The effect of particle orientation and/or position on two-dimensional shape measurements

Particle shapes were measured based on the random positioned (R) method, the stable positioned (S) method and the stable positioned/constant orientated (S/C) method. The mean values <(<phi>)over bar> and <(<zeta>)over bar> of two shape indices (circularity phi and smoothness zeta), previously defined, were calculated. It was found that smoothness <(<zeta>)over bar> was little affected by shape measuring methods, while circularity <(<phi>)over bar> differed according to methods. By analyzing the change in circularity using model ellipsoidal particles, it was confirmed that the R method could more effectively evaluate particle shapes than can the S method, based on the results of the S/C method.