The aims of this Lancaster University - Bradford University collaborative project arc to choose suitable particle compositions and ambient conditions, for work on the lack of reproducibility of powder flow behaviour; to measure force curves and investigate energy-dissipative contact processes; to clarify the role of ambient conditions (humidity) and of particle morphology; and to obtain complementary particle flow data. Our intention is thereby to assess how far such single-particle data are able to predict flow behaviour of real value to chemical engineers.
The purpose of the force curve measurements (direct measurements of force as a function of separation) is to charactcrisc the interaction between pairs of individual particles, and between single particles and a flat “wall” surface. The details of particle shape and Gne-scale morphology are revealed by scanning force microscopy (“SFM”, available within the same experimental setup as is used for the force curve measurements). In the previous year’s report we described the results obtained up to 14 November 1997, including the design and construction of a system that allows us to control the relative humidity in a glove box within which the force curves are measured. WC also described how the work at Bradford enabled us to develop improvements to the Warren Spring - Bradford cohesion tester (WSBC) and to standardise the method.