![]() | يوجد فقط 14 صفحة متاحة للعرض العام |
المستخلص 1. INTRODUCTION The price of cotton crop and the monetary return to the cotton grower depend on fiber yield and quality, both of which are set by crop management practices in interaction with the growth environment. Fiber yield is easily quantified in bales or kantar per feddan, but fiber quality is a complex of both qualitative and quantitative properties like fiber length, length uniformity, fineness, maturity, strength, color, and trash content. Measurement of fiber quality is further complicated by significant natural and environmental variations in fiber shape and maturity at the bale, plant, boll, and seed level. The best utilization of raw material for manufacturing the optimum quality of yarn has become inevitable for the spinning mills to face the global competition. Yarn strength, evenness and hairiness are the most important parameters from quality point of view and largely depend upon the fiber length and micronaire value, which are considered the foremost quality parameters for the selection of raw material. The cotton fiber is a single cell formed by the elongation of an epidermal cell on the surface of the seed. The cotton fiber chronological maturity is estimated by the days after anthesis, but classification and processing qualities depend on physical maturity, which refers to the degree of development or thickening of the cell wall relative to the perimeter or effective diameter of the fiber. The degree of thickening (θ), defined as the ratio of the wall area to the area of a perfect circle having the same perimeter, is considered the best parameter indicating fiber maturity (the degree of development of the fiber wall). Since the gravimetric fineness or linear density of the fiber is directly proportional to the wall area and the genetic fineness or perimeter, the cross-sectional fiber measurement fully describes both cotton fiber maturity and fineness. The problem of correctly assessing the maturity of a sample of cotton remains a serious issue for the world textile industry. The presence of immature cotton in a laydown poses significant problems in processing performance and in the quality of the finished textile. These problems may include: neps, weak places in yarns, ends-down in spinning, excess waste, and dyeing imperfections such as white specks and barré. Though, maturity is the most important and interesting quality characteristics of cotton fibers that still challenges and fascinate all workers with cotton, from the growers to the finishers and the scientists. The present marketing system does not include a direct measure of maturity. Direct micrometric and gravimetric measurements of this trait are tedious, time consuming and are not suitable for the quick routine tests. The most widespread cotton fiber tester is the Micronaire, which measures a combination of fiber fineness and maturity. Having a well established average perimeter (as the intrinsic fiber fineness) for the commercial cotton varieties, practical unbiased determinations of maturity parameters could be attained from the rapid simple micronaire test. The present were investigates explores the possibility of utilizing micronaire reading to obtain quick unbiased cotton fiber maturity parameters. Such as the degree of wall thickening (θ), percent of maturity (PM), maturity ratio (M) or the hair weight (H.W). Besides, clarifying the relationship between the attained parameters. |