A wind turbine generator system can regulate the rotational velocity of the wind turbine within an operation range even when the wind velocity suddenly changes and can perform continuous operation of the wind turbine. The crystal includes at least one dopant element which has a greater concentration toward or near an outermost surface of the crystal than in the center of the crystal. The present method is generally suited for use in transferring cryogenic substances such as during the refueling of liquid natural gas vehicles. A control chamber within the valve body contains pressurized fluid from the pilot supply and is in fluid communication with the flow metering operator. In one described embodiment of the invention, the monitored conditions include software vulnerabilities. The movement created by the counterbalance weight about the axis of rotation maintains the static filling rotational position until a specified volume capacity is achieved.