Yaa Merits Too Limitations Of Cotton Fiber Fiber Length Mensuration Instruments (Part-2)

Merits together with Limitations of Cotton Fiber Length Measuring Instruments (Part-2)

N.Balasubramanian
Retd Jt. Director (BTRA) together with Consultant
I, Rajeswari, 36, 17th Road, Chembur, Bombay 400071, 9869716298
Email: balajamuna@gmail.com

Previous Part

Short Fibre Content (SFC)
SFC is indicated inwards two unlike ways. 1.% of fibres lower than a certainly length (usually 0.5 inch) 2.% of fibres less than Effective length from Baer sorter.

Balls sorter, Baer Sorter, together with Suter spider web sorter hand the virtually accurate gauge of SFC though they are fourth dimension consuming. Digital Fibrograph together with HVI, though rapid, hand unreliable estimate. From fibrograph, baer sorter bend tin live obtained past times differential method together with SFC tin live obtained.

Table two gives bridge lengths together with UI of fibrogrpah determined past times double plus method from master copy frequency distribution alongside three cottons of nearly same hateful length but differing inwards brusque fibre content (SFC %). UI is nearly the same for the three samples though SFC % is markedly different. This is because both 2.5 % together with fifty % bridge lengths are reduced inwards the same proportion alongside increment inwards SFC %. This amply demonstrates that UI past times fibrograph cannot hand whatever indication of brusque fibre content.

Table two : Comparison of 50%, 2.5 % bridge length together with UI alongside brusque fibre content %

Mean fibre length,mm	26.8	25.6	25.2
CV %	28.9	30.6	32.8
SFC %	7.3	12	14
50 % Span length, mm	16.6	13.6	14
2.5 % Span length	36.6	29.8	29.7
UI %	45.5	45.6	45.6

Cai12 et al constitute that the sampling inwards the beard of HVI is non very length biased. Except inwards brusque fibre part the sample is like to that of master copy sample. SFC past times HVI is lower than of master copy because of sampling. Chu together with Riley13 equally good constitute that the sample inwards the comb prepared past times fibre sampler is non a length biased sample. Each fibre irrespective of its length has equal probability of beingness caught past times the comb As a result, hateful length together with length distribution of fibres inwards the fibrosampler are to a greater extent than or less hateful length together with length distribution inwards the master copy sample. This seems to request that fibres are picked past times the sampler inwards clumps rather than individually. Some back upward to this contestation is constitute inwards the results of Carpenter10. Actual Fibrogram together with that derived from comb sorter results accept been compared past times Carpenter ( Fig 2). Actual fibrogram deviates from that derived from comb sorter, alongside difference increasing alongside length. As a final result fibre length together with brusque fibre content are nether estimated.

Fig two : Actual fbgrogram together with that derived from Comb sorter

HVI Testing
High book Instruments (HVI) accept speeded upward testing of fibre length apart from other properties substantially. Bale wise testing of cottons is possible together with bales alongside substandard characteristics tin live weeded out. HVI determines length characteristics based on Digital Fibrograph principle. ASTM, Standard D 5867-05 specifies the Standard Test Method for Measurement of Physical Properties of Cotton Fibers past times High Volume Instruments. Calibration cottons past times USDA are used to calibrate the instrument.

Limitations

1. Fibre breakages come about during comb training on HVI equally this is done at high speed. Such breakages are to a greater extent than alongside harsh, entangled cottons.

2. Further some length of fibre is used inwards clamping on the comb equally inwards Fibrograph leading to lower estimates of fibre length.

3. Breakages are equally good higher alongside carte du jour sliver compared to comber sliver. Over estimation of fibre fractionation is hence constitute inwards HVI.

4. As mentioned earlier,Cai12 et al together with Chu together with Riley13 even so constitute that the sampling used inwards HVI is non length biased but follows master copy distribution. This is supported past times the travel of Cui14 et al. The authors constitute a closed understanding betwixt frequency length distribution of cotton fiber of master copy sample together with that of fibres picked past times the clamp inwards fibrosampler. If fibrosampler sample is length biased equally assumed past times Hertel, together with so it should concord alongside length biased hateful obtained from the hateful together with CV of master copy sample. In Table three below hateful length of master copy together with Fibrosampler picked sample together with length biased hateful calculated from hateful together with CV of master copy sample from the information given past times Cui14 et al are given

Table three : Comparison of hateful fibre length of fibrosampler picked sample alongside master copy sample

Sample identification No	Mean fiber length of master copy sample, cm	Mean fiber length of Fibro sampler picked sample, cm	Length biased hateful fiber length calculated from master copy sample, cm
30	1.666	1.740	2.42
31	1.754	1.782	2.542
33	1.873	1.937	2.266
34	2.041	2.071	2.399
35	2.058	1.999	2.419
36	2.145	2.151	2.553
37	2.176	2.255	2.597
38	2.284	2.324	2.710

Table three shows that spell hateful fibre length of master copy together with fibrosampler picked samples are to a greater extent than or less each other, length biased hateful estimated from master copy sample is much higher inwards all the cases. This would hateful that fibrosampler picked sample is non length biased equally assumed past times Hertel.

Another interesting finding is that projecting share from the clamp has a higher fibre length than that hidden behind the clamp. Further twice the hateful length from projected sample is much higher than hateful length of fibrosampler picked sample. It appears that these anomalies accept arisen either because of the method followed inwards collecting projected share together with hidden share from the clamp or because fibres perish dragged frontward spell beingness picked inwards the comb.

To observe out the number of fibre length variability on differences caused inwards probability of fibre picking inwards fibrosampler, fibrograms prepared assuming equal probability for fibres is compared against that alongside length biased probability inwards fibrosampler are compared for cottons alongside depression together with high fibre length variability inwards Figs three together with four .

Fig three : Comparison of fibrograms alongside equal probability for fibres together with length biased probability inwards fibrosampler beard of high variability cotton, Mean length 26.8 mm, CV = 28.9 %

Fig four : Comparison of fibrograms alongside equal probability for fibres together with length biased probability inwards fibrosampler beard of depression variability cotton, Mean length 26.8 mm, CV = 14.5 % %

Table four shows that Fibrogram bridge length alongside equal probability for fibres is shorter inwards all length regions than that alongside length biased probability for fibres inwards fibrosampler beard. The difference is to a greater extent than pronounced inwards cotton fiber alongside high length variability especially inwards fifty % bridge length. 2.5% together with fifty % bridge lengths together with Uniformity Index are lower alongside equal probability than length biased probability. This agency that fibrograph estimates are lower than actual because fibrosampler does non alternative longer fibres alongside higher probability equally expected past times theory past times Hertel.

Table four : Comparison of bridge lengths alongside equal probability for fibres together with length biased probability inwards fibrosampler beards

(Click on picture for large size)

Projecting fibre sample
Belmasrour38 et al proposed a method for estimating fibre length distribution of a sample from length distribution of fibres projecting from the comb of fibrograph. Predicted bend gives practiced understanding alongside experimental except inwards brusque fibre region. CV of fibre length for the projecting fibre sample (from the fibrograph comb) was calculated for constant staple length, depression together with high length variability master copy samples are given inwards Table 5. CV of fibre length is equally high equally 57.7 % for cutting staple together with increases marginally to lx % inwards depression variability sample together with to 66% inwards high variability sample. High variability inwards beard sample is because of random clamping of fibre which is akin to random breakage of fibre. Variability of fibre length inwards master copy sample has alone a marginal number on variability inwards beard sample. Beard sample alongside length biased picking has a lower variability than equal probability picking.

Table five : CV of fibre length for the projecting fibre sample (from the fibrograph comb) for constant staple length, depression together with high length variability master copy samples