A pair of blowers 83, 83, blow {HEAD ~ cooling air} over {TAIL ~ heat sinks} 82, 82 
over
A pair of blowers 83 , 83 , blow { HEAD ~ cooling air } over { TAIL ~ heat sinks } 82 , 82
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH