Fiber-reinforced ceramic composites which comprise at least two layers of a multidirectional woven fiber fabric as reinforcement, with at least 5% of the area of each layer of woven fiber fabric being permeated by matrix material, friction disks comprising these composites as core zone or support zone, a process for producing them and their use as brake disks or clutch disks. The present protection device is in the shape of a hood that covers the entire head, including the face, of a wearer. At least one flat magnetic member has at least one slit that opens in the direction perpendicular to the movement direction of the liquid refrigerant, and the open end of each slit forms a corner to increase heat exchange efficiency. Finally, diagnostic routines are also described. Inside each barrel connector may be disposed center pins. An error signal is generated when the motion quantity measured on the driven side varies from the dynamic model.