Home – Home – Jornals – 2019 number 2

The bank of spectral line parameters of the principal isotopologue of the hydrogen sulfide molecule (H₂³²S) is presented. The databank is based on the global simulation of the line positions and intensities of this molecule performed within the method of effective operators. The parameters of the global effective Hamiltonian and of the effective dipole moment operator were obtained by their fittings to, respectively, the observed line positions and intensities, taken from the literature. The databank covers the 552.76- 8424.32 cm^-1 spectral range and contains the calculated values of the following spectral line parameters: line position, line intensity, energies of lower and upper states, Einstein coefficient for the spontaneous emission, and the statistical weights of the lower and upper states. The intensity cutoff was chosen equal to 10^-28 cm/molecule at T = 296 K. In total, the databank contains about 88 thousand lines. This databank is deployed on the website of V.E. Zuev Institute of Atmospheric Optics SB RAS (ftp://ftp.iao.ru/pub/H2S/).

We compare the time variations in monthly average concentrations of black carbon in the surface atmospheric layer, obtained from field measurements ([BC]) and from MERRA-2 reanalysis ([BC]_M) at four monitoring sites located in the northern part of Russia (Tiksi Hydrometeorological Observatory (HMO), Pechora-Ilych Biosphere Reserve, Alaska (Barrow), and Greenland (Summit). It is shown that the MERRA-2 reanalysis data for the regions of Tiksi HMO and Barrow not fully reflect the [BC] variations during the year, in contrast to the Pechora-Ilych Nature Reserve, where the differences are within 30-50%. The [BC]_M reanalysis data for the Summit monitoring site qualitatively agree with the measurement data characterizing the BC content in the free troposphere, but they underestimate [BC] by more than 2 times. In general, the analysis showed that the results of the MERRA-2 reanalysis of the monthly average values of the surface concentration of atmospheric black carbon can be used for climate assessments for hard-to-reach northern regions in the warm season with an error of about 30%. Possible reasons for the differences between [BC] and [BC]_M are discussed for different seasons and observation sites.

The rates of CO₂ anthropogenic emissions are estimated for Saint Petersburg and Moscow megacities based on satellite CO₂ measurements by OCO-2 instrument. The CO₂ emission rates for Saint Petersburg amount to 80 and 74 t/km² per day on March 1, 2016, and May 12, 2018, respectively. The CO₂ emission rate for Moscow is estimated as 123, 179, and 186 t/km² per day for August 25, 2018, June 22, 2018, and March 26, 2017, respectively. The comparison of our results with the estimates for other megacities has shown that the emission estimates for Saint Petersburg are close to those for Los Angeles and Berlin, and estimates for Moscow are close to those for London. The estimation errors are mainly caused by the anthropogenic contribution, which varies from 30% to ~ 90%.

A methodology for studying seasonal variations in cloud parameters over the regions of Western Siberia using satellite data is presented. Five natural zones have been identified: tundra, forest-tundra, bogs, taiga, and forest-steppe. A combined “summer” and “winter” cloud classification has been introduced including 16 and 12 cloud types, respectively. An algorithm based on neural network technologies and fuzzy logic methods is used for cloud image classification. The results of analysis of seasonal variations in some parameters of various cloud types and their repeatability over the considered regions of Western Siberia based on MODIS satellite data for 2017 are discussed. The dependences found for seasonal variability of cloud parameters are in a good agreement with the known literature data that confirms high efficiency of the technique proposed.

The results of stratospheric aerosol observations at lidar stations of Roshydromet after the explosive eruption of the Raikoke volcano (Kuril Islands, 48.29° N, 153.25° E) in June 2019 are presented. By using direct trajectory analysis and observational data of the Caliop satellite lidar the aerosol trace in the stratosphere is revealed from the volcano around the pole to Western Siberia within a month after the eruption. The lidar measurements of volcanic aerosol from the end of July 2019 at the Roshydromet lidar stations in Obninsk, Znamensk, Novosibirsk, and Petropavlovsk-Kamchatsky are presented. Volcanic aerosol was observed in the layer from 13 to 18 km. The integral backscattering coefficient in the layer varied from the maximum (0,8-1,6) × 10^-3 sr^-1 in August-September 2019 to (0,2-0,3) × 10^-3 sr^-1 by the end of the year.

The results of calculating the mean intensity and the mean power of laser radiation backscattered by a remote atmospheric layer and detected in the source plane are presented. Behavior of the mean intensity and the mean power of laser echo signal as functions of the refractive turbulence strength, the inner turbulence scale at the different diffraction regimes at the transmitting aperture, and sizes of the receiving aperture are studied.

The UV (355 nm) eye-safe turbulent lidar BSE-5 designed for atmospheric turbulence studies is described. Lidar works on the effect of backscattering enhancement, which occurs when a light wave propagates twice in a random medium. The design of the device is based on the receiving and transmitting afocal Mersen telescope, which provides thermomechanical stability during long-term operation of the device. To reduce the size of the telescope, the edges of the main mirror were cut off, which are not used during the lidar operation. Lidar tests were conducted at Tolmachevo airport, during which the turbulence condition was continuously monitored over the runway and over the aircraft parking. The lidar confidently recorded a turbulent wake for any aircraft type during takeoff and landing. It was found that the track width is 50 m wide, and the lifetime of the intense artificial turbulent zone over the airfield is 2-3 minutes.

The transmission spectra and methane absorption coefficients are compared for different instrumental functions of the spectral distribution of laser power using different sources of spectroscopic information. An expert list of methane lines is compiled.

We present the experimental results on electric and magnetic fields generated under breakdown and pre-breakdown modes of pulsed laser radiation propagation along atmospheric paths. It has been established that quasiperiodic electric and magnetic fields (105-106 Hz, duration of 10-100 ms) are generated during propagation of ms CO₂ laser pulses in the atmosphere under breakdown and pre-breakdown modes. The strongest induced electric and magnetic fields are observed at the number of breakdown centers per unit path length N_Nh = 0.17 m^-1. The connection of electric and magnetic fields arising around the ionization channel with the atmospheric parameters is shown.

A basic platform for photodetector modules used in the lidar complex for recording backscattered radiation in the near-infrared region is described. High-voltage pulse noise of DC/DC converters in the photodetector modules are reviewed and tested. A method is proposed for compensating the noise generated by such converters. The tests carried out in the lidars of Institute of Atmospheric Optics SB RAS showed the effectiveness of the module designed to record signals in analog mode at a wavelength of 1064 nm.

Relations and calculation results are presented for determining the effective thickness of the deposited water vapor layer and the effective optical path length adjusted by the absorption capacity of carbon dioxide to the surface layer, taking into account the sphericity of the earth's surface for the operation of infrared optoelectronic systems on slant paths at elevation angles of less than 20°.

The first results of comparative measurements of altitude profiles of concentrations of carbon dioxide and methane from the aircraft laboratory YAK-42D "Roshydromet" are presented. The data were obtained both in real time using devices operating on the basis of diode laser spectroscopy and in laboratory conditions with the use of a Fourier spectrometer by processing air samples collected in special flasks during research flights.

A slow laminar flame which is a thin (less than 1 mm) gas layer separating media of different densities is proposed as the inerface between gaseous media for laboratory studies of Richtmyer-Meshkov and Rayleigh-Taylor instabilities. The potential of the proposed approach to produce an interface is shown by the example of shock-wave interaction with a laminar flame in a lean (6 vol. %) hydrogen-air mixture. The development of Richtmyer-Meshkov instability at the interface between a heavy (cold) and a light (hot) mixtures was recorded by shadowgraphy.

This paper describes results of an experimental and numerical study of a magnetic-hydrodynamic (MHD) method for controlling a hypersonic ( M = 6) airflow in which a launched device of typical configuration is located. The experiments are carried out using an MHD testbed based on a shock tube. The flow in front of the solid is ionized using an electric discharge in an external magnetic field with an induction B =0.80-1.58 T. Conditions corresponding to the experimental conditions are numerically simulated using the Reynolds-average steady Navier-Stokes equations. The MHD interaction region is simulated by isolating a zone in front of the blunt part of the model with given force and heat sources. It is shown that, as a result of strong MHD interaction, the head jump moves away from the model surface and the heat flux to the body decreases with a value of the Stuart number S =0.1-0.3.

Stretching and breaking of shaped-charge jets and the behavior of the strained metal are studied with the use of dislocation mechanisms of plastic straining and with due allowance for shock wave processes at the stage of liner implosion and jet stretching. Regular features of shaped-charge jet stretching and breaking are found. Equations are derived for analyzing the influence of the strength and plastic properties of the material, its microstructure, geometric parameters, and kinematic characteristics on jet stretching and breaking.

To improve the penetration performance and distribution homogeneity of multi-explosively formed penetrators (MEFPs), the factors that affect their configuration, velocity, and distribution characteristics are studied using a three-dimensional LS-DYNA coupled hydro-code. Three different kinds of integral MEFPs are tested in experiments. The results show that the arc plane liner of uneven thickness is easier to form MEFPs with a large length to diameter ratio. Tantalum and copper MEFPs have good penetration performance due to a higher length to diameter value and kinetic energy. The arc bracket and the equidistant array pattern of the liners are beneficial for obtaining better distribution homogeneity of MEFPs.

A group analysis of the second-order equation including one-dimensional gas dynamics equations in Lagrangian coordinates as a particular case is performed. The use of Lagrangian coordinates makes it possible to consider one-dimensional gas dynamics equations as a variational Euler-Lagrange equation with an appropriate Lagrangian. Conservation laws are derived with the use of the variational presentation and Noether theory. A complete group classification of the Euler-Lagrange equation is obtained; as a result, 18 different classes can be classified.

In this study, an artificial neural network (ANN) is used to develop predictive models for estimating molecular diffusion coefficients of various gases at multiple pressures over a large field of temperatures. Two feed-forward neural networks NN1 and NN2 are trained using six physicochemical properties: molecular weight, critical volume, critical temperature, dipole moment, temperature, and pressure for NN1 and molecular weight, critical pressure, critical temperature, dipole moment, temperature, and pressure for NN2. The diffusion coefficients are regarded as the output. A set of 1252 gases (941 non-polar and 311 polar gases) is used for training and testing the ANN performance, and good correlations are found (R =0.986 for NN1 and R =0.988 for NN2). The result of the sensitivity analysis shows the importance of the six input parameters selected for modeling the diffusion coefficient. Moreover, the present ANN model provides more accurate predictions than other models.

This paper describes a numerical simulation of an unsteady axisymmetric flow in a shock tube, which arises as a strong shock wave incident on the end face of the tube is reflected under conditions in which a chain of shock waves is formed after the reflected shock wave, similar to a pseudo-jump in steady flows. The conditions under which this flow is formed are understudied. The flow is investigated in the case of the shock tube in which an incident shock wave is formed and moving at a velocity corresponding to the Mach number M =2.6. The numerical calculation is carried out using the Reynolds-averaged Navier-Stokes equations and the SST-(k-ω) model of turbulence. The resulting data are compared with the known experimental data and the results of numerical calculations.

Results of experimental and numerical modeling of supersonic under expanded jets exhausting into a slotted submerged space formed by two parallel disks are presented. It is demonstrated that the structure of the exhausting off-design jet depends on the distance between the disks. The friction force acting from the disks on the gas is responsible for significant changes in the supersonic jet structure. At a certain distance between the disks, there arises a curvilinear shock wave, followed by a subsonic flow region. In this case, the jet boundary acquires a fan-shaped structure rather than a typical barrel-shaped structure.

An axisymmetric laminar swirling jet of a viscous incompressible fluid flowing from a rotating semi-infinite tube in space filled with the same fluid is explored. The inner surface of the tube rotates with a constant angular velocity, the outer surface is stationary or rotates with the same angular velocity. It is shown that in the first case, the flow field far from the tube orifice is described by the Loitsyansky asymptotic solution, and in the second case (with a weak coflow flow), it is described by the Long-Goldshtik-Zoubtsov self-similar solution. The Goldshtik hidden invariant is generalized to arbitrary axisymmetric swirling jets, and its influence on the jet asymptotics is studied. Strong swirling jets are calculated, and the dependence of the parameters of the recirculation zone (vortex breakdown in a swirling jet) on the swirl number and the Reynolds number is examined.

A new experimental method for panoramic contactless determination of the laminar-turbulent transition position in a three-dimensional boundary layer is described. It is demonstrated that this method allows accurate determination of the transition region boundaries at both reduced and elevated degrees of free-stream turbulence.

A model of the motion of a granular medium is proposed which is based on the elastic interaction of particles, each of which is an absolutely solid body (a disk in the flat case and a ball in the spatial case) of mass m and radius r , surrounded by a sufficiently thin elastic shell. Algorithm for solving the formulated problem is proposed. At each step, the forces and moments of forces arising from the interaction with neighboring particles are calculated. The Cauchy problem for the resulting system of differential equations is numerically solved. Based on the mathematical model, a set of programs has been created that similates the behavior of granular media in moving containers.

A percolation model for the reinforcement of polymer nanocomposites is proposed which allows a quantitative evaluation of the degree of aggregation of nanofillers of arbitrary dimension. When using this model, the efficiency of a nanofiller is determined not by its initial characteristics, but by its ability to generate interfacial regions.

Based on the nonclassical theory of shells, an energy-consistent resolving system of dynamics equations for cylindrical shells made of metal-plastic is obtained as a result of minimization of the total-energy functional of a shell as a three-dimensional body. The numerical method for solving the formulated initial-boundary-value problem is based on an explicit variational-difference scheme. The validity of the method is confirmed by the results of comparison of numerical solutions and experimental data. The ultimate deformability and strength of homogeneous fiberglass cylindrical shells and double-layer metal-plastic shells are anlyzed for various reinforcing structures.

A local strain-stress state in the vicinity of a joint, which arises due to the wavelike structure of this joint, is studied. This thermoelastic problem is solved using a two-scale method.

This paper describes a stress state of membranes of variable thickness at large deformations, namely, the deformation of round continuous anisotropic and isotropic membranes with an initial variable thickness, which are under the action of a uniformly distributed load. It is assumed that the membrane materials are elastic, and generalized Hooke's law is used to describe their behavior. This problem is solved using the equation of equilibrium of the membrane element is used. True principal strains are expressed through dimensionless radial, annular, and normal stresses. An equation is obtained that describes the shape of the membrane after deformation, and the corresponding boundary conditions. Dimensionless stresses and the membrane shape after deformation are determined. Numerical calculations are carried out for various parameters of the problem.

Propagation of a semi-elliptical crack on the suction surface of a rotating blade of a gas turbine compressor is modeled and analysed. The analytical solution for the stress intensity factor (SIF) at the deepest point of the crack shows that the SIF increases with an increase in the crack depth and rotation speed, whereas the SIF decreases with an increase in the semi-elliptical aspect ratio and crack-rotation axis distance. The SIF increase rate with increasing crack depth is found to depend on the aspect ratio. Comparisons of theoretical and numerical calculation results reveal a relative error within 4%. The SIF distribution along the semi-elliptical surface crack front at different depths, positions, and aspect ratios are obtained by a numerical method.

A generator design with a pulse energy of more than 1 MJ connected to an external constant voltage source with limited current strength and power is proposed. The power supply of an active-inductive load is calculated numerically and analytically. Generator parameters for pulse-frequency operation are determined. Results of an experimental study of a small-sized transformer generator are given that confirm the efficiency of this generator and the validity of the method for calculating its characteristics.

This paper describes results of an experimental study of strength characteristics and a microstructure of a permanent joint of dissimilar materials (VT20 titanium alloy and B-1461 aluminum alloy), obtained by laser butt welding. Optical and electron microscopy, the results of X-ray spectral and phase analysis, and the transmission diffraction method with the help of synchrotron radiation are all used to investigate the properties of a welded joint. It is shown that the displacement of laser radiation relative to the contact surface of dissimilar materials significantly changes the microstructure and phase composition of the intermetallic interlayer formed between the materials welded, thereby affecting the strength of dissimilar welded joints.

The issues concerning Scots pine Pinus sylvestris L. seed transfers in northern Europe are discussed. The official rules regulating transfers of Scots pine seeds in the Russian Federation are described. The recent Russian and foreign literature about the geographical variation of main adaptive traits of pine in northern conditions are analyzed. The importance of geographical cultures as main method to study the geographical variation is shown. The differences of limits to transfer in northern Russia and adjacent countries with boreal climate as Sweden and Finland are shown. Based on literature the approach to modeling of seed transfer to survival and height growth of Scots pine plantations are described. The models recently jointly developed in Sweden and Finland are presented and data obtained in the geographical and test cultures of pine for their construction are characterized. The climate parameters used for modeling are briefly specified. The models developed are also valid for genetically improved material. Joint practical recommendations on choosing the optimal source of seeds for reproduction of forests in these two countries are considered. The web tool for optimal choose more suitable material to establish high-productive Scots pine cultures. The official rules regulating Scots pine seed transfers in northern Russia do not fully correspond to patterns of geographical variation of this species. The relevance to develop the seed transfer models for northern Russia and to change seed zoning rules is stressed.

The article presents calculation methodology for evaluating both the technical conditions of the VS-3 mine shaft and the state of rock mass at the Oktyabr’sky mine for the purpose of providing for the safety of mining operations while under-mining rich ores. The proposed method serves as a basis for quantitative and qualitative analysis of the rock mass stress-strain state in the developed areas and inferences about appropriate protective measures for mine workings.

The article deals with the issues related to developing the hardware and software for a tool system for conducting full-scale investigations of the stress-strain state in rock mass. The problem solution using the temperature programming technique for drift compensation and exponential smoothing of signals from strain gauges is discussed. The mathware and software modules allow, during the in-situ rock stress measurements, to observe in real time the process of radial displacements of the measuring well contour while drilling and loading the parallel signaling well, as well as to store the original data in files for their office processing and archiving.

Laboratory tests of the physico-mechanical properties of enclosing rocks of the Botuobinskaya pipe are carried out at PJSC ALROSA in three wells 600 m in depth. The strength characteristics of rocks in thawed and frozen states are estimated. The research results of various lithotypes of rocks are presented and the dependences of their strength characteristics on moisture are found.

Physical modeling was carried out to study deformation processes on plexiglass models with cylindrical cavity under quasistatic loading. Thermal and strain fields were measured during the experiments. The thermal field analysis revealed four regions in the model: two of them are located to the left and to the right of the cavity (those receiving the main load), and two are above and below the cavity. The high temperature values recorded on the lateral surfaces of the cavity indicated their significant deformation. When the applied load was taken off, the model temperature decreased sharply (due to reverse deformation) to the extent that it became lower than the ambient temperature, and then gradually increased.

The extensive seismological data bank for one of the deep mines of the Norilsk-Talnakh polymetallic deposit is analyzed in order to assess the rock-burst hazard of rock massifs. The criterion proposed for this assessment is based on the relation of kinematic characteristics of seismic processes used as migration velocity of reduced center of seismic energy release and apparent rate of aftershocks related to the time of their occurrence for selected major seismic events within the controlled zones of mine field stresses concentration. The minimum value of this parameter characterizes the state of controlled area of the rock mass as rock-burst hazardous. The most significant energy-related seismic events occurring in such time periods result in the rock massif “discharging” the accumulated energy. Then the value of the rock-burst hazard parameter increases, and the controlled area passes into non-hazardous state. Verification of the proposed parameter for assessing the rock-burst hazard, performed for the “Skalisty” mine of the Norilsk polymetallic deposit for the period 2015 - 2017, has demonstrated that the ratio of the kinematic characteristics of seismic processes can serve with a high degree of reliability as a criterion for rock-burst hazard of controlled areas of rock massifs.

An experimental version of the multichannel measuring and computing system Karyer including the measuring complexes Karyer-L and Karyer-T is developed and manufactured. In 2017, the complexes were tested in the continuous monitoring mode at the mine of Zarnitsa diamond pipe. The condition of the “edge - berm” section and the section with a crack were monitored. The monitoring results in the period from 09.07.2017 to 25.09.2017 are presented.

The presented computer program for selecting parameters of hydraulic percussion hammers of single-sided direct and reverse action is based on the tabular data of dimensionless characteristics of hydraulic percussion systems in the space of their basic similarity criteria. The program offers a user the options of setting initial parameters and characteristics of hydraulic percussion systems as their values and possible constrains. The program results in determining all the parameters necessary for a preliminary design of the hydraulic percussion system. The Java-based program has a graphical interface, including menus, toolbar, dialog boxes for input parameters and output tabular data representing the main parameters options, as well hammer head sizes and plotted dynamic characteristics of the working cycles.

The technique of measuring the accelerations generated in the elements of the striker head - tool system is presented when it interacts with the rock mass. The measurements oscillograms and their analysis are shown. The quantitative aspects of the phenomenon are discussed, and an attempt is made to reveal the relationship between the quantitative parameters of impact pulses and fracture results.

A physical model of a hydraulic percussion device is presented, in which the frequency is regulated by a standard flow rate controller, and impact energy - by an original distributor with throttle control, which allows delaying the striker before the start of the reverse phase. A series of experiments is conducted with recording of the characteristics of the work cycles required for the analysis of the system dynamics. Recommendations for possible improvements of the hydraulic percussion device performance are given.