Search results

To clarify the principles and mechanisms of water vapour transfer by diffusion in waterproof breathable fabrics for clothing, experiments using a simple glass dish were carried out under steady state conditions with and without a temperature gradient in the climatic chamber. It was found that both vapour pressure and natural convection within the air gap affect water vapour transfer. The rates of water vapour transfer are ranked microfibre fabrics, cotton ventiles, PTFE‐laminated fabrics, poromeric polyurethane laminated fabrics, hydrophilic laminated fabrics, and polyurethane‐coated fabrics. In the presence of a temperature gradient, condensation was also found to be a major factor, especially at air temperatures below 0°C. Condensation occurred the least on the inner surface of PTFE‐laminated fabrics followed by cotton ventiles, microfibre fabrics, hydrophilic‐laminated fabrics, poromeric polyurethane‐laminated fabrics, and polyurethane coated fabrics.

Nowadays, green cutting has become the focus because of its ecological problem and the necessary environment protection, so that the research on experimentation of green cutting with water vapor as coolant and lubricant is studied because water vapor has many benefits of cheapness, no pollution, no harm and no recycling and handling.

The vapor generator and the vapor feed system are manufactured, the distribution of temperature and velocity of vapor jet flow are simulated by MATLAB program, and under the conditions of compress air, oil water emulsion, water vapor as coolant and lubricant and dry cutting, respectively, the turning experimentation of comparison which the tool is YT15, and the working material is steel 45.

Water vapor, as coolant and lubricant, the cutting force is reduced, respectively about 30‐40, 20‐30 and 10‐15 percent by comparing to dry cutting, compressed air and oil water emulsion. The cutting temperature is, respectively about 30, 40 and 50 percent with the other conditions of dry cutting, compressed air and oil water emulsion. The friction coefficient and the chip deformation coefficient are correspondingly decreased and the surface roughness value has been diminished too. Through analysis of the experimental results, water vapor as coolant and lubricant possesses better lubricating action because of the excellent penetration performance and the low lubrication layer shearing strength of water vapor.

Water vapor as coolant and lubricant provides a novel method for realizing no contamination green cutting.

Investigates whether water vapour transfer from the local environment of the human body at a relative humidity less than 100 per cent to a rainy or wind‐driven environment of relative humidity almost 100 per cent is possible. To identify whether prolonged rain has an effect on water vapour transfer in waterproof breathable fabrics, secondary experiments were carried out using a precipitator simulator covering a large area with severe rain. It was found that waterproof breathable fabrics breathe even under rainy conditions (with lower water vapour transfer rate), though encountering limitations under prolonged severe rain. The water vapour transfer rate was reduced under wind‐driven rainy conditions. More condensation was observed under rainy conditions on all fabrics except PTFE laminated fabrics.

The purpose of this paper is to develop water vapour as a new cooling and lubricating technique in drilling Ti6Al4V. Water vapor is an economical and eco‐friendly coolant and lubricant. However, it is necessary to study the drilling chip deformation, forces and drilling temperature when drilling Ti6Al4V using this new green drilling technology, which meets the development trend of green machining technology.

Comparative experiments are carried out with HSS drill bits and YG6X (K10 type in ISO) cemented carbide drill bits in drilling Ti6Al4V under the conditions of oil water emulsion, water vapor as coolant and lubricant and dry drilling, respectively. The drilling forces, temperature and drill bit wear VBmax have been examined and analyzed. Further, a new type practical drilling quick‐stop device is developed for studying the chip deformation in drilling Ti6Al4V. The drilling forces distribution test in drilling Ti6Al4V is also developed.

When water vapor is used as coolant and lubricant, the torque is reduced by 15‐25%, 5‐10% in comparison with dry drilling and oil water emulsion, respectively; the thrust is reduced by 5‐10%, 4‐5%; the temperature is reduced by 15‐20%, 5‐8% and the wear VBmax of drill bit is reduced by 60‐80%, 10‐15%, correspondingly. Also, the contact length in chip‐tool interface decreases and the drilling deformation is reduced. The coolant and lubricant conditions and feed rate have little impact on the drilling force distribution in drill bit cutting edges.

A green machining technology, water vapor used as coolant and lubricant, is used in drilling Ti6Al4V; it can reduce drilling deformation, drilling forces, temperature and flank wear. A new drilling quick‐stop device is devised to obtain the drilling chip roots. Also, the drilling force distribution test was developed for obtaining the rate of drilling forces in cutting edges when drilling Ti6Al4V.

Unlike other materials, textiles associate with aesthetic and mechanical properties such as flexibility and removability that allow them to be deployed or folded as required and which make them good candidates for clothing and furnishing but also, eventually, for other applications such as building. Actually, the clothing should ensure appropriate heat and mass transfers between the human body and its environment in order to maintain the thermo-physiological comfort. For that, it is important to determine water vapor permeability (WVP) of textile. Several normalized procedures with variants depending on the nature of the tested material exist to measure the WVP. One of the methods used is the “dish method” described by the British Standard (BS 7209). The purpose of this paper is to determine the influence of the test parameters on the WVP measurements.

Consequently, WVP of different textiles was measured while varying several parameters like: nature of fabrics, air layer thickness, vapor pressure gradient and air velocity.

A decrease in the WVP values was observed with an increase in the air layer thickness and the number of textile layers. On the other side, an increase in the water pressure gradient induces an increase in the WVP value. Finally, it was also observed that air velocity has an impact on the WVP measurements.

In addition to intrinsic properties of fabrics, i.e., nature of fiber, woven structure, the influence of the several extrinsic properties, i.e., the influence of the air layer thickness, the number of textile layers, the vapor pressure gradient and the air velocity, on the WVP were investigated. Some researchers have already investigated the impact of these parameters on the WVP measurement separately. However, this study presents a difference from other studies that it takes into account the influence of the both intrinsic and extrinsic properties on WVP. In addition to these, this work combine several extrinsic properties which are presented separately during other studies. The first time, in this study the influence of the air velocity on WVP was investigated. Results on both hydrophilic and hydrophobic fabrics showed a great variation in the results when varying the location of the cups inside the climatic chamber. This is the reason why future studies look at studying more deeply the effect of air velocity on the WVP properties on different types of fabrics by connecting WVP values with air velocity values. It is also planned to make tests with the rotation device and by fixing the value of the temperature and RH. The objective will be to obtain reliable values that do not take into account the effect of air velocity.

Reports on an automated apparatus and test procedure to determine the convective and diffusive gas and vapor transport properties of small pieces of woven and nonwoven fabrics, membranes, and foams. The apparatus allows measurement of these properties in the very small quantities typical of material development programs, where the largest sample available may only be 1‐10cm² in area. The convection/diffusion test method is useful for determining the gas flow resistance property and water vapor diffusion properties from a single experimental run. This eliminates the need for two separate tests, which is the usual procedure. The apparatus may also be used to perform separate tests for the diffusion property or the air permeability property, which may have some advantages when materials exhibit strongly concentration‐dependent transport properties. The convection/diffusion test method is well‐suited for rapid screening and comparison of the properties of a large number of materials with widely‐varying transport properties.

The liquid water and water vapour transfer properties of fabrics play an important and decisive role in determining thermal comfort properties of clothing systems. The purpose of this paper is to analyse the effects of fabric composition (98 percent cotton–2 percent elastane and 100 percent cotton) and finishing treatments (rigid, resin, bleaching and softening) on the wicking, drying and water vapour permeability (WVP) properties of denim fabrics.

The research design for this study consists of experimental study. Two fabric compositions (98 percent cotton–2 percent elastane and 100 percent cotton) and four finishing treatments (rigid, resin, bleaching and softening) were evaluated to see the effects of elastane and finishing treatments on wicking, drying and WVP properties of woven denim fabrics. Results were analysed statistically.

Experimental results showed that the transfer wicking, drying and WVP values of denim fabrics were significantly influenced by fabric weight, fibre composition and finishing treatments.

The wicking ability of sweat from the skin to the outer environment of a skin contact fabric layer is the primary requirement.

As a result of the literature review, it was seen that there are some studies in the literature about comfort properties of denim fabrics, but there is no study concerning the water vapour transmission, wicking and drying properties of denim fabrics.

This paper aims to provide a critical review of water generation from atmospheric air by using desiccant materials. Over the past few years, there has been very high stress on water scarcity, especially in Asian and African countries. Because of this insecurity, many countries are focusing on their research in the field of water technologies. Water generation from atmospheric air by using desiccant materials is one of the techniques among the air-to-water generators (AWGs).

A structured and systematic literature review has been presented to observe and understand the past trend/patterns in the field of water generation from atmospheric air by using desiccant materials. To understand the water generation technologies based on desiccant materials, the research papers from the years 1987 to 2022 have been studied and included.

The properties of the different and most probable desiccant materials in the field of AWGs have been discussed. A detailed review of testing reports of collected water samples has also been presented in tabular form. Finally, the economic analysis has been done and future prospects have been discussed. It is also found that the capacity of solid desiccant materials to adsorb the water is less as compared to liquid desiccant materials. But, the adsorption capacity can be improved by using composite desiccant materials.

The uniqueness of this manuscript lies in the compiling and examination of the existed published research papers, including variables such as author, year and geographical location, experimental/simulative, types of desiccant material, type of setup, desiccant material type and quantity and type of concentrator. This manuscript provides critique to the empirical and conceptual research in AWG technologies and also stimulates researchers to explore the topic very carefully.

High levels of interior water vapour lead to condensation and black mould that in turn represent significant risks to residential properties and their occupants. Beliefs about window opening are good predictors of the degree to which householders will actually open windows to purge their homes of water vapour, including water vapour that they themselves generate. The present study tested if a short information-giving intervention could enhance householders’ beliefs that foster window opening as purge ventilation and, in turn, lead to greater window opening.

Data were collected from 242 UK householders with robust psychometrically sound measures embedded in an online self-report survey that also presented the intervention information.

The intervention led participants, and males in particular, to have significantly greater concerns about condensation and mould and significantly less concerns about heat loss costs arising from opening windows, and these altered beliefs in turn predicted a greater intention to open windows in the future.

By sharing simple information, surveyors and other building professionals can help householders take the simple step of opening their windows and so reduce the threats that condensation and mould present to themselves and their homes.

This is the first study to test (1) a time-based model that predicted the intervention would have a positive effect on specific window opening attitudes and that those new attitudes would in turn affect window opening intentions, and (2) if the intervention had different effects on men and women.

Sleep is a vital and a basic activity of human life and it is a physiological need for human body. Sleep quality is directly influenced by the comfort conditions of sleep environment. The purpose of this paper is to define the role of textile materials utilized as bed fabrics on air and mass transfer from the human body.

Thermal conductivity, thermal resistance, thickness, water vapour permeability and air permeability properties of fabrics were analyzed and statistically evaluated. Thermal conductivity and resistance measurements were performed in Alambeta test instrument. Water vapour permeability tests were done according to the Rotating Platform method, and air permeability was measured in FX 3300 Textest air permeability tester. Relationships between comfort parameters were statistically evaluated with correlation analysis.

Comfort is a major concept in the determination of overall life quality as well as sleep quality of a resting person. Therefore academic studies about thermal comfort prediction of sleep environment and bed surface fabrics are of great importance. This study investigates conventional mattress ticking fabrics in terms of comfort parameters and defines the important fabric properties on comfort parameters.

Sleep comfort is a promising area in textile comfort studies with its dynamics different from body thermal comfort during daily life. However, in general comfort studies are about garment materials which are in direct contact with the skin. This study tries to define the comfort status of textile materials which have indirect contact with the human body surface during sleep duration.