Moisture Transfer Properties Research Articles

Thermal Properties of Towelling Fabrics

To obtain guideline for developing new types of clothing used the towelling fabrics, we clarified the heat and moisture transfer properties of the towelling fabrics. The results obtained were as follows:1. Because the towelling fabrics were thick, the dry heat loss Hd of the towelling fabrics was lower than that of cotton fabrics on the market. However, the measured value Hd of the towelling fabrics was higher than that predicted from their thickness and apparent density.2. The thermal conductance Cd of towelling fabrics which were made of cotton fiber was higher than other fibers (except for cotton) in dry or wet conditions. From this fact, it was suggested that using fabrics which were made of other fibers (except for cotton) for clothing for winter was valid, because their Cd was lower than that of cotton.3. The maximum value of heat flux qmax of the towelling fabrics was about half of that of cotton fabrics on the market. Furthermore, it was found that qmax conformed to uses could be controlled by patterning the pile.4. The thicker the fabric's thickness was, the lower the latent heat loss Hw became. And, it was suggested that the body temperature under the sweating with towelling clothing would not decrease rapidly, because the water absorption area in the ground layer was larger than those in the upper and lower pile layers. From these results, it was concluded that applying the towelling fabrics to clothing for infants or elderly persons was to be desirable.

From fabric hand to thermal comfort: the evolving role of objective measurements in explaining human comfort response to textiles

This paper traces the evolution of objective measurement of textile hand and comfort from Pierce through modern methodology and approaches. Special emphasis is given to discuss the contribution of the Kawabata Evaluation System (KES) towards advancing the state of objective measurement. Laboratory case studies are used to show how data generated by the KES and other instruments can be integrated into a comprehensive approach that attempts to explain human comfort response to garment wear in terms of fabric mechanical, surface and heat and moisture transfer properties.

Effect of addition of polyethylene glycol on the moisture transfer and waterproof properties of foam-finished nylon fabrics

The effects of the addition of polyethylene glycol (PEG) within the coated film on the water vapor permeability and waterproof properties of the foam-coated fabrics were investigated. Foaming solutions added with PEG had lower surface tension than those without, and the viscosity and stability of the foaming solution varied with PEG of different molecular weight. When PEG is of 1,000 daltons (PEG 1000), the viscosity and stability of the foaming solution was the highest among molecular weights ranging from 400 to 16,000, whereas the surface tension was the lowest. The stability would rise proportionally with viscosity if the viscosity of the foaming solution is between 13,610 cps and 13,960 cps. When PEG 1000 was added, the particle size of the foaming solution was smaller, followed by PEG 600. But when PEG 4000 or ethylene glycol (EG) was added, the particle size was bigger. The introduction of PEG 1000 to the foaming solution produced better water vapor permeability and waterproof properties. Fabrics coated with foaming solution, to which PEG 1000 was added, had smaller and more micropores in the coated film. Coated film without the addition of PEG had less micropores, and that with the addition of EG or PEG 4000 had large pores with non-homogenous pore sizes. These results were confirmed by SEM observation.

Studies on Moisture Transfer and Waterproof Properties of Foam-Finished Nylon Fabrics (Part 2). Effects of Foaming Methods on Moisture Transfer and Waterproof Properties of Foam-Finished Nylon Fabrics.

Water vapor permeabilities and waterproof properties of nylon fabrics obtained by foam-coating processes were studied and the influences of foaming methods on the permeabilities and waterproof properties of the coated fabrics were investigated. For the same weight of coated resin film. the water vapor permeability and water resistance of the foam-coated fabrics were far better than those of conventional nonfoam-coated fabrics. Foam-coated fabrics obtained by the foam-mixer method showed the best water vapor permeability and water resistance. the homomixer foaming method was the second and the stirrer foaming method was the third. In the homomixer foaming method. the water vapor permeability and water resistance of foam-coated fabrics showed the best result when the foaming time was 10min or longer and the rotation speed was 4500rpm (rotation energy, 383J/g solution). In the foam-mixer foaming method, the water vapor permeability and water resistance of the foam-coated fabrics were better than those observed for the homomixer foaming method when the foam blow ratio exceeded 4 and the mixing head speed exceeded 700rpm (rotation energy, 12.6J/g solution). The water vapor permeability and water resistance were found to be dependent upon the size distribution of the foam particles. For both homomixer and foam-mixer methods, small and homogeneous foam particles were obtained at higher foaming speeds, longer foaming times and higher blow ratios. and hence higher water vapor permeability and water resistance could be obtained. These results were confirmed by the SEM observation.

Evaluation of heat and moisture transfer properties in a frozen-unfrozen water-soil system

An experimental study of heat and mass transfer in a moist unsaturated sand has been carried out by maintaining the two ends of a sample column at temperatures of −5 and 30°C, respectively. Measurements of temperature have been made as a function of distance from the cold end and time, along with effective thermal conductivity and liquid water distribution at the end of the experiment. Comparison of the measured thermal conductivity values shows close agreement with calculated values from an effective continuous model (Singh et al..). Evaluation of thermal and moisture diffusion coefficients has been done from measured steady-state temperature and moisture profiles. A dryout condition has also been determined from the evaluation of heat and moisture transfer properties.

The effect of protein isolate of Pistacia terebinthus L. on moisture transfer properties of cellulose-based edible films

Protein isolate prepared from Pistacia terebinthus L was added in different amounts to edible films of (hydroxypropyl) methylcellulose having polyethylene glycol 400 as plasticizer. Water vapour transmission of cellulose-based films with protein added were measured as a function of time. A steady rate was achieved at the end of day 7. Moisture permeabilities of films were determined using steady rates. It was found that permeability values increase with increasing protein content of the films. This trend was explained in terms of the amino acid composition of the protein isolate.

Microwave heating of baked dough products with simultaneous heat and moisture transfer

By using the Crank-Nicolson finite-difference method, a computer model to predict temperatures and moisture contents during microwave heating was developed. In this model, variable thermal and moisture-transfer properties were allowed. The model could apply to microwave heating with continuous and on-off power and to the cooling stage after microwave heating. A method to estimate the electric-field strength of a microwave oven was outlined and verified experimentally. Bread was chosen as the test material. The model predicted temperatures very well during microwave heating and the cooling stage. It also predicted the average moisture content closely to experimental values up to 30 seconds of heating (within 2% error) with an electric-field strength of 42·5 V/cm.

Improved Measuring Method for Heat and Moisture Transfer Properties of Fabrics by Injecting Water to a Simulated Skin

Improved Measuring Method for Heat and Moisture Transfer Properties of Fabrics by Injecting Water to a Simulated Skin

Effect of Exercise Garment Fabric and Environment on Cutaneous Conditions of Human Subjects

The role of three experimental knitfabrics and two environmental conditions on human subjects' stratum corneum water content, rate of water evaporation from their skin surface, rate of capillary blood flow, and skin temperature are reported Exercise garments constructed from 1. 5 denier polyester, 3.5 denierpolyester, or 100 % combed cottonfabrics were worn by each subject while exercising and resting in a hot, humid and a hot, dry environment. The noninvasive cutaneous measurements were taken on the subjects' upper back using an Evaporimeter, a laser Doppler velocimetry instrument, a microwave probe, and a thermistor. Kawabata instrumentation was used to determine shear, bending, tensile, and compression, as well as surface features, of the three knit fabrics. Heat and moisture transfer properties of the fabrics were analyzed over a wide range of environmental conditions using the Kawabata Thermolabo. Rate of skin evaporative water loss was slower in the higher humidity environment. More water accumulated in the subjects' stratum corneum when they exercised in the humid environment. Capillary bloodflow was not significantly influenced by environment. Skin temperatures statistically differed in the two environments, but differences were negligible. In selecting loose fitting garments to be worn in hot environments, greater consideration should be given to openness of the fabric structure than to the fiber content. When garments fit the body snugly, fiber content may be of more critical importance in maintaining comfort.

MOISTURE TRANSFER PROPERTIES of WILD RICE

ABSTRACTWorking isotherms for processed wild rice and desorption isotherms for unprocessed wild rice were determined at temperatures ranging from 10 to 43.5°C. the constants for the Guggenheim‐Anderson‐DeBoer (GAB), Day and Nelson, Chen and Clayton and modified Halsey equations were determined by using a nonlinear optimization technique. the GAB equation showed extremely good fit to the experimental data (less than 5% error). the diffusion coefficients for moisture transport in both broken and whole processed wild rice and for unprocessed wild rice samples were determined at room temperature. the processed broken wild rice kernels had an effective diffusion coefficient of 2.66 × 10−9 m2/h, whereas the effective diffusion coefficient was 7.08 × 10−10m2/h for the processed whole wild rice kernels. Unprocessed wild rice had moderate effective diffusivity (1.4 × 10−9 m2/h). These results predicted quite well the equilibrium water activities and time to equilibrium of wild rice‐white rice mixtures using both analytical methods and the finite element method. the transfer of moisture to or from packaged wild rice was also illustrated for different distribution systems.

The Transfer Properties of Moisture and Heat Through Clothing Materials

The Transfer Properties of Moisture and Heat Through Clothing Materials

Moisture Transfer Properties of Dry and Semimoist Foods

ABSTRACTEquilibrium moisture content, mass diffusion coefficients, and densities were collected for wheat flour, shredded wheat, raisins, nonfat dry milk, and freeze‐dried apple, turnip, and ground beef at 25 ± 1°C. Flour adsorbing to 0.75 aw had the largest mass diffusion co‐efficient, 1.15 × 10−7 m2/hr and raisins had the smallest value of 0.015 × 10‐7 m2/hr. Two of the food uroducts. flour desorbing to 0.11 aw, and the freeze‐dried turnip, exhibited diffusion coeffcients which were dependent on the moisture content. Most of the foods reached equilibrium within 1 wk based on an objective criterion of no more than a 0.5% dry basis moisture difference over three successive readings at 1 wk interval.

The Transfer Properties of Moisture and Heat Through Clothing Materials

The Transfer Properties of Moisture and Heat Through Clothing Materials

The Transfer Properties of Moisture and Heat through Clothing Materials

The wear trials of underwears were performed in a climatic chamber at 10°Cand 25°C. Relations were studied between the temperature and humidity within clothing, the surface temperature of clothing and the residual sweat content of clothing, and wear sensations. A correlation has been investigated between the test results on the simulator and those by the wear trials. The results are summarized as follow : (1) The temperature and humidity within clothing, the surface teperature of clothing and the residual sweat content of clothing on the wear trials are related to the wear sensations that are influenced by the microclimate within clothing.(2) The variation of the temperature and humidity within clothing on the simulator is similar to those on the wear trials.(3) The significant correlation was not found between the wear sensations on the wear trials and the moisture regain, water absorption property and clo value of clothing materials.

The Transfer Properties of Moisture and Heat through Clothing Materials

The Transfer Properties of Moisture and Heat through Clothing Materials

The Transfer Properties of Moisture and Heat through Clothing Materials

The Transfer Properties of Moisture and Heat through Clothing Materials

The Transfer Properties of Moisture and Heat Through Clothing Materials

A correlation has been investigated between the test results on the simulator and those by the field test. In the study the microclimate within clothings has been analyzed. The experimental results of women's pajamas are summarized as follows :(1) The wear comfort of women's pajamas is expressed by the subjective estimations of the softness and dryness.The softer and drier, the more comfortable.(2) The residual water content of pajamas and the residual water content on the skin of the simulator highly correlates with the humidity within clothing on the simulator.(3) The wear comfort on the field tests can be explained by the residual water content on the simulated skin, the surface friction and the bending force of fabrics.

The Transfer Properties of Moisture and Heat through Clothing Materials

The Transfer Properties of Moisture and Heat through Clothing Materials