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The R-value (in K ⋅ m 2/ W) is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive [2] flow of heat, in the context of construction. [3]. R-value is the temperature difference per unit of heat flux needed to sustain one unit of heat flux between the ...
Thermal insulance (R-value) is a measure of a material's resistance to the heat current. It quantifies how effectively a material can resist the transfer of heat through conduction, convection, and radiation.
In crystallography, the R-factor (sometimes called residual factor or reliability factor or the R-value or R Work) is a measure of the agreement between the crystallographic model and the experimental X-ray diffraction data. In other words, it is a measure of how well the refined structure predicts the observed data. [1]
An R 2 of 1 indicates that the regression predictions perfectly fit the data. Values of R 2 outside the range 0 to 1 occur when the model fits the data worse than the worst possible least-squares predictor (equivalent to a horizontal hyperplane at a height equal to the mean of the observed data). This occurs when a wrong model was chosen, or ...
Thermal conductivity and resistivity. The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by , , or and is measured in W·m −1 ·K −1. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal conductivity.
The gas constant is the constant of proportionality that relates the energy scale in physics to the temperature scale and the scale used for amount of substance. Thus, the value of the gas constant ultimately derives from historical decisions and accidents in the setting of units of energy, temperature and amount of substance.
R-factor (crystallography), a measure of the agreement between the crystallographic model and the diffraction data. R0 or R number, the basic reproduction number in epidemiology. In computer science, a pure value which cannot be assigned to. In statistics, the Pearson product-moment correlation coefficient, or simply correlation coefficient.
Thinsulate is a brand of synthetic fiber thermal insulation used in clothing. The word is a portmanteau of the words thin and insulate, trademarked by 3M. [1] The material is made by the 3M Corporation and was first sold in 1979. [2] It was originally marketed as an inexpensive alternative to down; at the time, 3M claimed it was twice as warm ...