A Typical PSD Calculation

Let us suppose that we have a partiele counting instrument which sorts and counts the number of particles at a given particle size. There are several commercial instruments available including the Coulter Counter and those based on Laser-Refraetometry . We will use one of these to obtain the following particle data, given as follows  

Having listed these data, our next step is to calculate the average size  

Measuring particle size and growing single crystals 

For pcirticles less than 2.2 n, we have 2 particles. At 3.0 p, we have 4 particles. Therefore, in the range 2.2 - 3.0 p, we have two (2) particles whose average size is 2.6 p. In the range 3.0 - 5.0 p, we have four (4) particles whose average size is 4.0 p. We have a total of 2000 particles that we have measured and we can calculate the percent (%) of total counts for each size range. 

We therefore continue to calculate An as shown in the above table. Note that the same methods of arranging size data are used regardless of whether we use screens to separate the particles into size fractions or whether we use PSD instrumentation to do so. This gives the following log-normal PSD plot, as shown in the following  

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