In a method for controlling an unmanned aerial vehicle equipped with a camera to capture images of a target, the computing device sets coordinates of a target, initial coordinates of the camera, and an initial viewing direction of the camera. While controlling the throughput of electrical current through the electrolysis subassembly, a fuel gas useful for fueling an internal combustion engine is simultaneously generated. Hydrofluoric etching of a silicon surface, for example, is followed by termination of the silicon surface with ligands larger than H or F, particularly hydroxyl, alkoxy or carboxylic tails.