Jiang Wen is a Chinese actor.
Rack Phase Difference -LRB- RPD -RRB- is a difference in the elevation between rack teeth of the chords of any single leg of a jackup rig .. rack teeth. Rack and pinion. jackup rig. jackup rig. This relative displacement creates an additional load on the leg members , which may results in failure of structure members in case RPD reaches more than the allowable value .