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