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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.

In spinning industries, selection of the most appropriate fibre for yarn manufacturing plays an important role for achieving an optimal mix of several yarn characteristics, like maximum tenacity, elasticity and spinning ability; and minimum unevenness and hairiness. Identification of the best suited cotton fibre from a set of available alternatives in presence of different conflicting physical properties is often treated as a multi-criteria decision-making (MCDM) problem. The paper aims to discuss this issue.

In this paper, the preference ranking organisation method for enrichment of evaluations (PROMETHEE) and geometrical analysis for interactive aid (GAIA) methods are integrated to solve a cotton fibre selection problem. The PROMETHEE II method ranks the alternative cotton fibres based on their net outranking flows, whereas GAIA acts as a visual aid to strongly support the derived selection decision. The weight stability intervals for all the considered fibre properties (criteria) over which the position of the top-ranked cotton fibre remains unchanged are also determined.

The clusters of cotton fibres formed in the developed GAIA plane act as a yard stick for their appropriate grading to aid the blending process. The ranking of 17 cotton fibres as achieved applying the combined PROMETHEE-GAIA approach highly corroborates with the observations of the past researchers which proves its immense potentiality and applicability in solving fibre selection problems.

Two MCDM methods in the form of PROMETHEE II and GAIA are integrated to provide a holistic approach for cotton fibre grading and selection while taking into consideration all the available cotton fibre properties.

The purpose of this research is to design 3D print and analyze mechanical as well as microstructural behavior of interlaced fibrous structures using Dremel 3D45 additive manufacturing (AM) machine.

A series of plain and twill weave fabrics are designed using computer-aided design software Solidworks and printed using fused deposition modeling machines to determine the best model that could be printable. The structures were designed in such a way that the fabricated yarns with pure (PLA) were not sticking to each other in the fabric structure. The specimens were printed in vertical orientation and then tensile and three-point bending (flexural) tests were conducted for twill weave fabrics.

The tests showed that the mechanical strength was higher in the warp direction than in the weft direction. This difference was because of printing of continuous filament-like yarns in the warp direction and staple-like yarns in the weft direction. This orthotropic property of the material was verified by analyzing its microscopic structures via optical microscope.

Future work should include improvement of the structure and exploration of different polymers and their composites to increase the tensile, bending and other strengths to make the 3D-printed structures more flexible and stronger. Future research should also focus on the large-scale manufacturing of 3D printed fabrics.

This paper supports work on wearable 3D-printed fabrics. The 3D-printed fabric will also contribute to new applications and products such as liquid filters.

The research done in this work is new and original. This paper contributes to new knowledge by providing a better understanding of polymers and their 3D printing capabilities to form a complex fabric structure.

Three-dimensional (3D) printing, one of the important technological pillars of Industry 4.0, is changing the landscape of future manufacturing. However, the limited build volume of a commercially available 3D printer is one inherent constraint, which holds its acceptability by the manufacturing business leaders. This paper aims to address the issue by presenting a novel classification of the possible ways by which 3D-printed parts can be joined or welded to achieve a bigger-sized component.

A two-step literature review is performed. The first section deals with the past and present research studies related to adhesive bonding, mechanical interlocking, fastening and big area additive manufacturing of 3D printed thermoplastics. In the second section, the literature searches were focused on retrieving details related to the welding of 3D printed parts, specifically related to friction stir welding, friction (spin) welding, microwave and ultrasonic welding.

The key findings of this review study comprise the present up-to-date research developments, pros, cons, critical challenges and the future research directions related to each of the joining/welding techniques. After reading this study, a better understanding of how and which joining/welding technique to be applied to obtain a bigger volume 3D printed component will be acquired.

The study provides a realistic approach for the joining of 3D printed parts made by the fused deposition modeling (FDM) technique.

This is the first literature review related to joining or welding of FDM-3D printed parts helping the 3D printing fraternity and researchers, thus increasing the acceptability of low-cost FDM printers by the manufacturing business leaders.

The purpose of this paper is to investigate the use of steam in order to replace air in the production of spun-like textured yarns. Further, this paper analyse the effect of production speed on process and textured yarn properties.

An existing air-jet texturing machine was modified to supply either air or steam to the texturing nozzle. Using standard commercial nozzles, both air-jet and steam-jet textured yarns were manufactured by varying production speed.

It can be concluded that steam can be used as an alternative fluid for air in making spun-like textured yarns. Results show that yarn parameters for steam-jet texturing show a similar trend to those of air-jet texturing relative to the production speed. Further, sewing threads made from steam-jet textured yarns showed good sewability up to the speeds of 350 m/min.

Only the effect of production speed on process and yarn parameters is discussed in this paper. Production speed was limited to 350 m/min due to machine constraints.

Steam is more economical than air to manufacture spun-like textured yarn at commercial pressures such as 8 bar. Steam-jet textured yarns could be used for commercial applications such as sewing threads at competitive speeds. Further, steam could be generated using sustainable and renewable fuel sources such as biomass.

This research introduced steam as an alternative fluid for air in manufacturing spun-like textured yarns.

Under fix-position preload, the high rotation speed of the angular contact ball bearing exacerbates the frictional heat generation, which causes the increase of the bearing temperature and the thermal expansion. The high rotation speed also leads to the centrifugal expansion of the bearing. Under the thermal and centrifugal effect, the structural parameters of the bearing change, affecting the mechanical properties of the bearing. The mechanical properties of the bearing determine its heat generation mechanism and thermal boundary conditions. The purpose of this paper is to study the effect of centrifugal and thermal effects on the thermo-mechanical characteristics of an angular contact ball bearing with fix-position preload.

Because of operating conditions, elastic deformation occurs between the ball and the raceway. Assuming that the surfaces of the ball and channel are absolutely smooth and the material is isotropic, quasi-static theory and thermal network method are used to establish the thermo-mechanical coupling model of the bearing, which is solved by Newton–Raphson iterative method.

The higher the rotation speed, the greater the influence of centrifugal and thermal effects on the bearing dynamic parameters, temperature rise and actual axial force. The calculation results show that the effects of thermal field on bearing dynamic parameters are more significant than the centrifugal effect. The temperature rise and actual axial force of the bearing are measured. Comparing the calculation and the experimental results, it is found that the temperature rise and the actual axial force of the bearing are closer to reality considering thermal and centrifugal effects.

In the past studies, the thermo-mechanical coupling characteristics research and experimental verification of angular contact ball bearing with fix-position preload are not concerned. Research findings of this paper provide theoretical guidance for spindle design.

The study aims to the distribution rule of lubricating oil film of full ceramic ball bearing and improve its performance and life.

The paper established an analysis model based on the fluid–solid conjugate heat transfer theory for full ceramic ball bearings. The distribution of flow, temperature and pressure field of bearings under variable working conditions is analyzed. Meanwhile, the mathematical model of elastohydrodynamic lubrication (EHL) of full ceramic ball bearings is established. The numerical analysis is used to study the influence of variable working conditions on the lubricant film thickness and pressure distribution of bearings. The temperature rise test of full ceramic ball bearing under oil lubrication was carried out to verify the correctness of simulation results.

As the speed increased, the oil volume fraction in full ceramic ball bearing decreased and the surface pressure of rolling element increased. The temperature rise of full ceramic ball bearings increases with increasing speed and load. The lubricant film thickness of full ceramic ball bearing is positively correlated with speed and negatively correlated with load. The pressure of lubricating film is positively correlated with speed and load. The test shows that the higher inner ring speed and radial load, the higher the steady-state temperature rise of full ceramic ball bearing. The test results are in high agreement with simulation results.

Based on the fluid–solid conjugate heat transfer theory and combined with Reynolds equation, lubricating oil film thickness formula, viscosity temperature and viscosity pressure formula. The thermal analysis model and EHL mathematical model of ceramic ball bearings are established. The flow field, temperature field and pressure field distribution of the full ceramic ball bearing are determined. And the thickness and pressure distribution of lubricating oil film in the contact area of full ceramic ball bearing were determined.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2023-0126/

The purpose of this study was to produce yarns from three different spinning techniques, i.e.Murata Vortex Spinning (MVS) ring spinning and rotor spinning. Those yarns were then used to produce fabrics. Then, the effect of silicone softener on tactile comfort of fabric was investigated.

Three different yarns, i.e. Ring, Rotor and MVS yarns, were used to make fabrics using CCI sample loom which were then subjected to post treatments like desizing, scouring and bleaching. After the completion of the dyeing process, silicone-based softener was used to improve the hand feel of fabrics. The structures of three yarns were evaluated using Scanning electron microscopy. The fabrics were evaluated against compression, bending and surface properties using Kawabata evaluation system.

The fabric made of MVS yarn depicted more geometrical roughness, coefficient of friction and bending rigidity but less compressibility as compared to fabrics made with other yarns. It was observed that softener concentration has a direct relationship with thickness and bending rigidity of the fabric, and inverse relationship with coefficient of friction and geometrical roughness of the fabric.

MVS yarn has some superior properties over rotor and ring spun yarn like high production rates, high resistance to pilling, clear appearance and stability against deformation but has disadvantage that it has less compressibility. Therefore, softener is applied on the fabric, to address this issue, so that it could also be used for apparels application.

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.

The purpose of this study is to explore the potential of Cordyline Australis fibers as an alternate raw material for textile.

The water retting method was used to extract the fiber. Cordyline Australis fibers were characterized in terms of the morphology of fibers (fiber cross-sectional and longitudinal), fiber chemical functional groups, tensile strength and elongation, fineness, fiber length, moisture regain and friction coefficient.

Cordyline Australis fiber strands consist of several individual fibers. At the longitudinal section, the fiber cells appeared as long cylindrical tubes with a rough surface. The cross-section of the Cordyline Australis fibers was irregular but some were oval. The key components in the fibers were cellulose, hemicellulose and lignin. The tensile strength of the fiber per bundle was 2.5 gf/den. The elongation of fibers was 13.15%. The fineness of fiber was 8.35 Tex. The average length of the fibers was 54.72 cm. Moisture Regain for fiber was 8.59%. The friction coefficient of fibers was 0.16. The properties of the fiber showed that the Cordyline Australis fiber has the potential to be produced into yarn.

To the best of the author's knowledge, there is no scientific article focused on the Cordyline Australis fibers. Natural fibers from the leaves of the Cordyline Australis plant could be used as an alternate material for textile.