{HEAD ~ This source} may include {TAIL ~ an airstream} entrained with particles which is discharged into the space through an orifice; the airstream diverging as it enters the space 
{ HEAD ~ This source } may include { TAIL ~ an airstream } entrained with particles which is discharged into the space through an orifice ; the airstream diverging as it enters the space
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH