Determination of cycle nonproportionality coefficient

We propose a cycle nonproportionality coefficient for a broad class of complex cyclic paths, allowing us to establish a clear relationship between the geometry of the strain path and the maximum hardening level attainable in the material in the steady state for a fixed value of the maximum plastic or total strain range. We discuss the effectiveness of using the proposed cycle nonproportionality coefficient compared with analogous parameters familiar from the literature. Based on a previously developed version of the endochronic theory of plasticity, we have numerically modeled the behavior of a material for cyclic loading along different planar nonproportional paths.Translated from Problemy Prochnosti, Nos. 5–6, pp. 29–38, May–June, 1995.     

Probabilistic reliable dissemination in large-scale systems

The growth of the Internet raises new challenges for the design of distributed systems and applications. In the context of group communication protocols, gossip-based schemes have attracted interest as they are scalable, easy to deploy, and resilient to network and process failures. However, traditional gossip-based protocols have two major drawbacks: 1) they rely on each peer having knowledge of the global membership; and 2) being oblivious to the network topology, they can impose a high load on network links when applied to wide-area settings. In this paper, we provide a theoretical analysis of gossip-based protocols which relates their reliability to key system parameters (the system size, failure rates, and number of gossip targets). The results provide guidelines for the design of practical protocols. In particular, they show how reliability can be maintained while alleviating drawback by: 1) providing each peer with only a small subset of the total membership information and drawback; and 2) organizing members into a hierarchical structure that reflects their proximity according to some network-related metric. We validate the analytical results by simulations and verify that the hierarchical gossip protocol considerably reduces the load on the network compared to the original, non-hierarchical protocol.     

A neural network compensator for uncertainties of roboticsmanipulators

A neural network controller for trajectory control of robotic manipulators that is used not to internalize the inverse dynamic model of the controlled object but to compensate only the uncertainties of the robotic manipulator is presented. Its performance is compared with that of the conventional adaptive scheme. The results show the ability of the neural network controller to adapt to unstructured effects. A learning method for the neural network compensator with true teaching signals is shown. The tracking error of the robotic manipulator was greatly reduced when this controller was used     

Metal fusion by laser radiation action in an oxidizing medium

Results are presented from a calculation of fusion of a massive zirconium plate under the action of laser radiation with consideration of simultaneous surface oxidation.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 61, No. 1, pp. 11–14, July, 1991.     

Morphology of thin anatase coatings prepared from alkoxide solutions containing organic polymer,affecting the photocatalytic decomposition of aqueous acetic acid

Porous anatase coatings were prepared from alkoxide solutions containing organic polymer by a dip-coating technique. The morphology of the coatings, such as pore size, pore distribution and thickness, was controlled. The effects of the morphology of the porous anatase coatings on the photocatalytic activity for the photocatalytic decomposition of aqueous acetic acid were examined.     

Experimental Investigation of the Density of Molten Lead–Bismuth Eutectic

The density of molten Pb–Bi eutectic is measured by the pycnometer method in a temperature range of 410–726 K. The confidence of error of measurement, made up by the systematic and random components, does not exceed 0.1%. The experimental results are compared with the experimental data on the density of a liquid lead–bismuth alloy of eutectic composition available in the literature.     

M. Yu. Bal'shin, A Founder in the Science of Powder Consolidation

The collection of analytical and experimental data makes it possible to consider the existence of three common scientific principles for solid body consolidation to be proved. One of them, the identity principle, formulates the degree of generality between properties and the behavior of a porous, consolidating or consolidated body, and a normal body; two others, i.e. the principle of self-regulation and the transmission principle, formulate features of the properties and behavior of powder bodies. The identity principle may be formulated as follows. The properties and behavior of any compact element of a porous body are the same as for the substance of a compact pore-free body with the condition of an identical chemical composition, degree of strain hardening, and test conditions. The self-regulation principle may be formulated as follows. During consolidation there are processes of non-self-regulation (intraparticle, consolidating, increasing and fixing the contacts and equilibrium) loading deformation and self-regulating (intraparticle, deconsolidating, reducing and breaking contacts and body equilibrium) unloading deformation; non-self-regulation consolidating deformation increases, and self-regulation deconsolidating deformation reduces compaction resistance; flow of particles substance is intermediate in nature between entirely continuous and entirely localized flow in contact areas. The greater the degree of consolidation, the lower is the level of self-regulation for its processes. The transmission principle may be formulated as follows. Consolidating stresses applied to a consolidating self-regulating body are transmitted by their elastic balancing in a continuous critical zone lying entirely within the solid phase of a body with equally large interparticle (contact) and intraparticle (critical) sections normal to the loading direction. These stresses and elastic loading are only transmitted through fixed, and not through broken, contact sections at this instant of consolidation, and consequently through fixed critical sections in a fixed critical zone.     

Of interest to the specialist — Innovations

All-Union Scientific Research Institute of the State Patent Examination (VNIIGPE). Translated from Metallurg, No. 6, pp. 29–31, June, 1991.     

Circular core polarization-maintaining optical fibers withelliptical stress-induced cladding

The reproducible technology for producing high-birefringence fibers with stress-induced elliptical cladding and circular core is described. The authors have obtained fibers that have a birefringence of about (1-3) 10^-4, a mode coupling parameter of about (2-7) 10 ^-5 m^-1, and loss of less than 0.5 dB/km at 1.6 μm. The authors have found effects restricting the capability of test fibers to maintain the state of linear polarization