This involves flowing a fluid over {TAIL ~ the surface} wherein the fluid contains positively charged ions and {HEAD ~ electrons} 
This involves flowing a fluid over { TAIL ~ the surface } wherein the fluid contains positively charged ions and { HEAD ~ electrons }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD