Express Method for Estimation of Tensile Strength and Crack Resistance of Brittle Media

The procedure is proposed for estimating the crack resistance and tensile strength of rocks by the results of experiments on disk samples with holes. The gradient approach to the strength problem is employed in processing the experimental data.     

Dynamical adaptive synchronization

The notions of dynamical synchronization and adaptive dynamical synchronization problems are introduced. The algorithm solving adaptive synchronization problem for a subclass of Lurie systems with exciting input is proposed. The performance and potentialities of proposed solutions are demonstrated by two examples related to formation control and self‐organization of swarm systems. Copyright © 2006 John Wiley & Sons, Ltd.     

Some characteristics of the combustion of metals in an N2+O2 flow

An experimental study was made of the effect of the velocity of an N₂+O₂ flow and its oxygen content on the rate and nature of combustion of specimens of titanium alloys and St. 20. The limit flow velocities for which combustion is still self-sustaining were obtained as a function of the O₂ concentration.N. E. Zhukovskii Central Aero-Hydrodynamics Institute, 140160 Zhukovski. Translated from Fizika Goreniya i Vzryva, Vol. 30, No. 6, pp. 68–71, November–December, 1994.     

Linear signal distortion compensation using harmonic decomposition

Compensating for linear distortions of a signal under uniform sampling using Fourier series is considered.     

Initiation of combustion of titanium plates in an air stream by pulsed radiation

We have experimentally investigated the effect of the velocity of an air stream and the static pressure in the stream in the subsonic, near sonic, and supersonic flow regimes on the process of initiation of self-sustaining combustion of plates made from titanium alloy OT4-1V by pulsed laser radiation. We have established the existence of an upper limit for the flow velocity for initiation of combustion. We have shown that reduction of the static pressure below atmospheric leads to a sharp reduction of the range of flow velocities for which self sustaining combustion of the plates is initiated; and for p<0.6·10⁵ Pa, combustion does not develop over the entire range of M numbers from 0 to 2.5.Central Institute of Aerodynamics, 3 Zhukovskii 140160. Translated from Fizika Goreniya i Vzryva, Vol. 30, No. 2, pp. 46–51, March–April, 1994.     

Design of interval observers for uncertain dynamical systems

Interval state observers provide an estimate on the set of admissible values of the state vector at each instant of time. Ideally, the size of the evaluated set is proportional to the model uncertainty, thus interval observers generate the state estimates with estimation error bounds, similarly to Kalman filters, but in the deterministic framework. Main tools and techniques for design of interval observers are reviewed in this tutorial for continuous-time, discrete-time and time-delayed systems.     

Control problems in contingency during flight of a space vehicle with low thrust engine

An approximate method of online analysis of contingency during the flight of a space vehicle with low thrust engine and nuclear power unit to asteroids is proposed. The properties of dependence of the vehicle mass near the target on the flight characteristics and parameters of the space vehicle are used. Examples of the choice of a new variant of the expedition to several asteroids of the Main belt in the case of a contingent change in the power of the energy unit are given.     

Increasing the Resistance of Automobile Sheet to Atmospheric Corrosion by Optimizing its Chemical Composition and the Parameters of the Manufacturing Process

A method involving alternating immersion in a 3.5% NaCl solution has been developed for corrosion tests of automobile sheet. Results obtained from 30 cycles of tests (10 + 50 min) of specimens of steels 08Yu, 08ps, 08YuP, 08YuDP, 08GSYuT, and IF established the dependence of the steel's unit weight gain from corrosion products on its combined content of carbon and silicon: steels with a lower content of these elements show a smaller gain in weight, i.e., they exhibit greater corrosion resistance. Steel alloyed with copper (0.23–0.34%) and phosphorus (0.06–0.08%) – the production of which has been mastered by the company Severstal' — has the highest resistance to corrosion. Use of the method makes it possible to rank grades of automobile sheet in one of three corrosion-resistance classifications in relation to their chemical composition and the parameters of the production process. __________ Translated from Metallurg, No. 8, pp. 46–52, August, 2005.     

Analysis of the Polonium Hazard in Nuclear Power Systems with Lead–Bismuth Coolant

Polonium presents no danger under normal operating conditions when the coolant loop is sealed. In our country, we have almost 40 years of experience in working with radioactive lead–bismuth coolant in the reactors used in nuclear-powered submarines and ground-based testing prototypes. This experience has made it possible to study how the polonium radiation conditions inside working enclosures are produced and to develop effective safety measures for different operating regimes, including irregular situations and accidents.Data are presented on the polonium radiation conditions in certain typical operating and accident situations in a nuclear submarine: spillage of a substantial amount of coolant directly into the reactor bay, the consequences of an interloop leak in a steam generator, and refueling with fresh nuclear fuel.Regular medical-biological examinations of the workers participating in the operation of the system, repair work, and liquidation of the consequences of accidents did not show any cases of irradiation by polonium above the established health norms.Inferences are drawn from studies performed in this and other countries of polonium emission from lead-based polonium-containing media when such media are heated in vacuum and in an inert-gas atmosphere in the temperature range 300–800°C.