introducing a secondary gas flow to the bed,
using a downward pointing micronozzel in the form of a
high velocity (hundreds of meters per second) microjet.
For example, APF nanopowders expanded up to 50 times
the initial bed height and ABF nanoparticles were
changed to APF type, showing a bed expansion as much
as 5 times the original bed height with the absence of
bubbles.