Changes of colour and pH in fish musculature after ionizing radiation exposure

Irradiation of meat causes sensory changes as do other technological methods. The most significant sensory and quality indicator of meat is colour; therefore, the effect of irradiated pieces of fish was studied in relation to colour changes. Colour was measured at the musculature of Oncorhynchus mykiss. The parameters of colour, L*, a* and b*, were determined with the portable Superchroma S-Spex (Braive) spectrophotometer in the CIELAB system before irradiation (3 h post mortem) and after irradiation (⁶⁰Co source, a dose of 3 kGy and a dose rate of 3.33 kGy h^–1) (5 h post mortem). The change of L* was identical for both irradiated and nonirradiated samples. This change may be caused by maturation of fish flesh. a* was identical and b* decreased. This effect differs from that of irradiated pork. The decrease of the pH was identical for both irradiated and nonirradiated samples. This change may be caused by maturation of fish flesh.     

Multi-response optimization of mechanical and comfort properties of bi-stretch woven fabrics using grey relational analysis in Taguchi method

The present paper envisages the multi-response optimization of certain factors like elastane linear density, fabric thread density and weave float on some mechanical, (i.e. stretch %, recovery %) and comfort (i.e. air permeability) properties of bi-stretch woven fabrics, under L₁₈ orthogonal array in Taguchi design. Fabric samples were produced using elastane core-spun cotton yarns both in the warp and weft. The elastane linear density, fabric thread density and weave float size were used as predictor variables, while fabric air permeability, stretch and recovery were taken as response variables. Two different elastane linear densities, i.e. 44 dtex and 78 dtex, 3 different thread densities and 3 different weave designs, i.e. 1/1 plain, 2/2 z-twill and 3/3 z-twill were used. The results have been analysed using grey relational analysis for the identification of an optimum level of process factors. Furthermore, using analysis of variance method, significant contributions of predictor variables were determined.     

Study of tensile properties of plain-woven fabrics in all-directional using energy method,Part II: experimental verification

Abstract

In the previous part of this series, ‘Comprehensive Tensile Modulus (CTM)’ was introduced as an important modulus to express the force-elongation behavior of plain-woven fabrics when the force is imposed on the fabric and extended it simultaneously in all directions. A theoretical model was presented to predict this modulus in the initial elastic region. In order to verify the accuracy of the model, a novel tensile test method was developed to measure load-extension curve of the fabric samples under the proposed loading condition. Thereafter, six plain-woven fabrics were produced with different raw materials and densities then were washed and dried to reach the relaxed state. Fabric samples were tested using the new method. The fabric’s experimental Comprehensive Tensile Modulus (CTMs) were determined from the results of the tests in all directions by the nine-point central difference method, and the calculated data were analyzed statistically to obtain the experimental CTM of fabrics. Reasonable agreement between theoretical and experimental results confirmed that the generated model is capable to predict the CTM index as a tensile property of plain-woven fabrics, adequately. The comparison between results of the theoretical model and experimental test shows that maximum error of prediction is 8.5% which is recorded for the grey fabric sample constructed from the OE Cotton yarn with nominal yarn count 24 Ne. Also, maximum experimental comprehensive tensile modulus (17.9 N/mm) is for the grey fabric sample constructed from the high tenacity continuous filament of Nylon with nominal yarn count 900den, in one millimeter extension with maximum modulus in warp and weft directions, that is, 5.6 N/mm and 6.6 N/mm in the same extension in the initial linear elastic region, respectively.     

Elastic Recovery and Performance of Denim Fabric Prepared by Cotton/Lycra Core Spun Yarns

ABSTRACT

Elastic performance coefficient (EPC) and recovery behavior of denim fabrics prepared with cotton/lycra core spun stretch yarns have been presented in this article. The denim fabrics are woven as broken twill weaves in an air-jet weaving machine by the insertion of core spun yarns (lycra filament in core, cotton fiber on sheath) as weft and using 100% cotton yarns as warp. The effect of linear density and stretch percentage of the core spun weft yarns on tensile and recovery behavior of denim fabric have been investigated by employing full factorial design of experiments. It has been observed that the tensile strength and EPC of fabric increase with decrease in linear density and stretch percentage of the core spun stretch yarn. The immediate elastic recovery and delayed elastic recovery increase with decrease in linear density and stretch percentage of the yarns.