Inactive Blacks

The N 300 series is characterized by a wide variety of rubber blacks, covering about 10 different types. As mentioned above, fme-particle active blacks are used for rubber components that need to withstand significant levels of mechanical stress, e.g. tire treads. Semi-active blacks, on the other hand, are used in the tire carcass but also in technical rubber components, from screen and door seals to floor mats. Tires also contain other special carbon blacks, for instance, so-called adhesion blacks for improving radial steel belt adhesion, conductive blacks or inactive blacks for higher filler load rates [4.26]. 

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Bismuth Triiodlde. Bismuth(Ill) iodide is a greenish black crystalline powder. The iodines are in a hexagonal close-packed array with each bismuth having six nearest-neighbor iodines at 0.32 nm (21). This suggests that the lone pair on bismuth is stereochemicaHy inactive and that the compound is largely ionic in character. 

Figure 4 Excluded volume for the Di agonist pharmacophore. The mesh volume shown by the black lines is a cross section of the excluded volume representing the receptor binding pocket. Dihydrexidine (see text) is shown in the receptor pocket. The gray mesh represents the receptor essential volume of inactive analogs. The hydroxyl binding, amine binding, and accessory regions are labeled, as is the steric occlusion region.

The presence of red ferric oxide usually indicates an inactive pit but black oxide infers active pitting. Condensate receivers are common points for oxygen infiltration (especially in smaller boiler plants). 

The ligandless Beletskaya catalysts, PdCl2(CH3CN)2 used in DMF or acetone with tin-substituted alkynes and sp -hybridized iodides and bromides. This system is very reactive and relatively cheap. The disadvantage is that it decomposes quickly under development of catalyticaUy inactive Pd-black particles [20 c]. 

Carbon blacks are principally made by the chemical decomposition of natural gas or oil. Two classes predominate the furnace blacks (95% of black usage) which are active, and thermal blacks (5% of usage) which are inactive. There are a substantial number of blacks for special applications such as electrically conducting and printing ink blacks. The latter are of too fine a particle size for rubber use. The nomenclature used for carbon blacks includes the ASTM designation and the industry type as illustrated in the next table. 

Addition of pvp significantly extends catalyst lifetime (Scheme 2). This is a well-known protocol whereby the Pd nanoparticles are wrapped up in the polymer chains, which prevents their aggregation into catalytically inactive palladium black. 

The most commercially successful reactive dye of all, Cl Reactive Black 5 (7.36) contains two sulpha toe thylsulphone precursor groups that contribute markedly to its initial solubility. When these are hydrolysed in alkali to release the reactive bis(vinylsulphone) form, the considerable increase in substantivity (Table 7.3) leads to highly efficient fixation. Further hydrolysis of the vinylsulphone groups to give the inactive bis(hydroxyethylsulphone) derivative, however, lowers the substantivity and hence contributes to favourable wash-off performance. 

The inactive, arrested caries lesion is black, remineralized, and hard on probing, whereas the active lesion is brownish and soft. Increased oral... 

Fig. 6. Typical butyrin test for lipase activity in which the agar plate is placed on a black background for visualization. White dots represent bacterial colonies those having no (even) black background contain inactive mutants (66d).

Copper based catalysts have long been considered as the only effective methanol synthesis catalysts. However, Poutsma et al. (7) showed that palladium catalysts were active in methanol synthesis from CO-H. This latter metal had been previously considered as either almost inactive or active only for methane formation (8). Furthermore it is now known that both activity and selectivity can change drastically with the support. Vannice (9) observed that the methanation activity of a Pd/Al O was enhanced eighty and forty times compared to palladium black or Pd/SiO (or Pd/TiO ) respectively. The support effect on the selectivity was pointed out by many authors even at atmospheric pressure when the reaction temperature... 

FIGURE 12-7 Activation of the insulin-receptor Tyr kinase by autophosphorylation. (a) In the inactive form of the Tyr kinase domain (PDB ID 11RK), the activation loop (blue) sits in the active site, and none of the critical Tyr residues (black and red ball-and-stick structures) are phosphorylated. This conformation is stabilized by hydrogen bonding between Tyr1162 and Asp"32, (b) When insulin binds to the a chains of insulin receptors, the Tyr kinase of each /3 subunit of the dimer phosphorylates three Tyr residues (Tyr"58, Tyr"62, and... 

Dichlorophenpxy) acetic acid-14C is metabolized by plant tissue to inactive, water-soluble substances, some of which regenerate the parent acid on hydrolysis. The rate of metabolism differs with different species, but is usually low in comparison with the indole or naphthalene auxins. One of the earlier studies described a single major metabolite in corn, wheat, peas, and tomatoes,121 the identity of which is still uncertain. In another study of differences between species which were susceptible and those which were resistant to the herbicide, the resistant red currant metabolized 50% of the carboxyl-labeled and 20% of the methylene-labeled (2,4 dichlorophenoxy)acetic acid to 14COi in seven days, whereas the susceptible black currant altered122 only 2%. Similar effects were found with apple varieties. Strawberry and lilac decarboxylated the herbicide readily however, 16 other species, of various susceptibilities to herbicide, were unable to decarboxylate the acid to any significant extent. In both varieties of currant, 5 to 10% of the herbicide was converted into water-soluble derivatives of the parent acid, and 10 to 30% was bound in the leaf tissue in an unextractable form. 

Ball-and-chain model for inactivation of the K+ channel, (a) Open conformation, (b) inactive conformation. (From Research News, Science 250 507, 1990. Reprinted by permission of Suzanne Black.)... 

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