Abstract: The invention proposes a method of operating a rotary compressor (1) with twisted rotors (10, 20) for compressing gaseous media, in which a gas-dynamic pulse is generated in the delivery chamber (4) flowed through in each case from an inflow side (4?) to an outlet side (4?) in the longitudinal direction of the delivery chamber by rapid separation from an area of enlarged volume (V), and a closing time (tS) from separation of the relevant delivery chamber (4) flowed through in the longitudinal direction of the delivery chamber from the area of enlarged volume (V) to closure of the relevant delivery chamber (4) on the inflow side (4?) is such that the filling level of the delivery chamber (4) is increased by pulse charging.

Abstract: A method for stimulating growth in biological tissue or sprouts, an apparatus and a use thereof employs fluctuating magnetic fields. The apparatus includes a pulse generator and a plurality of coils in which pulsed currents will cause fluctuating magnetic fields in a predetermined region holding the material to be stimulated. The fluctuating magnetic fields will induce an electric field in the material. An enhanced effect has been detected in the regions where the electric fields are largest. The coils include a number of pairs of coils having, during a given pulse, magnetic fields in opposite directions in order to provide field gradients in the cells, micro organisms or tissue. Selecting a suitable number, size and positioning of coils will provide a homogeneous electric field in the predetermined region, which does not have any undesirable peaked maxima.

Abstract: In a roots compressor for compressing of gaseous media, in which alternately in the delivery chambers formed in each case from the respective Roots pistons and the associated delivery space walls of the cylinder and the end side plates, after closure of the suction side, delivery medium is fed in from the delivery side via channels in the cylinder surfaces, the base surface and the side surfaces of the channels are incorporated at least partially in an insert which is releasably secured in a recess in the cylinder wall.