A density based segmentation method to determine the coordination number of a particulate system

The coordination number is an important parameter for understanding the particulate systems, especially when agglomerated particles are present. However, experimental determination of the coordination number is not trivial. In this study, we describe a 3D classification method, which is based on the revised DBSCAN (Density-Based Spatial Clustering of Applications with Noise) and its application to X-ray micro-tomographic (XMT) images to determine the coordination number distribution. Pellets of micro-crystalline cellulose were used as model particles. The validity of the segmentation was checked by comparing the particle size distribution (PSD) obtained by XMT-DBSCAN with PSD obtained by optical microscopy. The results were found to be in good agreement, demonstrating the suitability of the DBSCAN method. The means and standard deviations of coordination numbers were (8.2 +/- 1.7, n=994 particles), (8.1 +/- 1.5, n=904) and (6.2 +/- 1.2, n=159) for pellets with length based mean sizes of 157, 307 and 437 mu m, respectively. The coordination number distribution was in line with previous finding in mono-sized acrylic beads. (C) 2011 Elsevier Ltd. All rights reserved.