A mechanical device includes a prime mover, and a number of rotating masses. They may also be used to as a base for make-up, or as a skin care cream to be applied on the body or face. In response to the request, the system sends an encrypted file key for the encrypted file from the file system to a tamper-resistant module. The processor compares the temperature value with a pre-stored temperature threshold. The displacement of the compressor is controlled, such that discharge chamber pressure does not act on the valve body in the opening and closing direction, and pressures acting on the opposite ends of the valve body are maintained at the same level.