Artan Sinoimeri

A New Method of Measurement of the Inter-fiber Force

The friction and cohesion forces are some of the most important parameters that affect the yarn spinnability and tenacity. A new and simple device was carried out in order to quantify the friction and cohesion forces during a quasi-static fiber slippage in a sliver. This device was composed of two identical small carriages. One of them was fixed, whereas the second was moving on a linear guide. A piece of sliver was put down in the carriage channel in zero-gage position. The sliver was compressed with the upper carriage sides, where two identical weights were loaded. This apparatus was tested under different loads, sliver counts and speeds. The results were analyzed in order to check out the parameters which characterized the friction force during inter-fiber slippage.

Effects of Blending Parameters on the Cross-section Fiber Migration of Silk/Cotton Blends

Six types of 30 tex silk and cotton blended yarns at 50/50 blending ratio were spun in the cotton spinning system in order to study the effects of blending factors on the fiber distribution in the yarn cross-section. The blending factors studied here were the blending methods, intimate and drawframe blending, and the silk waste types, inferior knubbs, filature gum waste and pierced cocoon. A new method of zoning the yarn cross-section has been proposed in order to analyze the fiber migration. Three migration parameters, the Index of Blend Irregularity, the Migration Intensity and the Migration Index were studied in the present work. The intimate blending gave a more homogeneous fiber distribution, with no radial migration tendency. The coarser silk fibers and more irregular in length provided blends that presented non-random heterogeneity. Generally, the silk fibers slightly tended to migrate toward the yarn core.

Silk Waste/Cotton Blended Yarns in Cotton Microspinning: Physical Properties and Fibre Arrangement of Blended Yarn

The microspinning technology has generally been used for cotton in the case of small scale spinning test methods (50 gram fibres). One type of silk fibre waste -pierced cocoonprepared previously as short silk fibre with cut length of 35 mm is blended with cotton fibre to obtain further data concerning two blending techniques in this microspinning, and to compare pure and blended yarns. The intimate (before carding and drawframe blending as well as the roll settings in the drawing system are being examined. The silk content was changed at 0/100, 25/75 and 50/50 ratio for a yarn count of 30 tex. The physical properties, the irregularity and the fibre arrangement as terms of the Index of Blending Irregularity and the Migration Indices of the blended yarns have been studied. In addition, the effects of the blending techniques as well as those of the silk content have been brought to the fore.

New findings on within bale repeatability of measurements obtained with standardized instruments for testing cotton (SITC) in Gossypium Hirsutum Fiber produced in West and Central Africa

Around 50% of the cotton bales produced in the world are sold based on the analysis of their technological characteristics using a standardized instrument for testing cotton (SITC). In the United States of America, periodical studies of variability of the results allow the results to be accompanied by commercial tolerances to limit the frequency of claims. However, to our knowledge, no such study has been conducted in Africa. For this reason, we studied within-bale variability of fiber micronaire, length, uniformity, strength, reflectance and yellowness as measured by the SITC. We took eight samples per bale from 215 cotton bales produced by 27 ginning mills in eight Sub-Saharan countries in Africa in two cropping seasons. Our representative sample was composed of 1720 fiber samples that were analyzed in controlled conditions using the SITC in a laboratory in which international recommendations are fully respected. We measured within-bale variability and suggest a sampling method and procedure to perform technological and instrumental tests in West and Central Africa.

Application of a published methodology for evaluating within-bale repeatability of measurements obtained with standardized instruments for testing cotton: Gossypium hirsutum in Eastern and Southern Africa

The possible application of conclusions from a published study concerning cottons from West and Central Africa (WCA), involving an evaluation of the within-bale variability of fiber Micronaire, Length, Uniformity, Strength, Reflectance and Yellowness in cottons from Eastern and Southern Africa (ESA) was investigated. We took eight cotton samples per bale from 240 bales produced by 32 ginning mills in six ESA countries in two crop seasons. Our representative sample comprised 1920 fiber samples that were centrally analyzed under controlled conditions using standardized instruments for testing cotton (SITC). We evaluated within-bale variability levels for both saw- and roller-ginned cottons and checked the applicability of the published conclusions to ESA. We found that (1) sampling variance levels were comparable in ESA and in WCA for saw-ginned cottons, (2) WCA recommendations for saw-ginned cottons would also apply in ESA for most fiber characteristics measured by SITC, and (3) for roller-ginned cottons, the higher within-bale variability of roller-ginned cotton fibers compared to saw-ginned cotton would require the definition of a specific sampling and testing method based on an experiment to be designed.

Inter Fiber Frictional Model

One of the effective forces in the textile process is friction. A new and simple device is developed in order to quantify the friction forces during a quasi-static fibre slippage in sliver. The device is composed of two identical clamps, one of which is fixed and the other moving through a linear guide. A piece of sliver was maintained under controlled pressure in the zero gage position of the two clamps. The frictional force during the fibre slippage in the sliver was measured using three different speeds, eight different normal loads and three different sliver counts. Five replications were preceded for each factorial combination. In general, the frictional force increased with the speed, but the analysis of variance of the data indicated that the effect was not significant, whereas the effect of the normal load on frictional force was positive and highly significant. A statistic model based on these results is proposed with respect to sliver count and normal load. Following this model, the effects of the normal load and sliver count on the frictional force were not linear.