Abstract: Material for the production of hydraulic cements or for pozzolanic materials which develop cementatious characteristics after blending with an activator, is treated in an expanded precessive plasma in a plasma reactor of the type in which at least one plasma gun orbits about a vertical axis and is directed obliquely to said axis towards a counter electrode. The material preferably includes at least a proportion of a naturally occurring carbonaceous material of low calorific value, such as colliery spoil, oil shale or oil sand. In such case, as the material emerges from the plasma it is preferably contacted with air to effect combustion of the combustible material. The thermal energy thus released is recovered by suitable instrumentalities and is preferably converted to electrical energy to power the plasma reactor.

Abstract: Apparatus and method are described for preparing a narrow trace of physiological fluid on a substrate from a discrete fluid pool. The trace so produced is substantially identical to traces manually prepared in that they are characterized by distinct macroscopic and microscopic zones. Automatic trace staining apparatus also is provided.

Abstract: A plasma arc furnace in which an expanded plasma column is generated between at least one orbiting electrode moving in a substantially circular path and a stationary electrode. The orbiting electrode is directed towards the orbital axis so as to generate a plasma column having a portion of generally inverted conical shape in the vicinity of the orbiting electrode and feedstock is introduced into the upper end of the plasma column. The orbiting electrode may be directed across the orbital axis whereby the generated plasma column is in the form of two generally conical portions meeting at a common apex.