A system is disclosed for conveying articles for processing, the system including a conveyor configured to convey articles to the processing station. The variable-flow fluid source supplies gas at varying rates to the mass flow sensor being calibrated and at proportional rates to a receptacle of known volume. The digestive protein has a half-life at least 1000 times longer than the half-life of a free digestive protein counterpart. This configuration allows the elastic member and the motor to share the load of ribbon feeding and the load of ribbon feed claw switching, reduces the required motor torque, and makes it possible to employ a less powerful, less costly motor. The cam-type apparatus is lockable to allow locking an adjusted position of the cam-type apparatus. The vehicle comprises an internal combustion engine and an adjustable suspension system operable in accordance with first and second ride height settings, said settings being associated with respective first and second vehicle ride heights.