means for generating {HEAD ~ an electrical signal} correlated to {TAIL ~ the duration} of time that said temperature is within a first temperature range wherein particulates accumulate on said lining; and 
correlated to
means for generating { HEAD ~ an electrical signal } correlated to { TAIL ~ the duration } of time that said temperature is within a first temperature range wherein particulates accumulate on said lining ; and
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL 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