Table 2.

Experimental factors and their levels

Process parameters	Symbol	Levels of experimentc
		−1.682	−1	0	1	1.682
Input power (Kw)	P	28	30	33	35	37
Spraying distance (mm)	S	58	75	100	125	142
Primary gas flow rate (L/min)	A	32	36	42	48	52