We have seen that the propensity of cotton fibres to incur thin and thick places during drafting can be quantified in terms of two critical lengths. Fibres longer than the first critical length are very unlikely to incur irregular movement; fibres shorter than the second the critical length are most likely to incur irregular movement. We have to identify these two critical lengths |
For this we selected 12 cottons to represent the widely different types of length distribution encountered in Indian commercial cottons – Table II – A – 2 - i. We spun each of the 12 cottons to NE 22, 30, and 40. Then we correlated the Uster counts of thin and thick places of the yarns with the fibre-length characteristics of the cotton used to spin the yarns Thereby we identified the critical fibre lengths to be 12-mm and 24-mm. |
The set of regression equations that we obtained in this exercise contains three independent variables: Q, a derivative of effective length and the percentages of fibres shorter than 12-mm and longer than 24-mm.; H, the fibre fineness; and yarn count. |
The final set of equations could be written in terms of the following fibre characteristics: L, the Baer sorter effective length in mm; S, the percentage fibres by number shorter than 12 mm; B the percentage fibres longer than 24 mm; H, the fineness in millitex. |
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Table II – A – 2 – I Length frequency distribution of cottons used in investigation to identify critical fibre lengths that characterize cottons for their propensity to incur thin and thick places in yar |
CLASS
LENGTH
IN mm. |
% FREQUECY IN CLASS |
CO-2 |
J-34K |
Som |
CJ |
J-34 |
F-414 |
JYOTI |
MCU-7 |
S-4 |
MCU-5 |
VL |
DCH-32 |
2 |
1.9 |
2.5 |
1.8 |
2.4 |
2.1 |
3.0 |
1.6 |
2.2 |
2.8 |
2.8 |
2.6 |
1.6 |
6 |
15.7 |
11.7 |
10.4 |
11.5 |
9.1 |
8.0 |
9.7 |
11.6 |
8.5 |
11.2 |
11.0 |
11.7 |
10 |
12.7 |
11.8 |
9.8 |
10.8 |
10.9 |
8.7 |
12.1 |
10.8 |
8.6 |
15.0 |
9.2 |
13.3 |
14 |
13.7 |
11.4 |
9.8 |
11.9 |
9.1 |
10.0 |
10.3 |
7.2 |
7.0 |
9.3 |
8.1 |
9.2 |
18 |
16.1 |
14.4 |
12.2 |
15.1 |
13.9 |
11.5 |
11.6 |
7.8 |
7.0 |
8.9 |
7.7 |
7.1 |
22 |
23.1 |
20.4 |
20.4 |
18.1 |
19.6 |
19.6 |
17.7 |
11.4 |
9.7 |
9.8 |
9.0 |
7.1 |
26 |
11.8 |
19.9 |
23.8 |
16.7 |
22.3 |
23.6 |
18.7 |
20.4 |
15.9 |
10.8 |
11.2 |
8.3 |
30 |
5.0 |
6.8 |
8.7 |
10.0 |
8.5 |
11.3 |
12.0 |
17.7 |
18.2 |
10.3 |
17.0 |
8.7 |
34 |
0.0 |
1.1 |
3.1 |
3.3 |
4.2 |
3.9 |
6.3 |
7.1 |
14.3 |
10.3 |
13.8 |
8.8 |
38 |
0.0 |
0.0 |
0.0 |
0.2 |
0.3 |
0.4 |
0.6 |
3.8 |
6.9 |
8.1 |
7.8 |
10.7 |
42 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
1.1 |
3.5 |
2.3 |
8.1 |
46 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.3 |
4.9 |
50 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.5 |
70 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
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