Abstract: An element for processing solar radiation includes means for processing solar radiation forming a layer of the solar radiation processing element and includes a layer of radiation-emitting material, especially infrared radiation, covering the layer of the processing means. A sun tracker includes at least one processing element and a solar farm includes a series of sun trackers, each comprising a processing element.

Abstract: A compacted material includes magnesium hydride and expanded natural graphite and a method for preparing such a material including the steps which consist in: (i) mixing a magnesium hydride or powdered magnesium with a powdered graphite; and (ii) shaping the mixture by compaction. It also proposes the use of the material for hydrogen storage and a method for hydrogen storage and release from storage including the steps which consist in: (a) introducing the material into a suitable hydrogen tank; (b) placing the material under hydrogen pressure in pressure and temperature conditions that enable the hydrogen to be absorbed by the material; and (c) desorbing the hydrogen from the material in pressure and temperature conditions permitting the desorption of the material.