Abstract: A computer implemented method for simulating interactions between relatively movable objects of arbitrary shapes and sizes wherein a space to be modelled is mapped to a grid of cells each of which is a basic spatial element; a first object is mapped to a first set of grid cells representing the shape of the first object and a second object is mapped to a second set of grid cells representing the shape of the second object, movement of at least one of the objects through the modelled space is simulated by mapping the moved object to an updated set of grid cells selected to represent the shape of the moved object after a predetermined stepwise movement of the object, and movements which would result in sets of cells representing different objects including a common cell are precluded. Each basic spatial element may be a pixel or a voxel.

Abstract: A microelectrical resistance tomography system comprising one or more sensors, each sensor including a wafer substrate of electrically insulating material having an aperture bounding a fluid flow path through a tube and a plurality of sensor electrodes on the substrate disposed circumferentially around the aperture so as to contact the fluid.

Abstract: Method and apparatus for obtaining a representation of the distribution of electrical impedance within material contained within a containing wall, comprising providing a plurality of mutually spaced electrodes mounted at spaced locations of the wall, electrically insulated from one another and arranged to be in electrical contact with material contained within the wall, applying between an electrical reference ground and each electrode, separately, an input electrical signal which, while applied to any one of the electrodes, causes respective output electrical signals to be generated between the reference ground and each other one of the electrodes, measuring the output electrical signals and processing the resulting measured data to provide a representation of the distribution, within the said material, of its electrical impedance.