What is D90
D90 is particle size distribution D90, it represents the particle diameter corresponding to 90% cumulative (from 0 to 100%) undersize particle size distribution. In other words, if particle size D90 is 117.8um, we can say 90% of the particles in the tested sample are smaller than 117.8 micrometer, or the percentage of particles smaller than 117.8 micrometer is 90%. D90 is a typical point in particle size distribution analysis. D90 is also divided into Dv90, Dw90 and Dn90. Dv90 means volume D90, whereas Dw90 is mass D90 and Dn90 is number D90
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Particle size D90 https://www.aimsizer.com