-
Date submitted2021-11-17
-
Date accepted2022-04-06
-
Date published2022-11-10
Method for predicting the stress state of the lining of underground structures of quasi-rectangular and arched forms
- Authors:
- Maksim A. Karasev
- Tien Tai Nguyen
A method for predicting the stress-strain state of the lining of underground structures, the shape of the cross-section of which is different from the circular outline, is considered. The main task of the study is to develop a methodology for assessing the influence of the parameters of the cross-section shape of underground structures on the stress state of the lining. To solve this problem, a method for calculating the stress state of the lining for arched tunnels with a reverse arch and quasi-rectangular forms is substantiated and developed. The methodology was tested, which showed that the accuracy of the prediction of the stress state of the lining is sufficient to perform practical calculations. An algorithm for multivariate analysis of the influence of the cross-sectional shape of underground structures of arched and quasi-rectangular shapes on the stress state of the lining is proposed. Parametric calculations were performed using the developed algorithm and regularities of the formation of the stress state of the lining of underground structures for various engineering and geological conditions, as well as the initial stress state field, were obtained. A quantitative assessment of the influence of geometric parameters of tunnels on their stress-strain state was performed.
-
Date submitted2020-01-10
-
Date accepted2020-01-14
-
Date published2020-02-25
Biogeochemical assessment of soils and plants in industrial, residential and recreational areas of Saint Petersburg
Soils and plants of Saint Petersburg are under the constant technogenic stress caused by human activity in industrial, residential, and recreational landscapes of the city. To assess the transformed landscapes of various functional zones, we studied utility, housing, and park districts with a total area of over 7,000 hectares in the southern part of the city during the summer seasons of 2016-2018. Throughout the fieldwork period, 796 individual pairs of soil and plant samples were collected.A complex of consequent laboratory studies performed in an accredited laboratory allowed the characterization of key biogeochemical patterns of urban regolith specimens and herbage samples of various grasses. Chemical analyses provided information on the concentrations of polluting metals in soils and plants of different land use zones.Data interpretation and calculation of element accumulation factors revealed areas with the most unfavorable environmental conditions. We believe that a high pollution level in southern city districts has led to a significant degree of physical, chemical, and biological degradation of the soil and vegetation cover. As of today, approximately 10 % of the Technosols in the study area have completely lost the ability to biological self-revitalization, which results in ecosystem malfunction and the urgent need for land remediation.
-
Date submitted2015-10-19
-
Date accepted2015-12-27
-
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.
-
Date submitted2015-10-24
-
Date accepted2015-12-17
-
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.
-
Date submitted2009-09-06
-
Date accepted2009-11-10
-
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.
-
Date submitted2009-09-26
-
Date accepted2009-11-21
-
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.
-
Date submitted2008-11-21
-
Date accepted2009-01-03
-
Date published2009-12-11
Financial conglomerates: opportunities for cooperation with mining enterprises
- Authors:
- K. A. Shakhpazov
In this article it is argued whether there are significant opportunities for cooperation between financial conglomerates and the enterprises of the mining industry. The activities of financial conglomerates are not investigated thoroughly yet, as the alliances of that kind are of the relatively recent emergence and are now at the stage of rapid development. Their interactions with other industries have not been deeply researched either. Since the financial conglomerates have major influence on the modern world economical environment, it seems necessary to analyze the probable effect they may trigger in the strategic branch of Russian economy. This theme is particularly interesting nowadays, as the economical crisis demands for the search of new managerial solutions, including the financing sphere.