Coefficient of Friction of Pulse Grains on Various Surfaces at Different Moisture Content

Figures & data

Table 1 Static and kinetic coefficient of friction of pulses on various surfaces at different moisture content levels

Coefficient of friction
Static coefficient of friction				Kinetic coefficient of friction
Pulse	Moisture content (% (wb))	Smooth concrete	Galvanized Iron sheet	Ply wood	Glass sheet	Smooth concrete	Galvanized Iron sheet	Ply wood	Glass sheet
Chickpea	9.25	0.51	0.42	0.42	0.39	0.49	0.41	0.40	0.38
14.29	0.53	0.44	0.43	0.41	0.50	0.42	0.41	0.40
17.21	0.54	0.45	0.44	0.41	0.52	0.43	0.42	0.41
21.25	0.55	0.46	0.45	0.43	0.53	0.44	0.43	0.42
Mean	0.53 (0.02)	0.44 (0.01)	0.44 (0.01)	0.41(0.01)	0.51 (0.01)	0.42 (0.01)	0.42 (0.01)	0.40 (0.01)
Khesari	10.28	0.51	0.42	0.41	0.39	0.49	0.40	0.40	0.38
14.16	0.52	0.43	0.42	0.40	0.50	0.41	0.41	0.39
18.87	0.53	0.44	0.44	0.41	0.51	0.42	0.42	0.40
22.28	0.54	0.45	0.45	0.42	0.53	0.44	0.43	0.41
Mean	0.52 (0.01)	0.44 (0.01)	0.43 (0.01)	0.41 (0.01)	0.51 (0.02)	0.42 (0.01)	0.41(0.01)	0.39 (0.01)
Blackgram	10.38	0.50	0.42	0.41	0.39	0.48	0.40	0.39	0.38
13.24	0.51	0.42	0.42	0.40	0.49	0.41	0.40	0.38
17.51	0.52	0.44	0.43	0.40	0.51	0.42	0.41	0.39
22.38	0.54	0.45	0.45	0.42	0.52	0.43	0.43	0.41
Mean	0.52 (0.01)	0.43 (0.01)	0.43 (0.01)	0.40 (0.01)	0.50 (0.01)	0.41 (0.01)	0.41 (0.01)	0.39 (0.01)
Cowpea	8.76	0.46	0.41	0.40	0.38	0.45	0.37	0.37	0.37
11.89	0.47	0.42	0.41	0.39	0.46	0.38	0.38	0.37
14.30	0.48	0.43	0.42	0.40	0.47	0.40	0.39	0.38
20.76	0.49	0.44	0.44	0.41	0.49	0.41	0.40	0.40
Mean	0.48 (0.01)	0.42 (0.01)	0.42 (0.01)	0.39 (0.01)	0.47 (0.01)	0.39 (0.01)	0.39 (0.01)	0.38 (0.01)
Field pea	10.2	0.47	0.41	0.40	0.38	0.46	0.38	0.37	0.37
14.17	0.48	0.43	0.41	0.39	0.47	0.39	0.38	0.38
17.18	0.49	0.44	0.42	0.40	0.48	0.40	0.40	0.39
22.21	0.50	0.44	0.44	0.41	0.49	0.41	0.40	0.40
Mean	0.48 (0.01)	0.43 (0.01)	0.42 (0.01)	0.40 (0.01)	0.47 (0.01)	0.39 (0.01)	0.39 (0.01)	0.38 (0.01)
Mungbean	9.14	0.46	0.40	0.39	0.37	0.43	0.37	0.37	0.36
13.19	0.47	0.42	0.40	0.38	0.45	0.38	0.37	0.37
18.19	0.48	0.43	0.41	0.39	0.46	0.39	0.39	0.38
21.14	0.50	0.44	0.42	0.40	0.42	0.41	0.40	0.39
Mean	0.48 (0.02)	0.42 (0.01)	0.40 (0.01)	0.39 (0.01)	0.45 (0.02)	0.39 (0.01)	0.38 (0.01)	0.37 (0.01)
Lentil	10.33	0.46	0.41	0.39	0.37	0.43	0.37	0.36	0.35
14.25	0.47	0.42	0.40	0.38	0.44	0.38	0.37	0.36
18.17	0.48	0.43	0.41	0.39	0.46	0.39	0.38	0.37
22.10	0.50	0.43	0.42	0.40	0.47	0.40	0.40	0.38
Mean	0.47 (0.01)	0.42 (0.01)	0.40 (0.01)	0.38 (0.01)	0.45 (0.02)	0.38 (0.01)	0.38 (0.01)	0.37 (0.01)

Note: Values in the parentheses are standard deviation.

Table 2 The regression equations and corresponding coefficient of determination (R ²) of static and kinetic coefficient of friction with moisture content of grains on various surfaces

Static coefficient of friction		Kinetic coefficient of friction
Grain type	Regression equation	R ^2	Regression equation	R ^2
Chickpea	μ c  = 0.0036ω + 0.48	0.998	μ c  = 0.0032ω + 0.46	0.978
μ gl = 0.0034ω + 0.39	0.996	μ gl = 0.0025ω + 0.38	0.957
μ p  = 0.0032ω + 0.39	0.995	μ p  = 0.0026ω + 0.38	0.992
μ g  = 0.0029ω + 0.36	0.998	μ g  = 0.0029ω + 0.36	0.997
Khesari	μ c  = 0.0024ω + 0.49	0.982	μ c  = 0.0033ω + 0.45	0.996
μ gl = 0.0024ω + 0.40	0.982	μ gl = 0.0026ω + 0.38	0.972
μ p  = 0.0029ω + 0.38	0.988	μ p  = 0.0026ω + 0.38	0.972
μ g  = 0.0026ω + 0.36	0.992	μ g  = 0.0025ω + 0.35	0.981
Blackgram	μ c  = 0.0028ω + 0.47	0.993	μ c  = 0.0032ω + 0.45	0.998
μ gl = 0.0029ω + 0.39	0.998	μ gl = 0.0028ω + 0.37	0.988
μ p  = 0.0030ω + 0.38	0.990	μ p  = 0.003ω + 0.36	0.995
μ g  = 0.0025ω + 0.36	0.981	μ g  = 0.0026ω + 0.35	0.998
Cowpea	μ c  = 0.0028ω + 0.44	0.976	μ c  = 0.0033ω + 0.42	0.979
μ gl = 0.0025ω + 0.39	0.998	μ gl = 0.0031ω + 0.34	0.953
μ p  = 0.0029ω + 0.38	0.986	μ p  = 0.0028ω + 0.35	0.929
μ g  = 0.0027ω + 0.35	0.934	μ g  = 0.0025ω + 0.34	0.996
Fieldpea	μ c  = 0.0027ω + 0.44	0.993	μ c  = 0.0028ω + 0.43	0.962
μ gl = 0.0027ω + 0.34	0.975	μ gl = 0.003ω + 0.34	0.987
μ p  = 0.0031ω + 0.37	0.994	μ p  = 0.0028ω + 0.34	0.940
μ g  = 0.0027ω + 0.35	0.986	μ g  = 0.0023ω + 0.35	0.982
Mungbean	μ c  = 0.0034ω + 0.42	0.993	μ c  = 0.0035ω + 0.40	0.976
μ gl = 0.0034ω + 0.39	0.996	μ gl = 0.0031ω + 0.34	0.982
μ p  = 0.0032ω + 0.39	0.995	μ p  = 0.0028ω + 0.34	0.983
μ g  = 0.0029ω + 0.36	0.998	μ g  = 0.0025ω + 0.34	0.997
Lentil	μ c  = 0.0035ω + 0.42	0.921	μ c  = 0.0039ω + 0.39	0.986
μ gl = 0.0025ω + 0.38	1.000	μ gl = 0.0027ω + 0.34	0.959
μ p  = 0.0030ω + 0.36	0.884	μ p  = 0.0033ω + 0.32	0.979
μ g  = 0.0027ω + 0.34	0.991	μ g  = 0.0027ω + 0.32	0.999

Note: μ _c  = coefficient of friction for concrete, μ _gl = coefficient of friction for galvanized iron, μ _p  = coefficient of friction for plywood, and μ _g  = coefficient of friction for glass, ω = moisture content, % (wet basis).

Figure 1 Static coefficient of friction of chickpea at different moisture content.

Figure 2 Kinetic coefficient of friction of chickpea at different moisture content.