Thermal conductivity the list of thermal conductivities. These should be considered approximate due to the uncertainties related to material definitions. High energy generation rates within electronics or turbines require the use of materials with high thermal conductivity such as copper "(see: Copper in heat exchangers)", aluminium, and silver. On the other hand, materials with low thermal conductance, such as polystyrene foam and fire brick, are used in building construction or in furnaces in an effort to slow the flow of heat, i.e. for insulation purposes. The reciprocal of thermal conductivity is "thermal resistivity", usually expressed in kelvin-meters per watt (K⋅m⋅W). For a
Composite reflectivity Composite reflectivity The composite reflectivity is the maximum dBZ reflectivity from any of the reflectivity angles of the NEXRAD weather radar. The reflectivity on individual PPI angles show the precipitation intensity at that specific angle above the horizon. Some of these angles are .5, 1.45, 2.4, and 3.35 degrees with the Doppler radar having up to 14 angles when it's in Severe Mode. In the Composite, the highest intensities amongst those available in the different angles above each point of the image will be displayed. In the Canadian weather radar network, this is called MAXR, for "Maximum reflectivity" in the