The evaluation of mixedness by run length between sought particles.
Haruo Watanabe, Eiji Obata · Journal of the Society of Powder Technology Japan · 1986
The probability density functions of run length between sought particles and its mean in the samples of a random binary mixture are expressed by the geometric and normal distribution, respectively, which were confirmed by simulation. One can thus regard a particle mixture to have the expected proportion of sought particles before mixing when the observed run length or its mean in each sample falls within the 95% confidence limits of the distribution. With regard to the theory, mixing indices using run lengths were investigated to test the statistical randomness of a binary particle mixture.Experimental results showed that the mean run length decreased as the number of helices increased in the motionless mixer, and 12 helices were needed to obtain a satisfactory random mixture when the number proportions of sought particle are 0.2 and 0.4. However, the run length alone was not suitable as a mixing index because the maximum value in each sample often exceeded the upper confidence limit.