An increase in {TAIL ~ zinc} from {HEAD ~ about 23%} to about 28 30% results in markedly higher electrical conductivity 
An increase in { TAIL ~ zinc } from { HEAD ~ about 23 % } to about 28 30 % results in markedly higher electrical conductivity
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH