{HEAD ~ An average residence time} of {TAIL ~ between 5 and 500 milliseconds} of the hydrocarbons during thermal cracking has proven to be effective 
of
{ HEAD ~ An average residence time } of { TAIL ~ between 5 and 500 milliseconds } of the hydrocarbons during thermal cracking has proven to be effective
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH