Second comparison: the second correlation to be verified was the one between Pressley and Stelometer fiber strength and that of Ne 38 yarns produced with all three blend. The confrontation was carried out among 52 tests and the results are reported in tab. 3 and 4 where it is noted that the correlation coefficient Pressley/Rkm is 0.96 and Stelometer/Rkm is 0.95. They are extremely significant data which allow calculating the two conversion formulas and suppose the yarn strength starting only from the strength of the fiber bundle, with great precision.

TAB. 3 | Ne 38 yarns | TAB. 4 | Ne 38 yarns | |||

Pressley average (X) | 93.25 | Stelometer average (X) | 22.40 | |||

L.R.km average (Y) | 16.09 | L.R.km average (Y) | 16.09 | |||

Correlation index | 0.96 | Correlation index | 0.95 | |||

Theoretical line | Y = -4.43+0.22*X | Theoretical line | Y = 4.44+0.52*X | |||

Example | ||||||

Pressley | L.R.Km. | Stelometer | L.R.Km. | |||

Ne 38 | Ne 38 | |||||

X | Y | X | Y | |||

80 | 13.17 | 19 | 14.32 | |||

85 | 14.27 | 20 | 14.84 | |||

90 | 15.37 | 21 | 15.36 | |||

95 | 16.47 | 22 | 15.88 | |||

100 | 17.57 | 23 | 16.40 | |||

105 | 18.67 | 24 | 16.92 | |||

Third comparison: the third correlation to be verified was the one between Pressley and Stelometer fiber strength and that of Ne 50 yarns produced with all three blends.

The comparison was carried out among 40 tests and the results are reported in tab. 5 and 6 where it can be noted that the correlation coefficient Pressley/Rkm is 0.89 and Stelometer/Rkm is 0.88. The explanation is the following: it is renowned that if a yarn is refined, the number of its weak points increases. This causes more dispersion of fiber strength values (and increase in its Variation Coefficient) and consequently lower correlation index between the strengths of fibers and yarn.

Supported by mathematical formulas and with high reliability rate, we can therefore state that it is possible to suppose the strength of a yarn starting from the fiber strength data.

TAB. 5 | Ne 50 yarn | TAB. 6 | Ne 50 yarn | ||

Pressley average (X) | 96.88 | Stelometer average (X) | 23.97 | ||

L.R.km average(Y) | 16.57 | L.R.km average (Y) | 16.57 | ||

Correlation index | 0.89 | Correlation index | 0.88 | ||

Theoretical line | Y = -4.74 + 0.22 * X | Theoretical line | Y = 2.67 + 0.58 X | ||

Example | |||||

Pressley | L.R.Km. | Stelometer | L.R.Km. | ||

Ne 50 | Ne 50 | ||||

X | Y | X | Y | ||

80 | 12.86 | 19 | 13.69 | ||

85 | 13.96 | 20 | 14.27 | ||

90 | 15.06 | 21 | 14.85 | ||

95 | 16.16 | 22 | 15.43 | ||

100 | 17.26 | 23 | 16.01 | ||

105 | 18.36 | 24 | 16.59 |