{HEAD ~ The combustion heat} generated during incineration of the waste gas mixed with the air establishes strong buoyancy and produces {TAIL ~ a swirling air stream} 
produces
{ HEAD ~ The combustion heat } generated during incineration of the waste gas mixed with the air establishes strong buoyancy and produces { TAIL ~ a swirling air stream }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL