effect of moisture content on physical properties of barley seeds

in this article, the size, dimensions, volume, bulk and particle densities, empyting and filling angles of repose and friction coefficients against different surfaces were evaluated for two varieties of barley, sahra and valfajr, as a function of moisture content in the range of 10.12 to 42.17 (w.b.%). most physical properties of barley varieties were significantly affected by moisture content variation. the length, width, thickness and unit mass of sahra variety increased from 9.88 to 10.16 mm, 3.37 to 3.89 mm, 2.54 to 2.80 mm and 0.048 to 0.074 g, respectively, as the moisture content increased. the respective values for valfajr varied from 8.37 to 8.87 mm, 3.03 to 3.21 mm, 2.21 to 2.37 mm and 0.037 to 0.043 g, respectively. in sahra variety, sphericity, geometric mean diameter, bulk density, particle density and porosity increased from 44.59 to 47.40%; 4.38 to 4.79 mm; 568.10 to 613.68 kg m-3; 1,099.65 to 1,245.72 kg m-3 and 48.34 to 50.74%, respectively. the coefficient of static friction increased linearly against all the tested surfaces as the moisture content increased. in valfajr variety, sphericity increased from 45.79 to 45.89%; geometric mean diameter increased from 3.82 to 4.06 mm; bulk density increased from 579.68 to 608.58 kg m-3; particle density varied from 1,410.82 to 1,230.61 kg m-3; porosity varied from 58.91 to 50.55% and the coefficient of static friction increased linearly against all the tested surfaces as the moisture content increased. the angle of repose for emptying and filling increased linearly as well.