. . . . "Heat Flow Rate per Unit Area"@en . . . . . "http://en.wikipedia.org/wiki/Heat_flux"^^ . . . . "http://www.iso.org/iso/catalogue_detail?csnumber=31890"^^ . . "\\(\\textit{Heat Flux}\\) is the heat rate per unit area. In SI units, heat flux is measured in \\(W/m^2\\). Heat rate is a scalar quantity, while heat flux is a vectorial quantity. To define the heat flux at a certain point in space, one takes the limiting case where the size of the surface becomes infinitesimally small."^^ . . . . . . . .