Wool fibers are subjected to severe mechanical processing following scouring, which results in physical damage. This study investigates the role of physical processing in changing the physical and chemical properties of the fibers. Removal of surface-bound lipids following physical processing is minimal, but there are significant morphological changes related to an increase in the chemical susceptibility of the fibers to chemical attack. The finding is demonstrated by the more effective removal of bound lipids from fibers in the form of top than from aqueous scoured fibers.
The model described in Part I has been evaluated using as a starting point fiber strength and withdrawal-force parameters derived from tensile testing. These param eters were then adjusted to give an optimum fit of the theory to published data. The differences in the measured and the fitted values could probably be mainly ascribed to differences between the wool types measured and those used in the published data and to differences between the slow loading in testing and the more rapid loading that occurs in carding. With optimum adjusted values of the parameters, it was possible to get good agreement between the predicted and the actual fiber length distributions after carding, except for a tendency for the proportion of short fibers to be underestimated. This was no doubt due to the nonconformity of actual fibers to some of the assumptions made.
We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero.