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Effects of picking periods and average mass of seed on fibre properties of MCU-5 cotton
Abstract
The effects of picking periods and average mass of seed on fibre properties have been studied using MCU-5 Indian cotton variety, collected from three different locations at various picking periods. It is observed that there is a significant impact due to the average mass of seed in a particular picking period on fibre quality. In general, the mass of seed plays a vital role in deciding the quality of fibres.
The impact of mass of kapas and its fibre properties on fabric quality has been studied using four different carded yarn samples namely 'Below 100mg', '100-150mg', '151-200mg' and Normal sample of 50 s Ne for the production of handloom fabrics. All the fabric samples have been produced with uniform process parameters and their tested as per the standard procedure for durability, aesthetic characteristics, and colour fastness properties. It is observed that the mass of kapas and its fibre properties significantly affect the fabric quality.
An experimental study was carried out to obtain a clear understanding of quality of mixed fibers within the variety as well as in between the variety with reference to the mass of kapas, seed and locules. Locules or kapas of three different Indian varieties (Suvin, DCH32 and MCU-5) were collected and randomly grouped as to their mass with an interval of 5 mg. Mixing of fibers of different kapas was completed by utilizing equal quantity of fibers from each kapas group. It was found that mixing is essential even if the process involves only a single variety of cotton. Results indicate that the compactness of individual fiber group or volume occupied by the fibers under any known opening processes is a key consideration during the mixing of fibers of different groups.
Reduction in variation of fibre properties within particular fibre groups to get excellent fibre and yarn qualities from the available raw material and categorization of seed cotton prior to ginning with respect to their mass has been explored. For appropriate utilization of raw material to produce yarn of a particular quality, the manually picked seed cottons were grouped with respect to their mass measured with an accuracy of 0.001g. The grouped seed cottons were then ginned on roller gin with four different roller and beater speed combinations and fibres of each group were tested using AFIS and HVI as per the standard procedure. The yarn samples were produced as per the sequence of process used for carded cotton yarn. The separation of the seed cottons with respect to their mass results in the categorization of fibres with respect to their physical properties. The higher mass of seed cotton results in superior fibre properties and vice versa. Similar to fibre properties, a significant enhancement in yarn quality is also observed, particularly in the samples '101-150mg' and '151-200mg' for both 50s and 60s Ne count yarns.
50% Span length, uniformity ratio and bundle tenacity show a significant and consistent improvement from card to drawing sliver in carded mixing in HVI while no such trend is found in Baer sorter and Stelometer results. In combed mixing also, bundle tenacity by HVI increases from card to comber and from comber to drawing, while no such increase is found in Stelometer results. The crimp removal in drawing and the reduced short fibre content in the clamped beard contribute to the increase in tenacity from card to drawing sliver in HVI. HVI results do not agree well with that of Baer sorter in regard to incidence of fibre breakages in blowroom.
The picking periods and their combinations on fibre and yarn properties have been studied using MCU-5 variety of Indian cotton which was collected from four different locations at various picking periods. It is observed that the picking periods affect the fibre and yarn qualities. Better fibre and yarn can be achieved by excluding the fibres from the last few picking periods.
The effects of varieties, harvesting practices, and ginning techniques on the nep content of ginned lint were evaluated in a two year study in the Mississippi Delta. Neps increased more with lint cleaning during ginning than with harvesting practices or varieties. Two stages of lint cleaning increased the neps in ginned lint from 15.9 to 36.2 neps/645 cm2 of web. Differences caused by varieties were about equal to those caused by harvesting practices. The nep content was not significantly related to the number of seedcoat fragments, foreign matter, or grade.
The interactions between picking dates, locations, and varieties were studied to evaluate the effect of growth period on neps in ginned lint, yarn, and fabric. Five harvest intervals were selected, and the cotton yield increments between intervals were used to provide five levels of maturity. Neps in raw cotton were measured by the USDA-AMS web nep test and microscopic examination of card web, imperfections in the yarn ascertained by the Uster instrument, and neps in woven fabric counted by dyeing procedures. Results showed that growth period has a significant impact on the number of neps and other imperfections found in lint and manufactured yarns and fabrics. As a general rule, cotton grown early in the season will produce yarns and fabrics with a lower number of imperfections than cotton grown late in the season from the same field.
Three species of cotton grown in different areas of the United States (Mississippi, California, Texas) during 1982 are associated with differing levels of gram negative bacilli and endotoxin activity. Area of growth is an important variable in determining airborne levels of gram negative bacilli and endotoxin activity when the cotton is carded.