The test machine is based on a machine manufactured by the Timken Company from 1935 to 1972, It is now an industry recognized standard test to compare extreme pressure resistance of greases and oils in a reproducible way.
12.
As a special form of the axial expansion joint, the universal expansion joint has only a limited pressure resistance for stability reasons and, moreover, loads the adjacent pipe supports with the axial compressive force resulting from the internal pressure.
13.
By lowering the cabin pressure at altitude, manufacturers don't have to build as much pressure resistance into their aircraft, which allows them to be cheaper and lighter, and hence more economical . talk ) 16 : 55, 24 January 2012 ( UTC)
