A fiber processing machine includes a sliver drafting unit which has first and second adjoining roll assemblies each defining a nip through which a sliver runs in a sliver advancing direction. The sensing devices include a substrate, an oxide disposed on the substrate, a nitride disposed on the oxide, an electrically conductive structure disposed on the oxide layer, and an electrode disposed on the oxide layer and electrically coupled to the electrically conductive structure. 1% to 10% by weight of a neutralizing agent; 0.