Substrate means the surface onto which a coating is applied or into which a coating is impregnated.
Diameter means the diameter of the stem of a tree measured outside the bark at a specified point of measurement.
Density means the permitted number of dwelling units per
Fluoroscopic imaging assembly means a subsystem in which X-ray photons produce a visual image. It includes the image receptor(s) such as the image intensifier and spot-film device, electrical interlocks, if any, and structural material providing linkage between the image receptor and diagnostic source assembly.
Sensor means any measurement device that is not part of the vehicle itself but installed to determine parameters other than the concentration of gaseous and particle pollutants and the exhaust mass flow.