Spectral analysis of force fluctuations during probe penetration into cohesive powders

• We investigate force fluctuations during probe penetration into cohesive powders consisting of ∼5 μm lactose particles with varying surfaceproperties prepared by spray drying. The results obtained for the more cohesive powders were remarkably similar to those previously reported fororders of magnitude larger noncohesive particles. For the less cohesive powders, the spectral densities were instead found to exhibit two distinctpower-law regions. Furthermore, the spectra were found to be independent of the geometry of the penetrating probe and dimensions of the diecavity. These findings suggest that the response is dominated by particle aggregate or agglomerate movement for the more cohesive powders,whereas the behaviour of the less cohesive ones is consistent with a response dominated by relatively weak force chains, with the fluctuations resulting from the recurring creation and collapse of jammed states being damped for length scales N0.1 mm.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Farmaceutiska vetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Pharmaceutical Sciences (hsv//eng)

Keyword

Granular materials

powders

cohesion

probe penetration

fluctuations

percolation

PHARMACY

FARMACI

Publication and Content Type

ref (subject category)

art (subject category)