Home – Home – Jornals – Journal of Mining Sciences 2013 number 4

The article discusses the communication problems within «the current model of the world». In the context of globalization the majority of the institutions of the State are controlled by markets. The subject-ness, preferred by the market, is the «consumer». It is precisely the subject-ness that determines the human activities. The subject-ness of the «consumer» has a fundamental impact on the ability and practice of communication depending on the variability of social forms.

The article reflects the specificities of the professional competence formation of the future specialists in water-supply and sewage on the basis of competence and subject approach with the use of the laboratory practical work. The article represents its model and describes its didactic functions. There are considered the scientific approaches, which are in the foundation of the development of the laboratory practical work. The interconnected stages and principles of its structure are demonstrated. There are revealed particularities in using the laboratory practical work in training of the specialists in water-supply and sewage. There are briefly described the results of experimental approbation in the actual pedagogical process at a technical higher institution. The article presents some methodical recommendations of how to use the practical work in the actual educational practice.

The article is devoted to the topical issues of knowledge control of the students in the traditional and the modern, interactive and competence-based – training methods. The rating estimation of the student activity during the semester considered to be one of the most complex types of evaluation.

The subject of this study is the activity approach, widely used in the third generation state educational standards of higher professional education in resolving the issues of goal-defining of training in the higher education institutions. The author differentiates between the notions of “goal-defining” and “goal-setting” and asserts that the gnoseological potential of the activity approach continues to be actively used in Russia’s social and humanitarian practice. In the article there are distinguished four major trends, in the framework of which the activity approach is applied quite often. Besides the basic characteristics of these trends, their applicability limits are also described. The results obtained in this study have a practical value in dealing with the issues of goal-defining in Russia’s higher education institutions.

The present article deals with the topical aspect of modern higher education, namely, the content, structure and organization of independent work as an integral part of the university curriculum. The primary concern is connected with the role of independent work within the framework of the so-called «competence model». The «competence model» is viewed as an effective means in perfection of the learning skills. The author touches upon the principles of the traditional problem-solving type of the educational process. Different methodological approaches, different kinds of activity, attributes and essential features in connection with the independent student work are presented. The independent student work is regarded as an integral and the most important form of organization of the educational process.

In the article, on the basis of analysis of modern research of the formation of the expert competence, the author presents a model of formation of the military-professional competence of the cadets; the approaches to the creation of such model are described; its functions, its interconnected components (the target-related, content-related, technological, and the result-related ones) and the stages of the competence formation of the cadets of military higher education institutions are revealed.

The purpose of this work is the analysis of influence of the voluntary service on the formation and development of professional competence of the social worker. In the center of attention there is the fact that the voluntary service during the period of higher education alongside with educational activities influences the formation of personal and communicative competences, as well as the social capital. It is noted that the practice during training of social workers is an important component of educational process; however, other volunteer experience is necessary for the future professional. The author claims that today it is necessary to stimulate social activity of students and, first of all, the activity in solving the problems of the society, as the student youth possesses a large present and future potential. In the article it is noted that the higher educational institution can actively participate in the social policy both within the institution and outside it.

In the article there are analyzed the characteristics of the philosophy of education in various philosophical traditions associated with two projects of science and the corresponding two types of rationality. The distinction between the types of rationality, which later led to distinguishing of two science projects, can be traced to Aristotle. They are the sophistic (essentially metaphysical) type of rationality and the dialectical one. In this case, the distinction between two projects (the metaphysical and dialectical ones) is based on the distinction between the types of society, and, consequently, the distinction between the social institutions in them. As a consequence, whether directly or indirectly, the research of the ontological status, axiological and praxeological dimensions of education as a social institution is based on the ontology of the kind of society that the education reproduces. The ontological characteristic of the transformation of education in the contemporary Russia is related to the controversial transition from the former dialectical understanding of education to its interpretation as a service, which is connected with the sophistic type of rationality. Modern education in Russia at the level of rationalities, which are put into the system of education and training, is a mixed sophistic (metaphysical) and dialectical rationality, partially replacing each other. Convergent oscillatory motion of the education system in Russia towards metaphysics and the possible total loss of dialectical framework are the result of the country’s entering the global project of the world transformation based primarily on the globalization of information flows (the informational globalization).

The purpose of the article is to substantiate the idea that realization of free relations, oriented to the “Western model”, is not characteristic to the Russian educational system and, in general, disruptively influences the development of the society, in particular, the social relations. It is proved that free relations include only learning of the individual, are restricted within the framework of law and are realized in the societies of individualistic type. In addition, the paper demonstrates that free relations are characteristic and function successfully in the society of the Western type, which develops within the framework of metaphysical methodology. In the Russian society it is necessary to build perfect relationships based on the principles and standards of dialectical methodology. Introduction into society of the alien social relations leads to appearance of numerous problems in various spheres of public life, including in the field of education.

The vector of journalism education has changed dramatically under the influence of the socio-political and socio-economic transformations at the end of XX – beginning of XXI centuries. Today the priority direction of professional training of future journalists is the organization of the creative activities of students, the creation of conditions for the development of their creative potential and self-expression. The article presents definitions of the notions of «creativity», «creative potential» and «creative personality of the journalist»; the stages are distinguished, the specificities and features are defined of the process of development of the creative potential of the future journalist in the conditions of the creative educational environment conducive to the professional-creative self-realization of personality. The author emphasizes that the development of the creative potential of the future journalist is a lengthy and continuous process, which requires from the teachers a creative approach to the training of future media professionals.

For the first time the article reveals and justifies the essence, content and specific features of the process of self-improvement of the Russian Ministry of Internal Affairs employees in vocational education at the various stages of professional activity. Based on the analysis of the available scientific research on self-actualization, self-development and self-realization, there is defined the category of «self-improvement of the Internal Affairs Ministry personnel» and its correlation with the concepts of«training – self-education» and «upbringing – self-upbringing»; at that, it is taken into consideration that the process of training and education, self-education and self-upbringing are manageable and are a sort of basis for the professional self-improvement of the person. In the paper the author proposed and describes the necessary and effective conditions for the realization of high creative potential of the personality of the employee of the Internal Affairs Ministry in the profession. There are established and developed the conditions for optimal entering the profession, gradual professionalization and professionalism formation, professional fulfillment, which include the phenomena of activity and permanence.

The direct simulation Monte Carlo method is used to study a plane–parallel supersonic gas flow through a grid formed by a series of parallel infinite cylinders. Characteristic features of the shock disturbance formation during the interaction of a supersonic flow with a permeable grid and the effect of this disturbance on the flow parameters behind the grid are revealed. The boundaries of the domain of supersonic flow breakup ahead of the grid and the laws of the total momentum loss on the grid are obtained. Kinetic and energetic characteristics of the flow behind the grid are determined.

Within the framework of a thermodynamically equilibrium model, dynamic loading of mixtures of two and more condensed phases with different properties within the experimental error is described by using species parameters only. The behavior of alloys considered as mixtures with the same volume fractions of the species is studied. The behavior of condensed phases for solid and porous materials is described with the use of the equation of state of the Mie–Grüneisen type and with allowance for the dependence of the Grüneisen coefficient on temperature. The calculated results are compared with experimental data and available calculated results in wide ranges of parameters.

The natural frequencies and modes of seiche oscillations in a closed water reservoir consisting of a long narrow channel connected to a wide basin were investigated theoretically and experimentally. Calculations were made using linear shallow-water theory in two-dimensional and one-dimensional formulations. The spectral properties of free-surface oscillations at points lying on the nodal lines of the first four modes of seiche oscillations were studied experimentally. The one-dimensional model adequately predicts lower-mode frequencies, but the data on the positions of the nodal points of seiche oscillations obtained using this model are somewhat different from those obtained experimentally and using the two-dimensional model.

An exact solution of the magnetohydrodynamic equations is constructed which describes steady vortex flow in a stationary cylinder on the axis of which a conductor carrying a known current is located. The solution is obtained under the assumption that the fluid is viscous and has finite electrical conductivity and that the magnetic field has only the axial and azimuthal components in a cylindrical coordinate system. It is found that the action of the Lorentz force is compensated by changing the pressure. Fluid flow occurs from the periphery to the axis of the cylinder under a pressure gradient, with flow rotation and swirling. The fluid flow causes a concentration of the magnetic lines near the axis of the cylinder, providing an exponential decrease in the magnetic field strength with distance from the axis. This flow can be considered as a model of a local increase in the magnetic field strength due to the transfer of its force lines by the flow of the electrically conducting fluid.

A flow of a viscous incompressible fluid in a deformable tube is considered. Solutions of unsteady three-dimensional Navier–Stokes equations are obtained for low-Reynolds-number flows in the tube (under the condition of small deformations of the wall): generalized peristaltic flow and flow with elliptical deformations of the vessel walls. At small unsteady deformations of the tube walls, the solutions satisfy the equations and boundary conditions with an error smaller than the tube wall deformation level by an order of magnitude. In the case of elliptical deformations of the vessel, the solution agrees well with experimental data.

The flow structure and statistical features of a turbulent stable stratified boundary layer are studied by using the Reynolds-averaged Navier–Stokes (RANS) scheme of turbulence, which takes into account the influence of internal gravity waves. The possibility of the RANS description of intermittent turbulence both near the surface and above the surface in the vicinity of the low-level jet flow formed above the boundary layer is analyzed. The role of turbulent diffusion (third-order statistical moments) in intermittent turbulence generation is discussed. Numerical results are demonstrated to agree with results of LES modeling and actual observations. Intermittency of turbulent kinetic energy both near the surface and above this surface in the vicinity of the low-level jet flow is revealed.

The effect of passive porous coatings of different lengths on the second mode of disturbances in a hypersonic boundary layer is considered. The experiments are performed in a flow with a free-stream Mach number M_∞ = 5,8 and five values of the unit Reynolds number around a sharp cone with an apex half-angle equal to 7°, which is aligned at a zero angle of attack. One half of the model surface along its generatrix is covered by a porous material, and the other part is a solid surface. Pressure fluctuations on the model surface are measured. It is found that application of a passive porous coating can either decrease or increase the amplitude of the second mode. The length of the passive porous coating corresponding to the maximum efficiency of its action on flow disturbances and the coating length that increases the amplitude of the second mode are found.

The problem of flutter of viscoelastic rectangular plates and cylindrical panels with concentrated masses is studied in a geometrically nonlinear formulation. In the equation of motion of the plate and panel, the effect of concentrated masses is accounted for using the δ-Dirac function. The problem is reduced to a system of nonlinear ordinary integrodifferential equations by using the Bubnov–Galerkin method. The resulting system with a weakly singular Koltunov–Rzhanitsyn kernel is solved by employing a numerical method based on quadrature formulas. The behavior of viscoelastic rectangular plates and cylindrical panels is studied and the critical flow velocities are determined for real composite materials over wide ranges of physicomechanical and geometrical parameters.

An experimental and numerical analysis was performed to investigate the laminar regimes of conjugate thermogravitational convection in a closed parallelepiped with heat-conducting walls of finite thickness in the presence of a local energy source with convective heat exchange with the environment. The numerical studies were performed using the Fluent software. The experimental data and numerical results agree well each other.

The Eulerian and Lagrangian approaches are used to perform a numerical study of the disperse phase dynamics, turbulence, and heat transfer in a turbulent gas–droplet flow in a tube with sudden expansion with the following ranges of two-phase flow parameters: initial droplet size d₁ = 0–200 μm and mass fraction of droplets M_L1 = 0–0.1. The main difference between the Eulerian and Lagrangian approaches is the difference in the predictions of the droplet mass fraction: the Eulerian approach predicts a smaller value of M_L both in the recirculation region and in the flow core (the difference reaches 15–20%). It is demonstrated that the disperse phase mass fraction calculated by the Lagrangian approach agrees better with measured data than the corresponding value predicted by the Eulerian approach.

Using the equation of living forces averaged over the volume of the filter and obtained from the Navier–Stokes equations of an incompressible fluid, an analytical formula for the permeability coefficient in the classical Darcy problem is derived to within the principal terms of the Poiseuille number. It is shown that the resulting permeability coefficient is inversely proportional to the square of the specific surface area and the dimensionless average dissipation rate of the kinetic fluid energy in the filter.

A local-interaction model describing the penetration of axisymmetric projectiles into sandy soil at a constant velocity is studied experimentally and theoretically. Two approaches to the determination of the parameters of the quadratic local-interaction model are considered. The first approach is based on the use of the solution of the problem of spherical-cavity expansion taking into account the dynamic compressibility and shear resistance of soil. In the second approach, model parameters are determined based on the experimental dependence of the resistance to penetration of conical projectiles into a sandy soil on the impact velocity. Good agreement was obtained between the results of experiments, two-dimensional numerical calculations, and calculations for the local interaction model based on the solution of the spherical-cavity expansion problem and used to determine the maximum resistance to penetration of conical and spherical projectiles.

The resonant frequency of flexural vibrations for a double tapered atomic force microscope (AFM) cantilever has been investigated by using the Timoshenko beam theory. In this paper, the effects of various parameters on the dimensionless frequency of vibrations of the AFM cantilever have been studied. The differential quadrature method (DQM) is employed to solve the nonlinear differential equations of motion. The results show that the resonant frequency decreases when the Timoshenko beam parameter or the cantilever thickness increases, and high-order modes are more sensitive to it. The first frequency is sensitive only in the lower range of contact stiffness, but the higher-order modes are sensitive to the contact stiffness in a larger range. Increasing the tip height increases the sensitivity of the vibrational modes in a limited range of normal contact stiffness. Furthermore, with increasing the breadth taper ratio, the frequency increases. The DQM results are compared with the exact solution for a rectangular AFM cantilever.

A method is developed for determining the load-bearing capacity of ice plates, which are modeled by an ideal rigid-plastic plate located on an incompressible foundation. The plate with a simply supported or clamped arbitrary smooth curvilinear contour is subjected to a load uniformly distributed over an arbitrarily shaped reinforced local central region. An analytical expression for the ultimate load is derived. A plate shaped as an ellipse is considered as an example.

A method is proposed to study the distribution of residual stresses in a semicircular notch in a hollow cylindrical specimen after advanced surface plastic deformation. The initial information used in the method is one or two experimentally determined components of the residual stress tensor in the hardened layer of the smooth specimen. The problem is solved using a finite element technique taking into account initial plastic strains, which are set in correspondence to the residual stresses according to the laws of elasticity. The effect of the hardening technology and notch depth on the distribution of residual stresses is studied. Experimental verification of the method showed that the calculated and experimental data on the stress distribution over the depth of the layer are in good agreement.

The problem of the interaction of surface and flexural-gravity waves with a vertical barrier is solved in a two-dimensional formulation. It is assumed that the fluid is ideal and incompressible, has infinite depth, and is partially covered with ice. The ice cover is modeled by an elastic plate of constant thickness. The eigenfrequencies and eigenmodes of oscillation of the floating elastic ice plate, the deflection and deformation of ice, and the forces acting on the wall are determined.

The condition of mutual nonpenetration of the crack faces is proposed for a Timoshenko plate with an oblique crack, whose initial state is defined by a surface the normal to which makes a small angle with the middle plane. Unique solvability of the variational problem of plate equilibrium with the nonpenetration conditions for the crack faces specified on the curve describing the crack is proved. A differential formulation of the problem equivalent to the original formulation for sufficiently smooth solutions is proposed. For the one-dimensional case (beam with a cut), an analytical solution is obtained, and the cases of longitudinal tension and compression are examined.

The mechanical properties of notched samples of St.10 steel under tension at different strain rates were studied. Fracture surfaces of the notched samples after the dynamic bending were investigated, the mechanisms of plastic deformation and fracture were determined, and the fractal dimension of the fracture contours were obtained.

The effect of stiffness of shock-absorbing pads of a real explosion chamber on the degree of vibration damping and maximum stresses in the body of the camera is experimentally and numerically investigated. The results are analyzed. A relation between the seismic effect on the foundation after a charge explosion inside the chamber and durability of its operation is revealed.

The article gives the experimental proof of effective use of the kinematic criterion χ, derived by Oparin for “apparent” velocities of pendulum waves based on deterministic description of seismic energy release in the Norilsk mine fields, for assessment of stresses and strains in coal beds in terms of the Polysaevskaya Mine, Kuzbass.

Based on numerical modeling of stress–strain state of rocks and the in situ deformation monitoring of rocks mass surrounding underground excavations, the authors determine limit criteria of geomechanical stability of mine structural elements in terms of the Aikhal Mine where mining has been transferred under the worked-out open pit bottom. Using the determined criteria, the stress–strain state and subsidence of the crown pillar are assessed, considering current stage of the water table in the open pit. The article gives predictive estimate of the change in the stress–strain state and subsidence of the crown pillar upon the water level raising.

The regular patterns of initiation and show of acoustic emission memory effect in a composite are experimentally obtained using cloth laminate. The authors illustrate capacity of cloth laminate as an absolute sensitive stress-to-acoustic emission converter. The designed and tested downhole sensor enclosing this converter provides indication of incremental stress excess over pre-assigned critical limit.

The article reports the integrated assessment of natural stresses in rock mass in the Nurkazgan Mine. The visual observation of underground excavations and instrumental measurements of effective stresses denote the hydrostatic stress state within the studied minefield

The issues of physico-mechanical properties of ore and rocks, measurement of displacements in rock mass around underground excavations, stability of the excavations, selection of types and parameters of supports are studied in terms of the Yakovlevsky iron ore deposit

Out of aspects of modeling mathematically deformation of rock specimens, the article analyzes soft and rigid loading. The authors formulate an inverse problem on identification of mechanical properties, boundary conditions and geometry of weak areas using overspecified conditions using data on measured displacements and acoustic-electromagnetic emission that characterizes rock failure under loading.

Based on the review of the strongest mining-induced rockbursts with the same seismic characteristics recorded in underground mines in Russia, the author compares the events based on their energy parameters. It is shown that the mining-induced seismic events on the Kola Peninsula are still the strongest events.

The article presents and discusses a quasi-brittle rock failure model, analytical expressions constructed for limit stresses using necessary and sufficient criteria of structured rock failure, normal tensile stresses in rock mass with fracture, quasi-brittle failure diagram constructed using approximation of two-section kinked stress–strain curves obtained in coal under tension, and critical stress estimates.

Mining complexes can contain multiple mines operating simultaneously along with multiple processing streams, stockpiles and products. Stochastic optimization methods developed to date generateonly local optimal solutions in the sense that they do not consider the entire mining complex. This paper presents an extension of a multi-stage method used for generating long-term risk-based mine production schedules, to operations with multiple rock types and processing streams. The developed method uses a simulated annealing based algorithm during the optimization stage, seeking to minimize deviations from production targets for waste and different ore processing streams. The proposed approach is applied at Escondida Norte copper deposit, Chile, in which sulphide, oxide, mixed and waste materials are present with milling, bio-leaching and acid-leaching being the available processing streams. The stochastic schedule generates expected deviations from mill and waste production targets smaller than 5%, which avoid indirect costs associated to idle capacities. A schedule generated conventionally exhibits expected deviations of the order of 20%.

The authors report experimental research and in situ study of oxidation and ignition factors in opencast mining of fire-hazardous ore. The article makes recommendations on spontaneously flammable ore extraction and storage as well as prevention of endogenous fires and fire protection in sulfide ore stockpiles.