An electrical bias is applied across {TAIL ~ the gap} between {HEAD ~ the belt} and the overcoated ohmic layer 
An electrical bias is applied across { TAIL ~ the gap } between { HEAD ~ the belt } and the overcoated ohmic layer
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH