{HEAD ~ The fuel} is passed over the cores and {TAIL ~ metal particles} in passing between the inlet and outlet 
{ HEAD ~ The fuel } is passed over the cores and { TAIL ~ metal particles } in passing between the inlet and outlet
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH