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ASA scholars 2010
 
  1. Name: Yana Arakcheeva
    Photo of Yana Arakcheeva
    Place of work: Moscow State University Geological faculty, Departament of Engineering and Ecological Geology
    Date of birth: 24.01.1989
    Research title: The assessment of stress levels in the rocks from geothermal fields by means of acoustic emission (AE).
    Main results:

    On the basis of the Kaiser effect and felicity ratio in rocks of geothermal deposits features of rocks properties, and in particular stress memory are studied. For this purpose core samples of Oceansky geothermal deposit located on the Kurils are investigated. Whole volcanic massive is transformed under the action of thermal waters. In the section boreholes distinguished different zones of hydrothermal treatment. Tests and measurements AE are carried out at the uniaxial compression. The research problem was to try to identify the behavior of acoustic emission (AE) in the rocks of these zones with different structural and petrophysical properties and remove the preserved information on levels of stress that existed in the array. Using the methods of acoustic emission was detected several stress levels: some of the gravitational stress and stress associated with the different zones of hydrothermal overtime.

    If the gravitational stresses in the samples with of shallow depths values correspond to about 30% strength in uniaxial compression, a confident characteristics of the stress by AE can not be given. This is due to intense acoustic emission in the initial stages of loading at the close of defects in the rock. Starting from the depths below 350 m gravitational stresses are found. In this case the gravitational stress was recorded in different zones of hydrothermal overtime. In addition, the high stress in coerse-grain tuffs of zone of opalites, occurring near the surface, were observed with the help of AE. However, these strains are not associated with a state of stress of rock mass, but with the destruction of openwork (due to high porosity) frame strong enough of the mineral-frame opal. In this case, there is a sharp increase in the intensity of AE during uniaxial compression. In zones of hydrothermal argillites and argillized propylites high content of clay minerals increases the porosity. This leads to the fact that the rock samples from these zones have a reduced activity of AE during the test. Of particular interest are represent the rock of band "boiling." The levels of stress are not able to recover in all samples. This is due to the lack of stress deviator or very small size of its in zones with the hydrostatic state of stress. Established fact in good agreement with earlier findings, L.L.Panasyan et al (2000) on Ocean hydrothermal deposits. In the vein dyke formations of andesite and diorite composition regardless of the depth of their location in areas of treatment revealed a number of species of high levels of stress. Presumably this is due to the introduction of strains of the dyke complex.

    Main publications:
    1. Panasyan LL, Ladygin VM, Frolova YV, Krivosheeva ZA Elastic anisotropy of metasomatic deposits steam hydrothermal Ocean field // Vestnik Moskov. Univ. - Ser.4. Geology. - 2000. 1 - p. 47-54.
    2. Arakcheeva Ya. the Comparative characteristic of Quaternary and Neogene basalts of Sredinniy ridge of Kamchatka/Engineering researches in building. Proceedings of scientifically-practical conference of young experts ` 2008. - : PNIIIS, 2008.-119 p.
  2. Name: Galina Gracheva
    Photo of Galina Gracheva
    Place of work: Taganrog Institute of Technology, South Federal University, Department of Electrohydroacoustical and Medical Engineering, Faculty of Electronics and Electronic Equipment Engineering
    Date of birth: 03.11.1986
    Research title: Research of far field features of spherically convergent and divergent sound beams.
    Main results:

    The goal of the work was theoretical and experimental investigation of spherically convergent and divergent sound beams. A number of features in the far field zone of both focused and defocused radiators were discovered. It was proved based on the parabolic equation that the feature of both convergent and divergent beams is the ability to change qualitatively the far field structure by means of value d0. Here, d0 = ka2/2R0 is the dimensionless curvature of a radiator surface; k is the wave number; a is the radiator radius; R0 is the curvature radius. This feature is caused by interference of Fresnel zones, the number of which depends on d0. In case of even number of Fresnel zones, the wave amplitude is equal to zero in the paraxial area of a beam for uniform amplitude distribution along a radiator surface. In case of odd number of the zones, the amplitude is maximum. Besides, in case d0 = 2pn, the wave amplitude distribution along the acoustic axis in the far field zone has a slope minus 40 dB per decade whereas it is equal to minus 20 dB per decade for a radiator with curvature of d0 = p0(2n-1).

    For carrying out experiment the focusing and defocusing piezoelectric transducers both with the radius of curvature R0 = 74 mm, the aperture radius a = 22 mm and the resonant frequency of w0/2p0 approximately equal 840 kHz were made. The results of the theoretical studies were compared with experimental measurements and found in good agreement. The research in medium with gas bubbles showed the break of the condition of the wave amplitude minimum on a beam axis because of medium heterogeneous. This suggests using the results for developing of new methods for medium heterogeneous diagnostics.

    Main publications:
    1. Gracheva G.M., Gavrilov A.M., Sitnikov R.O. Experimental research of an acoustic field of a spherically convex radiator. Proceedings of the XX Session of the Russian Acoustical Society, Moscow, GEOS, 2008, vol. 1, pp. 182 - 185.
    2. Gracheva G.M., Gavrilov A.M., Sitnikov R.O. A variety of a far field structure of a spherically converging wave beam. Proceedings of Southern Federal University. Engineering science. Thematic edition "Ecology 2009 - the sea and the person". Taganrog, TTI SFU press, 2009. no. 6(95), pp. 65 - 71.
    3. Gracheva G.M., Gavrilov A.M., Sitnikov R.O. Features of a far field of spherically converging ultrasonic beam. Proceedings of the XXII Session of the Russian Acoustical Society and Session of the Scientific Council of Russian Academy of Science on Acoustics, Moscow, GEOS, 2010, vol. 1, pp. 233 - 236.
    4. Gracheva G.M., Gavrilov A.M., Kuzmin I.M., Sitnikov R.O. Field structure research of a focusing radiator of ultrasound. Proceedings of Science Conference "Session of the Scientific Council of Russian Academy of Science on Acoustics and XXIV Session of the Russian Acoustical Society", Moscow, GEOS, 2011, vol. 1, pp. 194 - 198.
  3. Name: Alexandr Karabutov
    Place of work: Moscow State University
    Research title: Laser ultrasonic investigation of laminate disbonding.
  4. Name: Konstantin Kurashkin
    Photo of Konstantin Kurashkin
    Place of work: NNB IMASH RAS, RUSSIA, Nizhny Novgorod
    Date of birth: 26.10.1986
    Research title: Developments of acoustic method of measurement of mechanical stress in elements of constructions taking into account a structural condition of material.
    Main results:

    As a result of studies of acoustoelastic effect in the welded joint of steel K11506 (steel 09G2S) under uniaxial tension the dependence of acoustoelasticity coefficient from the distance to the weld was obtained. The acoustoelasticity coefficient is expressed through the elastic modules of second and third order. Modules of third-order, which determine non-linear elastic properties of material, depend on its structural state. The heterogeneity of elastic properties of heat affected zone is the reason for the difference between the values of the acoustoelasticity coefficient at points distant from the weld at various distances. The dependence of the acoustoelasticity coefficient from the distance to the weld should be considered for evaluation the stress condition of the of the welded joint material.

    An algorithm for determining residual stresses in the welded joints in the mode of a nonzero acoustic tensometry was proposed. Using the proposed algorithm allows to make the operational control of residual stresses in the welded joints directly on the object by measuring the propagation time of bulk elastic waves.

    The technique is based on the separation of loaded and unloaded areas of material using analysis of Poisson's ratios, measured by acoustic pulse echo method. It was established that there is a linear relationship between Poisson's ratios v31 and v32 in rolled material at the absent of residual stresses. This is due to the peculiarities of formation of the rolling texture of sheet. The presence of residual stresses leads to deviation points {?31; ?32} from the straight. The value of the deviation can be used for estimation the level of stress. The algorithm was tested on a pipe of gas main.

    Acoustic studies of pipe element of gas main with longitudinal and circumferential welds were performed. Analysis of the results of measurements of Poisson's ratios allowed to separate sections of material, where residual welding stresses present and where stresses absent, and to estimate value of stress in the mode of a nonzero acoustic tensometry. Axial and circumferential residual stresses near welds were calculated through the relations of acoustoelasticity. The obtained results are in good agreement with theory.

    Main publications:
    1. Kurashkin K.V. Mishakin V.V. Investigation of the influence of material's structure on acoustic parameters // Transactions of Nizhny Novgorod state technical university n.a. R.Y. Alekseev. - 2011. - 2(87). - P. 190-198.
    2. Kurashkin K.V., Mishakin V.V. Estimation of residual mechanical stresses in welded joints by acouctic method // Proceedings of the XXIV Session of the Russian Acoustical Society. - M.: GEOS, 2011. - .II. - P. 15-17.
    3. Kurashkin K.V., Mishakin V.V. Using the structural heterogeneity of the material in the evaluation of mechanical stresses // Applied Mechanics and Mechanical Engineering. Proceedings. - N.Novgorod: publishing " Intelservis ", 2010. - 2(17). - P. 230-235.
    4. Kurashkin K.V., Mishakin V.V. About the possibility of using structural characteristics of the material for realization of nonzero acoustic tensometry // Applied Mechanics and Mechanical Engineering. Proceedings. - N.Novgorod: publishing " Intelservis ", 2010. - 2(17). - P. 236-242.
    5. Kurashkin K.V., Mishakin V.V.The use of ultrasonic waves to estimate the mechanical stresses in the material of weld joints // Proceedings of the XXII Session of the Russian Acoustical Society. - M.: GEOS, 2010. - . II. - P. 106-110.
  5. Name: Elena Kuznetsova
    Place of work: Marine Technical University of St.Petersburg
    Research title: Scattering of stationary and non-stationary (impulse) sound signals by a choppy sea surface.
  6. Name: Dagzama Makarova (Tsydenova)
    Photo of Dagzama Makarova (Tsydenova)
    Place of work: Buryat Scientific Centre of Sib. Div. of RAS
    Date of birth: 04.06.1982
    Research title: Acoustical research of viscoelastic properties of polymer liquids.
    Main results:

    Real shear modulus and effective viscosity of polymer liquids in dependence on angle of shear deformation and temperature has been measured by an acoustical resonance method. It was shown that the real shear modulus and effective viscosity, calculated by rheological Maxwell's model, are decreased at shear deformation increasing. Region of linear elasticity observed at low shear angles, where shear stress is proportional to shear deformation. Shear modulus are decreased and tangent of mechanical loss are increased at deformation angle increasing. It was suggested that liquid has a structure in linear elastic region remain constant and are breaking at shear deformation increasing. The theory of cluster formation and disintegration in polymer liquids has been assumed.

    Main publications:
    1. Damdinov B.B., Barnakov Yu.A., Dembelova T.S., Tsydenova D.N. About opportunity measurements shear mechanical properties of liquid different // Izvestiya Vuzov. Fizika. - 2006. - 3. P. 22-23.
    2. Sanditov D.S., Damdinov B.B., Badmaev B.B., Tsydenova D.N. About cluster model of viscoelastic matter // Proceedings of XX session of the Russian Acoustical Society. V.1. - M. GEOS, 2008. P. 117-122.
    3. Dembelova T.S., Vasil'ev A.A., Tsydenova D.N., Budaev O.R. Acoustical investigation of viscoelastic properties of polymer liquid PES-2 depending on temperature // Proceedings of XX session of the Russian Acoustical Society. V.1. - M. GEOS, 2008. P. 122-126.
    4. B. Badmaev, T. Dembelova, B. Damdinov, D. Makarova, O.Budaev, Influence of surface wettability on the accuracy of measurement of fluid shear modulus// Colloids and Surfaces A: Physicochem.Eng.Aspects 383 (2011) 90-94.
  7. Name: Daniil Milogradsky
    Place of work: Moscow State Institute of Radiotechnics, Electronics and Automatics (Technical University)
    Research title: Estimation of the dispersion of neural pulse numbers evoked by identical signal presentations.
  8. Name: Vitaly Popuzin
    Place of work: Research Institute of Mechanics and Applied Mathematics, Southern Federal University, Rostov-on-Don
    Date of birth: 03.07.1985
    Research title: The Fast Fourier methods in short-wavelength diffraction of elastic and acoustic waves.
    Main results:

    Many problems arising in the high-frequency diffraction cannot be solved analytically, so the standard approaches apply one of numerical techniques to find the solution. When the problem is reduced to the system of integral equations via Boundary Integral Equation (BIE) method and then discretized, this leads to the linear algebraic system with the dense matrix which can be solved by classical Gauss-elimination method in O(n3) arithmetic operations. However, such matrices have special structure which permits effective algorithms of matrix-vector multiplications in such a way that it needs only linear instead of quadratic arithmetic operations. Thus, such types of techniques are used in iteration schemes where matrix-vector multiplication is the most expensive computational operation. If the iteration scheme converges rapidly, then the total cost to solve the initial problem is nearly linear depending on the size of the mesh. These compression methods are well studied, so in our current research we are concentrating on a certain improvement of the iterative schemes. We develop new iterative algorithms where on each iteration step one should solve an approximated problem with a special matrix. This is performed in such a way, that the initial matrix becomes Toeplitz after having applied this approximation. In the case of elliptic obstacle it can be done analytically by constructing a linear algebraic system on the circle. In this case the matrix is circulant and the form of its exact inversion is known and can be achieved by applying Fast Fourier Transform which requires O(N*logN) arithmetic operations. In the case when the obstacle has more general form, and the approximate matrix is computed numerically by a certain averaging method. Then a bi-conjugate gradient method is applied to solve the approximate system with the Toeplitz matrix by nearly linear amount of arithmetic operations. Similar idea to construct the iteration scheme is applied in the diffraction problem for the system of linear obstacles. The algorithm developed shows fast convergence for respective second-kind Fredholm integral equation. Three papers presenting the results of this sort are currently submitted for publication - two of them - to Western journals, the third one - to a leading Russian journal.

    Main publications:
    1. Sumbatyan M.A., Popuzin V.V. An efficient numerical algorithm for one-dimensional diffraction integral // Russian Izvestiya. North-Caucasus region. Series of natural sciences, 2009, No.5.
    2. Popuzin V.V. Application of the FFT to solve integral equations in mechanics of continua // Proc. of international school-conference of young scientists "Mechanics 2009". 28 Sep - 1 Oct 2009, Aghavnadzor, Armenia: EGUAS, 2009 , p. 292-296.
  9. Name: Vera Romanova
    Photo of Vera Romanova
    Place of work: Nizhny Novgorod State University Radiophysical faculty, Departament of Acoustics
    Date of birth: 31.12.1987
    Research title: Construction of robustness algorithms for adaptive low-frequency acoustic monitoring in ocean.
    Main results:

    Accuracy of reconstruction of the layered structure of the sea bottom is studied as a function of the spectrum-correlated and statistical structure of noise and interference measured in the experiments on seismoacoustic sounding of the Caspian sea bottom. The possibility of using the decision statistics optimized with respect to the statistical structure of interference for estimation of the parameters of the observed sea-bottom irregularities are analyzed. One of the requirements for engineering seismoacoustic work in the shelf areas is that the negative effect of high-power seismoacoustic sources of explosion type on the ocean ecology should be minimized. However, a decrease in the power of explosion sources leads to constraints on the seismic prospecting efficiency in the sea since the accumulation of useful signals from such incoherent pneumatic, spark, and explosion seismoacoustic sources is low-effective, because of the low reproducibility and low coherence. The studies showed that the resolution and depth of seismoacoustic sounding required for the solution of practical problems can be reached with the use of wideband coherent hydroacoustic sources. The radiation power of such sources is not high. Nevertheless, due to the high coherence of the radiated signals, the required efficiency of seismoacoustic sounding can be reached by accumulation of signals. The use of hydroacoustic sources opens up good prospects for adaptation of characteristics of the receiving-radiating subsystems of a seismoacoustic profilograph to observation conditions and employment of effective methods and algorithms of signal and aperture synthesis.

    The possibilities of using coherent hydroacoustic sources for seismoacoustic sounding of the sea bottom were studied in the experiments in the Caspian sea during underwater towing of the receiving-radiating complex with the help of a research vessel. Accuracy of the sea-bottom reconstruction during sounding by coherent seismoacoustic sources can be increased by using decision rules optimized with respect to the statistical structure of interference. Measurements show that the tower noise is a set of components of different nature. Each noise component is localized in its frequency range and has temporal features inherent in it. Coherence and statistical structure also turn out to be different for each spectral component. Different robustness algorithms for adaptive signal processing were produced in several programming environments. It follows from research that when sounding seismoacoustic signals are used in different frequency ranges, estimation of the layer position can be more reliable if decision statistics optimized with respect to the statistical distributions of the corresponding noise components is employed. In particular, as such statistics, one can use the Lp norms. During reconstruction of low-contrast layers, as well as the layers located at fairly large depths and the signal from which is weak, an efficient method for estimation of the layer depth is use of decision statistics on the basis of a neuron-like medium with free dynamics and context-dependent parameters. The use of such decision statistics ensures specified confidence of the layer-depth estimates during observation of signals whose level is by 5-10 dB lower than the level required for the same confidence, but when the classical matched filtering is employed.

    Then, the coherent trajectory accumulation (aperture synthesis) of pulses reflected from each observed layer takes place during seismoacoustic sounding of the sea bottom with allowance for the empiric model of the layer-depth variation during correction of variations in the relative position of the towed source and the receiving array. Such an algorithm of accumulation ensures adaptive coherent spatio-frequency focusing of signals to each layer, thus making it possible to improve the sounding sensitivity by 40 or more decibels.

    Main publications:
    1. Khobotov AG, Romanova VI, Khilko AI. Choice of criteria for check of hypotheses during low-mode acoustic tomography of the ocean // Proc. of the Nizhny Novgorod Acoustic Scientific Session of May 13-14, 2008, N.I.Lobachevsky State University, Nizhny Novgorod, 2008. - pp. 128-130.
    2. Smirnov IP, Khilko AI, Romanova VI. Optimal extraction of mode signals against the noise background by vertical arrays in plane-layered waveguides // Izv. Vyssh. Uchebn. Zaved., Radiofiz., 51, No.1, 2008. - pp. 50-62.
    3. Lazarev VA, Malekhanov AI, Merklin LP, Romanova VI, Talanov VI, Khilko AI. Experimental studies of the possibilities of seismoacoustic sea-bottom sounding by coherent low-frequency pulses // Basic research of oceans and seas, Nauka, Moscow 2010. - pp. 300-314.
  10. Name: Mikhail Salin
    Photo of Mikhail Salin
    Place of work: Institute of Applied Physics RAS
    Date of birth: 23.01.1987
    Research title: Research of influence of surface wave on the time and spatial (azimuth) characteristics of acous-tic reverberation in case of ton signal propagation on the shallow water.
    Main results:

    In case of waveguide propagating of an low-frequency acoustical signal on stationary shal-low paths, scattering of the signal on the surface waves leads to broadening of a temporary spec-trum of a signal and broadening of the spatial spectrum (in case of signal reception on the hori-zontal array). Estimation of levels of reverberation of this kind is needed for determining of pre-cision in near field acoustic holography problems and for estimation of performance of low fre-quency hydroacoustic systems.

    An optical method of measurement of time-spatial wind waves spectra was developed, suc-cessfully realized and tested within this project. The method is based on 1) processing of a video record of the surface of an area about 10x10 wavelengths (of most powerful waves) in order to obtain non-calibrated 3d spectrum (by frequency and wavenumber) of the surface roughness and 2) its following calibration and transformation into real units basing on a reference 1d (fre-quency) spectrum measured in real units in a point inside or near the video record area.

    Analytical formulas for evaluation of the reverberation levels and patterns, which use par-ticularly the time and spatial spectrum of wind waves, were derived. We obtained an satisfactory agreement of reverberation levels, that were directly measured in the experiment (carried out by bistatic scheme) and calculated, basing on surface roughness characteristics, obtained in the same experiment. In case of monostatic scheme (back scattering), an expression for local (per unit area) tar-get strength of surface roughness at Doppler frequencies was derived. This expression was ob-tained on basis of a certain surface roughness spectrum, which was measured in shallow sea, but it (expression) is rather common, due to similarity of surface roughness spectra in saturation area. The obtained result is more general that the previous formulae because it gives the Doppler spectrum of the scattered signal.

    Main publications:
    1. E.L. Borodina, M.B. Salin. Estimation of Space-Time Characteristics of Surface Roughness Based on Video Images // Izvestiya, Atmospheric and Oceanic Physics, Vol. 46, No. 2, pp. 239-248 (2010)
    2. B.M. Salin, M.B. Salin. Methods of calculation of low-frequency surface reverberation at know characteristics of surface roughness // Acoust. Phys. 57. Vol.57, No. 6, pp. 833-842 (2011)
    3. M. B. Salin. Measurement of surface waves characteristics by video shooting of the spar buoy // Proc. of XX session of Russian acoustic society. Vol. 2, Moscow, GEOS, 2008, pp. 32-35
    4. B.M. Salin, M.B. Salin, R.C. Spindel. Investigation of the Influence of Wind Waves on the Spectral and Angular Characteristics of Sea Surface Reverberation from a CW Source // Pro-ceedings of MTS/IEEE OCEANS, Seattle, USA, 2010
    5. B.M. Salin, E.L. Borodina, M.B. Salin. Estimation of surface reverberation and characteris-tics of wind waves based on the analysis of video images of the sea surface // Proc. of XXII session of Russian acoustic society. Vol. 2, Moscow, GEOS, 2010, pp. 305-308
    6. M.B. Salin, E.L. Borodina, B.M. Salin. Calculations of reverberation levels and patterns, based on measured surface roughness field: theory and experiment // Proc. of Forum Acusti-cum 2011. Aalborg, Denmark. P. 2519-2524.
  11. Name: Yuliya Nikolaenko (Savich)
    Photo of Yuliya Nikolaenko (Savich)
    Place of work: Dep. of Hydroacoustics and Medical Engineering, Southern Federal University Taganrog Institute of Technology
    Date of birth: 25.07.1988
    Research title: Modelling and researching vibrodiagnostic system for rolling bearings monitoring.
    Main results:

    The necessity of investigation rolling bearings as vibrating system gives some advantages for the vibrodiagnostic sphere, especially for high-machinery units like trains, gas and oil pressure units. Rolling bearing is the object for diagnosing and is the source of the signal, which is measured by the vibrodiagnostics system. But not always we have an opportunity to receive the certain signal which is the most interesting for investigation. Thus it is useful to model the vibrodiagnostic signal. Furthermore it would be convenient while designing the vibrodiagnostics system for special aims.

    The math model of the "The local roughness of the outer collar" defect type had been obtained. It had been made by using the Lagrange equation 2 genera and considering the distance between the bearing rings. The signal relation investigation indicates the limited applicability of the math equation, but in the certain interval the equation is the acceptable and could be the model of the "The local roughness of the outer collar". In such a way it's possible to model the other types of bearing defects and to study signal properties. Such signals could be used during investigation the constructed vibrodiagnostics system for the modifying purposes. The model of vibrodiagnostics system had been constructed in Simulink/MATLAB, but previously electric structural scheme and schematic diagram of the developed rolling bearing vibrodiagnostics system had been analyzed. The practical significance of the results are vibration signal models, that could be used as samples in simulation stands for educational purposes, the principles of vibrodiagnostics system constructing can be applied for simulation the virtual vibrodiagnostics system, which can be useful for vibrodiagnostics practice training for education.

    Main publications:
    1. A.N. Kutsenko, Y.V. Savich, D.S. Slutskiy. Acoustic tract of monitoring system of early diagnostics for ecological safety provision of moving train bearings // Taganrog: Proceedings of the SFU. Technical sciences, 2009. 7(96). - pp.41-49.
    2. Yulia V. Savich. Technical diagnostics of rotor equipment in oil and gas industry, Taganrog, 2010 // Science week-2010: Thesis book - Taganrog: SFedU, 2010.
    3. Yulia V. Savich. Selecting the information about the state of rolling bearing by the frequency analysis of vibration, Taganrog: Proceedings of X scientific conference of students and post-graduate students "Technical cybernetics, radio electronics and control systems" - 2010. - Volum 2. p.71.
  12. Name: Evgeniy Shchipunov
    Place of work: Tomsk state University of Control Systems and Radioelectronics
    Research title: Phonetic analysis of Russian, English, and Arabic languages using psychoacoustic model of the human acoustic system.
  13. Name: Alexander Shikhabudinov
    Photo of Alexander Shikhabudinov
    Place of work: Institute of Radio Engineering and Electronics, RAS, Saratov Branch
    Date of birth: 03.01.1981
    Research title: The study of acoustic and dielectric properties of nanocomposite materials.
    Main results:

    The acoustic and dielectric properties of nanocomposite materials based on the matrix of low-density polyethylene with embedded nanoparticles of various metals and their compounds have been investigated. For this purpose the special technique for searching the material constants of thin polymer nanocomposite films such as elastic modulus and viscosity coefficient was developed and tested. This technique is based on the use of piezoelectric resonators with a longitudinal electric field. Optimal conditions for obtaining samples of polymer nanocomposite films from powdered material were found. It was found that the mold temperature about 110 ? C is optimal for achievement the minimum porosity or maximum density of nanocomposite films based on high-density polyethylene with aforementioned nanoparticles. The analysis of the theoretical results obtained in the framework of the one-dimensional linear chains showed that with increasing the density of the material nanoparticles longitudinal elastic modulus decreases, as observed experimentally. The studies have shown that in all cases, the acoustic impedance of the pointed above nanocomposites is less on the 2-2.5 orders compared to the corresponding impedance for the well-known piezoelectric crystals. Besides the possibility of the purposeful change of the acoustic impedance of the nanocomposites in the range about 40% by the change in the concentration and material of the nanoparticles was shown. The effect of the temperature on the permittivity of polymer nanocomposites with different percentage of iron nanoparticles was also investigated. It was found that with increasing the temperature the permittivity in all cases decreases. At that the value of the permittivity and its variation with temperature depends on the concentration of nanoparticles in a polymer matrix. The obtained results demonstrate the possibility of practical application of nanocomposite polymer materials with different content of iron nanoparticles and iron oxide as a low-impedance matching layers and as layers for development of thermostable piezoelectric structures.

    Main publications:
    1. Zaitsev B.D., Kuznetsova I.E., Shikhabudinov A.M., Ushakov N.M., Kosobudskii I.D. Acoustical characteristics of polymeric nanocomposite films // Int. Congress on Ultrasonics, April 9-12, 2007, Vienna, Austria. Program and Abstracts, p.166; 2007.
    2. Zaitsev B.D., Kuznetsova I.E., Shikhabudinov A.M., Kolesov V.V., Fionov A.S., Petrova N.G. Temperature dependencies of dielectric permittivity of polymeric nanocomposite materials // Int. Conf. AMAAV'09, Jan. 4-6, 2009, Cairo, Egypt, Book of Abstracts, p.57, 2009.
    3. Kuznetsova I.E., Zaitsev B.D., Kuznetsova A.S., Shikhabudinov A.M., Teplykh A.A., Borodina I.A. The use of nanocomposite polymeric materials for optimization of acoustic gas flowmeter parameters // Int. Congress on Ultrasonics, Jan. 11-17, 2009, Santiago, Chile. Program and Abstracts, p.20, 2009.
  14. Name: Andrey Shmelev Place of work: Moscow State University, Department of Acoustics, Faculty of Physics Date of birth: 01.05.1985 Research title: Tomography of acoustical nonlinear parameters special distribution based on the third order nonlinear effects.
  15. Name: Andrey Shmelev
    Photo of Andrey Shmelev
    Place of work: Moscow State University, Department of Acoustics, Faculty of Physics
    Date of birth: 01.05.1985
    Research title: Tomography of acoustical nonlinear parameters special distribution based on the third order nonlinear effects.
    Main results:

    Nowadays the role of ultrasound introscopy has the great importance for the medicine because of its effective and efficient methods of diagnostic imaging. The majority of ultrasound systems give the information about linear acoustical parameters such as sound velocity, density, attenuation of the media. However researches of nonlinear characteristics of biological tissues of different authors have shown that nonlinear parameters contain very important diagnostic information, because they are more sensitive to the pathological changes than linear parameters.

    The proposed tomography scheme is based on the nonlinear effect of three noncollinear primary acoustical waves interaction, which has been considered theoretically. The result of this interaction is the scattering of combinational waves to the third order. These waves contain the information about the second order and the third order nonlinear parameters, which are responsible to the square and cube terms of equation of state expansion correspondingly. The main advantage of this tomography scheme is the possibility of reconstruction of the total nonlinear parameters special distribution of the sample using just three transducers and one receiver. Such an opportunity is possible due to coding the primary acoustical waves and the following matched filtering of the received scattered combinational sygnal. Despite the fact that the effect of three waves interaction is extremely weak, the great noise stability of such schemes with correlation processing makes it possible to use this effect for the tomography purpose. It is also shown theoretically that the reconstruction of the information about the third order nonlinear parameter of a media is possible only due to noncollinear tomography schemes, such as, for example, the proposed scheme. The numeric modeling of the tomography process, has shown the huge potential opportunities of this scheme. The first physical experiments have proved the possibility of using the third order nonlinear acoustical effects for the tomography purpose.

    Main publications:
    1. Burov V.A., Shmelev A.A. Numerical and physical modeling of the tomography process based on third-order nonlinear acoustic effects // Acoustical Physics, 2009, V. 55, No. 4-5, P.482-495.
    2. Burov V.A., Evtukhov S.N., Shmelev A.A., Rumyantseva O.D. Tomography of spatial distribution of scatterer in nonlinear processes of the second and third orders // Nonlinear Acoustics - Fundamentals and Applications (Proceedings of 18th International Symposium on Nonlinear Acoustics). Edited by B.O.Enflo, C.M.Hedberg, and L.Kari (American Institute of Physics, Melville, New York, 2008). P.440-443.
    3. V.A. Burov, A.A. Shmelev, O.D. Rumyantseva. Numerical and physical modeling of tomography process based on third-order nonlinear acoustical effects // Acoustical Imaging. M.P.Andr. Ed. J.P.Jones, , H.Lee. New York: Springer. 2011. V.30. P.379-388.
  16. Name: Andrey Storozhenko
    Place of work: V.I.Il`ichev Pacific Oceanological Institute of the Far Eastern Branch of the Russian Academy of Sciences
    Research title: Research on small-scale inhomogeneities in the shallow sea using sound scattering methods.