Carbon soft", definition

Polyethylene terephthalate) (PET), with an oxygen permeability of 8 iiiuol/(ius-GPa), is not considered a barrier polymer by die old definition however, it is an adequate barrier polymer for holding carbon dioxide in a 2-L bottle for carbonated soft drinks. The solubility coefficients for carbon dioxide are much larger than for oxygen. For the case of the PET soft drink bottle, the principal mechanism for loss of carbon dioxide is by sorption in the bottle walls as 500 kPa (5 atm) of carbon dioxide equilibrates with the polymer. For an average wall thickness of 370 pm (14.5 mil) and a permeabdity of 40 nmol/(m-s-GPa), many months are required to lose enough carbon dioxide (15% of initial) to be objectionable. 

The presence of carbon in solid solution stabilizes the y iron structure and inhibits the transition to a iron. On slow cooling, therefore, austenite remains stable below the normal transition temperature of 910 °C, and it is only at about 700 °C that the solid solution breaks down and transforms into a mixture of ferrite and cementite. Ferrite is an interstitial solution of carbon in a iron, but the amount of carbon which can be taken up in solution is very small and is limited to about 0 3 atomic per cent. The excess of carbon is therefore thrown out of solution and appears in the definite compound cementite, Fe3C, with a complex orthorhombic structure. The solid is no longer homogeneous, and the characteristic appearance, due to the separation of ferrite and cementite, gives rise to the name pearlite. In this condition the steel is very soft. 

The term mineral black is applied to several materials. Field (1835) describes mineral black as a native impure oxide of carbon, of a soft texture, found in Devonshire . This definition is probably synonymous with Bideford black (. v.), since Field also states that his sample came from the Union mine, Bideford. 

Aside this confusion, there is a principal argument, not to use Evans convention, because the hard descriptors E andZ must not be redefined. The soft descriptors cis and trans, however, can be used without violation of the strict definitions of the unequivocal E and Z. Therefore, in this book, the recommendation of Eliel etal. [18] is followed using the soft descriptors cis and raKS, if a series or a class of enolates are addressed [19]. Thereby, cis means that the OM substituent is on the same side as the higher-priority group at the a-carbon atom, and trans means that the OM substituent is on the opposite side. Only in those cases, where an individual enolate is concerned, EtZ nomenclature is used according to its strict definition. 

When dealing with failure or stabilization of carbon electrodes, we can distinguish between factors that relate directly to surface reactions and those that relate to the nature of the Li insertion mechanism into the carbon. However, it should be noted that the factors related to the surface phenomena are also definitely connected to the 3D structure of the carbons. As already mentioned, Li insertion into either soft or hard disordered carbons, and the failure or stability of hthiated disordered carbon electrodes are much less dependent on their surface chemistry as compared with graphitic materials. This is due to the fact that graphites are much softer and weaker than disordered carbons. Hence, failure and stability of disordered carbon electrodes are mostly determined by structural factors, the type of Li insertion sites available, the number of C-H bonds, and the existence of sites to which Li is inserted irreversibly [81-85,94,95,97-99]. Discussion of these structural impacts on the behavior of the electrodes is beyond the scope of this chapter. 

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