Abstract: A laminar flow control system for incorporation in, for example, an aircraft flying surface includes a suction panel comprising a perforated skin (20, 40) mounted on a base member (60), a plenum chamber (30) being in communication with a plurality of micro channels (90) formed in the top surface of the base member (60), the micro channels (90) being in communication with the holes (40) in the skin (20).

Abstract: A laser markable white pigment composition includes a first pigment which is markable by ultraviolet laser, a second pigment, which is nonabsorbing in the ultraviolet region of the optical spectrum and which has a white appearance in the visible region of the optical spectrum, with the ratio of the amount of first pigment to amount of second pigment being in the range of from 4:1 to 1:10, so that the second pigment is present in an amount sufficient to increase the optical density, that is the whitening effect, of the composition, without adversely affecting the laser markability of the composition, and a carrier which is at least one fluoropolymer transparent in the ultraviolet region of the optical spectrum.