Abstract: The invention relates to a method for producing a dimensionally stable concrete workpiece characterised in that to produce the concrete workpiece a fully-sealed dimensionally stable form (20) is filled with fresh concrete in a predetermined geometry, during the subsequent and undisrupted hydratation a predetermined temperature distribution of the walls (21, 22) of the form (20) surrounding the hydrated concrete is carried out and the concrete workpiece is shaped at a compressive strength of more than 10 MPa. The maximum size of the fresh concrete has a diameter of less than 20% of the smallest measurement of the shape.

Abstract: The method according to the invention for producing a prestressed concrete workpiece is characterized in that the prestress is created by a heat treatment, wherein the concrete and the reinforcement therefor are selected in such a way that, when cooling the concrete workpiece from an elevated temperature, the heat expansion coefficient of the concrete is less than that of the reinforcement, and in that, during cooling, the concrete and the reinforcement adhere sufficiently strongly to one another if, during cooling, the concrete is hydrated at least to such an extent in order to be able to expand the reinforcement on account of the different heat expansion coefficients, and in that the concrete, together with the reinforcement, is brought to the elevated temperature in such a way that and is hydrated during cooling at least to such an extent that it is prestressed by the reinforcement after cooling.

Abstract: A drilling tool is configured to perform drilling and/or percussive work on materials such as stone, concrete and/or reinforced concrete. The drilling tool has a fastening region and a working region. The working region has a working body and at least one cutting element projecting axially and/or radially in relation to the working body. The at least one cutting element has at least one first cutting edge and at least one second cutting edge. The at least one second cutting edge is configured to serve as a replacement cutting edge and/or as an auxiliary cutting edge, and the at least one second cutting edge is set back, at least partly, in relation to the at least one first cutting edge of the drilling tool, axially along a longitudinal axis of the drilling tool, in a direction towards the fastening region.

Abstract: A bicycle frame (100) includes: a front triangle (110); a rear frame (130) articulated to the front triangle (110); a body (21) associated to the front triangle (110) and mobile with respect thereto; and a bottom bracket (22) rotatably associated to the body (21) about a first rotation axis (B). The rear frame (130) is articulated to the body (21) about a second rotation axis (C) parallel to the first rotation axis (B).

Abstract: The invention relates to an elongated absorber arrangement for a trough collector, which is subjected to concentrated radiation over its length during operation, and which has means for transporting heat-transporting fluid through the absorber arrangement. The absorber arrangement has at least one fluid-free absorber space for concentrated radiation, which has a thermal opening leading into its interior and walls for absorption of the heat incident into it.

Abstract: The invention relates to a trough collector with a primary concentrator, which concentrates solar radiation into a focal line region, with an arrangement for secondary concentration of the solar rays reflected by the primary concentrator, which arrangement concentrates the solar rays further into focal point regions. The arrangement for secondary concentration has a plurality of rows of secondary concentrators which have identical orientation in a row, but have differing orientation from row to row. Further, means are provided in order to keep one of the rows in the operating position and the other rows in a rest position. Thus, a range of the skew angle can be assigned to each of the rows and in the event of the change thereof, another row is brought into operating position.

Abstract: The invention relates to a compressed air energy storage system comprising a pressure accumulator (2) for gas to be stored under pressure, and a heat accumulator (27) for storing the compression heat that has accumulated during charging of the pressure accumulator (2), wherein the heat accumulator (27) is arranged ready for use in an overpressure zone (31). Said arrangement enables a structurally simple heat accumulator to be provided, since said heat accumulator is not loaded by the pressure of the gas passing therethrough.

Abstract: The invention relates to a trough collector comprising a number of secondary concentrators, by which the solar radiation concentrated by the concentrator of the trough collector in a first direction transverse to the length thereof is concentrated in a second direction running along the trough collector, wherein the secondary concentrators each have a first, front reflecting wall and a second, rear reflecting wall which concentrate the radiation in the second direction, and wherein the secondary concentrators are arranged such as to be synchronously pivotable with one another, preferably about a respective pivot axis fixed with respect to the primary concentrator, such that as the position of the sun changes, the secondary concentrators can always be oriented in accordance with the incident radiation.

Abstract: The invention comprises a method and a device for measuring a reflector for radiation during the operation thereof, in which to determine the current reflection properties of the reflector in a number of at least one measurement points provided in the path of the radiation reflected by the reflector, the pattern of predetermined characteristics of the currently reflected radiation is measured and compared with a predetermined reference pattern, wherein the current geometrical properties of the reflector are inferred from the comparison and in the event of undesired geometrical properties, appropriate operational parameters of the reflector are modified. This method is preferably applied in trough collectors for solar power plants, in order to measure flexible concentrators arranged in a pressure cell, during their operation.

Abstract: The invention relates to a trough collector having a focal area and an absorber tube arranged in the focal area, said absorber tube having an insulating area that extends from its outer surface to the inside, enclosing preferably a transport channel that runs through the absorber tube along its length and carries a heat-transporting medium, and is penetrated by at least one thermal opening that extends radially from the outside through the insulating area to the transport channel. According to the invention, the at least one thermal opening comprises a constriction for radiation passing through it, the focal area being located in the constriction.

Abstract: Due to the further concentrators of a second concentrator arrangement in a linear concentrator configured as a trough concentrator, the concentrated radiation is concentrated in focal point areas, with the consequence that higher concentration of the radiation and thus higher temperatures are achievable in the absorber pipe. In order to lower the exponentially increasing heat losses in the absorber pipe (due to the higher temperatures), an absorber arrangement is provided in synergy, comprising rows of individual thermal openings, wherein these rows lie adjacently to each other.

Abstract: Known high-temperature heat storage devices for the storage of heat at a temperature above 100° C. having a container for heat-storing bulk material such as gravel/ceramic spheres have a steel wall which is constructively extremely complex to manufacture for larger heat storage devices or the storage of heat at higher temperatures. According to the invention, the side wall of the heat storage device for its part is supported by a supporting bulk material and is preferably inclined, with the result that the side wall is substantially less stressed and can be made of a non-metal material such as, for example, concrete. Such a heat storage device is simple and inexpensive to manufacture and allows long-term storage of larger amounts of heat at high temperatures.

Abstract: Disclosed is a radiation collector comprising a pressure cell which is subdivided into a first pressure chamber and a second pressure chamber by means of the concentrator. The small pressure difference between the pressure chambers keeps the concentrator operational in a beam-concentrating form and reduces the wear on the reflective layer of the concentrator. The radiation collector further comprises adequately designed means for establishing the desired pressure in the respective pressure chamber, said means making it possible to compensate changes of the pressure chamber volume resulting from wind load, for example.

Abstract: The solar collector according to the invention has a membrane arrangement 41 comprising zones 70, 71, 72 having different spherical curvature in such a manner that their concentrator membrane 42 which is covered with a reflecting layer is optimally approximated to a parabolic shape and therefore has an optimally small focal point or focal line region.

Abstract: The absorber pipe 10 according to the invention features a thermal opening 14, on which means are provided that reduce the radiation 26 emitted outwards from the absorbing surface 13 as a result of its operating temperature to an increasing extent as the operating temperature increases.

Abstract: A trough collector (1) for solar power plants comprises a pressure cell (25) containing an absorber pipe (42) for a heat-carrying fluid and also a secondary concentrator which is likewise arranged in the pressure cell (25). The pressure cell (25) thus can be reduced in height, which eliminates the need for reinforcements in the form of a framework structure for the pressure cell (25), which are otherwise required.

Abstract: The invention relates to a trough collector (1) for a solar power plant, comprising a mount (34) carrying a supporting structure (30), means disposed on the supporting structure (30) for providing heat originating from incident solar radiation, and a pivot device (40) that is fixed to the supporting structure (30) and is used to pivot the supporting structure (30) with respect to the mount (34), wherein the centroidal axis (36) of the supporting structure (30) equipped with the means for providing the heat is located outside the pivot axis of the supporting structure (30), and wherein the pivot device (40) is configured such that the centroidal axis (39) of the fully equipped supporting structure (30) is located in the region of a fixed pivot axis (35). In this way, a cost-effective, and zero-backlash pivot drive for the trough collector is obtained.

Abstract: Disclosed is a radiation collector comprising a pressure cell which is subdivided into a first pressure chamber and a second pressure chamber by means of the concentrator. The small pressure difference between the pressure chambers keeps the concentrator operational in a beam-concentrating form and reduces the wear on the reflective layer of the concentrator. The radiation collector further comprises adequately designed means for establishing the desired pressure in the respective pressure chamber, said means making it possible to compensate changes of the pressure chamber volume resulting from wind load, for example.