Evaluation of condition of low-carbon steels experiencing plastic deformation using the effect of acoustic birefringence
The influence of plastic deformation of low-carbon steel on birefringence of the shear waves birefringence is examined. Acoustic measurements show that the birefringence changes monotonously, while the intensity of the change decreases with increasing strain. Significant reduction of the birefringence is found to indicate that the capability to plastic deformation has been largely used. In order to explain the experimental results, computer simulations of the crystallographic texture of a polycrystalline material, and its change during plastic deformation, have been carried out. It has been found that internal stresses due to the presence of mesodefects, accumulating at grain boundaries, have a significant effect on the crystallographic texture and the birefringence. Thus, this effect allows one condition monitoring of a plastically deformed low-carbon steels under plastic deformation.
The paper deals with an investigation of relief formation in Europa's surface. Jupiter's satellite Europa is close in size to the Moon. Its surface is covered with a layer of ice crust of thickness 10-30 km. Europa's surface is of large interest, because under the ice crust there is an ocean of liquid water creating conditions for possible life. The entire ice surface of the satellite is covered with a system of bands, valleys, and ridges. These structures are explained by the fact, that the ice surface is rather mobile and it was repeatedly broken from internal stresses and large-scale tectonic processes. The analysis performed showed that compressing, extending, shearing and bending stresses can influence some arbitrarily separated section of Europe's ice surface. The computer simulation with a finite element method (FEM) was performed to see, what types of defects could arise from such effects. The heterogeneity of the satellite's ice cover in thickness, density and temperature was taking into account during the simulation. The calculations, carried out for the cross-section of a thawed ice structure's area, have shown that, the most dangerous, from the crack formation viewpoint, is the shear stress at loading application angles of ±90°. Using models of thawed ice patches in the distributed field of temperatures, the effect of mechanical gravitation-tidal forces on the formation of surface defects on Europa was studied. It is shown that fractures and cracks can have various forms depending on the stress-strained state arising in their vicinity. The formation of such defects is caused by the chaotic set of many factors, mechanic and temperature ones predominantly. Copyright © 2013 by the International Astronautical Federation. All rights reserved.
The following topics were dealt with: human/computer interfaces; texture, depth and motor perception; neural nets; fuzzy systems; learning; product/process design; simulation; robotics; visual system cybernetics; batch processes; image compression and interpretation; AI applications; fuzzy adaptive control; decision modelling; agile manufacturing; service sector; inductive algorithms; complex systems; Petri nets; real time imaging; KBS; machine recognition; requirements engineering; inspection and shop floor control; environmental decision making; medicine; supervisory control; discrete event systems; power systems; software methods; heuristic search; vision systems; database systems; information modelling; facility design and material handling; conflict resolution; emergency management; genetic algorithms; decision making and path planning; IVHS; senses approximation; intelligent user interface; robust controllers for mechanical systems; cognitive and learning systems; command and control systems; pilot associate systems; neural net applications; real time systems; mobile robot visual processes; medical applications; utility energy systems; machine recognition; computing systems design; software engineering; military applications; data analysis; stochastic processes; guided vehicles; and stability and compensation.
Computer simulation of equilibrium prices for the stock exchange
The results concern roll pass design for rolling a round bar of a 20mm diameter from a 55mm diameter input. Concerning materials, this roll pass design must cover a wide range of steels, from low-carbon micro-alloyed steels to stainless steels. The roll pass design proposal takes into consideration lower plasticity of certain steels. The comparison was enabled by suggesting two roll pass designs. The classical oval-round roll pass design, where the maximum extension coefficient is set to 1.55 in oval and 1.22 in round grooves. The second roll pass design uses a combination of smooth part of the roll (curves) and round roll passes. Distribution of the extension coefficient in individual passes is similar to that of oval-round series. The paper also compares values of energy-force parameters calculated analytically using the method of finite elements. If we compare the distribution of temperature, stress and size of the grain, it is proved that the oval-round roll pass designs are the best as far as the balanced distribution of the above-mentioned values is concerned. The roll pas design combining smooth part of the roll with a round part does not achieve such balance. However, its advantage lies in far lower requirement for the needed length of the working part of the roll. Five passes are carried out on the smooth part of the roll, which considerably cuts down the required length of the roll body. Therefore it is this variant that will be used in the laboratory of wire rolling created within the project RMSTC.
Mathematical and computer simulation of economic processes.
In the article are esteemed assigning and main capabilities of the subsystem of the analysis and maintenance of thermal values of designs of radio electronic means ASONIKA-T, and also principles of simulation of thermal processes in designs with the help of the subsystem ASONIKA-T. The example of simulation of thermal processes in a standard design is adduced.
In this paper the model of mechanical interaction of rough surfaces is constructed as Markov's process with continuous time is under construction. The basis is the discrete model which is taking into account elastic and plastic deformations and fatigue failure at action of constant loading. The system of Kolmogorov-Feller's integral-differential equations concerning distributions of heights of ledges changing in time is written out. The settlement example of evolution of distributions is resulted.
The application of mathematical modeling methods (with subsequent computer sales) to determine the parameters of accuracy geometry bands obtained with the new equipment and process the step deformation bands of hard alloys based on copper
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.