Experimental Study for Influence of Surfactants Chemical Microstructures on Wetting Effect about Coal Dust in Tongchuan Mining Area

Table 11

Assignment of variables in the model of evaluating the wettability of surfactants to bituminous coal dust.

Hydroxyl	Aromatic ring carbon	Unprotonated carbon	Bridged aromatic carbon	Ether group	Aliphatic methyl/arylmethyl	Protonated carbon	Contact angle
x1	x2	x3	x4	y1	y2	y3	Z