Malvern Mastersizer 2000, User Manual

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Chapter 6 Understanding the views
Page 6-10 MAN 0384
Volume-based results
The first, and probably most important, point to remember in interpreting results
is that the fundamental size distribution derived by this technique is volume-based.
This means that when a result indicates, for example, that 11% of the distribution is
in the size category 6.97-7.75 microns, this means the total
volume of all particles
with diameters in this range represents 11% of the total volume of all particles.
It is useful to consider a numerical example to illustrate this point. Suppose, for
simplicity, that a sample consists of only two sizes of particle, 50% by number hav-
ing a diameter of 1 micron and 50% by number a diameter of 10 microns. Assum-
ing that the particles are spherical, the volume of each of the larger particles is 1000
times the volume of one of the smaller ones. Thus, as a volume distribution, the
larger particles represent 99.9% of the total volume.
The graph below illustrates this for a more realistic distribution:
ill 1874
%
30
Particle Diameter (µm.)
0
10
20
0.1 1.0 10.0 100.0 1000.0 10000.0
1
2
1
MAN0384-1.0 Mastersizer 2000.book Page 10 Tuesday, March 20, 2007 8:56 AM