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Date submitted2023-02-07
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Date accepted2023-06-20
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Date published2024-02-29
Origin of carbonate-silicate rocks of the Porya Guba (the Lapland-Kolvitsa Granulite Belt) revealed by stable isotope analysis (δ18O, δ13C)
- Authors:
- Dmitrii P. Krylov
- Ekaterina V. Klimova
Carbonate-silicate rocks of unclear origin have been observed in granulites of the Porya Guba of the Lapland-Kolvitsa Belt within the Fennoscandinavian Shield. The present work aims to reconstruct possible protoliths and conditions of metamorphic transformation of these rocks based on oxygen and carbon isotopic ratios combined with phase equilibria modeling. Isotope analysis and lithochemical reconstructions suggest that carbonate-silicate rocks of the Porya Guba represent metamorphosed sediments (possibly marls) with the isotopic composition corresponding to the Precambrian diagenetically transformed carbonates (δ18O ≈ 17.9 ‰, SMOW and δ13C ≈ –3.4 ‰, PDB). The chemical composition varies depending on the balance among the carbonate, clay, and clastic components. Significant changes of the isotopic composition during metamorphism are caused by decomposition reactions of primary carbonates (dolomite, siderite, and ankerite) producing CO2 followed by degassing. These reactions are accompanied by δ18O and δ13C decrease of calcite in isotopic equilibrium with CO2 down to 15 ‰ (SMOW) and –6 ‰ (PDB), respectively. The isotopic composition is buffered by local reactions within individual rock varieties, thus excluding any pronounced influence of magmatic and/or metasomatic processes.
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Date submitted2022-10-13
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Date accepted2022-12-13
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Date published2023-07-19
A complex model of a drilling rig rotor with adjustable electric drive
A modified mathematical model of an asynchronous electric drive of the rotor – a drill string – a bit – a rock is considered and implemented, which develops and generalizes the results of previously performed studies. The model includes the following subsystems: a model of an asynchronous drive with vector control; a model of formation of the resistance moment at the bottom of the bit, taking into account the peculiarities of the interaction between the bit and the rock; a model of a multi-mass mechanical part that takes into account the deformation of the drill string; subsystem for the drilling rig energy-technological parameters formation. The integrated model makes it possible to calculate and evaluate the selected drilling modes, taking into account their electro-mechanical, energy and technological efficiency and the dynamics of drilling processes. The performed computer simulation of drilling modes confirmed the possibility of a stick-slip effect accompanied by high-frequency vibrations during bit stops, which may change the direction of rotation of the bit, its accelerated wear and unscrewing of the drilling tool. Long bit stops lead to a significant decrease in the average bit rotation speed, which can explain the decrease in the ROP and increase in energy consumption when drilling in the zone of unstable bit rotation. The model can be used as a base for further improvement of rotary drilling control systems.
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Date submitted2022-04-15
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Date accepted2022-11-17
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Date published2023-04-25
Uranium in man-made carbonates on the territory of Ufa
The paper presents the results of analyzing uranium content in man-made carbonates (scale crusts) on the territory of Ufa based on examination of 42 samples. The median uranium content in the investigated samples stands at 1.44 mg/kg, which is significantly lower than the background values (scales from the Lake Baikal water, a clarke of sedimentary carbonate rocks) and data on other settlements of the Republic of Bashkortostan. Low values of uranium content are probably associated with the effects of the three leading factors, i.e. specific subsurface geology of the territory (gypsum, limestone); types of water supply; water treatment processes for the centralized type of water supply. Spatial distribution of uranium in man-made carbonates is characterized with uniformity, which is disturbed in two cases, i.e. a change of the water supply type (from centralized to individual); and material of the vessels used for boiling the water. No significant differences were detected when comparing samples of man-made carbonates associated with different sources of water supply (the bucket and infiltration types of water intake) and the types of household filters.
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Date submitted2022-01-16
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Date accepted2022-04-06
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Date published2023-04-25
Production of biodiesel fuel from vegetable raw materials
One way to reduce the amount of harmful emissions from diesel fuel could be the replacement of part of the fuel with biofuel. Research is related to the production of biodiesel fuel in three ways: transesterification of vegetable oils; esterification of fat acids extracted from vegetable oil; and hydroprocessing of vegetable oils using catalysts in the diesel hydrotreatment process. Food and non-food oils, monatomic and diatomic alcohols were used to produce biodiesel fuel. Optimal parameters of vegetable oil transesterification have been determined: temperature; raw material ratio (oil/alcohol); mixing speed; time; type of process catalyst. The characteristics of the obtained biodiesel fuel samples were studied and compared with each other as well as with the requirements of EN 14214 “Automotive fuels. Fat acid methyl ethers for diesel engines. General technical requirements” and EN 590:2009 “EURO diesel fuel. Technical specifications”. With regard to the physical and chemical characteristics of biodiesel fuel, the best way to produce it is by transesterification of vegetable oils. However, all fuels can be used as components of a blended environmentally friendly diesel fuel.
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Date submitted2019-05-12
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Date accepted2019-07-22
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Date published2019-10-23
A Modern View of Anomalies in the Metal Groups of the Periodic System of D.I.Mendeleev
The article is devoted to the 150 th anniversary of the Periodic Table of Chemical Elements by D.I.Mendeleev. The fundamental law of nature, discovered by D.I.Mendeleev has anomalies and paradoxes associated with certain groups of metals. When studying the physical and chemical properties of complex metal compounds, many discrepancies can be found, namely, the location of elements in groups, which primarily relate to metals with different valences. By studying the approaches and methods for predicting the arrangement of chemical elements, it can be established that D.I.Mendeleev eliminated many differences for some metals during the formation of the Periodic system of chemical elements. D.I.Mendeleev developed a principle that excludes such errors when finding and discovering new elements. Analytical studies conducted by a Russian scientist helped to calculate the atomic masses and describe the properties of three elements not known at that time – «eka-boron», «eka-silicon», «eka-aluminum», the existence of which was proved and confirmed by subsequent discoveries of scandium, germanium, boron, and gallium. The paper provides a significant assessment of the forecasting of metals in various groups of the periodic system. Changes in the properties of some metals significantly influenced their location in the table of D.I.Mendeleev.
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Date submitted2014-07-08
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Date accepted2014-09-08
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Date published2014-12-22
The development of methods for increasing the efficiency factor of gravitation extraction for fine and ultrafine gold from different genesis placers
- Authors:
- T. N. Aleksandrova
- V. B. Kuskov
The basis for and results of experimental studies for increasing the efficiency factor of gravitation extraction for fine and ultrafine gold from geogenic and man-made mineral formations with high clay content as well as alluvial placers are presented. The clayey gold-bearing placers of the Khabarovsk region in Russia’s Far East were used as the subject of research. These placers contain a substantial amount of fine particle gold and muddy material with hard washability, which are the main reasons for gold losses. One more object of research is a placer located in the Krasnoyarsk region, east Siberia. A special method of interpretation has been created for particle size distribution, using newly developed software which can increase the accu-racy of sedimentation analysis and predict the morphology of gold. It has been proved that one of the most promising ways in which to intensify the gravity processes can be effective preparation, including the chemical dispersion of gold dust before gravitational processing. Exploring the joint effect of sodium hexapolyphosphate and halogen oxidant on the efficiency of processing revealed that the combination of the peptization-coagulation cycles improves gold recovery. Also, the possibility of using concentration tables with various designs for production of rough concentrate is shown. The use of a new round disk concentrated table design enables metallurgi-cal results to be improved in comparison with shaking tables.
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Date submitted2009-10-02
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Date accepted2009-12-23
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Date published2010-09-22
The problems of efficient use of the tumenian reservoirs at final stage of low-pressure gas production and prospects in their solutions
- Authors:
- O. E. Bugriy
The reserves depletion estimation is presented for main (base) fields in the north part of the Tumenian area. The significance of long time production of base fields is shown. The main problems of efficient use are shown for reservoirs at final stage of low-pressure gas field. The methodology associated with solving the problem is formulated for low profitability in low-pressure gas output. The recommendations for State support of subsurface users are prepared for efficient low-pressure gas production and efficient use of reserves at all.
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Date submitted2009-08-29
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Date accepted2009-10-30
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Date published2010-02-01
The unit for gravity concentration of fine particles
- Authors:
- Ya. V. Kuskova
It was made new modification of device for allows increasing recovery, to increase productivity and to lower size of concentrated particles. The device has a deck executed as a circle, which divides into two sectors; each sector has circular rifles with progressively growing height from the centre to periphery of a deck. The table is equipped with the high-frequency step-by-step engine ensuring continuous rotation of a table and submission counter impulses for shear of particles in a direction, opposite to rotation of a table. The quantity of angle sectors can be various. Testing of prototype of a table has confirmed an opportunity of increase of recovery, decrease size of extracted dense minerals and increase of throughput.
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Date submitted2008-11-25
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Date accepted2009-01-02
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Date published2009-12-11
Management of competitiveness of the enterprise in crisis
- Authors:
- A. V. Kichigin
- V. S. Vasiltsov
Feature of anti-recessionary management of the organisation consists in the raised complexity of administrative processes. Financial crisis is shown in shortage of money resources, growth of the delayed creditor debts, falling of sales, discontent of the personnel and other adverse factors. Level of requirements to the heads, making the most important, strategic decisions, increases in a geometrical progression In the conditions of a crisis state most important to reduce one expenses and to increase others which can make the company profitable.