Home – Home – Jornals – Contemporary Problems of Ecology 2016 number 3

Diapirism can be regarded as the main mechanism of transport through the lithosphere for both felsic and mafic/ultramafic magmas. However, the lack of field observations makes it difficult to identify the key mechanism responsible for the formation of dome-shaped structures. In this study, emplacement of natural diapirs is reconstructed by numerical experiments handling realistic rheological and petrological models for the crust and mantle lithosphere. Three different regimes of diapiric ascent were established depending on the chosen model rheology: (1) single-stage diapir ascent; (2) pulsating ascent of successive batches of mantle-derived magma to the base of the crust with a periodicity of 2-3 Myr; (3) emplacement of extensive magma bodies in the form of sills either beneath the base of the crust (underplating) or to deeper mantle levels. The timescale of 30 Myr for a heat source at the base of the lithosphere is sufficient to initiate the ascent of a diapir through the mantle and crust. The study provides the estimates of rheological properties of the lithosphere and partially molten material at which diapiric ascent through the mantle and crust can occur.

Laboratory and numerical experiments simulating the heat transfer and flow structure of thermochemical mantle plumes provide insights into the mechanisms of plume eruption onto the surface depending on the relative thermal power of plumes, Ka = N / N ₁, where N and N ₁ are the heat transferred fr om the plume base to the plume conduit and the heat transferred from the plume conduit to the surrounding mantle, respectively, under steady thermal conduction. There are three main types of plumes according to the Ka criterion: (i) plumes with low thermal power (Ka < 1.15), which fail to reach the surface, (ii) plumes with intermediate thermal power (1.15 < Ka< 1.9), which occur beneath cratons and transport melts from depths below 150 km, wh ere diamond is stable (diamondiferous plumes), and (iii) plumes with a mushroom-shaped head (1.9 < Ka < 10), which are responsible for large intrusive bodies, including batholiths. The volume of erupted melt and the depth from which the melt is transported to the surface are estimated for plumes of types (ii) and (iii). The relationship between the plume head area (along with the plume head diameter) and the relative thermal power is obtained. The relationship between the thickness of the block above the plume head and the relative thermal power is derived. On the basis of the results obtained, the geodynamic-regime diagram of thermochemical mantle plumes, including the plumes with Ka > 10, has been constructed.

Studies of primary multiphase silicate inclusions in accessory Cr-spinels from the fine-grained dunites of the Nizhnii Tagil Pt-bearing massif reveal their similarity to melt inclusions trapped by chromite during its growth. The analyzed Cr-spinels with multiphase silicate inclusions differ in composition from ore chromites of the same massif and from chromites (with melt inclusions) from ultramafic oceanic complexes but are similar to Cr-spinels in dunites from Pt-bearing alkaline ultramafic massifs (Konder and Inagli). According to petro- and geochemical data on heated multiphase silicate inclusions, the studied Cr-spinels crystallized with the participation of subalkalic picrobasaltic melts similar to the magmas of the Konder Pt-bearing massif and having almost the same chemical composition as tylaites. The differences between the compositions of olivines formed within the multiphase silicate inclusions and of the rock-forming minerals show that the studied Cr-spinels formed from an intercumulus liquid melt in the olivine crystal interstices during the cumulate crystallization of most of the Nizhnii Tagil massif dunites in the intrusive chamber. Numerical modeling based on the compositions of heated multiphase silicate inclusions in accessory Cr-spinels demonstrates that olivines and Cr-spinels from the studied dunites crystallized at 1430 to 1310 ºC and then olivine formation continued to 1280 ºC during the evolution of melts.

We present results of investigation of the trace-element (REE, HFSE) and Hf isotope compositions and U-Pb age of single zircons crystallized from alkaline-carbonatite magmas of the Ilmeny-Vishnevogorsky complex (IVC) (Urals, Russia). It has been established that the geochemical characteristics of the early zircon (U-Pb age is 430-410 Ma) from alkaline rocks and carbonatites of this complex are determined mainly by the magmatic evolution of parental fluid-saturated alkaline-carbonatite melts and, to a large extent, are associated with the cocrystallization of zircon and uranium rare-metal minerals (gatchettolite and pyrochlore) at the final stages of the magmatic-system activity. Early IVC zircons have a moderately depleted Hf isotope composition (εHf from +11.3 to +4.7), confirming the mantle nature of the magma source and indicating the participation of DM-like and enriched-source (probably, lower-crust component) substances in the magma generation. The considerable variations in the initial Hf isotope composition of the early zircons testify to the multistage zircon crystallization involving new portions of melts with different isotope compositions related to mixing of substances at their source. Late IVC zircons (250-350 Ma) have strongly disturbed «rejuvenated» isotope systems and a geochemical composition different from that of the magmatic zircons. They formed apparently at the metamorphic stage without a substantial input of additional material.

We present nomenclature and geochemical classification of Paleoproterozoic LILE-enriched high-Mg low-Ti mafic-granitoid rocks of the eastern margin of the Sarmatia paleocontinent and substantiate their tectonic position. Two differentiated rock series are recognized: 1) biotite-orthopyroxene melanorite-quartz-meladiorite-melagranodiorite and 2) hornblende-biotite quartz-diorite-tonalite-granodiorite. Both series correspond in chemical composition to calc-alkalic gabbro-diorites, diorites, tonalites, and granodiorites. As follows fr om their mineralogical and geochemical compositions, these are norite-diorite rocks (intrusive analogs of boninites) (SiO2 = 52-65 wt.%, MgO = 5-20 wt.%, TiO2 = 0.2-0.8 wt.%) and high-Mg granitoids (SiO2 = 60-70 wt.%, Na2O/K2O = 0.65-1.33, MgO = 3.23-7.4 wt.%, K2O = 1.9-4.0 wt.%), respectively. Their high Mg# values (67-87) and Cr contents (>100 ppm), on the one hand, and their isotope-geochemical characteristics similar to those of the host metaterrigenous rocks, the magma enrichment in LILE, and the presence of Ni sulfide ores with a predominance of light sulfur isotopes, on the other, testify to crustal contamination of mantle magmas. The rock series are nearly of the same age and belong to the same magmatic system, wh ere high-Mg granitoids are differentiates of parental high-Mg (boninite-like) norite-dioritic magma. This is confirmed by a gradual increase in SiO2 and K2O contents and a decrease in Mg# and Ni, Co, V, and Cr contents in the sequence from norites to granodiorites and by the facies and phase relationships between the series. Intrusion of rocks took place at shallow depths after low-temperature metamorphism and folding under postcollisional collapse of the East Sarmatian orogen.

Several sections have been studied to understand the distribution and interrelation of basic genetic types of Quaternary deposits in the Uimon basin and adjacent area. The OSL date of 101 ± 10 ka from the glaciolacustrine terrace on the northeastern rim of the basin corresponds to the cool substage of MIS 5. The glaciolacustrine sediments of the northern rim are covered with widespread diamictic flows of the outburst draining of the ice-dammed lake. The diamicts are overlain by a subaerial complex of three loesses and three paleosoils. From the OSL loess dates in the range of 43 to 49 ka we infer that the complex formed from the early MIS 3 through the Holocene. This is also supported by radiocarbon dates from fluvial deposits incised into the glaciolacustrine terrace and into megaflood sediments of the final draining of the last paleolake. The OSL dates in the range of 78 to 89 ka from alluvial sediments indicate that postglacial downcutting of the present-day Katun’ valley probably started just after MIS 5. The discrepancy between the beryllium dates from dropstones and Holocene TL-dates of the Katun’ valley floods ranging from 23 to 6 ka can be explained if the younger floods are related to the draining of moraine- and landslide-dammed rather than ice-dammed lakes. The younger floods, though being less voluminous than the glacial megafloods, were capable to produce giant ripple marks.

High-resolution stratigraphic analysis of the lower second member of the Shahejie Formation of the W79 Block of Bohai Bay Basin, China, has revealed that the study area, previously interpreted as a shallow water delta system, actually originated mainly in a subaerial setting with a distributive pattern. Depositional systems of the distributive fluvial complex (DFC) have been recognized. The regional correlation of the lithofacies within the different depositional systems has led to a high-resolution-stratigraphic framework of two long-term base level cycles, six middle-term base level cycles, and more than 58 short-term base level cycles. Sequence boundary SB1 marks the top of the target interval and is characterized by thick and continuous mudstone overlying sand-rich channel sediments. Sequence boundary SB2 marks the bottom of the target interval and is characterized by stably distributed shales between sand-rich sediments. The base-level fluctuation has a strong tectonic component consistent with the regional tectonic setting; during the active subsidence stage, base-level rising semi-cycles were recorded in the strata, and during the relatively stable stage, base-level falling semi-cycles were recorded.

The pore space of reservoir rocks has a lot of active centers capable to form different types of bonds (from hydrogen to chemical). Therefore, almost any hydrocarbon can be adsorbed to a particular extent on the internal pore surface and form an adsorbed layer, which has a definite spatial configuration and makes contact with a certain part of the rock surface. Study of gas condensate reservoirs brings up the question of the composition of adsorbed hydrocarbons. The properties of such hydrocarbons in many giant gas condensate fields are of special interest as these compounds can serve as an additional source of resources after production of mobile-gas reserves. The performed study of gas condensate reservoirs of the Karachaganak, Astrakhan, and Yamburg fields has shown that their adsorbed hydrocarbons (adsorbed oil) have polar components with sulfur and oxygen atoms.

This study continues the work by Mikhail Gzovsky on geological (tectonophysical) criteria for seismic risk. It is suggested to perform seismic-risk zoning according to parameters of normal and shear stresses on fault planes converted from results of tectonophysical stress reconstructions. The approach requires the knowledge of both dip and strike of the respective fault segments. Slip geometry is estimated from stress tensor, assuming that it is directed along shear stress. The suggested approach is applied to faults in the northern Tien Shan, and the current stress parameters are reconstructed using source mechanisms of catalogued earthquakes recorded by the KNET seismological network of the RAS Science Station in Bishkek. Stress modeling is performed by the method of cataclastic analysis providing constraints on stress ellipsoids, as well as on relations between the spherical and deviatoric components of the stress tensor. Plotted on the Mohr diagram, the fault stress points allow estimating whether the respective fault segments are close to the critical state (brittle failure). The suggested seismic-risk zoning of faults in the northern Tien Shan reveals up to 25 km long hazardous fault segments.

Gas hydrates in sediments can dissociate on heating, which causes a characteristic change in temperature over time. This can be used to detect hydrates and estimate their content. The geothermal method for gas hydrate prospecting consists in obtaining thermograms and defining regularities related to the presence of gas hydrates in the medium. The aim of this study was a quantitative estimation of hydrate content in sediments, based on data from repeated measurements of the temperature of a linear heat source (needle probe). The power of the source is chosen so that hydrate does not decompose in the first measurement but decomposes in the second. Afterward, we solve the optimization inverse problem of determination of the model parameters, one of which is a hydrate content. Experimental data on heating of the laboratory samples are processed, and hydrate contents are obtained with an accuracy of 30%. These values agree with independent estimates. The analytical solution of the axially symmetric problem of gas hydrate dissociation, based on the solution of the Stefan problem, is applied as a mathematical model for hydrate heating and decomposition in the sample.

The article justifies the management system for the Program for Reindustrialization of Novosibirsk Oblast based on accounting for the institutional environment and economic situation in the region. We prove that the success of the program is determined by the possibilities to consolidate the concerned parties' efforts, that is why it is necessary to consider interests, motivation, and trust level of all participants. The obligatory conditions are the clarity and transparency of the program management system and decision-making process. We propose a scheme for managing the program and develop its implementation mechanism. In order to implement the program, it is essential to improve the system of support priorities generation; simplify procedures and ensure maximum availability of local resources for business development; increase the possibility of using state property and public procurement to stimulate demand for the products of Novosibirsk Oblast companies.

The article discusses the performance indicators of Russian regions and their association with population heterogeneity by ethnicity, by country and region of origin. As a theoretical background the research used the neoclassical theory of economic growth and new economic geography. The study assessed the labor productivity, capital productivity and total factor productivity of the regions on the basis of the macroeconomic approach. We employed multidimensional statistical method, economic models of panel data, including the ones with spatial effects. The results of the study show that labor productivity and total factor productivity are positively associated with population heterogeneity by country and region of origin. This effect is stable for the regions with a higher population density. The study also shows that the regions that develop the R&D sphere, increase the human capital and attract migration flows are themselves the sources of total factor productivity growth for the neighboring regions. The acquired results are applicable within regional economic policy.

The article presents the results of monitoring the social feeling of Krasnoyarsk residents. Here we show the unique situation of the year 2014 when, despite growing social tension and anxiety, the level of protest activity started to decrease. We consider the conditions for such social phenomenon and identify the sources of increasing trust in major political and social institutions. We characterize the opportunities for cooperation between the population and authorities. The level of conformist attitudes has risen dramatically. The article points out that this «socialpeace» will not last long; the population will adopt other social relations unless there are new strategies for regional development.

Using the example of Yamal-Nenets Autonomous Okrug, the article analyzes the socio-economic aspects of human ecology problems in the circumpolar area basing on the data on environmental issues and ecology-related diseases, as well as peoples' subjective views about their environmental vulnerability. The level of peoples' susceptibility to the objective ecological conditions in YaNAO, as recorded in contrast to the subjective feelings of insecurity from environmental threats, is one of the key parameters of social well-being for residents in this region. We conclude that local residents in the study sample hardly sense any environmental threats compared to the sample of the Russian population in general, and its continuous decline against an increase in actual environmental risks and public health threats associated with an unfavorable environmental setting. An inconsistency between subjective perceptions of environmental threats and the objective growth of environmental threat is defined as a significant social and psychological factor of environmental risk. We practically demonstrate how to increase social and psychosocial environmental awareness.

The article suggests an approach to measuring and evaluating the factor of innovation on macro- and regional levels without common innovation indicators. Innovation activity is seen as a force that can slow down or even overcome the objective increasing in per-unit investment when shifting to a higher technological level of production. We assess the influence of the innovative factor solely in connection with the ratio between investment efforts and the resulting indicators of economic dynamics, growth in labor productivity. Using a particular method of evaluation, we give the assessments of innovation intensity in investment relating to the Russian regions in 2005-2007 and 2008-2013. The article demonstrates significant differences between the line-up of leading regions in some publications. It turns out that the important characteristics of economic development for leading regions identified with the proposed method are much more preferable than those of «innovative» leaders determined with traditional rank-rating approaches. Concerning the Siberian regions, we notice a major polarization of innovation intensity indicators. In fact, no region has moderate innovation indicators.

The article shows that this large-scale project, which includes constructing the Power of Siberia cross-country gas pipeline, developing Siberian gas fields, building a gas processing plant and a helium plant complex, will promote the economic development of Eastern Siberia and the Far East and improve their investment attractiveness. An important social result of the Power of Siberia project will be increased employment rates at factories producing equipment and components for the gas industry, in construction sector companies, and others. The Power of Siberia pipeline route was chosen in such a manner that it will gasify the maximum possible number of populated localities. Gasification of households and enterprises in regions will improve the quality of life and the environment, allow organizing a series of new high-performance plants and industries, and enhance the competitiveness of their products.

The article presents the results of researching the impact of the Power of Siberia gas pipeline on the economic development of the surrounding areas in Irkutsk Oblast. The involvement of the Kovykta gas and condensate field in the construction of the cross-border gas pipeline will have no significant effect on the socio-economic development of Irkutsk Oblast. Gasification of settlements is only possible in the area of gas production, the project does not generate any new elements of infrastructure, and the growth of budget revenues is reduced by federal exemptions. An alternative to the corporative approach is to enhance the project by adding a regional gas supply pipeline to the south-eastern part of the region, which will give impetus to the development of gas processing methods with new technology as a part of the existing petrochemical complex and the overall gasification-based restructuring of the industry.

The article describes the process of finding the answer to the question of what qualities a good municipal strategy of socio-economic development should have. Our research tool was the analysis of the results and proceedings of the urban strategies competition in 2014, which covered Russian cities with a population of over 100,000 people. We examined the properties differentiating the strategies of cities, as well as systematized the direct statements of jury members and mayors of finalist cities given on the qualities of good strategies. We have reached the following consensus: a good municipal strategy should be ambitious (aimed at high results), equipped with elaborate implementation and monitoring mechanisms, and concentrating efforts on priority flagship projects; it should be developed under the leadership of its mayor together with key players in urban development, understood and accepted by the local community.

A variety of perspectives on contributions made by small, medium-sized and large enterprises to the innovative development of Russia and approaches to researching this problem indicate that this topic remains open for discussion. The article shows the reasons why small and medium-sized companies make a minor contribution to the innovative development. Basing on a survey among executives in Novosibirsk Oblast, we have found out that the majority of enterprises follow a conservative behavior model. Under new economic conditions, their innovation goals are still related to updating and expanding their production capacities. Research and development as a basis for developing fundamentally new competitive products is declared to be a priority only in a few companies surveyed. Among the wide range of state support measures for entrepreneurship aimed at easing institutional and structural barriers, the most important ones for small and medium-sized companies are financial instruments. The need to help develop cooperation ties and networking is not yet recognized as a priority.

The article provides a rationale for the growth opportunities of Kazakhstan's manufacturing sector in the structure of industrial production and output of high-value-added products. This development trend will lead to a balanced use of hydrocarbon resources, which will determine specific demands for feedstock by oil refineries and petrochemical facilities, and export volume. Solving the problem of balancing the volumes of production, export, and processing of hydrocarbon raw materials, while taking into account its qualitative parameters, will play a positive role in changing the industrial structure towards increasing the share of the manufacturing sector.

The article discusses the problems and possibilities of cluster formation as exemplified by international experiences in stimulating the innovation environment in the economy. Basing on the comparative characteristics of Bulgarian and European regional policies after 2006, we analyze the essence of the cluster approach in Bulgaria within European policies, aimed at supporting the development of clusters. An emphasis is put on the priorities identified in the National Development Strategy of Bulgaria for the periods 2005-2015 and 2012-2022. Particular attention is paid to the state's and local authorities' roles in the formation and implementation of cluster policy. We systemize services provided through indirect non-financial instruments to support cluster development in the EU and cluster initiatives in Bulgaria. We demonstrate positive experience in implementing the cluster approach in Bulgaria by considering a specific region, namely Sevlievo Municipality.

The article describes the reasons for low educational attainment levels among Indigenous peoples in Canada as compared to the non-Indigenous population. We examined intra-Indigenous trends in educational attainment and compared attainment levels between Indigenous and non-Indigenouspopulations in Canada across high school and post-secondary education (PSE). Indigenouspeoples' educational attainment in Canada is improving: post-secondary attainment increased by 86 percent between 1996 and 2011. This tendency is observed for Metis, off reserve, and non-Status Indians. We justify regional policies aimed at developing the emerging trends for Indigenous peoples' education in Canada.

The data obtained in 1995-2014 in the areas of the Sulakskaya and Turalinskaya lagoons (Dagestan, the western coast of the Middle Caspian) were summarized. The lagoons are located in a “bottleneck”, a narrow migration corridor traversed by one of the largest migration routes of trans-Palearctic species in Russia. This route is a part of the West Siberian-East African migration range. The migration traffic and territorial localization of the Laridae populations, participating in the total migratory flow along the western coast of the Caspian Sea were determined. The present-day migratory range of Laridae covering the area from Western Europe to Lake Baikal and Western India was specified. It was determined that Dagestan is crossed not by one but two independent and stable migration flows of Laridae, flying across the transit region in different migration routes but at the same periods of time. Three types of migration intensity of Laridae across the study area were defined: weak, average and mass migration. Both spring and autumn migration includes 5 peaks of migration activity (migratory waves). Timing, taxonomical composition and abundance of Laridae species vary for each degree type of migratory waves. Key determinants of migratory wave intensities are abundance of migratory populations and weather conditions of the year. It was proved that over the last 5-7 years there has been a steady decrease in abundance of some Laridae species on the western coast of the Middle Caspian. This decrease was determined by a set of factors acting across the whole migration range. Decrease in abundance of migratory Laridae leads to blurring of the boundaries between migratory waves and migration intensity. It causes changes in migration routes of some Laridae populations which now have shifted from traditional wintering grounds along the western coast of the Caspian Sea and countries of the Middle East and North-East Africa to India.

The paper presents the radial distributions of the pressure measured with a Pitot tube for the case of a radial jet with/without swirling of the input flow in the pre-chamber; the length of the supersonic part of the jet, dependency of the jet thickness as a function of the distance from the nozzle outlet, and approximating analytical formula for the jet thickness that generalizes the experimental data. Experimental data demon-strated that at the deposition distances lower than 4–6 gauges from the nozzle outlet, the solid particle velocity and temperature are almost uniform over the jet cross sec-tion. This means that the target surface can be allocated here without loss in coating quality and deposition coefficient. The maximal recommended distance where the deposition is still possible is the length of l_s0 ~ 16 gauges

The possible influence of fastening the models on a side pylon at their tests in wind tunnels on their aerodynamics at supersonic flow speeds has been considered. The physical problem of the pylon and the model interference has been investigated, and the estimates of the pylon influence on integral aerodynamic characteristics have been obtained. The numerical computations of the flow have been done using the averaged Navier-Stokes equations and the SST k-ω turbulence model in the range of freestream Mach numbers М = 2.5–5. As the investigation object the “classical” body of revolution of large aspect ratio is considered, which has a cruciform forward fins and six-blade tail stabilizers.

This piece of work is concerned with the application of two conventional measuring probes, pressure probe and hot wire, in the wall layer of subsonic ducted, pipe and channel, flows for velocity measurements. Careful measure­ments have been carried out and analysed accordingly for Reynolds number range of 2.8x10⁵≤Re_m≤4.5x10⁵ and 4x10⁴≤Re_m≤2.3x10⁵ for the pipe and the channel, respectively. Pressure probes of outer diameters (d₀⁺= d₀xu_r /ν) 20-120 wall units and hot wire, having wire length (l⁺= l u_τ /ν) of 50-250  for the current Reynolds range, have been utilized to carry out the present measurements. When the pressure probe was applied in the wall layer, the wall proximity and the shear gradient played major roles of its incorrect velocity readings, however, this effect was far from being influencing the hot-wire velocity measured in the overlap region. When the pressure probe results compared to those obtained by the hot wire, the pressure probe's data showed hump in the normalized mean velocity profiles around the wall distances y⁺≤300 and y⁺≤150 for the pipe and the channel, respectively. Available corrections are adopted and applied to the pressure probe data measured, yielding results that are comparable to those of the hot wire and this was also demonstrated by comparing the present results corrected to the so-called the logarithmic velocity profile.

Specific features of shock wave interaction in a viscous heat-conducting gas with a low ratio of specific heats are numerically studied. The case of the Mach reflection of shock waves with a negative angle of the reflected wave with respect to the free-stream velocity vector is considered, and the influence of viscosity on the flow structure is analyzed. Various issues of nonuniqueness of the shock wave configuration for different Reynolds numbers are discussed. Depending on the initial conditions and Reynolds numbers, two different shock wave configurations may exist: regular configuration interacting with an expansion fan and Mach configuration. In the dual solution domain, a possibility of the transition from regular to the Mach reflection of shock waves is considered.

We present the results of numerical investigations of the parameters of postdetonation waves forming at a passage from the zone occupied with a bubbly liquid formed by the detonation wave to a zone filled with a liquid without bubbles. The dependence of the pressure amplitude of detonation waves and postdetonation waves on the gas volumetric content of bubbles has been studied. A possibility of the detonation transfer through the layer of a bubble-free liquid separating the regions of the bubbly liquid has been shown, the map of possible situations at the detonation transfer through the layer of this liquid has been presented.

The results of experimental investigations of local hydrodynamics of a coolant flow in fuel rod assembly (FA) of KLT-40C reactor behind a plate spacer grid have been presented. The investigations were carried out on an aero-dynamic rig using the gas-phase diffusive tracer test. An analysis of spatial distribution of absolute flow velocity projections and distribution of tracer concentration allowed specifying a coolant flow pattern behind the plate spacer grid of the FA. On the basis of obtained experimental data the recommendations were provided to specify procedures for determining the coolant flow rates for the programs of cell-wise calculation of a core zone of KLT-40C reactor. Investigation results were accepted for the practical use in JSC “OKBM Afrikantov” to assess heat engineering reliability of cores of KLT-40C reactor and were included in a database for verification of CFD programs (CFD-codes).

The results of experimental studies on the structure of the temperature field in the tube cross section at the flow of liquid-metal coolant in a T-shaped mixer are presented. Experiments were carried out using the Rose alloy as the working fluid. To determine temperature distribution on the test section wall, infrared thermography was used; to determine temperature distribution in the channel cross section, a mobile thermocouple was used. Considerable temperature maldistribution in the mixing zone of liquid flows with different temperatures on the tube wall and in the coolant melt is shown.

The unsteady stagnation point flow impinging obliquely on a flat plate in presence of a uniform applied magnetic field due to an oscillating stream has been studied. The governing partial differential equations are transformed into dimensionless form and the stream function is expressed in terms of Hiemenz and tangential components. The dimensionless partial differential equations are solved numerically by using well-known implicit finite difference scheme named as Keller-box method. The obtained results are compared with those available in the literature. It is observed that the results are in excellent agreement with the previous studies. The effects of pertinent parameters involved in the problem namely magnetic parameter, Prandtl number and impinging angle on flow and heat transfer characteristics are illustrated through graphs. It is observed that the influence of magnetic field strength increases the fluid velocity and by the increase of obliqueness parameter, the skin friction increases.

The mathematical modeling of the conjugate heat transfer in a closed rectangular region has been carried out under the conditions of the radiation supply of energy. The temperature and stream function fields obtained by the modeling illustrate a substantially unsteady nature of the conjugate heat exchange process under study. An analysis of temperature distributions in typical cross sections of the solution domain has shown a considerable inhomogeneity of the temperature field. It is found that an increase in the Rayleigh number leads to substantial modifications of the temperature and stream function fields. The influence of the distribution of radiation fluxes over the internal interfaces on the temperature fields and the airflow character is shown. The influence of the turbulization on the heat transfer intensity near the interfaces between media has been estimated. Comparisons of the obtained numerical results with experimental data have shown their good agreement

In this paper, we investigated numerically an unsteady boundary layer flow of a nanofluid over a stretching sheet in the presence of thermal radiation with variable fluid properties. Using a set of suitable similarity transformations, the governing partial differential equations are reduced into a set of nonlinear ordinary differential equations. System of the nonlinear ordinary differential equations are then solved by the Keller-box method. The physical parameters taken into consideration for the present study are: Prandtl number Pr, Lewis number Le, Brownian motion parameter N_b, thermophoresis parameter N_t, radiation parameter N_r, unsteady parameter M. In addition to these parameters, two more new parameters namely variable thermophoretic diffusion coefficient parameter ε and variable Brownian motion diffusion coefficient parameter β have been introduced in the present study. Effects of these parameters on temperature, volume fraction of the nanoparticles, surface heat and mass transfer rates are presented graphically and discussed briefly. To validate our method, we have compared the present results with some previously reported results in the literature. The results are found to be in a very good agreement.

Heat transfer at rivulet water flow over the constantan foil with the length of 80 mm, width of 35 mm, and thickness of 25 mm was studied experimentally. The foil surface temperature was measured by an IR-scanner. Distributions of heat flux density on the surface of the foil, where the liquid flowed, were obtained. To determine the heat flux density from the foil to liquid near the contact line, the Cauchy problem was solved for the stationary heat equation using the thermographic data. Calculation results showed that the maximal heat flux occurs in the area of the contact line and exceeds the average heat flux from the entire foil surface by several times. This is explained by the influx of heat from the periphery of foil to the rivulet due to the relatively high value of heat conductivity coefficient of the foil material and high evaporation rate in the region of the contact line.

The mixing model was used for analysis of linear kinetic problems of phase tran-sition. The asymmetry of evaporation and condensation, which occurs for intensive processes, remains even for the case of linear approximation. The analytical solution for kinetic jumps of pressure and temperature at the condensed phase surface was obtained: it complies with the results of the classical linear theory. The key result of this study is analytical solution for dependency of pressure jump (condensation) on the temperature factor. This dependence has a minimum near the margin between the abnormal and normal regimes of condensation.

In the present work, the entropy generation due to the heat transfer and fluid friction irreversibility is investigated numerically for a three-dimensional flow induced by rotat-ing and stretching motion of a cylinder. The isothermal boundary conditions are taken into account for the heat transfer analysis. The similarity transformations are utilized to convert the governing partial differential equations to ordinary differential eq-uations. Resulting nonlinear differential equations are solved using a numerical scheme. Expressions for the entropy generation number, the Nusselt number and the Bejan number are obtained and discussed through graphs for various physical parameters. An analysis has been made to compare the heat transfer irreversibility with fluid friction irreversibility using the expression of the Bejan number. It is found that the surface is a durable source of irreversibility and the curvature of cylinder is to enhance the fluid friction irreversibility.

An extensive study was performed to establish correlations between the crystal structure, the grain composition, and the dielectric and thermophysical properties of high-temperature multiferroics of the Bi_1-x Dy_x FeO₃ type (x = 0.05–0.20). It is shown that a trade-off between the macroresponses in the materials is achieved at x = 0.10; this circumstance permits recommendation of the materials for practical use.

Theoretical estimations are made in order to support the possibility of the non-equilibrium carbothermic reduction of magnesium after the plasma treatment of agglomerated particles-decamicron mechano-composites which consist of uniformly mixed reacting nano- and sub-micron insertions of magnesium oxide and soot with the preset stoichiometric composition. Experimental results are presented to confirm the practical attainability of the process.

A three-dimensional problem on the control of furnace temperature during cooling of ceramic products of arbitrary shape with allowance for the constraints on thermal stresses is analyzed. An algorithm for calculating a temperature regime making it possible to avoid the occurrence of fracture and irreversible deformation in the products being cooled is proposed. With the example of cooling of a ceramic holder for a spiral wire, a computational experiment is performed. A temperature regime in which the cooling of the product accomplishes in a certain time without exceeding the admissible values of thermal stresses is identified.

In this paper, the process of convective heat exchange between the cooling air and the cylindrical solid is experimentally studied in a chamber furnace at double-sided cross-flow around the solid, and the corresponding criterial equation is obtained.