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Date submitted2023-07-27
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Date accepted2024-06-03
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Date published2024-12-25
Normalized impulse response testing in underground constructions monitoring
Impulse Response testing is a widespread geophysical technique of monolithic plate-like structures (foundation slabs, tunnel lining, and supports for vertical, inclined and horizontal mine shafts, retaining walls) contact state and grouting quality evaluation. Novel approach to data processing based on normalized response attributes analysis is presented. It is proposed to use the energy of the normalized signal calculated in the time domain and the normalized spectrum area and the average-weighted frequency calculated in the frequency domain as informative parameters of the signal. The proposed technique allows users a rapid and robust evaluation of underground structure’s grouting or contact state quality. The advantage of this approach is the possibility of using geophysical equipment designed for low strain impact testing of piles length and integrity to collect data. Experimental study has been carried out on the application of the technique in examining a tunnel lining physical model with a known position of the loose contact area. As examples of the application of the methodology, the results of the several monolitic structures of operating municipal and transport infrastructure underground structures survey are presented. The applicability of the technique for examining the grouting of the tunnel lining and the control of injection under the foundation slabs is confirmed. For data interpretation the modified three-sigma criteria and the joint analysis of the attribute’s behavior were successfully used. The features of the field work methodology, data collection and analysis are discussed in detail. Approaches to the techniques' development and its application in the framework of underground constructions monitoring are outlined. The issues arising during acoustic examination of reinforced concrete plate-like structures are outlined.
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Date submitted2024-01-31
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Date accepted2024-06-03
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Date published2024-07-04
Rationale for a possibility of using humic preparations production waste for wastewater purification from metals (Cd2+, Zn2+, Mg2+, Cu2+) aimed at developing efficient measures on environmental rehabilitation
Results of studying optimal conditions and parameters for afterpurification of underspoil waters from metal ions using humic acids production waste are presented with a view to develop the efficient measures on environmental rehabilitation of ecosystems disturbed by the development of copper pyrite deposits. The influence of contact time and waste dosage on the purification process was analysed, changes in the pH of wastewater and its impact on the growth and development of plants were studied. The key factors were identified allowing to achieve the efficiency of the purification process – the optimal contact time in the range from 120 to 180 min and waste dosage of 10 g/l. The study showed that the use of waste resulted in a neutral pH value of 7.03 compared to the initial pH value of 5.95. It was ascertained that the use of iron-magnesium production waste in combination with waste from humic preparations production made it possible to achieve the MPC of commercial fishing importance (with the exception of magnesium). Wastewater after the afterpurification process with high magnesium concentrations did not have a stimulating effect on the growth and development of Lepidium sativum L. plants. From biotesting results it can also be stated that there is no negative impact on the growth and development of Lepidium sativum L. The results obtained indicate a potentiality of using afterpurified wastewater for watering plants in the process of initiating the environmental rehabilitation of the disturbed ecosystems.
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Date submitted2021-04-30
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Date accepted2021-11-30
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Date published2021-12-27
Methodology for testing pipeline steels for resistance to grooving corrosion
- Authors:
- Viktor I. Bolobov
- Grigoriy G. Popov
The methodology for testing pipeline steels is suggested on the assumption that for the destruction of pipes in field oil pipelines by the mechanism of grooving corrosion the simultaneous fulfillment of such conditions as the occurrence of scratches on the lower generatrix of the pipe, eventually growing into a channel in the form of a groove, emulsion enrichment with oxygen, presence of pipe wall metal in a stressed state, presence of chlorine-ion in the oil-water emulsion is required. Tests are suggested to be carried out in 3 % aqueous solution of NaCl with continuous aeration by air on bent plates 150×15×3 mm, made of the analyzed steel, the middle part of which is under the action of residual stresses σ res , close to the level of maximum equivalent stresses σ eqv in the wall of the oil pipeline, with the presence of a cut on this part on the inner side of the plate as an initiator of additional mechanical stresses. Using the value of the modulus of normal elasticity of the analyzed steel, the degree of residual strain of the elastic-plastic body from this material, corresponding to the value σ res ≈ σ eqv is calculated, based on which the plates are bent to the required deflection angle, after which the cut is applied to them. After keeping the plates in the corrosive medium for each of them the increase in depth of the cut as a result of corrosion of the walls by the corrosive medium is analyzed, from which the rate of steel K by the mechanism of grooving corrosion is calculated taking into account the duration of tests. Corrosion rate values for two pipe steel grades determined by the suggested procedure are given. The comparison of K values obtained leads to the conclusion about the higher resistance to grooving corrosion of 09G2S steel.
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Date submitted2017-11-17
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Date accepted2018-01-05
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Date published2018-04-24
Estimation of the relation of strength and ultrasound speed in glass-reinforce plastic
- Authors:
- A. I. Potapov
In mining machinery, details and products made of composite materials are widely used, especially from GRP (glass-reinforce plastic). The work evaluates the relationship between the strength and the speed of ultrasound for nondestructive testing of strength in an article made of composite materials such as GDR with the use of a pulsed ultrasonic method. Methods for estimating the connection, the method of mechanical compression tests and mathematical processing and establishing the relationship between the ultrasonic velocity and the strength of GRP are considered. The results of experimental studies on establishing the relationship between the strength of GRP on compression and the speed of longitudinal ultrasonic waves are presented. As a result of statistical processing of the experimental results, equations of the relationship between the compressive strength and the ultrasonic velocity in fiberglass are obtained.
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Date submitted2014-11-29
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Date accepted2015-01-09
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Date published2015-10-26
G.V.Bogomolov and his role in development of national hydrogeology
- Authors:
- D. L. Ustyugov
- L. P. Norova
In March 2015 the scientific community celebrated the 110th anniversary of the birth of one of the founders of the hydrogeological and engineering-geological school, an honouree of State Award of the USSR and the Byelorussian SSR, Academician Gerasim Vasilyevich Bogomolov. The article is devoted to several important stages of the development of Russian hydrogeology, which are primarily associated with the research conducted by G.V.Bogomolov. His role in the development of hydrogeology in Belarus, i.e. theory and practice of the use of groundwater, is emphasized. This article is about the man who was a brilliant geologist, scholar, lecturer and an outstanding research manager. G.V.Bogomolov founded a school of disciples and followers who continued to develop and put into practice the academician’s ideas in various branches of geological theory and practice.
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Date submitted2009-09-27
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Date accepted2009-11-28
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Date published2010-06-25
Fighting school habits
- Authors:
- A. B. Zhdanov
The article deals with some problems which occur when teaching English to first- and second-year students. The psychological reasons of those are considered from the viewpoint of Russian history, as well as shortcomings of the modern school system. Testing is regarded as a way to solve the problems specified.
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Date submitted2009-09-17
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Date accepted2009-11-07
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Date published2010-06-25
Test as the form of the economics departments students final knowledge checking at studying the discipline «Business russian as the foreign language»
- Authors:
- E. A. Kolesova
The problems, appearing when compiling test materials for the students-foreigners of the economic professions, studying sphere of business communication, are analyzed in this article. The types of mistakes, allowed students in process of the performing the checking tasks, are systematized. It is offered the examples of the exercises, presented in test.
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Date submitted2009-09-16
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Date accepted2009-11-17
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Date published2010-06-25
Information technology usage during linguistic competitions in technical higher school conducting
- Authors:
- E. V. Terentyeva
This article is devoted to the issue of IT technologies usage for teaching methods in humanities. The article is covering the experience of carrying out the linguistic creative contest among the students of the Mining Institute with the help of the soft «My test». Advantages and disadvantages of the mentioned programme for such kind of workshop are noted in the article. The conclusion for improving of teaching methods with the help of IT technologies is made.
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Date submitted2009-07-27
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Date accepted2009-09-15
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Date published2010-04-22
Geomechanical problems in the forecast of stress-strain state of underground stations of the metro at a great depth
- Authors:
- P. A. Demenkov
- I. E. Dolgiy
- V. I. Ochkurov
Forecast of stress and strain state of deep underground metro stations is considered in this article. A complex approach to study of static work of the metro stations including the in situ testing at different stages of their construction and numerical modeling with finite element method is shown.
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Date submitted1950-07-21
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Date accepted1950-09-18
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Date published1951-04-30
Testing the electric motors with new moisture-resistant insulation of submersible motor-pumps with a capacity of Q = 30 m3/hour
- Authors:
- L. F. Shklyarskii
The present work is the result of creative collaboration of the Department of Mining Electrical Engineering of the Leningrad Mining Institute with one of the coal trusts. Electric motors of two submersible motor-pumps were tested. The design data of both motor-pumps are absolutely identical. Only their electrical parts differ slightly: the stator of the electric motor of one of them (motor-pump No. 7) has slightly larger slot dimensions than the stator of the electric motor of the other motor-pump (motor-pump No. 9). Therefore, 16 wires are laid in each slot of the stator of the electric motor of motor-pump No. 7, and 11 wires are laid in the electric motor of motor-pump No. 9. The main data of the submersible motor-pumps with a star connection of the stator winding of the electric motor are as follows: electric motor power on the shaft Pn = 9.2 kW; voltage Un = 380 V; revolutions n = 2900 rpm. Three-phase asynchronous short-circuited electric motor (Fig. 1); pump capacity Qn = 30 m3/hour; pump head Na = 50 m. The total height of the motor-pump is 1400 mm, the height of the electric motor is 930 mm, the diameter of the unit is 183 mm. The electrical and mechanical parts of the submersible motor-pumps are manufactured by the assembly and mechanical workshops of the trust. Submersible motor-pumps of the proposed design, used for pumping water from wells, compare favorably with those currently existing in the following features.