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  • Hierarchical classifier constructing problems for radio-photon sensor systems based on addressable fiber Bragg structures

    Radio-photon sensor systems represent a wide range of measurement information systems that use today's standardized parallel and sequential type optical analog chains with filtering, which allows to functionally display information received in the optical range in the radio frequency. One of the main, most widely used elements in the RPSS, which solves the problems of forming, filtering and measuring the conversion of optical radiation, including for the stage of further generation of radio-frequency carriers, is the fiber Bragg grating. The cumulative analysis made it possible to propose for the design of RFSSS a new class of sensors - address fiber Bragg structures (AFBS) constructed on the basis of FBG with two symmetrical discrete phase shifts or two identical FBGs potentially having improved metrological and technical and economic characteristics, as well as enhanced functionality compared with existing, widely used resonance sensors, based on the effects of Bragg and Fabry-Perot in fiber optics. AFBS, by its designation, should become a multifunctional element of the RPSS that act as sensors, formers of two-frequency optical radiation, the basis for generating in each of them a unique difference radio frequency carrying measurement information, which is also the address for their multiplexing. This made it possible to propose a new, separate class of the RPSS, which was named "Radiophotonic sensor systems on adressed fiber Bragg structures", the hierarchical classifier for the creation of which was the main subject of this article.

    Keywords: radio-photon sensor system, addressed fiber Bragg structure, integrated fiber-optic sensor, interrogation, multiplexing, hierarchical classifier of construction problems, system approach

  • Calculation of the efficiency of optical radiation input of DFB and VCSEL lasers into a glass integrated optical waveguide

    The efficiency of optical radiation input of semiconductor lasers of various types into an integrated optical ion-exchange buried waveguide in glass was calculated using optical circuits based on spherical, hemi-cylindrical and hemispherical lenses. Calculations were made by using the method of ray tracing. The single-mode waveguide, used in calculations, is the glass (type K-8) waveguide, made by ion exchange with subsequent burying. The results of the calculations indicate a low efficiency of optical radiation input when using single lenses. The use of a pair of microlenses (collimating and focusing) makes it possible to significantly increase the efficiency of optical coupling, which is 79% for a VCSEL laser. Efficiency of input is limited by a sufficient low aperture of the glass waveguide itself - 0.12. For more precise simulations the race tracing method with wave correction was used. The wavelength of optical radiation for calculations is 1.3 micrometer. The use of a single spherical and cylindrical lens has the advantage for it’s simplicity, but will lead to a serious loss of power in the optical system and, correspondingly, an increase of signal attenuation. This is partly due to reason that when using a single cylindrical or spherical lenses, according to the geometry of the calculations, the optical radiation will not be focused at one point, and essential aberrations take place. Efficiency of coupling with the help of two lenses is limited at first, by numerical apertures mismatch and, at second, partial energy transfer to the rings of Airy disk. The ion-exchange waveguide is suitable for coupling with VCSEL lasers for application in planar waveguide concentrators, etc.

    Keywords: integrated optics, optical waveguides, ion exchange in glass, VCSEL laser, ray tracing method, ZEMAX

  • Methods of synthesis, properties and application of silica-zols for obtaining composite materials Part I

    The article considers examples of obtaining silica sols by ion-exchange methods. An analysis was made of the factors of this method that affect the properties of the resulting sols. The principal technological scheme of an industrial plant for the production of silica-sol by an ion-exchange method were considered. The results of studies of the sol-gel transition in silica-sol obtained by the ion exchange method were presented. The growth kinetics of colloidal silica-sol particles, which were obtained from solutions of polysilicic acid, was investigated. The dependence of the growth kinetics of colloidal particles from solutions of polysilicic acid on the temperature and on the initial pH of the sol was shown. The dependence of the gel time on the dimensions of the colloidal particles in the ash, on temperature, concentration and pH, was shown. The effect of the composition of the liquid phase on the stability of silica sols was established. Influence of the charcoal characteristics on the properties of the xerogels obtained. The effect of silica powder on the properties of the xerogels obtained was analyzed. An analysis of the possibilities of the practical application of silica powder as a binder in the preparation of heat-resistant heat-shielding composite materials was carried out.

    Keywords: silica-sol, ion exchange, sol-gel technology, stability of sols, xerogels, composite materials

  • Methods of synthesis, properties and application of silica-zols for obtaining composite materials Part I

    The article considers examples of obtaining silica sols by ion-exchange methods. An analysis was made of the factors of this method that affect the properties of the resulting sols. The principal technological scheme of an industrial plant for the production of silica-sol by an ion-exchange method were considered. The results of studies of the sol-gel transition in silica-sol obtained by the ion exchange method were presented. The growth kinetics of colloidal silica-sol particles, which were obtained from solutions of polysilicic acid, was investigated. The dependence of the growth kinetics of colloidal particles from solutions of polysilicic acid on the temperature and on the initial pH of the sol was shown. The dependence of the gel time on the dimensions of the colloidal particles in the ash, on temperature, concentration and pH, was shown. The effect of the composition of the liquid phase on the stability of silica sols was established. Influence of the charcoal characteristics on the properties of the xerogels obtained. The effect of silica powder on the properties of the xerogels obtained was analyzed. An analysis of the possibilities of the practical application of silica powder as a binder in the preparation of heat-resistant heat-shielding composite materials was carried out.

    Keywords: silica-sol, ion exchange, sol-gel technology, stability of sols, xerogels, composite materials

  • Influence of the method of introducing additives on the composition and porous structure of Co-catalysts for the synthesis of hydrocarbons

    Three batches of Co-MxOy / SiO2 catalysts were prepared with different methods of introducing an oxide additive. Physicochemical studies of catalysts by elemental analysis and Brunauer-Emmett-Taylor (BET) methods have been carried out. The effect of additives of oxide promoters and the method of their introduction on the specific surface, volume and pore sizes for Fischer-Tropsch synthesis catalysts were studied.

    Keywords: Fischer-Tropsch synthesis, carbon-containing resources, catalyst, active component, silicate carrier, Al2O3 and ZrO2 promoters, elemental analysis, BET method, surface area, volume and pore size

  • Influence of the method of introducing a promoter on the properties of the active component Co catalysts for the synthesis of hydrocarbons

    Using the methods of thermo-programmed reduction (TPV) and thermo-programmed hydrogen desorption (TPD H2), physico-chemical studies of Co-MxOy / SiO2 catalysts obtained by various methods of introducing a promoter additive were carried out. The effect of the introduction method and the nature of the promoting oxide additive on the properties of the active component of the Fischer-Tropsch synthesis catalysts was studied.

    Keywords: Fischer-Tropsch synthesis, catalyst, active component, silicate carrier, Al2O3 and ZrO2 promoters, TPV and TPD H2 methods, crystallite size, degree of reduction, dispersity

  • Methods for solving the problem of crystal-chemical design of composite coatings with anti-friction properties

    The interrelation of tribological properties of composite coatings with the properties, structure and distribution of surface phases, as well as the mechanism of formation of surface phases is discussed.

    Keywords: the structure of crystals, structural phase disorder, tribological properties of the surface phases of the composite coating

  • Self-consistent model of the sol-gel process of film formation on substrates with homogeneous precipitation of particles of hydrated oxides

    This article analyzes the regularities of precipitation of solid colloidal particles of hydrated metal oxides on the surface of various substrates. Two models of this process are proposed. The proposed α-model is a process of continuous nucleation of interaction centers, at random points of a free surface throughout the process. The proposed β-model provides for the instantaneous nucleation of these centers when they are randomly distributed over the entire surface of the substrate. Based on the proposed models, the average values of the following values are calculated: the thickness of the gel film; its roughness and specific surface area. The calculations carried out in the article showed that these parameters are universal functions of the degree of filling of the surface and do not depend on the specific model of the mechanism of the process.

    Keywords: modeling, homogeneous precipitation, formation of thin films, sorbents, catalysts, heat-resistant composites

  • Physical and chemical properties of cobalt catalysts with promoting additives of copper and zirconium

    Physical and chemical properties of cobalt catalysts for Fischer-Tropsch synthesis are investigated. The influence of copper and zirconium oxides on the specific surface area, cobalt concentration, pore volume and size, the degree of reduction of the catalyst Co-Al2O3/SiO2 was studied.

    Keywords: Fischer-Tropsch synthesis, carbonaceous resources, catalyst, active component, silicate carrier, CuO and ZrO2 promoters, elemental analysis, recovery rate, BET method, specific surface area

  • Research of influence of additives on physical and chemical properties of cobalt catalysts of Fischer-Tropsch synthesis

    The study of physical and chemical properties of cobalt catalysts in the synthesis of hydrocarbons by the Fischer-Tropsch method is carried out. The effect of additives promoters NiO, Fe2O3, MnO2, on the specific surface area, pore volume, size of cobalt crystallites, the degree of catalyst reduction is considered

    Keywords: Fischer-Tropsch synthesis, synthetic hydrocarbons, catalyst, promoter, carrier, specific surface area, porous structure, catalytic activity, dispersion, cobalt crystallites

  • Analysis of modern technologies for the use of vacuum and microwave effects in the dehydration of food products

    An analysis of the use of modern technologies based on the use of physical phenomena, namely, vacuum and microwave effects in the dehydration of food products, is given. On the basis of generalization and analysis of studies of domestic and foreign scientists it was shown that these technologies are promising for such plant raw materials as fruits and vegetables, and their effectiveness depends on the characteristics of the raw materials being enriched

    Keywords: vacuum, microwave exposure, dehydration of food, drying

  • Spatial equations of mechanics of composite solid for viscoelasticity models containing in one-dimensional case of two elastic and one viscous element

    For the first time, in the generalization to the spatial case of a one-dimensional viscoe-lasticity model for one viscous and two elastic elements, the stress deviators, deformations, and also the stress and strain rates were used. It is established that the model of a standard viscoelastic body (standard linear solid model) is more universal. The second model cannot be used to solve problems for a weighty body, or dynamic problems, since leads to the solution of an auxiliary physically unjustified boundary or initial-boundary value problem for doubled values of the accelerations. It means that the second model can be applied only to the solution of quasistatic problems for weightless bodies. It is established that the model of a standard viscoelastic body (standard linear solid model) is applicable only to the study of unsteady creep, while the second model is suitable for investigating the steady rheological behavior of a weightless material. Generalization of both models viscoelasticity for composite body was created. The effective Kravchuk-Tarasyuk values of the Poisson ratio, the Young's modulus, and the viscosity of composite material were defined.

    Keywords: deviator of stresses, deviator of strains, deviator of stress rates, deviator of strain rates, viscosity, standard linear solid model

  • Study of the bond strength of zinc electroplating with the surface of the machine parts from gray cast iron by planning a factorial experiment

    To ensure the stability of the galvanic deposition process and the high quality of the precipitate obtained, it is necessary to know the dependence of all processes on technological factors and modes. The degree of influence of technological factors on the behavior of machine parts made of gray iron, etching and deposition of zinc electroplating is not the same, so there is a need for electrochemical studies in the laboratory. The methodology of such studies has a General orientation and particular conditions in each case. The article describes in detail the method of electrochemical studies of gray cast iron in the sulfuric acid electrolyte of galvanizing during the restoration of machine parts by galvanic deposition of zinc coating. The basic conditions necessary for obtaining reliable comprehensive results that will determine the optimal conditions for galvanizing machine parts made of gray cast iron are considered.

    Keywords: technological factor, electrochemical studies, polarization curves, electrochemical cell, electrode, potentiostat

  • A new type of vortex-free flows of helium II in a rotating cylinder

    • Abstract

    Within the framework of the two-fluid Landau theory, flows into helium II inside a rotating cylinder are investigated. Special attention is paid to the analysis of excitation by centrifugal forces of counter-current (by super-fluid and normal components) flows. In the approximation of incompressible fluid, an analytical solution of the equations of motion, vortex-free for both components is obtained. The tangential velocities for it are the same as those of a rotating solid body, with the normal and superfluid components moving in opposite directions, with different angular velocities. It's resulting vorticity is compensated by a spiraled counter-current radical movements. Such solution has no axial symmetry and has a tangential gap along the radius. Despite its instability, it is of some interest. First, it can be corrected by stabilizing deformations. In addition, it shows the paths of loss of stability of high-symmetric States. In particular, in our opinion, this type of disturbance are intermediate flow from Landau (superfluid component is at rest) one to the rotation of the Feynman type (in the superfluid part of a system of vortices).

    Keywords: helium II, rotating cylinder, two-fluid theory, counter-current flows, centrifugal forces, vorticity compensation

  • Determination of the yield stress of the material by static indentation

    For the first time, using the simplest model of an elasto-ideally-plastic coating, a relationship between the Meyer hardness and the absolute value of the yield stress of the material under compression was established for all types of indenters used for static hardness testing. The necessity for an accurate determination of the thickness of the layer in the simplest coating model is eliminated, when using the Prandtl bilinear diagram corresponding to an elasto-perfectly-plastic material as the equation of state. If the linear dimension of the test mark of the hardness is equal to 90 percent of the linear dimension of the total contact area, taking into account the elastic deformations, than the Meyer hardness is the absolute value of the compressive yield strength for the material under compression.

    Keywords: surface hardness, Meyer hardness, yield strength, ball indenter, conic indenter, pyramidal indentor

  • Frequency-asymmetric two-band optical vector spectrum analyzer

    The article deals with the theoretical substantiation and computer modeling of an optical vector spectrum analyzer based on asymmetric optical two-band modulation using a parallel two-channel Maha-Zehnder modulator. The proposed method and device make it possible to achieve twice the measurement range in comparison with the classical optical vector analyzer based on single-band modulation and to realize a simpler and more reliable configuration in comparison with the previously presented amplitude asymmetric optical vector analyzer with two sidebands. It can be possible to measure the frequency characteristics of a fiber Bragg grating with a width of up to 0.5 nm (60 GHz) with a resolution of up to 1 MHz (about 5-10 fm) using electrooptical modulators with a bandwidth of up to 30 GHz.

    Keywords: optical spectrum analyzer, two-frequency modulation, frequency asymmetry, measurement range, fiber Bragg grating

  • Testing "sensor waterscout sm100" to monitor the soil moisture of the subgrade in the actual operating conditions of the road

    This article describes the approbation of the humidity sensor in the real operating conditions of the road. The authors have developed a protective design of humidity sensors that meets the requirements for their laying in the ground floor, developed a mobile portable data reader. The technology of calibration, calibration and laying of sensors in the soil of the roadbed is presented. The analysis of the data obtained after calibration of the sensors.

    Keywords: the soil subgrade, moisture monitoring in the conditions of the road, the humidity sensors

  • The method of rapid diagnosis of diesel engines of automotive equipment equipped with an electronic fuel system

    The article is devoted to the increasing role of new operational methods of Express diagnosis of diesel engines equipped with modern fuel equipment with electronic control, which allow non-destructive testing of technical condition. The method of rapid diagnosis of diesel engines of automotive equipment equipped with an electronic fuel system. Thus, the developed method of rapid diagnosis using a multi-cycle auto scan and diagnostic kit "Tester CR" allows to determine the technical condition of all elements of the power system "Common Rail" for any diesel engine, where such a system is provided, without dismantling the fuel pump and EGF.

    Keywords: Express diagnosis, technical diagnostics, fault, diesel, electronic control unit, fuel equipment, fuel pump, electro-hydraulic nozzle

  • Super resolution in digital holography

    The article considers a method of increasing the resolution of images in holographic systems based on subpixel shift algorithms. Methods of solving systems of equations of large dimension by reducing to block form are considered. The simplest solution is obtained when a set of matrices with an increased resolution is formed from a set of matrices with a shift in one direction, and then the resultant matrix is formed from the resulting set.

    Keywords: super resolution, subpixel shift, holography, solution of systems of equations, holographic interferometry, aperture

  • Techniques for technical diagnosis of cylinder-piston group of diesel engines with cold starting cranking of the crankshaft

    The main disadvantages of the methods of diagnosing the cylinder-piston group used at present are indicated in the article. Mathematical dependencies and the technique of technical diagnosing of a cylinder-piston group of diesel engines with a cold starting cranking of a cranked shaft developed on their basis are offered.

    Keywords: engine, cylinder-piston group, compression,diagnosis, cold idle cranking of the crankshaft

  • Computer model of a fiber-optic sensor for measuring transverse pressure based on a two-frequency optoelectronic generator

    The article demonstrates a computer model of a fiber-optic sensor implemented on the basis of a two-frequency optoelectronic generator (OEG) for measuring lateral pressure. In the loop of the optoelectronic generator, a fiber Bragg grating (FBG) with a phase shift is applied to which a transverse pressure is applied to guide the birefringence and create two orthogonally polarized transparency windows, which leads to the generation of two optical frequencies. The difference frequency of the beats between the two optical frequencies lies in the microwave range and depends on the magnitude of the pressure applied to the FBG. It was modeled that the sensitivity and the minimum detectable pressure are ~ 10 GHz / (N / mm) and 2.5 × 104 (N / mm), respectively. The high frequency and stability of the generated microwave component of the optoelectronic generator provide an extremely reliable and highly accurate measurement. Frequency survey allows the system to operate at high speed. In addition, the measurements are insensitive to changes in the ambient temperature and the wavelength of the optical carrier.

    Keywords: transverse pressure, fiber optic sensor, fiber Bragg grating with phase shift, birefringence, optoelectronic generator, two-frequency optical signal with microwave frequency difference frequency

  • Mathematical modelling of аero-acoustic, fiber optic complex adaptive control

    In the present article the current state and the main problems of nondestructive control methods of working shovels of turbomachines are considered, scopes of nondestructive control methods in a flowing part of turbomachines are defined. The main control methods are considered; the reasons limiting possibilities of these methods are defined; the geometry of shovels, stream parameters, the main defects are defined; are considered hot and cold start-up; gasdynamic control methods are analysed; acoustic control methods, the systems of scanning of a cut of a nozzle are defined; the analysis of systems capable to exercise control of operability of a flowing part of turbomachines is carried out; the mathematical models describing acoustic processes in a flowing part of turbomachines and a way of their improvement are designated. The current state of works on creation of the methods and control devices aimed at improvement of metrological characteristics and expansion of functionality of an acoustic method of nondestructive control of working shovels of a flowing part of turbomachines on a nozzle cut is analysed. For control of working shovels of a flowing part of turbomachines it is necessary to use informative and reliable parameters in complex structure of their understanding. Defects in working shovels of a flowing part of turbomachines are found in operation at surveys by various devices therefore development of the minimum defect to greatest possible can happen for a short time interval that will lead to an emergency. The existing means of regular control прогар shovels don't come to light because of the depth or a sektornost for the reason that defects of motionless parts is insignificant a little influence vibration characteristics of the engine in general. Whereas defects in mobile parts can be revealed also sensors of vibration.

    Keywords: distributed fiber systems, аero acoustic control, acoustic field, process simulation, recovery

  • Mathematical modeling and restoration of optico-acoustic parameters of an air-gas stream on a turbomachine nozzle cut. Results of modeling

    The present article is devoted to development and a research of the distributed fiber systems of aero acoustic control of parameters of an air-gas stream on a cut of a nozzle of turbomachines. The main emphasis is placed on development and to a research of the distributed fiber systems on the basis of control methods the using multiplexed fiber-optical sensors of control of parameters of an air-gas stream on a cut of a nozzle of the turbomachines using advantages of optical methods of information transfer and the device for his realization. The principles of creation of the complex systems of aero acoustic cartography complemented with methods and measuring instruments of gasdynamic parameters of a stream in a flowing part and on a cut of a nozzle of the turbomachines directed to increase in informational content and level of algorithmization of nondestructive control of a condition of working shovels and providing data acquisition in the conditions of parametrical and structural uncertainty of an air-gas stream as on controlled internal sections of a flowing part, and on output section on a turbomachine cut are defined. Problems of placement of points of control and restoration of spatial distribution of the field of measurements in discrete set of points separately are considered. Restoration of the acoustic field of turbomachines is implemented according to measurements at the exit of WATERS, only using statistical approach. Restoration of the field is presented in the form of continuous functions of spatial coordinates by results of measurement in discrete set of points in the presence of aprioristic information on properties of the measured fields. Statistical approaches for determination of coordinates of sensors and an error of restoration on the example of one model problem of control of the field of the radiation created by the continuous exclusive radiator are used. Results of calculations show that existence of correlation between coefficients of decomposition of the field of radiation on functions, leads to reduction, necessary for achievement of the set accuracy of restoration of number of sensors.

    Keywords: distributed fiber systems, аero acoustic control, acoustic field, process simulation, recovery

  • Experimental study of the process of freezing and thawing models of residual bone cavity when cooled with liquid nitrogen

    A method, a device and an experimental model were developed to control the cooling and providing effective low temperatures during cryosurgical treatment of bone tumors. Using the developed device, a range of effective temperatures was determined under the action of liquid nitrogen on the model of the bone cavity. Two ways of cooling the residual bone cavity, instillation and contact, were compared. During the experiment it was proved that the contact method of cryoexposure on the residual bone cavity model is more effective than the instillation of liquid nitrogen according to the characteristics of the temperature field. The proposed experimental model of the residual bone cavity makes it possible to study the temperature field, determine the rate of freezing and thawing both with the contact method and with the instillation of liquid nitrogen into the bone cavity. The results obtained allow to develop preliminary recommendations on the technique of carrying out cryosurgical ablation of bone tumors.

    Keywords: cryoprobe, experimental model, tumors of bones, cryosurgery

  • Application of the coding method for the probe pulse in the model of a distributed fiber-optic temperature sensor based on Raman scattering

    Modern distributed temperature control systems are used today everywhere, in particular, in the telemetry of oil and gas wells. Thus, when creating a distributed fiber-optic temperature sensor based on Raman scattering (DTS) for these purposes, the problem of improving its metrological characteristics always remains urgent. They are in turn determined by the known SNR (signal-to-noise ratio, SNR from English Signal-to-Noise Ratio). To achieve this goal, it is proposed to use a promising method of increasing the SNR in the DTS based on encoding the probing sensor signal by the Hadamard code sequences (simplex coding). For this purpose, a numerical experiment is carried out to implement this coding method using the DTS model and taking into account the noise of the photodetector device. The article presents the simulation results, confirms the effectiveness of the coding method, and summarizes the results of the simulation.

    Keywords: distributed fiber optic temperature sensor, Raman scattering, photodetector device, noise, signal-to-noise ratio, optical pulse encoding, Hadamard code, simplex coding