Abstract: The system for damping oscillations in a structure according to the invention provides two masses that can be controlled to rotate at the frequency of oscillation of the structure and in opposite directions about axes of rotation transverse to the direction of the oscillations. The masses have individually controllable moments of inertia, and when their moments of inertia are equal a harmonic linear force is generated. The phases of the rotating masses can be individually controlled whereby the direction of the resulting harmonic linear force can be controlled. The moments of inertia can be controlled by shifting their centres of gravity relative to the respective axes of rotation.

Abstract: There is described a device for fastening in a bone, preferably the cranial bone. The device is usable for continual supervision without sterile conditions and without need for full anaesthesia. The device comprises a self-cutting screw which by means of a tool is placed in a boring that previously has been formed in the bone. The screw has an inner hollow space in which there is located a signal transducer, and at that end facing inwards towards the cranial cavity, the screw will be covered by signal penetrable membrane. When the screw is in its proper place, the “observation aperture” which is formed will have been closed, and, in practise, it appears that there is no risk of infections.