A Study on Moisture Dependent Properties of Barnyard Millet (Echinochloa frumentacea) Grains

Abstract

A vital component in the design of threshers, dehuskers, shellers, and winnowers is the combination of geometrical, frictional, gravimetric, and aerodynamic characteristics of the grain. Therefore, to assess these qualities of barnyard millet grain, experiments were conducted. Samples within a suitable moisture content range of 6.21 to 22.57% (db) were used in the experiments. This was selected based on the moisture content appropriate for the majority of post-harvest operations, which is from of 6 to 24%. The geometrical mean diameter, equivalent mean diameter, arithmetic mean diameter, and square mean diameter increased from 2.05 to 2.24 mm, 2.63 to 2.87 mm, 2.18 to 2.38 mm, and 3.67 to 4.00 mm, respectively, with an increase in moisture content. Similarly, the coefficient of static friction with mild steel, GI sheets, laminated plywood, and glass increased linearly from 0.369 to 0.533, 0.342 to 0.492, 0.288 to 0.301, and 0.314 to 0.363, respectively. Comparing the other three surfaces, it was found that mild steel had the highest coefficient of static friction while laminated plywood had the lowest. Porosity, bulk density, and true density decreased from 0.572 to 0.429, 682.92 to 563.72 kg m-3, and 1318.95 to 1196.81 kg m-3 within the moisture content range, while angle of repose, aspect ratio, sphericity, surface area, volume, 1000 grain weight, coefficient of internal friction, and terminal velocity increased from 23.62° to 40.82°, 65.53 to 66.77, 0.6492 to 0.6569, 13.20 to 15.76 mm2, 4.35 to 6.22 mm3, 3.97 to 5.07 g, 0.556 to 0.863, and 4.42 to 5.23 ms-1.