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Dref-3 friction spun core yarns produced using staple fibre yarn as the core, e.g. Jute core yarn wrapped with cotton fibre, have poorer mechanical properties compared to the core yarn itself. The purpose of this study was to understand the structure of such yarns, that will lead to the optimization of fibre, machine and process variables for production of better quality yarn from the Dref-3/3000 machines.

The Dref spinning trials were conducted following a full factorial design with six variables, all with two operative levels. The Dref-3 friction spun yarn, in which the core is a plied, twisted ring yarn composed of cotton singles and the sheath, formed from the same cotton fibres making the singles, has been examined. The structures have also been studied by using the tracer fibre technique.

It was observed that rather than depending on the plied core yarn, the tensile properties of the Dref-3 yarn are significantly determined by the parameters those affect the constituent single yarn tensile properties, i.e. the amount of twist and its twist direction, yarn linear density and the sheath fibre proportion used during the Dref spinning in making the final yarn. Further, when the twist direction of single yarn, double yarn and the Dref spinning false twisting are in the same direction, the produced core-sheath yarn exhibits better tensile properties.

The understanding of the yarn structure will lead to optimized production of all staple fibre core Dref spun yarns.

The research work may lead to utilization of coarse and harsh untapped natural fibres to the production of value-added textile products.

Though an earlier research has reported the effects of sheath fibre fineness and length on the tensile and bending properties of Dref-3 friction yarn, the present study is the first documented attempt using the tracer fibre technique to understand Dref-3 yarn structure with plied staple fibrous core.

The paper aims to provide an investigation about the effect of some selected production parameters such as core yarn type, sheath sliver type and total yarn count factors on core spun vortex yarns' evenness, imperfection and tensile properties. Hence it is aimed to contribute to the literature in vortex spinning where there are limited works related to core-spun vortex spinning.

The paper evaluates the effect of core yarn type, sheath sliver type and total yarn count factors on yarn evenness, imperfections, hairiness and tensile properties. Completely randomised three-factor analysis of variance (ANOVA) was conducted in order to evaluate the effect of core yarn type, sheath sliver type and linear yarn density on core spun vortex yarns' evenness, imperfection and tensile properties at significance level of 0.05. SNK tests were also performed for observing the means of each parameter. Correlation analysis was also conducted to reveal some relationships between yarn evenness and yarn tensile properties.

In this paper, significant factors related to some production parameters affecting the core-spun vortex yarns' evenness, imperfection, hairiness and tensile properties were found.

There are limited works related to effect of selected production parameters on yarn evenness, Imperfections and Tensile Properties of Hybrid Vortex Yarns.

In recent times, the usage of elastane-containing denim garments has increased, as it provides fit and comfort both at the same time. The purpose of the study is to understand the effect of abrasion on the durability of comfort related to body movement and shape retention property of the stretch-denim fabric.

The paper investigates the effect of abrasion on the initial tensile properties, recovery and resilience properties of the stretch-denim fabric. Further, to analyse the effect of the composition of the elastane yarn, three different types of elastane yarns having different types of sheath (covering) fibre, structure and different levels of elastane content have been used in the weft.

The comfort related to body movement and the shape retention properties of the stretch-denim fabric got affected due to abrasive damage. The elastane yarn composition and structure played an important role in determining the extent of the change in such properties during abrasion. The fabric with a higher level of elastane content suffered a greater loss in shape-retention properties due to abrasion. The extent of mass loss in stretch-denim fabric does not always correlate to the extent of loss in the comfort and shape-retention properties.

Most of the earlier studies have investigated the effect of abrasion on the durability aspect of the stretch-denim fabric. In a practical scenario, the stretch-denim garments are rarely discarded due to tearing or change in appearance but mainly due to bagging, i.e. distortion in shape after usage. Thus, the study on the combined effect of the abrasion and cyclic loading on the comfort and shape-retention properties will help to predict the performance of the apparel during usage.

In recent times, stretch denim garments have become very popular amongst consumers as the garment is able to provide body fit and body comfort at the same time. The purpose of this study is to investigate the effect of abrasion on the change in surface appearance, mass loss and ultimate tensile properties of the stretch denim fabric in different directions (warp, weft and biased).

After abrading the fabrics in three different directions (warp, weft and biased), the loss in ultimate tensile properties, mass loss and surface appearance has been investigated in the respective directions of abrasion (warp, weft and biased). The study also encompasses the effect of different types of stretch yarn with varying levels of elastane content on such unidirectional abrasive damage.

It is seen that with the same level of abrasion cycles, the fabric's response in terms of mass loss and loss in ultimate tensile properties are different in different directions. The mass loss due to abrasion in biased direction is found to be minimum. The loss in ultimate tensile properties due to abrasion was highest in the weft direction. It is also found that the higher mass loss due to abrasion does not always result in a greater loss in ultimate tensile properties. The composition and the structure of the weft yarn significantly affected the extent of the mass loss and the loss in ultimate tensile properties during abrasive damage.

The impact of abrasive damage in terms of mass loss and loss in tensile strength along the different directions of denim fabric has not been explored till date. Abrasion of fabric can be done both in multi-direction (Lissajous motion) as well as in uni-direction (linear motion). The multidirectional abrasion provides a holistic or comprehensive idea of the fabric's response to the abrasive damage but does not take into consideration the fabric's anisotropic response to the abrasive damage. Most of the earlier investigation related to abrasive damage of denim fabric has been done in instruments where the motion of the abrader is multidirectional (Lissajous) in nature. For greater depth of understanding about the fabric performance under abrasive damage along the various direction (warp, weft and biased), unidirectional abrasion is conducted in this study.

In this research, recycled fibres (RF) were used to produce three types of two-component yarns such as cotton covered by RF "R-C" core yarn, RF covered by cotton "C-R" core yarn, and randomly blended "mixed" yarns. In the case of "R-C" and "C-R" core yarns, the core component is perfectly covered by sheath fibres and the appearance of these yarns is the same as that of yarns made with sheath fibres. The results show that "R-C" yarns are stronger than other types, while; there is no significant difference between the strength of "C-R" and "mixed" yarns. Also, the strength of all types of two-component yarns is higher than that of 100% RF yarns, while their elongation is almost as same as that of 100% cotton yarns, which are lower than that of RF yarns. Also the irregularity of all of the twocomponent core yarns is better than that of RF yarns. From the results, we conclude that, with our techniques, we can produce on a friction spinning machine two-component core yarns and blend yarns from staple fibres with acceptable appearance and tensile properties.

This paper outlines the innovations in high functional and high performance fibres for applications in protective clothing, including fibres for flame and heat protection. It also describes some typical woven and non‐woven constructions for such applications. And presents the trends in producing smart textile materials, capable of interacting with human/environmental conditions.

Review of a Broad Selection of Plastics Products being Utilized by the Aircraft Industry emphasizing the Importance of these Materials. The preceding seven articles have covered specific aspects of the application of plastics to aircraft and the industry. We now broaden our horizon to review in general terms a selection of products and the applications which they have found. It is obviously impossible to describe every application of plastics to aircraft in an issue such as this, but it is hoped that the selection provided will give a representative cross‐section, emphasizing the growing importance of this class of materials.

This paper aims to design and test a system capable of coaxial fused deposition modelling (FDM) and assess the coaxial fibres produced for their coaxial concentricity. The goal is to achieve concentricity values below the literature standard of 15 per cent.

This research discusses the design of the coaxial nozzle internal geometry and validates the modelling process by using computational fluid dynamics to assess its flow profile. Sequentially, this paper discusses the abilities of current additive manufacturing (AM) technology in the production of the coaxial nozzle.

The methodology followed has produced coaxial fibres with concentricity values as low as 2.89 per cent and also identifies a clear speed suitable for coaxial printing using polylactic acid (PLA) as the internal and external materials.

The concentricity of the printed fibres is heavily influenced by the feed rate for the thermoplastic feedstock. This in turn alters the viscosity of the material to be printed, implying that a relationship exists between feed rate and print temperature, which can be further optimised to potentially obtain higher concentricity values.

This paper adds reliability and repeatability to the production of coaxially printed structures, the likes of which has numerous potential applications for biological printing.

The outcomes of this study will provide an AM platform to alter the paradigm of biofabrication by introducing a new level of versatility to the construction of biofabricated structures.

The purpose of this paper is to analyse the seersucker fabrics from the point of view of their ability to ensure the thermo-physiological comfort. It was investigated how the kind of the weft yarn and seersucker structure influence the air permeability and thermal insulation properties of the fabrics.

The paper presents the investigations of the typical seersucker fabrics made of the same set of warps and different weft yarns. Fabrics were manufactured on the same loom with two warp beams. Next they were finished by the same way including washing, drying and stabilisation processes. Fabrics were measured in the range of their air permeability using standard test method. Thermal insulation properties of fabrics were measured in dry and wet state by means of Alambeta. Surface topography of the seersucker fabrics was analysed using 3D laser scanning.

On the basis of the obtained results it was stated that due to the puckered structure the seersucker fabrics are characterised by high thermal resistance, several times higher than the thermal resistance of typical flat woven fabrics. The seersucker fabrics are characterised by very low value of the thermal absorptivity in wet state at the level appropriate for typical flat fabrics in dry state. It confirmed that the seersucker fabrics ensure the physiological comfort. Application of the elastomeric yarn in weft caused significant tightening the fabric structure. It resulted in low air permeability, fabric stiffness and unpleasant hand.

As a limitation of the investigation of the seersucker fabrics in wet state we can mention the surface topography of the fabrics. It made wetting the fabrics difficult before measuring. It is necessary to elaborate precise procedure of preparation of seersucker fabrics before their testing in the wet state.

Performed investigations showed that the seersucker fabrics have a big potential to be comfortable. By an appropriate designing of their structure it is possible to achieve very good comfort-related properties even without application of innovative comfort-oriented yarns.

The originality of the paper is based on the fact that the measurement was performed for the seersucker fabrics. The fabrics are characterised by the unique structure which influences their appearance and utility properties. It caused that they are willingly applied in different kinds of clothing. Till now any results of comfort-related properties of such kind of the woven fabrics have not been published.

I TAKE it as a great compliment to be asked to open this Exhibition, the Corrosion and Metal Finishing Exhibition. Additionally, I regard the occasion as one on which the President of the Society of Chemical Industry, who happens at this time to be myself, can very usefully and indeed very appropriately take a great interest.