Abstract: A process is described, and also the system for its embodiment, for the determination of pollution by MTBE in the soil and in the overlying atmosphere. An example is described relating to the monitoring of underground fuel tanks for autotraction containing an oxygenated additive.

Abstract: Toxic components in a gaseous effluent containing toxic organic, chlorinated and non-chlorinated compounds are degraded by a process, comprising: contacting the gaseous effluent containing toxic components with a semiconductor metal oxide; and heating the gaseous effluent in contact with the semiconductor metal oxide to a temperature ranging from 300 to 600° C. while irradiating the gaseous effluent with ultraviolet light having a wave-length ranging from 180 to 400 nm.

Abstract: For sensing gaseous hydrocarbons in a gas mixture, a device consisting of two sensitive elements, one being a reference element, which are heated to different temperatures. The sensors, formed by subjecting films deposited by silk-screen processes to heat treatment at high temperature, are connected to an electronic evaluation circuit.

Abstract: A sensor device for gaseous hydrocarbons includes two semiconductor oxide-based sensitive elements, one of which is a sensitive reference element and the other a sensitive measuring element, this measuring element being covered with a layer of electrically insulating porous material containing a dispersed noble metal. The two sensitive elements are formed by silk-screen processes, are connected to an electronic signal comparison system, and are maintained at different temperatures when in operation. The sensor has improved selectivity in determining gaseous hydrocarbons, in particular methane, even if high concentrations of interfering gases such as ethanol are present.

Abstract: An electrode of nickel oxide intercalated with lithium ions, is obtained by:thermally evaporating, under vacuum, nickel oxide (Ni.sub.2 O.sub.3) and depositing on a conductive glass substrate a film of nickel oxide in which the atomic ratio of nickel to oxygen is comprised within the range of from 0.7:1 to 0.9:1, up to a thickness of the order of 100 nm; andactivating the thin film of nickel oxide by electrochemical intercalation of an amount of lithium ions, which corresponds to a charge level of from 100 to 1,000 C/m.sup.2. An electrochromic window is disclosed, which comprises:(a) an electrode of tungsten oxide (WO.sub.3) on a transparent, conductive glass sheet; and(b) an electrode of nickel oxide activated by electrochemical intercalation of lithium metal, on a transparent, conductive glass sheet;(c) an electrolyte interposed between the (a) electrode and the (b) electrode;wherein the nickel oxide electrode was obtained as said hereinabove.

Abstract: The invention provides photovoltaic cells of new design in which the two semiconductors have lattice parameters which differ by more than 5%. The n-type semiconductor material is constituted by high conductivity CdS doped with indium in a percentage higher than 1%, and the p-type semiconductor material is constituted by Si. The active surface of said cells is equal to or greater than 1.5 cm.sup.2.