A kernel processor includes a pair of rollers which are controlled such that the spacing between them varies inversely, or such that the contact pressure between them varies directly, in response to varying moisture content of the crop material being processed. These coupling devices are constituted of a tongue and a groove. The composition is predominantly based on the polyethylene component and contains the polyethylene component in an amount of at least 50 percent by weight. A write-through command is sent to a system bus as a function of whether the address of the store data is valid. The local controller is arranged to correlate optical data, received from the optical probe, to selected data and provide signals to the drug delivery module for adjusting the amounts of the drug to be delivered into the subject.