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Danilenko V.V.,Moscow
Combustion, Explosion and Shock Waves | Year: 2017

The effect of the parameters of a charge of TNT/RDX alloys and their detonation conditions on the coagulation of carbon on the isentrope of the detonation products is analyzed. In the region of liquid nanocarbon, coagulation occurs by coalescence of nanodroplets and in the region of solid nanocarbon, by their joining (sintering) simultaneously with crystallization. Therefore, the specific surface area of nanodiamonds calculated from their sizes is always larger than the measured value. Separation of nanodroplets in detonation products accelerates their coagulation and cooling due to the flow of cooler products around them. Evaluation of the distance between the surfaces of nanodroplets in various TNT/RDX alloys shows that they are small, smaller than nanodroplets. The conditions of rapid coalescence of nanodroplets during different deceleration of the products by rigid barriers are analyzed. An increase of up to five orders of magnitude in the size of diamond particles was established experimentally. The factors responsible for the change in the coagulation rate with the transition from heterogeneous to homogeneous TNT/RDX alloy with decreasing size of TNT/RDX particles are discussed. © 2017, Pleiades Publishing, Ltd.


Morokhovets M.A.,Moscow
History of Medicine | Year: 2015

The article tells us about the life of Professor L.Z. Morokhovets, whose work was closely connected with the Faculty of Medicine of Moscow University in the late 19th and early 20th centuries. Morokhovets’ professional activities were devoted to the service of Russian medicine. To promote Russian science abroad, he founded the Journal of Physiology, which was published in German and French. A significant part of Morokhovets’ scientific and educational activities took place in close collaboration with I.M. Sechenov. As a result, the merits of Morokhovets’ contributions in the development of medical science, medical education and Russian social thought were forgotten, having been overshadowed by Sechenov. Morokhovets was the author of works on the physiology and biochemistry of digestion, and the founder and organizer of the Physiological Institute’s new building at Moscow University, which he equipped with the most advanced facilities for its time. He was the founder of the Museum of Medicine at Moscow University and the author of Russia’s first fundamental guide to the history of medicine. In 1901, Morokhovets proposed to delegate the university’s medical faculty as an independent institution and reasoned his idea. The moral and ethical aspects of doctors’ work were relevant for Morokhovets. He assigned a special place to the role of the physician in society. On the basis of archival material, the author managed to establish new facts from Morokhovets’ biography. It has been demonstrated that the construction of a scientific station on Crimea’s Kara-Dag was a result of the joint activity of two scientists T.I. Vyazemsky and Morokhovets. Previously it was thought that Morokhovets only provided financial support for its construction. In addition, information has been given about the circumstances of Morokhovets’ resignation from the post of head of the department of physiology at Moscow University, and the date of scientist’s death has been verified. © Mikhail A. Morokhovets.


Petrov A.G.,Moscow
Journal of Applied Mathematics and Mechanics | Year: 2016

The plane problem of the potential irrotational motion of an ideal fluid, caused by a cylinder rotating about a fixed axis parallel to the generatrix, is considered. It is shown that the average fluid velocity far from the cylinder decreases in proportion to the fifth power of the distance from the cylinder, and, by a special choice of the position of the fixed axis, in proportion to the seventh power. An exact solution of the problem is presented for an elliptic cylinder. © 2016 Elsevier Ltd.


Soldatenkov I.A.,Moscow
Journal of Applied Mathematics and Mechanics | Year: 2015

Relations between the boundary stresses and displacements are derived for an elastic half-plane with a weakly distorted boundary. To do this, the stress-strain state of the half-plane is expressed by means of two harmonic functions using the general Papkovich-Neuber solution and the distorted half-plane is conformally mapped onto a canonical (flat) half-plane. As a result, a system of boundary value problems for the harmonic functions is obtained from which the required deformation relations follow using a Fourier transform. The effect of the distortion of the boundary on its deformation is analysed. © 2015 Elsevier Ltd. All rights reserved.


Sirotin A.N.,Moscow
Journal of Applied Mathematics and Mechanics | Year: 2015

The problem of the optimal control of the spatial orientation of a rotating rigid body with an axis of symmetry is considered. New geometric properties of the extremals of this variational problem are established in the non-degenerate case. The property of a "collapse" of the extremal field, a ranking alternative and the connection with the family of trigonometric extremals constructed earlier in a similar problem are described in detail. The results obtained are based on an analysis of the system of equations obtained as the result of using the formalism of Pontryagin's maximum principle. The intrinsic non-linearity of the equations of motion in problems of optimizing the control of the reorientation of a rotating body1-5 has led to the development of new approaches assuming additional geometric optimal turning properties. For a non-zero initial rotational velocity, the initial problem reduces to the optimization of successive manoeuvres, that is, the body is first completely decelerated and then reorientated from a position of rest to a position of rest. A new property of the extremals has been described6 in the problem of the optimal control of the reorientation of a rotating spherically-symmetric body. This is associated with the possibility of an abrupt change in the dimension of a certain linear subspace generated by the extremals. It is shown below that similar properties can also be established in the case of the more general problem of the optimal reorientation of an axisymmetric rigid body. © 2015 Elsevier Ltd. All rights reserved.


Bychkov Y.P.,Moscow
Journal of Applied Mathematics and Mechanics | Year: 2015

The rolling without slipping of a body with a rotor on a mobile supporting sphere in a uniform gravitational field is considered. The boundary of the body in the contact area with the support is part of a spherical surface. The central ellipsoid of inertia of the system (body + rotor) is an ellipsoid of revolution, the axis of which passes through the geometrical centre of the sphere, not, generally speaking, coinciding with the system mass centre. The supporting sphere is displaced translationally in an arbitrary way and is rotated around a vertical axis. The complete system of equations of motion of the supporting body and the rotor is obtained. Two integral equations of motion are obtained in the case of a solid of revolution. In the case when the body is a homogeneous sphere, four integral equations of motion are obtained, where the coordinates of the point of contact of the sphere and the supporting sphere are determined by quadratures, and all possible trajectories of the point of contact of the sphere and the body are indicated. © 2015 Elsevier Ltd. All rights reserved.


Maslov L.B.,Moscow
Journal of Applied Mathematics and Mechanics | Year: 2015

A mathematical model and computational algorithm are proposed for the regeneration of bone tissue controlled by a cell differentiation law and the action of an external mechanical stimulus of a periodic character. An extended dynamic model of a changing poroelastic continuous medium and the finite element method in a three-dimensional formulation are the basis of the calculation of the restoration of the elastic properties of bone tissue. The software developed makes it possible to study the processes in the regeneration of damaged bone elements of the human locomotor system with a steady dynamic load and theoretically to substantiate the choice of the optimal periodic action on the damaged tissues for their speediest and stable healing. © 2015 Elsevier Ltd.


Klyachko E.,Moscow
Komp'juternaja Lingvistika i Intellektual'nye Tehnologii | Year: 2015

This paper presents a method for measuring semantic similarity. Semantic similarity measures are important for various semantics-oriented natural language processing tasks, such as Textual Entailment or Word Sense Disambiguation. In the paper, a folksonomy graph is used to determine the relatedness of two words. The construction of a folksonomy from a collaborative photo tagging resource is described. The problems which occur during the process are analyzed and solutions are proposed. The structure of the folksonomy is also analyzed. It turns out to be a social network graph. Graph features, such as the path length, or the Jaccard similarity coefficient, are the input parameters for a machine learning classifying algorithm. The comparative importance of the parameters is evaluated. Finally, the method was evaluated in the RUSSE evaluation campaign. The results are lower than most results for distribution-based vector models. However, the model itself is cheaper to build. The failures of the models are analyzed and possible improvements are suggested.


Bakholdin I.B.,Moscow
Journal of Applied Mathematics and Mechanics | Year: 2014

The results of an analysis of the numerical and analytical solutions of the partial differential equations for different models of continuum mechanics and also the solutions of the ordinary differential equations of the travelling waves for these models are presented. Typical models, the basic theses of the theory of discontinuities in models of the reversible and weakly dissipative type, the classification of time-invariant structures and time-varying ordered structures are considered. The theory includes elements such as the use of averaged equations, evolutionary conditions, conditions for the complete and partial reversibility of a discontinuity, conditions for the existence of a solution in the typical case obtained using dimensional analysis of the invariant manifolds and the number of additional parameters varied and the classification of the periodic waves, solitary waves and kinks with respect to the number of free parameters. © 2015 Elsevier Ltd. All rights reserved.


Kozlov V.V.,Moscow
Journal of Applied Mathematics and Mechanics | Year: 2014

Lagrangian systems with a large multiplier N on the gyroscopic terms are considered. Simplified equations of motion of general form with holonomic constraints are obtained in the first approximation with respect to the small parameter ε = 1/N. The structure of the solutions of the precessional equations is examined. © 2014 Elsevier Ltd. All rights reserved.

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