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The aim of this study is to investigate the effect of spinneret design parameters on cross-sectional shape and mechanical performance characteristics of coaxial composite filaments. A number of different cross-sectional-shaped metal/polymer core/sheath coaxial composite filaments were developed by changing spinneret design parameters. The cross-sectional shapes obtained were circular, rectangular, triangular and elliptical shapes. The mechanical performance of filaments was evaluated for application in sensors and actuators. The change of cross-sectional shape significantly influences mechanical properties of developed filaments which express their vulnerability during applied stresses in their life cycle. [ABSTRACT FROM AUTHOR]

Selection of navel rotor spinning machine, which influences various quality parameters of the final yarn, is a multi-criteria decision-making (MCDM) problem. Different statistical methods have been used in the past to address such kinds of problems. In this work, a suitable navel for denim fabrics was selected by combining two popular MCDM approaches namely, technique for order preference by similarity to ideal solutions (TOPSIS) and analytic hierarchy process (AHP). Ten navels were considered and their performances were evaluated on the basis of seven quality parameters of the produced rotor yarns (50 tex). Relative importance of the yarn quality parameters was evaluated by using AHP method, keeping in mind the requirements of denim fabric. The final ranking of navels was elicited in accordance with the relative closeness value determined by TOPSIS method. [ABSTRACT FROM AUTHOR]

Modern high-speed spinning machines are equipped with automated inspection and monitoring systems that generate large quantities of data, necessitating special methods for their analysis. A hybrid system, based on a stochastic model and wavelet analysis was developed and applied to a large data set (500 MB) of yam diameters. Using a wavelet-stochastic hybrid approach, the data set could be reduced to a small fraction of its original size consisting of a set of statistical parameters for normal sub-blocks, a set of statistical parameters for abnormal sub-blocks for characterizing yam and fabric defects and for providing their spatial information, and a set of wavelet coefficients for abnormal sub-blocks. The compression ratio was approximately 100 000:1 in the example given. [ABSTRACT FROM AUTHOR]

This paper gives a theoretical analysis of the dynamics of deposition in the disc-spinning process and discusses the effect of the deposition action on fibre-straightening for improved fibre extent and alignment in disc-spun yarns. The idea of a fibre configuration being represented by one or more imaginary line(s) joining its leading and trailing ends is discussed. For the simplest case, two equations are derived that estimate the degree of straightening of a fibre during deposition and its alignment (i.e. parallelism) with the yarn axis. The theoretical calculations show that, when the leading end of a fibre first touches the surface of the forming yarn, and the position of the imaginary fibre line coincides with the direction of the velocity of the fibre's trailing end, then the fibre will be deposited with a very low extent and degree of parallelism. The greater the difference between the imaginary fibre-line position and the direction of the velocity of the trailing end, the straighter and more aligned with the yarn axis the fibre should he on deposition. [ABSTRACT FROM AUTHOR]