wherein {HEAD ~ positioning} of the plunger within the chamber is artificially controlled by {TAIL ~ the positioning device} to allow the volume of the enclosure to be pre determinable 
is artificially controlled by
wherein { HEAD ~ positioning } of the plunger within the chamber is artificially controlled by { TAIL ~ the positioning device } to allow the volume of the enclosure to be pre determinable
OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH