Alternatively, {HEAD ~ the shuttle element} may simply be a separating element that does not form a tight seal in the paint line, but only forms {TAIL ~ an unsealed boundary} between the paint and the auxiliary medium 
Alternatively , { HEAD ~ the shuttle element } may simply be a separating element that does not form a tight seal in the paint line , but only forms { TAIL ~ an unsealed boundary } between the paint and the auxiliary medium
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH