Abstract: The present invention relates to novel materials based on silver and tin oxide for the production of electrical contacts as well as the electrical contacts thus produced. According to the invention, these materials contain at least 6% by weight of tin oxide and from 0.02 to 5% by weight of tellurium oxide; the total content by weight of metal oxides, with the exclusion of tellurium oxide, does not exceed 15%, the balance being made up by silver. Application: manufacture of electrical equipment.

Abstract: Dehydrogenation catalyst, wherein the molar ratio between iron oxide providing agent and potassium oxide providing agent calculated as iron: potassium atomic ratio is in the range of from 1.5 to 60, a K.sub.2 Fe.sub.12 O.sub.19 phase is present in an octahedral Fe.sub.3 O.sub.4 matrix, showing crystalline epitaxy between the hexagonal structure of K.sub.2 Fe.sub.12 O.sub.19 and the (111) planes of the Fe.sub.3 O.sub.4 spinel structure, and showing intense X-ray diffraction peaks in the area of from d=12.4 .ANG. to d=1.60 .ANG..Process for the preparation of such catalyst and process for dehydrogenation of optionally substituted alkanes into olefins.

Abstract: Nicotinic derivatives. They have the formula: ##STR1## with R.sup.1, R.sup.2, which are identical or different,=H, alkyl (C.sub.1 -C.sub.18) optionally substituted phenyl, pyridyl;Y=H, hal, alkyl or alkoxy or C.sub.1 -C.sub.4 ; n=integer from 1 to 3.Agricultural fungal compounds.

Abstract: Nicotinic derivatives. They are of the formula ##STR1## with: A=thiazolyl radical, illustrated where appropriate,Z=methylene,m=1 to 4,y=H, hal, alkyl (1-4C), alkoxy (1-4C),n=1 to 3Fungicidal products for agriculture.

Abstract: Nicotinic acid derivatives They are of formula: ##STR1## with: Z=OR, with R=optionally substituted C.sub.1 -C.sub.18 -alkyl, C.sub.2 -C.sub.18 -alkenyl, C.sub.2 -C.sub.5 -alkynyl, phenyl or phenoxy;Y=H, hal, C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy andn=1 to 3.Fungicidal products for agricultural use.

Abstract: A method of continuously manufacturing thin porous conductive strips, the strips including at least one layer based on a substance which contains carbon and a binder, the method comprising the successive steps of:preparing a very dilute aqueous dispersion of carbon or graphite fibers;adding an aqueous binder emulsion to the dispersion;initiating precipitation of a part of the binder onto the fibers;spreading the mixture in the form of a layer (1,2);removing at least some of the water from the mixture (3);drying the mixture (4,5,6,7); andsetting the layer to the required thickness (8) which may be less than a few tens of microns.

Abstract: Element for detecting the presence of combustible gases in a gaseous atmosphere containing at least one oxidizing agent, comprising a microporous support consisting essentially of a mixture of gamma-and/or eta-alumina and refractory fibres, a catalyst layer based on a metal or an oxide of a metal from the family of the platinoids, located on at least a part of the surface of the microporous support, and a filament based on platinum, of which at least a part is wound round the said support.

Abstract: An arrangement for controlling the recirculation of exhaust gases within internal combustion engines, includes a recycling system of conduits connecting the engine exhaust manifold to the main inlet manifold of the carburetion system and having a recirculating valve interposed within such circuit. The obturator of the recirculation valve has a truncated-cone configuration of such design that the increase in the variable area of the opening between the stopper or obturator and its seat is a function of the engine speed and load. In recycling the exhaust gases, the invention serves as an antipollution means for the exhaust gases of internal combustion engines.

Abstract: A method for producing a catalytic carbon deposit on a conductive support mprising admixing (i) a suspension of between 200 and 400 grams per liter of catalytic carbon in a liquid medium, with (ii) a solution of between 20 and 50 grams per liter of polyvinyl chloride in a cyclic ketone solvent, to form an emulsion, depositing said emulsion on said support, and evaporating the liquid components of said emulsion from said support to form a layer of catalytic carbon in a polyvinyl chloride binder.