Home – Home – Jornals – Atmospheric and Oceanic Optics 2020 number 7

The absorption spectra of carbon dioxide confined in aerogel sample with pore sizes of 60 nm have been recorded at a room temperature in the 2250-2400 cm^-1 region using a Bruker IFS 125HR FTIR spectrometer. Parameters of spectral lines of CO₂ are derived; their dependence on rotational quantum numbers are shown. The results are compared with data available in literature.

Lidar observations at Siberian Lidar Station (SLS) of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences in Tomsk (56.5°N; 85.0°E) showed the presence of stratospheric aerosol layers over Tomsk during winter 2017-2018, signs of descending air masses, and deficit of ozone. Aura OMI/MLS observations indicated that in December-January 2017/2018 the total ozone (TO) content and NO₂ content in the stratosphere over the Northern Eurasia, as well as the temperature in the stratosphere, were significantly lower than normal. Analysis of back trajectories and integrated (over profile) TO showed that the dynamic disturbance of the Arctic stratosphere in December 2017 led to extrusion of cold air masses with excessive reactive chlorine (in view of NO₂ deficit) beyond the Arctic circle and their intrusion into the stratosphere of Tomsk. Seemingly, in the Tomsk stratosphere they were exposed to solar radiation and, staying chemically isolated, evolved into chemically disturbed state, similar to the state of springtime Arctic stratosphere, where ozone is intensely destroyed until the final warming.

The special features of hydrooptical signals of an airborne polarization lidar are theoretically and experimentally analyzed in the case of sensing of homogeneous water mass under controllable conditions. The results obtained expand the possibilities of interpretation of lidar return signals, especially in complex and ambiguous situations. Results of theoretical and experimental investigations of the depth profiles of hydrooptical signals of airborne polarization lidars operated under conditions of homogeneous water depth are presented.

This review is devoted to the analysis of the history and current trends in the development of the velocimetry method based on particle images for an aerodynamic experiment. The authors consider the basics of the method, various implementations, former and current status of equipment. Special attention is paid to the methods of data processing and evaluation of various physical values in the flow from the measured velocity fields. The paper briefly analyzes some optical methods that can be used together with velocimetry based on particle images and are implemented using similar equipment. The main focus of the review is set on the works that demonstrate the potential and the current level of the anemometry method based on particle images in the context of an aerodynamic experiment.

The present work is devoted to the experimental study of a high-speed jet exhausting from a model dual-stream jet nozzle which was performed using non-contact (shadow visualization) and probing (Pitot pressure tube) methods for measuring gas-dynamic parameters. Azimuthal non-uniformity of the pressure distribution, whose magnitude in the external duct is much higher than that in the internal one, is revealed. The cause for the formation of the 3D flow structure is related to the supporting pylons installed inside the nozzle contours and with the formation of a transonic flow mode in the external duct.

Stability of the laminar boundary layer on the surface of a hypersonic nozzle for the Mach number M = 6 of the Transit-M wind tunnel is calculated. The laminar boundary-layer profiles are obtained by solving the Navier-Stokes equations numerically within the framework of the Ansys Fluent software. N -factors of the Goertler vortices and of the first and second Mack modes are obtained in the approximation of the linear stability theory. It is demonstrated that the Goertler vortices are the most unstable disturbances for the nozzle under consideration. Empirical dependences of the local Reynolds number of the laminar-turbulent transition on the N -factor and unit Reynolds number are determined.

This work investigates the turbulent flow in a channel roughened by seven ribs of rectangular cross section disposed transversely. The flow configurations of identical ribs from the first one generate a large eddy spreading along the top of the two first ribs, trapping the flow of the first cavity. The widening of the first rib may solve this problem. Therefore, this flow configuration might be required in building structure applications necessitating regular structures from the first cavity. Streamlines contours indicates that the first rib behaves as a forward facing step when L₁ > 5h (L₁ is the first rib width), regular structures of the flow occurs from the first cavity. The effect of wider first rib is highlighted by friction and pressure coefficients profiles and those of the turbulent kinetic energy. Its effect also appears in the Darcy friction factor. The viscous and pressure forces applied on the first rib and the 5th pitch roughness indicate that the pressure force is dominant. Darcy friction factor characterizing the flow and pressure drag coefficient evaluated at the 5th pitch roughness remains independent of Reynolds number, while the drag force applied on the first rib increases when Reynolds number augments.

Results on flight dynamics of an axisymmetric vehicle with a control action in the form of gas jet ejection are reported. The differences in the flight trajectories with and without allowance for the pressure redistribution over the vehicle surface due to transverse gas jet ejection are considered and analyzed. Targeted software is developed on the basis of the equations of motion of a material point in space and rotation of the flying vehicle around its center of mass. The influence of the pressure redistribution over the axisymmetric vehicle surface owing to ejection of a lateral transverse gas jet on the flight trajectory and on the rate of vehicle deviation in terms of the yaw angle is demonstrated.

Deformations of a compliant coating in a turbulent flow, measured previously and calculated in this work, are compared. The calculated spectral density of coating deformations at low frequencies (25-250 Hz) turned out to be almost two orders of magnitude higher than the measured one, and the rms value of the measured deformation was seven times lower than the calculated one. The transitional regime for stabilizing the forced coating oscillations under the action of a pressure wave is calculated. It is shown that the coating almost always works in the transition regime, without reaching the maximum deformation amplitudes that are characteristic of the steady state. It is concluded that it is necessary to use more complex boundary conditions that take into account the non-stationary character of the process because the amplitude of coating deformation varies in a complex way during the lifetime of organized structures moving in a turbulent boundary layer.

A method of direct numerical simulation and a method of solving the boundary-layer equations were applied to parameters of a supersonic boundary layer for a flow past a flat plate (Mach number M = 2) for the case of a plate coated with a sublimation material. The sublimating material is naphthalene (C₁₀ H₈). Comparison of results from these two approaches ¾ numerical simulation and solution of a boundary layer under the assumption on the local self-similarity ¾ demonstrated a satisfactory agreement between them. Calculations demonstrated that a higher surface temperature produces a higher mass rate of evaporation. Meanwhile, the total heat flux to the solid wall decreases and the wall temperature is lower than for the case of zero sublimation. Since the molecular mass of naphthalene is by several times higher than the molecular mass of air and due to evaporation-induced wall cooling, we observe a higher density of the mixture of air with the sublimating substance vapor near the wall. This may facilitate a higher stability of the supersonic boundary layer and delays the flow transition to the turbulent state.

The paper analyzes the complex topology of swirling flows generated in the cylinder by its rotating end face. Using the flow visualization for different parameters of swirl of the upper end of the cylinder, the general laws of the evolution of the region with a counter flow (bubble-like vortex decay) are shown regardless of the contact of the studied vortex flow with various liquids or gas at the free end. The research has found for the first time that the scenario for the appearance of the bubble-like breakdown region depends weakly on the properties of the medium that restricts the circulation of the working fluid, but differs significantly from the dynamics of vortex flows limited by the “solid” second wall - the fixed end of the cylinder. For example, during the axial vortex breakdown, the modes of stationary vortex motion with the appearance of the recirculation zone contact with the interface surface of two media have been revealed, which is not typical for closed flows. The results obtained are of interest for further development of vortex devices and reactors that provide complex vortex motion of ingredients for mass transfer intensification, both in terms of optimizing the operation of existing setups and for designing new devices.

The study is about developing a gasdynamic model of motion of multispeed continua for the case of nozzles with complex geometry. These nozzles imitate the shape of a two-stage confusor-shaped dust cleaner. The paper studied the influence of force interaction between the gas phase and solid phase in the flow duct of the nozzle; this effect was studied for a wide range of input flow parameters. A special focus was on the regimes of gas-solid flows through curved channels for the case of high loads of solids at the nozzle inlet. A mathematical model was developed that takes into account the impact from the wall-bounced particles upon the distributions of gas phase and solid phase for the entire region. It was shown that account for particle bouncing produces an extremum in solids concentration distribution in the flow duct of the separator.

The heat transfer from a single sphere suspended in a cylindrical channel with finely dispersed air-water (aerosol) flow is experimentally studied. Under stationary heating conditions, the values of the heat-transfer coefficients are obtained as dependent on the Reynolds number and the water mist rate. A physical model of heat transfer from the sphere surface with water mist-air flow is proposed, which allows evaluating the processes proceeding at the various stages of droplet evaporation in the flow near a heated surface and formation of a water film on the surface itself. The relative mass of the droplet moisture deposited on the sphere surface is estimated depending on the water mist rate and Reynolds number of the flow. A criterial equation is obtained that generalizes the experimental data in the form of the dependence of Nusselt number on the regime parameters of Reynolds, Weber, and the water-to-steam phase transition parameter is obtained.

The dynamics of evaporation from the confined surface of a horizontal layer of liquid (ethanol) under the action of a gas (air) flow has been experimentally studied. The influence of the longitudinal dimension of the interface (0.01-0.03 m) on the specific mass rate of evaporation was studied. It was found that the specific mass evaporation rate decreases with an increase in the interface length due to a decrease in the vapor concentration gradient in the boundary layer.

In the framework of the thermal energy scheme, the growth of a vapor bubble in a uniformly superheated liquid is simulated numerically. The results of numerical calculations are in good agreement with the solution of [3] in a wide range of Jacob numbers. The account for the interfacial surface permeability at high values of Stefan number shows a good match with the results of numerical calculations.

The paper offers a numerical simulation of the heat state for a two-layer semitransparent medium that imitates a hypothetical snow cover upon an opaque semi-infinite substrate; the layers of cover have different absorption and scattering coefficients. Computations were performed for key parameters typical of winter season. It was shown that, depending on the optical thickness of every layer and proportions of absorption to scattering in the incident radiation, we observe more intense heating of near-surface or deeper zones in the snow-ice medium. The radiation part of problem was solved using a modified average-flux method used to take into account the dependency of optical properties on the wavelength of incident radiation, scattering, and reflectance at the layers boundaries.

The laser-pulse method was used to measure the thermal diffusivity of La_98.8Fe_1.2 alloy in the temperature range of 293-1623 K of the solid and liquid states, including the regions of phase transformations. The measurement uncertainties of the heat transfer coefficients were ± (3-6) %. Approximating equations and tables of reference data on thermal conductivity and thermal diffusivity of La_98.8Fe_1.2 alloy have been obtained for scientific and practical use. A comparison of measurement results with known literature data on thermal diffusivity of pure lanthanum has been carried out.

The effect of mechanically activated coal grinding on the time of their ignition in a vertical tubular reactor is studied experimentally and numerically. The experiments showed that coal, ground by an activator mill (disintegrator mill), ignites faster due to the effect of mechanical activation. According to numerical calculation of the processes of ignition and combustion of mechanically activated pulverized coal fuel, it is clear that the use of non-stationary methods for turbulence simulation and a model of the volatile yield, taking into account the structure of coal matter, allow an estimate of the contribution of mechanically activated grinding to the intensity of devolatilization.

This work deals with the experimental study of transient flow regimes occurring in the laboratory model of a hydraulic turbine draft tube at a change in the control parameters of setup. The transition from the partial load regime, when a precessing vortex core is formed, to the best efficiency point without a core is considered. To set accurately the speed of runner rotation and the flow rate of the working medium, the setup was controlled by special software. To ensure accurate multiple reproduction of a given transition cycle between two regimes, the control program has been upgraded. Using a specially developed procedure of phase averaging of a laser Doppler anemometer (LDA) signal recorded during multiple repetitions of transient regimes, the velocity profiles were obtained for different phases of changing the setup operating conditions.

The problem is considered on a periodical of time motion of a viscous liquid bordering on a solid body and a gas. The liquid is affected by oscillatory influences which have no predominant direction in space. The new hydro-mechanical effect is revealed which consists in that the free parts of the hydro-mechanical system - liquid layers - perform unidirectional stationary rotational motion with the background of oscillations.

Many industrial combustion devices rely on jet flame combustion in the crossflow to achieve mixing and reaction. Previous research offers a limited predictive capability regarding the coupling effects of the crossflow and jet flow on the flame radiative fraction. In this work, a new theoretical equation is derived to relate the radiative fraction to the fuel flow rate and the crossflow velocity. The experimental results show that the flame length increases as the crossflow velocity increases for all considered flames. The results of this work suggest that the stretching factor is 0.08 s. The radiative fraction is almost independent of the nozzle diameter in the case of a low crossflow velocity. The crossflow has the strongest effect on the radiative fraction for a smaller nozzle diameter. This is because of the effect of the crossflow and jet flow velocities on the soot residence time, which is proportional to the radiative fraction.

If a Li-ion cell fails and the electrolyte leaks out into air, a flammable premixed gas cloud may be formed. The electrolyte combustion energy is 65 ÷ 70 % of the total energy content of the cell. The main objective of this study is to determine the laminar burning velocity and the Markstein length for dimethyl carbonate and propane in a 20-liter explosion sphere with initial conditions at 100 kPa and 300 K. Five different stretch extrapolation models for the laminar burning velocity give practically the same result. The experimental results agree well with the previously published data and are slightly lower than the theoretical predictions. The laminar burning velocity for dimethyl carbonate is measured close to the saturation point under the initial conditions, which has not been previously reported.

The dynamics of the formation and extinction of laminar diffusion flames of methane and ethylene formed in an oxidizing medium in zero gravity above the surface of a flat porous burner have been studied numerically. The calculations reproduce the conditions of experiments carried out within the framework of the BRE-Flamenco project of the Advanced Combustion Microgravity Experiment (ACME) program aimed at the study of combustion in zero gravity. A three-dimensional non-stationary model taking into account multistep and multicomponent chemical mechanisms of oxidation of fuels, soot formation and oxidation, and the thermal radiation of combustion products was tested for jet laminar diffusion flame of methane under normal gravity and for ethylene flame inder short-term zero gravity in free fall in the test tower. Calculations for flames formed under long-term zero gravity were performed for the range of fuel consumption typical of combustion of solid and liquid combustible materials. In all cases considered, combustion proceeds in an unsteady mode, despite the constant fuel consumption. The flame growth stage is accompanied by a continuous decrease in temperature in the reaction zone due to heat loss by radiation followed by local extinction and pulsations of the flame and the complete cessation of combustion. The effect of the type and fuel consumption on the duration of the flame and the dynamics of its decay is analyzed. The sensitivity of the calculation results to the chemical mechanism is found. It is established that the proportion of energy emitted by the flame in zero gravity is an order of magnitude higher than that for the flame under normal gravity. Radiant heat loss are shown to cause instability and extinction of the flame.

Fluorinated ethylene propylene (FEP) wire insulation ignition is investigated in a forced flow field in microgravity and normal gravity with a continuous current. First, FEP insulation melts and decomposes, causing jet bursting in both normal gravity and microgravity. Second, the forced flow and gravity produce minor effects on the core heating and bursting time, while the pyrolysis time increases slightly with increasing air velocity. Third, the positively stretch rates in terms of the velocity gradients are higher in microgravity. Both the forced flow and gravity have significant effects on the induction time, which is dependent on the stretch rate and Damköhler number. The induction time increases with increasing air velocity, and it is higher in microgravity. Finally, the ignition delay time is dominated by the core heating and bursting time, while its bigger value and faster increase in microgravity with increasing air velocity are dominated by the induction time.

The flame propagation behavior and the effect of particle agglomeration are examined by changing the size of PMMA particles in laboratory-scale experiments. PMMA particles having a very narrow size distribution are used. We show that the minimum explosible concentration increases as the particle size decreases. On the other hand, the flame propagation velocity also increases as the particle size decreases. Therefore, the minimum explosible concentration and the flame propagation velocity show the opposite dependences on the particle size. It is considered that the minimum explosible concentration is strongly affected by the interparticle distance; meanwhile, the flame propagation velocity strongly depends on the specific surface area. It has to be emphasized that the severity of the explosion can be serious for very fine particles, although the minimum explosible concentration is fairly high.

Non-combustible solid materials play a major role as inerting agents in explosion prevention. While the importance and application of these materials are well understood, there is still a lack of information about the actual mechanisms responsible for explosion suppression. Especially, the role of inert materials with a large specific surface area and the influence of the moisture content of inert materials have not been sufficiently investigated. In this work, an experimental and computational study of the effects of inert materials on ignition and flame propagation in lycopodium-air mixtures is undertaken. The influence of a large specific surface area is studied by using Clinoptilolith as an inert material.

Thanks to its mesoscopic kinetic nature, the discrete Boltzmann method has a capability of investigating unsteady detonation with essential hydrodynamic and thermodynamic nonequilibrium effects. In this work, an efficient and precise reactive discrete Boltzmann method is employed to investigate the impact of the amplitude and wave length of the initial perturbation, as well as of the chemical heat on the evolution of unsteady detonation with nonequilibrium effects. It is shown that the initial perturbation amplitude only affects the unsteady detonation in the early period, and the detonation becomes self-similar with minor phase differences later on. For small wave lengths, the pressure increases faster with a higher oscillation frequency in the early period, but decreases soon afterwards. With increasing chemical heat release, the pressure and its oscillations increase, and the nonequilibrium effects become more pronounced, but the oscillatory period decreases. When the wave length or chemical heat release is small enough, there is no transverse wave or cellular pattern, and the two-dimensional unsteady detonation reduces to the one-dimensional case.

Rapid phase transitions occurring with a sharp increase in a specific volume can be accompanied by explosive gas-dynamic phenomena. A model is presented for calculating shock waves generated in the atmosphere during an explosion of a liquid gas pressure reservoir, based on the assumption of a thermodynamically equilibrium state of a vapor-liquid mixture in which both vapor and liquid have equal velocities and are in a state of saturation at local pressure. The spherically symmetric scattering of a boiling liquid cloud is calculated, pressure profiles under various initial conditions are compared, and the primary shock wave parameters are validated according to the results of available experimental data. Two-dimensional calculations of shock waves during the fracture of a cylindrical tank near the underlying surface at various degrees of filling are presented.

This paper is devoted to the study of the nature of the synergistic effect in flames of methane- and formaldehyde-air mixtures. Combustion of mixtures of various fuels is of great practical and fundamental interest. It is found that the addition of formaldehyde to a rich methane/air flame at a constant concentration of methane first reduces its propagation speed and then begins to increase it. The synergism mechanism in this case is due to the predominant and complete formaldehyde consumption due to its greater reactivity and its negative impact on the rate of methane consumption. As a result of predominant combustion of one of the fuels, there are two spatially separated heat release zones in the flame. Heat release in the first the zone is mainly due to the oxidation of formaldehyde and formyl radical, and in the second zone to in the recombination of methyl radicals. An analysis of the flame speed sensitivity shows that the key reactions affecting the flame speed are the stages of formation of radicals (mainly hydroxyl) or products that lead to their formation. Reactions that make the main contribution to heat release generally do not affect the flame speed. It is found that the interaction of two fuels CH₄ and CH₂O in the mixture with air leads to a marked increase in the super-adiabatic temperature effect.

The standard enthalpies of formation of 1,1-bis(methoxy-NNO-azoxy)-3-nitro-3-azabutane and 1,1,8,8-tetrakis (methoxy-NNO-azoxy)-3,6-dinitro-3,6-diazaoctane were experimentally determined to be 87.7 ± 3.9 and 283.8 ± 6.2 kJ/mol, respectively. Calculations have shown that solid composite propellants containing these two compounds as gasifying components in metal-free compositions based on an active binder and ammonium perchlorate are inferior in the highest achievable effective impulse at the third stage of the rocket system I_ef(3) to compositions based on HMX, but in designing special compositions with a limited content of organic explosive (not higher than 30 ÷ 35 %), these two compounds provide 5-10 s higher values of I_ef (3) than when using HMX.

Mathematical modeling of combustion of micron-sized and nanometer boron particles in air with allowance for changes in the heat and mass transfer mechanism and a decreasing particle size is carried out. The Knudsen number is taken as an indicator of the transition from one regime to another: a continuous medium assumption is valid for describing the heat and mass transfer mechanisms in the case where Kn < 0.01, the free molecular regime takes place for Kn > 10, and a transition regime is realized for 0.01 < Kn < 10. Particle sizes at which different types of heat and mass transfer occurs with respect to boron combustion in air at pressures of 0.1 ÷ 4 MPa are estimated. The time it takes for boron particles to combust within the framework of the assumption of a continuous medium and in a free molecular mode is determined. It is shown that calculation models for determining the burning time of boron particles with initial sizes close to micron-sized and nanodispersed ones should take into account a change in the heat and mass transfer mechanism with variation in the current particle radius during burnout.

A microwave diagnostics method and radio interferometers with wavelengths of 3.2 and 2.1 mm are used to study the kinematic and electrophysical characteristics of shock-compressed argon plasma, which is initially at atmospheric pressure. This research study is carried out at pressures of 12 ÷ 56 MPa, shock wave velocities of 3.1 ÷ 6.2 km/s, temperatures 9 000 ÷ 19 000 K, and densities 0.006 ÷ 0.012 g/cm³ for powers of Coulomb nonideality from 10^-4 to 0.2. The data obtained on the shock-wave compressibility of argon are consistent with the known measurement results and calculations using the modified Van der Waals model and the chemical plasma model. A set of values of the reflection coefficient of electromagnetic radiation from the shock wave front at wavelengths of 3.2 and 2.1 mm is obtained, which serves as a basis for estimating the conductivity and electron concentration behind the shock wave front. The experimental data are consistent with calculation results in a wave velocity range of 3.1 ÷ 3.6 km/s. It is established that with a further increase in the velocity has no effect on the reflection coefficient.

This study presents a review of high-velocity projection methods and devices intended for the experimental study of the protection of equipment and structures from a high-velocity impact by compact elements, particularly protecting spacecrafts from collision with natural meteorite particles. Explosive projectors used in experiments to test protective structures at high impact velocities are shown. The results of numerical and experimental studies of these schemes are presented.

The article presents a case-study of mathematical modeling of electromagnetic and electromechanical processes in a downhole vibration exciter EM drive. The authors propose the mathematical model of EM drive on the basis of a double-acting EM machine. This model maintains a wide-range analysis of transient and quasi-stable operating regimes. The algorithm and implementation of the model using the structural modeling methods and means in the Matlab Simulink environment are described. The model verification is carried out by means of comparison of the simulation and physical models of EM drive within the configuration of downhole pulse vibration exciter. The appropriateness of the model is proved. The authors give recommendations on further improvement of the model and its accuracy in calculation of dynamic behavior of drives.

The studies into the mechanism of activation of sphalerite flotation by ions of heavy metals show that neither ion exchange nor electrochemistry explain the experimental facts, namely, activation of flotation of copper mineral by lead ions, activation of sphalerite flotation by zinc, or flotation in the presence of non-conducting surface layer with silver or mercury. The authors put forward the hypothesis of activation due to the effect of physisorption of a collector in elementary event of flotation. It is possible to activate froth flotation by the products of nonstoichiometric interaction between xanthogen and ions of some heavy metals. The influence of the scope of deviation from the stoichiometric relation of concentrations of xanthogen and activation metal salt on the collectability of the interaction products is described. The activation efficiency of the interaction products is estimated using the criterion of ‘surface flow thickness’ of the film of collector derivatives at the gas-liquid interface.

The article addresses processability of old copper-zinc ore flotation tailings. Potential reserves and processability of mining waste are considered in terms of Uchaly Mining and Processing Plant. The mineral composition and chemistry of old tailings are determined. The analysis of modes of interaction between gold and tailings minerals reveals inefficiency of conventional technologies in extraction of valuable components. The authors validate thermochemical processing technology for old tailings with gold and silver recovery using chlorammonium reagents. The thermal study determines the mode of thermochemical interaction of old flotation tailings with NH₄Cl and NH₄Cl - NH₄NO₃ mixture, efficient sequence of tailings processing with chlorammonium reagents and the optimum temperature ranges.

The physicochemical analysis of distribution of useful components in processing of ash and slag of the thermal energy sector plants is performed. The article describes thermodynamics and kinetics of chemical reactions during agglomeration of feedstock and ammonium hydrofluoride at the temperatures of 50-200 °С, sublimation of ammonium hexafluorosilicate in the temperature range of 350-550 °С, production of amorphous silica nanoparticles, alumina particles and red iron oxide pigment, as well as formation of calcium fluoride (Ca, Y)F₂ which is a concentrator of rare and other elements. The efficient technology is developed for processing of electromagnetic fraction of ash and slag with integrated recovery of various useful components.

The article considers extraction of rare elements from monazite and their leaching. In this study, phosphate decomposition process was conducted using alkaline roasting. The results showed that the phosphate decomposition of monazite from Bangka Island increased with increasing temperature and increasing monazite/NaOH mass ratio. Analysis of the decomposition rate on the basis of shrinking core model revealed that the rate could be appropriately expressed by the equation based on mixed control of diffusion through a residual layer and surface chemical reaction.

The author gives methodological ground for the assessment of ecological stability of the mining industry areas based on the mechanism of interaction between the natural and technical subsystems. The list and values of the required ecological stability indicators are presented for the environmental risk classification of industrial facilities.

This study discusses the importance of phreatic layer in the stability of slopes. It describes the development of phreatic layer based on Dupuit and Forcheimmer assumptions in the slope. To understand the water flow behavior through slopes, design of prototype was prepared and later the set-up was fabricated in the laboratory. The set-up includes simulated conventional dump made up of soil type material. The design of experimental set-up resembles the actual scenarios of overburden dumps constructed over the bases having inclination varying from 0º to 5º. The phreatic surfaces obtained in physical models are further compared with numerical models prepared using SEEP/W software.