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