1401 通気量の異なる生地を巻きつけた楕円柱の流れ場特性

As the global temperature increases over time due to different environmental pollutions, apparel clothing with excellent thermo-physiological comfort needs to be developed to improve human health and comfort. Thermo-physiological comfort of apparel clothing must be suitable for the wearer both in winter and summer seasons. Poor thermo-physiological properties can lead to discomfort, fluctuation in body temperature, poor sweat management during wear and can affect human health as well as work efficiency. For this reason, optimum thermo-physiological comfort of clothing is a prerequisite for users at any given weather. The aim of this study was to investigate the effect of cotton yarn parameters on thermo-physiological comfort of woven fabrics. Four types of woven fabrics were developed from cotton yarn with different counts, twist, coefficient of variation of mass (CVm), neps, hairiness, thin places, thick places, strength and elongation. Yarn samples were produced separately by carding and rotor spun before they were woven on an air jet machine with same settings. Finally, the woven fabrics were finished in a combined finishing treatment process. Thermal resistance, thermal conductivity, thermal absorptivity, thermal diffusivity, air permeability and relative water vapor permeability of the woven fabrics were measured and analyzed. Statistically analyzed results showed that thermal resistance, thermal conductivity, thermal absorptivity and air permeability of fabrics had statistically significant change with P-values of .029, .035, .005 and .000, respectively. However, from the results, the yarn parameters did not affect thermal diffusivity and water vapor permeability of fabrics. Model equations were developed based on the results to predict the comfort of the fabric from the yarn parameters.

The aim of our work was to establish whether very good to excellent UV (ultraviolet) protective properties of fabrics can be obtained through a suitable fabric construction and yarn colour, at the same time ensuring suitable air permeability. For this purpose, six different fabric structures divided into three groups were employed. The samples were made in blue and red combinations of weft with different sequences and proportions between the upper and lower weave threads. A comparison of different fabric structures and colours was attempted to enable the assessment of the impact of the mentioned parameters on both, UV protective properties and air permeability of fabrics. The analysis comprised the investigation of physical and permeability properties, as well as the colour measurements on twelve different cotton fabrics. The research indicated excellent UV protection (>60) in all samples. UV protection depended on their construction and in a sufficiently closed structure, also on the colour of the used yarn. There was no significant difference between the samples in blue and red. In addition to excellent UV protection, four samples (one double-weft and three double fabrics) also demonstrated very high air permeability, which was 3–5 times higher than in the one-layer sample, which demonstrated the best UV protective properties. The research has shown that fabrics with a very high ultraviolet protective factor value and good air permeability can be made by using a suitable construction and yarn colours that sufficiently absorb UV light; the latter being particularly important for light summer cotton clothes.

Functionality of technical textiles and apparels in a wide spectrum of end-uses is intensely dominated by their air permeability, which in turn depends on fabric porosity and structure. This work aims to investigate air permeability of warp-knitted fabrics using experimental and numerical simulation methods. Samples of locknit, three-needle satin and four-needle satin two-bar warp-knitted fabrics at tight, medium and loose densities together with single-bar 1×1 and 2×1 warp-knitted fabrics were knitted. The effect of loop density, underlap length and fabric structure on air permeability was investigated. The 3D geometry of locknit and single-bar 1×1 and 2×1 warp-knitted fabrics was modeled using CATIA. The structural geometry of a knitted loop as the unit cell of warp-knitted fabrics was simulated based on Vassiliadis model. The geometry models then were coupled with a computational fluid dynamics (CFD) model for flow simulation. Fluid flow through the fabric structure was simulated by numerically solving incompressible creeping Newtonian flow through the pore space of generated knitted structures using Fluent. The results were then compared with experimental data. It was found that 1×1 single-bar fabrics have higher air permeability than 2×1 single-bar fabrics. It was also found that single-bar fabrics show significantly higher air permeability compared to two-bar warp-knitted fabrics. For the two-bar fabrics, the results point to higher air permeability of locknit fabrics, followed by three-needle satin and four-needle satin. The results also indicated that increase in underlap length and loop density leads to reduction of both pore size and fabric porosity and therefore decreasing air permeability. It was found that the experimental and numerical results are acceptability compatible with error of less than 16 %. It was concluded that the proposed model is potentially capable of prediction of air permeability of single-bar and two-bar warp-knitted fabrics.

The number of filaments in yarn cross-section, weave density, and weave type are considered the most important factors that affect the property of air permeability of multifilament woven fabrics. Microfilament yarns significantly affect the air permeability property of this type of fabric because of the low porosity between the filaments. This study deals with the development of a fuzzy logic model for predicting the air permeability of multifilament polyester woven fabrics produced from conventional and microfilament yarns. The polyester multifilament yarns used in this study were produced with three different microfilament fineness and two conventional filament fineness levels. The woven fabric samples used in this study were obtained in three weave types: plain, twill, and satin, and with five different weave densities. In accordance with the experimental test results, both regression analysis and fuzzy logic system were built. The air permeability results generated from the developed fuzzy model and the regression equations were compared with the experimental values. Satisfactory and accurate prediction results were obtained with the developed fuzzy logic model. The mean absolute error of the fuzzy model and regression analysis were found to be 2.32%, 12.59%, respectively. Therefore, it was confirmed that the fuzzy model was superior in predicting air permeability.

PurposeThe purpose of this research was to find the influence of sublimation process on air permeability and water absorption dynamics of knitted and woven polyester-based fabrics.Design/methodology/approachThree different sublimation designs were prepared and applied (keeping the same sublimation parameters) for eight variants of knitted and four variants of woven polyester-based fabrics. Air permeability and water absorption dynamics during 180s period was measured and compared before and after the sublimation process.FindingsAccording to the obtained results, high temperature and pressure applied in sublimation process have influence on the porosity and air permeability of knitted fabrics; however, the influence on water absorption dynamics is minimal. Sublimation design dos not have any influence on the mentioned properties.Originality/valueThe obtained results of the sublimation process influence on air permeability and water absorption dynamics of knitted and woven polyester-based fabrics will help to understand how sublimation process can affect comfort properties of textile fabrics.

In this article, porosity and air permeability of denim fabric produced from filament core-spun yarns with different filament fineness and yarn linear density were demonstrated. For this purpose, 110 dtex drawn textured polyester filaments with conventional, fine, and micro finenesses were used as core part, and combed cotton fiber was used as sheath part to obtain core-spun yarns with four different yarn linear density on a modified ring spinning system with the same spinning parameters. Besides the production of core-spun yarns, 100% cotton ring-spun yarns were produced as control group at the same conditions for each yarn linear density, as well. To evaluate the effect of filament fineness and yarn linear density on air permeability and total porosity, denim fabrics were obtained by using 24 yarn samples as weft at the same cover factor with four determined weft densities. Results showed that filament fineness and yarn linear density have a significant effect on total porosity and air permeability at a significance level of 0.05. In addition, high correlation (79.4%) between air permeability and total porosity of denim fabric samples was observed at a significance level of 0.01.

In this work, single jersey fabrics were produced with different yarn numbers and loop lengths by means of conventional ring‐spun and compact ring yarns. Knitted fabrics were subjected to two different relaxation treatments, dry and washing. After relaxation, air permeability of cotton‐knitted fabrics with different yarn numbers and loop lengths were determined. In addition, wales per centimeter, courses per centimeter, thickness, and weight of fabric were tested. According to the test results, relaxation type and some fabric structural parameters affected air permeability of single jersey fabrics. Following the washing relaxation, it was found that knitted fabrics became tighter, their weight and thickness were higher, while their air permeability was lower.

The fact that weft knitted fabrics has a stretchable, 3D, porous and interlocking structure makes them unique when manufactured from high performance fibers. Knitted fabrics with different architectures exhibit different properties. Different loop forms like tuck and skip stitches with various loop lengths reveal different physical and mechanical properties. Literature review indicated that wisely arrangement of tuck stitches within the pattern repeat alter the weft-knitted fabric structure from natural and synthetic fibers. Therefore, we studied the effect of number and location of tuck stiches on air permeability of weft-knitted fabrics from glass yarn. Single-bed, flat weft knitting machine was used to knit fabrics with different architectures from three-ply glass yarn. The nominal single-end count of used E-glass yarn was 136 tex. It is anticipated that the number and location of tuck stitches within knit pattern effect physical and air permeability properties of weft-knitted fabrics from glass yarn.

Air permeability of multilayer nonwoven fabrics obtained by combining needle punched webs made from fibers with different linear mass densities is investigated. The optimal composition of nonwoven webs providing multilayer fabrics with increased permeability is determined. A model linking the air permeability of multilayer fabrics with their thickness, which depends on the number of layered webs, is proposed. The air filtration mechanism in webs and multilayer fabrics is substantiated. The process of structural formation of the webs and multilayer fabrics is considered. The influence of the structure of the webs and multilayer fabrics on their air permeability is determined.

The paper presents an approach to model the behaviour of a representative volume design elements of pile warp woven fabrics. With the internal geometry of the built, the model computes overall parameters of the deformed pile warp woven fabrics, such as fibre volume fraction, porosity etc. The internal geometry is visualised and such properties as pore structure in typical cross-sections are analysed. The internal geometry description is further fed into flow modelling software, which allow computing local permeability and mechanical properties of the deformed the Loop of pile warp woven fabrics. This study aims at the structure of the geometrical characteristics of a warp pile woven fabrics structure by using the basic fabric parameters to find a suitable model that makes possible the prediction of weavability limited and suitable for their performance, and the evaluation of a three-dimensional plain pile warp woven fabrics geometrical model. Dimensional plain pile warp woven fabrics geometrical model. Loop lengths, realistic models based on a better approach of geometry and material properties will be created in order to investigate the numerical analysis performance of the performance properties of pile warp woven fabrics. Porosity, air permeability of a woven fabric on the base of its constructional parameters. Of the warp pile woven fabrics structure via module. As the constructional parameters of a woven fabric are considered: maximum and suitable setts of warp and weft yarns, diameters (or fineness) of warp and weft yarns and a type of weave. This research is focused on cloth warp pile woven fabrics structure of warp cotton and several types of weft. The evaluations of the geometrical model for three level of loop length (height, medium, low) are carried out by three methods of weft density. based on the comparison of the measured warp pile loop length of existing warp pile woven fabrics structure fabrics with the calculated values that result from the geometrical model. And controlled of the shape of the warp pile loop that result from the air permeability , thickness, porosity, test of the fabrics with the air permeability, thickness, porosity curves that are received from the simulation of the analysis. A correlation between calculated values of structural parameters and experimental; The suggested process makes possible prediction of ideal sett of weft for terry woven fabric in three densities (18) wefts with the rest of possible properties throw porosity and value of air permeability, wick-up of pile warp woven fabrics, to the materials types of weft which are: cotton, polyester, blended (cotton/polyester (50/50)) viscose rayon, which are characterised by their constructional parameters as are sett of piles warp and ground yarns, by diameters or fineness of cotton materials and by the plain of weave Keywords: weavability limited, geometrical pile fabric, permeability, porosity. geometrical Models,

To determine the flight of a ski jumper it is essential to know what aerodynamic forces are acting on the ski jumper. However, few data on this are available, especially for a V-style ski jumping flight. We have measured the aerodynamic forces during the free flight phase for a V-style, as well as a parallel-style, ski jump by employing a full-size model in a wind tunnel. The aerodynamic force data, (drag, lift and pitching moment) were obtained to create an aerodynamic database. These forces are given in polynomial form as functions of the angle of attack, the body-ski (forward leaning) angle and the ski-opening (V-style) angle. Using the polynomial form database is a convenient way of obtaining the aerodynamic forces. Moreover, the wind tunnel was equipped with a ground effect plate to measure the aerodynamic forces during the landing phase. It was found that the difference between the lift with and without the ground effect plate increases with the ski-opening angle. The longitudinal stability in the pitching motion of a body-ski combination is also discussed on the basis of the pitching moment data. This indicates that a stable pitching oscillation of the body-ski combination may arise around an equilibrium point in the angle of attack, the trim angle of attack, during flight.

The main goal of this research was to determine the influence of the inner layer thickness and tightness, which depends on the length of the float determined by the float step and number of floats in the pattern repeat, on the thermal insulation and air permeability of the multilayered weft-knitted fabric. For this reason, weft-knitted spacer fabrics were produced by using woolen yarns for the outer layers and polyester filament yarn for the inner layer, with the number of floats in the inner layer varying between two and 20. Results from this research showed that the consequent increase in thickness and tightness of the spacer fabric’s inner layer has unequal effect on the thermal insulation and air permeability. Therefore, similar thermal insulation can be achieved by having significantly higher air permeability. This is especially evident over a long period of time.

Texturized yarns are often preferred especially in home textiles and sportswear. To improve polyester filament properties, mechanical, thermal, chemical and combinations of texturing processes are applied. With these processes, filament yarns take on a curved and voluminous structure and gain a permanent form. Properties of the texturized yarn can be varied as raw materials properties, machine type and process factors. This study covers the investigation of the effect of cross-sectional shape of fiber (round and trilobal) and texturing process temperature (150, 175 and 200 0C) on air permeability of false twist textured polyester single jersey knitted fabrics. Results showed that the highest air permeability value was obtained from knitted fabric with round fiber cross-sectional shape polyester filament textured at 150 0C. According to the statistical analysis, both the fiber cross-sectional shape and process temperature were found to have a significant effect on air permeability property.

A novel antibacterial agent polysulfopropylbetaine (PSPB) bearing carboxyl groups was synthesized and its application on cotton fabric to provide durable antibacterial property was also presented. The successful synthesis of PSPB and its immobilization onto the cotton fabric surface were verified by a series of tests including FTIR, 1H NMR, XPS and SEM. Viable cell counting method was employed to investigate antibacterial properties of the finished cotton fabrics. It was found that the cotton fabrics treated with PSPB were endowed with desirable antibacterial activity against both gram-negative bacteria Esherichia coli (E.coli, AATCC 6538) and gram-positive bacteria Staphylococcus aureus (S.aureus, AATCC 25922), with the bacterisotatic rates of 99.69 % and 99.95 %, respectively. Notably, the bacterial reduction rates still maintained over 90 % against both bacteria even after 50 consecutive laundering cycles. Moreover, tests concerning the hydrophilicity, air permeability, water vapor transmission, mechanical properties as well as thermal properties were carried out systematically. The experimental results indicated the hydrophilic performance, air permeability and moisture penetrability of the cotton fabrics finished with PSPB were improved greatly in spite of a slight reduction in thermal performance and little obvious influence on mechanical performance. The antibacterial cotton fabric has the potential to be applied in sportswear, underwear, household textiles, medical fields and much more.

The water vapor and air permeability properties of fabrics are the determining factors for thermal comfort. It is stated in the literature that the hygroscopic structure of wool fibre and the fibre surface properties improve the water vapor permeability property, thus increasing the sense of comfort. In this study water vapor and air permeability of 16 woollen fabric were investigated. It was shown that the effect of finishing process, weave type and raw material on air permeability is significant. In case of water vapor permeability, the effect of finishing process and weave type was found to be significant in the 95% confidence interval, while the effect of raw material was not found to be significant. Furthermore, permeability properties of woollen fabrics were predicted both multiple linear regression and artificial neural network. The R2 values of the models were 0.989 and 0.485 obtained with multiple linear regression and 0.988 and 0.773 obtained with artificial neural network, for air and water vapor permeability, respectively. Results of the artificial neural network were quite good especially for water vapor permeability.