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Date submitted2023-07-04
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Date accepted2023-09-20
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Date published2023-10-27
Structure maintenance experience and the need to control the soils thermal regime in permafrost areas
- Authors:
- Anatolii V. Brushkov
- Andrei G. Alekseev
- Svetlana V. Badina
- Dmitrii S. Drozdov
- Vladimir A. Dubrovin
- Oleg V. Zhdaneev
- Mikhail N. Zheleznyak
- Vladimir P. Melnikov
- Sergei N. Okunev
- Aleksei B. Osokin
- Nikolai A. Ostarkov
- Marat R. Sadurtinov
- Dmitrii O. Sergeev
- Roman Yu. Fedorov
- Konstantin N. Frolov
The risks of reducing the stability of buildings and structures are increasing in conditions of climate change and the active development of the territories under the influence of natural and anthropogenic factors. The main causes include: loss of the bearing capacity of frozen soils, various geocryological processes, errors at the stages of design, construction and operation of facilities. Main actual task when conducting research and industrial operations in the cryolithozone is monitoring and, if necessary, managing thermal processes in the permafrost layers interacting with facilities. In this article the obtained positive experience of various technologies applying at various stages of the life cycle of civil and industrial facilities was analyzed. It helps to eliminate or prevent the structure deformation or destruction under the influence of climate change. The methods of permafrost stabilization used in the oil and gas industry in process of industrial infrastructure development of the fields have been studied – freezing (cooling) of foundation soils during construction on heterogeneous foundations. The solution to the problems of minimizing accidents when locating production wells in the permafrost zone of the Yamal Peninsula is considered using the example of an oil and gas condensate field and restoring of the temperature regime of perennial unfrozen soils in areas of valve units of main gas pipelines. An assessment of methods used to maintain the industrial and residential infrastructure within the northern municipalities that ensure the functioning of the fuel and energy complex of the Russian Federation in the Arctic was made. The systems of thermal stabilization in the foundations of buildings and industrial facilities built and operated on permafrost soils allow to fully use the high strength and low deformability of frozen grounds. It ensures the state's long-term plans of the industrial development in the Arctic.
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Date submitted2023-03-14
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Date accepted2023-06-20
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Date published2023-07-19
The wireless charging system for mining electric locomotives
The electric vehicles development has a high potential for energy saving: an energy-saving traffic control can reduce energy resource consumption, and integration with the power grid provides the ability of daily load pattern adjustment. These features are also relevant for underground mining. The critical element of vehicle-to-grid integration is the charging infrastructure, where wireless charging is promising to develop. The implementation of such systems in underground mining is associated with energy efficiency issues and explosion safety. The article discusses the development and research of a wireless charging system for mining electric locomotive A-5.5-600-U5. The analytic hierarchy process is used for justification of the circuitry and design solution by a comparison of different technical solutions based on energy efficiency and safety criteria. A complex computer model of the wireless charging system has been developed that gives the transients in the electrical circuit of a wireless charging system and the high-frequency field density distribution near the transmitting and receiving coils in a 3D setting. An approach to ignition risk evaluation based on the analysis of high-frequency field density in the charging area between the coils of the wireless charging system is proposed. The approach using a complex computer model is applied to the developed system. The study showed that the wireless charging system for mining electric locomotives operating in the gaseous-and-dusty mine is technically feasible and there are designs in which it is explosion safe.
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Date submitted2022-04-13
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Date accepted2023-02-15
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Date published2023-08-28
The impact of secondary mineral formation on Na-K-geothermometer readings: a case study for the Valley of Geysers hydrothermal system (Kronotsky State Nature Biosphere Reserve, Kamchatka)
The temperature in the Valley of Geysers (Kamchatka) geothermal reservoir calculated using the feldspar Na-K-geothermometer has been steadily increasing over the past 10 years on average from 165 to 235 °C, which is close to the temperature values of a hydrothermal explosion of the steam and water mixture. For the analysis of chemical geothermometers, TOUGHREACT-simulation was used, with the help of which the previously known Na-K feldspar geothermometer was reproduced on a single-element model and new formulas were obtained for three Na-K geothermometers: zeolite, smectite, and based on volcanic glass. Data of chemical analysis for the period 1968-2018, in which the chloride ion is considered as an inert tracer of geofiltration processes, indicates that after 2007 a significant inflow of infiltration water (its mass fraction is estimated from 5 to 15 %) into the Geyser reservoir. It is assumed that the Na-K increased values of the feldspar geothermometer are not the result of the temperature increase in the Geyser reservoir, but the effect of smectite water dilution.
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Date submitted2022-03-17
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Date accepted2022-06-20
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Date published2022-11-03
Assessment of collecting activity of physically sorbed reagents on the example of easily floatable coking coal sludge
- Authors:
- Sergey A. Kondratev
- Tatyana A. Khamzina
The article presents one of the new approaches to theoretical assessment of collecting ability of reagents. The efficiency of reagents-collectors with different chemical composition used for flotation of coking coals was studied. A comparative assessment of the flotation activity of kerosene, mineral oil, thermal gas oil, KETGOL and FLOTEK is given. The criteria of collecting activity of the above reagents-collectors for coal sludge flotation were specified. A correlation was established between the indicators of coal sludge flotation by the above reagents and their physical parameters. It is shown that the rate of spreading over water surface can characterize the flotation activity of reagents. Based on dependence of the collecting activity of a reagent on its rate of spreading along the “gas – liquid” interface and surface pressure, the main approaches to determining the structure and composition of molecules of an effective flotation collector can be determined. A new concept of the function performed by a physically sorbed collector in the elementary act of flotation and a criterion for the flotation activity of reagents used in coal sludge beneficiation are proposed. It is shown that the collector used in coal flotation, in addition to hydrophobizing the surface of the extracted particles, should reduce the induction time and remove the kinetic constraint on formation of a flotation aggregate.
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Date submitted2022-03-14
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Date accepted2022-05-13
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Date published2022-07-26
Unique titanium Deposits of Timan: genesis and age issues
The article critically analysesthe hypotheses about the formation, age, and sources of material of large Timan titanium deposits, which were previously considered ancient buried placers formed along the weathering crusts of the Riphean shales. We discuss an alternative hydrothermal-metamorphic hypothesis about the formation of these deposits and the source of ore material. It is established that the incoming zircon of different ages (570-3200 Ma), as well as two other geochronometers, rutile and monazite, underwent a thermal effect common for all varieties as a result of a hydrothermal process about 600 Ma ago. According to modern concepts, the closing temperature of the U-Pb system in rutile exceeds 500 °С, which suggests high-temperature conditions for the hydrothermal processing of rutile during the formation of the considered deposits in the Riphean.
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Date submitted2022-01-28
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Date accepted2022-04-26
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Date published2022-07-26
On the presence of the postmagmatic stage of diamond formation in kimberlites
- Authors:
- Sergey K. Simakov
- Yuri B. Stegnitskiy
On nowadays multiphase and the facies heterogeneity of the formations are distinguished at the study of kimberlite pipes. Most researchers associate the formation of diamonds only with the mantle source. To date, satellite minerals with specific compositions associated with kimberlite diamonds have been identified as deep mantle diamond association. They are extracted from the concentrate of the kimberlites heavy fraction and may reflect the diamond grade of the pipe. For some minerals in the diamond association, however, they can not be reliable. Some researchers also revealed shallow diamond associations, related to the formation of serpentine, calcite, apatite, and phlogopite. There is recent data on the formation of diamonds in rocks of the oceanic crust. In the last years microdiamonds were identified in chromites of the oceanic crust in association with antigorite formed at 350-650 °C and 0.1-1.6 GPa. As a result, the authors established a postmagmatic kimberlitic stage of diamond formation associated with secondary mineral associations based on the experimental and mineralogical data for the conditions of the shallow upper mantle and crust. Mineralogical and petrographic studies of Angolan kimberlite pipe show that antigorite is the indicator mineral of this stage.
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Date submitted2022-02-18
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Date accepted2022-05-25
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Date published2022-07-13
Remote sensing techniques in the study of structural and geotectonic features of Iturup Island (the Kuril Islands)
The article presents structural and geotectonic features of Iturup Island, the largest island in the Greater Kuril Ridge, a unique natural site, which can be considered as a geological reference. The structural and geotectonic analysis carried out on the basis of a comprehensive study of the new Earth remote sensing data, maps of anomalous geophysical geophysical fields, and other geological and geophysical materials using modern modelling methods made it possible for the first time to identify or clarify the location of previously discovered discontinuous faults, typify them and determine the kinematics, as well as to establish a more reliable spatial relationship of the identified structures with magmatism with the stages of the geological development of the region. The constructed diagram of the density distribution of the zones with increased tectonic fracturing shows a significant correlation between the distribution of minerals and weakened areas of the Earth's crust and can be used as an alternative method for predicting minerals in the study region, especially in remote and hard-to-reach areas. The presented approach can be extended to the other islands of the Greater Kuril Ridge, thereby bringing research geologists closer to obtaining the answers to questions about the features of the geotectonic structure and evolution of the island arc. The use of customized software products significantly speeds up the process of interpreting a large array of geological and geophysical data.
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Date submitted2021-10-08
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Date accepted2022-01-24
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Date published2022-04-29
Methodology for thermal desorption treatment of local soil pollution by oil products at the facilities of the mineral resource industry
- Authors:
- Mariya A. Pashkevich
- Marina V. Bykova
The analysis of the main environmental consequences of leaks and local spills of petroleum products at the enterprises of the mineral resource complex is presented. It is established that the problem of soil contamination with petroleum products at the facilities of the mineral resource complex and enterprises of other industries is caused by significant volumes of consumption of the main types of oil products. Based on the results of the author's previous field research, a series of experiments was carried out, consisting in modeling artificial soil pollution with petroleum products such as gasoline, diesel fuel, highly refined oil, motor oil, and transmission oil, followed by their purification by heat treatment at temperatures of 150, 200, and 250 °C. The 250 °C limit of the heating temperature was set due to the need to partially preserve the structure and quality of the soil after heat treatment to preserve its fertility. When the processing temperature rises to 450 °C, all humates are completely burned out and, as a result, productivity is lost. Confirmation is provided by the results of experiments to determine the humus content in uncontaminated soil and soil treated at different temperatures. It was found that at a maximum processing temperature of 250 °C, about 50 % of the initial organic carbon content is preserved. According to the results of the conducted experimental studies, the dependences of the required processing temperature on the concentration of petroleum products to reduce the concentration of petroleum products to an acceptable level have been established. The methodology of thermal desorption cleaning of soils with varying degrees of contamination at enterprises of the mineral resource complex is presented.
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Date submitted2021-09-02
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Date accepted2022-01-24
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Date published2022-04-29
Complex processing of high-carbon ash and slag waste
The paper considers a current issue of ash and slag processing for the Polyus Aldan JSC, that has accumulated over 1 million tons of this waste. Following the results of the review of Russian and foreign literature, four promising areas of their use were selected: road construction, building materials, reclamation of disturbed lands, and inert aggregates. To assess the possibility of implementing the selected disposal directions, the samples of ash and slag waste of the enterprise were sampled and analyzed. Fuel characteristics, chemical and mineral composition, as well as physico-chemical and mechanical properties of waste were determined. Taking into account the results of complex laboratory studies and the requirements of regulatory documents, each of the selected areas of using ash and slag waste was evaluated. It was found that their disposal by traditional methods has limitations, mainly related to the high content of unburned fuel residues. The high content of combustible substances and the high specific heat of combustion with a relatively low ash content suggested the possibility of thermal disposal of the studied waste. Based on the literature data, the characteristics of the preparation of organic coal-water suspensions based on the studied ash and slag waste were selected. As a result of a series of experiments on their flaring, the expediency of using the obtained fuel at the enterprise under consideration has been proved. The authors note the possibility of using ash obtained after thermal waste disposal in the road construction industry. The prospects for further research of technologies for the preparation and combustion modes of suspension fuel based on ash and slag waste are determined.
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Date submitted2021-11-30
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Date accepted2021-11-30
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Date published2021-12-27
Innovative ways to control dust and explosion safety of mine workings
Ensuring dust and explosion safety during underground coal mining is one of the most important tasks of industrial safety and labor protection departments. The main method of preventing explosions of coal dust settled in mine workings is to process them with stone dust (rock dusting). The traditional methods of quality control of rock dusting include radioisotope, optical and chemical methods. To implement them, the devices are equipped with environmentally harmful radioactive elements, expensive optical sensors, desiccants and replaceable flasks with chemical reagents, which increases the cost of analysis and its duration. The measurement error of these devices is 10 % or more. The main purpose of the study is to develop and substantiate a new method for monitoring the dust and explosion safety of mine workings, which will be devoid of the disadvantages of the methods mentioned above. It is proposed to evaluate the quality of rock-dust distribution by a fundamentally new way – thermogravimetric. The method was tested on the dust of coal mines in Kuzbass and the Vorkuta basin, including dust samples taken in mines with actual explosions. The article presents the results of experimental studies of the processes of thermal destruction of coal and stone dust mixtures. The non-overlapping intervals of the thermogravimetric reaction are identified: moisture yield (35-132 °С); volatile matter yield from coal (380-580 °С); thermal degradation of limestone with carbon dioxide yield (650-850 °С). Methods and mathematical dependencies for processing significant and qualitative identification characteristics of thermogravimetric curves in determining the content of non-combustible components in a sample of mine dust are considered.
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Date submitted2021-02-20
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Date accepted2021-10-18
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Date published2021-12-16
Thermal protection implementation of the contact overheadline based on bay controllers of electric transport traction substations in the mining industry
The article presents the principle of thermal protection of the contact overheadlineand substantiates the possibility of practical implementation of this principle for rail electric transport in the mining industry. The algorithm for the implementation of modern digital protection of the contact overhead line as one of the functions of the controller is described. A mathematical model of thermal protection is proposed, which follows from the solution of the heat balance equation. The model takes into account the coefficient of the electrical networktopology, as well as the coefficient of consumption of the current-carrying core of the cable, which determines the reduction in the conducting section from contact erosion and the growth of oxide films. Corrections for air flows are introduced when receiving data from an external anemometer, via telemechanics protocol. The mathematical model was tested by writing a real thermal protection program in the C programming language for the bay controller, based on the circuitry of which is the STM32F407IGT6 microcontroller for the microcontroller unit. Verification tests were carried out on a serial bay controller in 2020. The graphs for comparing the calculated and actual values of temperatures, with different flow rates of the current-carrying conductor of the DC cable, are given. To obtain data, telemechanics protocols IEC 60870-104 and Modbus TCP, PLC Segnetics SMH4 were used.
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Date submitted2020-06-11
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Date accepted2020-06-11
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Date published2020-06-30
Mathematical model of the liquefied methane phase transition in the cryogenic tank of a vehicle
In order to increase the efficiency of using vehicles (VEH) in mining and quarrying conditions, it is necessary to improve the components of gas equipment (cryogenic tank, gas nozzles, fuel supply cryogenic tubes, etc.) for supplying liquefied natural gas to the engine, as well as storage of liquid methane in a cryogenic tank with a long service life. For this, it is necessary to consider the process of heat and mass transfer of liquefied natural gas in a two-phase liquid-gas medium, taking into account the phase transition in the closed volume of the cryogenic tank under consideration. The article presents a model of unsteady heat and mass transfer of a two-phase liquefied methane medium in a developed two-tank cryogenic tank using a Cartesian coordinate system with fractional control volumes in space. The experimental data confirm the efficiency of using a cryogenic tank on the VEH platform, in which the run on liquefied methane compared to standard fuels is tripled, the shelf life of liquefied gas in the proposed cryogenic tank is 2-2.5 times longer than in the standard one.
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Date submitted2019-07-11
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Date accepted2019-09-11
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Date published2020-04-24
Research of lithium sorption by KU-2-8 cation exchanger from model solutions simulating geothermal fluids in the dynamic mode
- Authors:
- Tatiana P. Belova
- Tatiana I. Ratchina
The extraction of chemical compounds from hydromineral raw materials is currently a promising objective. The geothermal deposits in the Kamchatka Territory should be considered as possible sources of lithium, boron and other chemical compounds. Their economic efficiency is justified by the complexity of the use of resources of geothermal fluids. The article presents data obtained as a result of experimental studies of lithium sorption by KU-2-8 cation exchanger from model solutions that simulate geothermal fluids in the dynamic mode. It was shown that in the first phase of sorption, ion exchange results in the absorption of lithium and sodium ions by the hydrogen form of cation exchanger up to the degree of cation exchanger saturation by 78 %. After that, the displacement of lithium ions by sodium ions is observed. The intermediate solutions were obtained in which the molar ratio of Li/Na is 80 times higher than in the initial solution. To separate sodium and lithium, it is proposed to use the lithium form of cation exchanger obtained using a portion of lithium chloride concentrate. The separation occurs due to the displacement of lithium ions by sodium ions. The effluent has a molar ratio of Li/Na = 10.4. The regeneration is carried out with 1 n hydrochloric acid, while the concentration coefficient of sodium chloride equals three.
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Date submitted2019-07-11
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Date accepted2019-09-04
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Date published2019-12-24
Recent scientific research on electrothermal metallurgical processes
- Authors:
- E. Baake
- V. A. Shpenst
A wide range of industrial metallurgical heating and melting processes are carried out using electrothermal technologies. The application of electrothermal processes offers many advantages from technological, ecological and economical point of view. Although the technology level of the electro heating and melting installations and processes used in the industry today is very high, there are still potentials for improvement and optimization due to the increasing complexity of the applications and the strong requirements regarding the performance and quality of the products but also regarding the reduction of time and costs for the development of new processes and technologies. In this paper recent applications and future development trends for efficient heating and melting by electrothermal technologies in metallurgical processes are described along selected examples like induction heating for forging or rolling of billets, heat treatment of strips and plates, press-hardening processes, induction surface hardening of complex geometries, induction welding as well as induction melting processes.
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Date submitted2019-01-03
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Date accepted2019-03-23
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Date published2019-06-25
Normalization of thermal mode of extended blind workings operating at high temperatures based on mobile mine air conditioners
Thermal working conditions in the deep mines of Donbass are the main deterrent to the development of coal mining in the region. Mining is carried out at the lower technical boundaries at a depth of almost 1,400 m with a temperature of rocks of 47.5-50.0 °C. The air temperature in the working faces significantly exceeds the permissible safety standards. The most severe climatic conditions are formed in the faces of blind development workings, where the air temperature is 38-42 °С. It is due to the adopted coal seam mining systems, the large remoteness of the working faces from the main air supply openings, the difficulty in providing blind workings with a calculated amount of air due to the lack of local ventilation fans of the required range. To ensure thermodynamic safety mine n.a. A.F.Zasyadko we accepted the development of a draft of a central cooling system with ground-based absorption refrigerating machines with a total capacity of 9 MW with the implementation of the three types of generation principle (generation of refrigeration, electrical and thermal energy). However, the long terms of design and construction and installation work necessitated the use of mobile air conditioners in blind development faces. The use of such air conditioners does not require significant capital expenditures, and the terms of their commissioning do not exceed several weeks. The use of a mobile air conditioner of the KPSh type with a cooling capacity of 130 kW made it possible to completely normalize the thermal working conditions at the bottom of the blind workings 2200 m long, carried out at a depth of 1220-1377 m at a temperature of host rocks 43.4-47.5 °С. It became possible due to the closest placement of the air conditioner to the face in combination with the use of a high-pressure local ventilation fan and ducts, which ensured the air flow produced by the calculated amount of air. The use of the air conditioner did not allow to fully normalize the thermal conditions along the entire length of the blind face but reduced the urgency of the problem of normalizing the thermal regime and ensured the commissioning of the clearing face.
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Date submitted2018-11-10
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Date accepted2019-01-17
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Date published2019-04-23
AMT soundings in the dead band within the Chukotka region (Russian Far East)
The article analyzes the amplitude spectra of audio magnetotelluric sounding (AMTs) data. Particular attention is focused on the frequency range from 1 to 5 kHz, which is called dead band. We analyzed the data of base stations used in the fieldwork during the summer and autumn seasons in 2013, 2014, and 2017. The area of work is located in the Chukotka Autonomous Area beyond the Arctic Circle. Previous researchers noted that a reliable signal in the dead band can only be obtained at nighttime. The authors of the article found that in Chukotka region in the daytime against the minimum signal within the dead band there is a local maximum at a frequency of 2.4 kHz. When registering a field for more than 3 hours during daytime, in most cases, it is possible to restore the frequencies of 2.2 and 2.6 kHz. These frequencies are reliable benchmarks, allowing in some cases to restore the AMT curve using the correlation between amplitude and phase. We have proposed ways to improve data quality in the dead band when measured during the daytime.
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Date submitted2018-05-24
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Date accepted2018-07-20
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Date published2018-10-24
Moisture content of natural gas in bottom hole zone
- Authors:
- E. A. Bondarev
- I. I. Rozhin
- K. K. Argunova
For the traditional problem of gas flow to a well in the center of circular reservoir, the influence of initial reservoir conditions on dynamics of gas moisture content distribution has been determined. Investigations have been performed in the framework of mathematical model of non-isothermal real gas flow through porous media where heat conductivity was considered to be negligible in comparison with convective heat transfer. It is closed by empirical correlation of compressibility coefficient with pressure and temperature, checked in previous publications. Functional dependence of moisture content in gas on pressure and temperature is based on empirical modification of Bukacek relation. Numerical experiment was performed in the following way. At first step, axisymmetric problem of non-isothermal flow of real gas in porous media was solved for a given value of pressure at the borehole bottom, which gives the values of pressure and temperature as functions of time and radial coordinate. Conditions at the outer boundary of the reservoir correspond to water drive regime of gas production. At the second step, the calculated functions of time and coordinate were used to find the analogous function for moisture content. The results of experiment show that if reservoir temperature essentially exceeds gas – hydrate equilibrium temperature than moisture content in gas distribution is practically reflects the one of gas temperature. In the opposite case, gas will contain water vapor only near bottom hole and at the rest of reservoir it will be almost zero. In both cases, pressure manifests its role through the rate of gas production, which in turn influences convective heat transfer and gas cooling due to throttle effect.
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Date submitted2018-01-19
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Date accepted2018-03-23
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Date published2018-06-22
Topochemical kinetics of external friction during mechanical and thermal activation of the friction contact
The article deals with the process of contact interaction (relative displacement) of surfaces as a chemical reaction, the regularity of which is described by the Arrhenius equation. The kinetic characteristics of Gersi-Striebeck are obtained taking into account the mechanical and temperature conditions of the frictional contact. The process of interaction of materials in friction in the form of regularities of topochemical kinetics, realized due to the processes of formation and growth of adhesion adhesion nuclei, makes it possible to present the experimental characteristics in the form of theoretical dependences. These dependences reflect the entire range of variation of the coefficient of friction from the speed of mutual movement of materials, including at ultra-low sliding speeds. In the framework of this approach, the lubricating action of the medium prevents and blocks the reactions of the transition of nuclei to actively growing nuclei.
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Date submitted2018-01-23
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Date accepted2018-02-25
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Date published2018-06-22
Influence of post-welding processing on continuous corrosion rate and microstructure of welded joints of steel 20 and 30KHGSA
- Authors:
- A. M. Shchipachev
- S. V. Gorbachev
Welded joints of structure steels have lower corrosion resistance in comparison to base metal. To increase corrosion resistance of welded joints and heat-affected zone they use longtime and energy-consuming methods of thermal and mechanic processing. The article covers the possibility of using the superplasticity deformation (SD) effect for processing of welded joints. The effect of SD is that metals and alloys with a small grain size (of the order of 10 μm) under conditions of isothermal deformation at a certain temperature acquire the ability for unusually large plastic deformations while reducing the deformation resistance. Grain-boundary sliding during superplasticity provides a high degree of structural homogeneity. If the metal does not have the small grain size, then during isothermal deformation at appropriate temperature the SD effect will not be fully manifested but will cause relaxation of residual micro and macro strains, recrystallization, which can be used during processing of welded joints to ensure their full strength. There have been carried out the investigation of processing methods impact - SD, thermal cycling and influence of post-welding treatment on corrosion rate and microstructure of steels 20 and 30KhGSA. It is shown that after deformation in superplasticity mode there is low corrosion rate and more favorable microstructure in the studied samples of steel. Post-welding processing of welded joints in SD mode provides low tool loads and low energy costs.
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Date submitted2017-12-27
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Date accepted2018-03-22
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Date published2018-06-22
Mathematical model of heat exchange processes for heat ptotective cooling suit of a rescuer
- Authors:
- V. R. Alabev
- G. V. Zavyalov
Fires are followed by the range of factors hazardous for human health; a radiant thermal stream accompanied by the high temperature of the environment is one of these factors. For protection of firemen special protective clothing from heat impact and the insulation type clothing are used. The paper demonstrates that the concept of action of such clothing is based on the passive heat protection owing to the use of materials with low conducting capacity or high specific heat. The time of effective protection of a suit is not considerable which reduces the duration of work under the unfavorable climatic conditions drastically, increases the work labor input, leads to the hyperthermia. One of the ways focused on the improvement of the heat protective clothing is a design of suits with cooling, which is stated in the paper. The paper shows that the developed heat protective suits on the basis of water-ice cooling elements are not widely used due to considerable costs. A more reasonable idea refers to the design of heat protective suits with cooling by using running water as the most available coolant circulating along polyvinylchloride pipes arranged between the layers of a suit.
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Date submitted2017-10-26
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Date accepted2017-12-25
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Date published2018-04-24
Conditions of austenite diffusional transformation in steel of Cr–3Ni–Mo–V-composition with high austenite stability
- Authors:
- V. V. Tsukanov
- N. V. Lebedeva
- Yu. M. Markova
The paper investigated the bainitic steel of 10KHN3MFA grade, which is characterized by the increased tendency to display structural heredity in the forgings with large cross-sections. The samples have been studied for kinetics of diffusional transformation process both under continuous cooling and isothermal conditions, as well as its microstructure. It is determined that in the range of subcritical temperatures with cooling from 900 °C in the studied steel, the initial stage of separation of the ferrite phase takes place. It is shown for the first time that the diffusional ferrite-pearlite transformation fades. Previously it was believed that the beginning of transformation under isothermal conditions proceeds to the end. It was found out that the transformation begins immediately after the beginning of isothermal holding, without the generally accepted incubation period.
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Date submitted2017-08-30
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Date accepted2017-11-23
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Date published2018-02-22
Basic provisions and problems of ELW technology for the manufacture of aluminum-magnesium alloys constructions
- Authors:
- E. I. Pryakhin
- N. I. Sharonov
Existing problems of electron beam welding of aluminum alloy constructions are considered. For research purposes, the aluminum-magnesium alloy of grade 1561 up to 60 mm thick was used. The thermal field in the heat influence zone is studied experimentally and analytically on the basis of the finite element method (the «Ansys» program). The effect of electron beam movement (scanning) influence on the quality of welded connections and the surface of the welded parts was studied. On the basis of metallographic studies and mechanical tests of welded metal, it is proved that high quality of welded joints is ensured when the beam moves along a curve of the «compressed brackets» shape. A special generator is designed to control the electron beam, which allows to implement a new type of scanning (compressed brackets). The fundamentals of welding technology for alloy 1561 up to 60 mm thick are outlined. Specific recommendations are given, and two new methods are proposed that will allow the successful use of the developed technology in factories in the production of new products and in the repair processes. Examples and analysis of thermal cycles obtained by calculation and experimental method are given. The patterns of heat distribution along the trajectory of the beam movement for different types of scanning are established. The main types of defects in the formation of the welded joints and those formed in the metal during crystallization are considered. Their interrelation with the parameters of the welding mode is shown.
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Date submitted2016-10-27
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Date accepted2017-01-02
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Date published2017-04-14
Chemistry as a basis for solving environmental issues
- Authors:
- V. E. Kogan
- T. S. Shakhparonova
The article summarizes over 40 years of authors’ experience in the field of physical chemistry and chemical technology of glassy state of materials. It is shown that environmental issues are caused not by Chemistry as a science but by actions of ecologically illiterate humans using its advances. It is noted that without chemistry humankind cannot live comfortably and solve existing environmental problems. In support these facts we describe several developments made by authors of this article in energy industry, high temperature machinery, glass production technology, glassy phosphate fertilizers, production of non-waste systems and complex research of physical-chemical principles of glassy oil sorbents production of organic and non-organic nature.
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Date submitted2016-11-01
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Date accepted2017-01-20
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Date published2017-04-14
Technology and economics of near-surface geothermal resources exploitation
- Authors:
- E. I. Boguslavskii
- V. V. Fitsak
The paper presents economic justification for applicability of near-surface geothermal installations in Luga region, based on results of techno-economic calculations as well as integrated technical and economic comparison of different prediction scenarios of heat supply, both conventional and using geothermal heat pumps (GHP). Construction costs of a near-surface geothermal system can exceed the costs of central heating by 50-100 %. However, operation and maintenance (O&M) costs of heat production for geothermal systems are 50-70 % lower than for conventional sources of heating. Currently this technology is very important, it is applied in various countries (USA, Germany, Japan, China etc.), and depending on the region both near-surface and deep boreholes are being used. World practice of near-surface geothermal systems application is reviewed in the paper.
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Date submitted2016-10-26
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Date accepted2016-12-29
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Date published2017-04-14
Inversion modeling of the natural state and production history of Mutnovsky geothermal field in 1986-2006
- Authors:
- A. V. Kiryukhin
- O. O. Usacheva
Numerical 3D model of Mutnovsky geothermal field (Dachny springs), which consist of 517 elements and partially takes into account double porosity, was developed in 1992-1993 using computer program TOUGH2. Calibration of the model was based on data from test yield of the wells and initial distribution of temperature and pressure in the reservoir. This model was used for techno-economic justification of power plant construction (Mutnovskaya GeoES, 2002). The model was recreated in the program PetraSim v.5.2, the calibration was carried out using additional data on production history before year 2006 and inversion iTOUGH2-EOS1 modeling. Comparison of reservoir parameters, estimated using inversion modeling, with previous parameter estimations (given in brackets) showed the following: upflow rate of heat-transfer agent in natural conditions 80.5 (54.1) kg/s, heat flux enthalpy 1430 (1390) kJ/kg, reservoir permeability 27∙10 –15 -616∙10 –15 (3∙10 –15 -90∙10 –15 ) m 2 . Inversion modeling was also used to estimate reinjection rates, inflow of meteoric water in the central part of geothermal field and compressibility of reservoir rocks.