Home – Home – Jornals – Contemporary Problems of Ecology 2007 number 6

Classification of the bird population of the West-Siberian plain and the Altay is carried out; the structure of the spatial variability of ornithocomplexes is revealed. With the help of qualitative linear approximation (a qualitative analogue of the regression model), the informative content of the obtained classification and structural representations is calculated.

Fires in the pine forests of Middle Siberia make a substantial contribution into carbon resources. The emission value is essentially affected by the intensity of forest fires, types of vegetation, and the conditions existing at the grow sites. During extremal fire-risk seasons, emissions from forest fires can increase several times. The duration of an average interval between fires decreases from the north to the south and is determined by the latitude and by the degree of landscape apartness, as well as by the anthropogenic load.

The comparison between the coenofloras of Yamal and Taymyr for three subzones is carried out: southern, typical and Arctic tundras. The parameters of activity and richness of species of the life-forms in coenofloras were used. The an

Spatial-temporal superposition of the data on large forest wildfires and lightning are an

An

Bacteria of Enterobacteriaceae family were isolated from the soil, tissues and surface of a number of wild and cultivated plants. All the isolated cultures exhibited a wide range of stability against 11 antibiotics and high adhesiveness to human erythrocytes. Investigation showed the possibility of concentrating the microorganisms that are pathogenic for humans in plant tissues.

Bogs occurring at the territory of natural park

Results of the investigation of the siberian species of Myricaria Desv. genus are reported. Myricaria is a shrub the biology and ecology of which are still poorly investigated. It grows on pebble and rocky banks of the mountainous rivers in the southern regions of Siberia. The ecological features of blooming, bearing, ri

The paper briefly describes the life and activities of F.A. Zander and Yu.V. Kondratyuk (A.I. Shargei), pioneers of domestic rocket engineering who made a significant contribution to the development of cosmonautics and rocket technologies. The main ideas and proposals of these prominent scientists and inventors in the field of rocket and space engineering, which found their application in space conquering, are considered.

This paper deals with adiabatic evaporation of various liquids into an air-steam mixture and pure superheated steam. The focus is made on the inversion temperature, which means that the rate of liquid evaporation into an air-steam mixture (superheated steam) becomes equal to the rate of evaporation into dry air. A simple analytical solution for finding of inversion temperature was derived, and the required conditions of existence of the given phenomenon are found. The influence of parameters of the main flow (vapor quantity, pressure, and flow regime) on the value of inversion temperature is analysed. It is shown that consideration of the influence of injection flow on relative function of heat transfer for inversion temperature definition of ethanol, acetone, and benzene is necessary. A comparison with numerical modelling was made to estimate the analytical solution accuracy.

Transitional processes with dry spot formation and drying crisis development were studied experimentally for the gradual and quasi-stationary laws of heat release on a thin-wall heater cooled by a falling film of cryogenic liquid. It is shown that for low densities of the heat flux, the laminar-wave liquid film decays with formation of a self-organizing system of metastable regular structures with boiling liquid jets and large dry zones between them. The numerical experiment modelling the process of repeated wetting of a superheated surface dried by impulse heat release was carried out. It was found for the first time that the local motion velocities of different zones of the 2D wetting front differ significantly. Reliability of results obtained by numerical methods was proved by direct comparison with experimental data.

In the present study, the flow field near the orifice of a plane wall jet is in focus. Two main flow regions may be distinguished in the wall jet, i. e., a free shear layer away from the wall and a boundary layer close to the surface. In both of these layers, streamwise coherent structures are detected by means of smoke visualization and hot-wire measurements. The structures, which occur naturally, have different spanwise scales and emerge at different distance from the nozzle. Effects of the flow velocity, upstream perturbations, and acoustic excitation on the generation and characteristics of the streamwise disturbances are investigated, and especially the interaction between the two layers is studied. In order to resolve the complex 3D flow by means of hot-wires a system for accurate automated traversing and data acquisition has been developed. In each flow case time-dependent measurements were taken in (X, Y, Z) space of about 3000 to 25,000 points, and it was found that the value of outlet velocity and the frequency of Kelvin

Temperature distribution and intensity of temperature pulsations in the airflow in a complex heat exchanger of

The viscous incompressible medium (water, air) flow past a circular cylinder is considered with regard for the temperature Т dependent viscosity n . The influence of different boundary conditions for temperature on flow structure, the drag coefficient and its components due to the pressure and viscosity is investigated in the problem of the flow past a cylinder at rest for the (diameter-based) Reynolds number Re_D = 40. A relation between the viscosity gradient along a normal to the body surface and the integral vorticity flux from the body surface into the boundary layer is discussed. Unlike the constant viscosity case the vorticity flux may be different from zero, which must lead because of the integral conservation law for the vorticity to an alteration of the far-field boundary conditions for the velocity. In the same connection, the problem is analysed on the heat spot entry into the computational region under consideration for the flow past a circular cylinder. The examples of the symmetrization of separated flow past a cylinder performing rotation oscillations in a uniform free stream (the Taneda problem) are considered. A comparison with flow computations for low Mach numbers М < < 1 for the flow of a medium past a cylinder at rest is carried out. At the computation of the equation for heat transfer under the assumption of incompressibility of such media as air, it is proposed to retain the pressure derivative, which is typical of gases. In this case, a better agreement with the computations of compressible flows (for М < < 1) is achieved, for example, at the determination of the sizes of a symmetric zone of flow separation past a circular cylinder. An unsteady flow in the neighborhood of the point of joining the zero streamline bounding a closed region of separated flow (the cavity) in a wake of the cylinder at rest is obtained by a numerical simulation at the Reynolds number equal to 40.

The matter of development of a high-performance pressure recovery system (PRS) for a high-power HF/DF laser is discussed. A sequence of design steps is proposed, which involves estimation of basic characteristics of PRS components with the help of one-dimensional integral and semi-empirical procedures; simulation, to be performed using three-dimensional non-stationary Navier

A numerical model for solving the Boltzmann unsteady non-local kinetic equation for the distribution function of electrons over energy is constructed. The Boltzmann equation for isotropic part of the distribution function written in natural variables the kinetic energy

The developed general physical-mathematical model, FEM-based calculation procedure as well as the software were in practical use to simulate the processes of the non-stationary conjugate heat exchange and phase transformations during the processing of the surface with a high-concentrated energy fluxes, with a stationary, pulsed, and movable heating sources (the processing, including the surface fusing with a quasi-laminar plasma jet, transfer electric arc and impulse electron beam; cleaning of the metal substrate surfaces from an oxide layer with the aid of a cathode vacuum arc, etc). The processes of practical importance with considerably different spatial and temporal scales featuring the density of the heat fluxes power q 

The possibility of efficient application of plasma equipment for gasification of various technogeneous carbonaceous wastes (domestic wastes, waste wood, rice hull, biologic wastes) is studied. Gasification of carbonaceous wastes is analysed thermodynamically. Possible prediction of gasification results is proved experimentally using the plasma equipment. It is shown that syngas appropriate for needs of power engineering and chemical industry is produced at plasma gasification of carbonaceous materials.

The axisymmetric problem of thermal energy accumulation in a material undergoing a phase transition at its interaction with a heat-transfer agent whose temperature varies cyclically is considered. The possibility of choosing the parameters of an accumulator part design, where the material is stored, is investigated by numerical methods. An optimal volume of the heat-accumulating material is determined from the condition of the equality of the heat amount at the accumulator charge- discharge. Results computed for the laminar and turbulent regimes of heat-transfer agent supply showed that the turbulent regime is the most efficient for the same heat-exchange surface.

A calibration technique for the constant-temperature hot-wire anemometer is presented, which is based on traversing the probe through the boundary layer of a flat plate while simultaneously performing fluctuation measurements. The free stream Mach number was M = 2.54, and the Reynolds number Re_d, based on wire diameter, ranged from 9 to 23. A comparison of the sensitivity values obtained with the aid of such a calibration procedure

The results of experimental research on interaction between an axisymmetric underexpanded jet and obstacles of various shapes (the plane one and in the form of a cylindrical cavity) are presented. It is found that a cavity provides formation of a reverse flow, whose interaction with a jet causes formation of the vortex spiral structures.

A flow reactor was used to study the kinetics of 5-hydroxymethylfurfural synthesis from fructose and sucrose at 240 oC in water solutions containing acetic and phosphoric acid as catalysts. The maximum yield of 5-hydroxymethylfurfural was found to be practically independent of the chosen catalyst and carbohydrate. It attained 40 mol. % at 240

Influence of the water content of milling medium on the properties of reaction bonded aluminium oxide powder precursors and their sintered mechanical properties is studied. As a result of interaction between absolute ethanol and aluminium, the water content of the mixture milled in absolute ethanol increased to 4.7 %. Mechanical properties such as bending strength and toughness of the sintered ceramics depend on the water content of the powder precursors. Higher bending strength, 350 MPa and toughness, 3.7 MPa m1/2 were observed in the sample milled in absolute ethanol. Higher water content of the mixture milled in absolute ethanol is the main reason of the high mechanical properties.

Initial stage for preparing alumina supported metal catalysts according to a scheme, essentially reducing harmful wastes, is discussed. Preparation method is based on a direct interaction of pretreated metallic aluminum with water. Diffusion phenomena are shown to be the core of aluminum activation by metallic In

Liquid products of the autoclave hydrogenation and hydropyrolysis of the Barzas sapromixite were studied. Chromatomass spectrometry was used to determine the content of individual substances in the low boiling fractions. Hydropyrolysis product appeares to consist of normal paraffins by more than 50 mass %. Hydrogenation products is characterized by a higher content of cyclic and structure isomerized paraffins. Aromatics content in both products does not exceed 14.1 mass %. IR and NMR spectroscopy show that fractions boiling above 180 oC contain mostly aliphatic fragments. Hydropyrolysis products composition is similar to that of oil, while hydrogenation product is characterized by more aromatic and shorter aliphatic fragments per statistically average molecule. If mechanically activated iron ore catalyst is used at the sapromixite hydrogenation and hydropyrolysis, the contribution of distillate fractions increases, and low boiling (boiling start 180 oC) fractions contain more low molecular mass hydrocarbons.

The behaviour of phosphate anion

Sulphuric acid leaching of sulphide ores assisted by nitrous compounds in Udokan copper deposits was studied regarding the effect of low and high temperatures. Negative temperatures were found to intensify the leaching of copper dramatically. Nitrous acid appears to be the catalyst of the process. Experimental results show that heavy metals in the cryogenic zones of sulphide ores demonstrate high mobility at oxidation processes assisted by nitrous compounds.

A set of problems and directions of the accelerated development of methods to synthesize perfluoroalkane-2,3-epoxides by means of the oxidation of fluorine-containing olefins is considered. Attention to perfluoroalkane-2,3-epoxides is due to their promising use in obtaining fluorinated materials for a wide range of practical applications: for example, as monomers for obtaining polyfluorinated polyethers, for manufacturing fluorinated membranes for electrochemical processes. The effect of the nature of oxidizing agent, radical initiators and the structure of a perfluoroolefin on the yield of the target product and on the formation of polymerization products is investigated. The application areas are proposed.

It is established that the content of lanthanum and neodymium accumulated in plant roots is several times higher than their content in the top mass. Rare-earth elements are most actively accumulated in pea roots. With respect to the coefficients of biological absorption, lanthanum and neodymium are characterized by low and middle level of absorption in the top mass of corn and pea.

On the basis of the data of IR spectroscopy and X-ray phase analysis, it was established that poly-N-vinyl pyrrolidone enters chemical interaction with organic acids during their joint mechanical activation. The character of this interaction depends on the nature of an acid but does not depend on the type of activator, while the duration of the interaction depends both on the nature of an acid and on the type of activator.

The mineral and microelement composition of gallstones extracted from patients in the Novosibirsk and Omsk Regions were investigated. It was stated that a common feature of choleolithiasis in the regions under comparison is noticeable predominance of cholesterol gallstones. It was shown that the prevailing element in gallstones is calcium, while differences in content and distribution of microelements in gallstones is determined by regional features. It was established that the main elements of bile are sodium, potassium and phosphorus, which is in good agreement with literature data.

Outlook for application of amorphous sorbents on the basis of titanyl hydrophosphate to decontaminate liquid radioactive wastes from  137Cs, 134Cs, 90Sr, and 60Co radionuclides with elevated (up to 32 g/l) salt background that corresponds in composition to see water has been shown. Impurities in the form of petroleum derivatives (up to 0.4 g/l) and solid suspensions have no considerable effect on the deactivation and they can be separated together with the waste sorbent from the being cleared solution. The flow chart for the decontamination has been suggested. Heat treatment of the waste sorbent enables conducting immobilization of radionuclides within a solid phase. A variant of deactivation of soils that are polluted by radionuclides has been suggested.

Investigation of a series of fine powders of the copper alloy with the addition of 15 mass % tin,
4 mass % nickel and 5 mass % phosphorus was carried out by means of X-ray photoelectron spectroscopy. It was shown that the chemical composition of subsurface layers of powder particles of the solder depends on preparation procedure and affects the quality of soldering.

Compounds of Pd(II) of the PdL2 formulation with perfluorinated thiols of aromatic series 4-CF3C6F4SH (HL1), 2,4-(CF3)2C6F3SH (HL2), 4-nonafluorodiphenylthiol C6F5C6F4SH (HL3), 2-heptafluoronaphthalenethiol C10F7SH (HL4), and phenolic antioxidant 2,6-di(tert-C4H9)-4-(CH2)3SH (HL5) have been obtained that feature a rather weak smell for mercaptans. The HL3 structure has been determined by the X-ray diffraction analysis method. Thermal properties of Pd(L1)2

Pilot trials of a new nanocomposite mesopore sorbent of the NCMS type have been conducted in a purification technology for slightly acidic sewage from mercury. According to the trials, the dynamic capacity with respect to mercury of the NCMS sorbent was equal to 25.6 mg/g. Atomic emission spectroscopy method with the application of a two-jet plasmatron and a registration scheme was used to receive data on the nature of quantitative distribution of mercury and associated impurity-metals (lithium, sodium, potassium, and calcium) across the layers of a sorbent load. It has been demonstrated that the NCMS sorbent concentrates preferentially mercury and potassium, and their mutual ratio is close to the formulation of K2HgI4 compound, while impurities of other metals practically do not accumulate in the sorbent.

Physical and chemical composition of the stored waste wood taken from the pits of the Ust-Ilimsk Timber Industrial Complex (TIC) was investigated. The microbiological and sanitary-hygienic status of the waste wood was examined. The experimental data obtained provide evidence that the mass in the pits is friable because of large-size wastes, so oxygen access is provided even to the deep layers in the pit. Aerobic microorganisms (fungi and bacteria) that had occupied the lowest old layers have already created a united community that carries out biochemical destruction of waste wood forming ecologically dangerous lignin-like substances, neutral compounds, phenols and acids. Intense microbiological activity can lead to spontaneous ignition of waste wood, which belongs to the class of fire dangerous substances.

It has been demonstrated that introduction of caprone fibre in SKS-30 ARK latex makes it possible to reach its uniform distribution in the polymeric matrix and to increase a yield of coagulum. The availability of interfacial interaction between the surface of the fibre and styrene butadiene rubber matrix has been found. The introduction of caprone fibre makes it possible to enhance the vulcanizate resistance to heat ageing, repeated strains, and tear.

The possibility of a substantial decrease in the amount of industrial wastes by supplementing the technological process with the stages performed by means of electrolysis was demonstrated for the examples of processes of isolation of elemental arsenic from the aqueous solutions of sodium arsenite, syntheses of the esters of phosphic acid from elemental phosphorus, obtaining arsenic acid by the electrolysis of a suspension of arsenic (III) oxide, synthesis of azodicarbonamide, ketopanlactone and arsine.

Granulometric and chemical composition of the ash-and-slag wastes (ASW) of fuel-bed firing of the brown coal from the Kangalas field of the Lena basin was investigated. The ash-and-slag material was separated by means of magnetic separation of the granulometric and hydrodynamic classification. The content of rare elements (RE) and rare-earth elements (REE) in the initial ash-and-slag and in separation products differing in particle size, density and magnetic properties was determined. It was shown that RE and REE content of the low-density products of hydrodynamic separation increases, while it decreases in the magnetic products. Manganese is also observed to get concentrated in the latter. In view of the low content of RE and REE in low-density products in comparison with the matter from ore deposits, it is concluded that the isolation of the metals from the investigated ASW is unreasonable. It was shown that the use of the investigated ASW in construction industry is promising; the compositions for obtaining nonfired bricks and building mortars of the grade strength were chosen.

The effect of humic substances on bioconversion of glucose into ethanol is investigated. It is established that their presence in the reaction mixture with the optimal concentration of 0.001 % accelerates fermentation process. The reaction of glucose fermentation can be recommended for use as a new rapid and economic test for the biological activity of various humic preparations and optimization of their concentrations in aqueous solutions, which can be used, for stimulation of the growth of microorganisms, plants, and animals.