Team approach, multi-functional


For high temperatures one would naively expect that r/7 is near to 1, and then for lower temperatures slowly starts to deviate from equihbrium, meaning that this ratio should decay. However, as Fig. 12 shows, for high temperatures this ratio is significantly smaller than 1, increasing with decreasing temperature and then breaking down to approach 0. The deviation at high temperatures comes from the fact that the simple definition of Eq. 4 takes into account only uncorrelated intra-chain effects. However, when one simulates a melt of chains the degeneracy of the states is significantly different, due to the constraints on a given monomer induced by all the other monomers. If one corrects for this, one actually finds that for high temperatures this ratio is very near to 1 and slowly decays as a function of temperature until it starts to break down around the glass transition temperature. However, the general scaling picture as shown in Fig. 12 does not change significantly up to a shift. Since all the data for the different cooling rates more or less coincide and define a characteristic temperature where the curve changes its behavior, this figure suggests that there might be a possi-bihty of defining a universal glass transition temperature for the cooling rate going to 0. This procedure actually allows one to compare the cooling rate dependent glass transition temperature with the asymptotic freezing temperature of a system. Certainly, there has to be much more research in this  [c.503]

The strucmres of the first group of glasses are consistent with the suggestion that tire smaller metalloid atoms fill holes in tire metal strucmre, and enable a closer approach of tire metal atoms and an increased density. The atTangement of the metal atoms can either be in a random network or in the dense random packing model of Bernal, in which the co-ordination number of the metalloid can be 4, 6, 8, 9 and 10, some of tire latter tlrree involving 5 co-ordination of the non-metal. The formation of glass requires tlrat the rate of cooling from the melt must be greater than the rate at which nucleation and growth of a crystalline phase can occur. The minimum rate of cooling to attain the glass structure cair be obtained for airy system by dre observation of dre rate of crystallization as a function of supercooling below the liquidus. The extremum of dre TTN (time, teirrperamre, nucleation rate) curve shows dre maximum rate of nucleus formation as a function of undercooling temperature, and hence dre minimum in dre rate of cooling required to achieve dre formation of a glass.  [c.298]

In modern practice, inhibitors are rarely used in the form of single compounds — particularly in near-neutral solutions. It is much more usual for formulations made up from two, three or more inhibitors to be employed. Three factors are responsible for this approach. Firstly, because individual inhibitors are effective with only a limited number of metals the protection of multi-metal systems requires the presence of more than one inhibitor. (Toxicity and pollution considerations frequently prevent the use of chromates as universal inhibitors.) Secondly, because of the separate advantages possessed by inhibitors of the anodic and cathodic types it is sometimes of benefit to use a formulation composed of examples from each type. This procedure often results in improved protection above that given by either type alone and makes it possible to use lower inhibitor concentrations. The third factor relates to the use of halide ions to improve the action of organic inhibitors in acid solutions. The halides are not, strictly speaking, acting as inhibitors in this sense, and their function is to assist in the adsorption of the inhibitor on to the metal surface. The second and third of these methods are often referred to as synergised treatments.  [c.780]


See pages that mention the term Team approach, multi-functional : [c.555]   
Designing capable and reliable products (2000) -- [ c.269 ]