Signal Processing and Analysis Applied to Powder Behavior in a Rotating Drum

Abstract

Previous studies of the¯ow of granular materials in a rotating drum have described the observed time sequences of angle of repose or time to avalanche. The time between avalanches approach has been incorporated into a commercially available powder¯ow analysis tool. In the present study, the time to avalanche analysis was complemented with a Fourier Transform power spectrum and phase space analysis of the angle of repose time series and avalanche size variability determination. The avalanche size variability approach was found to most readily differentiate between the¯ow properties of powders across material types. A model was constructed to provide an explanation for the utility of this method.

Composite method to quantify powder flow as a screening method in early tablet or capsule formulation development

“…This event was not a true avalanche but would have been interpreted as such by the instrument. Crowder et al have evaluated the avalanching method of flow characterization and suggest that the data may best be analyzed by a different approach than the time between avalanches [10]. These investigators propose that the variability in the size of powder avalanches represents a more discriminating method of determining flow properties of similar materials and the avalanche size standard deviation provides a quantitatve measure of the uniformity of flow.…”