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Date submitted2023-01-27
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Date accepted2023-03-04
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Date published2023-04-25
Use of the UNIFAC model in the calculation of physicochemical properties of ecotoxicants for technological and ecoanalytical purposes
- Authors:
- Vladimir G. Povarov
- Ignatyi I. Efimov
Modern development vector of environmental monitoring leads to elaboration of analytical methods for qualitative and quantitative analysis of different ecotoxicants. Many studies face the lack of information on isomers and homologues of already studied compounds. This problem cannot always be solved experimentally due to the difficulty of separating or synthesizing certain compounds; the use of group theories of solutions will help partly; using them, solubility in water or partition coefficient between two immiscible solvents is calculated for ecotoxicants. These parameters are important for solving the analytical and ecological problems. The partition coefficient in the octanol – water system is associated with a possibility of accumulation of different compounds in living organisms; the partition coefficient in the hexane – acetonitrile system can be used in gas chromatographic analysis. Solubility in water is closely associated with accumulation of ecotoxicants in water bodies, as well as with their ability to be transferred. This paper presents the capabilities of the UNIFAC model for solving physicochemical problems using the example of calculating the properties of real ecotoxicants on the basis of the available thermodynamic data. All the obtained calculated values were compared with those determined experimentally. In the case of pyrene derivatives, solubility data were obtained for the first time using a correlation group model to calculate the heat of fusion and melting temperature.
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Date submitted2015-12-28
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Date accepted2016-02-28
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Date published2016-12-23
Ion distribution function in their own gas plasma
- Authors:
- A. S. Mustafaev
- V. S. Sukhomlinov
Flat one-sided probe was used for the first time to measure the first seven coefficients in the Legendre polynomial expansion of ion energy and angle distribution functions for He + in He and Ar + in Ar under the conditions when the ion velocity gained along its free run distance is comparable to the average thermal energy of atoms. Analytic solution of the Boltzmann kinetic equation is found for ions in their own gas for arbitrary tension of electric field in plasma when the dominating process is resonant charge exchange. The dependence of cross-section of resonant charge exchange on the relative velocity is accounted for. It is demonstrated that the ion velocity distribution function differs significantly from the Maxwell distribution and is defined by two parameters instead of just one. The results of computational and experimental data agree quite well, provided the spread function of measurement technique is taken into account.
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Date submitted2015-10-19
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Date accepted2015-12-27
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Date published2016-08-22
Key directions in processing carbonaceous rocks
- Authors:
- T. N. Aleksandrova
Mathematical statistics techniques and the data from laboratory mineral and technological studies of samples were used to identify the most common natural and technological associations of microelements in carbonaceous rocks which could be of industrial value if extracted in the form of commercial products. The discovered structures of spheroidal and ring ferrocarbonaceous clusters are respective formations of the class of metal fullerens with expressed magnetic properties. Such clusters may serve as construction blocks for new magnetic structures since each of them is a separate magnetic domain. Extracting such structures and their practical use opens the way to future technologies. It is expected to employ such results in the future in the course of designing new techniques and technologies for benefication of carbonaceous raw materials while developing comprehensively solid mineral resources in the mining industry regions of Russia.
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Date submitted2015-10-24
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Date accepted2015-12-17
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Date published2016-08-22
Spatial distribution of energy release during propagation of fast electron beam in the air
- Authors:
- V. S. Sukhomlinov
- A. S. Mustafaev
The paper focuses on development of the analytical theory to assess spatial distribution of energy released during propagation of the fast electron beam in a gas, in particular in the air at electron energies of 1-100 keV. An approach adopted by authors [2, 3] to study inelastic deceleration of electrons in the air is further developed here. As the inelastic interaction in most cases leads to energy relaxation while elastic interaction causes distribution isotropization over directions, the first task solved in the paper is finding the electron distribution function including only elastic collisions. In the final part of this paper an analytical solution to this task is presented with account of both types of electron deceleration in the air. The calculations show that when elastic collisions are taken into account this leads to increased spatial density of energy release and to narrowing of the primary energy release region of the fast electrons, as compared to calculations accounting for only inelastic deceleration.
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Date submitted2015-07-14
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Date accepted2015-09-28
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Date published2016-02-24
Ion velocity distribution function in arbitrary electric field plasma
- Authors:
- A. S. Mustafaev
- V. S. Sukhomlinov
Experimental investigations of the ion velocity distribution function (IVDF) are of great importance to various kinds of application: plasma nanotechnology, surface treatment, nanoelectronics, etching processes et al. In this paper, we propose a new probe method for diagnostics of anisotropic IVDF. The possibilities of the method have been demonstrated in arbitrary electric field plasma under conditions when an ion acquires a velocity on its mean free path comparable with the average thermal velocity of atoms. The energy and angular dependency of seven IVDF Legendre components for He + in He and Ar + in Ar have been measured and polar diagrams of the ion motion have been plotted. In order to verify the reliability and accuracy of the method the analytic solution of the kinetic Boltzmann equation for ions in plasma of their own gas has been found. Conditions under which resonant charge exchange is the dominant process and the ambipolar field is arbitrary have been considered. For the ambipolar field the dependence of resonant charge cross-section on the relative velocity has been taken into account. It is shown that the form of the IVDF is significantly different from the Maxwellian distribution and defined by two parameters. The results of theoretical and experimental data taking into account the instrumental function of the probe method are in good agreement. Calculations of the drift velocity of Hg + ions in Hg, He + in He, Ar + in Ar, and mobility of N 2 + in N 2 are well matched with known experimental data in wide range of electric field values.
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Date submitted2014-10-15
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Date accepted2014-12-30
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Date published2015-08-25
Method of controlling the temperature field on the basis of the Green's function
- Authors:
- Yu. V. Ilyushin
- I. M. Pershin
At the present stage of development of automatic control systems raises the question of maintaining the set temperature objects. The authors developed MetO-wild synthesis of nonlinear regulators to stabilize the temperature field, a uniform object of management on the basis of a given error. We obtained a function of the initial heating and the mathematical modeling of the process, analyzed the results. By creating a regulator there has been designed software and hardware programming language Pascal, which allows to simulate the behavior of temperature fields in an isotropic web. It is a simulation of the temperature of the system in different configurations: with different amounts of pulsed heating sources with relay control principle. Practical results of the research suggest the possibility of constructing silicon carbide heating element made in the form of an isotropic core.
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Date submitted2009-09-06
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Date accepted2009-11-10
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Date published2010-06-25
Diagnostic method for measurements of emission parameters of thermoemission cathodes
- Authors:
- A. S. Mustafaev
This article deals with the diagnostic method of emission parameters of thermo emission cathodes by the transverse magnetic field. The knudsen Cs-Ba-diode with the surface ionization are investigated.
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Date submitted2009-09-26
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Date accepted2009-11-21
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Date published2010-06-25
The measurements of emission parameters of tungsten thermo cathodes in plasma energetic equipments
Emission parameters and coefficients of reflection of heat electrons from tungsten thermo cathodes were investigated under nontraditional for emission electronic conditions, when the surface contacts with highly ionized plasma. For measurements plasma diode electron current-magnetic field strength relations were used. Parameter Dj, which characterizes cathode heterogeneity by work function, and coefficient of reflection for policrystallic tungsten and for face 110 tungsten single crystal were measured. Proportion entering in effective reflection coefficient of electrons, reflected immediately from the surface and from potential barrier of spots field was determinate.
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Date submitted2009-08-13
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Date accepted2009-10-29
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Date published2010-02-01
Analysis of statistical data of lecture of the alloyed steels
- Authors:
- R. V. Kurtenkov
Influence of a chemical compound on the carbon contents in a steel is analysed, in the course of processing of month basic data the mathematical model is received, it is offered optimum significances of source parametres at the carbon contents in a steel.
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Date submitted2009-07-18
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Date accepted2009-09-30
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Date published2010-04-22
Account of stress gradients in rock mass in designing of mining constructions
- Authors:
- S. V. Suknyov
- M. D. Novopashin
Using the gradient approach the criteria of shear and tensile cracking are developed in compression under conditions of stress concentrations near mine workings. Considering the size effect, a function type of local strength is determined, expressions for critical pressure are derived and comparison between analytical and experimental data is performed.