No 3-1 (2015)

The article meets the challenge of the synchronization detection in the code sequence of uneven codes, lost in the result of impact of errors in the communication channel when transmitting compressed messages.

For this purpose, basing on statistical properties of the messages and digital communication channel source, the authors got the observation likelihood functions in the presence and in the absence of synchronization. In this situation, the frequencies of occurrence of volume-defined alphabetic letters in the decoded sequence of characters can be used as the observations. As a primary distribution, the authors used a polynomial distribution, which characterizes the frequencies of occurrence of alphabetic letters in the volume-defined selection depending on their probabilities. The peculiarity of this approach for the synchronization detection is the use of polynomial distribution for description of the function of synchronization unavailability likelihood on the basis of the theory of complex hypotheses recognition with a uniform averaging.

In the result of such approach, the authors obtained the likelihood ratio depending on the probabilities of alphabetic letters occurrence using which it is possible to make the conclusion about the presence or absence of synchronization.

The algorithm for synchronization detection in event of non-uniform encoding was developed on the base of the sequential analysis procedure. The value of average Bayes risk presented in the form of probability of synchronization detection error was selected to be an indicator for the algorithm effectiveness evaluation.

The analysis of noise stability of uneven codes shows that the application of modern multimedia technologies in communication networks increases the amount of transmitted information and used alphabet of messages that leads to the loss of synchronization and the effect of error propagation. It causes partial or total loss of data. The developed algorithm will allow recovering of the compressed messages that were distorted during their transmission via communication channel.

The author presents the technique of calculated evaluation of processing errors arising from thermal deformations during the blank part and cutting tool processing. The assigned task was solved using the dimensionless groups of cutting process which consider process conditions, such as: cutting mode (cutting speed, feed motion and cutting depth), tool cutting part geometry (face and clearance angles, plan root radius, cutting edge rounding-off radius), mechanical and physical and thermophysical properties of processed and tool materials (flow shear resistance of processed material, heat conduction of processed and tool materials, temperature linear expansion factors of processed and tool materials).

Theoretical dependences allowed getting the numerical values of errors arising from thermal deformations of a blank part and the cutting tool. It allowed evaluating the efficiency of feed, cutting speed and other cutting process parameters.

When evaluating errors arising from thermal deformation of cutting tool, the author considered heat transfer to the external environment through the cutting tool side face.

When getting theoretical dependences for evaluation of processing errors, the author used the dependences for evaluation of temperature in the cutting area and its expansion within the blank part and cutting tool got by the Professors S.S. Silin, A.N. Reznikov, A.V. Lykov and others.

The comparison of values of processing errors arising from thermal deformation of processed blank part and cutting tool showed their close agreement that is quite acceptable for practical purposes.

The study showed that the applying of solid lubricants (SL) in the form of solid lubricant sticks (SLS) is one of the effective means for quality improvement of the surface layer of machine parts used during the grinding operations performed without lubricating-cooling fluids (grinding of parts of electro-technical devices, sharpening of edge cutting tools and so on). The authors defined that the roughness of the parts surfaces during the grinding using SLs can be reduced by introduction of finely dispersed natural and nanomaterial fillers to their compound. The study showed that to predict the parts roughness parameters during the grinding operations using SLs it is very important to have a calculation procedure for these parameters which takes into account the influence of the processing mode, processed blank part material, grinding wheel (GW) characteristics, SL compound and consumption. The authors presented the procedure for calculation of height roughness parameters of parts ground using SLs with the fillers of nanomaterials and finely dispersed natural materials during the operation of surface grinding with the periphery of a straight wheel. To prove the adequacy of the procedure, the authors give the results of experimental study which were carried out on the 3E711VF2 surface-grinding machine varying the SL compound and consumption, time and grinding modes, and the abrasive tool characteristics. During the study, the authors monitored the static and dynamic vibrations amplitude, and the roughness of the ground surfaces, which was assessed according to three height parameters (as per GOST standard 25142): arithmetic average roughness height Ra, ten-point height of irregularities Rz, and maximum height of profile Rmax. According to the results of comparing calculated (Ra_c) and experimental (Ra_e) values of arithmetic average roughness height Ra of the ground surfaces the authors concluded sufficiently high accuracy of calculation. The discrepancy between the calculated and experimental values ​​did not exceed 10 ... 18%.

One of the main issues of modern manufacturing engineering is the development of actions and creation of equipment for machine durability improvement within the speed range and hard loading operational modes. For today, the task of provision of the parts bulk strength under the ordinary working conditions is considered to be nearly resolved. That is why the surface layer state, its wear resistance and lubricating conditions are of great importance now. The task of improvement of oil-retaining property of sliding surfaces is essential for machines of various purposes.   

The paper presents the results of analysis of existing equipment for oil-retaining profiles applying and determines its weak points. The authors offered new design of vibration equipment referred to the technology of applying of oil-retaining holes on the sliding surfaces in order to decrease the friction forces and the wear of inner surface of friction bearing bush, and can be used in various branches of machine-building complex. The authors developed experimental equipment, measuring equipment and the research technique. To carry out comparative study the samples of friction couples were created. The authors carried out the study of working capacity of friction units without holes and with holes on the stub shafts using the method of assessment of size of inner bush surface wear scar. Proposed design of vibration equipment for applying of oil-retaining holes on the stub shafts allows increasing flow rate and, consequently, the metal balls impact force due to the use of inverted valve. The increase of vibration frequency will make it possible to increase the efficiency of the process of oil-retaining profile applying. The study proved the working capacity of suggested equipment and showed the decrease of friction couple wear.

Pipes with silicate enamel coating are widely used in heat-and-power engineering, chemical and petrochemical manufacturing engineering, oil production and transportation. Pipes with internal silicate enamel coating are recommended by documentary standard for construction of fire-fighting systems for tanks for oil and oil products.

Serviceability of pipelines is determined by corrosion resistance of inside surface of welded joint. While welding pipelines with silicate enamel coating, as a result of high-temperature action, the enamel burning and vaporization, pore formation, bubbling, and macro- and micro crack formation take place in the heat-affected area. 

To reduce thermal action on the silicate enamel coating the authors offered to substitute steel weld base with the non-ferrous metal alloys having lower melting point. Zinc, copper and copper-based alloys, nickel and nickel-based alloys were selected to be such metals with allowance for melting point.

Tests of welding joints mechanical properties showed the applicability of copper and nickel alloys as the electrode material for machine welding of pipes with internal silicate enamel coating. When applying these materials the mechanical properties of welding joints have the same level as the properties ensured by welding with Sv-08G2S steel electrode wire.

Surface and chemical analysis of silicate enamel coating proved the effective application of CuSi3 electrode wire. Machine welding using CuSi3 electrode wire provided minimum damage and changes in chemical composition of silicate enamel coating.

The authors suggested a common approach and work technique for temperature determination while grinding by plain, interrupted and highly porous grinding wheels on the basis of presentation of thermal process during grinding as a single heating and cooling cycle (plain wheels) or as a complex of such cycles (interrupted and highly porous wheels). According to this presentation, the authors suggested distinguishing macro- and micro-interrupted grinding, respectively, for grinding by interrupted (macro-interrupted) and highly porous (micro-interrupted) grinding wheels. In this case, the principle of superposition of thermal fields caused by positive and negative heat source successive exposure on the processed surface at macro- and micro-levels is used according to the frequency of this exposure. The study showed that the increase of number of cutting ledges on the interrupted wheel at a constant duty cycle for these ledges circular pitch (the inverse value for pulse relative duration of heat flow) causes the reduction of grinding temperature under otherwise equal conditions. Equal grinding rate of wheels of compared designs is one of these conditions.  The same trend for grinding temperature reduction takes place when increasing the duty cycle for circular pitch at a constant number of cutting ledges. The authors determined that the increase in quantity of cutting ledges on the wheel periphery causes the decrease of duty cycle influence on the temperature. The regularity of interrupted grinding temperature decrease during the increase of cutting ledges number and duty cycle (under otherwise equal conditions) confirms the validity of the discernible trend for replacing the plain interrupted wheels (macro-interrupted) with the highly porous grinding wheels (micro-interrupted) appropriate by overall dimensions. The authors present the technique for grinding temperature determination while grinding by the highly porous wheels which can be used when designing the optimal composition for these wheels and selecting their components.

This paper presents the detailed analytical method of calculation of temperature fields for the blade tool cutting process. The author considers in details the heat sources forms during cutting, the possibility and necessity of schematization both of the heat sources and the forms of interacting bodies. The calculation of temperature in the zone of primary plastic deformation is carried out taking into account the mutual influence of temperature on the intensity of shear stresses within this area. The author determined that the distribution of intensity of friction source along the back surface is stipulated by the nature of changes in friction induced shear stresses and is little different from the uniform one. The author offered the accurate solution of the issue of calculating temperature within the half-space from the action of a rectangular constant rate heat source. Thus, it became possible to determine the rate of constant heat flows on the front and back surfaces. The author tested a hypothesis about the constancy of heat flows rate. For this purpose, each final heat source was presented as a combination of elementary uniform heat sources. The research proved the large non-uniformity of rate distribution of heat sources that act on the cutting tool surfaces. This made it possible to identify new patterns of temperature distribution on the front and back surfaces of tool within various combinations of heat conductivity of the processed and tool materials, as well as the tool wear. The author identified the essential influence of body deferred on the front surface on the amount and direction of heat flows within the front and back surfaces – to the tool or to the blank part, and eventually on the temperature of cutting tool contact surfaces. It allowed development of guidelines for selecting optimal tool material for processing of blank parts with different heat conductivity.

The paper considers the state of networks and facilities and the ways of efficiency improvement of utility and drinking water supply systems operation in the Volga region environment using the example of Togliatti city district. The author defines the priorities according to the strategy of social and economic development of Samara region for the period until the year 2020. It is noted, that the main life spheres ensuring the safety of human life and health and, consequently, the increase of the amount of housing construction and the communal infrastructure, as well as the reduction of existing housing funds and communal infrastructure to the compliance with the quality standards are considered to be the priorities of state policy in the region.  The supply of population with pure water is the priority problem which decision is necessary for health keeping and the human life level improvement. This paper gives the ecologo-statistical analysis of water supply sources, hydraulic and technological analysis of the processes of preparing and transporting drinkable water, the state of pipelines of water distribution and the degree of their breakdowns in order to make a decision on the ensuring of hydraulic decision, efficiency improvement of utility and drinking water supply and distribution while operating water supply systems of Russia using the example of Togliatti city district. The improvement of level of anthropogenic pollution of drinking water supply sources, the significant wear of buildings and equipment of water sector, the lack of reserve water source (Avtozavodskiy district) determine the topicality of the problem of guaranteed supply of population with pure drinking water and make it the priority task of social and economic development of Togliatti city district. It is noted, that in order to solve the problem of supply of population of Togliatti city district with pure drinking water it is necessary to organize united actions of executive and legislative authorities, water sector enterprises, investors, technical specialists, population on the creation in water sector of effective whole new modern forms and methods of management. The author recommends alternative variants of reconstruction and operation of networks and buildings of utility and drinking water supply systems in this region. The scale of the problem causes the necessity to develop the Program with the use of target-oriented solution for the complex of organizational and technical, juridical, economic, social and other objectives and actions ensuring the conditions for the Program implementation. The application of special-purpose approach should provide the effective solution of system problems within the city water sector at the account of implementation of the complex of program actions fit together by the objectives, resources and deadlines.   

Abrasive grinding takes the important place among various methods of mechanical treatment which provide meeting the requirements to the surface layer quality, shape and dimensions accuracy of the treated surface; and the use of vibration grinding method is considered to be the most advanced. 

The authors offered the design of resonant vibration machine with magnetic actuator of circular translational vibrations of laps in flatness. Basing on the fact that the vibration isolators’ hardness is rather weak and they are located in the system close to the point which vibrations are equal to zero, the authors made a supposition that it is possible not to take into account their dynamic pressure on immovable base. For the suggested design of equipment, the authors set up the equations of motion in joint coordinates and, applying the method of Lagrange, recorded the expression for kinetic energy of the system which consists of the energy of translational motion of system masses and the energy of rotational motion around the mass centers. The analysis of the suggested analytical model showed that it can be worked out to a single-mass system with a single degree-of-freedom. It will allow considerable simplification of determination of analytical estimated dependences for calculation of major structure parameters and working modes of machine drive and will reduce further experimental studies during the adjusting and setting of grinding process on such machines. The authors developed and implemented a vibration grinding machine with magnetic vibration actuator where the grinding of flat and cylindrical parts is carried out during their positioning to the slots of separator buckle plates creating complex ordered motion of treated parts against the working surfaces of grinding tools.    

The article considers the crucial task of determining a strategy for effective and ecologically friendly utilization of automobile accumulator batteries (AAB) being one of the most dangerous for the environment recoverable vehicle components. For this purpose, basing on the descriptions of invention patents, the authors carried out the general information analysis of known innovative AAB utilization technologies and considered the technological procedures of AAB recycling utilization represented in descriptions of national patents for inventions of methods and technical devices used for their implementation. Moreover, a patent search was performed and the numbers of patents and patent applications for inventions on this topic of leading Western countries were identified. They include both the methods and technical devices for AAB utilization separation into individual constituent components – plumbiferous (zinc-containing), electrolyte solutions, polymeric housing elements, and the direct utilization recycled processing of each noted AAB constituent element. There is a great variety of well-known technological procedures for utilization processing of plumbiferous battery scrap that are based on the implementation of various thermochemical transformations in order to get raw materials suitable for reuse. The procedures of utilization processing of AAB electrolyte solutions and polymeric housing elements are represented least of all. Obviously, it is caused by the demand and economic interest in obtaining a much more valuable commodity product from plumbiferous (zinc-containing) scrap. At the same time, the more stringent environmental legislation forces AAB developers and manufacturers to create more efficient technological procedures of utilization processing of all AAB components. The authors highlighted the feasibly prospective way of development of ecologically friendly disposal of polymeric solid waste, which is based on materials recycling resulting into production of corresponding semi finished polymeric crushed fragments which can be used as the effective sound-absorbing substances within different types of noise reducing device constructions.

There are various methods of piercing. The authors suggest using the process of metal piercing with the help of electric discharge between the electrolyte jet and the solid electrode, or the processed part. The electric discharge between the electrolytic electrode and the processed part can be used both for piercing and for deburring, surface cleaning, metal cutting, and parts marking. To investigate the current-voltage characteristic, the dependence of discharge current on volume electrolyte velocity, and the dependence of current density between the electrolyte jet, the authors developed the portable hand-held tool of “gun” type. The study showed that the discharge between the electrolyte jet and the processed part strikes and burns at U=510–515 V. When the discharge changes to the electrolysis mode, the current increases in 1.5–2 times. With the increase of volume electrolyte velocity the discharge current grows. The study of the dependence of discharge current density between the electrolyte jet and metal anode on the discharge current showed that with the increase of current the density of current on the electrolytic electrode grows in a linear function. The analysis and synthesis of a large number of experimental data proved that the electrical discharge can be used for engineering purposes. Using the plasma of discharge with electrolyte jet it is possible to perform such operations as the tubes inner surfaces cleaning, metal piercing, metal cutting, deburring of parts edges, and product marking without changing the properties of the rest mass of a part.