74]    [Pg.105]    [Pg.105]    [Pg.14]    [Pg.195]    [Pg.607]    [Pg.1194]    [Pg.291]    [Pg.4648]    [Pg.48]    [Pg.136]    [Pg.40]    [Pg.130]    [Pg.541]    [Pg.31]    [Pg.26]   
See also in sourсe #XX -- [ Pg.7 , Pg.8 ]




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