A prime mover has an internal combustion engine and a motor generator. The entity charged with authentication maintains a list of previously used bit patterns, extracted from a portion of the authentication message connected to the random component. The valve acts to open and close the air flow passageway through the device and is mounted over the air flow vents of the container. The presence of silicon-carbon micro crystals in each silicon-germanium-carbon layer reduces the formation of, and the propagation of threading dislocations in overlying silicon-germanium layers, therefore also reducing extension of these defects into an overlying silicon layer, wherein the tensile strained silicon layer will be used to accommodate a subsequent device structure. The aircraft is contemplated to be a drone. An accelerometer device is fixedly joined to the hollow body and which is adapted to provide instantaneous measurements of at least one acceleration component of the terrestrial gravity in at least one fixed direction which is fixed relative to the hollow body, and a processing unit for processing the acceleration measurements supplied by the accelerometer device.