SOME PHYSICAL an‎d MECHANICAL PROPERTIES OF WHEAT GRAIN

Physical properties often required for developing the machines for cleaning of grain. Physical properties of wheat varieties (Sakha93) were determined and compared for moisture content 9, 11, 13 and 15% w.b. The average length, width and thickness were 7.46, 3.37 and 2.66 mm at a moisture content of 9% w.b., respectively. Studies on wheat grain showed that the thousand-kernel mass increased from 48.596 to 55.206g when the moisture content increased from 9 to 15%. The geometric, equivalent and arithmetic mean diameter at a moisture content of 9% were 4.06, 4.08 and 4.5mm. The average mass of one grain, volume and surface area were 0.048g, 35.49 mm3 and 43.87 mm2. Area of flat and transverse surface was 19.74 and 7.04 mm2. Sphericity and index-k were 54.41% and 2.49. Bulk density decreased from 660 to 589.8 kg m-3, when increasing the moisture content from 9 to 15% .True density decreased from 1244.6 to 1210.8 kg m-3, when increasing the moisture content from 9 to 15%.Angle of repose varied from 16.8 to 21.6º when the moisture content increased from 9 to 15% .The static friction coefficient of wheat increased linearly against surfaces of four structural materials, namely, wood (0.379 – 0.399), galvanized iron (0.345 – 0.364), formica (0.306 – 0.344) and glass (0.299 – 0.335) as the moisture content increased from 9 to 15%.