The irregularity of the results is decidedly less for the ballistic test than for the lea test but much greater for both than for the single-thread test when due allowance is made for the difference in the numbers of threads tested; the greater regularity of the results obtained by the ballistic test is somewhat discounted by the fact that they are much more affected by changes of humidity. [...] The second objection to the test is the difficulty of interpreting the results when obtained; although the lea test is commonly regarded as a strength test pure and simple the results of which provide a measure of the quality of the yarn yet they also depend upon the extensibility and the surface friction of the yarn. [...] The leas of the former were placed in the ballistic tester and the ends left free to move round the crossbars just as in the lea test; but the leas of the 1928-3o cottons were placed in the tester with a hitch knot A."8 A Study of Comparative Results for Lea Single Thread and Ballistic at each crossbar so as to prevent any such motion of the threads; with free ends not all the x6o threads break [...] The results for the different counts in the 20-4o's group are not what would be expected by analogy of low and very low counts for the extension of 4o's counts is lower on the average than that of the 3o's and of the 3o's than that of the 2o's the actual mean values being o84 for 2o's o74 for 3o's and o69 for 4o's; yet the values of the strength-ratios for 2o's 3o's and 4o's counts are 052 [...] Moreover once the yarn has passed through the various stages of preparation and becomes part of the finished doth the yarn extension becomes of less importance because it is only partially responsible for the extension of the fabric and there is no evidence to show that the total extesion of the yarn is one of the fundamental factors governing the utility of the fabric.
- Pages
- 35
- Published in
- India
- SARF Document ID
- sarf.143458
