New plane-grating monochromators for third generation synchrotron radiation light sources

For the electron storage ring BESSY II a new type of plane-grating monochromators working with collimated light is proposed. The operation with collimated light is a well-known optical technique, which enables us to keep the focusing condition fulfilled automatically for all photon energies. The additional degree of freedom gained allows the monochromator to comply with the most different needs of the users. An additional feature of the design is the further extension of the already widely accessible energy range of a PGM towards lower photon energies.

The BESSY beamline concept, which requires an additional mirror in front of the monochromator allows the collimation of the light with the presently planned number of optical elements.     

Historische Ziegeldeckenkonstruktionen

Historic brick floors. The renovation of buildings erected in the period from approximately 1890 until 1930 often reveals solid floor structures consisting of hollow bricks. With spans from about 1.40 m flat steel reinforcement is generally found between the brick courses. In the case of both the non‐reinforced and the reinforced brick floors the builders in this time had at their disposal a wide variety of different constructions. The following article outlines the historical development of these highly effective floor structural systems.     

Die ersten geschweißten Stahlbrücken in Deutschland – Über die wechselvollen Anfänge der Schweißtechnik

The first welded steel bridges in Germany – on the rocky beginnings of welding technology. Welding technology – and here primarily arc welding – began to be used about 80 years ago on bridges; first for repairing and strengthening them, and then increasingly, for building new ones. Initially, this new joining technology that had been used since before WWI in mechanical engineering, was met with skepticism on the part of building and code enforcement authorities, and hence, also by many in the building industry. Finally, in the early 1930's, welding technology started its explosive development in steel construction. This euphoric state was dampened a few years later due to several spectacular failures on bridges made of high‐quality construction steel. After comprehensive scientific studies were able to determine the causes of these failures, by the 1960's, welding finally established itself as the most important joining technology in steel bridge construction.