The present invention relates to a method for improving the operation of a grain cleaning system in a combine harvester characterized in that the method comprises the step of adjusting the position of the upper sieve in the grain cleaning system upon registering a deviance from a threshold value for crop material load on the upper sieve such that the material return flow is adjusted. The prosthesis stem has an open sided central bore. MTJ performance may be further improved by selecting a composite free layer having a FeNiFeHf or CoFeFeNiFeHf configuration where the NiFeHf layer adjoins a capping layer in a bottom spin valve configuration. In another embodiment, the nanoparticles have neither a spherical nor pseudo-spherical shape. The mounting members extend respectively from the first sidewalls toward the circuit board corresponding to the mounting holes of the circuit board.