Particle size, statistics cumulative distribution

When a distribufion of particle sizes which must be collected is present, the aclual size distribution must be converted to a mass distribution by aerodynamic size. Frequently the distribution can be represented or approximated by a log-normal distribution (a straight line on a log-log plot of cumulative mass percent of particles versus diameter) wmich can be characterized by the mass median particle diameter dp5o and the standard statistical deviation of particles from the median [Pg.1428]

Compared to other methods, TEM is more reliable, accurate and intuitive. Meanwhile it can observe two-dimensional and three-dimensional forms of the particles. However, it only observes the particles in limited range, so it does not have statistical meaning. Based on centrifugal subsidency method, the particle size analyzer can get all kinds of the particles and the differential and cumulative diameter distribution curves of them. In order to dominate or avoid the particles agglomerate, the key is the suspension method in the test. In summary, the three methods are compensated for each other. 

If the statistical fluctuations discussed above, the human factor introduced by the technician doing the work, as well as the differences in presentation and interpretation of data by various test methods are all taken into consideration, it seems extremely difficult to obtain reliable and reproducible results. This conjecture was proved some time ago with a very interesting, but also very shocking, diagram. Figure 23.1 shows twenty-one (21) particle size distribution curves in a probability log diagram. The cumulative percent undersize is plotted versus the measured particle size in micrometers. 

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