A current mirror circuit is described which includes a current input terminal, a current output terminal and a common terminal. A voltage is selectively applied to the smart surface to attract or repel constituents of a fluid mixture, such as oil and water produced from a hydrocarbon well. Polymers can also advantageously be incorporated into the asphalt composition. A movement of the second member in the axial direction is restricted by a restricting portion. It is possible to prevent carbonates, proteins, biofilms and the like from adhering so that cleaning with excellent sterilizing property can be realized. Multiple snapshots can be taken and the delta between snapshots can be determined and sent to a requestor.