Michel, Not to deny the importance of a 'superficial' approach, the importance of this paper probably goes more towards the A-Z type of nanopowder experiments, instead of electrolysis. However, the conclusion about a 'surface effect' is even stronger with these powders than in electrolysis.
For purposes of visualization: The active particle is a comparatively large spheroid of dielectric material (zirconia) fully embedded with much smaller metal 'islands'. The sphere is perhaps 50 microns and the islands are 5 nm. The volumetric ratio of the two components is 10,000:1. There are millions of the metal islands which are either Pd or and alloy of Ni/Pd. It all starts out as a melt-cast amorphous alloy with ~2/3 by mass of zirconium metal, un-oxidized. Each atom of zirconium takes on two additional oxygen atoms during the baking process. Let's see, a metaphor for this particle, if blown up to visible dimensions would be like a basketball fully embedded with grains of table salt, or something like that. There are probably lots of defects and internal vacancies, due to the metal being baked in air to oxidize the zirconium, which is also what forms the nanoparticles by thermal segregation and migration, since they resist oxidization at the temperatures involved. The internal defects are presumably in the size range of Casimir cavities, but none of the SEM images I have seen resolve the details at that geometric level, so it is a guess. Since the "apparent loading ratio" of the large particle is four deuterons for every total atom present in the particle including oxygen, and since the metal can only absorb 1:1 or less on its own, of deuterium, then it would appear the much of the deuterium could be held on the surface of the particle as a thick film of condensed solid, which Arata calls pycnodeuterium. This is only an unofficial opinion and visualization based on integrating all of the papers into a coherent operating view, since none of them go into this kind of presumptive detail. An alternative view is that the internal Casimir cavities hold the bulk of deuterium in a denser form. Some experts like Ed Storms believe that the method, or the conclusion for determining the high loading ratio is flawed. Jones
