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The most common international unit for the MVTR is g/m 2 /day, or "metric perm". In the USA, g/100in 2 /day is also in use, which is 0.064516 (approximately 1/15) of the value of g/m 2 /day units. Typical rates in aluminium foil laminates may be as low as 0.001 g/m 2 /day, whereas the rate in fabrics can measure up to several thousand g/m 2 /day.
A variant of the metric perm is used in DIN Standard 53122, where permeance is also expressed in grams per square meter per day, but at a fixed, "standard" vapor-pressure difference of 17.918 mmHg. This unit is thus 17.918 times smaller than a metric perm, corresponding to about 0.084683 of a U.S. perm.
To take the effects of workmanship-related factors fully into account it is necessary to carry out a thermal transmittance measurement. [4] Example of measurement system for thermal transmittance according to ISO 9869 and ASTM C1155, model TRSYS. ISO 9869 describes how to measure the thermal transmittance of a roof or a wall by using heat flux ...
Its escape into the environment is a concern. Other ingredients in vinyl flooring vary widely, and some are harmful. The thickness of the sheet and the wear layer determines the durability of the floor; unlike linoleum, vinyl flooring is usually not homogeneous, and once it wears through the print layer, it will be obviously damaged.
The transient hot wire method (THW) is a very popular, accurate and precise technique to measure the thermal conductivity of gases, liquids, [3] solids, [4] nanofluids [5] and refrigerants [6] in a wide temperature and pressure range. The technique is based on recording the transient temperature rise of a thin vertical metal wire with infinite ...
A relatively new method [7] [8] for describing the thickness and shape of the thermal boundary layer utilizes the moment method commonly used to describe a random variable's probability distribution. The moment method was developed from the observation that the plot of the second derivative of the thermal profile for laminar flow over a plate ...
Most experimentally determined values of the thermal contact resistance fall between 0.000005 and 0.0005 m 2 K/W (the corresponding range of thermal contact conductance is 200,000 to 2000 W/m 2 K). To know whether the thermal contact resistance is significant or not, magnitudes of the thermal resistances of the layers are compared with typical ...
Polymers represent another large area in which thermal analysis finds strong applications. Thermoplastic polymers are commonly found in everyday packaging and household items, but for the analysis of the raw materials, effects of the many additive used (including stabilisers and colours) and fine-tuning of the moulding or extrusion processing used can be achieved by using differential scanning ...