Improved magnesium diboride superconducting materials and methods of synthesis are disclosed. The algorithms can be wavelet based, higher order statistics based and neural network based. The gradation conversion characteristics can be corrected in the vicinity of a desired density. The semi-flexible mounting tabs deflect during attachment of the airbag module to the steering wheel to provide good fit and finish between an associated decorative airbag cover and the steering wheel. Using the visual indicators, the acceptable range of prices can also be configured and modified by a trader based on the trader’s preferences. A potential correcting electrode is arranged outside the sample and at a position lower than the sample lower surface, and a potential lower than that of the sample is applied.