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  • The study inhomogeneous waves near the boundaries of media

    We study the problems in the propagation of acoustic waves of a sound range near the boundaries of media. The features of the wave processes occurring at the water-air interface, due to the influence of inhomogeneous waves. Considered in detail the properties and parameters of an inhomogeneous plane wave. The mathematical calculations of the transmission coefficients L.M. Brekhovskikh for spherical and cylindrical waves through this boundary, allowing to take into account the contribution of inhomogeneous components. It is shown that than the frequency of radiation of a source is lower and the closer it is located to water-air interface, the acoustic transparency of this border is higher. Study of the dependence of the transmission coefficient of the water-air interface at low frequencies can have important consequences in a number of fundamental and applied problems. Increase the transparency of the interface requires a reassessment of the feasibility of acoustic communication from water in the air, the detection of underwater sources without dipping into the water and acoustic monitoring of the physical processes occurring in the water.

    Keywords: Inhomogeneous plane wave, water-air interface, transmission coefficient, wavelength, spherical wave, acoustic impedance.

  • Change of the mechanism of sintering powders piezomaterials as a way of reducing the temperature of formation of dense ceramic frameworks

    The problem of manufacturing technology heterostructures pezofaza - metal considered in the article. Complexity consists in the fact that during the removal of the polymer in the system at low temperatures are formed porous layers, formed powders separated metal layers, having island macrostructure. One way to solve the problem - reducing the firing temperature heterostructures. Proposed to decrease the sintering temperature by using of functionally active glass-phases. Reducing the sintering temperature of products also allows to replace platinum electrodes inexpensive silver-based alloys. Obtained by solid state reaction method of piezoceramic material has a low sintering temperature (980 ° C) and high electrical parameters. Found that not only the proportion of the vitreous mass, but also their qualitative influence on the properties of piezomaterials    

    Keywords: heterostructure glass phase, the sintering temperature, porosity, ferroelectric phase

  • Change EFP materials PZT system by combining

    Piezoelectric ceramics on the basis of the phase of (1-x) PbTiO3-xPbZrO3 is the basis of most high-performance piezoelectric materials. Electrophysical and mechanical properties of these materials can vary widely in different ways. Traditional methods include changes in composition within the morphotropic region and doping. Now is the study of the influence of topical makrolegirovaniya the material properties of the PZT system. As a model system was selected phase of the PZT system, the compositions of which MO belong, one of which contains a dopant in the sublattice (A) and another - in the sublattice dopants (B). The studies established that one of the effective ways of varying the parameters piezomaterials may be the formation of solid solutions on the basis of two or more piezoelectric phases having different combinations of electrical parameters  

    Keywords: Piezoelectric ceramics, doping, kombinorovanie, pezofaza, piezo

  • A simulation of small scale helicopter using position-trajectory regulator

    In this paper, the synthesis of a trajectory regulator for a mini-helicopter are described. We propose a method to hardware-in-the-loop simulation using simulator AerosimRC. The simulation results are showed. The tasks for the application of the method are pointed.

    Keywords: position-trajectory regulator, helicopter, mathematical modeling, simulation, algorithms.

  • The design's technique of combined drills with replaceable multiface plates

    The technique of the geometrical analysis and the analysis of force loading of combined drills with the replaceable multiface plates is offered in this work. This technique is allowing to determine geometrical parameters and specific force loadings in each point of a plate’s cutting edge taking into account its orientation in the drill case. Application of this technique allowed to establish the reasons of the drill’s low durability. The offered technique allows to design drills from the minimum unbalanced radial component of cutting force which increases its working capacity and the processed holes quality. New designs of combined drills both with two, and with three replaceable multiface plates are offered in this work. The durability of this new drills is increased by the plates mutual turn for the minimization of an unbalanced radial component of cutting force  

    Keywords: combined drill, replaceable multiface plate, drilling, design, equilibration, geometrical analysis, the analysis of power loading

  • Hybrid reverberation algorithm

    A hybrid reverberation algorithm is offered in this article. This algorithm is using both a convolution section in which a convolution with an inmpulse response of a real acoustic room is being implied and a mathematical reverb model. Also an algorithm for generating impulse responses of optional rooms is also offered in the following article. The algorithm efficiency calculation is  specified in the article. Thia reverberation algorithm is a part of a bigger complez auralization algorithm where it is being used coherently with an HRTF-based algorithm in order to simulate a real acoustic environment  

    Keywords: artificial reverb, room simulation, convolution algorithm, impulse response convolution, impulse response synthesis, dynamic convolution, complex filtering

  • Automatic device for analysis the nonlinear parameters of HTSC ceramics YBa2Cu3O7-x in variable magnetic fields.

    Considered part of the software and hardware designed and manufactured the device for the automatic analysis of nonlinear parameters of high-temperature superconducting ceramics YBa2Cu3O7-x in variable magnetic fields. Shows the calibration and specifications. The new is a synchronous (the error in determining the phase of no more than 0.5%) of digital signal samples of the nonlinear response of the sample and the samples generated by an external magnetic field (the error is less than 1%), with the number of data samples per channel to 90 ∙ 106 12-bit samples and sampling 600 ∙ 103 samples per second. The reference range of variable magnetic fields 1 - 50 Oe, a frequency range of 1 - 50 kHz in steps of 1 Hz and the accuracy of 0.0291 Hz. The device has an interface to the computer via two USB-interface and original software to work with it. With the use of the device, a series of experiments designed to produce some non-linear parameters of cylindrical sample made of high-Tc ceramic YBa2Cu3O7-x. The analysis of the results and their comparison with the presented in the literature  

    Keywords: Nonlinear medium, high-temperature superconducting ceramics, synchronous samples, harmonics, ARM-9 CPU, a differential sensor.

  • The synthesis of the concept of the upgraded version of the adaptive friction clutch with a combined feedback

    In a modified version of the adaptive clutch size of the spacer strength decreases due to a reduction of torque, which transmits the additional friction group, including, for the maximum value of the friction coefficient. Therefore, to save the value of the brace force is necessary to increase the ratio usileniya.Predlozhena concept modernized version adaptvnoy clutch with a combined feedback based on the formalization of the distribution of power factors for the closure of the main steam friction of the friction and more friction groups, allows you to simplify the design of the coupling compared to the base case  

    Keywords: the coefficient gain, a separate positive connection, the coefficient of friction, clutch, friction pair

  • The experience of building piled foundations of the piles on nonuniform basis during the construction of a 17-storey residential building in Rostov-on-don

    The article describes the experience of the device of pile foundations under the multi-storey building in difficult engineering-geological conditions in Rostov-on-don

    Keywords: Drilling piles, test, conductor pipe, sandconcrete, foundation

  • Methods for the synthesis of LaMnO3 (Review)

    "This review covers various methods of synthesis LaMnO3 ferroics. The general analysis of the solid-phase synthesis reactions methods and wet methods (sol-gel, sorption, co-precipitation) are carred out. The original results of LaMnO3 syntheses from various precursors by means of the in situ method are showned. The advantages and disadvantages of different methods of synthesis are determined. The analysis of synthesis LaMnO3 ferroics published data is shown:
    - the structure formation of LaMnO3 in perovskite-type phases occurs at different temperatures, depending on precursors states;
    - LaMnO3 perovskite phases differ in symmetry and unit cells parameters at room temperature, depending on the preparation conditions;
    - the highest synthesis temperature of LaMnO3 are typical for solid phase reactions method (950-1050 ° C), the lowest - for wet synthesis methods (500-700 ° C);
     - the synthesis conditions effect the stoichiometry of LaMnO3 for oxygen content.
    Our studies of structure formation processes of LaMnO3 by in situ method are allowed to define the role of precursors states at synthesis of solid phase reactions methods, adsorption, co-precipitation and sol-gel mixtures.
    It is determined that in samples prepared by wet chemical methods, the formation processes of  LaMnO3 perovskite phases occur at lower temperatures than by solid phase reaction (sol-gel precursor - 500 <T <600 ° C; precursors obtained by coprecipitation and sorption methods - at 600 <T <700 ° C and 700 <T <800 ° C, respectively).  

    Keywords: ferroics, LaMnO3, X-ray diffraction, solid-phase synthesis, sol-gel synthesis, sorption, co-precipitation

  • Thermostability of oxide alkali tungsten and molybdenum bronzes

    Oxide bronzes MxEO3 (M–Na,K; E – W,Mo) are the inorganic materials for technics and chemical technology. Its properties, for example stability in wide interval of temperatures, are of great practical interest (electrodes for fuel elements, electronic apparatuses  and others).                                                                             In this article the results of studies of thermostability of sodium and potassium tungsten and molybdenum bronzes in atmosphere and vacuum condition at the temperatures range 20-1110°C were found. The samples are prepared by electrolysis of melts of sodium and potassium isopolytungstates and molybdates. Dates for bronzes Na0.92WO3 , Na0.68WO3 , Na0.53WO3 , Na0.15MoO3, K0.3MoO3 were characterized by the termogravimetric-differential- thermal analysis (TG-DTA). Regions of stability of Na0.92WO3 : 20-700°C , of MxMoO3 : 300-500°C were founded. Conclusion about correlation of  nonstoichiometry of chemical composition of EOx bronzes and oxides, which making important role in formation of less - common metal bronzes structure.

    Keywords: oxide alkali bronzes, tungsten, molybdenum, thermostability, nonstoichiometry, thermal analysis

  • The extent of the stress-strain diagram of eccentrically compressed concrete pillars

    On the basis of experimental data on the resistance of reinforced concrete columns eccentric compression was obtained analytical dependence of the limiting compressibility of concrete from the varied factors: the relative eccentricity of the external force eo / h and the reinforcement ratio μ.

    Keywords: reinforced concrete column, longitudinal reinforcement, a protective layer of concrete, finite element method, critical load

  • Modeling technology changeover

    The paper examines the main approaches to the modeling of scientific and technical progress. Details the conditions and change the model postulates technological structure , its main provisions . Put tasks that are of great interest for scientists involved in the modeling of scientific and technological progress , and for economists who are interested in the practical application of these results . Values ​​of other well-known models of STP . The variants of modernization and the possible synthesis of these approaches to modeling change tehnologichekogo order.

    Keywords: scientific and technological progress, advanced technology, changing technological way of practical experience, the elasticity of factor capital

  • The model predictive control system simulation for the catalytic cracking process of oil

    The especially the functioning of fluid catalytic cracking plant are considered. A mathematical model of a catalytic cracking plant is presented here. Implemented model identification based on experimental data. The predictive controller based on predictive control method for dynamic processes is developed. Effectiveness of the approach is confirmed by the results of catalytic cracking plant simulation. 

    Keywords: catalytic cracking, modeling, model predictive control, multivariate control system, optimization

  • Evaluation of geological hazards and risks of the Eastern Donbass agglomeration

    To the East Donbass agglomeration has developed thematic maps of subsiding soils, indicating their capacity, groundwater levels, surface subsidence above mining, landslide and erosion hazards. Sources of information were the materials of the geological surveys, maps and literature data, and numerical modeling. For the purposes of industrial and civil construction built the final map of the cumulative effects of geological hazards.

    Keywords: geological hazard, modeling, geofiltration,subsidence, landslides, erosion, underflooding, agglomeration.