Abstract: A method for verticalizing recorded seismic data, the method including recording first data with a particle motion sensor, wherein the particle motion sensor is located on a streamer, and the particle motion sensor is configured to be insensitive to a direct current, recording second data with a gravity motion sensor, wherein the gravity motion sensor is also located on the stream, and the gravity motion sensor is configured to be sensitive to the direct current and temporally synchronous to the particle motion sensor, selecting a cost function that associates corresponding values of the first data and the second data, determining a misalignment angle from maximizing the cost function, wherein the misalignment angle describes a misalignment between corresponding axes of the particle motion sensor and the gravity motion sensor, and correcting seismic data recorded by the particle motion sensor based on the misalignment angle so that the corrected seismic data is verticalized with regard to gravity.

Abstract: A method for calculating a velocity vp(f, Topt) of a spatially aliased wave that propagates along a cable includes tensioning the cable, wherein plural sensors are distributed along the cable; measuring with the plural sensors a parameter that is associated with vibrations that propagate along the cable; calculating a phase velocity vp(f) of the spatially aliased wave that propagates along the cable, as a function of a time frequency fin a spatial-temporal frequency domain FK; calculating a model-based velocity vp(f, T) of the spatially aliased wave as a function of the time frequency f and a tension T in the cable; and calculating the velocity vp(f, Topt) of the spatially aliased wave using a model-guided regression, which is based on the phase velocity vp(f) and the model-based velocity vp(f, T). The velocity vp(f, Topt) is a function of the temporal frequency f.

Abstract: A method for verticalizing recorded seismic data, the method including recording first data with a particle motion sensor, wherein the particle motion sensor is located on a streamer, and the particle motion sensor is configured to be insensitive to a direct current, recording second data with a gravity motion sensor, wherein the gravity motion sensor is also located on the stream, and the gravity motion sensor is configured to be sensitive to the direct current and temporally synchronous to the particle motion sensor, selecting a cost function that associates corresponding values of the first data and the second data, determining a misalignment angle from maximizing the cost function, wherein the misalignment angle describes a misalignment between corresponding axes of the particle motion sensor and the gravity motion sensor, and correcting seismic data recorded by the particle motion sensor based on the misalignment angle so that the corrected seismic data is verticalized with regard to gravity.

Abstract: A method for calculating a velocity vp(f, Topt) of a spatially aliased wave that propagates along a cable includes tensioning the cable, wherein plural sensors are distributed along the cable; measuring with the plural sensors a parameter that is associated with vibrations that propagate along the cable; calculating a phase velocity vp(f) of the spatially aliased wave that propagates along the cable, as a function of a time frequency fin a spatial-temporal frequency domain FK; calculating a model-based velocity vp(f, T) of the spatially aliased wave as a function of the time frequency f and a tension T in the cable; and calculating the velocity vp(f, Topt) of the spatially aliased wave using a model-guided regression, which is based on the phase velocity vp(f) and the model-based velocity vp(f, T). The velocity vp(f, Topt) is a function of the temporal frequency f.

Abstract: An ingot casting apparatus having an open top ingot moulds hinged to an endless hauling chain of a conveyer. The conveyer is inclined so that the upper descending branch of the endless chain with the ingot moulds placed thereon is inclined to the horizontal at an angle of 30.degree.-60.degree. . Each ingot mould is formed by a bottom, two longitudinal walls and a single transverse wall. The transverse wall of each ingot mould is provided with an opening for passage of the molten metal. With such an arrangement the cavities of the ingot moulds communicate with one another by means of openings provided in the transverse wall of each ingot mould. Mounted above the ingot moulds arranged on the upper descending branch of the endless chain of the conveyer, below the zone where the molten metal is poured into the ingot moulds, is a water-cooled plate adjoining tightly to the top ribs of the walls of the ingot moulds passing under the plate after the molten metal has been poured into them.