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