Hi， 

I hope the following papers are helpful to you.

[1] G.B. Basim, M. Khalili, Particle size analysis on wide size distribution powders; effect of sampling and characterization technique, Adv. Powder Technol., 26 (2015) 200-207. [2] A. Maiti, D. Chakravarty, K. Biswas, A. Halder, Development of a mass model in estimating weight-wise particle size distribution using digital image processing, International Journal of Mining Science and Technology, 27 (2017) 435-443.

Best ,

Fangkun Zhang

Hi Hasan

I hope that the following points be useful:

1. The reproducibility in measured PSD does not like other variables like pressure, Temperature, etc. Different particle size analysis of a standard sample does not exactly match with each other.

2. Sampling should be done in such a manner that it well represents the particle population. In other words, the sampling should be representative.

3. The population of particles in your vessel may differ with time at a specific point. So two succeeding samples from a location may not represents a population.

Please provide more information (method or device used). The different mean value could be related to a wide range of factors.