Invariant critical sets of conserved quantities

For a dynamical system we will construct various invariant sets starting from its conserved quantities. We will give conditions under which certain solutions of a nonlinear system are also solutions for a simpler dynamical system, for example when they are solutions for a linear dynamical system. We will apply these results to the example of Toda lattice

Study of Tribological Properties of Nanolamellar WS 2

This work was aimed at studying the tribological properties of nanolamellar tungsten and molybdenum disulfides produced from nanosized W and Mo nanopowders by self-propagating high-temperature synthesis. The prepared WS2 and MoS2 powders were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential thermal analysis (DTA). For tribological tests, oil-based lubricants added with nanolamellar tungsten and molybdenum disulfides were prepared. The tribological tests show that the friction coefficient of the nanolamellar powders is lower than that of commercial powder (μmin=0.024 and 0.064, resp.). It is also found that the oil-based lubricants with nanolamellar disulfide additives display higher antifriction and antiwear properties compared to commercial powder

On One Approach to Investigation of Mechanical System

The paper presents some results of qualitative analysis of Kirchhoff's differential equations describing motion of a rigid body in ideal fluid in Sokolov's case. The research methods are based on Lyapunov's classical results. Methods of computer algebra implemented in the computer algebra system (CAS) "Mathematica" were also used. Combination of these methods allowed us to obtain rather detailed information on qualitative properties for some classes of solutions of the equations

Operating System Fundamentals

xi, 498 hlm.; Ind.; 24 c

Invariant varieties of stationary movements and their stability

A system of the mine power supply is considered in the paper aiming at the collection establishment of main dependences and laws of the control object displacement. The development of models, structures, algorithms of the functioning, methods and means for the effective control of mine power supply systems is also the aim of the paper. As a result the hierarchical structure model of the control distribution system, making it possible to estimate the degree of the information packing (aggregation) has been developed as well as the method of the control system analysis, consisting of the division of the controlled object set on separate subsets. The automatic-decomposition model, functioning algorithms, structures and new principles of the technical realization of the multilevel system for the mine power supply automated control have been created as well as the universal devices on microprocessor controllers, realizing the functions of the distributed system logical control. Scientific statements, conclusions and recommendations have been realized in the form of normative-technical and methodical documents, introduced on coal mines of main basins. There in the economic effectAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Tribological Properties of Nanolamellar MoS2 Doped with Copper Nanoparticles

This study aimed at examining the tribological properties of nanolamellar molybdenum disulfide doped with copper nanoparticles. Nanolamellar molybdenum disulfide was produced using self-propagating high-temperature synthesis via the reaction between elementary sulfur and nanosized molybdenum powder prepared by electrical explosion of wires. Copper nanoparticles were also prepared by electrical explosion of copper wires. Comparative tribological tests were carried out for nanolamellar and commercial molybdenum disulfides doped with 7 wt.% of copper nanoparticles. It was demonstrated that doping copper nanoparticles additives reduce wear of the friction body when using both commercial and nanolamellar molybdenum disulfide

A Parallel Symbolic-Numerical Approach to Algebraic Curve Plotting

We describe a parallel hybrid symbolic-numerical solution to the problem of reliably plotting a plane algebraic curve. The original sequential program is implemented in the software library CASA on the basis of the computer algebra system Maple. The new parallel version is based on Distributed Maple, a distributed programming extension written in Java. We describe the mathematical foundations of the algorithm, give sequential algorithmic improvements and discuss our parallelization approach