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Moisture transmission through textiles. Part II: Evaluation methods and mathematical modelling

Das B., Das A., Kothari V. K., Fanguiero R., Araújo M.

Autex Research Journal

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2007

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Vol. 7, no. 3

194--216

EN

The moisture transmission behaviour of a clothing assembly plays a very important role in influencing its efficiency with respect to thermophysiological body comfort. This paper is in two parts. Part I deals with the processes involved in moisture transmission and the factors at play. Part II is concerned with selecting the measurement techniques which are of great importance in determining fabric factors that influence comfort. The instruments and methods used for testing purposes should adequately simulate the exact conditions for which the fabric will be used, in order to determine the effectiveness of that fabric for a particular wearing situation and environmental condition. The testing methods used and the apparatus developed by different researchers for determining moisture transmission through textiles by different mechanisms are discussed in this paper. Moreover, this part of the paper deals with the mathematical models of liquid and vapour transport through textile materials developed by several scientists in order to understand the exact phenomena involved and to predict the factors affecting the transmission under a particular condition.

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Moisture transmission through textiles. Part I: Processes involved in moisture transmission and the factors at play

Das B., Das A., Kothari V. K., Fanguiero R., Araújo M.

Autex Research Journal

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2007

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Vol. 7, no. 2

100--110

EN

Moisture transmission through textiles has a great influence on the thermo-physiological comfort of the human body which is maintained by perspiring both in vapour and liquid form. The clothing to be worn should allow this perspiration to be transferred to the atmosphere in order to maintaining the thermal balance of the body. Diffusion, absorption-desorption and convection of vapour perspiration along with wetting and wicking of liquid perspiration play a significant role in maintaining thermo-physiological comfort. The scientific understanding of the processes involved in moisture transmission through textiles and the factors affecting these processes are important to designing fabrics and clothing assemblies with efficient moisture transfer in different environment and workload conditions. This paper is in two parts.Part I focuses on the moisture transmission through textile materials and it discusses the processes involved in moisture transmission and the key influencing factors at play to maintaining comfort. It is underlined that the processes which play the major role in moisture transmission in a particular situation are dependant on the moisture content of the fabric, the type of material used, the perspiration rate and the atmospheric conditions, such as humidity, temperature and wind speed. Part II is concerned with the selection of the measurement techniques which are of great importance in determining fabric factors that influence comfort. The instruments and methods used for testing purposes should adequately simulate the exact conditions for which the fabric will be used, in order to determine the effectiveness of that fabric for a particular wearing situation and environmental condition. The testing methods used and the apparatus developed by different researchers for determining moisture transmission through textiles by different mechanisms are discussed in this paper. Moreover, this part of the paper deals with the mathematical models of liquid and vapour transport through textile materials developed by several scientists in order to understand the exact phenomena involved and to predict the factors affecting the transmission under a particular condition. When designing the comfort of a clothing product for a particular application, the requirements may result from needs concerning the application, the individual wearer and the environmental conditions.

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Reducing yarn hairiness in winding by means of jets: optimisation of jet parameters, yarn linear density and winding speed

Rengasamy R. S., Kothari V. K., Patnaik A., Ghosh A., Punekar H.

Autex Research Journal

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2005

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Vol. 5, no. 3

127--132

EN

Reducing yarn hairiness during yarn winding by the use of air jets is a new approach, since the production rate of winding is very high and the process itself increases yarn hairiness. The Box & Behnken factorial design approach has been used to optimise the jet angle, the jet diameter, yarn linear density and the winding speed in order to reduce the yarn hairiness. A jet angle of 450, a jet diameter of 2.2 mm, 10 tex yarn and a winding speed of 800 m/min give the optimal results in terms of reducing the hairiness. A CFD (computational fluid dynamics) model has been developed to simulate the airflow pattern inside the jets with the use of Fluent 6.1 software. The air velocity around the core of the jet is the influencing factor in wrapping the hairs on the yarn body.

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A study on frictional characteristics of woven fabrics

Das A., Kothari V. K., Vandana N.

Autex Research Journal

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2005

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Vol. 5, no. 3

133--140

EN

We have examined the fabric-to-metal surface and fabric-to-fabric frictional characteristics (in both warp and weft directions) of a series of fabrics containing 100% polyester, 100% viscose, and P/C & P/V blends with different blend proportions. It has been observed that the normal load and the frictional force follow a logarithmic relationship for all the fabrics. The nature of fabric friction is characterised by different parameters such as the F/N ratio, and the values of n, k and k/n. Fabric-to-metal friction is found to be less sensitive to fabric morphology and rubbing direction, whereas fabric-to-fabric friction is highly sensitive to these factors. Fabric friction has been affected by many factors such as the type of fibre, type of blend, blend proportion, yarn structure, fabric structure, crimp and crimp height, compressibility, etc. In P/C and P/V blended fabrics, the frictional force increases as the cellulose fibre component increases.