On the existence of periodic motion and the maximum sector bounds for absolute stability of nonlinear nonstationary systems

In this contribution we consider the absolute stability problem. We derive necessary and sufficient conditions for the existence of periodic motion using an operator approach. The results yield an efficient algorithm to approximate the maximum sector bounds for absolute stability numerically.     

Construction and stratification of the stability domains of the linear dynamic systems with PID controllers

The regularities of motion of a point on the plane (in the space) of adjustable controller parameters at variations of the phase margin under a fixed crossover frequency were analyzed. The problem of decomposition of the stability domain into the zones with simple and complex Nyquist plots and subsequent construction of the point subset where all points satisfying the requirements on the system frequency characteristics was solved. Examples were presented.     

Contribution of the Research and Design Institute of Electrical Technology to the formulation of a strategy for the development of nuclear power in Russia

The results of investigations performed by specialists at Research and Design Institute of Electrical Technology together with other enterprises, institutes, and organizations concerning the formulation of a strategy for the development of nuclear power in Russia in the first half of the 21st century are presented. The individual stages of the work, key assumptions, ideas, and recommendations, on which the strategy is based, the initiatives which the President of the Russian Federation advanced at the millennium summit held at the United Nations, and the international INPRO project initiated by Russia are examined. It is concluded that innovative development and a transition to building as quickly as possible nuclear power objects that meet the requirements and demands of the new century are necessary. __________ Translated from Atomnaya énergiya,Vol. 103, No. 1, pp. 5–15, July, 2007.     

Development of methods of design,development, testing,and maintenance of real-time global space information-control systems

An approach to creation of real-time global space information-control systems referred to the class of complex systems based on methods of systems analysis, information technologies, and simulation, is considered. It is shown that objectives and tasks of any such system and requirements to it determine inevitable prior development of mathematical models of the system and of the environment realized on an imitation-simulation testbed, and a possibility of imitation testing with their help for more precise determination of characteristics of the system at all stages of its lifecycle. Particular examples of application of this approach are given.     

Design of the EPLD-based reconfigurable fault-tolerant systems with cell-level redundancy

A procedure to design reconfigurable systems capable to recover their operability in the case of fault of an arbitrary EPLD cell or connection was proposed. The most important advantages of the procedure lie in the retention of the signal propagation delays guaranteeing system operability after reconfiguration, as well as in low redundancy of the fault-tolerant system which at the limit may correspond only to one standby cell. The package methods enable one to design fault-tolerant systems based on the closed intelligent core without their upgrading. Efficiency of the procedure was estimated, and possible limitations of its application were discussed.     

Optimization techniques for curved path computing

Participating media with an inhomogeneous index of refraction make light follow curved paths. Simulating this in a global illumination environment has usually been neglected due to the complexity of the calculations involved, sacrificing accurate physical simulations for efficient visual results. This paper aims to simulate non-linear media in a more reasonable time than previous works without losing physical correctness. Accuracy is achieved by solving the Eikonal equation of geometrical optics, which describes the path followed by a light beam that traverses a non-linear medium. This equation is used in the context of a photon mapping extension.     

Effect of prolonged high-temperature loading on the structure of the KhN65VMTYu alloy

A complex analysis of changes in the structure and in the phase composition arising as a result of both a prolonged operation of articles made of the alloy KhN65VMTYu (EI893) and after conducting imitation tests of model samples. The tests for long-term strength using samples cut out from the body of a large-dimension turbine blade which was exploited for 63 622 h showed that the blade preserved a significant residual reserve of service life (at 750°C and 250 MPa, the time to failure is 4243.5 h).     

Antiwear Action of Mineral Lubricants Modified by Conventional and Uncoventional Additives

The authors of this paper investigated the influence of esters of rapeseed oil fatty acids on the lubricating properties of mineral lubricants containing chosen AW/EP additives. Methyl esters, ethylene glycol esters, and glycerol esters as well as some commercial AW/EP packages based on zinc dialkyldithiophosphate, S–P organic compounds, and sulphurized esters of fatty acids were tested. The tribological tests were carried out with the use of a four-ball machine. Antiwear (AW) properties of tested compositions were determined using their limiting load of wear (G_oz(40)). It appears that the AW action of esters of rapeseed oil fatty acids depends on their structure. The best AW action is shown by compositions of mineral oil lubricants containing AW/EP additives and methyl esters of rapeseed oil fatty acids. The SEM/EDS analysis of the scar surface layer indicated that the presence of these esters in lubricants causes a change in the interaction between AW/EP additives and the metal surface. These observations were confirmed by the XPS surface analysis.