Optical probing of dangling bonds during silicon thin film growth

Podded propellers constitute a major new development in ship design, especially for cruise liners but also increasingly for freight ships. A podded propeller (pod) consists of an electric motor which directly drives the propeller. This motor unit is located inside a gondola that is hanging from a strut. This strut has a rotating connection to the ship. Advantages with respect to conventional propulsion are an increase in fuel efficiency (up to 10%), better manoeuvrability and low vibrations. However, recent service breakdowns have slowed down the market. The availability of highly accurate model-scale measurements may help to discover the causes of failure in these 23 MW devices. The Maritime Research Institute Netherlands (MARIN) provides the maritime industry with performance predictions and design consultancy. Part of this is based on model-scale tests performed in large water basins, so-called ‘towing tanks’. The ability to perform highly accurate model-scale experiments with pods is a major challenge for MARIN. As yet, all model-scale experiments with pods have been performed with electric motors external to the pod, using bevel gears to drive the propeller axis. This set-up limits the geometric modelling flexibility. Also, it introduces vibrations, which make it difficult to measure dynamic loads which are essential for analysing manoeuvring tests. Further, the sixcomponent load balance that measures the propulsive force of the pod-unit does not deliver the