Mathematical models for water vapour resistance prediction of printed garments

2017 ◽  
Vol 134 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Mladen Stančić ◽  
Nemanja Kašiković ◽  
Dragana Grujić ◽  
Dragoljub Novaković ◽  
Rastko Milošević ◽  
...  
Keyword(s):  
Mathematical Models ◽  
Water Vapour ◽  
Resistance Prediction ◽  
Water Vapour Resistance

scholarly journals Combined bound water and water vapour diffusion of Norway spruce and European beech in and between the principal anatomical directions

Holzforschung ◽  
2011 ◽  
Vol 65 (6) ◽  
pp. 819-828 ◽  
Author(s):  
Walter Sonderegger ◽  
Manuele Vecellio ◽  
Pascal Zwicker ◽  
Peter Niemz
Keyword(s):  
Diffusion Coefficient ◽  
Steady State ◽  
Water Vapour ◽  
Diffusion Coefficients ◽  
Bound Water ◽  
European Beech ◽  
Unsteady State ◽  
Water Vapour Diffusion ◽  
Vapour Diffusion ◽  
Water Vapour Resistance

Abstract The combined bound water and water vapour diffusion of wood is of great interest in the field of building physics. Due to swelling stresses, the steady-state-determined diffusion coefficient clearly differs from the unsteady-state-determined diffusion coefficient. In this study, both diffusion coefficients and the water vapour resistance factor of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.) were investigated for the principal anatomical directions (radial, tangential and longitudinal) and in 15° steps between these directions. The values were determined with the cup method as the basic principle. The unsteady-state-determined diffusion coefficient is, independent of the direction, about half that of the steady-state-determined diffusion coefficient. Both diffusion coefficients are about two to three times higher for spruce than for beech. They are up to 12 times higher in the longitudinal direction than perpendicular to the grain for spruce, and up to 15 times higher for beech. With increasing moisture content, the diffusion coefficients exponentially increase. The water vapour resistance factor shows converse values to the diffusion coefficients.

Some experiments on cavities behind disks

1965 ◽  
Vol 23 (4) ◽  
pp. 645-656 ◽  
Author(s):  
G. E. Gadd ◽  
S. Grant
Keyword(s):  
Mathematical Models ◽  
Water Vapour ◽  
Vapour Pressure ◽  
Atmospheric Pressure ◽  
Water Vapour Pressure ◽  
Water Tunnel ◽  
Cavity Pressure ◽  
Qualitative Discussion

Measurements of cavities behind disks in a water tunnel show that at high enough speeds the cavity pressure is not more than 30–40% higher than water-vapour pressure, even when at atmospheric pressure the tunnel water is nearly saturated with air. No other hard conclusions can be drawn from the investigations, which showed many puzzling features, discussed below. It is hoped, however, that the qualitative discussion may prove useful to theoreticians who may seek to improve existing mathematical models of cavitation by taking a more realistic account of the physics of the flow.

scholarly journals The change of water vapour resistance of materials used for the clothing production during exploitation

2016 ◽  
Vol 5 (2) ◽  
pp. 73-78 ◽  
Author(s):  
Mirjana Reljic ◽  
Jovan Stepanovic ◽  
Branislava Lazic ◽  
Nenad Cirkovic ◽  
Dragana Cerovic
Keyword(s):  
Water Vapour ◽  
Water Vapour Resistance ◽  
Materials Used

scholarly journals Correlation of Air Permeability to Other Breathability Parameters of Textiles

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 140
Author(s):  
Karel Adámek ◽  
Antonin Havelka ◽  
Zdenek Kůs ◽  
Adnan Mazari
Keyword(s):  
Water Vapour ◽  
Air Permeability ◽  
Water Vapour Permeability ◽  
Textile Material ◽  
Permeability Measurement ◽  
Smart Textiles ◽  
Vapour Permeability ◽  
Clothing Comfort ◽  
Strong Relation ◽  
Water Vapour Resistance

In the field of textile comfort of smart textiles, the breathability of the material is very important. That includes the flow of air, water and water vapours through the textile material. All these experiments are time consuming and costly; only air permeability is much faster and economical. The research is performed to find correlation between these phenomena of breathability and to predict the permeability based on only the air permeability measurement. Furthermore, it introduces a new way of expressing the Ret (water vapour resistance) unit according to SI standards as it is connected with the air permeability of garments. The need to find a correlation between air permeability and water vapour permeability is emphasised in order to facilitate the assessment of clothing comfort. The results show that there is a strong relation between air permeability and water vapour permeability for most of the textile material.

PACKAGING: VI. THE RELATIVE MERITS OF VARIOUS TYPES OF BAG CONSTRUCTION IN PRODUCING WATER-VAPOUR RESISTANT PACKAGES

1947 ◽  
Vol 25f (1) ◽  
pp. 8-12
Author(s):  
C. G. Lavers
Keyword(s):  
Water Vapour ◽  
Heat Sealing ◽  
Heat Seal ◽  
Water Vapour Resistance

Water-vapour penetration was measured on pouch, flat, wedge, and square liner bags fabricated from Reynold's Metal A-51, 300 M.S.A.T. "Cellophane" coated 40 lb. per ream with a flexible wax composition, 55 lb. laminated bleached glassine, and 300 M.S.A.T. Cellophane. The bags were closed, where the material permitted, by heat-, glue-, and pressure-sealing, and by folding with or without tin-tie closures.When Reynold's Metal A-51 or waxed Cellophane was used, excellent water-vapour resistance could be achieved with any of the bag types investigated, and a folded closure was as efficient as a heat-seal. With all materials except 300 M.S.A.T. Cellophane, bags made with glue were almost as good as those with heat-sealed construction. Unwaxed Cellophane or glassine provided more protection when the simpler forms of bags (pouch) were used. With unwaxed Cellophane, heat-sealing appeared to make a better liner than the use of glue, and a heat- or glue-sealed closure was superior to a double fold.

scholarly journals Treatment of condensation in sandwich panels without known vapour resistance of sealant

2020 ◽  
Vol 172 ◽  
pp. 07007
Author(s):  
Gregor Vidmar
Keyword(s):  
Water Vapour ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Building Envelope ◽  
Climatic Data ◽  
Material Parameters ◽  
Steel Sheets ◽  
Equivalent Systems ◽  
Water Vapour Resistance

In order to calculate amount of interstitial condensation in a building envelope, water vapour resistance of each layer is of importance. Once having it, 1D calculation according to ISO 13788 with monthly average vapour pressures can be applied. In EN 14509 sandwich panels are considered to be impermeable for water vapour, thus (according to the standard) water vapour cannot enter from outside and condensate in the panels. But it is not always true for real sandwich panels, because joints between neighbouring panels can cause non-neglecting water vapour bridges. Although in measurements of linear water vapour transmittance of the joints (Ψv) stationary boundary vapour pressures can be applied, the measurements can be long lasting. We shortened time needed to get Ψv performing simulations in Delphin 6.0. We simulated panels and steel sheets with joints using constant boundary vapour pressures and compared the results with the results of measurements on the equivalent systems. In systems under consideration a sealant in built-in-state, located at a joint of a sandwich panel, is a compressed EPDM tube. It is impossible to directly measure its effective μ according to ISO 12572. In the paper we study to which precision it is possible to determine it using measurements and simulations. Once having effective μ of the sealant (if all other necessary material parameters available) one can simulate condensation in envelopes including sandwich panels in 2D according to EN 15026 using hourly climatic data. Another goal of the study was determination of differences in resulting Ψv values when varying narrowest part of the gap dGAP at the joint in the panels without any sealant. Results confirm significant sensibility of Ψv to variations of dGAP.

Sign in / Sign up

Export Citation Format

Share Document