The wear resistance of a steel shaft is to be improved by hardening its surface by increasing the nitrogen (N) content within an outer surface layer as a result of nitrogen diffusion into the steel; the nitrogen is to be supplied from an external N-rich gas at an elevated and constant temperature. The initial N content of the steel is 0.0025 wt%, whereas the surface concentration is to be maintained at 0.45 wt%. For this treatment to be effective, a N content of 0.12 wt% must be established at a position 0.45 mm below the surface. (a) Will this process be a steady state or non-state process? Why?