Home – Home – Jornals – Thermophysics and Aeromechanics 2010 number 1

Problems concerning the migration of mercury vapor through different types of organomineral filters are considered, the absorbing capacities of the formed geochemical barriers are determined. The most promising types of geochemical barriers for the subsurface burial in the forest-steppe landscape zone are revealed. An approach to a decrease in mercury vapor evaporation by transforming into a more conservative phase of metacyanobarite modification of mercury sulfide (HgS) is proposed.

Chromium content of ground, dust and plants from the region near the open pit used to store self-decaying ferrochromium slag of the Chelyabinsk Electrometallugrical Plant was studied by means of X-ray fluorescence anаlysis involving the synchrotron radiation beams (RFA SR).

The effect of temperature on the number and activity of sulfatereducing bacteria was studied under the experimental and field conditions during the winter of 1988 at the Rybinsk water reservoir.

Zooplankton of the pelagian and shelf zones of the eastern coast of the South Baikal in the region of the Baikal Pulp and Paper Plant (BPPP) in summer and autumn periods of the years 2005-2007 was studied. It was established that the development of zooplankton during summer and winter 2005-2007 in the layer 0-50 m proceeded according to the scheme typical for Lake Baikal, in spite of the enhanced anthropogenic load in the region under investigation.

Buffer capacity of humic psammozem, accumulative carbonаte agrozem and agrobrown soil with respect to cadmium was determined. The effect of soil buffer capacity on the dynаmics of the height, biological productivity and the level of cadmium accumulation in the biomass of watercress (Lepidium sativum L.) under increasing metal doses was investigated. The ability of watercress to accumulate large amounts of cadmium exceeding the admissible sanitary-gygienic standards even at low concentrations of the element in the soil was established.

Investigation of the physical and technological characteristics of ash-and-slag wastes from the Kyzyl heat and power plant was carried out. Chemical, elemental and mineral composition of the products of fractional separation was studied. On the basis of the studies of the concentrations of hazardous substances in the fine fractions of ash and in ground water, it was concluded that the dusting fraction of ash-and-slag wastes produces the major effect on the environment as a result of air transport.

Post-fire changes of the functional characteristics of soil microbial coenoses and the complexes of soil invertebrates in the middle-taiga pine forests of Central Siberia were studied. It was revealed that the fire events, independently of their intensity, during the first year cause a decrease in the number of diversity of soil invertebrates, and also have a negative effect on the structure and the functional activity of microbial complexes of sandy podzol. The post-fire recovery of the number and structure of the complexes of soil invertebrates and the functionаl activity of microbial coenoses of sandy podzol is determined both by the action of the pyrogenic factor and by the features of the dynаmics of hydrothermal and trophic conditions of soil in pine forests.

Results of the determinаtion of salt-soluble form of iodine in the chernozem are discussed. This form is considered as the nearest reserve of iodine available for plants. With respect to this form of iodine, the chernozem is similar to hydromorphic soil.

Description of the interactive multiple-entry polyclave electronic key for identification of 102 species and subspecies of Siberian Astragalus is presented. At every step of identification, the program reduces the species list, reduces the state lists for qualitative characters, recalculates diagnostic values of characters and ranks the characters by their diagnostic value. In the process of identification, a user can return to previous steps of identification, to get text descriptions and drawings of a species and the photos of herbarium specimens, to use an interactive monoentry dichotomous key, to change and input new data into the data table. The program is workstation-based and implemented in Microsoft Access 2002.

A variety of vascular plants of two altitudinаl belts in the areas of upper rivers Kygam, Morgel and Lontoko is revealed. The geographical and ecological anаlysis of flora, as well as the anаlysis of life forms of each belt is carried out.
Comparison of three local florae in species composition showed isolation of the florae of golets and under-golets altitudinаl zone belts in the area of the river Lontoko from similar florae in the areas of the rivers Kygam and Morgel. Comparison between the florae in the ratio of latitudinаl elements revealed an intermediate position of the area of the river Kygam between the areas of the rivers Lontoko and Morgel. Comparison with respect to the ratio of ecological groups of species and life forms showed the similarity between the golets altitudinal zone and sub-golets altitudinal zone belts of the areas of the Lontoko and the Kygam, and their difference from the area of the river Morgel.
In the past (in the end of the small glacial age of Holocene), the Longtokojsky Stone ridge differed in flora from the florae of the basic area of the western part of Putoransky mountains stronger than it does today. This is connected with the less significant role of the Atlantic transfer in this region in the past and the more significant role of the Siberian anticyclone.

Results of the studies of variability of the morphological attributes and numbers of chromosomes in the populations of R. altaicus s.l., R. sulphureus subsp. exaltatus and R. schmakovii are presented. The methods of unidimensionаl and multivariate analysis were applied: princiрal-component method, discriminаnt and variance anаlysis. As a result, two buttercup subspecies were distinguished at the territory of the Altay mountain territory (R. altaicus subsp. altaicus, R. altaicus subsp. frigidus), as well as new taxons R. sulphureus subsp. exaltatus и R. schmakovii.

Analysis of the spatial arrangement of abies undergrowth with respect to abies, aspen and birch trees was carried out in the climax community of the dark forest by means of radial functions. The results of analysis showed that the abies undergrowth is concentrated mainly in the vicinity of old abies trees but its occurrence near abies stumps is much below the expected level. Such an arrangement of the undergrowth should inevitably lead to a decrease in the area occupied by the population of abies, and its number. The abies undergrowth is mostly concentrated in the vicinity of parvifoliate species where dense abies curtains are formed. Thus, the populations of parvifoliate species are the stabilizing factor with respect to the population of dominant species of the dark abies forests.

The objective of the research was to study phenology and the process of flowering of Gentianа scabra Bunge. Flowers in raceme blossom out from top downward. The flowering period of one flower is 10 days, and that of the whole plant is 30 days. 13 species of possible agents for pollen transference are found. It is shown that bumble-bees are the primary pollinating insects. Stigma receptivity to pollen decreases significantly 8 days after unfolding of stigma. G. scabra flowers are capable of self-pollinаtion. The main type of pollinаtion of G. scabra flowers is xenogamy which is consistent with geitonogamy.

Ecological and biological features of Pteridium aquilinum allowing the species not only to get adapted to the conditions of the moderate zone but also to dominate in the grass of the communities and get adjusted to new territories within the habitat are revealed. It is established that the conditions of the oceanic climate most completely correspond to the ecological optimum of Pteridium aquilinum, while in Siberia the species is at the Northern limit of its habitat.

Statistically significant effect of the factors of habitat conditions and the weather conditions of the year under investigation on the majority of morphometric parameters of the vegetative and generative spheres of four natural coenopopulations of Hylotelephium stepposum (Boriss.) Tzvel. and three coenopopulations of H. triphyllum (Haw.) Holub. was revealed with the help of two-factor variance analysis.

The review of the proceedings of the 2^nd International Conference on Conservation of Forest Genetic Resources in Siberia that taken place in August 3-9, 2009 in Novosibirsk, Russia is presented.

Here is the review of experimental and theoretical results on the mechanism of heat transfer in nanofluids. A wide scope of problems related to the technology of nanofluid production, experimental equipment, and features of measurement methods is considered. Experimental data on heat conductivity of nanofluids with different concentrations, sizes, and material of nanoparticles are presented. Results on forced and free convection in laminar, and turbulent flows are analyzed. The available models of physical mechanisms of heat transfer intensification and suppression in nanofluids are presented. There are significant divergences in data of different researchers; possible reasons for this divergence are analyzed.

Effects of the upstream conditions and the degree of the wall roughness on the mean velocity profiles and some integral flow parameters in two dimensional zero-pressure-gradient boundary layer were characterized experimentally. The results were analyzed utilizing conventional and recent scaling flow parameters for 245< Re_{θ ≤ 11·10³, where Reθ is the Reynolds number based on the free stream velocity and the momentum thickness (θ). Good correlation of the quantity as a function of the roughness parameter k^{+ was obtained for sand roughness of 1.7 < k+ ≤ 172, revealing a universality of the roughness effect, where =
= ( − )/uτ and k+ = kuτ /ν. The mean flow structure of the outer flow was observed not to be influenced by the degree of the wall roughness, i. e., the outer flow of either the smooth or the rough surfaces scales similarly with the various scaling parameters regardless the degree of the wall roughness. However, it made flow confined to the wall region away from the classical universality, allowing similarity hypothesis not to be identical in the wall region at least for the current range of the Reynolds number.}}

Results of experimental investigations of the evolution of a vortex system formed in a supersonic flow past a streamwise-aligned external dihedral right angle owing to a difference in pressures on the upper and side faces of the corner are analyzed. The experiments are performed in a T-313 wind tunnel based at ITAM SB RAS at Mach numbers М_∞ = 2.27, 3, and 4, and angles of attack α = −4° ÷ +20°. It is shown that the size of the vortex system influence zones is almost independent of the free-stream Mach number in the examined range of the angles of attack, and the relative values of flow rarefaction on the model surface under the primary vortex core smoothly tend to their minimum values.

The computational method for aerodynamic design of aircraft is applied more universally than before, in which the design of an airfoil is a hot problem. The forward problem is discussed by most relative papers, but inverse method is more useful in practical designs. In this paper, the inverse design of 2D airfoil was investigated. A finite element method based on the variational principle was used for carrying out. Through the simulation, it was shown that the method was fit for the design.

The results of designing and numerical gas-dynamic modeling a supersonic three-dimensional inlet of a new type are considered. A ramp of external compression of this inlet is the V-shaped body forming an initial plane oblique shock wave and a subsequent isentropic compression wave. The inlet incorporates an entrance section of internal compression, where also a plane oblique shock wave and a subsequent isentropic compression wave are formed by a cowl. The designed three-dimensional inlet has small inclination angles of compression surfaces, which ensures its low wave drag. According to the estimates of inlet efficiency in terms of the compression ratio and the total pressure recovery factor, it is close to the optimal two-dimensional shocked inlet of external compression considered by Oswatisch as well as Petrov and Ukhov. The flow in the inlet was computed with the use of the Euler and Navier ⎯ Stokes codes provided by the commercial package FLUENT. The flow in the inlet throat in the design regime computed under the inviscid flow approximation is uniform. The most substantial effect of the flow viscosity in this regime manifests itself in the interaction of the shock wave from the cowl with the boundary layer on the V-shaped compression body in the inlet internal duct. According to computed data, the boundary layer separation does not occur in this case; however, due to viscosity effects, reflected shock waves are formed here which results in significant deviations of flow structure as compared to the computed inviscid flow.

In the present paper, we introduce an experimental technique for evaluating the equivalent aerodynamic diameter d_{ae of non-spherical aerosol particles upon their sedimentation in a gravity field within the Reynolds-number range from 0.1 to 6.0. A description of the sedimentometer is given, and aerodynamic diameters dae of plexiglass powder particles measured on this sedimentometer are reported.}

Results of experimental study of the nonstationary temperature field on the surface of a complex shape channel at a jump-like change in heat release with time in the wall of packing with one-way heat supply are presented. Measurements were carried out in the air flow between two plates with triangular corrugations directed at 90° relative each other. Measurements were carried out by thermocouples with the thickness of less than 10 microns. The effect of Reynolds number and supplied power on the temperature change over the heat exchanger surface with time caused by a jump-like change in supplied electric power at a turbulent air flow is analyzed. Investigations have revealed typical features of temperature evolution over the perimeter of the heated cell. Experimental data on time dependence of temperature can be approximated well by the exponential function.

In the present paper, we consider the heat transfer of non-Newtonian liquid flows moving in convergent-divergent channels with common boundary. The case of flows moving in opposite directions was addressed. At the common boundary, continuity conditions for temperature and heat flow were adopted. A mathematical model, a calculation algorithm, and simulation data are reported. Plots of numerical data characterizing the channel flows are presented. A comparative analysis of heat transfer in smooth and convergent-divergent channels is given.

The gas-liquid upward flow was studied in a rectangular minichannel of 1.75×3.8 mm and length of 0.7 m. The experiments were carried out within the range of the gas superficial velocity from 0.1 to 10 m/s and the liquid superficial velocity from 0.07 to 0.7 m/s for the co-current H₂O/CO₂ flow under the conditions of saturation. The method for the two-beam laser scanning of structure and determination of statistic characteristics of the two-phase flow was worked through. The slug-bubble, slug, transitional, churn, and annular flows were distinguished. The statistics characteristics of liquid and gas phases motion in a minichannel were obtained for the first time including the velocities of phase motion.

Experiments on water cavitation in ultrasonic field have been carried out. Low frequency fluctuations of the intensity of laser beam run through the cavitation area have been studied. Experiments have proved presence of low-frequency random fluctuations with frequency dependence of power spectra where the exponent α ranged within 0.8 ≤ α ≤ 1.2. From experimental realizations, large-scale low frequency pulsations characterized by scale invariance, which duration is distributed according to the power law, have been distinguished. The results are explained on the basis of mathematical model for the rise of scale invariant fluctuations with power spectrum in the system of two nonlinear stochastic differential equations describing interaction of heterogeneous phase transitions. Distribution of extreme low frequency emissions obtained from numerical solutions to stochastic equations takes the power series form. Correlations of dynamic scaling between critical indicators determining frequency dependence of pulsations power spectra α and distribution functions of extreme low frequency pulsation amplitudes β have been determined. It is shown that both in the experiments on acoustic cavitation of water and in the theoretical model of interacting phase transitions critical indicators are bound with the correlation α + β = 2. Spectra of fluctuation power are determined in the experiments simpler and more accurately than the function of extreme amplitudes distribution. In case when only one frequency dependence of fluctuation capacity spectra is known correlations between indicators serve to obtain information on the distribution of large scale emissions and to estimate critical amplitudes.

Boiling-up kinetics of superheated distilled water and sodium chloride solution in a glass cell at atmospheric pressure and low superheating of 15−35 °C has been studied far from the boundary of attainable superheating in the area of heterogeneous nucleation. Temperature dependences of average waiting time of superheated liquids boiling-up have been studied experimentally under natural conditions and in the ultrasonic field Waiting time of boiling-up at these temperatures reaches 1000 s, and average time is 600 s. Empirical distribution functions have been found with the use of the waiting time samples obtained by the method of order statistics. Omega-square goodness-of-fit test has shown that they disagree with exponential distribution describing stationary random process of supercritical embryo generation separating the system to macroscopic phases. Thus, it is shown that this random process is not stationary, consequently, nucleation rate to be depending on time.

Results described in the work were obtained in the investigation of the activity of oxide materials prepared by depositing copper oxide on aluminium oxides with developed surface (5-26 % CuO/Оі-Al₂O₃ and 28 % CuO/Оё-Al₂O₃), towards hydrogen absorption at a temperature within the range 25-90 ^оC and hydrogen pressure 40 torr. It was demonstrated that the samples with the high copper oxide content are characterized by satisfactory specific rate of hydrogen oxidation and may be used as the absorbers of hydrogen released during radiolysis, during the transportation of mixed radioactive wastes in tight vessels.
hydrogen, low-temperature oxidation, solid oxidants, copper-containing oxide systems

It is shown using mass spectrometry and gas-liquid chromatography that drinking water entering water pipelines contains a number of dangerous impurity microelements and chlorinated organics with concentrations close to MPC (except iron and manganese). It was established that the treatment of drinking water with ozone followed by filtering through a coal filter (household device "Ozonid-rodnik") and freezing at -18 ^оC under home conditions provide efficient additional purification. Purified water does not contain carcinogenic chlorinated organics, while the concentrations of dangerous microelements (As, Cd, Ni, Cr, Pb, Se, V, Sb, Hg) decreases by a factor of 1.5-4.5, Fe, Mn, Al by a factor of 2-15.

Composition of coal from the new northern deposits of the Lena Basin and its reactivity in the processes of thermal dissolution and hydrogenation were investigated. It was established that the content of rare earth elements in the coal under investigation in some cases is 5-10 times higher than the industrially significant indices. The results of thermochemical transformation of coal into liquid substances are presented. Qualitative relations between the transformation degree during thermal dissolution and the data on the technical analysis of carbon - hydrogen concentration and the yield of volatiles - were determined. The suitability of the coal from the Lena Coal Basin for obtaining liquid fuel by means of the catalytic hydrogenation is substantiated. The reasonableness of complex processing of coal with the separation of rare earth concentrate is stated.

Efficiency of water purification k_pur from metal sulphates (MnSO₄ в‹… 5H₂O, FeSO₄ в‹… 7H₂O, CuSO₄ в‹… 5H₂O and VSO₄ в‹… 5H₂O) is investigated as the dependence on the fraction of frozen aqueous solution (g) and freezing temperature T. The following kinds of dependencies were established: 1) a monotonous decrease in k_pur; 2) a monotonous increase in k_pur; 3) an increase in k_pur with an increase in the fraction of frozen solution to g > 0.3-0.4 followed by a decrease at g > 0.4 (non-monotonous dependence). The influence of reasons preventing high k_pur is discussed. These reasons include the impossibility to separate the drops of liquid solution containing impurities from the surface of ice, due to the sampling method (adhesion factor) and freezing of the impurities into the interdendritic cavities on the surface of the freezing front (dendritic factor).

On the basis of the data of hydrochemical analysis carried out during the years 1938-1939, changes in the composition of water in Lake Bolshoy Vudyavr under the action of waste water from the mining industry is investigated. The complete geochemical composition of natural water is reconstructed using thermodynamic methods; the ecological state of Lake B. Vudyavr is evaluated. The results are of practical and methodic significance for predicting long-term anthropogenic impacts on the water systems of the Subarctic territory.

Chemical composition of humic substances from brown coal of the Sergeevskoye deposit is studied by means of elemental analysis, IR and ¹³С NMR spectroscopy. A comparative analysis of the fragment composition of coal fractions is carried out. It is shown that extraction of humic acids is accompanied by oxidation-reduction transformations. The data on the polyfunctional composition and potential of physiological activity of humic substances provide evidence of the possibility to use coal from Sergeevskoye as a source of humic fertilizers.

Influence of the nature of fossil fuel on the yield and component composition of the products of ozonation in glacial acetic acid is studied. It is established that the basis of compounds soluble in the reaction medium is the low-molecular water-soluble compounds. Among water-soluble products of humic brown coal, prevailing compounds are benzene dicarboxylic acids and their alkyl derivatives. The products of ozonolytic destruction of liptobiolite and sapropelite coal are represented mainly by aliphatic carboxylic acids with chain length С₂-С₁₀.

Cyanide regeneration by means of electrochemical oxidation of the acid solutions of thiocyanates is investigated. The effect of reagent concentrations, current density and method of process performance on the efficiency of thiocyanate oxidation and the mass yield of cyanide is studied with model and technological solutions.

It is shown by means of thermogravimetry, differential thermal analysis, mass spectrometry, IR spectroscopy and electron microscopy that the character of cellulose thermal transformation changes and the yield of carbon residue increases during cellulose heating in the presence of SiO₂ and polycarbosilane within temperature range up to 900 ^оC. In the case of polycarbosilane addition, silicon is present in the cabon material in the form of organosilicon fragments with Si-C and Si-O-C bonds, as well as in the form of silicon oxycarbide. With the addition of SiО₂, the major amount of silicon is conserved in the form of oxide; the amorphous modification within the composition gets transformed into cristobalite.

Comparative analysis of the efficiency of oxidation of sulphureous compounds of diesel fraction by various oxidants (ozone, peroxides) in a two-stage process of sulphur removal (a combination of oxidation and adsorption) was carried out. The dependence of the oxidation degree of sulphurous compounds of the diesel fraction on the amount of the oxidant used and on the process conditions were investigated. The changes in the group composition of saturated and aromatic hydrocarbons, sulphureous compounds of the saturated and aromatic character under the oxidation of the sample followed by adsorption purification of the resulting products were analyzed.

To obtain high-resolution records of elemental paleoenvironmental change proxies in the bottom sediments of Lake Hovsgol (Mongolia), a high-performance technique is proposed. It consists of extraction of sediment samples with 1 % HNO₃ followed by multi-elemental ICP-MS measurements of extracts. In comparison with the complete decomposition of bulk samples, this method provides a maximal number (44) of climate-sensitive elemental signals (variation of contents of extractable elements along sediment core depth) and, at the same time, their maximal response to the global paleoclimate change. The highest sensitivity (variability >100 %) to climate change is characteristic for С_inorg, P, Ca, V, Ni, Se, Br, Sr, Mo, Sb, I, W and U, and the lowest one (25-30 %) - for As, Rb and Pb. On the basis of memory effect studies, an algorithm of ICP-MS measurement (VG PlasmaQuad II quadruple spectrometer) is proposed; this method does not require intermediate rinsing of spectrometer measuring path between core samples analysed subsequently. It allows increasing the output of serial analysis up to 200 samples per day.