Influence of production parameters on the superconducting properties of NbTi and Nb3Sn wires

The commercial specification of superconducting NbTi and Nb3 Sn composite wires is normally given by parameters such as the critical current (which is dependent on conductivity, temperature, and magnetic field), an empirically deduced parameter for which the effective resistivity is about 10-14 Ωm, wire and filament diameter, and twist length. To some extent their values cannot be chosen independently, nor do they guarantee proper operation of the system in all aspects. It is argued that for Nb3Sn composite, depending on the production process, an extra set of parameters describing the stress sensitivity seems to be needed to specify the quality of the composite

Anomalous skin effect in cylindrical samples

A description is given of the anomalous skin effect in a cylinder placed in an a.c. magnetic field parallel to the cylinder axis. The necessary nonlocal relation between current density and electric field inside the sample is established with the aid of Boltzmann's transport equation. Results are presented in terms of the current density in the sample and its magnetic susceptibility

The vector k-constrained KP hierarchy and Sato's Grassmannian

We use the representation theory of the infinite matrix group to show that (in the polynomial case) the $n$--vector $k$--constrained KP hierarchy has a natural geometrical interpretation on Sato's infinite Grassmannian. This description generalizes the the $k$--reduced KP or Gelfand--Dickey hierarchies.Comment: 15 pages, AMSTe

The response of metals in trapezoidal magnetic fields

The inductive response of metals to applied fields with trapezoidal time dependence is described for samples with cylindrical geometry and for slabs. The influence of coil effects and magnetoresistance is accounted for but mean free path and surface effects are ignored. Experimental data obtained for tin show a close agreement with the theoretical predictions

An analytic description of the vector constrained KP hierarchy

In this paper we give a geometric description in terms of the Grassmann manifold of Segal and Wilson, of the reduction of the KP hierarchy known as the vector $k$-constrained KP hierarchy. We also show in a geometric way that these hierarchies are equivalent to Krichever's general rational reductions of the KP hierarchy.Comment: 15 pages, Latex2

An environment for object-oriented real-time system design

A concise object-oriented method for the development of real-time systems has been composed. Hardware components are modelled by (software) base objects; base objects are controlled by a hierarchy of coordinator objects, expressed in an organizational diagram. The behaviour of objects is specified by state transition diagrams. This approach considerably promotes requirements analysis and communication with the customer. A CASE tool has been constructed with diagram editors for graphical specifications of real-time systems. The tool can generate executable code for PLCs from these graphical specifications; reuse of previous results is supported by the repository function of the tool. Experiences attained in practice with method and tool show that time spent in system testing and installation is reduced considerabl

GPU-driven recombination and transformation of YCoCg-R video samples

Common programmable Graphics Processing Units (GPU) are capable of more than just rendering real-time effects for games. They can also be used for image processing and the acceleration of video decoding. This paper describes an extended implementation of the H.264/AVC YCoCg-R to RGB color space transformation on the GPU. Both the color space transformation and recombination of the color samples from a nontrivial data layout are performed by the GPU. Using mid- to high-range GPUs, this extended implementation offers a significant gain in processing speed compared to an existing basic GPU version and an optimized CPU implementation. An ATI X1900 GPU was capable of processing more than 73 high-resolution 1080p YCoCg-R frames per second, which is over twice the speed of the CPU-only transformation using a Pentium D 820