The Evolution of Compact Binary Star Systems

We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs) within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA). Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure

Operation Modes of a 50-60 Hz Superconducting Converter

The operation at mains frequency of 50–60 Hz allows for a simplification of the superconducting converter construction at a reasonable efficiency of 96–98 % (while pumping up and down a superconducting magnet). Besides, new possibilities appear in the interaction between the mains and the magnet via the converter. The operation modes of a new superconducting converter connected to the mains and to the superconducting magnet are considered in the paper. The converter ‘cold’ part consists of the fast response thermally controlled switches, a non saturated iron core superconducting transformer and the current sensors in the branches. The PC-based control unit includes “direct” and “shunting” switches and allows to realise various algorithms of the converter control. It is shown that both AC to DC, and DC to AC conversion with the magnet-mains energy exchange in both directions via the converter can be realised. In the paper such an operation is described theoretically and verified by the physical and numerical experiments

Strategie používání PVC výrobků‚ následné odstranění

Použití metody LCA pro srovnání PVC výrobků a alternativních materiálů. Environmentální a zdravotní rizika způsobená výrobky z PVC. Systém sběru a fyzikální recyklace odpadu PVC podlahových krytin