an end cap coupled to the stack for defining {HEAD ~ an anode air stream plenum} in {TAIL ~ fluid communication} with the anodes 
an end cap coupled to the stack for defining { HEAD ~ an anode air stream plenum } in { TAIL ~ fluid communication } with the anodes
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH