The invention relates to a field emission display constructed using an array of fibers and an orthogonal array of emitter electrodes. An image is reconstructed and displayed, and in the displayed image a region of interest covering the heated area is automatically demarcated according to a predetermined size of said region of interest that covers and is larger than the heated area. The composition of the suspension or solution can selectively include at least one kind of transition metal oxide ions or a precursor of transition metal oxide. Methods are also provided to ensure proper functioning of the emptying of particular collection systems employing hoppers that discharge particulate into feeders.