Influence of Cereal Seed Orientation on External Friction Coefficients

A relationship between friction plate roughness and the external friction angle of wheat kernels

“…In both types of kernels, kernels with external friction angles on friction plates with surface roughness Ra = 1.39 μm and Ra = 3.25 μm formed a homogeneous group. The average values of the angle of external friction ranged from 16.29°to 23.99°(friction coefficients of 0.29 to 0.45), which is consistent with the results reported by Molenda et al, [5] Kram, [30] Karimi et al, [31] Boac et al, [28] Kaliniewicz, [32] Markowski et al [21] and Kaliniewicz et al [13] Similar values of external friction coefficients were determined in seeds of other plant species, including chick peas, [33] lentils, [34] fenugreek, [35] coriander, [36] cowpeas, [37,38] barley, [39] castor beans [40] and psyllium. [41] Correlations between the physical properties of kernels…”

“…Weak correlations between the angle of external friction and the physical properties of wheat kernels were also reported by Kaliniewicz et al [13] in a study of var. Nawra.…”

“…Device for measuring the frictional properties of seeds [13] : 1 -base of inclined plane, 2 -stepper motor, 3 -CPU controller, 4 -computer, 5 -bottom phototube, 6 -friction plate, 7 -top phototube, 8 -seed, 9 -adjustable arm.…”

“…[12,13] Friction plates made of ST3S steel were fixed to an adjustable arm. The geometrical product specifications (GPS) of friction plates were measured with the Diavite DH-5 (Bülach, Switzerland) surface roughness tester.…”

“…The above measurements were performed according to the method described by Kaliniewicz et al [13,14] Kernel mass was determined on the WAA 100/C/2 weighing scale (Radwag Radom, Polska) to the nearest 0.1 mg. The measured parameters were used to determine the following shape factors for each kernel [15,16] :…”