Abstract: The present invention concerns an engine comprising at least one working cylinder (1) which has valves (16) and/or nozzles for the feed or injection of fuel and air and for the outlet of exhaust gas and a method of operating such an engine.

Abstract: The present invention concerns a method of utilising the waste heat contained in the exhaust gas of an internal combustion engine, comprising a turbine (20). To provide an apparatus and a method of operating same which directly supplies additional drive energy which otherwise would be lost as waste heat, it is proposed according to the invention that the turbine is an inverse turbine connected downstream of the exhaust gas outlet of the internal combustion engine and comprising at the inlet side an expansion stage (23) and at the outlet side a subsequent compressor (21), wherein the expansion stage and the compressor of the inverse turbine are so designed that the downstream-disposed compressor of the inverse turbine generates at the outlet of the expansion stage (23) a reduced pressure (p1) below the ambient pressure (p0), wherein the outlet (2b) of the compressor (21) is at the level of the ambient pressure and the compressor of the inverse turbine is driven by the turbine.

Abstract: The invention relates to a platelet-shaped pigment having high luster and high covering power or high transparency, consisting of a transparent, inorganic, platelet-shaped matrix which can contain an additional constituent, characterized in that the additional constituent is a soluble or insoluble colorant and in that the matrix is coated at least on one side with one or more thin, transparent or semi-transparent reflective layers of metal oxides or metals to achieve the luster.

Abstract: The invention relates to a platelet-like pigment having high lustre and high covering power or high transparency, consisting of a transparent, inorganic, platelet-like matrix which can contain an additional constituent, characterised in that the additional constituent is a soluble or insoluble colorant and in that the matrix is coated at least on one side with one or more thin, transparent or semi-transparent reflective layers of metal oxides or metals to achieve the lustre.

Abstract: Multilayer interference pigment consisting of plateletlike titanium dioxide as carrier material, coated with alternating layers of metal oxides of low and high refractive index, the difference in the refractive indices being at least 0.1, which is obtainable by solidification and hydrolysis of an aqueous solution of a thermally hydrolyzable titanium compound on a continuous belt, detachment of the resulting coat, coating of the resulting titanium dioxide platelets, with or without drying in between, by a wet method with, alternately, a metal oxide hydrate of high refractive index and a metal oxide hydrate of low refractive index by hydrolysis of the corresponding, water-soluble metal compounds, separation, drying and, if desired, calcining of the material obtained.

Abstract: Multilayer interference pigment consisting of plateletlike titanium dioxide as carrier material, coated with alternating layers of metal oxides of low and high refractive index, the difference in the refractive indices being at least 0.1, which is obtainable by solidification and hydrolysis of an aqueous solution of a thermally hydrolysable titanium compound on a continuous belt, detachment of the resulting coat, coating of the resulting titanium dioxide platelets, with or without drying in between, by a wet method with, alternately, a metal oxide hydrate of high refractive index and a metal oxide hydrate of low refractive index by hydrolysis of the corresponding, water-soluble metal compounds, separation, drying and, if desired, calcining of the material obtained.

Abstract: Colored pearl luster pigment consisting of a core of platelet shaped titanium dioxide and one or more layers of other metal oxides or metal oxide hydrates obtainable by solidifying an aqueous solution of a thermally hydrolyzable titanium compound on a continuous belt, detaching the resulting layer, coating the resulting titanium dioxide platelets, with or without drying in between, with one or more other metal oxides or metal oxide hydrates, for example Fe2O3, Fe3O4, FeOOH or Cr2O3, by a wet method, separating, drying and, if desired, calcining the material obtained.

Abstract: Multilayer interference pigment consisting of plateletlike titanium dioxide as carrier material, coated with alternating layers of metal oxides of low and high refractive index, the difference in the refractive indices being at least 0.1, which is obtainable by solidification and hydrolysis of an aqueous solution of a thermally hydrolysable titanium compound on a continuous belt, detachment of the resulting coat, coating of the resulting titanium dioxide platelets, with or without drying in between, by a wet method with, alternately, a metal oxide hydrate of high refractive index and a metal oxide hydrate of low refractive index by hydrolysis of the corresponding, water-soluble metal compounds, separation, drying and, if desired, calcining of the material obtained.

Abstract: Multilayer interference pigment consisting of a central layer of a transparent or semitransparent material of low refractive index and alternating layers of a metal or of a material of high refractive index and of a material of low refractive index either side of the central layer, the material of low refractive index preferably being magnesium fluoride or acrylate and the metal preferably being aluminium or chromium.

Abstract: Multilayer interference pigment consisting of a central, absorbing layer and alternating layers of a material of low refractive index and of a metal or of a material of high refractive index either side of the central layer, the material of low refractive index preferably being acrylate and the metal being aluminium or chromium. The absorbing layer consists of a coating system which comprises carbon black or color-imparting absorption pigments.

Abstract: Plateletlike, substrate-free titanium dioxide pigment obtainable by solidifying an aqueous solution of a thermally hydrolyzable titanium compound on a continuous belt, detaching the resulting layer, coating the resulting titanium dioxide platelets, with or without drying in between, with further titanium dioxide by a wet method, and separating off, drying and calcining the material obtained.

Abstract: A light-stable cosmetic composition for protection from UV rays having a wavelength of between 280 and 400 nm, which contains at least one tetraalkylquercetin in a cosmetically acceptable oil-based medium, and new tetraalkylquercetins.

Abstract: Water-containing inorganic waste materials, originally in loose form, and which contain water-soluble components capable of reacting with each other are mixed and then compacted at a pressure sufficient to reduce the space, volume between the particles of material, cause the reduced space volume to become filled with water and the reactive components to react.

Abstract: Substrate-free electrically conductive pigment containing 90 to 98% by weight of tin oxide and 1 to 10% by weight of at least one doping substance consisting of an oxide of an element form main group III, IV or V of the Periodic Table with the exception of tin, which pigment is preparable by intimate mixing of tin dioxide with at least one doping substance, followed by calcining of the resulting mixture at 800.degree. to 1,000.degree. C. for 30 to 120 minutes.

Abstract: The invention relates to an implant material which is based on a composite material of calcium phosphate ceramic particles and bioabsorbable polymer, in which the proportion of calcium phosphate ceramic particles is at least 50% by weight and the particles are joined to one another by polymer bridges to give a three-dimensional open-pore structure in which the particle surfaces are covered with polymer to the extent of not more than 50%. This implant material is distinguished by particularly favorable growing-in and healing-in properties.

Abstract: The invention relates to a process and an apparatus for converting metal nitrate or mixed metal nitrate solutions into the corresponding metal oxides in a microwave field. The invention consists in heating, while the feed stream is being metered in, in such a manner that the solvent always evaporates within seconds and the decomposition product is obtained as a porous, sponge-like, purely oxidic material, which can be ground easily to give a powder having particle sizes of 0.5 to about 10 .mu.m. The controlled metering in of the nitrate solution simultaneously makes it possible to control the reaction temperature below the sintering temperature of the powder. The reaction of the nitrate starting solution can take place continuously/batchwise in a reaction flask or continuously in a rotating reaction pipe, which is preferably charged with grinding balls, which possibly exert a reaction-activating effect similar to that exerted very particularly by the metal oxide sponge formed during the reaction.

Abstract: The invention relates to a process for the preparation of a resorptive bone ceramic on the basis of tricalcium phosphate which can be used as a bone replacement material. In the process, natural bone material, freed from the soft tissues, is used as the starting material. The remaining organic substances are removed from this starting material by pyrolysis. The remaining bone material, which consists virtually completely of hydroxyapatite, is subsequently treated with a phosphate carrier and then subjected to a sintering step.

Abstract: According to a process for producing a bone replacement material, natural bones are used as raw material, the soft parts of the bones are removed, as well as any residual organic substances, and the remaining osseous substance is finally sintered at temperatures between 1100 degrees and 1500 degrees Celcius. In order to simplify such a process and to ensure a more gentle processing of the inorganic bone matrix, the bones are dried at an increased temperature, maximum 550 degrees Celcius, with a reduced air supply or in a reducing atmosphere, then the temperature of the bones is increased during the following step up to 750 degrees to 800 degrees Celcius, with an increased air supply, and finally the bones are sintered.

Abstract: The invention relates to a process and a device for obtaining pure oxygen using a gastight membrane which can conduct both electrons and oxygen ions.