Home – Home – Jornals – Thermophysics and Aeromechanics 2006 number 3

We suggest a model of elastic rebound for the M = 7.3-7.5 Chuya earthquake of 27 September 2003 based on 3D deformation data from the Gorny Altai. We report processed data from yearly resurveyed Altai GPS stations through 2000-2004. The geodynamic network of the Institute of Geophysics (Novosibirsk) consists of 21 stations, including the Klyuchi reference station (world network code IGS-NVSK DOMES N12319 M001); it covers the structural elements of Gorny Altai and extends into the southern West Siberian plate and the West Sayan mountains. Displacement of the NVSK station in the system of permanent stations of Asia and displacement of Central Asian stations were processed to obtain a map of GPS velocities for the Gorny Altai. The velocities are in a range from 0.2 to 11 mm/yr. The velocity field shows signature of a preseismic process before the Chuya event in the southern Gorny Altai. Measurements through 2003-2004 give a pattern of postseismic deformation indicating a right-lateral strike slip in the epicentral area. The amount of displacement decreases away from the nodal plane from 300 mm at 15 km to 25 mm at 90 km far from the main shock. This regularity is explained in terms of elastic rebound in a 2D dislocation model. Modeling with the use of experimental data showed a 4MPa stress release and a 2 m displacement along the fault in the epicenter, at an average fault depth of 8 km. The shear strain related to the earthquake was estimated to be 10^-6 within 100 km away from the rupture.

We report locally nonlinear approximation algorithms for processing high-frequency induction logging data in axisymmetrical models. Forward problems for high-frequency logging are solved using the Born and Rytov approximations. Space conductivity variations in the high-frequency range change only the phase components of the electric or magnetic fields. The Rytov locally nonlinear approximation is the most accurate (1-2% error). Numerical modeling and comparison of high-frequency induction logging diagrams are applied to typical 2D models of terrigenous reservoirs.

Based on microprobe data on the contents and distribution of Cl and F in halogen-containing minerals of enclosing intrusive rocks and their hydrothermally altered varieties, the role of metasomatic processes in the balance of volatiles of the ore-forming system is discussed by the example of porphyry Cu-Mo deposits of Siberia and Mongolia. Two groups of deposits are considered: essentially copper (Erdenetiyn-Ovoo, northern Mongolia, and Aksug, Tuva), with prevailing propylitization and quartz-sericite alteration, and essentially molybdenum (Sora, Kuznetsk Alatau), with prevailing K-metasomatism (orthoclase-biotite association). All types of hydrothermal transformations lead to a drastic decrease in Cl contents in metasomatic minerals as compared with halogen-containing magmatic minerals. In chlorites and sericites, which are the most widespread in metasomatites of essentially copper deposits, no Cl and Cl-containing minerals were detected by microprobe analysis, whereas F was found in large amounts in some metasomatic minerals: secondary biotite, actinolite, chlorite, and sericite. At the studied deposits, huge volumes of enclosing rocks (hundreds of mln tons) are involved in metasomatism. The large amounts of thus released halogens (particularly Cl) might have seriously influenced the regime of volatiles during the ore formation, including the increase in the salinity of hydrothermal solutions.

First data on the U-Pb age of island-arc gabbroids and granitoids of the Dzhida Caledonide zone are presented. It has been established that these rocks formed at nearly the same time (506 ± 1 Ma, gabbroids, and 504 ± 2 Ma, granitoids) at the final stage of the evolution of ensimatic island arc. The low ⁸⁷Sr/⁸⁶Sr (0.7031-0.7033) and high positive ε _Nd (T) (+6.7...+7.6) values and localization of sample points at the same isochron evidence that the studied igneous rocks belong to the same differentiated gabbro-diorite-tonalite series, which resulted from the melting of a primary depleted mantle source with the subordinate role of a long-lived crustal component.

By the example of West Siberia, it has been shown that paleocarpology permits quite a detailed division of the continental Cenozoic of closed territories, which is unattainable by other paleontological methods. In the range from Aquitanian to Gelasian, ten biostratigraphic zones have been recognized, whose sum covers the complete stratigraphic interval of the section.

Palynological studies were given to the Holocene lacustrine-palustrine sediments of Lake Beloe (Novosibirsk Region). On the basis of cores obtained from two boreholes, spore-and-pollen diagrams were compiled and four palynozones were recognized to characterize the vegetation for the last 5000 years. It has been established that the lake has been surrounded by birch forests for this period. The pollen of Pinus sylvestris L. is a component brought from other zones and reflects a remote flora. The local vegetation was subject to changes. In the early sub-Boreal period the climate was wet and somewhat warmer than it is now. Diverse hydrophytes, sedge, and reed were quite abundant around and within the water body. In the second half of the sub-Boreal period, the lake was surrounded by swamped areas, where ferns, horsetails, and palustrine Thelipteris grew. Sapropels began to form at around the onset of the sub-Atlantic period. The dwarf birch dispersed on the shores of the lake. The amount and diversity of hydrophytes were drastically diminished. Most likely, some cooling took place. Since the second half of the sub-Atlantic period, the vegetation of Lake Beloe has acquired the modern character. The lake is surrounded with reeds, canes, and sedge communities. Pondweed, duckweed, Myriophyllum, and other aquatic plants grow in the water body.

We briefly report the history of studying Baikal gas hydrates, their discovery in the areas of new structures, and the specific composition of Baikal hydrate-containing subsurface sediments. The structures with a volcanic breccia were referred to as mud volcanoes. The first geological search criteria for the presence of gas hydrates in the Baikal subsurface sediments are presented.

Detailed geochemical studies of buried andesites, supposedly of Permo-Triassic age, from the West Siberian Plate have revealed their specific features. The andesites differ drastically in petro- and geochemical compositions from similar rocks of active continental margins and island arcs and are very similar in geochemistry to continental latites. These data do not contradict the model of andesite formation through crystallization differentiation of subalkalic basaltic melt.

The high gold potential of Cu-ore (Cu-skarn, porphyry Cu-Mo, and pyrite-polymetallic) deposits widespread in the Altai-Sayan folded area is shown. The ore formation processes at these deposits included multistage mineralization with the gradually decreasing temperature of ore-forming solutions. At the early high-temperature stages, mainly the profile ores (often, of zonal structure) of the deposits were produced. Their mineral composition is closely related to the composition of the corresponding ore-magmatic system and is regularly repeated in ore objects of different sizes and ages. At the final stages, low-temperature mineral assemblages formed, which often have a similar set of ore and vein minerals. A distinctive feature of these assemblages is the presence of Ag, Pb, and Au tellurides, Bi minerals, native bismuth, and Hg-containing minerals. Gold in the minerals is of varying fineness; the main trace elements in it are Ag and Hg. The low-temperature mineral assemblages are close to ores of epithermal deposits (including Carlin-type ones) developed in the same areas. These ores might be the products of the final-stage evolution of the ore-magmatic systems.

In this paper we consider products of natural pyrolysis of lignite, which resulted from the high-temperature spontaneous combustion of spoil heaps of the Chelyabinsk coal basin. These products were studied by pyrolysis, element and petrographic analyses, chromato-mass spectrometry, and X-ray diffraction method. We have established that under reducing conditions, the degree of pyrogenic coal transformation and the composition of pyrolysis products vary greatly, from graphite-like phases to bitumens, and depend on the temperature and degree of the system openness.

Analysis of a sample of 18 relatively well-explored sedimentary basins of North America shows that the distribution of oil fields with regard to amount of resources depend on the characteristics of the sedimentary filling of the basins. In rather young and intensely sagged basins, which abound in objects with high rates of accumulation, the deviations from the truncated Pareto distribution can be quite significant. The revealed dependences permit the parameters of size distribution of oil accumulations to be estimated at the very beginning of study of basins, without sufficient information on sizes of largest fields. The obtained empirical regularities qualitatively agree with results of analysis of the available simplest theoretical model for size distribution of hydrocarbon accumulations in petroliferous systems.

We investigated signature of Middle Pleistocene soft sediment deformation in lacustrine deposits of the Kok-Moinok basin (a bay of Lake Issyk-Kul', western Issyk-Kul' region) and its implications for past seismicity. Convolute structures are exposed in interfingering shallow lacustrine, beach and fluvial sediments. Other deformational structures we encountered exist as marl intrusions in coarse pebbly sand whereby the latter progresses upward making a sort of pillars. We used seven field criteria for relating soft sediment deformation to paleoseismic triggering which provide strong evidence for the seismic origin of the structures: (1) proximity to active seismic zones; (2) potentially liquefiable composition of sediments which are soft metastable sand and low-cohesion clay; (3) similarity to structures formed experimentally and those produced by natural seismic shaking; (4) absence of detectable effects of slope instability (gravity sliding); (5) stratigraphic position of deformation units between undeformed sediments; (6) lateral extent and regional abundance of deformational structures correlated over large areas; (7) cyclic repetition of structures in the section. We infer from empirical relationships between earthquake magnitude and the maximum epicentral distance to liquefaction sites that deformation was most likely associated with events in the highly seismic active epicentral zone north of Lake Issyk-Kul'. The earthquake-induced deformational structures record high seismic activity already in the Middle Pleistocene.

MTS data from five profiles across the zone of the Talas-Fergana Fault (TFF), interpreted in geoelectrical models, reveal a 10-15 km thick crustal conductor (consisting of several conductors) traceable to a depth of 45 km. The conductor rises to the upper crust along TFF and flattens out towards the Southwestern and Northeastern Tien Shan. The anomaly attributed to the TFF zone is divided into the Talas, Central, and Southern segments in the map view. TFF, interpreted as a high-angle strike-slip fault from geological data, is recorded in the electromagnetic field as a nearly vertical conductor only in its Central segment and shows a listric geometry in the Talas segment.
Interpretation of the MTS results correlated to geological data suggests that the modern geodynamic framework of the southwestern Tien Shan includes a structure of an arcuate plan view and a listric geometry which deepens to 40-45 km toward the center of the Fergana block. This pattern of the active zone agrees well with structural, paleomagnetic, and GPS data on the rotation of the Fergana block under the effect of pressure from the Pamirs.

Studies of deposition processes in Bay Proval on the eastern side of Lake Baikal allow us to approach reconstruction of natural and man-caused events through the past 150 years on the basis of reliable sedimentological tracers. The tracers include fossil soil (1862), chlorinated organic compounds (since the 1950s), ¹³⁷Cs (since 1953), and modern soil (1959). The project for investigation of recent sedimentation in the region around the Selenga delta offers an opportunity to decipher the unique natural microchronicle of natural and man-caused events in the Late Holocene.

The features of bearing were considered for 14 species of annual decorative plants of Asteraceae family introduced in the forest-steppe region of West Siberia and belonging to different ecological-biological groups. Laboratory germination and germinating capacity of seeds were investigated for different storage time; the dynamics of germination was also studied. The potential and actual seed productivity of inflorescences on the sprouts of different embranchment orders were determined for four model species (Dimorphotheca pluvialis, Brachycome iberidifolia, Sanvitalia procumbens, Tagetes patula). The productivity coefficients were calculated for each species per one plant and per a sprout of the corresponding order.

It was established in the investigation of changes in the fertile bodies of mushrooms in East Kazakhstan (the Republic of Kazakhstan) that the scyaride fauna occurring at different stages of the life cycle of mushroom fertile bodies accounts for 20 species belonging to 10 geni. Dominant species are those of Bradysia genus (6 species) and Corynoptera genus (4 species); Lycoriella genus is represented by three species. Pnyxia, Scatopsciara, Cratyna, Ostroverchovana, Phytosciara, Camptochaeta and Epidapus geni are represented by one species each.

Results of an experimental study of aerodynamic characteristics of models of two hypersonic re-entry vehicles (ARES-H aerospace demonstrator proposed by EADS-ST and EXPERT re-entry capsule proposed by ESA ESTEC) are presented. The experiments were performed in a new wind tunnel AT-303 at ITAM SB RAS in the range of free-stream Mach numbers

Characteristics of the fields of mean density and density fluctuations measured with introduction of periodic disturbances into a hypersonic viscous boundary layer on a flat plate are presented. The experiments are performed for a flow Mach number M_∞ = 21, Reynolds number per meter Re_1∞ = 6·10⁵ m^-1, and temperature factor of the surface T_w /T₀ = 0.26. The disturbances are introduced into the shock layer by an oblique gas-dynamic whistle.

Results of an experimental hydrodynamic and heat-transfer study of the turbulent separated flow developing over a system of several cross-flow ribs are reported. Conditions with low and high free-stream turbulence are considered. Visualization and heat-transfer data are presented, and a comparison for two turbulence levels is given. In the system of three or more ribs, a very unstable flow in the second inter-rib cell was observed under low-turbulence conditions. Under a high level of free-stream turbulence, the flow in the first inter-rib cell is unstable; this observation is supported by measured pressure distributions. Addition of each next rib makes the separation flow region behind the last rib and the pressure recovery region less extended, and decreases the coordinate at which the rate of heat transfer attains its maximum. In the high-turbulent flow, the heat-transfer intensification in the second inter-rib cell amounts to 30 %.

The effect of periodic blowing/suction on characteristics of a turbulent boundary layer formed on an axisymmetric body of revolution in a nominally gradientless incompressible flow is studied experimentally. The Reynolds number based on the momentum thickness at the location of an annular slot for blowing/suction is 1176. The dimensionless slot width in the wall units is 68. It is demonstrated that blowing/suction aimed at controlling the boundary-layer flow is a fairly effective method for controlling the near-wall turbulence structure and ensures a certain gain in friction drag over the initial configuration (the maximum gain reaches 25 30 %).

An ejector scheme intended for forming supersonic heterogeneous flows is experimentally examined as applied to conditions typical of cold gas-dynamic spraying. Pressure and temperature distributions in the supersonic part of the nozzle are reported, and critical operating regimes of the nozzle are identified. Specific features and advantages demonstrated by this scheme in practical applications are considered. Results of preliminary tests on the application of coatings with the use of the nozzle unit under study are presented.

A computational model for processes in the duct of an experimental setup consisting of a shock tube and an MHD duct is presented. The one-dimensional model is used for determining the flow characteristics in the entire setup duct, and the three-dimensional model is used for studying the current layer dynamics in the MHD channel. Computations have enabled the elucidation of flow structure and of the peculiarities of current layer formation.

This paper deals with wall shear stress in an upward gas-liquid slug flow inside a vertical tube. Local characteristics were measured by the electrodiffusion method. The method of conditional averaging over realization ensemble was used, and this allows distinguishing large-scale structures on the background of turbulent pulsation of liquid. While averaging, each slug velocity measured by a double probe of electric conductivity was taken into account. Averaged distributions of shear stress over the wall under a gas slug were obtained for different mode parameters.

Two different mechanisms responsible for the were revealed impact of gas bubbl injected into a boundary layer on the shear stress on the wetted surfaces. Both mechanisms exist due to extremely high sensitivity of bubbles even to very low pressure gradients and due to a high value of the virtual mass and coefficient of viscous drag for bubbles. The first mechanism manifests itself at the interaction of vortex structures with bubbles in the near-wall layer y⁺ < 250. The second mechanism is due to pressure gradient along the wetted surface. Ascertainment of these mechanisms explains the known discrepancies in the experimental results on gas saturation obtained on different experimental setups.

Mathematical modelling of three-dimensional steady free convective incompressible viscous gas flows in the rooms with a heat source is carried out within the framework of the Navier Stokes equations with the effective viscosity determined on the basis of the κ-ε turbulence model. The investigation is carried out for the case of model rooms and heat sources having the form of rectangular parallelepipeds with square bases. The influence of the heat source power and the sizes of the room base on local and averaged values of the air velocity and temperature in the rooms is analysed. The flow pattern in the room is shown to have a torus-like shape. It is found that the variation of sizes of the room base rather than the capacity variation of the heat source is of determining importance for the gas motion character in a closed volume.

Experimental results on reversing non-stationary heat transfer are presented for filtration of an air flow through an immobile heat accumulating medium consisting of lead (D = 2.0, 3.5, and 4.5 mm) and glass (D = 3.2 mm) balls. The studied device imitated the cyclic modes of heat regeneration in the ventilation system for domestic and office rooms. Dependency between the time of flow switching and Re number was measured. The mathematical model describing heat transfer between a gas flow and an immobile layer of balls was developed. Good correspondence between the experimental data and calculation results is observed for high Reynolds numbers. For low Re numbers the effect of heat losses is considerable, and experimental time of flow switching is shorter than the calculation one.

The saturation pressure, pressure and density of superheated vapor of 1,1,1,2,3,3-hexafluoropropane (HFC-236ea, R-236ea) were studied by an isochoric piezometer within the temperature range of 294-423 K up to the pressure of 4.0 MPa. The uncertainties of temperature, pressure, and density measurements were estimated as ±20 mK,  ±1.5 kPa,  ± (0.1-0.2) %, and  ± (0.1-0.2) %, correspondingly. The purity of studied samples was 99.68 mass %. The obtained experimental data are shown as tables and analytical equations. Coefficients of the virial state equation were calculated for R-236ea on the basis of these data.

A two-dimensional mathematical model has been developed for unsteady thermophysical processes in the industrial duct of an uranium-graphite reactor with conversion fuel elements of the bush type. The numerical algorithm and computer code have been developed on the basis of the proposed model to investigate the temperature fields in an aluminum core, fuel, shell as well as in the cooling water with regard for the design and technological assembly peculiarities. The results of some computational experiments are presented, which characterize the distribution of temperature fields in the column of fuel elements and in the cooling water.

Methods of synthesis of fluorine-containing dialkyl and fatty-aromatic ethers involving the reactions of aliphatic alcohols and phenols, including aromatic ones, with perfluoroolefins are considered. To obtain various fluorine-containing polyethers, polyhydric alcohols were used in reactions with perfluorinated tri-, tetrafluoroethylene and hexafluoropropylene. Some properties of fluorine-containing ethers are discussed; examples are their application are presented.

Results of the galvanochemical oxidation (GCO) of 2-chlorophenol (2-CP) in aqueous solutions at pHin 3 are discussed. A more substantial decrease in the concentration of 2-CP (C2-CP = 1.55 10

Ultradispersed oxyhydroxides of aluminium have been obtained upon the interaction of electroexplosive nanodispersed aluminium with water at 55 oC. Initial samples were subjected to ageing under the alkaline condition (pH 10) at 20 and 50 oC. It has been demonstrated that the content of structural water in resultants of the reaction increases during the course of ageing; the specific surface and the limiting adsorption volume decrease. An increase in the intensity of reflexes of bayerite and a decrease in the intensity of pseudoboehmite lines with time have been noted. The sorption of saturated benzene vapour at 20 oC drops during the ageing of samples. The observed processes occur more intensively at 50 oC. An inference about the transformation pseudoboehmite

Processes that occur during mechanochemical activation of the mixtures of diopside with calcite and amorphous silicon dioxide with calcite in a centrifugal planetary mill are investigated. According to the data of IR spectroscopy and XPA, with calcite content up to ~10 mass %, mechanochemical interaction of the mixture components results in the formation of a substance which is similar to carbonate-containing silicate glass. During mechanochemical activation of a mixture of amorphous silicon dioxide with calcite (at a molar ratio of 1 : 1) the degree of interaction between the components decreases substantially, the major part of input mechanical energy is consumed for the achievement of mechanochemical equilibrium between calcite and aragonite. Investigated processes were compared with the previously discovered mechanically induced absorption of carbon dioxide by calcium- and magnesium-containing silicates. The data on phase formation under heating of mechanochemically activated mixtures of silica with calcite are reported.

Reasons for phase change in zirconia upon its intensive mechanical treatment in mills have been discussed. It has been demonstrated that when used steel balls and barrels, oxidation of wear products and their mechanochemical interaction with ZrO2 occurs along with a decrease in the size of particles and crystallites. It has been found that implantation of cations of an extrinsic metal in the crystal lattice is favourable to the stabilization of a more symmetric modification and to an increase in the critical size of crystallites, above which the monoclinic modification becomes stable. A conclusion has been made that an increase in the contribution of superficial energy to the Gibbs energy plays dominating part in the phase change on initial stages of mechanical treatment, while the thermodynamic stability in the further process is controlled preferentially by a stabilising impact of impurity cations. Under conditions that prevent from pollution of ZrO2 by metal, a dynamic equilibrium is established between the forward change to tetragonal modification and the reverse, to monoclinic.

The concentration dependence of the first moments M1 of fluorescence spectra of the fractions of humic acids (HA) differing in molecular masses in aqueous solutions within the concentration range 0.5

The mechanism of processes involved in the interaction of humic acids with heavy metal ions, as well as the features of structure and properties of metal humic complexes (MHC) are investigated with the help of EPR spectroscopy and TGA. The topography of distribution of functional groups on the surface of the powders of humic acids and MHC is investigated by means of adsorption of acid-base indicators. The stability of MHC in aqueous medium and the mobility of heavy metals are studied with the help of HCl leaching method.

The reactions of FeCl2, CoCl2, NiCl2 with MBH4 (M = Li, K, Na) proceeding during mechanical activation of the mixtures of crystal substances in a vacuum vibratory mill were investigated. It was established that the reactions are accompanied by the formation of diborane(6), or B2H6, the yield of which depends on the nature of initial reagents, molar ratio of reagents, time of mechanical activation and the mass of ball load. Under the optimal conditions, the yield of B2H6 is 30 to 50 %.

Natural experiment with underground draining of high-sulphide waste products from Karabash Copper-Smelting Combine (Chelyabinsk Region) by natural neutral water has been performed. An oxyntic potential and a quantity of Cu, Zn, and Fe that passed into solution has been determined; a change in fractional distribution of chemical forms of these elements in the solution and in saturation indexes of mineral phases with an increase in the water/rock ratio (W/R) during the course of the experiment has been calculated. It has been demonstrated that interaction of natural neutral water with the material of waste products yields acids and results in that more than 50 % Cu and Zn, and about 30 % Fe passes into solution to yield the ratio W/R = 400 : 1. It has been observed that at low W/R ratios in acidic medium, copper and zinc exist in the form of sulphate neutral complexes and activated ions, and zinc additionally forms an anionic sulphate complex. As washing of acid proceeds, the fraction of sulphate complexes decreases; the metals remain preferentially in the form of aqua ions. Iron that exists in the solution predominantly in a sulphate complex during the beginning of the experiment then changes to a hydroxide form. Processes of dissolution and deposition of mineral phases actively proceed during the experiment. Ferrihydrite Fe(OH)3 and goethite FeOOH that are produced by the end of the experiment facilitate sorption and coprecipitation of copper and zinc. Formation of a secondary sulphate, jarosite KFe3(SO4)2(OH)6, during the experiment is confirmed by data of X-ray crystal analysis.

Chemical and particle-size composition of slimes from accumulator factory has been investigated. It has been demonstrated that basic part of lead therein is presented by carbonate and oxidic compounds, and in view of fine dispersity of the products, conventional methods of producing lead from slimes are unsuitable. Laboratory tests of two variations of a cementation procedure to reclaim lead from sewage slimes of accumulator factory have been performed. They included the one with intermediate obtaining pure lead sulphate and with direct cementation of lead from a sulphate product. It has been demonstrated that both of variations provide practically complete regeneration of lead to yield marketable products. Advantages and limitations of both variations have been discussed.

The capability of YBa2Cu3Od for an intensive exchange with oxygen of a gas phase even at ambient temperature (ta) that has been detected previously has been studied with diversified physical methods. An X-ray photoelectron spectroscopy method has been applied to demonstrate that a degree of ionicity of cation-oxygen bonds increases during oxidation under the ta conditions. Along with this phenomenon, oxygen appears in a state that is close to chemically unbonded. This correlates with evidence on spontaneous electric polarization that emerges in yttrium-baric cuprate under the test conditions. The obtained result has been explained in the context of YBa2Cu3Od model as of a virtual ferroelectric, the critical temperature of which in certain conditions can grow up to high positive values. In so doing, modification of chemical state of [BaO2] structural group occurs from formal peroxide to formal oxide with strengthening of a certain Ba

An effect of conditions of hyperfine grinding on the size of crystallites and on the aggregation degree of received a-Al2O3 nanopowders has been examined. It has been demonstrated that the average size of crystallites of a mechanically grinded powder is a function of relative humidity in the barrels of a planetary mill with a pronounced minimum (200