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Several methods have been developed to measure the friction coefficient of grains and seeds as well as their angle of repose, independently. However, it seems that one single method capable of simultaneous measurement of these two important parameters of grain products is of importance. In this study, simultaneous measurement of brown rice grain friction coefficient and angle of repose is performed by using rotating cylinders method. The effects of rotational speed, cylinder diameter and filling degree on rice grains, also lower and higher angle of repose along with their friction properties were considered. Results showed that proper speed for reaching slumping and rolling motions depends on cylinder diameter and filling degree varying from 0.5 to 9.7 rpm and 2 to 34.6 rpm, respectively. An insignificant difference in the range of 1° to 4° was observed between lower and upper angles of repose which indicates the reliability of the proposed method to determine the dynamic angle of repose. Results also revealed that rotational speed of cylinders did not significantly affect the lower and upper angles of repose; however, they were not affected by filling degree. Finally, the friction coefficient of rice grains was affected by cylinder diameter and filling degree. The findings of this study may be applied in the design and mathematical modeling of grains' motions in rotary dryers, mixers, and silos. [ABSTRACT FROM AUTHOR]

Information on physical properties of virgin olive fruit, especially those grown in Iran,arenot available in literatures. Some physical properties of Mari variety of virgin olive fruits, namely: dimensional properties (length, width, thickness, arithmetic mean diameter, geometric mean diameter, sphericity, volume of the fruit, surface area and projected area), gravimetric properties (unit mass of fruit, 1,000 fruit mass, bulk density, true density and porosity), frictional properties (angle of repose and coefficient of friction), modeling dimensional properties and mass (using normal distribution) were studied. Also sphericity, volume, surface area and projected area were calculated using different theoretical equations. Length, width and thickness of fruits ranged from 18.46 mm to 27.63 mm, 15.80 mm to 21.99 mm and 14.77 mm to 20.33 mm, respectively. Bulk density of fruits increased from 590.78 kg m-3 to 646.51 kg m-3 as the volume container increased from 500 mL to 2,000 mL and true density of 1,059.14 kg m-3 were obtained. The highest value forangle of repose and coefficient of friction amongplywood, rubber, iron and galvanized surfaceswererecorded for iron surface and the lowest value was recorded for galvanized surface. [ABSTRACT FROM AUTHOR]