According to this invention, silicon-based photodetectors using waveguides formed with silicide regions can have high speed and high efficiency for near IR applications. The mixing element has a first flexible body portion having a first end and a second flexible body portion having a second end, the first end and the second end being connected to the rotary shaft. This heat pipe may contain a liquid coolant that has a density greater than a first pre-determined value at room temperature. Alternatively, the piston information can be compared to a reference signal relating to a desired position, velocity, acceleration, andor direction of movement of the piston to produce a control signal, which can be used to adjust the hydraulic fluid flow and provide the desired actuation of the piston. The heat transfer unit transfers radiation energy toward a part of the film tube that is in contact with the pressure roller.