A fuel cell stack includes a stack body formed by stacking a plurality of solid oxide fuel cells in a stacking direction. The phantom is compatible with X-ray, ultrasound and magnetic resonance imaging techniques. Controls include the specification of priorities and preferences as well as the modification of priorities and preferences that have been learned from training sets via machine learning methods. The shaft forms a passage that is configured to receive an associated mating contact held within the cavity for establishing an electrical connection. Preferably the coupling has reels associated with the valve and connected by a flexible cord.