Abstract: A method of manufacturing a sulfide-based ceramic element, such as a transparent infrared optical element, comprises the steps of: synthesizing a sulfide powder; and sintering the powder to form the ceramic element; wherein the step of synthesizing the sulfide powder is performed by combustion in an aqueous solution, the solution comprising water as its only solvent, or containing water as its main solvent and at most 10%, and preferably at most 1% of the overall solvent mass, of one or more combustible solvents. The sulfide powder may be chosen, in particular, among ZnS, BaLa2S4, CaLa2S4.

Abstract: A sensor responds sensitively to low concentrations of carbon dioxide in an atmosphere of air. Carbonates formed at the surface of preferred oxides can be decomposed by raising the temperature, thus reforming the original oxide. A CO2 sensor operating according to this principle may be cycled between the temperature at which the surface carbonate is decomposed and the temperature at which the surface carbonate is formed from atmospheric carbon dioxide. The present invention relates to sensors and more particularly to sensors suitable for use in gaseous mixtures containing carbon dioxide.