Relationship between accumulated temperature and quality of paddy

Figures & data

Figure 1. Structure diagram of the grain thin-layer drying test device with multi-parameter regulating function: 1. wind shunt; 2. axial flow fan; 3. material bin door; 4. material tray; 5. sensor bin; 6. electric sealing valve; 7. heating pipe; 8. inner tank; 9. wet exhaust fan; 10. test-bed shell; 11. sensor group; and 12. humidifier

Figure 2. The grain thin-layer drying test device picture

Table 1. Orthogonal test table of four factors and five levels

Factor	Level
	−2	−1	0	1	2
Drying medium temperature x1/°C	43	39	35	31	27
Drying medium relative humidity x2/%	65	60	55	50	45
Initial moisture content x3/%	25	23	21	19	17
Drying medium flow velocity x4/m/s	0.8	0.7	0.6	0.5	0.4

Table 2. Experimental statistical results

Groups	X1	X2	X3	X4	The crack additional percentage (%)	Accumulated temperature (ºC·h)
1	−1	−1	−1	−1	1.57	208.0675
2	1	−1	−1	−1	4.29	118.7267
3	−1	1	−1	−1	0.54	250.4419
4	1	1	−1	−1	3.22	166.5126
5	−1	−1	1	−1	1.58	257.6739
6	1	−1	1	−1	4.25	174.5308
7	−1	1	1	−1	1.60	296.9774
8	1	1	1	−1	4.26	228.4642
9	−1	−1	−1	1	2.12	225.1254
10	1	−1	−1	1	4.74	145.5214
11	−1	1	−1	1	1.05	228.9124
12	1	1	−1	1	3.56	151.2837
13	−1	−1	1	1	2.23	261.1578
14	1	−1	1	1	4.71	185.1898
15	−1	1	1	1	2.04	282.2168
16	1	1	1	1	4.69	213.4228
17	−2	0	0	0	1.25	288.4268
18	2	0	0	0	6.54	163.4015
19	0	−2	0	0	2.75	175.4927
20	0	2	0	0	1.72	253.9445
21	0	0	−2	0	2.27	123.2575
22	0	0	2	0	3.31	238.9905
23	0	0	0	−2	1.75	218.2773
24	0	0	0	2	2.74	215.1145
25	0	0	0	0	2.33	215.8807
26	0	0	0	0	2.25	221.4948
27	0	0	0	0	2.34	212.5347
28	0	0	0	0	2.48	210.0785
29	0	0	0	0	2.12	227.5961
30	0	0	0	0	2.48	203.4232
31	0	0	0	0	2.22	206.7365
32	0	0	0	0	2.25	186.1927
33	0	0	0	0	2.43	215.2349
34	0	0	0	0	2.34	215.7749
35	0	0	0	0	2.15	229.6871
36	0	0	0	0	2.35	197.8779

Table 3. Influence of various factors on the crack additional percentage of paddy

Source of variance		Degree of freedom	Sum of squares	Mean square	F value	P value	Significance
Regression	Model	14	53.65	3.83	336.53	<0.0001	Yes
	X1	1	41.54	41.54	3648.52	<0.0001	Yes
	X2	1	1.8	1.8	158.47	<0.0001	Yes
	X3	1	1.67	1.67	146.77	<0.0001	Yes
	X4	1	1.41	1.41	123.59	<0.0001	Yes
	X1X2	1	8.32E-06	8.32E-06	7.31E-04	0.9787	No
	X1X3	1	1.97E-04	1.97E-04	0.017	0.8966	No
	X1X4	1	0.015	0.015	1.29	0.2697	No
	X2X3	1	1.08	1.08	95.1	<0.0001	Yes
	X2X4	1	9.28E-03	9.28E-03	0.82	0.3768	No
	X3X4	1	1.03E-03	1.03E-03	0.091	0.7664	No
	X1^2	1	5.5	5.5	482.83	<0.0001	Yes
	X2^2	1	3.42E-05	3.42E-05	3.00E-03	0.9568	No
	X3^2	1	0.61	0.61	53.93	<0.0001	Yes
	X4^2	1	1.40E-04	1.40E-04	0.012	0.9128	No
Residual Error	Lack of Fit	10	0.086	8.59E-03	0.62	0.7723	No
	Pure Error	11	0.15	0.014
	Total Error	21	0.24	0.011
Total		35	53.89

Figure 3. Response surface diagram of the influence of each control factor on the crack additional percentage. (a) Response surface diagram of the influence of X₁ and X₂ on the crack additional percentage. (b) Response surface diagram of the influence of X₁ and X₃ on the crack additional percentage. (c) Response surface diagram of the influence of X₁ and X₄ on the crack additional percentage. (d) Response surface diagram of the influence of X₂ and X₃ on the crack additional percentage. (e) Response surface diagram of the influence of X₂ and X₄ on the crack additional percentage. Response surface diagram of the influence of X₃ and X₄ on the crack additional percentage

Table 4. Relative error table of the regression equation of the crack additional percentage of paddy

Factor				The crack percentage of raw grain	The crack percentage after drying	The crack additional percentage (Experimental value)	Analog value	Relative error
X1	X2	X3	X4
29	48	22	0.6	6.33	20.00	2.1596	2.2392	3.69%
33	52	20	0.5	6.67	20.67	2.0990	2.2607	7.71%
40	62	24	0.7	6.00	42.67	6.1117	6.3159	3.34%

Table 5. Influence of various factors on the accumulated temperature of paddy

Source of variance		Degree of freedom	Sum of squares	Mean square	F value	P value	Significance
Regression	Model	14	59158.41	4225.6	38.36	<0.0001	Yes
	X1	1	32044.97	32044.97	290.92	<0.0001	Yes
	X2	1	6638.1	6638.1	60.26	<0.0001	Yes
	X3	1	16880.94	16880.94	153.25	<0.0001	Yes
	X4	1	9.24	9.24	0.084	0.775	No
	X1X2	1	53.26	53.26	0.48	0.4945	No
	X1X3	1	72.61	72.61	0.66	0.426	No
	X1X4	1	32.87	32.87	0.3	0.5907	No
	X2X3	1	114.59	114.59	1.04	0.3194	No
	X2X4	1	969.64	969.64	8.8	0.0074	Yes
	X3X4	1	32.36	32.36	0.29	0.5935	No
	X1^2	1	494.37	494.37	4.49	0.0462	Yes
	X2^2	1	40.98	40.98	0.37	0.5484	No
	X3^2	1	1689.9	1689.9	15.34	0.0008	Yes
	X4^2	1	84.6	84.6	0.77	0.3907	No
Residual Error	Lack of Fit	10	656.64	65.66	0.44	0.899	No
	Pure Error	11	1656.5	150.59
	Total Error	21	2313.14	110.15
Total		35	61471.56

Figure 4. Response surface diagram of the influence of each control factor on the accumulated temperature. (a) Response surface diagram of the influence of X₁ and X₂ on the accumulated temperature. (b) Response surface diagram of the influence of X₁ and X₃ on the accumulated temperature. (c) Response surface diagram of the influence of X₁ and X₄ on the accumulated temperature. (d) Response surface diagram of the influence of X₂ and X₃ on the accumulated temperature. (e) Response surface diagram of the influence of X₂ and X₄ on the accumulated temperature. (f) Response surface diagram of the influence of X₃ and X₄ on the accumulated temperature

Table 6. Relative error of the regression equation of the accumulated temperature of paddy

Factor				Drying time	Drying temperature	Accumulated temperature (Experimental value)	Analog value	Relative error
X1	X2	X3	X4
29	48	22	0.6	9.50	29	275.5	265.5331	3.62%
33	52	20	0.5	6.18	33	203.94	208.9425	2.45%
40	62	24	0.7	5.48	40	219.2	219.6760	0.22%

Figure 5. Contour map of the accumulated temperature and the drying quality