Significant figures, effects principles

The principle significance of specific speed for the process engineer is to evaluate the expected performance of a second pump in a particular manufacturer s series while basing it on the known performance (or curve) at the point of optimum efficiency of a first and different size pump. In effect the performance of any impeller of a manufacturer s homologous series can be estimated from the known performance of any other impeller in the series, at the point of optimum efficiency. Figures 3-48 and 3-49 represent the standardized conditions of essentially all pump manufacturers. 

Figure 20.31 The principle of interconversion cycles in regulation of protein activity or changes in protein concentration as exemplified by translation/proteolysis or protein kinase/protein phosphatase. They result in very marked relative changes in regulator concentration or enzyme activity. The significance of the relative changes (or sensitivity in regulation) is discussed in Chapter 3. The principle of regulation by covalent modihcation is also described in Chapter 3. The modifications in cyclin concentration are achieved via translation and proteolysis, which, in effect, is an interconversion cycle. For the enzyme, they are achieved via phosphorylation and dephosphorylation reactions. In both cases, the relative change in concentration/activity by the covalent modification is enormous. This ensures, for example, that a sufficient increase in cyclin can occur so that an inactive cell cycle kinase can be converted to an active cell cycle kinase, or that a cell cycle kinase can be completely inactivated. Appreciation of the common principles in biochemistry helps in the understanding of what otherwise can appear to be complex phenomena.

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