A battery includes a multi-modular unit formed with fuel cells as modules; a channel system having channels into which gaseous fuel and air can be fed to the cells and the fuel that is partially depleted in the cells can be subjected to afterburning; casin...

Liquid with solvent and metal salt is used as sealant applied to the surface of a raw layer. The sealant is thermally converted into metal oxide when the solvent evaporates based on a heat supply after waiting for penetration into capillary spaces.

The rubbing behavior monitoring system sends an ultrasonic signal (US) onto one of the two rubbing bodies (2,3) and determines the rubbing behavior by measurement of the Doppler shift of the echo (ES) using a mixer (61) pumped by the oscillator (9) with lo...