SELECTING COTTON BALES BY SPINNING CONSISTENCY INDEX AND MICRONAIRE USING ARTIFICIAL NEURAL NETWORKS
This paper presents a method of selecting cotton bales to meet the specified ring yarn properties using artificial neural networks. Five yarn properties and yarn count were used as inputs, whereas the Spinning Consistency Index (SCI) and micronaire were the outputs to the neural network models. Bales were selected according to the predicted combinations of SCI and micronaire. The properties of yarns spun from selected bales show good association with the target yarn properties.
ELECTRICAL PROPERTIES OF CONDUCTIVE POLYMERS: PET - NANOCOMPOSITES' FIBRES
Researches in the field of conductive polymers have attracted considerable attention for more then 20 years. Among the conductive polymers, polyaniline and polypyrrole have drawn considerable interest because of their economical importance, good environmental stability and satisfactory electrical conductivity when doped. On the other hand, electrically conductive materials such as aluminium powder, graphite and carbon nanotubes have very interesting conductive properties and are promising in the synthesis of new composite conductive materials. In almost all studies, conducting polymer films are developed and then electrical and mechanical properties are tested.
In our paper, the conducting polymer fibres have been obtained by melt mixing and chemical coating on the fibres. Different conductive materials have been used in order to obtain conductive polypropylene-based fibres with specific electrical and mechanical properties. The electric conductivity and morphological characteristics of these fibres have been investigated and the results are discussed.
The originality of our approach lies in our having created conductive fibres based on conductive polymers. These fibres are intended for use in creating conductive yarns and realising connections in smart clothing, or producing conductive fabrics which can be used as electromagnetic shields.
These developments have been carried out in order to create new multifunctional textile structures for different applications in the field of intelligent and communication apparel or other similar branches.
INTEREST OF A COMPOUND YARN TO IMPROVE FABRIC PERFORMANCE
The market for protective clothing is growing in many fields, including flame resistance clothing, cut-resistance gloves and so on. High-performance fibres such as aramides are known to be flameproof and resistant to mechanical impacts, but they are sensitive to UV.The purpose of this study was to produce compound yarns with the advantageous properties of aramides and insensitive against UV radiation. We obtained such yarns by means of a friction process (FEHRER), a non-conventional spinning process. The yarn obtained, denoted as DREF yarn, developed by us is a combination of wool and poly-p-phenylenediamine-terephtalamide fibres (Kevlar®29). The compound yarn is composed of a core in Kevlar® yarn, coated by wool fibres. The DREF yarns were then knitted; the articles obtained have interesting properties such as flame retardancy, good-handle, cutting resistance, and are also UV-resistant.
THE MECHANISM OF END BREAKAGE IN RING SPINNING: A STATISTICAL MODEL TO PREDICT THE END BREAK IN RING SPINNING
The mechanism of end breakage in ring spinning is a complex phenomenon, and is entirely different from the yarn failure mechanism during a tensile test. In this paper a possible mechanism of end breakage is reported. A statistical model is developed for predicting the likely end breakage rate in ring spinning. The important factors in governing end breaks are the mean yarn strength, yarn strength variation, mean value of the peak spinning tensions and the variation of yarn mass irregularity. Some practical aspects have also been discussed to tackle the problem of when the breakage rate suddenly increases.
MODELLING AND SIMULATION OF THE MECHANICAL BEHAVIOUR OF WEFT-KNITTED FABRICS FOR TECHNICAL APPLICATIONS Part III: 2D hexagonal FEA model with non-linear truss elements
This paper is in four parts. The first is related to general considerations and experimental analyses, and each of the others is related to different approaches to theoretical analyses of the mechanical behaviour of weft-knitted fabrics and weft-knitted reinforced composites made of glass fibre. The objective is to find ways of improving the mechanical properties and simulating the mechanical behaviour of knitted fabrics and knitted reinforced composites, so that the engineering design of such materials and structures may be improved.
In Part III the second model is presented, and this is a 2D model based on FEA (finite element analyses).
A plain weft-knitted fabric, based on the simple loop structure, is simplified and represented by a 2D hexagonal structure constructed by non-linear truss elements. The characteristics of the truss elements for FEA simulation are obtained from experimental results through an analytical method when a loop is converted to a FEA model. The elongation deformation is simulated in one, two and multiple directions. The model can also be used to calculate a planar knitted fabric for deformation to fit a 3D spherical mould.
INDIRECT DETERMINATION OF THE LOAD INTENSITY PARAMETERS ACTING ON THREADS DURING KNITTING BY MEANS OF TESTING STRUCTURE CHANGES IN SPECIAL PREPARED YARN
Intensive loading of yarn processed by knitting influences the efficiency of the process and the quality of the knitted fabrics which are manufactured. It is frequently necessary to determine their value and eliminate the negative effect if such a necessity arises. In this work we propose an indirect method for measuring and testing loads and load changes acting on the yarn during the knitting process. By means of this method it is possible to see which parts of the stitch structure are the most loaded, and thus predict the consequences of these loads on the yarn structure. Special knitted thread-bands are used, which are photographed at the moment of knitting or scanned after the unknitting of the knitted fabric. The structure of these bands easily imprints 'copies' of the value and the type of loads.
THE POSSIBILITY OF LOW-TEMPERATURE PLASMA TREATED WOOL FABRIC FOR INDUSTRIAL USE
In this paper, low-temperature plasma (LTP) treatment was applied to a wool fabric. The LTP-treated wool fabric was tested according to different international standard testing methods, and the results were compared with the industrial requirements (ASTM requirements). It was revealed that the LTP-treated wool fabric did meet industrial requirements. The results of the investigation are thoroughly discussed in this paper.
DIFFUSION OF DISPERSE DYES INTO SUPERMICROFIBRES
All dyers share the common goal of achieving the correct shade as early as the first dyeing. But the dyeing process is very complex, being characterised by the diffusion-controlled sorption of dyes that depends on several physicochemical parameters.
Moreover, the dyeing properties relating to microfibres and conventional fibres are caused by different properties such as the exposed surface area and the crystallinity index.
Wilson and Hill developed equations describing the uptake rate of disperse dyes by a cylindrical fibre model as a function of the diffusion coefficient and the nature of the dyebath. The inverse of Shibusawa's polynomial approximation of Hill's and Wilson's equation is used to compute the diffusion coefficient, which depends on the initial dye concentration, the time and the fibre count at a fixed temperature.
In this paper, the sorption isotherms, the diffusion coefficient, the dye concentration evolution into the fibres and the dyeing uptake rate are computed from experimental results for conventional fibres, microfibres and supermicrofibres. The sorption isotherms and the diffusion coefficient evolutions as a function of time, initial dye concentration and temperature for supermicrofibres are discussed by considering the surface area and the diffusional boundary layer's influence. Important differences in the dyeing properties are observed, depending on the fibre count, which should be useful in the optimisation of the supermicrofibre dyeing process. The aim is to provide a tool for dyeing practitioners to increase dyeing reproducibility and to improve the performance of 'right-first-time' production.