Operation of an experimental facility for fabrication of fuel elements and fuel assemblies of the bor-60 containing vibrocompacted fuel

Translated from Atomnaya Énergiya, Vol. 67, No. 5, pp. 320–323, November, 1989.     

A method of investigating the kinetics of high-temperature ductility variation of porous solids during sintering under pressure

Conclusions A method is proposed making it possible to study the high-temperature kinetics of the variation of the coefficients of shear ductility of a porous solid and its material during sintering under pressure. An investigation was carried out into the variation of the ductility of copper powder compacts in the temperature range 700–950°C. Experimental data are compared with results obtained on the basis of the theory of diffusion-viscous flow and a general rheological theory of sintering. It has been established that in the initial stage of sintering at 950°C the coefficient of shear ductility of copper increases linearly with time. Under conditions of diffusion-viscous flow of a polycrystalline material, this is due to diffusional grain growth according to a parabolic law. It is shown that experimental values of shear ductility of copper are smaller than values obtained on the basis of the rheological theory of sintering. Values approximating most closely to experimental data have been obtained with a model of an ideal porous solid.Translated from Poroshkovaya Metallurgiya, No. 11(299), pp. 11–17, November, 1987.     

A Compositional Framework for Hardware/Software Co-Design

We describe a compositional framework, together with its supporting toolset, for hardware/software co-design. Our framework is an integration of a formal approach within a traditional design flow. The formal approach is based on Interval Temporal Logic and its executable subset, Tempura. Refinement is the key element in our framework because it will derivefrom a single formal specification of the system the software and hardware parts of the implementation, while preserving all properties of the system specification. During refinement simulation is used to choose the appropriate refinement rules, which are applied automatically in the HOL system. The framework is illustrated with two case studies. The work presented is part of a UK collaborative research project between the Software Technology Research Laboratory at the De Montfort University and the Oxford University Computing Laboratory.     

Application of Physical Methods for Reducing Plutonium Hexafluoride

The exploding-wire method, the photochemical method of irradiation with a light flux from a high-pressure mercury lamp, a high-intensity spark discharge, and irradiation by a CO₂ laser are used to reduce plutonium hexafluoride and to separate it from uranium hexafluoride. The dependence of the reduction of plutonium hexafluoride on the wire material, the mass of the reduced product, and the amount of input energy is investigated.It is shown that the methods presented for reducing plutonium hexafluoride and separating it from uranium hexafluoride can be used under static and dynamic conditions for preparative purposes and on a large scale.     

Transmit/receive modules

This paper begins with a discussion of the microwave functions performed by transmit/receive (T/R) modules for phased-array antenna applications. The paper then addresses performance and cost aspects of semiconductor, packaging, and assembly technologies associated with T/R modules     

Features of Investigation into the Properties of Glasses and Melts from the Late 19th Century to the Present Day

The evolution of investigations into glass properties is described with the use of the SciGlass information system on the basis of an analysis of the world literature on glass from the end of the 19th century to the present day. Variations in the total amount of published data, in the interest of researchers in certain glass components and their properties, in the specific features of forming research groups, and in the general quality of publications are considered. Measures are proposed that can prevent a further decline in the quality of published experimental results.     

Effect of random distortions on the critical field in layered superconductors

Distortions of the layers in layered superconductors result in a decrease of the critical magnetic field. The distortions have the greatest influence when the field is applied at small angles to the layers. The critical field is calculated in the limits of large and small distortions. When the size of the distortion is less than the coherence length, superconductivity is destroyed by the usual second-order transition. In the opposite limiting case the possibility of superconducting current flow is determined by the percolation properties of the system. The dependence of the resistance on the value and on the angle of the magnetic field with respect to the layers is calculated in the percolation region.