Abstract: A filling level monitoring device for monitoring a filling level of a fluid in a container includes exciter(s), sensor(s), a signal source connected to the exciter(s), a processor, at least one spatial orientation and acceleration sensor, and a filling level indicator. The device uses the signal source and the exciter(s) to couple vibrational loads having multiple frequency components into the container. Sensors measure vibrations in the container after the exciters transmit the vibrational loads into the container. The processor performs spectral analysis of the input signal and of vibration signals from the sensors, comparing these respective spectral functions to extract resonance frequencies of the container, which are based on the spatial orientation of the container.

Abstract: A solid oxide fuel cell stack for an aircraft engine includes ring-shaped fuel cell assemblies of parallel tubular oxide fuel cells circumferentially around a central axis. A first stacking manifold for each fuel cell assembly is in contact with a first side of the individual fuel cell assembly, a second stacking manifold is in contact with a second side of the individual fuel cell assembly, and a central recess for leading an engine shaft through. Each fuel cell includes a tubular anode and tubular cathode, the fuel cell assemblies stacked in an axial direction through pairs of first and second stacking manifolds contacting each other. Each first stacking manifold includes a hydrogen inlet and is connected to first ends of the anodes of the fuel cells. Each second stacking manifold includes a hydrogen and steam outlet and is connected to second ends of the anodes of the fuel cells.

Abstract: A filling level monitoring device for monitoring a filling level of a fluid in a container includes exciter(s), sensor(s), a signal source connected to the exciter(s), a processor, at least one spatial orientation and acceleration sensor, and a filling level indicator. The device uses the signal source and the exciter(s) to couple vibrational loads having multiple frequency components into the container. Sensors measure vibrations in the container after the exciters transmit the vibrational loads into the container. The processor performs spectral analysis of the input signal and of vibration signals from the sensors, comparing these respective spectral functions to extract resonance frequencies of the container, which are based on the spatial orientation of the container.