Embodiments of the present invention generally provide methods for forming a silicon nitride layer on a substrate. Reverse current pulses interposed between the forward current pulses consume at least some of the nascent hydrogen and prevent the local pH at the cathode surface from becoming excessively alkaline. A ring gear is fixed to the differential assembly. The data may be stored in a memory associated with the liability assessment program. The estimator outputs parameter estimations for an electrical model of the machine based on the received voltage and rotor position. % saturates and a VI of at least 105 by selectively hydroconverting a raffinate from a solvent extraction zone in a two step hydroconversion zone followed by a hydrofinishing zone, and a lubricating oil basestock produced by said process.