8—The Determination of Contacts between the Constituents of Fibre Assemblies

A radioactive tracer technique has been used to determine the number of fibre-to-fibre contacts in twistless slivers ranging in densities from 1-ε = 0.03 to 0.19. Fibres thinly coated with radioactive gelatin were processed to form a natural part of a sliver. As the gelatin was solidified at this stage, there was no transference of activity to other fibres, but, on warming in a moist atmosphere, the gelatin softened and activity was transferred at the points of contact with the surrounding fibres. After drying out the sliver, these points of transference were detected by means of autoradiographs. Over the range stated, the empirical relation n = 4.3 Χ 103(1-ε)3/2 has been found to express satisfactorily the number of contacts on one fibre per centimetre of sliver. The number of surrounding fibres contributing to these contacts has been obtained and found to increase linearly with density over the range, indicating that at low densities new contacts are formed mainly by previously independent fibres, whilst at higher densities most contacts are formed by the deformation of fibres which have already contributed some contacts.