چکیده : 

The flow characteristics of a powder system are known to be influenced by particle size distribution, particularly

the content of fine particles, and interparticle forces. This paper reports an investigation that has

identified and quantified links between physical properties, viz size distribution, bulk density and particle

density, and cohesion in compacted beds of powder. An annular shear cell was used in the determination

of the cohesion of cohesive and free-flowing milled lactose powders at low consolidation stresses in the

range 0.31–4.85 kPa and under ambient conditions. Following consideration of the compaction and

shearing processes, it was postulated and confirmed that cohesion could be expressed as a function of

powder surface area per unit volume and dimensionless preconsolidation stress. It was shown that care

is needed in the measurement of surface–volume mean diameter when applying correlations developed

from the experimental data.