Effect of Moisture Content and Types of Structural Surfaces on coefficient of Friction of two Nigerian Food Grains....
The knowledge of coefficient of friction of food grains on various structural surfaces is important in analysis and design of post harvest handling, food processing and storage equipment. Measurements were made to determine the coefficient of friction of two local food grains (sorghum and millet). Effects of various structural surfaces and different moisture content levels on the measured parameters (coefficient of friction) were determined. Both factors examined had a high significant effect (P< 0.01) on the coefficient of friction of the grains. The coefficient of friction obtained for sorghum ranged from 0.43 ± 0.05 to 0.71± 0.12 over a moisture content range of 22.9 to 33.3 % (wb). That of millet ranged from 0.19 ± 0.04 to 0.46 ± 0.08 over a moisture range of 21 % to 34.7 % (wb). For sorghum, the highest values of coefficient of friction were obtained with concrete followed by steel, wood and plastic. Coefficient of friction for the grains increased linearly with increase in moisture content. For millet, the highest values of coefficient of friction were obtained with concrete surfaces, followed by steel, plastic and wood.
Keywords: Coefficient of friction, structural surfaces, grain handling, sorghum, millet, Nigeria.