Effect of moisture content on engineering properties of urdbean (Vigna mungo)

Some engineering properties of urdbean were determined by increasing its moisture content (from 10 to 14%). The average length, width and thickness of the 20 urdbean seeds varied from 3.61 to 4.10 mm, 2.75 to 3.11 mm and 3.04 to 3.44 mm, respectively as the moisture content increased. The mean value of sphericity decreased from 0.86 to 0.81 with decrease in bulk density. True density was increased from 1013.43 to 1231.03 kg m⁻³ with increased moisture content. Also the porosity of urdbean seeds was increased linearly from 30.68 to 44.02 per cent and an angle of repose was found increased from 27.82° to 30.38°. The coefficient of friction was observed to be increased from 0.34 to 0.42, 0.32 to 0.38 and 0.30 to 0.37 in the case of plywood, cardboard and mild steel surfaces, respectively. The hardness of urdbean decreased from 5.98 to 3.75 kgf with increase in moisture content from 10 to 14%.