The panel of {HEAD ~ substrate material} 18 has {TAIL ~ a surface} 19 and a thickness t 
The panel of { HEAD ~ substrate material } 18 has { TAIL ~ a surface } 19 and a thickness t
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH