कपड़ा विज्ञान और इंजीनियरिंग जर्नल

The effects of air velocity, air-gap thickness and configuration on heat transfer of a wearable convective cooling system were modeled using a 2-D Computational Fluid Dynamics (CFD) simulation. Three different configurations, one with eight 1 cm fans (8 × 1 model); one with four 2 cm fans (4 × 2 model); and one with four 1 cm fans (4 × 1 model) were studied at different inlet air velocities of 0.25 m/s, 0.5 m/s, 0.75 m/s and 1.0 m/s and with air gaps of 3 mm, 7 mm and 11 mm. The simulations showed that the convective and evaporative heat transfer coefficients varied with a power function of inlet air velocity, but the exponent was larger than reported in the literature. At lower air velocities, the heat transfer coefficients increased as the gap between the skin and the undergarment widened. At higher inlet air velocities, 3 mm and 11 mm air gaps showed the highest heat transfer values. The ratios of the heat transfer coefficients of the 8 × 1 and 4 × 2 models to the 4 × 1 models were both less than 2 indicating that doubling the inlet airflow does not double the heat transfer capability. The ratios of convective to evaporative heat transfer coefficients were around 8.63 K/kPa (SD 0.25 K/kPa), and were independent on the air velocity and configurations of the cooling system, suggesting that convective and evaporative heat transfer are fully coupled. This ratio also shows that the vapor permeability index of our system is around 0.52. Using slightly larger fans should be more effective in enhancing heat transfer than using more fans.

The number of violent situations against security agents using cut and puncture elements, like knives and needles, are increasing daily all over the world. There is a real need for the development of flexible materials able to protect these security professionals without compromising their comfort in different working conditions. The aim of this study is to develop single-layer weft knitted fabrics for cut and puncture protection to be used as protective clothing. Three different weft knitted structures were selected (single jersey, crepe, and moss tuck stitch) in order to study the effect of the yarn arrangement on cut and puncture performance. Different knitted fabrics have been produced with different materials including ultra-high molecular weight polyethylene, para-aramid, high tenacity polyester, high tenacity polypropylene and high tenacity polyamide. In order to study the performance of each structure in combination with the different materials, samples were tested according to EN 388. It was proved that due to the tuck stitches, crepe and moss structures improved cut and puncture performances in comparison with jersey structures. The conical puncture resistance was mainly attributed to the structure (high friction between the yarns and within the yarns due to the dense structure), the knife puncture resistance was mainly attributed to the strength of the yarns, and the cut resistance was mainly attributed to the structure (stretching and thickness) and to the mechanical properties of the yarns. Based on the experimental results and according to EN 388 test classification, moss tuck stitch structure produced with ultra-high molecular weight polyethylene presents the highest cut resistance, classified as level 5, and the highest conical puncture resistance, level 4. Crepe structure produced with para-aramid presents the highest knife puncture resistance. It is suggested the use of single layer moss tuck stitch fabric produced with ultra-high molecular weight polyethylene as protective clothing.

High-wage countries are on the brink of change, due to social and technological effects. In this paper, we will first give an outlook on both these effects concerning the German textile industry. Second, we will shortly describe the interdisciplinary build-up of our research group which influences the way how we address our research issues. Finally, we will outline two prototypical applications that serve as demonstrators for further user tests and subsequent developments.

Experimental studies were conducted on woven fabrics indicate that the yarn tension is the most important factor affects weaving performance and fabric property. This research has been examined the influence of fabric variables on warp tension, There are two advantages to applied the suitable tension on warp yarn, the first is to increase loom producing by decrease cutting of warp yarn, by suitable warp tension value. While the second is to improve the fabric quality by increase its resistance to tensile and friction. Chenille fabric was chosen for the test, because it is composed of a complex weave structures, on the other hand it is one of the most commonly used fabrics in the practical field. Four fabric variables have been studied on warp tension, which are (weft density, weft count, weft type and weave structure). Experimented mechanical properties are (vertical tensile resistance, horizontal tensile resistance and friction resistance). Research has been indicated that relationship between weft density with warp tension is an inverse relationship, while the relationship between weft count and weave float with warp tension is a direct relationship, and there is no effect of the weft type with warp tension. Finally, we have been concluded an equation for each previous relationship, by using those equatio† Ô– will get a fabric with best mechanical properties and high loom production.

The dyeing behavior of segmented polyurethane containing copolymerized polyethylene glycol soft segments was investigated. Four types of segmented polyurethane were prepared by controlling the aggregation of the hard segments and the mobility of polyethylene glycol in the soft segments. Dyeing rate curves and sorption isotherms were obtained for direct dyes at various temperatures along with the swelling ratios of the different segmented polyurethane samples. The sorption of CI Direct Red 28 by these samples is shown to decrease with increasing dyeing temperature, with the swelling ratio of the segmented polyurethane film also decreasing. Changes in the tensile strength of the films before and after dyeing with CI Direct Red 28 are shown to be related to the degree of aggregation of the hard segments, as well as to the amount of dye used.

The physical properties of cotton crêpe fabrics with highly twisted weft yarn (2200 twists per meter) were evaluated after special embossed finishing to generate piqué. The effect of piqué was investigated as the main factor affecting the tensile properties of the sample fabrics under varied relative humidity. First, the mechanical and surface properties were measured using the Kawabata Evaluation System for Fabrics under standard room conditions, and then, the other physical properties were examined. The existence of piqué in the crêpe texture significantly changed the samples’ tensile properties, such as tensile energy and extensibility at maximum applied load (EM) in the weft direction. Additional tensile measurements were carried out under varied relative humidity (10-90% RH) at 25°C. The crêpe fabrics with piqué had higher EM and residual strain values than the non-piqué samples under all RH conditions. In particular, the effect of piqué on EM became obvious at 90% RH.

Wool yarns are dyed with natural colouring matter extracted from Cochineal, Turmeric and Madder using exhaustion method. These dyed yarns are pre-mordanted with different types of mordants. Different measurements have been carried out for the dyed wool yarns after exposure to air pollution in residential site (Kalla region) for one year. These measurements values include colour data (K/S, L*, a*, b*, ΔE, hue and chroma) and physical properties (tensile strength, tenacity and elongisity). Also, the present work studied the air pollution in (Kalla region), through determination of the suspended and deposited particulate matter and sulpher dioxide concentrations for different periods of time in one year

Mulberry is a plant that is grown for silkworm rearing. It is the exclusive food for the silkworm, which during its larval life is reared for silk production. Mulberry forms the basic food material for silkworms. Production of mulberry leaves on scientific lines is essential for organizing sericulture on sound economic lines. It is estimated that one metric ton of mulberry leaves is necessary for the rearing of silkworms emerging out of one case of eggs which will yield about 25 kg to 30 kg of cocoons of high quality. The findings show that mulberry plant can grow and thrive very well in Kenya because of very good climatic conditions that are favorable for mulberry plant. It is worth nothing however that mulberry tree can grow in a variety of climatic conditions. As a result of successful production of mulberry, silk production training is needed for skilled labour in mulberry growing and silk worm rearing in these high production areas of the country with similar climatic condition to the experimental area of Eldoret. Sericulture has the potential of poverty eradication and economic empowerment especially for women and youth in Kenya because it is a labour intensive venture. Silk production has the potential of serving as a supplement to the textile industry in Kenya due to the the dwindling cotton production. Despite the fact that the sericulture has been going on in Kenya for more than 45 years, there has been several challenges that has crippled the success of sericulture. The major bottleneck is the lack of domestic demand for the finished products due to unclear goals in quality and minimal product awareness, lack of well established government policies and lack of capacity and insufficient technical skills on mulberry and silkworm rearing. The study recommends that proper agronomical practices should be used to increase yield, intensive research is required on the available species of mulberry in Kenya. As a result of successful production of mulberry, training is needed for skilled labour in mulberry growing and silk worm rearing for high production.

For expanding the utilization of several high-performance aromatic polymeric fibers, e.g., poly p-phenylene benzobisoxazole (PBO, Zylon®), poly p-phenylene terephthalamide (PTA, Kevlar 29®), and polyarylate (PA, Vectran®), direct carbonizing and graphitizing behaviors have been investigated. The PBO-based carbon fiber showed a typical radial texture on its fracture surface, and the graphitization degree (P1) reached 0.35 and crystallite sizes of Lc(002), La(110) after graphitization exceeded 30 nm. On the other hand, the P1 indices of the graphitized carbon fibers from PTA and PA were no more than 0.15. However, a low P1 value is preferable for the production of activated carbon fibers (ACF). In addition, on the surface of the PA-based carbon fibers produced at 900°C, some fine mesh-like morphologies were observed indicating the formation of a porous carbon structure. In contrast, for the PTA-based carbon fibers the development of radial texture could be seen only partially on the fracture surface, and porous morphologies were not recognizable. It was confirmed that the direct carbonization was enough to convert PA fibers into ACF. The BET surface area of the PA-based carbon fibers increased up to 900~1,000 m2/g after the direct carbonization at 900 oC, and exceeded 1,000 m2/g easily when activated.

A new geometrical model of terry woven fabrics made with cotton yarn has been analyzed to understand the pile yarn path. Theoretical model has been created to predict the porosity of terry woven fabrics depending on their geometrical such as warp and weft spacing pile length pile height pile ratio (terry ratio) type of terry yarn count yarn crimp fabric thickness yarn density and fiber density. Cotton terry woven fabrics were produced with different parameters namely pile height picks per cm and weft yarn count their porosity was determined by measuring fabric density and fiber density and compared with the theoretical porosity. The validity of the theoretical model was confirmed by experimental results. Experiments show that this model gives good results.

In this study, oxygen and nitrogen plasma treatment was carried out on wool fabrics during 5, 10 and 15 minutes at low (LF) (40 kHz) and radio (RF) (13.59 MHz) frequency. Then the effect of plasma treatment on tear strength, contact angle, whiteness and yellowness index of wool fabrics was investigated. In addition, the hydrophility of plasma treated samples was analyzed after the washing. The physical and chemical properties of wool fabrics treated with oxygen and nitrogen plasma were characterized by scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). According to the results, nitrogen plasma treatment improved the tear strength of samples. Furthermore, plasma treatment increased the yellowness of samples while decreasing the whiteness index of samples. The hydrophility of samples decreases with plasma treatment and with the increase in plasma treatment time. Moreover, SEM results showed that the plasma treatment caused to occur deformations on the surfaces. Lastly, EDX results showed that the amount of oxygen and nitrogen increased in the surfaces after oxygen and nitrogen plasma treatment.

Environmental issues have received increasing attention recently. Compared to solvent borne polyurethane (PU), waterborne PU requires relatively little solvent dosage. Therefore, waterborne PU is used to replace traditional solvent borne PU to satisfy environmental and economic requirements. Chitosan is a material that has been discussed widely in recent years because of its exceptional antimicrobial performance, biocompatibility, bioactivity, and biodegradability. This study primarily uses a prepolymer mixing process to synthesize m-TMXDI based waterborne PU with different ratios of aqueous chitosan and chain extenders (ethylenediamine; EDA). Modification reactions are conducted and waterborne PU modified by aqueous chitosan is synthesized. Through this experimental method, emulsions modified by different compositional proportions of aqueous chitosan to EDA were tested. For material determination, FTIR, NMR, and XPS were used to conduct chemical structure determination and GPC molecular weight tests. Regarding membrane properties, a contact angle meter analyzed the hydrophility of the membrane and the antimicrobial performance of the prepared waterborne PU membrane against Staphylococcus aureus and Escherichia coli. The test results showed the following characteristics: (1) The terminal NCO group of the waterborne PU (WPU) was bonded with the terminal amino group(-NH2) of chitosan, and (2) as the proportion of aqueous chitosan added increased, improvements were observed regarding molecular weight, hydrophility, and antimicrobial performance.