Table 2. ANOVA results of significant factors in quadratic model.

Source	Df	Adj SS	Adj MS	F-value	p-value
Model	7	328.000	46.857	18.07	0.0001
Linear	4	218.185	54.546	21.04	<0.0001
Temperature/°C (X1)	1	11.740	11.740	4.53	0.047
t/min* (X2)	1	1.631	1.631	0.63	0.437
φ(water)/% (X3)	1	53.616	53.616	20.68	<0.0001
(V/m)/(mL/g) (X4)	1	145.078	145.078	55.96	<0.0001
Quadratic	2	86.503	43.251	16.68	<0.0001
X12	1	27.051	27.051	10.43	0.004
X42	1	48.513	48.513	18.71	<0.0001
Two-way interaction	1	20.278	20.278	7.82	0.012
X1·X2	1	20.278	20.278	7.82	0.012
Error	19	49.256	2.592
Lack-of-fit	14	43.460	3.104	2.68	0.141
Pure error	5	5.796	1.159
Total	26	377.255

R²=86.94%, R²(adj)=82.13%, R²(pred)=69.34%; *In the final model, while time as a single factor is not significant (p>0.05), it is significant in the 2-way interaction and is therefore included