Abstract: A vessel (1) contains a rotor disc (23) mounted for rotation around a vertical axis (17) and arranged to bound a processing space (31) disposed above it. The agglomeration and/or the coating of particles are accomplished by moving the particles by the rotation of the rotor disc (23) and by means of a gas, in particular air, passed upwardly through the processing space (31) and by spraying them with a liquid. The torque required for the rotation of the rotor disc (23) is continuously measured by means of a torque measuring member (75) disposed between the rotor disc (23) and the drive device (77) arranged to drive the same. The agglomeration and/or the coating operation is controlled on the basis of the time-dependent variation of the torque and/or of the first derivative of the same, and/or of a variable having relation to the torque and/or its derivative.

Abstract: The system for testing the diffusion behavior of a substance comprises a donor compartment detachably mounted on a holding member of a rotor, rotatably around a vertical axis, said donor compartment being bounded at its bottom by a membrane effective to separate the donor compartment from an acceptor compartment. The membrane comprises a flexible carrier of a bio-compatible, lifeless, light permeable material, on which cells constituting a monocellular layer have been cultivated, for example. By determining the time dependent variation of the quantity of a substance passing through the membrane by diffusion, it is possible to determine the coefficient of diffusion and/or the coefficient of permeability of the membrane and of the cell culture provided thereon. By suitable selection of the cells, conditions may be created that closely resemble those that occur during the absorption of the respective substance through the biophase of a living organism.