Abstract: A method and a device for the ultrasonic testing of a workpiece having an uneven surface is provided. An ultrasonic test head containing a multiplicity of transducer elements arranged rigidly in a linear array, is acoustically coupled to a workpiece. The ultrasonic test head can be driven in a time-delayed manner with a delay time predetermined for each transducer element. The propagation time of an ultrasonic signal transmitted by an individual transducer element and reflected from the surface and received by this transducer element is measured for a number of the transducer elements and is used for correcting the delay times. The transducer elements are subsequently driven with these corrected delay times.

Abstract: In a method and a device for the ultrasonic testing of a workpiece (2) having an uneven surface (13, 13b) with an ultrasonic test head (10), acoustically coupled to the workpiece (2), which contains a multiplicity of transducer elements (201 to 20n) arranged rigidly in a linear array, which can be driven in a time-delayed manner with a delay time predetermined for each transducer element (201 to 20n), the propagation time of an ultrasonic signal transmitted by an individual transducer element (201 to 20n) and reflected from the surface (13) and received by this transducer element (201 to 20n) is measured for a number of the transducer elements (201 to 20n) and is used for correcting the delay times, and the transducer elements (201 to 20n) are subsequently driven with these corrected delay times.

Abstract: A process for treating mixed plastics waste that comprises macromolecular polymers and low molecular weight polymers is described. The process includes the steps of: introducing the mixed plastics waste into an organic solvent to produce a suspension, the solvent being one in which at least one of the macromolecular polymers is soluble at a specific temperature; maintaining the suspension at a normal pressure and at an operating temperature at which none of the macromolecular polymers dissolve; extracting the low molecular weight polymers from the mixed plastics waste to produce a solution containing dissolved low molecular weight polymers and an extracted mixed plastics waste; and removing the extracted mixed plastics waste.

Abstract: An ultrasonic test head for ultrasonically testing flaws in a workpiece includes a common housing. An ultrasonic transducer configuration is disposed in the common housing. At least one ultrasonic transducer array is disposed in the common housing for operation in a pulse echo mode for transverse waves propagating in a workpiece. The ultrasonic transducer configuration includes at least two acoustically separate ultrasonic transducers to be operated in a transmit/receive mode for longitudinal waves propagating near a surface in the workpiece. In a method for operating the ultrasonic test head, each ultrasonic transducer array or arrays is operated in a transmit/receive mode.

Abstract: A process and an apparatus for strand-casting near to final size cast formats from non-ferrous metals for the purpose of further cold working, especially strips, bars or tubes of copper or copper alloys. The process includes continuously casting the melt in a vertical mold to form a vertical strand, withdrawing the solidified strand from the mold in a centrally guided manner and directly threading into a surface treatment machine, removing the surface of the strand, laterally cutting the surface-finished strand in a predetermined manner, and removing the cut strand pieces from the machine. The machine for carrying out the process has a base frame which is connected to a foundation and on which a withdrawal device, a surface treatment unit, a cross-cutting device, and a conveying device are provided in line.

Abstract: The invention is directed to a device for the horizontal continuous casting of metals having a holding furnace with a horizontally extending outlet conduit arranged in a side wall of the holding furnace, a graphite mold associated with the outlet conduit, and a cooling structure which encloses the mold and is flanged to a casing of the holding furnace. In order to provide a uniform flow of metal in the inlet region of the mold, a flow restricting structure is arranged inside the outlet conduit of the holding furnace. The restricting member is made of refractory material and defined with an interior surface of the outlet conduit a melt passage. The restricting structure is dimensioned such that the cross-sectional profile or area of the melt passage is smaller than the cross-sectional surface of the mold cavity.

Abstract: Continuous process for removing unstable components from crude oxymethylene copolymer, which still contains catalysts, monomeric starting materials and unstable components, by treating the copolymer with deactivators, optionally in the presence of auxiliaries, in a pressure zone, and subsequently removing volatile components in a pressure-release zone in the presence or absence of stabilizers, in which process the crude polymer is fully melted in the absence of the deactivators and auxiliaries immediately after completion of the polymerization step, and the deactivators are subsequently incorporated, alone or together with auxiliaries, under pressure into the resultant polymer melt in at least one pressure zone.By this process, degradation is avoided and significantly better properties are obtained.

Abstract: During the recovery of the unreacted propylene from the mother liquor obtained in the polymerization of liquid propylene, the major part of the propylene is evaporated in a first evaporation step at a low temperature and the remaining part is evaporated in a second evaporator at a high temperature. In this way an early agglomerization of the atactic and/or low-molecular weight polymer dissolved in the mother liquor and fouling of the heat exchanger tubes and/or of the column trays is avoided.

Abstract: Contaminated sulfuric acid which may contain water, organic compounds and inorganic salts is converted to almost pure concentrated sulfuric acid by passing the acid through a Pauling plant and distilling the concentrated contaminated acid.Addition of nitric acid improves the decomposition of organic compounds and ammonium salts of the contaminated acid.