Abstract: Alkynes, dienes, alkenynes and/or polyenes in an olefin-containing hydrocarbon stream are selectively hydrogenated catalytically in the gas phase in at least two reaction zones connected in series without introduction of part of this hydrocarbon stream between the penultimate reaction zone and the last reaction zone, wherein the hydrogen content in the reaction gas mixture upstream of the penultimate reaction zone and the degree of conversion in the penultimate reaction zone are set so that the reaction gas mixture contains at least 0.7% by volume of hydrogen at the outlet of the penultimate reaction zone.

Abstract: The invention relates to the production of forms or similar from foamed metal based on aluminum or other metals. Semi-finished product bodies or similar consisting of a foamable semi-finished product material obtained by compacting a mixture of at least one matrix metal powder and at least one expanding agent which releases a foaming gas are placed into a foaming mould or similar where they are geometrically arranged in the desired manner and then heated to a temperature in the range of melting temperature of the matrix metal. Once the mould has been filled, the foaming process is concluded and the resulting foamed metal forms are shaped out.

Abstract: The invention relates to the production of forms or similar from foamed metal based on aluminum or other metals. Semi-finished product bodies or similar consisting of a foamable semi-finished product material obtained by compacting a mixture of at least one matrix metal powder and at least one expanding agent which releases a foaming gas are placed into a foaming mould or similar where they are geometrically arranged in the desired manner and then heated to a temperature in the range of melting temperature of the matrix metal. Once the mould has been filled, the foaming process is concluded and the resulting foamed metal forms are shaped out.

Abstract: A process for the production of foamable elements, in which a metal powder is mixed with a foaming agent powder, the powder mixture is brought to an elevated temperature in a receiver and is extruded through a die, so that the extruded part can be subsequently foamed by decomposition of the foaming agent powder by heating of the extruded part and then cooled to yield a finished foam element. The powder mixture is continuously introduced into a channel, leading to the die, which has a moving wall component by which the powder mixture is transported in the channel by friction with precompacting and is extruded through the die. The speed of the wall component is selected so that the heating necessary for the precompacting comes from heat generated in the transport operation.

Abstract: A hydrometallurgical process for enrichment of gold, platinum and palladium from copper electrolysis anode sludge, and simultaneously recovery of selenium, in which the sludge is treated with Cl.sub.2 /HCl to transform the selenium of a hexavelent state and precipitate out silver chloride. The filtrate is then subjected to selective reduction of precipitate the noble metals and the resulting filtrate is chlorinated and a further reduction is effected to precipitate the metallic selenium.

Abstract: A method for the removal of impurities from copper cathodes withdrawn from a copper electrorefining bath in which the cathodes are subjected to ultrasonic vibrations in the KHz. range in heated water which is circulated or subjected to jets and under conditions in which cavitation bubbles can develop along the surfaces of the cathode.

Abstract: A fuel injection system for an internal combustion engine includes an electronic fuel controller which accepts signals representative of the air flow rate through the engine's induction tube as well as data relating to rpm and other parameters. The air flow rate data is derived from an electrically heated wire, located in the induction tube, which is connected in one branch of a bridge circuit. Changes in the air flow rate result in changes of heat transfer and hence of the temperature of the heated wire whose impedence changes accordingly. A control loop senses the imbalance of the currents in the two branches and acts to restore equilibrium, e.g. by increasing the total bridge current until a higher heat loss from the wire has been compensated. The increased bridge current is provided by periodic current pulses delivered by transistors under the control of a multivibrator. The multivibrator is triggered at a frequency which is a function of the imbalance signal voltage.