ABSTRACT
In previous work on textile processing, a generalized "black-box" model of a fiber mechanical-handling process was presented, in which fiber breakage is characterized through the measurement and comparison of the length properties of input (raw) fiber and output (processed) fiber (1,2). It was shown that theoretical techniques can relate the observed differences in length distribution to the fundamental nature of the breakage mechanism inherent in the process (3). In the present work, a technique was developed for determining the fraction of short fibers in bale cotton from the relative shape of the distribution of longer fibers. The method assumes that any given cotton originates from a relatively mono-disperse length distribution (called a paragon), with accumulated degradation due to breakage like processes during production. Within broad classes, the paragon distribution is the same; so accumulation of different levels of short fiber is the result of varying degrees of damage inflicted. The degree of damage can be deduced by assuming a standard shape for the paragon distribution and comparing to it the shape of the (observable part of the) distribution of longer fiber in the bale sample. This generalized model was applied to Suter-Webb Array data for 207 upland cotton samples from the AMS 1989-crop Cotton Fiber and Processing Survey. The weight fraction of short fibers (less than 0.5 inch) was calculated from the shape of the length distribution of fibers longer than 0.5 inch. It was found that with a single paragon function, the correlation was R2 = 0.81. Taking the variation of paragon shape into account for different cottons should lead to further improvement in predictability. Progress in this approach is discussed.
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