Abstract: It is provided a control system for a gas turbine engine. Therein, at least one piezoelectric, in particular piezoresistive element arranged at a bearing adapted to support a shaft of the gas turbine engine is provided, wherein the piezoelectric element is adapted to provide information indicative for a force acting on the bearing to a processing unit, wherein the processing unit is adapted to determine a thrust force of the gas turbine engine based on the information provided by the piezoelectric element.

Abstract: This invention relates to devices useful in the production of silicon from a melt. According to the invention there is provided an apparatus for the production of silicon from a melt with an indication of a melt spill, the apparatus comprising a crucible for producing a molten material, a susceptor for the crucible, and a melt-spill indicator comprising four leakage sensors. The susceptor for the crucible has four openings, each for accommodating a guiding rod, and each leakage sensor is composed of two electrodes, one of which being bowl-shaped and arranged under a respective guiding rod. The apparatus has a warning device for giving a warning of the melt spill. The apparatus of the invention provides for conditions of crystallization of polycrystalline silicon with any melt leakage adequately detected.