Abstract: Method for producing methane by first heating and mixing an organic substrate to 70.degree. C. and cooling same with fresh substrate to 50.degree.-60.degree. C. in an antechamber, transferring same to a processing chamber in the presence of methane-producing anaerobic microorganisms and therein cultivating the substrate under anaerobic conditions to produce methane.

Abstract: Production of methane from a substrate comprising an organic material, by way of example in a process by means of a culture of anaerobic and preferably thermophile microorganisms, which in a processing chamber (8) is brought into contact with the organic material and in which the generated gas is collected. The substrate is introduced into an ante-chamber (7) for pretreatment which is provided with a heating device (28) with the substrate heated in the ante-chamber to at least the temperature that it is intended to have during the process or preferably to a higher temperature, whereafter it is transported to said processing chamber (8) to be brought into contact with the culture of microorganisms.

Abstract: In a method of manufacturing consecutive pre-tensioned concrete elements, e.g. concrete sleepers, in a long mould bed, reinforcement ropes are tensioned and closure members are placed between different elements. Prior to casting closure members which are so formed that two or more cast elements are joined together via bridges or shoulders projecting outwardly fron the elements and surrounding the reinforcement ropes are placed in the mould bed at predetermined intervals. The string of cast elements is advanced to an element-separating station at one end of the bed where the elements are successively cut by means of a diamond saw or the like. The bridges between the elements are formed in a manner such that the reinforcement ropes are protected and a small, preferably the smallest possible section of concrete between the elements is severed when the elements are separated from the string of elements.