A centrifugal blower includes a rotation shaft, an impeller, a casing, and a deflection portion. The impeller rotates about the rotation shaft to draw an air therein in an axial direction of the rotation shaft and discharge the air outward in a radial direction of the rotation shaft. The impeller includes a plurality of blades and a side panel having an annular shape and connecting the plurality of blades in the axial direction. The casing accommodates the impeller and includes an air intake portion adjacent to the side panel. The air intake portion has a bell mouth shape to have a rim portion that defines an opening through which the drawn air is guided to an inside of the impeller. The deflection portion deflects an airflow along the rim portion of the air intake portion toward the side panel.

A voltage application device of an embodiment applies a voltage between a first and second electrode disposed separately from each other in an airflow generation device, which is disposed on a rotation blade of a rotation apparatus, in which a rotation shaft of the rotation blade is held rotatably by a holding part. In the voltage application device of the embodiment, a voltage output unit outputs a voltage. Then, a sliding type transmission unit having electrodes disposed respectively on the rotation blade side and the holding part side of the rotation shaft transmits a voltage outputted from the voltage output unit from the holding part side to the rotation blade side. Then, a transformation unit disposed on the rotation blade side increases the voltage transmitted by the sliding type transmission unit and outputs the voltage to the airflow generation device.

A method for manufacturing a valve assembly includes the steps of: providing one or more nickel-based superalloy components of the valve assembly, wherein the one or more components are designed to be subjected to operating environments including temperatures of about 760 C., +/about 30 C.; aluminizing the one or more components using an aluminizing process, wherein the aluminizing process causes inter-diffusion between the nickel-based superalloy and aluminum as well as forms an aluminum-rich surface layer on the one or more components, thereby forming one or more aluminized components; and subjecting the one or more aluminized components to a plasma electrolytic oxidation process to convert the aluminum rich surface layer into a hard, wear-resistant, and oxidation-resistant aluminum oxide coating layer, wherein the hardness, wear-resistance, and oxidation-resistance of the aluminum oxide coating layer is maintained in the operating environments including temperatures of about 760 C., +/about 30 C.