Refractories for lining mobile mixers

Conclusions New and effective refractories have been developed whose physicotechnical and working parameters are better than those of existing Soviet and foreign materials. Commercial production of them has been organized.MKFU-83 and KKFU-76 refractories increase mixer lining resistance by substantial factors and reduce the number of repair cycles and the material and labor costs, while increasing the metal output. The refractories are recommended for use in steel-melting processes (electric furnaces and buckets).Translated from Ogneupory, No. 2, pp. 24–26, February, 1991.     

New Generation of Microfuel-Based Fuel Elements for VVÉR Reactors

The results of development work on a new generation of fuel elements based on microfuel for VVÉR reactors using the basic data from post-reactor investigations and bench tests in experiments simulating LOCA for existing fuel elements with ceramic fuel are presented. It is shown that cermet fuel elements will make it possible to realize most fully the advantages of such fuel, specifically, to develop a sealed first loop and to simplify and reduce the cost of safety, automatic control, radiation protection, coolant puification, and other systems. For example, cermet fuel elements in VVÉR-1500 reactors can improve safety under various operating conditions, maneuverability, vibrational strength, fuel assembly lifetime, and geometric stability of fuel elements.     

Discrete positions method in kinematics and control of spatial linkagesEine methode der diskreten lagen in der kinematik und steuerung der bewegungen raumlicher mechanismen

Using the screw theory in the field of infinitesimal displacements, the first and second order transfer functions of spatial kinematic chains are algebrised. Based on this, a method of finite increments of the relative displacements in the joints is offered. Finally, an algorithm for the control strategy of open kinematic chains of manipulators and robots was evolved using an imaginary closing of the kinematic chain while bearing in mind the conditions for instantaneous mobility (transitory).     

Ultrafine-grain structure and properties of carbon-steel wire after complex deformation

A continuous wire-deformation method is proposed. In this method, which has been patented in Russia, continuously moving wire is subjected simultaneously to tension in drawing, to flexure in a roller system, and to torsion. Metallographic data show that ultrafine-grain structure may be formed in carbon-steel wire. Mechanical tests confirm that the properties of carbon-steel wire may be improved by such deformational treatment.     

Study of the Practical Convergence of Evolutionary Algorithms for the Optimal Program Control of a Wheeled Robot

Evolutionary algorithms for solving the problem of the optimal program control are considered. The most popular evolutionary algorithms, the genetic algorithm (GA), the differential evolution (DE) algorithm, the particle swarm optimization (PSO), the bat-inspired algorithm (BIA), the bees algorithm (BA), and the grey wolf optimizer (GWO) algorithm are described. An experimental analysis of these algorithms and their comparison with gradient methods are given. An experiment was carried out to solve the problem of the optimal control of a mobile robot with phase constraints. Indicators of the best objective functional value, the average value for several startups, and the standard deviation were used to compare the algorithms.     

The development of technology for making SvAK12 welding wire from shaving billet

A technology for making a welding wire with a diameter of 1.2 and 2.0 mm from the shavings of SvAK12 aluminum alloy is developed. This technology includes hot briquetting the graded shaving scrap at 400–420°C, the hot extrusion of briquettes at 460–470°C with elongation factors of 32 and 56, cold wire drawing the extruded bars with average unit reductions for a pass of 15–20%, and intermediate annealings at 400°C. It is shown that this wire is suitable for soldering parts of aluminum alloys, and the level of the mechanical properties allows it to be recommended for wide application.     

Environmental aspects of thermal power equipment operation modes optimization

The article deals with development of methods for improving the efficiency of power generation in thermal power plants by means of main equipment operating mode optimization. The technique for efficient load distribution between cogeneration turbines for cogeneration of heat and electricity is introduced. The calculated fuel consumption corresponds to the optimal operating modes of turbines. The environmental aspects of optimization method have been considered. The economic effect from implementation of proposed technical solutions has been calculated. For more significant reduction of toxic compounds, generated in boiler furnace, the use of thermal effect from combustion of the hydrogen formed during the decomposition of the damp water, metered into the combustion chamber at temperature 1100 °C is introduced. The use of hydrogen additive as a source of additional stored energy due to combustion in the combustion device, expands the scope of its application in a power system significantly and provides normal emissions of toxic compounds into the air. The use of hydrogen additive in combustion refers to the best available techniques, implementation of which allows increasing the competitiveness of Russian energy production.     

The Geometry of the World of Currency Volatilities

Computational Economics - Using empirical data and the properties they reveal, we develop a factor that captures changes of both currency implied correlation and volatilities. For this purpose, we...     

An Experimental Technique for Aligning a Channel Optical Waveguide with an Optical Fiber Based on Reflections from the Far End of the Waveguide

Instruments and Experimental Techniques - A method for aligning the waveguide of a photonic integrated circuit and an optical fiber according to reflections from the far end of the waveguide, which...     

Microstructure and dielectric and piezoelectric properties of PbFe0.5Nb0.5O3 ceramics modified with Li2CO3 and MnO2

Unmodified lead ferroniobate (PFN) and samples modified with 1 wt % Li₂CO₃ (PFNL) and 1 wt % MnO₂ (PFNM) have been prepared by solid-state reactions followed by sintering by a conventional ceramic processing technique. The modifiers have been shown to change the nature of the recrystallization sintering process, reduce the optimal sintering temperature of the material, increase its average grain size, stabilize its dielectric properties, and improve its piezoelectric performance. The observed effects are interpreted in terms of the crystal-chemical specifics of the modifiers and their location in the structure of the parent compound.