Size Distributions

Abstract

All of the parameters that were described in the preceding chapter are ones that apply to the sample as a whole. They tell us about global averages but not about the way that the structure is organized. An example of a very important parameter that is often desired to describe structures in which there are dispersed features in a matrix is the number of such features per unit volume, N _V . But this is not something that we can directly determine. Consider the cases shown schematically in Figure 1. The sections are identical, and show the same number and size of intersections, but the number and size of the 3-D features is quite different. Even if we restrict ourselves to the case of convex features, the number of intersections on our test section will depend on the size distribution and volume fraction of the features, as well as on their number. It is necessary to consider all of these things together.