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