The invention is directed to a method for producing an oxygenated biochar material possessing a cation-exchanging property, wherein a biochar source is reacted with one or more oxygenating compounds in such a manner that the biochar source homogeneously acquires oxygen-containing cation-exchanging groups in an incomplete combustion process. The shape of such a wheel may be monitored to detect any such out of roundness, while the wheel is rolling, by measuring how far the flange of the wheel projects below the upper surface of the rail. The adhesion of the insoluble substances to the resist film and the substrate can also be prevented or inhibited by supplying an acid liquid to a liquid on the substrate, or controlling a pH value of the liquid on the substrate to control an absolute value of the zeta potential of the insoluble substances. These switches are designed such that they are in each case interrupted when an energy cell is inserted. In another implementation, a carrier web carries lamination pieces. The input member, the output member, and the first rotating electrical machine are respectively connected to different rotational elements of the differential gear device.