After a predetermined time {HEAD ~ the valve} in {TAIL ~ the closed system} is opened allowing the fluids therein to flow freely 
in
After a predetermined time { HEAD ~ the valve } in { TAIL ~ the closed system } is opened allowing the fluids therein to flow freely
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH