Valery L. Kovalev

Valery L. Kovalev
Lomonosov Moscow State University | MSU · Faculty of Mechanics and Mathematics

PhD, DrSci. Habil.

About

78
Publications
2,759
Reads
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430
Citations
Citations since 2016
0 Research Items
222 Citations
2016201720182019202020212022010203040
2016201720182019202020212022010203040
2016201720182019202020212022010203040
2016201720182019202020212022010203040
Additional affiliations
September 2011 - present
Lomonosov Moscow State University
Position
  • Head of Laboratory of Nanomechanics
September 1974 - present
Lomonosov Moscow State University
Position
  • Professor

Publications

Publications (78)
Article
Elementary stage rate coefficients of the full system of kinetic equations describing heterogeneous catalytic recombination of the dissociated air on the surfaces of thermal protective ceramic coatings of β-cristobalite and α-Al2O3 are determined using the quantum-mechanical calculations within the framework of cluster models and literature data. B...
Article
Full-text available
The influence of copper impurities on the nucleation of dislocations in aluminum has been investigated using the method for determining the average lifetime of the metastable state. The primary data have been obtained using the molecular dynamics method. The obtained dependences of the dislocation nucleation rate on the shear stress in pure aluminu...
Article
A free molecular gas flow through a membrane vibrating in its plane is studied. Optimal vibration parameters are determined for the most efficient separation of gases with different molecular masses.
Article
On the basis of quantum-mechanical calculations within the framework of the cluster models and the literature data the rate coefficients of the elementary stages of the complete system of heterogenous catalytic recombination of dissociated air on the surfaces of thermal-protective β-cristobalite and α-Al2O3 ceramic coatings are determined. The proc...
Article
Full-text available
The decrease in elastic moduli (Young's, bulk, and shear modulus), the variations in their asymmetries, the Poisson's ratio and the linear compressibility due to carbonate formation in NaX, have been compared to those produced by dealumination of the zeolite HY framework, from the Al-Si-Al fragment positioned in joined 4R rings. All these systems h...
Article
Full-text available
The free-molecular gas flow through the membrane oscillating in its own plane was studied. Passing probability and velocity distribution function of gas molecules in the membrane were calculated depending on the dimensionless parameters characterizing the geometry of membrane channels, gas molecule mass, gas temperature, frequency and amplitude of...
Article
Abstract The free-molecular gas flow through the membrane oscillating in its own plane was studied. Passing probability and velocity distribution function of gas molecules in the membrane were calculated depending on the dimensionless parameters characterizing the geometry of membrane channels, gas molecule mass, gas temperature, frequency and ampl...
Article
Atomic oxygen and nitrogen adsorption on the Si site of the (1 1 1) face of ideal β-cristobalite is studied within the cluster model using the density functional approach. The M06 and B3LYP functionals are found to be the most appropriate for studying atomic adsorption on silica. The calculations show significant difference in adsorption properties...
Article
The oxygen diffusion equation is solved analytically for the case of the coal combustion in a steady-state regime. It is shown that the oxygen concentration essentially depends on the pore geometry.
Article
Full-text available
The possibility of using a high frequency oscillating track membranes as diffusion membranes for gas separation was studied. High frequency forced oscillation of the membrane was considered because of assumption that the membrane conductivity for a given gas can be controlled by varying the frequency and amplitude of oscillation. The problem about...
Article
The self-ignition of an aviation kerosene surrogate by a shock wave is studied. Based on the kinetic mechanisms of fuel surrogate combustion in air, the aviation kerosene ignition is numerically simulated. The shock wave parameters are determined. The induction time dependence on the gas temperature is obtained.
Article
One-dimensional single crystalline TiO2nanorod arrays with different lengths were prepared by control-ling the hydrothermal cycles, which were successfully sensitized with CuInS2quantum dots by assemblylinking cycles, and their optical absorption properties and photoelectrochemical properties were investi-gated. 6 �m-TiO2nanorod electrodes with the...
Article
The effect of ZnSe passivation layer is investigated in the CuInS2 quantum dot sensitized solar cells, which is used to improve the photovoltaic performance. The CuInS2 quantum dot sensitized TiO2 photo-anodes are prepared by assembly linking technique, and then deposited by the ZnSe passivation layer using the successive ionic layer absorption and...
Article
Full-text available
a b s t r a c t Using different computational methods (isolated cluster, periodic models) and levels of DFT theory (hybrid B3LYP, GGA PW91 and PBE, LDA-CA), one obtained an accurate approximation function for the characterization of the band splitting (BS) of symmetric and asymmetric vibrations of the CO 2À 3 anion in cationic zeolite forms. The co...
Article
On the basis of cluster-approximation quantum-chemical calculations of the interaction of an α-Al2O3 surface with oxygen, the rate coefficients for the elementary steps of the heterogeneous recombination of atomic oxygen are determined in the framework of the Eley-Rideal and Langmuir-Hinshelwood mechanisms. For the diffusion layer near the studied...
Article
The adsorption, desorption, impact, and associative heterogeneous recombination rate coefficients are determined for atomic oxygen in the temperature range between 500 and 2000 K on the basis of quantum chemical data on the energy of interaction of atomic and molecular oxygen with the clusters that model an α-Al203 surface. These coefficients are u...
Article
Full-text available
“Lightlike hypersurfaces of a semi-Riemannian product manifold and quartersymmetric non-metric connections” by E. Kiliç and O. Bahadir [KB] is a topic in differential geometry and deals with degenerate submanifolds (degenerate or lightlike hypersurfaces) of a semi-Riemannian product manifold (M, g), which is a differentiable manifold with a tensor...
Article
The paper is devoted to the comparison of different scattering models for molecular hydrogen interacting with a graphite surface. Such problems occur in many applications related to gas–solid problems in high-altitude-vehicle thermodynamics and nanotechnologies. The scattering kernels by Maxwell, Epstein and Cercignani-Lampis are analyzed for diffe...
Article
The results of the molecular-dynamic modeling of hydrogen molecule scattering on a graphite surface are compared with the scattering models of Maxwell, Epstein, and Cercignani-Lampis. The advantages and shortcomings of the above-listed models are analyzed under different conditions. A new scattering kernel is proposed; it represents a combination o...
Article
To analyze the catalytic properties of heat shield materials of space vehicles the cluster model of oxygen atom adsorption on Al2O3 surface is constructed on the basis of density functional theory. The potential energy surface (PES) corresponding to orientation interaction of the O atom with this cluster is calculated. It was found a number of impo...
Article
Full-text available
To analyze the catalytic properties of heat shield materials of space vehicles, the cluster model of oxygen atom adsorption on Al2O3 surface is constructed on the basis of density functional theory. The potential energy surface (PES) corresponding to orientation interaction of the O atom with this cluster is calculated. It was found a number of imp...
Article
The scattering of hydrogen molecules from graphite surface was studied through molecular dynamics simulation. The trajectories of the hydrogen molecules and surface atoms were calculated. The distributions of velocity and energy after reflection were obtained depending on direction and quantity of the initial velocity. The energy and tangential mom...
Article
Full-text available
To analyze the catalytic properties of heat shield materials of space vehicles a cluster model of oxygen atom adsorption on Al2O3 surface is constructed using density functional theory. The potential energy surface (PES) as a function of orientation of the O atom with this cluster is calculated. It was found that there are number of important PES f...
Article
The hydrogen adsorption in carbon nanotubes arrays was studied through molecular dynamics simulation. The interactions are described by the Lennard–Jones potential. The relative mass content and density of hydrogen are obtained as functions of the pressure, temperature and the distance between the tubes in the array. The formation of a second adsor...
Article
On the basis of the molecular dynamics simulation method the trajectories of hydrogen molecules reflected from a graphite surface are calculated with account for its structure and the thermal motion of carbon atoms. The velocity distribution after the reflection is obtained as a function of the velocity magnitude and direction of the incident molec...
Article
A molecular dynamics simulation of the processes of physical adsorption of hydrogen in a carbon nanotube array at temperatures 80–300 K is performed. The relative mass content and density of hydrogen are obtained as functions of the pressure and the distance between the tubes in the array. The cluster geometry optimal for adsorption is found.
Article
Several cluster models of oxygen atom adsorption on an Al2O3 surface are constructed on the basis of the density functional method. The performed quantum mechanical computations allow one to reveal a number of important features of the potential energy surface to describe the heterogeneous catalytic processes with the use of molecular dynamics meth...
Article
To analyze the catalytic properties of heat shield materials of space vehicles, the cluster models of the adsorption of oxygen atoms on aluminum oxide are constructed and the corresponding potential energy surface is calculated on the basis of the density functional theory. Quantum-mechanical calculations showed that it is necessary to take into ac...
Article
Direct simulation method was applied for investigation of hydrogen adsorption in carbon nanotubes. It was shown, that two layers of adsorbed molecules can appear at low temperatures. At room temperature the second adsorption layer wasn't detected. In this case the phenomenological model based on Langmuir isotherm theory was proposed.
Article
The catalytic properties of heat-shielding coatings (β-cristobalite and SiC) used on space vehicles are analyzed on the basis of the microscopic approach with consideration of the molecular structure of the near-surface layer. The heterogeneous recombination coefficient of oxygen atoms and the recombination energy accommodation coefficient are dete...
Article
Using molecular dynamics approach the elementary catalytic heterogeneous reactions on SiO2 or SiC based coatings can be studied in details and all its significant characteristics including both ϒ and β coefficients, distributions of molecules formed during recombination over vibrational and rotational states can be determined. Good agreement betwee...
Article
Full-text available
Using molecular dynamics approach the elementary catalytic heterogeneous reactions on SiO2 or SiC based coatings have been studied in details and all its significant characteristics including both recombination and accommodation coefficients, distributions of molecules formed during recombination over vibrational and rotational states have been det...
Article
Taking both the heterogeneous catalytic processes, including the surface formation of particles with excited internal degrees of freedom, and the processes of multicomponent diffusion and heat transfer in the MESOX apparatus fully into account makes it possible to obtain a recombination coefficient and an accommodation coefficient of the oxygen-ato...
Article
A method of direct numerical simulation is proposed to study the flow and heat transfer in micro-and nanochannels on the basis of molecular dynamics approaches. The distributions of density, velocity, and temperature are obtained for various values of the Knudsen number.
Article
An efficient method of direct numerical simulation is proposed. The steady-state flow field generated by the impingement of a gas jet on a wall is studied as an example. The numerical results obtained during this study are in good agreement with the numerical solutions of other authors.
Article
An efficient method of investigating the processes of interaction between gas mixtures and catalytic surfaces is developed within the framework of classical molecular dynamics. The recombination and chemical-energy accommodation coefficients on the catalytic surface can be determined with fewer computational resources than in the quantum-mechanical...
Article
A dynamic model for the Monte Carlo method is developed to analyze the atom recombination on a catalytic surface. A numerical method for the study of this model is considered. The concentrations of physically and chemically adsorbed atoms obtained using this approach are in good agreement with experimental data and with the numerical results obtain...
Article
The design of aerospace vehicles has required the solution of radically new scientific and technological problems. One of the important problems has been to create reusable heat shield materials. In [1, 2] information concerning the methods and results of solving these problems, including the development of composites from ultrathin quartz fibers a...
Article
This paper is devoted to experimental and numerical predicting of the recombination coefficient gammaO and chemical energy accommodation coefficient beta in the surface-catalyzed oxygen atom-atom recombination based on experiments performed on the MESOX set-up. Experimental results on these two coefficients are presented for silica (cristobalite) i...
Article
A kinetic model of heterogeneous recombination in dissociated carbon dioxide on high-temperature heat-shield coatings is developed; the model takes into account the nonequilibrium adsorption-desorption reactions of oxygen atoms and their recombination in the Eley-Rideal and Langmuir-Hinshelwood reactions. On the basis of a comparison of the calcula...
Article
/RESUME This paper is devoted to experimental and numerical predicting of the recombination coefficient Ogamma and chemical energy accommodation coefficient beta in the surface-catalyzed oxygen atom-atom recombination based on experiments performed on the MESOX set-up. Experimental results on these two coefficients are presented for silica (cristob...
Article
Full-text available
A model of the heterogeneous catalysis of a dissociated carbon dioxide mixture on high-temperature heat shield coating has been developed. The model takes into account both chemical and physical adsorption and desorption of oxygen atoms at vacant active sites on the surface; recombination of chemisorbed oxygen atoms with gas phase of O atoms and of...
Article
A kinetic model of heterogeneous recombination in dissociated carbon dioxide on high-temperature heat-shield coatings is developed; the model takes into account the nonequilibrium adsorption-desorption reactions of oxygen atoms and their recombination in the Eley-Rideal and Langmuir-Hinshelwood reactions. On the basis of a comparison of the calcula...
Conference Paper
A model of the heterogeneous catalysis of a dissociated carbon dioxide - nitrogen mixture on hightemperature heat-shield coatings is developed; the model takes into account nonequilibrium adsorptiondesorption reactions of nitrogen and oxygen atoms and carbon dioxide molecules and their recombination in the Eley-Rideal reactions. On the basis of a c...
Article
A model of the heterogeneous catalysis of a dissociated carbon dioxide — nitrogen mixture on high-temperature heat-shield coatings is developed; the model takes into account nonequilibrium adsorption-desorption reactions of nitrogen and oxygen atoms and carbon dioxide molecules and their recombination in the Eley-Rideal reactions. On the basis of a...
Article
The possibilities of using phenomenological models, constructed on the basis of the ideally-adsorbed Langmuir layer theory, to describe the catalytic properties of the heat shield coatings of reusable hypersonic vehicles are analyzed on the basis of a comparison of the calculated heat flows and the effective catalytic activity coefficients with ful...
Article
The heat exchange on the windward surface of reusable vehicles is investigated. In order to describe the catalytic properties of the surface the Langmuir theory of an ideally-adsorbed layer is used. A comparison of the heat fluxes measured during the second, third, and fifth flights of the “Space Shuttle” with the calculated values indicates good a...
Article
On the basis of an asymptotic expansion of the solution of the equations of a multicomponent chemically nonequilibrium boundary layer for large Schmidt numbers, formulas are obtained for the heat flux and the diffusion fluxes of the reaction products and chemical elements on a surface with arbitrary catalytic activity. The results are compared with...
Article
An effective method is developed for solution of total viscous shock-layer equations on the basis of global iterations by longitudinal pressure gradient and shock wave shape. A new technique of their approximation is suggested and realized that takes into account the function values at all points along longitudinal coordinate lines. The technique a...
Article
An analysis is made of the response of the plasma-projectile system to an abrupt change in current density and to mass injection. Calculations are carried out using the numerical method developed by Zvezdin and Kovalev (1992) for investigating the motion of plasma and the accelerated body. It is found that every case considered involves attenuating...
Article
Changes in plasma parameters and projectile velocity and acceleration in a rail gun during the launch are investigated numerically. The method involves determining the velocity and magnetic induction using a difference scheme and an explicit nonlinear method with flow correction for calculating plasma density. The accuracy of the method proposed he...
Article
The multicomponent chemically reacting turbulent viscous shock layer on a catalytic surface is investigated analytically over a wide Reynolds number range, with allowance made for the nonequilibrium nature of homogeneous and heterogeneous catalytic reactions. The use of the viscous shock layer theory makes it possible to obtain sufficiently accurat...
Article
Turbulent flows past blunt bodies at high supersonic speeds are mainly investigated within the framework of the boundary layer model. However, even at large Reynolds numbers owing to the strong entropy gradient on the lateral surface it becomes necessary to take boundary layer corrections into account in the higher approximations [1]. The use of vi...
Article
An asymptotic expansion of the solution, for large Schmidt numbers, of the system of equations of a chemically nonequilibrium multicomponent boundary layer on the catalytic surface of a blunt body [1] is used to obtain expressions for the diffusion fluxes of the reaction products and chemical elements and the heat flux as functions of the gradients...

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