Abstract: A process is disclosed for the preparation of 3-hydroxyalkanals having 3 to 12 carbon atoms, in particular 3 or 4 carbon atoms, by hydration of the underlying 2-alkenals with water in a homogeneous phase in the presence of an acid catalyst. The previously known hydration using mineral acids or carboxylic acids as catalyst results in low volume/time yields and/or low selectivities. These disadvantages can be avoided by using in the present invention, as catalyst, a dissolved acid-base buffer which results in a pH of from 2 to 5 in the reaction mixture; the acid component and corresponding base of which are present in a total quantity of from 0.5 to 40% by weight in the reaction mixture. The preferred buffers composed of a lower monobasic carboxylic acid and a tertiary amine can easily be recycled.

Abstract: An operating arm for a manipulator with length adjustment by telescoping means has a transmission carriage slidably disposed in an outer telescopic tube and a number of concentric tubes are rotatably supported in the center of the transmission carriage for transmitting motion for various functions of the operating arm by means of bearings which are supported coaxially and on top of each other on a roller housing rotatably supported in the transmission carriage. The innermost of the concentric tubes is connected to the roller housing while the others have circumferential spur gear structure in engagement with spur gears and drive shafts extending into the outer tube outside said spur gear structures for operating said other concentric tubes.

Abstract: For the in situ analysis of marine ore concretions, ore samples are aspirated from the sea floor and introduced in a sample container aboard a carrier body travelling underwater along and in the vicinity of the sea floor. While in the sample container, the ore concretions are exposed to radioactive rays for inducing a secondary radiation emanating from the ore concretions. The secondary radiation is measured for determining the quantity of the individual elements contained in the ore concretions.