A layout can identify placement of a plurality of content units of a document across one or more pages with each page representing a display area for displaying the content of the document. Each pixel includes a photoactive region in the semiconductor substrate, a sense node, and a power supply node. The controller then compares such derived values to preselected levels and selectively opens or closes air flow into the cargo unit in order to bring and maintain the desired oxygen and carbon dioxide levels within the unit. To correct the lightness of the original image, the average lightness is compensated when determined to be extremely bright or extremely dark. Furthermore, the invention is related to a corresponding device. Wax product is readily separated from the skeletal iron catalyst in a catalyst settling drum and concentrated catalyst particles in wax slurry are recycled from the settling drum to the slurry reactor, while essentially solid-free wax is recovered as a product.