A check valve for a fuel pump of a vehicle includes a valve housing adapted to be disposed in an outlet member of the fuel pump and a valve seat formed on the valve housing. The method includes forming a ring within a radius of a wafer. A wire fin can be manufactured by deforming a helical wire member to an elongate, relatively compact shape. Detecting poor data quality may include providing an nn array of covariance values, wherein an element in the ith row and jth column represents a covariance between an ith data quality indicator and a jth data quality indicator. In a method for gasifying biosolids, biosolids are fed into a fluidized bed reactor. Thus, the first electrodes can be easily formed and the image contrast can be improved.