Determining physical properties of Jatropha Curcas L. grains

Abstract

The objective of this study was to determine the physical properties of Jatropha curcas grains, such as: size, shape, density and porosity, and to determine the terminal velocity, comparing the results with those calculated from mathematical models available in the literature. To perform the experimental analysis, samples with different moisture contents, between 4 and 25% (wb), were selected. To determine the size and shape of the grains, sphericity and roundness characteristics were used, and it was found that both stay approximately constant, despite different moisture content. For specific weight and porosity, results show that the porosity is directly proportional to the moisture content until the point where interaction between the moisture content and volumetric contraction causes the specific weight to increase again, thus decreasing porosity. It was also found that the equation used for calculating the terminal velocity is in agreement with the results obtained experimentally. Furthermore, the results also show that the terminal velocity for the Jatropha grains is directly proportional to its moisture content.