A subject may be interrogated with electromagnetic radiation for producing image data representative of an image of the subject. The passage thickness is precisely controllable and the surfaces move relative to one another so that strong shear is applied to the material between them. The file recovery logic scans each logical sector of the WORM medium’s data surface and identifies a location of a data header sector that corresponds to the unaccessible file. After this, the first masking structure with a view to forming a second masking structure is inverted by applying at least one second auxiliary layer onto the first masking structure. The cut sections are alternately provided at the right and left sides of the layered stirring blades. A sterilization process employing the amperometric gas sensor is disclosed.