Mathematical Combination of Measured Fibre Diameter Distribution Histograms for Greasy and Scoured Wool

Abstract

IWTO-31-86(E) includes a formula for combining Mean Fibre Diameter for sublots where the mean diameter is measured using Airflow. IWTO-12-93(E) includes
formulae for combining Mean Fibre Diameter and Coefficient of Variation, where the diameter distribution data are also available.

The development and commercialisation of rapid techniques for measuring fibre diameter distributions for lots of greasy and scoured wool has generated increasing interest in obtaining these data for consignments of the same. While these data can be obtained by measuring a single sample drawn from the consignment, in practice it is more common for sublots that make up the consignment to be sampled and measured and the results of these individual tests combined, using the formulae in IWTO-12-93(E). However IWTO-12-93(E) does not provide a formula for producing a combined histogram from the individual sublot histograms and there is increasing demand for this to be also available.

Consequently a mathematical formula has been derived for estimating the fibre diameter distribution histogram for a blend of wool fibres, from the distribution histograms for each component of the blend. The derivation of this formula is described in this submission. The submission recommends that IWTO-12-93(E) be amended to include this formula and details a number of other, associated amendments. 

Citation

"Mathematical Combination of Measured Fibre Diameter Distribution Histograms for Greasy and Scoured Wool", P Semmel & P. J. Sommerville, Submission to IWTO Technical Committee Working Group: RAW WOOL GROUP, Nice - December 1995