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  • Research of influence of concentrators on the stress-strain state in flat specimens of pipes under pressure

    The technique of the research problem solution of influence of different types of concentrators on the stress-strain state of main gasline pipes involving compact flat specimen is considered. The algorithm of carrying out numerical experiment and its realization in the APDL language in the ANSYS is developed, one of possible forms of additional stress concentration – a circle is considered, and shown its influence on stress redistribution, the size and a form of area of a biaxial stress.

    Keywords: stress-strain state, flat specimen, stress concentration, finite element method, automation of finite elements grid creation, defects in pipes, weld

  • Repair of vehicles and special equipment in the field

    Abstract: Operation of motor transport and special equipment is carried out in difficult conditions, the impact of environmental conditions (temperature, humidity, dust, wind, solar radiation) and changes in modes of operation of the machine. This affects the performance of equipment, the number and complexity of repairs. Away from fixed bases (in the field), the problem is particularly acute repairs. One of the most energy-intensive and expensive works are welding (welding parts with a break, welding cracks, fusing metal layer on the worn surface, metal cutting). In this work the welding equipment affect the voltage drops in the supply mains, therefore, produces a large number of failures such equipment. After the equipment is accompanied by an increased amount of electric power consumption, this results in material costs. Previously proposed equipment has improved mass, which reduces the efficiency of the welding. Based on this study was proposed innovative design welding inverter using the resonance effect, with enhanced reliability, low-cost design version (in terms of mass production). In order to improve the reliability and reduce the cost of the proposed design of inverter proposed a number of new approaches. Full-bridge inverter is studied welding power source with the implementation of the resonance effect with a stable and smooth operation, high reliability, because the circuit of the inverter is not sensitive to changes in the supply voltage.

    Keywords: repair, motor trucks, welding, full-bridge inverter welding power source, the resonance effect.

  • Detoxication of pesticide and other toxic substance remains in soil with the help of nanomaterials

    Intensification of agricultural production involves a large – scale use of fertilizers, plant protection means against pests, diseases and weeds, all those are used within various modern agro-technologies, which leads to soil intoxication with residual amounts of pesticides and agrochemicals. Therefore, a comprehensive approach is necessary for preparing the soil for further sowing. We have carried out the research using activated carbons obtained from agricultural residues.

    Keywords: detoxication, pesticide, toxic substance,active carbon, nanomaterials, (nano)chips, pre-sowing seed treatment;growth, development, the incidence of plants, the quantity and quality of their crop

  • The analysis of the analog characteristics of circuits ADS1293 for application in medical technology

    In this article the testing of analog characteristics of AFE-circuits ADS1293A on measuring stand are presented. The analysis of the characteristics of the chip to be used in medical equipment.

    Keywords: AFE-chip, Holter monitor, cardiograph, testing energy, medical equipment

  • Study the possibility of using the accelerometer to control the medical device with battery

    In this article the question of the possibility of using the accelerometer to control the medical device. The analysis of existing models for this purpose. Then made ​​all the necessary tests at the research booth

    Keywords: accelerometer, taping, tap-tap, LIS2DM, ADXL345, MMA8450Q, medical equipment, self-powered

  • Theoretical and experimental study of scattering characteristics of the microstrip array with nonstationary non-linear loads

    By means of Lemma Lorentz solution to the problem of excitation of an infinite periodic microstrip array with non-linear loads (NN), whose parameters vary in time, was obtained. For the formation of a system of integral equations nonlinear boundary conditions of impedance type, arising from polynomial representation of V-I characteristics of non-linear loads was applied. Numerically patterns in dependence of the reflectance of such a array at combination frequencies on the electrical parameters of loads were identified. The experimental data which confirm possibility of control with levels of combinative frequency components by frequency change and amplitude of voltage pump are given.

    Keywords: microstrip structure, non-linear loads, spectrum of the reflected signal, combinational harmonics, parametric excitation

  • Electronic structure and magnetic properties of quasi-2D systems MeO (Me = Mn, Fe, Co, Ni) in ferromagnetic ordering

    Band structure calculations were performed for quasi-2D MeO systems using the pseudopotential method within density functional theory. The calculations were carried out within the plane waves methodology using pseudopotentials. Density of electron states was calculated within the approxination of collinear magnetism. We examined the electron structure and estimated the electronic and magnetic properties of FM-ordered quasi-2D MeO systems (Me = Mn, Fe, Co, Ni). It has been demonstrated that the MnO - FeO - CoO - NiO row exhibits a shift in 3d spin down states of the metal relatively to the Fermi level towards the low-energy region. The above affects magnetization in 2D systems of oxides of 3d transition metals. The character of electron density distribution in quasi-2D MeO systems (Me = Mn, Fe, Co, Ni) indicates ionic bond type between the atoms in Me systems. The tendency towards increase of the band gap in the FeO→ CoO→ NiO row has been established. The obtained estimates of the local magnetic moment of a 3d transition metal atom in crystals of examined oxides correlate with experimental data. In conformity with existing views in physics, we have revealed the effect of spontaneous spin polarization of Me 3d and 2p bands of oxygen atoms in quasi-2D MeO systems (Me = Mn, Fe, Co, Ni), which in our opinion plays the main role in generation of magnetic moments in the atoms of 3d transition metal and oxygen.

    Keywords: Density functional theory, pseudopotential mathod, ferromagnetism, electronic band structure, transition metal oxides

  • Energy conservation during treatment of sewage from populated area

    At present an important role in solving energy conservation problem is assigned to thermal pumping plants (TPP). Using processes of evaporation and condensation of easily boiling liquid circulating in the system they extract low potential heat from environmental objects and provide heat supply for buildings, constructions, greenhousee and so on. Artificial sources of low potential heat for TPP of different capacity can be, for instance, ventilation air and exhaust gases, circulating and waste water,ground. Energy efficient reasonability of TPP use in the system of water disposal for the town of Novocherkassk in Rostov region is considered. Calculations indicate that there is a technical potential to replace a boiler house operating on expensive gas fuel and emissing into the atmospere more than 850 t of carbon dioxide - greenhouse gas - with ecologically clean TPP, one of which uses heat of waste water and the other - heat of ground.

    Keywords: thermal pumping plant, renewable sources, energy conservation, evaporation, condensation, waste water, ground

  • Acoustic method monitoring electrochemical processes

    The article describes the research of thermodurability of glass-carbon - one of the most promising carbon materials used in the production of luminophors and semiconductor materials, optical single crystals, etc. The aim of this work was to study the behavior glass-carbon in the course of thermo-cyclic testing. As a method of diagnostics of the birth and development of micro-cracks was used by the reception of signals of acoustic emission. It is shown that at heating in the samples glass-carbon there was a strong movement of dislocations in thermocyclic effects ,recognized in the signals of acoustic emission. As the number of pulses when heated above, than during the cooling of the sample, it is evidence of the accumulation of damages in the structure of the cyclic thermal processing glass-carbon samples. It is established, that the curves of the accumulation of defects at the pulses of acoustic emission, differ on the stage of heating and cooling. Proposed to use the curve of the aggregate accounts of acoustic emission pulses as a possible harbinger of destruction when heated glass-carbon of the product.

    Keywords: acoustic emission, electrodeposition, the activity of the AE, the remote control.

  • Determination of the atomic structure of bimetallic Pt-Ag nanoparticles in metal-carbon catalysts by X-ray absorption spectroscopy data

    The atomic structure of bimetallic nanoparticles of Pt-Ag composition, which are the part of metal-carbon electro-catalysts PtAg/C, is studied by means of EXAFS spectroscopy using the suggested technique. These materials have been prepared by methods of consistent and simultaneous deposition of Ag and Pt atoms from aqueous ethylene glycol solutions of their salts with subsequent acid treatment. The values ​​of the structural parameters of the near environment of platinum atoms are determined. The nature of the distribution of components in nanoparticles is established. Cluster models of nanoparticles are constructed. The fraction of Pt atoms in the working shell and its dependance on preparation methods in each case are determined.

    Keywords: Metal-carbon electrocatalysts, bimetallic nanoparticles, Catalysis, Platinum, X-ray absorption spectroscopy, atomic structure

  • Development of electrooptical device for analysis of motor oil contamination of the internal combustion engine with disperse particles

    A new device is offered for the analysis of motor oil contamination of the internal combustion engine with dispersed particles. Optical and ultrasonic methods for analyzing contamination of motor oils are used to obtain more informative data to estimate the concentration of pollutants in the device.  

    Keywords: tribomonitoring, electrooptical device, the internal combustion engine, motor oils, methods for analyzing contamination

  • Nonferroelectric ceramic of La2-xSrxNiO4 with colossal permittivity

    By self-propagating high-temperature synthesis (SHTS) prepared fine powder оf La2-xSrxNiO4 composition , which is used to obtain dense ceramics exhibiting the properties of n-type semiconductor. Prolonged annealing of the samples resulted in a decrease of the conductivity on the order of 3-4, and the changing nature of the dielectric spectrum: dielectric constant ε' has a stable value of 4·104 Hz in the range of 0,4 − 1·105 Hz .

    Keywords: dielectric constant, phase separation, nikelate of strontium lanthanum, self-extending high-temperature synthesis

  • The determination of cadastral cost of agricultural land taking into account the land limits (charges)

    The article presents a method of accounting land limits (charges) during the cadastral valuation of agricultural land. This allows us to differentiate the cadastral value , depending of presence of protection zone,  water protection zone and on other zones on the  lands. Cadastral cost of agricultural land on the example of Leningrad region counted. Determination of cadastral cost on the basic presented coefficients will reduce the land tax on the territory which include restricted mode zones of use. It will increase the objectivity of cadastral evaluation.

    Keywords: cadastral evaluation of land, agricultural land, land limits, analytic hierarchy process of T.Saaty

  • Method of eliminate empty traffic in TDM technology

    Time Division Multiplexing is the one of the main information transmission technology. Main problem of this method is the large amount of empty of traffic. This number can reach about 97%. In article presents a method for reducing amount of empty traffic by using the new system pointers, that encode information about the frame . Pointer consists of three components : a pointer to a smaller source (points to the source that gave less information ), a pointer to a smaller amount of information and a pointer to the source memory block (points to the memory block , where the frame was formed ). This pointer is generated when creating a frame and is written in the first data slot. After transmitting a frame pointer is decoded, and based on this information, the distribution of data occurs on the output signals. The developed method has several advantages over similar methods of data transmission, does not depend of the speed of data sources, and have minimum depends on amount of input signals. This technology allows to fill information cells only useful information, and improve the efficiency of code up 96.6 %.

    Keywords: Time division multiplexing, traffic reduction, statistical multiplexing, static multiplexing, frame coding

  • Comparative analysis of theoretical and experimental research full-scale arches from glued wood

    The results of testing full-scale triangular arch span 12 m Arch loaded jacks lifting capacity of 20 tons per quarter of the span concentrated forces transmitted through the steel belts to traverse the arch. Arch deformation sensors fixed resistance, dial indicators and deflectometer. According to test results graphs plotted strains, as well as diagrams of normal and tangential stresses.

    Keywords: arch from glued wood, metal triangular wooden arch, full-scale experiments compressed curved elements, brittle fracture.