an arrangement for determining the combustion duration from {HEAD ~ an energy conversion} which is calculated using {TAIL ~ a polytropic equation} of state 
is calculated using
an arrangement for determining the combustion duration from { HEAD ~ an energy conversion } which is calculated using { TAIL ~ a polytropic equation } of state
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH