The output signals from transducers and are used by {HEAD ~ data processing unit} to compute {TAIL ~ the total concentration} of hydrocarbon gases and vapors and the concentration of methane gas within cells and  
to compute
The output signals from transducers and are used by { HEAD ~ data processing unit } to compute { TAIL ~ the total concentration } of hydrocarbon gases and vapors and the concentration of methane gas within cells and
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH