Home – Home – Jornals – Thermophysics and Aeromechanics 2012 number 4

We consider the structure, composition, and age of Early Paleozoic intrusive associations of the Bumbat-Hairhan area located in the central part of the island-arc system of the Lake Zone, western Mongolia. There are large polychronous plutons (Bumbat-Hairhan and Gundguzin) and small intrusions in this area. We have established that they are composed of granitoid and gabbroid associations of different lithology, ages, and geodynamic nature. The results of U-Pb dating show that granitoid and basic magmatism took place within 551-465 Ma. Two main stages of intrusive magmatism are recognized, which reflect two stages of the geodynamic evolution of the region: island-arc (551-524 Ma) and accretion-collision (511-465 Ma). At all stages, predominant rocks in the region were diorite-tonalite-plagiogranite and plagiogranite associations of calc-alkaline series.

The Sin Quyen Cu-Fe-Au-REE deposit is localized in the Proterozoic deposits of the Phan Xi Pang zone, northern Vietnam. The mineralization is formed by lenticular and sheet-like bodies occurring concordantly with the host rocks. Seventeen orebodies have been recognized in the deposit, which form an ore horizon up to 140 m in total thickness, about 2 km in strike, and up to 350 m in dip. The ores are of simple mineral composition: Au-rich copper and iron sulfides (chalcopyrite, pyrite, pyrrhotite) and iron oxides (magnetite, hematite). Gold and silver are distributed unevenly in the ores: Their contents vary from hundredths and tenths of ppm to 1.8 ppm. Copper sulfide ores are the main concentrator of gold and silver. All ores are characterized by high REE contents, tens and hundreds of times exceeding the element clarkes. The highest contents have been revealed for Ce and La. Orthite is the main carrier of REE. No correlation between REE and ore elements of sulfide-oxide ores has been revealed, which points to the independent formation of the mineralization.
Orebodies together with the host rocks underwent metamorphism at 500-600 to 630-685?C and 3-7 kbar.
The spatial association of the mineralization with amphibolites (metamorphosed basites) and the mineral composition of ores suggest that the Sin Quyen deposit is of Cyprus volcanogenic type.

Gold and silver minerals from the Kupol epithermal deposit, Chukchi Peninsula, were studied. A schematic sequence of mineral formation has been compiled. Specific mineral assemblages have been revealed in jarosite breccias: with native gold, yutenbogaardtite, fischesserite, acanthite, and native sulfur. We considered a possible mechanism of formation of gold and silver sulfides and selenides in volcanogenic deposits: They might have formed during solfatara and postsolfatara processes with the participation of volcanic gases or their condensates and sublimates as well as liquid sulfur (and selenium) and sulfuric hydrotherms produced under the interaction of volcanic gases with meteoric waters. The specific features of the Kupol deposit confirm the solfatara genesis of Au-Ag sulfides and selenides.

The Verkhoyansk-Chukchi orogenic area formed on the vast land mass that had appeared as a result of collision in the Early Cretaceous and that had consolidated the Mesozoic protoorogenic structures in northeastern Asia. This heterogeneous land mass was the basis on which spatially and structurally coupled orogens developed in the late Mesozoic and Cenozoic. The protoorogenic stages in the evolution of the Verkhoyansk-Chukchi area were followed by several large orogenic stages: Albian-Cenomanian, Eocene, and Pliocene-Quaternary. The Okhotsk-Chuckchi volcanic-block and the Yana-Kolyma fold-block orogenic systems formed at stage 1. The Taui-Anadyr' continental-margin rift system formed at stage 2. This shaped the structure of the Verkhoyansk-Chukchi area. The internal structure of the orogenic systems formed through the Pliocene-Quaternary (neotectonic) stage, which was dominated by uplifting throughout the Verkhoyansk-Chukchi area. The neotectonic structure was mostly inherited from the previous orogenic stages.

The paper concerns with mathematical modeling of two-velocity media with reference to data on Stoneley wave propagation at the fluid-porous solid interface from experiments by K.W. Winkler, H.L. Liu, and D.J. Johnson. Models obtained within the limits of two theories, that of Biot (Biot-Johnson) and continuum filtration, are investigated in comparison. On this basis, it is discussed whether it is reasonable to include pore tortuosity and frequency-dependent permeability and tortuosity when modeling the mechanics of deforming fluid-saturated porous solids.

The accuracy (detail, resolution) of controlled-source electrical prospecting is a combination of several disparate elements. They include the model framework used in the interpretation. A real geologic medium has a complex structure. Sedimentary rocks have a layered structure with fractal properties: The layers split into smaller ones. Large-scale geoelectrical studies (for example, electrical prospecting) require a proper geoelectrical model. By necessity, the 1D geoelectrical model in electrical prospecting is horizontally layered, with thick (hundreds of meters) homogeneous layers, whereas a fine structure is neglected. To study some aspects of this problem, we performed a set of numerical experiments. They were aimed at studying the TEM response from a formation consisting of many thin layers with random geoelectric parameters, mainly resistivity.

Growth lines in the mineralized tissues of living and fossil organisms often exhibit regular patterns that record daily, monthly, or annual cycles. Growth laminations in fossil corals and other marine invertebrates indicate long-term deceleration of the Earth's rotation, probably largely due to tidal friction, resulting in a decline in the number of days per year over the Earth's history. Fossils suggest the rate of decline has not been uniform, with the trend between the late Carboniferous and Cretaceous in particular departing from preceding and subsequent periods. However, insufficient data have obscured the nature and cause of the apparent halt in despinning within this time interval. Here we present new fossil geochronometer data that reveal a sustained acceleration in the Earth's rotation in the early Mesozoic Era, lasting about 90 Myr and having led to a decrease in the length of day (LOD) at an average rate of about 3 ms/kyr. The coincidence of this acceleration with certain geophysical events, including the final assembly of Pangaea and a change in the intensity and stability of the geomagnetic field, strongly suggests that its cause is rooted in the deep interior of the Earth. A similar explanation has been proposed for observed decadal variations in the Earth's rotation. Our results suggest large-scale linkage of rotational variation, tectonics, and the geomagnetic field to core-mantle boundary (CMB) dynamics. Furthermore, the newly identified acceleration in the Earth's rotation which began at the end of the Paleozoic and the geophysical factors that are associated with it can ultimately clarify the causal mechanisms of the Permo-Triassic mass extinction.

The problem of laminar flow of a viscous incompressible fluid in a finned circular tube is considered. A solution is obtained in the form of series in eigenfunctions of the Laplace operator; the coefficients in the series are found numerically. For the same problem, a simpler filtration approximation is proposed in which the system of fins is modeled by a radially inhomogeneous porous layer, and fluid flow in it is described by the Brinkman equation. A formula for the effective permeability of the porous medium is obtained by varying the number and height of fins. The formula provides an accurate evaluation of the mean flow velocity and viscous drag coefficient
in finned channels.

Generation of three-dimensional nonlinear waves on a model viscoelastic coating in a potential flow of an incompressible fluid is studied. Periodic nonlinear waves enhanced by the development of quasi-static instability (wave divergence) are considered. The coating is modeled by a flexible flat plate supported by a distributed nonlinearly-elastic spring foundation. Plate flexure is described on the basis of the Karman equations of the theory of thin plates. Perturbations of surface pressure in the potential flow are found in the small slope approximation to an accuracy to terms of the second order of smallness. Numerical simulation reveals a jump-like transition from two-dimensional nonlinear waves to three-dimensional wave structures, which are also observed in experiments.

This paper presents mathematical models for oil-gas flow taking into account the various processes due to the formation of gas micronuclei (microbubbles) in oil: slip of oil relative to the walls of the pore channels (gas lubrication), changes in oil viscosity, and motion of microbubles with respect to oil. We consider examples of oil flow in the near-wellbore zone for the case where a reduction in pressure to the saturation pressure leads to the formation of gas microbubbles and micronuclei and examples of the action of a water-gas mixture in the case where oil foams in the contact area with the injected gas, i.e., a finely dispersed mixture of oil and microbubbles is formed. The behavior of indicator curves for an oil well with the formation of microbubbles is simulated, and the effect of microbubbles on the oil recovery factor in a water-alternating-gas injection process is studied.

A computational algorithm is proposed to determine the reservoir and hydraulic fracture properties from the results of nonstationary hydrodynamic studies of vertical wells. The problem of oil flow to a well intersected by a fracture is solved numerically. Averaged permeabilities are used for cells through which the fracture propagates.

Penetration of distilled water into a clay soil sample saturated by a sodium chloride solution is experimentally studied. Changes in filtration characteristics of soil due to penetration of fresh water and swelling of clay particles, as well as due to the action of an electrical field on the replacement process are quantified. It is demonstrated that electrokinetic processes play a key role at the final stage of replacement of the solution by fresh water. Reasons for the emergence of clay self-polarization potentials owing to violation of electrical equilibrium conditions are studied.

This paper presents the results of experimental studies of the lengthwise distribution of the total and static pressure and the total flow of carbon dioxide in symmetrical neutralizers. These distributions are found to depend on the flow regimes and geometrical characteristics of gas injection. It is established that the density of the gas target per unit gas flow rate increases with increasing portion of the gas injected at the center of the neutralizes.

Pulsed fluidization of a packed bed of a disperse material is studied experimentally and numerically. Mathematical modeling of the process is performed within the framework of the approaches of mechanics of heterogeneous media on the basis of an experimental study of the bed uplift height as a function of the pressure difference in the fluidized bed. A detailed dynamic flow pattern corresponding to one pulse of the experimental setup is obtained numerically, velocity and pressure distributions inside the bed are found, and the maximum height of the bed uplift is determined. The results obtained are demonstrated to be in reasonable agreement with experimental data on the uplift height as a function of the pressure difference.

An analysis is performed to study the heat transfer characteristics of natural convection over a vertical cone under the combined effects of a magnetic field and thermal radiation. The cone surface is subjected to a variable surface temperature. The fluid considered is a gray absorbing/emitting, but non-scattering medium. The boundary layer equations governing the flow are reduced to non-dimensional equations using non-dimensional quantities valid in the free-convection regime. The resulting non-dimensional governing equations are solved by an implicit finite-difference method of the Crank-Nicolson type, which is rapidly convergent and unconditionally stable. Numerical results are obtained for velocity, temperature, local and average skin friction, and local and average Nusselt numbers for various values of parameters occurring in the problem and are presented in the graphical form. Excellent agreement of the results obtained with available data is demonstrated.

The problem of the boiling of a liquid which initially completely saturates a porous medium under a pressure drawdown influence is considered in a planar one-dimensional formulation and a radial self-similar formulation. The influence of the initial state of the medium and pressure drawdown on the filtration boiling process is analyzed. Boiling regimes are identified, and a criterion for distinguishing between these regimes is determined.

Volt-ampere characteristics of the sliding zone of steel-base metal composites in a current collection mode are presented. Friction is implemented at a current density of 100 A/cm2 for the cases of absence and presence of a Pb-Sn melt in the friction zone. An elementary model of rough surface contact is proposed to assess the relation between the area occupied by the melt and the current density. It is shown that the addition of molten low-melting metals is an effective way to reduce the electrical resistance of the friction zone of sliding electrical contact.

The problem of quasi-static compression and spreading (squeezing) of a thin viscoplastic layer between approaching absolutely rigid parallel-arranged plates is solved using asymptotic integration methods rapidly developed in recent years in the mechanics of deformable thin bodies. A solution symmetric about the coordinate axes is sought in the same region of the layer as in the classical Prandtl problem. The layer material is characterized by a yield point and a hardening function relating the intensities of the stress and strain rate tensors . The conditions of no-flow and reaching certain values by tangential stresses are imposed on the plate surfaces. The coefficients at the terms of the asymptotic expansions corresponding to the minus first and zero powers of the small geometrical parameter are obtained. An approximate analytical solution in the case of power hardening and large Saint-Venant numbers is given. The physical meaning of the roughness coefficient characterizing the cohesion between the plates and viscoplastic material is discussed.

The problem of fracture mechanics on nucleation of cracks emanating from circular contours of holes of perforated isotropic solids under longitudinal shear is under consideration. The solution of the equilibrium problem of a perforated solid under longitudinal shear with prefracture zones is reduced to solving an infinite algebraic system and a nonlinear singular integrodifferential equation with a kernel of the Cauchy type. Forces in crack nucleation zones are found by solving these equations. The condition of crack emergence is formulated taking into account the criterion of the limiting discontinuity of material displacements.

Complex deterministic vibrations of a multilayer stack of beams linked only by boundary conditions are considered. A mathematical model of the stack is constructed taking into account the geometric and physical nonlinearities of the beams and the contact interaction of their layers. A method for the study of phase synchronization of vibrations based on wavelet analysis is developed. The influence of boundary conditions for the lower beam and different types of nonlinearity (physical, geometrical, and contact) and their combinations on the character and phase synchronization of vibrations of the multilayer stack of beams is studied.

Based on the analysis of the crack trapping effect of cleavage ridges and penetration of crack front segments in an iron-silicon alloy, the distance between break-through points along a high-angle grain boundary is investigated. If the break-through points are close to each other, the crack trapping effect is dominant; otherwise, the grain boundary separation in break-through windows governs the front transmission process. The relationship between the overall grain boundary fracture resistance and the break-through-point distance is quite complex. The minimum grain boundary resistance is achieved when the break-through points are about 2-3 μm apart, which is also influenced by the grain boundary shear strength, the crystallographic toughness and orientation, as well as the crack front profile.

It is established that the development of a localized plastic strain during compression of samples of rocks (sylvinite, marble, and sandstone) deformed by different micromechanisms has an autowave character. It is shown that the velocity of propagation of autowaves arising in the samples under compression is 10^-5 to 10^-4 m/s (0.3 to 3.0 km/g) and is close to the velocity of slow waves observed in the Earth's crust after earthquakes or rockbursts.

The paper presents the results of the researches made by the Institute of Economics and Industrial Engineering, SB RAS within the program on spatial development launched by the Presidium of the SB RAS. We also put forward a concept of strategizing the Russian spatial development which includes national strategizing and those at the levels of federal districts and RF subjects. We also present our analysis of several development strategies for Siberia and its regions; new optimization model of inter-sectoral regional development; long-term development scenarios for our country and Siberia made by the application of this model; and technique for assessment of spatial transformations. This technique is based on the modeling-methodical complex «SIRENA-2» which includes imitation and normative models of different levels of spatial hierarchy.

The paper presents a brief review of results obtained within the program on «Fundamental Issues of Spatial Development: Interdisciplinary Synthesis» launched by the Presidium of the Russian Academy of Sciences for 2009-2011. It also presents the program on «The Role of the Space in Modernization of Russia: Resource and Socio-Economic Potentials» for2012-2014 -its objectives, goals, list of topics and organizational framework. This new program is notable for its continuity of the previous one and its focus on a dual role the space - as an integrated resource and limited condition of system transformations in the country.

The paper analyzes the institutional conditions and factors of diversification of rural employment and dynamics of the non-standard forms of employment such as temporary and seasonal ones. The analysis of the unemployment, informal employment, and self employment observed in rural areas is also presented. The author offers her classification of the types of employment and definition of a new social phenomenon - the freelance agriculture. The opinions of domestic and foreign experts about of the contours of a modern employment policy are presented too.

The paper considers the current state of proving rural people in the Siberian Federal District with food, and what improvements are required to ensure their higher living standard. We also offer our proposals on how to improve land relations, protect the environment, promote a rural style of life, and ensure a territorial integrity of Russia through usage of full potential of the Siberian agriculture. A proper governmental support to ensure the development of the Siberian agriculture is regarded as a high-priority task.

The paper analyzes the life expectances in the SFD regions by applying the ideas of exogenous and endogenous determination of mortality. The data of recent years concerning death rates arranged by their associated major sets of causes of death showed a positive dynamics in most cases. An average age at death among the SFD population is compared with those observed in the countries characterized by a western model in terms of the epidemiological transition concept. Applying the SFD data, we can show correlations between average ages at death and shares of the deaths and life expectances both for men and women.

The paper presents a theoretical understanding of social factors which determine the young people's preferences to be involved in science or innovation entrepreneurship. We propose a model of young people's incentives for higher their involvement. Applying the surveys of young researches and innovators, we show their attitudes towards science and innovation entrepreneurship, motivations, stimuli and barriers in their innovation activity. We also can state that scientific institutions sufficiently impact on higher young people's involvement.

The paper analyzes how the Russian reform in education influences the development of teaching stuffs at educational institutions. We show the major outcomes and problems of this reform. The analysis of the opinions about modernization of education and its perspectives obtained by our polling the teachers of general education schools in the Bologda Oblast is presented. We also determine how tightly the teachers' attitudes to the reform and factors of Russians' social feeling correlate.

The paper analyzes the influence of monetary policy transmission mechanisms on regional economic development and, in particular, on investments. We consider six-year data for fourteen regions of the Volga Federal District. We identify the factors of monetary policy which should be of a special attention in considering regional specifics.

The paper analyzes what development perspectives for productive forces of the North-East regions would make the deliveries of material resources and goods to these regions higher. The completion of the Amur-Yakutsk Mainline, as well as the projects on construction of a railway towards Magadan and development of a year-round highway network would completely transform a product distribution network connecting with the North-East regions. We present our assessment of feasibility of redistribution of the intra-regional cargo traffic, a pattern of the transport-logistic centers network and zones of their impact. We prove that import-export of material resources and goods can become more efficient should the cargo traffic if redistributed from the river transport to the Baikal-Amur Mainline, railway transport of Yakutia and Trans-Siberian Railway. The growing cargo traffic from the North-East regions will require the reconstruction of these strategic mainlines.

The study considers an issue of the assessment of large-scaled projects. It also presents our statement of the problem under a situation of uncertainty, concept of assessment of regional-transportation projects by applying expert technologies, and numerical illustration of how expected efficiencies of the alternative passages of transportation over the Eastern Bosporus Strait could be assessed at the pre-de-signing stage. We show under what conditions the construction of a bridge connecting the Russky Island could be regarded as a preferential alternative.

The paper offers an approach to support decision-making on selecting an investment project among alternative large-scaled transportation projects. This approach is based on principles of fuzzy set theory. Using this approach, we analyze the competitive projects on construction a bridge connecting the Russky Island. For this purpose we calculate and analyze the costs of alternative projects and their planned timing schedules. We present a cost- risk assessment of a set of timing schedules admissible within network constraints to compute a fussy set of Paretto-optimal plans. We also present our recommendations on how any timing schedule could be corrected.

The difference of current long-term forecasts of coal production in the Kuznetsk Basin amounts to more than a hundred million metric tons. The paper analyzes the internal and external factors which enhance and limit the development of the coal industry in this region. It also discusses a possible niche the Kuznetsk Basin could occupy both in world and domestic markets, and it assess how different scenarios of coal production in this Basin would impact the economic-ecologic situation in this region.

The paper analyzes the territorial zoning for the Samara and Nizhny Novgorod Oblasts within the framework of a space of ecologic-economic and medical-demographic parameters. We consider why the results for each of the territories (an individual approach) and for both areas (a mixed approach) differ. This allows making optimal decisions on reduction of agricultural and industrial pressure.

The paper analyzes methodological approaches to building Russian cities agglomeration and their governance. Here a city agglomeration is considered as one of the forms of inter-municipal economic cooperation. On the base of the data concerning the South Kuzbass agglomeration, we consider the cooperation ties between areas and their shortcomings as such ties were built spontaneously because of the uncoordinated socio-economic policies of municipalities. We offer our recommendations on how to improve the inter-municipal cooperation laws, and topics for further researches on selecting the optimal governance models for the South Kuzbass agglomeration.

The paper analyzes a special status and the basic components and problems of budgetary management of the socio-economic development in megalopolises. A differentiate approach to budgetary management in large cities is considered asmore applicable since it considers their special status. We offer a methodical approach to introducing mechanisms of output budgeting as it allows identifying the interdependence of fiscal indicators and those of the socio-economic development.

The paper analyzes the character and role of company partnership. A theoretical basis of our research is new institutional economics, and an empirical part is based on the surveys concerning the small and medium innovation companies. Our goal is to analyze how innovation activity of such companies depends on their attitudes towards partnerships between them.

Model interpretation of heating and melting processes is analyzed in application to the one-phase statement of Stefan problem in a flat layer of semitransparent material heated from one side, and melted by the radiation-convective method.